Big Burn: North American Great Plains fire layer re-proposed by Wisconson

 

image_1944-Brady-soil

A paper this week from the University of Wisconsin announces a predictable conclusion to readers of the Tusk: The transition from the Pleistocene to the Holocene is characterized by soil signatures of fire on a continental scale. The author’s geochemical analysis is helpful and welcome, but my children would have a pretty good shot at guessing what happened in olden days by simply looking at the photo above — Looks like there was a big fire, dad.

Equally obvious to me (perhaps not the kids) is the conspicuous absence of any citation to the Firestone papers. It would seem that multiple major journal publications providing much more detailed evidence of frightful temperatures and horrendous fires within the period of Marin-Spiotta et al.’s own study of the same region would merit a reference in support of their hypothesis. But alas and for shame it does not.

Download (PDF, 1004KB)

  • Cevin Q

    I found that paper this weekend, very interesting.
    So, we have a carbon layer in island California, that has all the hallmarks of massive fires, we have a carbon layer at Clovis era sites that was deposited on the sites themselves.
    And now the Brady layer of the Midwest, shows that there were massive fires in the mid west , during the same period.
    Hmmmm

  • Trent Telenko

    That is a whole lot of carbon over a continent sized area.

  • Steve Garcia

    CevinQ –

    As I read that article/paper, I understand that their Brady layer is at about 15,000 ya, so that would not be contemporary with the black mat at Murray Springs or Gainey, etc.

    At the same time, because it is CLEAR from the photos that there are not TWO black layers but only one, that there could not have been both a Brady layer AND a separate YDB black mat.

    Since the Brady layer seems to be in the same region as the YDB black mat, this gives us two possible solutions:
    1.) Either the Brady mat was VERY regional ( a small area) or
    1.) The Brady layer is mis-dated.

  • Steve Garcia

    It is pretty impossible to look at the photo of that black layer and not conclude, “Something BIG happened.”

    Then you look at the volume of it. It is about a meter thick.

    Now, look at the foliage around there. Even living, the foliage doesn’t amount to a meter high.

    Whatever happened – and it certainly was a fire – the fuel for the fire had to come from much more foliage than is now growing there.

    What does that tell us? That the climate must have been not only probably warmer, but also wetter.

    Now, at some sites – even at Blackwater and Murray Springs – the black mat actually was at least partly algal – indicating not only a little wetter, but standing water like bogs and swamps and ponds. The climate then had to be SO different than now.

    The standard mainstream line on that is that the ice sheet edge was so much farther south that it meant that the climate was much milder, more temperate. That may make sense in a simplified south=warm/north=cold equation. However, when we look directly north of Nebraska, almost as far as we look there are still fairly barren plains. Cooler right now does not translate into more flora. One has to go all the way to the Mississippi River, pretty much, to find a lot of foliage.

    The Great American Desert is where that Brady soil is found. Compare this map from 1819-1820 with the map in the paper. “Great Desert” is exactly the same place, in Nebraska. Now, all deserts are not like Namibia, with 200-foot-high sand dunes of nothing but sand. Even the Sahara has a lot of rock outcrops where there is little sand. But from accounts of the early settlers, the Great Desert was a place that would not support agriculture. People who tried generally failed and failed big time.

    And one last point about that photo of the black Brady soil layer: Notice how much dirt is overlying that black layer. At the Clovis sites and other sites from Firestone and other YDB researchers, their “black mat” is only about one meter below the surface. The Brady soil is about 6 meters below. I don’t know what it means yet, though I have guesses.

    But I reiterate my point from above – based on the other sites to the south and west and northwest – and even in Michigan – the black mat should not be at two different times, nor are there ever TWO black mats.

    At this point I think the Brady soil dates are wrong.

  • Cevin Q

    Steve,
    The dating of the Brady soil isn’t that big of a hurdle, and I’m fact might help make sense of things.
    It’s clear from Napier and Clubes work that in the early life of the taurid complex was more accurately described by a swarm of impacts more than a single large one.
    So, it not that hard to see a period of years that are punctuated by impacts or swarms of impacts.
    Maybe the major impact over the laurentide ice sheet was the first, followed by several other episodes of impact spread around the planet over time. This actually helps resolve the dating incongruity shown by sites that have a carbon layer.

  • Steve Garcia

    Dammit! I forgot to past in the link to the Great American Desert map of 181901820.

    http://www.colorado.edu/AmStudies/lewis/west/desert.gif

  • Steve Garcia

    I’d like to discuss this paper’s dates as they might pertain to the YDB.

    First of all, I wrote the lead author, who told me that the dates ARE calibrated, using IntCal09, via the program Calib v.6. Thus what I wrote above is wrong. The dates are NOT 15,000 ya or so.

    My bad.

    In the text is this:

    Before the formation of the Brady soil, rates of local loess accumulation during the Pleistocene have been estimated at a remarkable 4 mkyr−1 (refs 3,13,14). Formation of the Brady soil initiated between 15,500 and 13,500 calyr BP, during a time period of much slower dust deposition (0.1–0.2 mkyr-1), which allowed for pedogenesis and the accumulation of SOM (refs 3,13,14). Increasing rates of loess deposition over time, estimated at 0.72–0.80 mkyr−1, buried the Brady soil approximately 10,500–9,000 years ago.

    So we have three quite distinct periods of accumulation demarcated:
    1. Pre-Brady = 4.0 m/kyr
    2. Brady soil = 0.1-0.2 m/kyr
    3. Post-Brady = 0.72-0.80 m/kyr

    The period we are interested in is the transition from Pre-Brady to Brady. We’d like to see if that corresponds to the YDB, and if the Brady soil might equate to the black mats at other sites.

    If we assume that there was some mixing at the transition periods into and out of the Brady soil deposition, then the transition into is from 4.0 m/kyr to about 0.15 m/kr.

    Questions:
    1. Can we assume a good deal of mixing?
    2. Can we find any evidence that such mixing occurred (without me going to Nebraska…LOL)?
    3. Can we also find any evidence for such mixing also happened at the end of the Brady soil, as the deposition goes from 10.15 m/kyr to 0.80 m/kyr?

    I think I can point at something that LOOKS like such evidence.

    Questions 1,2, and 3 should predict:
    A. That some noticeable transition layers exist
    B. That the lower transition layer is wide, due to greater mixing
    C. That the upper transition layer is less wide, due to less mixing

    Now, go take a look at the photo at the top of this post. I exported it to where I could enlarge it as much as I wanted to.

    I see:
    a.) A lower loess layer that is light brown or sandy-looking
    b.) An upper loess layer that is a slightly different color than the lower loess layer.
    c.) A middle and most dark layer of the Brady soil.
    d.) A fairly wide tawny transition layer between the lower loess layer and the Brady soil
    e.) A much narrower transition between the Brady soil layer and the upper loess layer.

    I would suggest that the tawny layer is the mixing between the loess and the Brady soil.

    You may be asking why this is worth discussing.

    The dates given in this paper in Table 1 only refer to two layers. One is the “modern” layer, at 0.0-0.12 meters deep. The other is at a depth of 6.35-6.50 meters deep.

    That latter soil is 15 cm wide (6 inches), which is wider than the black mat in some locations.

    I submit that that is too wide for accurate dating of the Brady soil beginning – which would equate to the underside of the black mat elsewhere. With the mixing, I think the samples are tainted – with younger soils being measured along with older ones. After all, the black mats elsewhere are dated at ~12,800 ya at the underside, while the upper side is dated at ~11,500 ya. Taking a 6″ wide sample would give a date of about the middle of that – or about ~12,150 ya. The middle of the numbers for “Bulk soil” in Table 1 is 11,655 ya.

    Table 1 does not specify where the 6.35-6.50 sample was taken, relative to the underside of the Brady soil. (Perhaps with the tawny transition mixing the underside layer is not easy to determine…)

    With a 100 cm thick Brady soil layer, it seems quite important for our purposes to know if the 6.35-6.50 sample(s) was taken near the top or bottom or middle of the Brady soil. It is also important to try to measure as close to the underside of the Brady soil layer as possible. (The apparent mixing will distort that sample, though.) It would seem to be very useful to date just under the Brady layer transition.

    The dates right now are apparently about 495 years apart. I would suggest that someone sample more precisely. The 15 cm sample was good enough for the purposes of the authors of this article. But it is not good enough for dating the Brady soil vs the YDB onset.

    Prediction:
    The date differences will disappear when more precise samples are taken and dated. This would show that the Brady soil is, in fact, the same thing as the black mat, at least chronologically.

    Of course, other tests should be run on the composition and then comparisons made, looking for carbon spherules and other materials found at other YDB sites.

    It all sounds like a good paper for someone!

  • Trent Telenko

    I have been chewing on the mega-flood idea for the post-YDB event era in the comment section of another post, but the thought that jumped out at me there seems to apply here as well. The thought being that heat that can melt glaciers are not going to be good for plants in the general area.

    In WW2, the use of napalm incendiaries in Philippine rain forests showed that while they were insufficiently hot to start wide ranging fires — as the foliage was too moist — that about three days after the burn, all the plants in the immediately adjacent heat affected area outside the burn zone lost foliage to heat damage.

    These affected plants and dead foliage were very vulnerable to repeat napalm attack. The Summer 1945 Sphinx Tests by the US Army was looking at that fact as a way of starting crown fires in Kyushu for the cancelled by A-bomb Operation Okympic Invasion.

    That example leads to the thought that if we are looking at a Jupiter style “string of pearl” near-simultanious impact event, that large overlapping areas of North America would be “heat pulsed” such that there would be huge near Napalm attack-style plant heat affected zone would cover huge areas.

    Areas that would be subject to any sort of natural ignition source, like lightning, to set off dramatically huge grass and forest fires.

    This idea means that the “Black Mat” isn’t simply the result of a singular impact event.

    What we are looking at with the “Black Mat” is a much longer post-impact process. In so many words the “Black Mat” could be the result of a huge amount of heat affected plant mass getting set off by normal, natural, means over time, but with a huge continent wide heat affects zone for fuel.

  • Trent Telenko

    Make that:

    “…cancelled by A-bomb Operation _Olympic_ Invasion.”

  • Trent Telenko

    Okay, this was from an internet search on military uses of crown fires. It is from the Vietnam era rather than the end of WW2, but it is quite useful in terms of post-impact energy budgets for possible “Black Mat” fire damage as well as carbon loading from same.

    FOREST FIRE AS A MILITARY WEAPON
    FINAL REPORT
    JUNE 1970
    U.S. DEPARTMENT of AGRICULTURE
    Forest Service

    DTIC Accession number AD509724

    Page 4

    FOREST FIRE EFFECTS
    When considering forest fires as a potential weapon. certain advantages and limitations must be kept clearly in mind. The greatest single superiority factor of fire as opposed to other damage-causing agents, is that under the proper circumstances fire is self-propagating. A relatively large area can be covered with a minimum expenditure of ordnance. The burning of the U Minh Forest in March and April 1968 resulted in a burned-over area of more than 1000 square miles from an expenditure of 20 aircraft sorties and 36 naval gunfire support missions (see Appendix A). The damage caused by this fire was equivalent to that of a 20 megaton nuclear device.

    In 1968 a thousand square miles of forest that burned over two months from the american military ignition of them and that caused the same damage as an instant 20 megaton thermonuclear device!

    The bottom line here is that the usual suspects criticizing the YDB event impact theory on the grounds of excessive energy budgets and lack of craters just had those two “rugs’ pulled out from under them.

  • Trent Telenko

    This is from the same search, different article:

    Capabilities of Nuclear Weapons.
    Part 2. Damage Criteria. Change 1.
    Chapter 15. Damage to Forest Stands. Sanitized
    Dolan, Philip J.
    DEFENSE NUCLEAR AGENCY WASHINGTON DC

    July 1, 1978
    DTIC Accession# ADA955399
    Code A – 01 – APPROVED FOR PUBLIC RELEASE

    page 15-52

    SECTION III
    THERMAL RADIATION
    I Under certain conditions, a nuclear weapon
    that is exploded over a forest or wildland area
    may cause fires. During the fire season, even when
    the burning potential (a measure of probable fire
    aggressiveness) is low. fires may spread. If fires
    are started in regions of sufficient fuel density
    when the burning potential is dangerously high,
    complete evacuation of personnel and equipment
    may be necessary. Organized control of the spread
    of the fire is virtually impossible until changes
    in weather ur fuel availability reduce the burning
    potential.

    15-7 Ignitions
    Wildland fuels are typically a mixture of
    thin and heav) fuel components. Often, the
    thinner fuels will establish the limiting radiant
    exposure that will be required to start fires in the
    mixture.

    When fuels are dry, ignitions that have a
    reasonable chance of surviving the subsequent
    blast effects and of initiating fires that can represent
    a hazard to military personnel in the forest
    can be expected. At quite low levels of radiant
    exposure, For example, broadleaf and coniferous
    litter (mixtures of fine grass, broken leaves and
    duff, and thin translucent broadleaf leaves) can
    be ignited by exposures of 2 to 3 cal cm^2 from
    l kt low-altitude air burst, and heavier leaves
    (dead grass, conifer needles, and fallen, nearl)
    opaque broadleaf leaves can be ignited bs exposures
    between 3 and 4 cal cm^2,
    which correspond
    to distances at which 2 to 3 psi peak
    overpressures might Occur, provided the full freefield
    radiant exposure falls on these fuels.

    The intersting thing for me regards these two documents is the lack of awareness of the Summer 1945 research as well as the inability to see that non-immediate damage to flora could cause more intense fires, naturally, later.

  • Steve Garcia

    Trent – One point for the moment…

    “a Jupiter style “string of pearl” near-simultanious impact event”

    SL-9 was strung out in a line with the fragments hours and hours apart, over a period of like three days (off the tip of my head). Such timing on the Earth would have fragments landing all around the planet. But one thing noticeable on Jupiter (as I pointed out over a year ago) was that, even though spaced apart in time, the fragments all seemed to land at about the same latitude, because the same point on the sphere would be aimed at by all the fragments (or very close), and only one latitude would rotate past that point within the few days.

    Longitudes would be all over the place, as far as I can see. With one hour being 15° of longitude, “simultaneous” impacts would be spread out quite a bit.

    In this I am disagreeing with Bill Napier, because he is on record as saying the impacts would all occur within an hour or so, and him being the expert, he is probably right. But SL-9 sure doesn’t argue on his side. A string of pearls IS a string of pearls because of their separation along their orbit – and this equals time between impacts.

  • Steve – I think it would depend a lot on what caused the disruption. As I understand it, the L-S9 string of pearls was created via a tidal disruption of the comet during a close pass at Jupiter. We haven’t seen that sort of string when a comet simply crumbles like Linear / S-W outside a strong gravity field. The light pressure of sunlight on the fragments along with jet action from the freshly exposed surfaces would also serve to scatter them from the parent body, adding to whatever initial velocity the disintegration would impart. Hubble photos follow. Cheers –

    http://www.spacetelescope.org/images/opo0114a/

    http://www.thunderbolts.info/tpod/2006/arch06/060505cometbreakup.htm

    Dumb question for George: Was there a new post up for a few hours (days?) and then removed or was I seeing things?

  • SL-9’s string of pearls effect was a result of the progenitor object passing so close to Jupiter’s intense gravity well on that first pass as it was drawn into a capture orbit that uneven tidal forces as it did so broke it up, and pulled the fragments into a line; sort of like droplets of water pouring one drop at a time over the edge of a table

    Without those kinds of strong tidal forces acting during close passage like that to a powerful gravity well like Jupiter’s it’s difficult to imagine another comet breakup mechanism that might be able to line up all the fragments so that they come whistling out of the sky in single file, one chunk at a time. I’m afraid the puny excuse for gravity that keeps us all tied down to this little dirtball we call Earth just doesn’t have the juice. And there is a good chance that the string of pears effect is the rarest of the rare.

    On the other hand we commonly see icy bodies like Linear, or S/W-3 breakup in the inner solar system, apparently as a consequence of the volatiles holding them together sublimating away until they just come apart like the wings of Icarus. And they do so without the gravitational influence of any planet.

    If an icy body a hundred times wider than Linear were to completely come apart into a cloud of fragments, and dust, the way Linear, and S/W-3 did, but on a truly gargantuan scale, and if the Earth’s passage along her own orbital path, which is something like 8.4 time her own diameter in an hour, happens to take her through the resulting debris streams soon after that breakup then you have a picture of what kind of event Professor Napier’s work describes.

  • Steve Garcia

    agimarc –

    As usual, great links.

    Linear article: “…the fundamental building blocks that comprised LINEAR’s nucleus may be somewhat smaller than current theories suggest.”

    Schassmann-Wachmann 3 article: “…comet Schwassmann-Wachmann 3 has been rapidly breaking apart, provoking another round of second-guessing by astronomers.”

    I KNOW I am tough and dismissive of many current theories about how things work in the cosmos (and in the Earth’s past), but this is right along my normal ridicule, even though I want to respect these folks. I have a folder and a tab folder both basically entitled, “Science Does It Again.”

    What does it do?

    It strikes out. As in it isn’t science if it can’t predict correctly.

    When they ADMIT such things as blah, blah, blah aren’t as “current theory suggests”, they are saying, “WE GOT IT WRONG.” To which I will add: AGAIN./b> And “No sh**, Sherlock.”

    When they ADMIT such things as that they have to “go through another round of second-guessing,” you know WHAT? It is just another cowardly way of saying “WE GOT IT WRONG.” To which I will add: AGAIN again.

    HOW MANY TIMES DO THEY HAVE TO GET THINGS WRONG BEFORE WE ACTUALLY SAY OUT LOUD THAT THEIR CONCEPTS ARE WRONG AND THAT WE TAXPAYERS SHOULD STOP PAYING THEM FOR GETTING IT WRONG?

    Academia is an INDUSTRY, and its main function is to give paying jobs to academics. The rest is a snow job.

    I would not be saying this if they got things right.

    Until we ditch our belief – our faith in them – that they know what they are talking about, we as humans will never get any of it right.

    READ MY LIPS: THEY ARE FAKING IT AND HOPING AGAINST HOPE THAT WE WHO FUND THEM WILL NOT WAKE UP TO THEIR COLLECTIVE CON GAME.

    Folks, I am not a conspiracy nut. Ask my two best friends who try constantly to get me to join them in their tin foil hat crap. I have them ready to pull their hair out because I don’t fall for the same illogic that they do.

    I only come to this opinion about scientists’ paradigms (not them personally but just that they have swallowed the wrong paradigms and that has worked them into a corner. It has taken me decades to disrespect so much of what they do. If they start from the wrong foundational concepts, they simply MUST come to wrong conclusions.

    Their major misconception is that gradualism is always the rule. That makes them project wrong ideas into the past natural history of the planet and galaxy – and then build houses of cards upon those wrong concepts. Secondly, they have accepted a few principles as true that aren’t. Thirdly, they have rejected some principle as invalid which have very decent evidence pointing that way. Fourthly, they make quantum leaps in logic that are untenable. . . .

    Details somewhere along the line.

    More on the particulars of the articles in the next comment. . . .

  • Steve Garcia

    Wow, I will have to forestall the particulars and vent some more:

    In the Scwassmann-Wachmann article, over and over it points out exactly the points I made just before, but the real DOOZY is this one:

    “Meanwhile, the “explanations” proposed for the comet’s catastrophic fate can only diminish confidence in today’s comet science. Even in the face of falsifying discoveries, the specialists appear unwilling to reconsider their theoretical starting point.

    OY VEY! Do you know what this means? “Falsifying discoveries” means that their expectations (guesses) based on current theory came out WRONG, showing clearly that THE THEORY IS WRONG. The theoretical starting point means that they made a wrong turn and went down a blind alley – and that they need to back up and re-think starting at that point (if not earlier).

    But the astronomers are going to stick to their NOW DISPROVEN HYPOTHESIS – which no longer HAVE the status of “hypothesis”, because the hypothesis has been empirically shown to be wrong.

    FIRE THAT SCIENTIST.

    Oy vey.

    I give this science writer some credit for calling a spade a spade. I wonder how long he will retain his position, since he didn’t suck up to the academic.

  • Steve Garcia

    “have the status” = “has the status”

  • Steve Garcia

    agimarc –

    Take a look at this video of three days of the falling apart of SW-3: http://www.spacetelescope.org/videos/heic0605b/

    Maybe it is just me, but I see the fragments beginning to coalesce into a line, falling farther and farther behind the coma and stretching out – for all intents and purposes what SL-9 did after breaking up on its previous pass by Jupiter. The fragments are clearly falling farther and farther behind – and also tending toward lining up behind the main body.

    The first two photos in your SW-3 link show the same thing, as I read the photos.

    All of those are in April 2006.

    In July of 2013 they all look like a “string of pearls” – https://www.ast.cam.ac.uk/~jds/images/29p_outburst2013dp.jpg

    So your statement that, “We haven’t seen that sort of string when a comet simply crumbles like Linear / S-W outside a strong gravity field,” does not seem to hold true. It is SPECIFICALLY SW-3 that DOES line up in “that sort of string.”

    I had no idea what the evidence would show when I went looking to verify your point. If it had showed the opposite, I would admit that my point is wrong. But here, once again, we not only see that the string of pearls exists, but we see it in the early stages (and probably elsewhere in all of the stages) of being pulled into a line.

    So, my point seems to be correct about fragmented comets being in a line, and thus their impacts on Earth would also be strung out in time.

    * * *

    Another point I’d make is this: I’ve said this before, last year, that these objects are MUCH less well held together than scientists are telling us. The particles and rocks that make them up are only lightly held together, in what I discovered are referred to as “strengthless bodies.” A feather could push them apart. In this last year I’ve seen more and more on strengthless bodies, and it appears that some astronomers are beginning to see that this is common. It is early in the game on strengthless bodies, and I think we will begin to learn more and more about them.

    Of course, Linear’s 330-foot fragments may not be strengthless, and they probably are not. But I keep asking here how solid rocks can form in deep space. In our time we SEE objects falling apart, but we don’t see any combining. That alone should by uniformitarian standards argue against such combining.

    * * *

    At http://www.universetoday.com/88494/comet-elenin-could-be-disintigrating/ we have an article about comet Elenin and its break-up in August 2011.

    “Another Australian amateur Michael Mattiazzo has been taking images of the comet (see his website, Southern Comets) and he has noticed that the nucleus appears to be elongating. When that occurs, usually the comet disintegrates or splits apart.

    Now, solid rocks cannot elongate. But strengthless bodies can. Elongation very much implies that the body is essentially NOT held together strongly and is able to morph its shape even with the very small forces available out in space.

    * * *

    So why do comets string out in a line when they break up? Well, one is tempted to point at cometary tails and suggest that that is exactly what is happening then, too: The solar wind seems to have enough induced drag to push the particles ever slightly. Newton’s First Law and all that. The unbalanced force of the solar wind, combined with the pre-existing velocity and the force of whatever pushed the fragments away from the main body in the first place would seem to slow the fragments down but to also push them all in the same direction. The small gravity of the main body along with the solar and planetary gravity all act together. I’d think the fragments’ paths oscillate back and forth in the plane of the main body/ center of gravity of the “cometary system” – the combined gravity of the main body and all the other fragments and dust. The magnitude of this oscillation of each fragment should dwindle over time, due to the drag of the dust. After all, the fragments aren’t the only thing that separates from the main body. (I use the term “main body” loosely.)

  • Steve, if you followed the fragments of SL9 back to the point where they begin to diverge, and you plot the trajectory of the pre-breakup progenitor you will see that the breakup did not happen AFTER the close pass, but DURING it. So you get the path of the object before it gets caught by Jupiter, and if you follow that path down close to Jupiter and plot the point where line changes direction into a new, and rapidly deteriorating, Jupiter centric orbit, you’ll see that the point of divergence of SL-9’s fragments is exactly the same as the point where jupiter’s gravity slingshots the thing into its new capture orbit. The center of that trajectory change, and fragment divergence, was the object’s perijov. And that was probably so close iit was scimming across the tops of the Jovian atmosphere. In short, SL9’s breakup on that first pass was probably sudden, and violent. And the whole process bares no resemblance whatsoever to the processes that broke up the afore mentioned comets.

  • Steve Garcia

    Yes, Dennis. Of course the breakup of SL-9 happened AT the close encounter with Jupiter. At the same time, I would say that the stringing out in a stright line happened over time. Look at the SW-3 video and you can see that the fragments took some days to begin falling in line behind the main body. That is no delusion of mine but real.

    And yes, the path was changed as the entire SL-9 mass was captured by Jupiter. I mean, that is what happens when a planet captures a comet.

    On the other hand, unless the body actuall DID skim the top of the atmospeher of Jupiter, I’d argue that the breakup begain as it closely approached Jupiter, before perigee, and that the maximum disturbance was AT perigee, as you say. The gravitational attraction didn’t all of a sudden spike and cause the breakup; it gradually increased as a factor of d^2 as d decreased. I think it is a fallacy that such breakups are abrupt. There is no need for abruptness. Gradual force increases will suffice. If you do the math for each point along the comet’s orbit, you will see that the force increase is gradual. It’s all in the math.

  • I’m afraid I ain’t buyin’ the idea that the comet’s fragments are spontaniously, and dutifully ordering them selves into a string of fragments like SL9 without the gravitational influence of a nearby planet. But if such a thing is happening then what imaginary forces does your fantasy include for a motive/organizing force to do so?

  • During SL9’s breakup you had one force, momentum, trying to take the comet one direction. And during that close pass of Jupiter you had jupiter’s gravity trying to pull it off that path. The difference between the two, and the fact that the object wasn’t strong enough to withstand the resulting stress during that close pass is what gave us the string of pearls.

    Without the influence provided by close passage to a very powerful gravity well you’ll have to come up with a completely different mechanism to organize to fragments into a “String of Pearls”

  • I also don’t get the cognitive need to believe that the YD impacts must have been the same kind of plop, plop, plop, one big chunk at a time, series of impacts we saw at Jupiter. If we had a bunch of craters all at the same latitude, maybe. But so far not even one impact site of the correct age has been confirmed. Yet we have overwhelming evidence of continental scale fires like you might expect if the Earth were to pass through a dense cloud of commetary debris.

    We know what the geomorphology of a solid kinetic impact is. But what kind of geomorphology do we expect from 10,000 Tunguska’s?

    Our evidence points us to a completely different kind of impact event from anything that’s ever been imagined, our studied before. So if you are looking for planetary scarring of the kinds of single fragment impacts that produce craters and that we’ve all seen before I’m afraid you’re barking up the wrong tree. But if you want to go looking for a way to show that very large airbursts have hit a given area in the past you might be on to something.

  • Barry Weathersby

    Two questions:

    Why would a ‘string of pearls’ (looks more like every fifth round is a tracer to me) have to all impact at the same latitude? Seems to me that would only happen if they were pulled into an equatorial orbit. Shouldn’t anything approaching at an angle to the equator leave it’s trail across numerous latitudes? What if it approached from north or south? Would that not cause a polar orbit? The string could rip right up (or down) the Atlantic or Pacific and leave no evidence on land. Or am I just picturing it wrong?

    And it makes sense that a large cloud of smaller debris could cause major a climate disaster without leaving as much evidence on the planet’s surface. But what about ice? http://www.dailymail.co.uk/sciencetech/article-2051929/Huge-disc-cold-water-space-gives-clue-origin-oceans–hints-Earths.html If this big dirty slushy snowball has enough H2O in it, on it, around it, I would think the effect would be much different than solid rock impacts.

  • Barry, Jupiter’s gravity not only stretched those fragments out along a line, that line was along their new line of travel. So, once it was deflected from it’s original path and once the fragments began falling back towards Jupiter in a capture orbit, then all of the fragments were falling towards the very same point relative to Jupiter’s center of gravity. So they all hit exactly the same latitude, but at different longitudes as the planet rotated beneath.

    Now, if a comet were to get broken up in a similar fashion during it’s passage through perihelion we might see it emerge from behind the sun as a string of pearls. And just like SL9 the string will be distributed along the orbital path of the comet. If that orbit crosses that of the Earth then we have the potential for a celestial train wreck at the crossing point with one or more of the fragments. But since they would not be falling towards the Earth’s CG in a capture orbit, it’d just be a simple traffic jam. So if more than one hit, they’d be all over the place

  • Steve Garcia

    Dennis –

    Dennis, that video of SW-3 is not fantasy. Watch the fragments fall back and at the same time pull into a more lined up position behind the main body. I am not inventing anything. If you have a better description of what is there to see, give us your handle on it.

    Whatever forces they are, I assure you that since SW_3 DID exactly that, that the forces are empirical and not imaginary. Do I MYSELF understand it all? No. But calling the reality of what happened (look especially at the image from months later) “imaginary” and “fantasy” belies the evidence right in front of our eyes in the images and the video.

    My thinking on it is that when the breakup happens, parts drift off, in whatever direction. But then their mutual gravity pulls them back along the main track. Don’t forget that they DO have mutual gravitational force.

    WHY do they fall back? My speculation is that the dust exiting from the main body pushes backward.

    Note on SW-3 that none of the fragments seems to go forward of the main body. That should tell us something about the forces involved.

    I am going to guess that the passage through “empty” space is not really through a vacuum. We know about the solar wind. Perhaps it is that, just like it pushes back on a comet’s tail. (And is a tail really different from a breakup? I am not so sure it is.)

    So, one force (likely the solar wind) pushes them back, and the other force vectors pull them into one line (of least potential, I would guess).

    A couple of people here seem to be arguing that a break-up cannot happen in deep space, only during a close pass of a planet.

    I post the opening of agimarc’s linked article on SW-3:

    Comet Schwassmann-Wachmann 3 Disintegrates

    It is happening for “no apparent reasons”, scientists say, but the comet Schwassmann-Wachmann 3 has been rapidly breaking apart, provoking another round of second-guessing by astronomers.

    Buzzing around in deep space, SW-3 “just happened to” begin disintegrating. I am not inventing it or imagining it. It is clear from all visible evidence and available expert comments that that is exactly what happened. NO PLANET WAS INVOLVED.

    Yes, planets will make it happen, too. Probably a lot more often, too. But SW-3 is proof positive that this happens in deep space “for no apparent reason.”

  • Steve Garcia

    Dennis –

    You argue: “Yet we have overwhelming evidence of continental scale fires like you might expect if the Earth were to pass through a dense cloud of commetary debris.”

    From memory, I am certain I recall that the Earth has passed through comet’s tails in historical times, and – knowing that was going to occur – people freaked out, wondering what kind of plagues and disasters might befall us.

    But those disasters never happened. Especially not a conflagration.

    So, I am going to have to ask:

    What kind of density constitutes a “dense cloud of cometary debris”? Convince me on this. I am open to be convinced, but at this point I don’t see it as inevitable or even a high chance event.

    For one thing, nearly 100% of all matter that historically enters the atmosphere is micro-meteors, and all of them burn up VERY high in the topmost atmosphere. Having more of them doesn’t change the scenario for each individual; each one still ablates and vaporizes in the same way, irregardless of what is happening to others nearby. If anything, I’d suggest that having a few billion or trillion of them entering the atmosphere together, their mutual radiation would cause each other to ablate even faster (higher). Higher in any of these cases argues for less watts per meter at the surface.

    Even if it was a thousand of them like Chelyabinsk, I am not sure fires would be set with that many 15-meter objects airbursting at 25-km high.

    I heard a nice quote today: The default position for scientists is skepticism.

    I agree. I tend to spot the things that DISAGREE with some factoid in my head, rather than things I agree with at first glance.

    “Skeptical radar”?…LOL

    So when we challenge each other here, I hope we all grin and bear it as we tussle about these things. I take nothing personal and give out no personal attacks in what I say.

  • Steve Garcia

    Dennis again –

    “I also don’t get the cognitive need to believe that the YD impacts must have been the same kind of plop, plop, plop, one big chunk at a time, series of impacts we saw at Jupiter.”

    I ONLY bring that in as counter evidence of a “cloud” of fragments all hitting within one hour, as Bill Napier is quoted as saying.

    IF:
    1.) SL-9 was fragments hitting one at a time, and
    2.) SW-3 has lined itself up as a string of pearls,

    then we have to wonder if that is the norm or an aberration.

    “But what kind of geomorphology do we expect from 10,000 Tunguska’s?”

    Very good point. Neither Tunguska nor Chelyabinsk was large enough to change the geomorphology.

    What does that basically tell us? That something bigger than the bigger one (Tunguska) is necessary for geomorphology modification.

    What does it SUGGEST about multiples? That more trees would get knocked down, certainly.

    Does it suggest that conflagrations will be fired up? I recall nothing in the literature about Tunguska that any fire was started at all. If it was, I should remember it, but perhaps I didn’t see anyone make a big deal out of it, so I missed it.

    But could multiples cause a fire where a single airburst didn’t? IMHO there are too many variables – size, material density, angle, density of objects per square km, timing of the airbursts, and heights.

    As I stated above for micrometeors, I would think that Tunguska-sized multiples would simply ablate and vaporize like a single one would (no ‘boost’ given by nearby objects). At 23-km Chelyabinsk didn’t do much more than give some people sunburns. There is a big gap between sunburns and igniting forests.

    10,000 Tunguskas? There might be spots that ignite, but I wouldn’t bet on it. I mean, if they were collectively spread over a 100km x 100km area, that would be ONE Tunguska per sq km – which is a REALLY tight pattern of incoming objects. If over a 200km x 200km area, it would be ONE per 4 sq km. Tunguska’s area of trees knocked down was about 50km x 70km – and with rounded corners to its butterfly pattern.

    Igniting at 15 or 20 km high, would one spot on land be subject to the effects of more than one? Yep. Perhaps a few dozen. But would it be more than multiple mechanical impulses from the airbursts, as Tunguska and Chelyabinsk evinced? Right now that is where my head goes.

  • Steve Garcia

    Dennis –

    “But if you want to go looking for a way to show that very large airbursts have hit a given area in the past you might be on to something.”

    Your preceding points about new types of impacts are well taken.

    By “very large airbursts” I assume you mean each one is very large.

    Probably going over well-worn ground here, but the main thing going on with entries is ablation of the first 3mm or so (at a time), followed immediately by vaporization of the melted-off material (by the compressed>heated air in contact with the object). This melted material sloughs off as it melts, then flows back around the sides of the object, all the time heated until it vaporizes. ALL the material lost is lost in this manner,except when fractures are overwhelmed by the compressive force at the face of the object. In that case, chunks do fall off. That is (IMGO) what the 2 or 3 early flares were at Chelyabinsk.

    Each droplet sloughed off exposes a new spot on the front face of the object. Effectively, ALL of the stress is on that front face. The HEAT involved only penetrates a few cms – mostly on the face, but to some extent wrapping around the sides (where the heat is not magnified by compressive forces. The rest of the object is not heated much at all.

    It is NOT altogether different from watching an ice cream cone melt from an overhead Sun. The middle of the dip of ice cream is mostly insulated from the Sun and can stay relatively solid for a fair while.

    The bigger the object, the longer the object will last in the atmosphere – all other things being equal. Only when the overall size gets down to some threshold will the object disintegrate in what we call an airburst.

    All of this is to say that larger objects are more likely to impact the surface before airbursting – because they remain more resistant to disintegration, due to more mass and its corresponding greater cohesiveness.

    Yes, (all other things being equal again) larger objects are also more likely to make it lower into the atmosphere before disintegration (Dennis’ “very large airburst”) – but one has to think that it is a narrow window, of size and internal strength, between impacting and high airbursting. In other words, Boslaugh’s airburst scenario just above the ground is pretty much a fantasy. A Goldilocks airburst – not too big and not too high on one hand and not too big (impact) on the other.

    Frankly, after seeing Chelyabinsk, I came away convinced that an airburst is completely incapable of doing anything like the damage that had to have occurred at the YDB. My thinking since then has been that it HAD to be a surface impact ON the ice sheet. “On the ice sheet” because of the lack of a crater. And “surface impact” because the energy density on the ground at Chelyabinsk was far too low. As in <<< too low.

  • The separation of the fragments of SW3 is a simple break up. The thing that’s missing from that video is any visual indication of the directionality of the comet’s orbital path. But without the gravitational influence of a large planet, the only other force working on the fragments would have been the solar wind. And that would stretch things out in a line facing away from the sun. There is no known force that could make the fragments reorganize after separation into a line along the orbital path of the comet. But even if it did, and the Earth were to cross orbits with it, you still would not see all of the fragments falling into the same latitude on Earth like SL9 hitting Jupiter because the orbital path of the comet would be perpendicular to that of the Earth.

    But really, Jupiter’s mass is something like 317.83 times that of the Earth. And our best suspect for the YD impactor is debris from the breakup of the Taurid progenitor, which is estimated at 50, to 100 miles wide before it broke up. The ET materials in the black mat add up to enough that it led Firestone 2007 to propose something plowing into the Earth that was up to four miles wide before breaking up.

    The orbital mechanics, and behavior of SL9 during its encounter with Jupiter bares no resemblance whatsoever to that of either Linear, or SW3; much less any realistic interaction between a comet, and the Earth’s gravity.

    Bottom line: The relative masses are all wrong, so wrong that using the interactions between Jupiter, and SL9 as a model for any kind of Earth based impact event is an exercise in rediculousness, and right up there with studying the behavior of elephants in order to predict the mating habbits of a mouse.

  • Steve Garcia

    Dennis –

    …the fragments began falling back towards Jupiter in a capture orbit, then all of the fragments were falling towards the very same point relative to Jupiter’s center of gravity. So they all hit exactly the same latitude, but at different longitudes as the planet rotated beneath.

    Yes, it seems you agree with me on these points. Thanks. I appreciate your concurrence.

    If that orbit crosses that of the Earth then we have the potential for a celestial train wreck at the crossing point with one or more of the fragments. But since they would not be falling towards the Earth’s CG in a capture orbit, it’d just be a simple traffic jam. So if more than one hit, they’d be all over the place.

    VERY GOOD OBSERVATION/ANALYSIS.

    NON-CAPTURED OBJECTS
    If NOT captured in Earth’s gravity well, it is like vehicles speeding through an intersection on cross streets.

    At 20 km/sec the Earth travels 72,000 km/hour. If the first fragment hit us, then with a planetary diameter of 12,742 km, that means in ~10.6 minutes the Earth is past the intersecting point on its orbital path. If the next object came along after about 11 minutes, it and subsequent “pearls” should fail to hit us.

    CAPTURED OBJECTS
    As we saw with SL-9, the comet WAS captured on the last previous pass of Jupiter. In talking about a captured object and Earth, then, it is absolutely required that the capture be made on a previous pass (likely the last pass, but perhaps not). Otherwise a string-of-pearls train-wreck cannot happen.

    VERY GOOD THINKING, DENNIS.

  • It is important to note that in the case of either Tunguska, or Chelybinsk neither of them were big enough for the fireball to actually reach the ground. Tunguska represents a sort of threshold where the heat of the fireball almost made it to the ground. But not quite. So the only heat effects we see there are those produced by the IR pulse. And if the simulations done at Sandia labs are to be taken seriously then a comet fragment that’s not very much larger than whatever hit Tunguska should be big enough to produce a fireball that’s able to reach all the way to the ground with temps hot enough to melt silicate rocks. Couple that with sustained supersonic surface winds at the point of impact for twenty seconds or so and you have the potential for some damned efficient stripping, and ablation of the melted material. Once ablated, and in the wind, the particles of melt would become those cute little nano diamond studded spherules.

    But if all, or most of the melted material in an ablative event get’s blown away like that, then what what do we expect the places the material in those spherules came from to look like after almost 13,000 years of fairly normal climate, and weathering?

    The Libyan Desert Glass is the only known example of an ablative airburst at that scale. And the geomorphology of that place has no resemblance at all to an impact crater.

    The Clube & Napier discription of the Earth’s probable encounters with debris from the breakup of the Taurid Progenitor is a senario that should have included dozens, if not hundreds of ablative airbursts like that during that hour or so of hell on Earth. And since there is a strong probability that none of them would have presented the standard set of kinetic impact markers like shocked quartz grains, there is a strong possibility that the planetary scarring of the YD impacts has been right under our noses all along, but has been mistakenly interpreted as volcanogenic.

  • Steve Garcia

    Like most people, at first I was impressed with Sandia’s modeling. As I’ve learned more and more, I’ve come to see that as pretty programming and almost nothing more. Bos could put in whatever parameters he chose. GIGO.

    A lot of it has to do with my realization that there is nothing inside the object that is explosive, per se. The airburst is only the disintegration of the remaining object, from pressures and shocks, due to the air resistance and its high temps. The flaring is the ablation and vaporization – and when the internal structure fails, much more surface area is exposed, thus making it look like the object exploded. Now, an explosion is defined as a very rapid expansion, so in THAT case it is an explosion, because vaporization at those temps IS a rapid expansion. No doubt about that. That is why Chelyabinsk had the shock wave from the disintegration. And Tunguska, certainly.

    But I challenge Bos’ plasma, blah, blah, blah. Regardless at which height it occurs, the BOOM in it all is simply vaporization of the ablated materials. And that vaporization WILL BE an energetic expansion. But it will no more be plasma than it was all along its path in the atmosphere. It will just be more material being vaporized and, if it is close to the ground as he chooses for his model, then the reflection will certainly create more chaotic core conditions. That reflection will drive the energy vertically, like any airburst near the ground of any explosive device. But it is hard to see it becoming plasma any more than it is for higher airbursts.

    The odds on that object in his model going THAT fast and airbursting THAT close to the surface are really, really small. IMHO, his model is a cherry-picked model run that happened to make the prettiest image and help make him a poster boy for airbursts.

    In addition, HIS airburst model for the LDG is only one of several hypotheses. It is not even close to a proven fact. The way he cherry-picks his airburst height, for example, only goes to show that whatever parameters he builds from, we need to be skeptical of the tale he tells.

    In terms of all this reflecting on your desert melt, Dennis, I think you are on more solid ground than Bos is. At the same time, I keep an open mind on it all perhaps being from a very low angle pass, with the vaporized materials in the tail of the object melting hilltops that it passed over very low. As I’ve said before (long ago), if the hills were airbursted, the flare-up (vapor expansion) would have easily gone all the way down to the base of the hills and onto the flat surface around the hills. I think your idea is very close, but because I don’t see melt on the flat areas, an airburst seems unlikely. From what I see.

    As an example, Chelyabinsk airburst at about 25 km, and even from that height the shock wave broke all those windows and gave a few sunburns. If that airburst had been at 1,000 feet (about 0.6 km), the shock would have been magnitudes more intense, and the infrared equally greater. Yes, the infrared would have hit first, and then the shock wave could have pushed the melt downward. But had it been that low, the bottoms of the hills and the flat area would also see melt. I’ve mentioned this before.

    Your hills seem definitely ET. The details I am guessing at and voicing my guesses.

  • Steve Garcia

    George: “Equally obvious to me (perhaps not the kids) is the conspicuous absence of any citation to the Firestone papers. It would seem that multiple major journal publications providing much more detailed evidence of frightful temperatures and horrendous fires within the period of Marin-Spiotta et al.’s own study of the same region would merit a reference in support of their hypothesis.”

    In reading the paper, George, I got the impression it was done by biologists for biologists and with no conception of even geology. Even though their main thrust was “Holy crap, Batman!! Who would have thought there was that much carbon sequestered under the ground!” In that vein it is almost a climatologist paper.

    Their sampling was even worse than Surovell, because they didn’t seem to care how precise their dates were, nor did they clearly define where the samples were really from – bottom, middle, top of the Brady soil. They did measure the depth, but did not refer it to the Brady soil at that specific spot. The Brady soil’s distance to the surface varies, so this matters. Also, they seemed to take wide swaths of dirt instead of narrow slices. So who KNOWS what their dates mean? I don’t think they do.

    But I do think it would be an area that the YDB folks would want to go and take more precise samples of.

  • Steve said:

    But I challenge Bos’ plasma, blah, blah, blah. Regardless at which height it occurs, the BOOM in it all is simply vaporization of the ablated materials. And that vaporization WILL BE an energetic expansion. But it will no more be plasma than it was all along its path in the atmosphere.

    Hmmm…

    Most folks learned about the so called three states of matter, i.e. solid, liquid, gas in high school. But in fact, plasma is matter’s fourth state.

    For our purposes here we can define a thermal plasma as any material that’s hot enough that the electrons have been stripped from the nuclei; all the extra free electrons making it electro-conductive. In fact, if you get any material hot enough you can turn it into a superconducting plasma. But we are talking about temps hotter than the surface of  the sun here. With the exception of exceptionally large impacts, in any given impact event those conditions only exist very high in the atmosphere at the beginning of atmospheric entry.

    The superconducting plasma phase of a large impact event is where we get the infamous EM pulse. But so much energy is quickly lost to infrared radiation that by the time the IR pulse has finished, the plasma has cooled well below the free electron state and is nothing more than extremely hot incandescent gasses.   

    It will just be more material being vaporized and, if it is close to the ground as he chooses for his model, then the reflection will certainly create more chaotic core conditions. That reflection will drive the energy vertically, like any airburst near the ground of any explosive device. But it is hard to see it becoming plasma any more than it is for higher airbursts.

    Point of fact. Boslough never said plasma conditions exist near the ground during an airburst. In fact, in conversations with him on the subject, and for the reasons given above, he tends to downplay the significance of plasma conditions in an impact; they’re too transient.

    The odds on that object in his model going THAT fast and airbursting THAT close to the surface are really, really small. IMHO, his model is a cherry-picked model run that happened to make the prettiest image and help make him a poster boy for airbursts.

    Since comets can come at us at speeds of up to 70 km/s then 20 km/s is a pretty modest estimate. And Mark didn’t “chose” the height of the airburst. It was calculated for him based on the theoretical object’s size, composition, and speed, by the computer running the simulation

    But really, I think it’s time to take issue with ad hominem cheap shots. They have no place here. And no matter how well regarded a Physicist is, no one gets to use the supercomputing capabilities, and assets of a major national laboratory just to make himself look pretty. But when did you calculate the “odds” you speak of, and whose data did you use to do it? Or are you just working from a wild, hairy-assed, guess yourself?

    As someone who’s been working for Uncle Sam as a research Physicist at Sandia Lab for something like 30 years, or more. Those sims came about as a result of Mark’s ongoing work on the Tunguska event. He went there personally first to see the place for himself, and to collect his own independent data, and samples He then took everything he had learned there and wrote up a model to run in  Sandia’s Red Storm supercomputer to test the data he’d collected. That run produced some pretty darn good sims that are extremely consistent with what we actually see on the ground there today.

    That hydrocode model, which was based on a carbonaceous chondrite coming in at about 20km/s was so successful at describing a known event like Tunguska he decided to test it on the LDG to get some kind of scaling of airburst events. So you get a series of model runs with different impact angles, and progressively larger impactors until he got something consistent with what he found on the ground there.

    That ain’t cherry pickin’.

    Imagine that! A scientist who’s not afraid to get out of his lab, go half way around the world, and turn over a rock or two to dig up his own independent data

    In addition, HIS airburst model for the LDG is only one of several hypotheses. It is not even close to a proven fact. The way he cherry-picks his airburst height, for example, only goes to show that whatever parameters he builds from, we need to be skeptical of the tale he tells.

    Really? Those sims only provide animated illustration to peer reviewed, and published works. Have you ever really bothered to read anything Boslough has published on the subject? Or are all of your opinions of his work based solely on those cartoons, and what folks had to say about them? And if there are several competing hypotheses for the creation of the LDG whose are they? Have they ever been on the ground there? And where did they publish?

    And as I said, the height of an airburst in those sims is calculated by the supercomputer running them. It’s not one of the variables you enter before a run. If it were, then it would not be a valid scientific model, just a good animation.

    Mark’s got a bad rap around these parts because he’s our favorite hypothesis’s most outspoken, and prominent skeptic. And I’m not someone who’s running around trying to drum up support for a Mark Boslough fan club here; on a personal level, sometimes he can be downright disingenuous if he has a low opinion of something. The YDIH for example. But anyone who’s ever took a good look at his CV, and actually read his peer reviewed works will tell you that as a physicist, and skeptical scientist, his work, and the science he does, is bordering on impeccable. After all he’s his own most skeptical critic.

    Bottom line: We don’t do good science by empty hand waving, ad hominem put-downs and tossing out the works, and opinions, of good skeptical scientists we are displeased with just because they are unsupportive of our ideas. We do good science by answering all their objections with solid, irrefutable, data, and convincing them.

  • Steve Garcia

    Dennis – Hold on, Dude. I am on your side. But let me start with a simple answer to one of the questions.

    It doesn’t matter whether you (or I) agree with any particular one, or think that one is dumb. They are what they are.

    I had said: “HIS airburst model for the LDG is only one of several hypotheses.

    And if there are several competing hypotheses for the creation of the LDG whose are they?

    From a skeptical science blog at http://www.skepticreport.com/sr/?p=288, there is this:

    Over the years, many theories have been put forth explaining the origin of Libyan desert glass. Researchers have proposed that the glass formed at the bottom of a giant volcanic lake, formed as the result of a meteorite impact, and formed because of the detonation of an ancient atomic bomb built by aliens.

    Hang on a minute. Let’s play a quick game of which explanation doesn’t belong. Or, to put it another way, let’s find the woo-woo speak. I’m going with the aliens and the ancient atomic bomb. What’s your choice?

    So, let’s leave out the ancient atomic bomb idea favored by my friend David Hatcher Childress (named a paragraph or so later). That leaves at least THREE hypothesis, just from that one source. (semi-source if you choose to insist…)
    1.) Bos’ low airburst of
    2.) Meteor impact
    3.) Formed at the bottom of an ancient volcanic lake – Sediment-hypothesis [JUX, 1983]
    4.) Hydrovolcanic processes [http://www.b14643.de/Sahara/LDG/]

    Add to those:
    4.) “It seemed easier to assume that it had simply fallen from the sky!” [Clayton P.A., Spencer L.J. (1934) Mineral Mag 23:501-508]
    5.) Tektites
    6.) Hydrovolcanic Hypothesis [FELLER, 1996]
    7.) Comet impact [http://www.sciencedirect.com/science/article/pii/S0012821X13004998]

  • The altitude an object begins to vaporize, or explode in the atmoshere is product of the atmosphere, the speed of the object, and it’s density. Momentum is retained. And since the speed of the explosion in an air bursting meteor is just about equal to the speed of the decent of the thing, you don’t get a point detonation at a specific altitude. Instead, the explosion gets stretched out along the entire path of the object; the bigger the meteor, the deeper its fireball penetrates into the atmosphere before there is nothing left of it but a shockwave.

    In the scaling of airbursts, there is a threshold where the object is big enough that the fireball it produces reaches all the way to the ground with temps hot enough to melt silicate rocks. Anything smaller, and the only effects at ground level are a quick flash of intense IR, followed by the shockwave.

    Tunguska can be thought of as the point where you get significate damage at ground level from the heat of the IR pulse and shock wave, but none of the heat of the fireball makes it to the ground with temps that can melt rock. Yet anything bigger would.

    The LDG can be thought of as a place where it did. And since volcanism has been ruled out there as the thing that melted the sands of the Sahara, and since there is no impact crater there…

    I have no time for old science on the place, and I won’t even give pseudoscience a read. I am inclined though to trust recent science if it’s done by or under the auspices of a major National Lab. You see? It’s not just one lonesome physicist whose reputation is on the line if Boslough’s work in Libya doesn’t hold up; but Sandia’s too.

  • Steve Garcia

    Dennis –

    Boslough’s thing is just one hypothesis.

    None of those hypotheses seem to have been ruled out. Yes, Bos thinks his is right – which in his mind makes all others wrong. So what?

    Asserting that Tunguska is itself the threshold of when an object is a Goldilocks size is not justified. Asserting that the LDG event is in your mind both ONLY possible as a meteor (comet?) AND just the other side of that threshold is only your opinion, and you are entitled to that opinion. Your thoughts are taken into consideration and respected, but at the same time that doesn’t mean they are the correct explanation. I don’t happen to agree with your delineations of it, though. Some of it seems correct, while some of what you conclude it I don’t agree with.

    Let’s agree to disagree. I hold my assessments and you yours. It won’t be the last time we disagree… 🙂

    As to work done by a guy at a national lab, Richard Muller over at Lawrence Berkeley Labs came up with the silly Nemesis dark star theory and embarrassed himself with it. So, you see, simply having gotten signed on to a national lab does not ensure solid science. And when they make mistakes, how are we to know which are mistakes and which aren’t? Man crushes aside, the work stands or falls on its own merits.

    “The default position of science is skepticism.”

    I have seen lots of ideas in science that sounded reasonable but ended up not being correct. Boslough’s idea sounds reasonable, and he does make pretty models. But models are not reality – only representations of reality, based on SOME assumptions that SEEM reasonable. There are other scientists who disagree with his explanation, so why can I not disagree also? Does he get a gold star merely by being employed at Sandia? (…Which is a bit down the prestige list as far as national labs go, I might add. THAT I learned from a friend who worked for years at Los Alamos, right down the road from Sandia. All national labs are not equal. Lawrence Berkeley is way up the list, and yet, there is Muller, coming up with Nemesis – the single silliest idea I’ve heard in astronomy in all my born days.)

  • Steve Garcia

    Re Boslough, I am reading one of his papers, one that basically says we shouldn’t be worrying about mitigation as much as we are about civil defense kind of ways, of dealing with the calamity if it or when it comes.

    http://fallmeeting.agu.org/2013/files/2013/12/Boslough-airburst-acta-2013.pdf

    Abstract

    It is virtually certain (probability >99%) that the next destructive NEO event will be an
    airburst. Planetary defense is usually assumed to have the primary goal of maximizing the
    number of lives saved, but it can be argued that more emphasis should be placed on
    maximizing the probability of saving lives. For the latter goal, it is far more effective to
    create an early warning and civil defense plan than a mitigation plan that involves
    deflecting a large NEO. Because early warning and civil defense will almost certainly be
    needed long before the first deflection is ever required, the credibility of the planetary
    defense community and its recommendations will be put to its first serious test by an
    airburst. Successful response to an airburst event will make it much more likely that
    recommendations for mitigation by deflection will be accepted by decision makers and
    the public. Focusing more attention on the second goal will, as a side effect, benefit the
    primary goal.

    His opening abstract line I already disagree with. He is talking about “destructive” events. I guess by “destructive” he includes fist-sized meteorites that hit cars and houses, so >99% is certainly right. If he is referring to ones we need to – or CAN – do anything about Chelyabinsk is a good place to start.

    And we know that the Bos just wrote that last MAy simply to piggy-back on the attention that Chelyabinsk brought to the issue of mitigation. And he just HAD to be a nay-sayer to what everyone ELSE was saying at the time: MITIGATION PLANS. So he could look cleverer than everyone else, he put a twist on it and argued for, “Let’s just get ready to deal with all the dead bodies.” He didn’t want to be drowned in the cacaphony of “HEY! Let’s try to save lives!” In fact, he specifically said so:

    Planetary defense is usually assumed to have the primary goal of maximizing the number of lives saved, but it can be argued that more emphasis should be placed on maximizing the probability of saving lives. For the latter goal, it is far more effective to create an early warning and civil defense plan than a mitigation plan that involves deflecting a large NEO.

    I don’t know if it is possible to disagree more with him. Not that one is sexier than the other. It is that if a BIG one is coming, it isn’t going to BE a local event.

    On another front, his Figure 2 shows exactly what I was criticizing – his magical airburst just a few meters off the ground. THAT scenario is rdiciulous, that THAT close of an airburst cna happen. He claims >99% airbursts over impacts. I claim his low LDG airburst (his label, not mine) is absurdly improbable.

    Why do I say that?

    Well, if he NEEDS that close of an airburst, then where are the fragments? To get that low the object needs to be larger than Tunguska, yet a larger object airbursting is going to have at LEAST ONE fragment (and certainly bigger ones) as big as Chelyabinsk’s 300 kg main body. If so, where is the LDG main body?

    Even one as big as Chelyabinsk is going to have fragments that can be found. But those don’t exist in the LDG area.

    And one big enough to penetrate nearly to the surface would have basically ZIP chance to airburst at his magical height without having already airburst – or hitting the surface. His window of “success” is basically silly season. His model showed different angles and different heights, and ONE run of those magically gave him the results he wanted, so he chose it.

    He can’t have both a bigger body and NO fragments large enough to find in the LDG strewn field. Even a Chelyabinsk-sized object would give him SOME fragments on the ground.

    I call it a magical height because with the object traveling at at least 10 km/sec, the object is in that position for only a microsecond or so. (Much slower and there would not be enough velocity to cause the airburst.) Either it airburst higher, or it would have hit the ground. THAT position (height) is a figment of his imagination. YES, the model shows it happening. But try to get a real meteor to airburst that low – and at no other height. Not going to happen.

    And THEN to have no fragment meteorites? Again, not going to happen.

    Re cherry picking:

    In industrial R&D we would run matrixes of two variables to see what resulted. It was a VERY successful strategy. That way we were able to assess later observations against the matrix parameters. In some ways that is similar to what Bos did, because he ran a lot of model runs with variable values for weight, density, angle, etc. But there is one one big difference: Ours were REAL empirical, physical results, not model outputs. And we also weren’t looking for one success out scores of matrix combinations. We lived with whatever the test results showed, so when later real-world runs showed problems we could see what variable had gone haywire – as a starting point to speed up trouble-shooting.

    Models simply are NOT reality. Not unless ALL the parameters are well known and tested.

    Using models to simulate hypothetical conditions can help the thinking process, but to present model outputs in such a hypothetical as real, that really is not science.

    It is the Bos’ strong suit, modeling, so he has to continually present pretty pictures in order to keep funding rolling in. And he DOES need to market himself. My friend who worked at Los Alamos (and whose husband was the top laser scientist there) talked about how the national labs have to vie for contracts all the time. Funding from the government is WAY down, and they have to work to find funding elsewhere. Being a national lab, Sandia and Los Alamos have a leg up on some of their competitors, but that doesn’t guarantee squat. One can consider most if not all of his public attention grabbing as sales pitches.

    I respect that the Bos has to market himself. It is part of reality in the 21st century world of science. But I simply don’t think that models in frontier areas of science are reliable science.

    His pimping his work about airbursts all the time I understand – he has to frame everything in a way that keeps him in the limelight. But I would never rely on his work as anything more than hypotheses to be further tested in the new world – except testing incoming meteors and comets is impossible.

  • Nice Op-Ed Steve.

    It’s chock full of highly creative and imaginative word salad, and ad hominem stuff attacking the way science is funded, and done at National Labs. I’m sure Fox News would love to hear from you. Too bad you didn’t flesh it out by giving us some links to honest to-somebody-actually-did-some-real-science technical data, or peer reviewed rebuttals to the above paper to support your vociferous objections and assertions.

    By the way, would you mind telling us again where you studied impact physics?

  • Steve Garcia

    Dennis –

    You’d asked before who had alternative hypotheses for the LDG, and I provided several.

    You yourself don’t provide links to everything you say, so it shouldn’t be incumbent on me to do so.

    I did not do an ad hominem attack on anybody, except perhaps the Bos. I explained, for those who were not aware of it, that the national labs are not even close to being fully finded by the US government anymore, so the researchers in all their departments do need to go out and drum up work. I gave a source – a friend of mine who used to work there for years, along with her ex. Telling people this is in no way an ad hominem attack.

    It’s clear that you like Boslough, and that I don’t think his work is as special as some do. It’s not necessary for me to meet your standards as to links when I take exception to his work. I have the right to have an opinion and to set my own standards. I source when I have one, and I am darned sure that I make it clear when it is my opinion. When I disagree with his cherry picking of that height, that is not an ad hominem attack, and I beleive I spelled out clearly why I think it is cherry picked. That miracle height just above the ground is not defensible, since it was at that height for such a short instant of time, traveling as fast as it would have been. Yes, IF – a very big IF – it “exploded” (as he calls it) at just that height, he would get something close to what his model shows – except that where are the fragments of the very large body in the LDG desert?

    I am allowed to ask such questions and to have an opinion about Boslough’s work, just as you are.

  • Steve Garcia

    And where did you study impact physics, that you have an opinion, too?

    Sorry, but calculating how long a moving body approaching the ground is within a particular height window is not impact physics.

    Asking where the fragments went to is also not impact physics. Chelyabinsk, much smaller than Bos’ proposed object, had fragments in a strewn field, plus a main body that was found. It is a fair question to ask why a larger body would airburst similarly and not have fragments lying on the desert floor like Chelyabinsk had fragments lying on the snow. One does not need to know impact physics to ask such a question.

  • Steve –

    Much food for thought in the discussion. A possible explanation for a distribution of comet fragments in a line (from our perspective) or more likely in a plane would be tied to the rotation rate of the comet itself. Once it comes apart, my guess would be due to the action of differential heating of ices inside it, which also provide a propulsive impulse, the rotational energy of the body will be carried away by the chunks as they depart. For a simplified version, think of a flywheel coming apart at speed or a turbine section breaking apart during flight. An irregular body should be a lot more complex as it should be rotating (or tumbling) far slower and as pieces start breaking off, it redistributes the mass and changes the rotational axes.

    There is an effect called the YORP Effect by which sunlight shining on asteroids will change their rotation rates and occasionally even their orbits. It is thought to be significant enough to spin smaller objects to the point that they disrupt.

    http://www.space.com/5605-sunlight-splits-asteroids-pairs.html

    The problem with this is that new comets are not in the inner solar system long enough for this effect to be significant unless they have been captured into orbits that keep them around for a while. Still a lot to learn. Cheers –

  • It’s not that I’m a fan of Boslough Steve. But rather, that I have an extremely low opinion, and patience thresholdof the use of ad hominem comments, and arguments that go to the person, or organization, rather than heart of a debate. The use of such comments are a glaring logical falacy. And they never, ever, no matter the subject, or expertise of the speaker, contribute anything inteligent to a conversation, or debate.

  • Steve Garcia

    Dennis –

    You keep on saying “ad hominem” but you haven’t once pointed at one specific case.

    Ad hominem:
    …1. appealing to one’s prejudices, emotions, or special interests rather than to one’s intellect or reason.
    …2. attacking an opponent’s character rather than answering his argument.

    (Yes, ad hominem is a form of logical fallacy. In that you are correct. But where did I do that? You didn’t say in the first place and haven’t said since.)

    A. Saying that I think the height is cherry picked is not. Cherry picking is a form of fraud in science, and wherever it is found needs to be exposed.

    B. Saying that models are not reality is not. Models are 100% dependent on the computer code that runs them and the assumptions that the code is based on. In this new world of science via computer, it sis necessary – nay, required – by journals to submit suich code, so that others may verify that the code was written properly. The methodology must necessarily be presented in order that the assumptions and methods may be seen as appropriate and well-founded. When one writes one’s own code and thus makes one’s own models it is completely possible that that one person is the only person that knows what is going on – and that is a state that needs to be able to some day be checked for accuracy.

    And when an object descending toward the Earth’s surface is said to be the ONLY case of many runs, has the individual presented the full OTHER cases. Has the individual actually presented all the arguments and counter arguments for all to see? These are questions of the science and its application, not attacks upon the person, though the challenge may be SEEN to be. But it is not. It is part of the skepticism that is science: “Sir, did your logic leave anything out? Did it have anything superfluous? Are your assumptions defendable? Is your methodology replicatable? Did your code get written properly? Are your constants correct and applicable? Does your code actually do what you claim?”

    Models are ONLY able to be replicated if the code is made public so that it can be run again. On the frontiers of science new formulas are brought up and they must stand the test of reality, called empirical experimentation. Computer runs are NOT experimentation, nor are they by themselves necessarily representative of the science being pursued.

    C. Saying that scientists have to draw attention to themselves to garner funding? Is that ad hominem? I don’t THINK so. I think it is fair for everyone to have knowledge of how the system works at this time. The few scientists who get themselves noticed by the news media do not need to be treated with kid gloves; they have enough advantage from that to stand up for themselves.

    D. Saying that others have alternative hypotheses (which I’d like to hear your response to – and WHY I posted that in the first place) – that certainly isn’t ad hominem.

    I COULD bring up something Bos did HERE, but I promised along time ago that I wouldn’t so I never have.

    But the main thing here is that I’ve brought up several science points that all you do is ask me if I am an impact scientist. Is THAT not ad hominem in itself? Implying that my person is not qualified and that therefore all my questions and arguments must be inferior?

    Please be specific when saying I am using ad hominem attacks. It is impossible to rebut vague accusations.

  • From Wikipedia:

    An ad hominem (Latin for "to the man" or "to the person"), short for argumentum ad hominem, is a general category of fallacies in which a claim or argument is rejected on the basis of some irrelevant fact about the author of or the person presenting the claim or argument. Fallacious Ad hominem reasoning is normally categorized as an informal fallacy, more precisely as a genetic fallacy, a subcategory of fallacies of irrelevance. Ad hominem reasoning is not always fallacious, for example, when it relates to the credibility of statements of fact.

    Steve said:

    “Re Boslough, I am reading one of his papers, one that basically says we shouldn’t be worrying about mitigation as much as we are about civil defense kind of ways, of dealing with the calamity if it or when it comes.”

    Airburst Warning and Response ~Mark Boslough

    Abstract:

    It is virtually certain (probability >99%) that the next destructive NEO event will be an
    airburst. Planetary defense is usually assumed to have the primary goal of maximizing the

    number of lives saved, but it can be argued that more emphasis should be placed on

    maximizing the probability of saving lives. For the latter goal, it is far more effective to

    create an early warning and civil defense plan than a mitigation plan that involves

    deflecting a large NEO. Because early warning and civil defense will almost certainly be

    needed long before the first deflection is ever required, the credibility of the planetary

    defense community and its recommendations will be put to its first serious test by an

    airburst. Successful response to an airburst event will make it much more likely that

    recommendations for mitigation by deflection will be accepted by decision makers and

    the public. Focusing more attention on the second goal will, as a side effect, benefit the

    primary goal.

    “His opening abstract line I already disagree with. He is talking about “destructive” events. I guess by “destructive” he includes fist-sized meteorites that hit cars and houses, so >99% is certainly right. If he is referring to ones we need to – or CAN – do anything about Chelyabinsk is a good place to start.”

    Objection: Assuming a definition for the meaning of “destructive” beyond the simple definition given in Webster’s Dictionary is not warranted, or implied, anywhere in the abstract, or the rest of the paper for that matter. So that part’s pretty much irrelevant.

    “And we know that the Bos just wrote that last MAy simply to piggy-back on the attention that Chelyabinsk brought to the issue of mitigation. And he just HAD to be a nay-sayer to what everyone ELSE was saying at the time: MITIGATION PLANS. So he could look cleverer than everyone else, he put a twist on it and argued for, “Let’s just get ready to deal with all the dead bodies.” He didn’t want to be drowned in the cacaphony of “HEY! Let’s try to save lives!”

    And that boys, and girls, is a textbook example of ad hominem circumstantial.

    Again from Wiki:

    Ad hominem circumstantial points out that someone is in circumstances such that they are disposed to take a particular position. Ad hominem circumstantial constitutes an attack on the bias of a source. This is fallacious because a disposition to make a certain argument does not make the argument false; this overlaps with the genetic fallacy (an argument that a claim is incorrect due to its source).

    “In fact, he specifically said so:”

    Planetary defense is usually assumed to have the primary goal of maximizing the number of lives saved, but it can be argued that more emphasis should be placed on maximizing the probability of saving lives. For the latter goal, it is far more effective to create an early warning and civil defense plan than a mitigation plan that involves deflecting a large NEO.

    “I don’t know if it is possible to disagree more with him. Not that one is sexier than the other. It is that if a BIG one is coming, it isn’t going to BE a local event.”

    Point of fact: There is nothing in this abstract or paper that states, or implies that the next large impact WILL be a local event.

    “On another front, his Figure 2 shows exactly what I was criticizing – his magical airburst just a few meters off the ground. THAT scenario is ridiculous, that THAT close of an airburst can happen. He claims >99% airbursts over impacts. I claim his low LDG airburst (his label, not mine) is absurdly improbable.”

    This assumptive proclamation won’t fly either. You’re welcome to your opinion. But to be clear, the data, graphs, charts, and illustrations in the paper, are all based on well described math, and formulae. Dr. Boslough went to the places, he studied, independently collected his own data and specimens, analyzed them, did the math, and ran the numbers in exquisite detail.

    I wonder, how much honest to somebody-check-me-on-this science can a man get done do from the comfort of his own living room?

    I’m afraid real science done by someone who’s actually gone out into the field turned over some rocks, collected some real data, and ran the numbers, trumps the unsupported proclamations, assumptions, personal objections, and cognitive bias of an armchair theorist every time.

    Why do I say that?

    Well, if he NEEDS that close of an airburst, then where are the fragments? To get that low the object needs to be larger than Tunguska, yet a larger object airbursting is going to have at LEAST ONE fragment (and certainly bigger ones) as big as Chelyabinsk’s 300 kg main body. If so, where is the LDG main body? Even one as big as Chelyabinsk is going to have fragments that can be found. But those don’t exist in the LDG area”.

    You’re assuming a specific composition/structural integrity that hasn’t been described. But I wonder how many large fragments of icy bodies such as a typical comet fragment might disappear without leaving any trace on the ground beyond fire damage, and strange, enigmatic geomorphology.

    “And one big enough to penetrate nearly to the surface would have basically ZIP chance to airburst at his magical height without having already airburst – or hitting the surface. His window of “success” is basically silly season. His model showed different angles and different heights, and ONE run of those magically gave him the results he wanted, so he chose it.”

    A wide range of conditions, and combinations such as impact angle, velocity, and bolide composition, were simulated to provide some clue as to the scaling of airbursts. Now since Dr. Boslough has actually been on the ground there accompanied by numerous geologists who helped to produce an updated geological survey the LDG, and since every one of those sims can be accessed online at the Sandia website, then pointing out the one that’s the most consistent with the geomorphology they found in Libya doesn’t fit the definition of “Cherry Picking”

    “He can’t have both a bigger body and NO fragments large enough to find in the LDG strewn field. Even a Chelyabinsk-sized object would give him SOME fragments on the ground.”

    Yeah, that unsupported assumption might fly if someone, sometime since 1908 had ever found a fragment of the Tunguska object. This in spite of the fact that it was much bigger than Chelyabinsk, and the fact that countless people have searched for it for more than a century. 

    “I call it a magical height because with the object traveling at at least 10 km/sec, the object is in that position for only a microsecond or so. (Much slower and there would not be enough velocity to cause the airburst.) Either it airburst higher, or it would have hit the ground. THAT position (height) is a figment of his imagination. YES, the model shows it happening. But try to get a real meteor to airburst that low – and at no other height. Not going to happen.”

    Really? Perhaps you would be so kind as to share with us the math, and formulae you so diligently worked through to come to such an authoritative proclamation of fact. And if that’s not available I wonder how many of those “real meteors” you’ve witnessed, or dropped from space.

    Unfortunately you speak of “THAT position” as if it were a point detonation at a specific altitude like a common nuclear explosion of a falling bomb. And since we know that the velocity, and downward momentum is retained during the explosion of a meteor, nothing could be further from what’s described in the paper, or by any of those sims.

    “And THEN to have no fragment meteorites? Again, not going to happen.”

    That one’s already been addressed.

    Re cherry picking:

    In industrial R&D we would run matrixes of two variables to see what resulted. It was a VERY successful strategy. That way we were able to assess later observations against the matrix parameters. In some ways that is similar to what Bos did, because he ran a lot of model runs with variable values for weight, density, angle, etc. But there is one one big difference: Ours were REAL empirical, physical results, not model outputs. And we also weren’t looking for one success out scores of matrix combinations. We lived with whatever the test results showed, so when later real-world runs showed problems we could see what variable had gone haywire – as a starting point to speed up trouble-shooting.

    Yeah, we’ve already covered the cherry pickin’ thing too.

    Models simply are NOT reality. Not unless ALL the parameters are well known and tested.

    Using models to simulate hypothetical conditions can help the thinking process, but to present model outputs in such a hypothetical as real, that really is not science.

    This is a straw man argument because it never really happened.

    Point of fact: There has never been a time, in any of Boslough’s work, or talks, on the subject when any those sims have been presented as anything more than a model, and compelling simulation of what he believes probably happens during an airburst event.

    “It is the Bos’ strong suit, modeling, so he has to continually present pretty pictures in order to keep funding rolling in. And he DOES need to market himself. My friend who worked at Los Alamos (and whose husband was the top laser scientist there) talked about how the national labs have to vie for contracts all the time. Funding from the government is WAY down, and they have to work to find funding elsewhere. Being a national lab, Sandia and Los Alamos have a leg up on some of their competitors, but that doesn’t guarantee squat. One can consider most if not all of his public attention grabbing as sales pitches.

    I respect that the Bos has to market himself. It is part of reality in the 21st century world of science. But I simply don’t think that models in frontier areas of science are reliable science.

    His pimping his work about airbursts all the time I understand – he has to frame everything in a way that keeps him in the limelight. But I would never rely on his work as anything more than hypotheses to be further tested in the new world – except testing incoming meteors and comets is impossible.”

    And finally, these last three paragraphs are where you capped off your rant with another irrelevant textbook example of ad hominem circumstantial.

  • Steve Garcia

    In terms of alternate hypotheses for the LDG…

    Bos is not the last word on this, obviously, since this 2013 paper goers in a completely different direction and calls the LDG a comet impact. “We propose that the stone is a fragment of a comet nucleus, shocked on impact.” What stone?

    See http://www.sciencedirect.com/science/article/pii/S0012821X13004998

    “• A carbonaceous stone found in the Libyan Desert Glass strewnfield was studied.
    • It contains sub-micrometer diamonds in an amorphous, carbon-dominated matrix.
    • Carbon isotope data (δ13C∼0) do not fit terrestrial coal or carbonaceous chondrites.
    • Argon, Kr and Xe isotope data show extraterrestrial origin different from chondrites.”

    Airbursts do not create shocked imactities, do they?

  • Steve Garcia

    Dennis –

    Point #1: I said: “Re Boslough, I am reading one of his papers, one that basically says we shouldn’t be worrying about mitigation as much as we are about civil defense kind of ways, of dealing with the calamity if it or when it comes…

    …His opening abstract line I already disagree with. He is talking about “destructive” events. I guess by “destructive” he includes fist-sized meteorites that hit cars and houses, so >99% is certainly right. If he is referring to ones we need to – or CAN – do anything about Chelyabinsk is a good place to start.”

    This is just Bos opining one thing and me disagreeing with what he argued that we SHOULD DO in the future. His opinion, my opinion. Me asking what level of destruction he is talking about is a valid point. There should be a comma after the word “about.”

    I have no idea why you are going to the word destructive. I DO think that above Chelyabinsk we have to be concerned. We need to find those and track those. Chelyabinsk came out of nowhere, in terms of our sensors. If a Tunguska comes out of nowhere, we don’t now even have a PLAN for mitigation, so mop-up is all we could do. Bos doesn’t even ADDRESS the other side of the coin – finding them and tracking them. Perhaps he assumes that as a done deal, a fait accompli.

    * * *
    Point 2: I said ““And we know that the Bos just wrote that last May simply to piggy-back on the attention that Chelyabinsk brought to the issue of mitigation. And he just HAD to be a nay-sayer to what everyone ELSE was saying at the time: MITIGATION PLANS. So he could look cleverer than everyone else, he put a twist on it and argued for, “Let’s just get ready to deal with all the dead bodies.” He didn’t want to be drowned in the cacaphony of “HEY! Let’s try to save lives!”

    I will give you that point about THAT kind of ad hominem – the ad hominem circumstantial. Not one I’d heard about before, and a rather obscure sub-category.

    The definition about it (see above) certainly fits – but this being one of those does not make his position correct, either. “This is fallacious because a disposition to make a certain argument does not make the argument false.” It does not make the argument false, but I then went on to point out what the effects of his argument are – people dying who mitigation might have saved. Had I stopped at only his (possible) bias, it would have been this sort of ad hominem. It was also mind-reading, so in that way I was being unfair. But he IS such a “Look at me!!” kind of scientist that the can – and I submit IS – affected by his public persona. That is my honest opinion, and I am entitled to it. If I was going toe to toe with him on this, that is a point I would make to his face: “Dr. Boslough, is it possible that you pulled this up just to put distance between you and others/to get yourself noticed?” In formal debate competition, you know, one is often asked to argue a side of an issue which one dies not agree with, so just because he writes a paper taking another POV does not necessarily mean the he is actually in favor of it. So it is valid to ask his reasons for coming up with it – especially in light of his method’s acceptance of people dying who would certainly be saved by a mitigation plan that works. His seeming love of being in front of the camera makes this a valid point of inquiry. Some people like being in front of the camera. Is he one of them? Is this a case where that is a motive? THE motive?

    Questioning motives IS a valid point of inquiry, and it cannot be DONE without addressing possible bias. So, though technically this is a form of ad hominem, I argue that I added enough other immediate points to make the point clear that I was questioning his bias. If bias exists it IS valid to inquire about it. If ALL it does is point at the bias, then THAT would be an ad hominem circumstantial logical fallacy.

    Dennis: “Point of fact: There is nothing in this abstract or paper that states, or implies that the next large impact WILL be a local event.

    I beg to differ. His abstract opening line is this:

    It is virtually certain(probability >99%) that the next destructive NEO event will be an
    airburst.

    His opening Introduction line begins:

    Airbursts arelocalevents

    That is pretty clear that in this paper everywhere he talks about “events” he is arguing about local events. Discussing civil defense just accentuates the local nature of what he is talking about – even when he says such things as

    More massive fireballs generated by larger NEOs can descend all the way to the surface and expand radially, leading to incineration of organic material and melting of alluvium and surface rocks.

    But after discussing “INCINERATION OF ORGANIC MATERIALS” – AS IN HUMANS, does he then go to how to deal with the incinerated humans? NO.

    Where does he go? The very next sentence is to draw attention to his LDG work.

    This is consistent with observations of Libyan Desert Glass from an event in the western
    desert of Egypt 29 million years ago.

    My first reaction with this is WTF kind of a human IS this guy? To blithely jump from incinerated humans – with no attention given to dealing with them – and directly to one of his pet projects. WOW!

    You don’t see some attention-grabbing there? Directing people away from incinerated humans (organic materials) and TOWARD his LDG papers?

    I think AT THE LEAST this is callousness in the extreme – the kind that Robert Oppenheimer and others on the Manhattan Project had a great deal of soul searching about.

    I didn’t say this. HE DID.

    * * *
    Point #3: I said, “On another front, his Figure 2 shows exactly what I was criticizing – his magical airburst just a few meters off the ground. THAT scenario is ridiculous, that THAT close of an airburst can happen. He claims >99% airbursts over impacts. I claim his low LDG airburst (his label, not mine) is absurdly improbable.”

    Your response went in this direction:

    “Dr. Boslough went to the places…”

    What does THAT have to do with him looking at several model run outputs and selecting the ONE and ONLY the one that has the airburst just above the ground and THEN arguing everything as if that Goldilocks height was THE airburst height for the LDG? HE is required to give the odds on that special case – NOT ME. It is HIS extraordinary claim, NOT MINE.

    Him being at the site does give him the opportunity to look for evidence as in glass samples, other possible impact materials or airburst materials, and to look for one or more craters. Him having BEEN THERE does not make his math any better or worse. The two things stand apart. His taking samples does not make his math any better OR WORSE, either – unless within his equations the inclusions and material composition is a factor – and it WELL might be. (Though I doubt the material characteristics would change his airburt one iota. At least IMHO. I welcome being shown the error of my ways.

    * * *
    Point #4: “I wonder, how much honest to somebody-check-me-on-this science can a man get done do from the comfort of his own living room?”

    I DO believe that when things don’t make sense to me, logically or in contradiction to other things I know, I am entitled to ask questions – supportive OR skeptical. I may not ask them well, or point out things well, but I DO try to. (That is why some of my comments are so annoyingly long – which I sometimes apologize out loud for but always I do wish it wasn’t necessary.)

    For example, if I MYSELF went there, does it mean that MY math would be good. NOT A CHANCE!

    * * *
    Point #5: Dennis: “I’m afraid real science done by someone who’s actually gone out into the field turned over some rocks, collected some real data, and ran the numbers, trumps the unsupported proclamations, assumptions, personal objections, and cognitive bias of an armchair theorist every time.”

    Dennis, you know that I APPLAUD your going out in the field and seeing so many sites yourself.

    At the same time, I have NO idea whether you yourself “ran the numbers” on the artifacts you acquired. Or had anyone else run numbers on them.

    I DO know that OTHERS besides Bos have gone out to collect LDG samples and come up with completely different conclusions about their genesis.

    I DO argue that his flight paths and Goldilocks airburst heights have NOTHING TO DO with any material characteristics of the LDG glass or any of their inclusions (which are kind of all over the map).

    Being on site on the LDGs, before forensics, I cannot see how that goes one whit toward quantifying a flight path or airburst height. And in that sentence the operative word is “quantify.” Qualitatively, by being on site, one or more conjectures can be ruled out. And one or more conjectures can be added or included. But qualitative isn’t science. Especially not without quantitative to suggest the qualitative insight is correct. YES! The qualitative insight IS necessary – but it can’t show by itself that it is correct. Numbers numbers numbers. Measurements. Empirical measurements – whether via sensors in the field or lab equipment – THAT is the science of it all. Models? Thinking tools – not empirical and therefore not real.

    IOW being on site – without measurements – can’t tell anything for sure, though it may point in valuable directions – and away from dead ends.

    Point #6: I said “Well, if he NEEDS that close of an airburst, then where are the fragments? To get that low the object needs to be larger than Tunguska, yet a larger object airbursting is going to have at LEAST ONE fragment (and certainly bigger ones) as big as Chelyabinsk’s 300 kg main body. If so, where is the LDG main body? Even one as big as Chelyabinsk is going to have fragments that can be found. But those don’t exist in the LDG area”.

    Dennis: “You’re assuming a specific composition/structural integrity that hasn’t been described. But I wonder how many large fragments of icy bodies such as a typical comet fragment might disappear without leaving any trace on the ground beyond fire damage, and strange, enigmatic geomorphology.”

    It is not correct to say that “a specific composition… hasn’t been described.” Reality has described it for us. We have Tunguska and we have Chelyabinsk, the two largest airbursts in recorded history that we presently have any research on. Tunguska is extrapolated from much field work over about 80 years. Chelyabinsk has solid current study on it. The two fall somewhat in a fairly narrow range. I understand that Chelyabinsk more or less confirms many things about the composition of Tunguska. BOTH seem to fall within the norm for meteors/asteroids. Neither one seems to be a comet. Ergo, I will argue that we presently should consider Tunguska and Chelyabinsk to fairly well represent what we will probably face in the next few decades and centuries.

    WHY? Because – as Chelyabinsk came out of the family of Apollo asteroids, which are NEOS – NEOS are the likeliest impactors, as far as we know. That is my understanding of the current state of the science. If I am wrong, PLEASE point out my error.

    Chelyabinsk was a type LL chondrite. Ordinary chondrites (of which LL is a subset) are 89% of all meteorites. Type LL chondrites make up 8-9% of that 89%. Type LL chondrites are the lowest chondrites in iron and metal composition. Therefore I take it as safe to assume that the other 80-81% of meteors are more dense than Chelyabinsk.

    Thus it is ENTIRELY fair to assume that future meteors will be, if anything, as dense or more dense than Chelyabinsk.

    Comets? Comets impacting the Earth – as much as we’d like to make them the major player here at CT – are much less likely to impact Earth. Call me irresponsible, but that is what I’ve understood from my information acquisition. If you have contradictory info, plase let me know. I thought part of the difficulty of the YDB impact hypothesis is trying to even ascertain if comets have it the Earth since the K-T impact.

    So, if most impacts are meteors (they are) and most meteors are MORE dense than Chelyabinsk, then what is wrong with what I have stated, in terms of the likeliest impactors or airbursters? I don’t see a problem. Please inform me of where my mistake is, if you see one.

    If comets are more likely, let me know. If somehow the majority of future meteor impacts are carbonaceous or other non-metallic chondrites – unlike past history – let me know.

    * * *
    Point #7: Dennis: “A wide range of conditions, and combinations such as impact angle, velocity, and bolide composition, were simulated to provide some clue as to the scaling of airbursts. Now since Dr. Boslough has actually been on the ground there accompanied by numerous geologists who helped to produce an updated geological survey the LDG, and since every one of those sims can be accessed online at the Sandia website, then pointing out the one that’s the most consistent with the geomorphology they found in Libya doesn’t fit the definition of ‘Cherry Picking'”

    Again, being “on the ground” at the site doesn’t mean his assumptions are correct, nor is math – though I am not questioning his math, per se. I am sure his math reflects his assumptions admirably. I repeat, if I myself had gone there, there isn’t a chance in hell that my math would be correct – ergo the personal presence there means nothing as far as the math goes. Again, they are two separate things.

    As to Bos’ team of geologists, I’ve just posted one paper link (previous comment) that comes to a completely different conclusion about the LDG. And I’ve given you a list of other people who have come to other conclusions.

    What does that mean? That Boslough’s hypothesis is just one of several. And every one of those paper authors is reasonably sure that his/her conclusions are correct. If they agreed with Boslough, the more recent ones would certainly not have been researched and written. And they can’t ALL be correct now, can they?

    Ergo: The current state of the LDG mystery is that it is still up in the air.

    * * *
    Point #8: Dennis: “I wonder, how much honest to somebody-check-me-on-this science can a man get done do from the comfort of his own living room?”

    I have to throw this one back at you: What percentage of your OWN time has been in the field, since you’ve begun delving into any of this? 1%? 5%? And the 95% or 99% of the time that you spend at your own desk, does this position of yours about me mean that your own science done “from the comfort of your own living room” has no merit? That you also cannot have any valid things to say, no valid questions to ask, no ponderings of merit? Is 95% of what you do of no value? Or 99%?

    I don’t think so! I think you contribute a LOT here, and you did even before you went out in the field. AND SINCE.

    So can you please stop pointing out that I don’t work in a national lab?

    IF THAT IS NOT AN AD HOMINEM, I DO NOT KNOW WHAT IS.

    George doesn’t work in a national lab, and yet he contributes to papers from time to time, yes?

    Have I? Not yet. Will I? If given the opportunity, I would love to. I DO think I have something to offer. Others do appreciate my questions and occasionally my input. All I can do right now is put my best thinking forward.

    * * *
    Point #9: I said “He can’t have both a bigger body and NO fragments large enough to find in the LDG strewn field. Even a Chelyabinsk-sized object would give him SOME fragments on the ground.”

    Dennis wrote: “Yeah, that unsupported assumption might fly if someone, sometime since 1908 had ever found a fragment of the Tunguska object. This in spite of the fact that it was much bigger than Chelyabinsk, and the fact that countless people have searched for it for more than a century.”

    Dennis, I don’t really have to point out the difference of finding things in the snow near Chelyabinsk vs finding things in the forest and bogs and ponds and lakes around Tunguska, do I? Or the flat desert of the Sahara where the LDG is found? The number of Tunguska searchers for meteor remnants is not “countless,” as you say. There has been a finite number of them.

    Had an equal number gone out into the desert of the LDG would they have found meteor fragments? I mean Boslough himself says how big the body was supposed to have been, and that body was 100 meters from what I read, according to his numbers. Tunguska was about 60 meters and Chelyabinsk was about 17 meters.

    I fully acknowledge that the internal unit strength of any two objects will be different. But one would think that an object 6 times as wide would have about 200 times the mass, give or take perhaps a factor of +4/-8. Yes, a guess. Which I think is not unreasonable. 200/8 is still about 25 times as massive as Chelyabinsk – and that is assuming a Type LL chondrite, the least dense of ordinary chondrites.

    On a desert floor, fragments from an airburst should exist and be easily found. ALL of the object did not disappear. If ALL of the object had ablated away, there would have been no airburst possible. For an airburst at the level Boslough suggests, a LOT of material had to still be intact at the point of the airburst.

    An airburst is not an event that makes physical material go POOF!

    * * *
    Point #10: I said: “Models simply are NOT reality. Not unless ALL the parameters are well known and tested.

    Using models to simulate hypothetical conditions can help the thinking process, but to present model outputs in such a hypothetical as real, that really is not science.”

    Dennis: “This is a straw man argument because it never really happened.

    Point of fact: There has never been a time, in any of Boslough’s work, or talks, on the subject when any those sims have been presented as anything more than a model, and compelling simulation of what he believes probably happens during an airburst event.”

    We both know that he allows others to treat his stuff as real. Same thing, IMHO. And I AM entitled to my opinion. TV documentaries don’t come out and say, “But this is all just hypothetical and the images you are seeing may be magnitudes off the mark. And what the images show may not be correct at all, either.” They make a big deal that he is from national lab, and they present his work as “the best science.” And they do not bring in the alternative hypotheses in any fair (i.e, equal) light. And don’t put that on THEM. HE sure doesn’t point out its “iffiness,” neither to the producers nor the audience. Nor does he point to the alternative hypotheses.

    So, by his one-sided presentation, his ideas are put forth as THE answer. It isn’t necessary for him to say, “Look, folks, this is all based on a lot of guesswork.”

    I don’t mind guesswork – as long as it is made clear about the iffiness and that the case is NOT closed.

  • Why wouldn’t an ablative airburst event produce shocked grains? Remember, there also is no crater geomorphology at the LDG site.

    We should hope they do though. Because otherwise, an event that’s identical to the LDG in every way could’ve hit North America anywhere from the Mexican volcanic ark, to the volcanic fields of New Mexico, West Texas, or Colorado, and the resulting melt would be virtually indistinguishable from plain ole lava.

    For example, andesite lava is the product of melted sandstone. And the andesite cores that were pulled up from Chicxulub were first held up as conclusive evidence of volcanic origin for the structure. It wasn’t untill shocked grains were detected that the truth was realized.

    The 10 cm thickness of the impact layer the YD team turned up down in Mexico would tend to imply that Mexico took the brunt of some major ET violence. But that place is also one of the most active volcanic fields on earth. If there are no shocked grains to be found, there will probably be no easy way down there to differentiate between impact melts, and normal volcanogenic rocks.

  • An ad hominem argument does not have to be negative to be erelevent. Bottom line: None of our personal opinions of any given scientist, researcher, or organization, and no matter if that opinion is negative, or positive, are even remotely relevant in this discussion. Keep it objective, about the data, and about the science, and not about the man, or the organization standing behind him, and we’ll all get along just fine.

    P.S. I note that the paper you cited does not disagree that LDG is an impact cite. But in fact they didn’t find any crater geomorpholgy either. And you can’t say it was not an airburst without one.

  • You’re pretty good at piling on the word salad when sharing, or expressing your subjective opinions Steve. But your weak point is that, while you pile on the word salad with your personal disagreements, and objections to something, you almost never give us an objective comparison of the actual data being discussed with any real data that might conflict with it, and actually support your subjective opinions, and objections.

    So that a debate which should be centered on the physics, and merits of a new, and theoretical impact mechanism has somehow become about you, and your many subjective reasons for having a low opinion of it’s source, and the supposed academic, and political biases of that source, instead of the actual impact theory itself, and the data being presented.

    Unfortunately, since you keep going on, and on about exactly which position, or altitude something explodes at it seems you don’t even have a clear understanding of what the Boslough sims are actually showing; much less the actual impact model described, or how it differs from the old way of thinking about what happens during an air burst, or the atmospheric entry phase of an impact event.

    Simply put: At it’s core, the fundamental difference between the Boslough model and the old way of looking at an impact goes to the retention of momentum.  Before the advent of super computers, all of the old impact models had the object exploding at a specific altitude in a point detonation similar to a nuclear explosion. But the use of supercomputers allows them to retain the downwards momentum of the impactor in their calculations, and to run iterations at millisecond intervals. When you do that the speed of the expanding explosion is seen as roughly equal to the downwards velocity of the exploding meteor. So you get a kind of moving explosion that gets stretched out along the entire entry path of the object instead of point detonation at a specific altitude like a nuclear explosion.

    We saw this recently at Chelyabinsk. The explosion there was obviously not a point detonation.

    So it’s that simple component, the retention of downwards momentum during an airburst, that’s at the heart of Boslough’s model, and what sets it apart.

    Now you can go on and on all you want with endless piles of word salad about your low personal opinion of Boslough, and any supposed bias you claim he might have towards a given viewpoint. You can also keep on going at it saying that his model is no good because you don’t trust the political/funding motivations of a national lab. But it’s not about you, or your subjective opinions. So it’ll all be nothing but so much word salad, because not one word of your personal opinions of Boslough, or Sandia, or any bias you’re convinced they are leaning towards, will be even remotely relevant to this one simple question:  Is the retention of momentum valid in an impact model?

    There is no grey there. Either it is, or it isn’t. If not, then the old way of looking at things stands, and we assume as we always did before that air bursting objects all reach some magical attitude, and detonate in a point explosion like a falling nuclear bomb, and the Boslough air burst model is wrong, and doomed to obscurity.

  • But if the retention of momentum is valid, then Boslough’s models are at least on the right track, and all of the old impact models belong on the same shelf as flat Earth theory, and need to be reworked.

    If you can show real data that shows the retention of momentum in an impact model is a mistake, I’d like to see it. But  your personal opinions of Boslough, or Sandia, and any biases on their part that you might perceive, have just about equal value, and relevance, to impact science and the question of retention of momentum, with Ed’s often expressed low opinions of David Morrison, and NASA. 

  • Steve Garcia

    “Why wouldn’t an ablative airburst event produce shocked grains?”

    Look up how ablation works. YES, it is rapid expansion, so the acceleration can do some things. As far as I know, no explosive process on Earth can equal the shock effects of a hyper-velocity impact. Dennis, if you can find where the forces are the same, let me know. I will be educated. But from what I know, the rapid acceleration from ablation and vaporization is insufficient.

    “Remember, there also is no crater geomorphology at the LDG site.”

    I am fully aware of that, and I agree with you. But this argument is not MY argument. As such it should be addressed specifically against those authors of those papers.*** And in doing so, you will be challenging academic papers just as I am doing. AND I SUPPORT YOU CHALLENGING THEM. YOU don’t require a doctorate in physics in my book – I respect your judgment (even if I don’t always agree with it). But I am just pointing out that those other hypotheses DO EXIST, making Bos’ hypothesis not the only one out there.

    *** And yet, the evidence they bring up is REAL. How to rectify that with other facts? At this time I DO NO KNOW. But the evidence from those other papers is not to be sloughed off with a wave of the hand.

  • Steve Garcia

    Dennis: “We should hope they do though. Because otherwise, an event that’s identical to the LDG in every way could’ve hit North America anywhere from the Mexican volcanic ark, to the volcanic fields of New Mexico, West Texas, or Colorado, and the resulting melt would be virtually indistinguishable from plain ole lava.”

    OOOOOh, no, I would not say that at all. First of all, there are several TYPES of lava, depending on the magma coming up from deep below. Even for ones that come from similar volcanos, some are created while under pressure, and some come out differently because they form at atmospheric pressure. From geology.com/rocks/igneous-rocks.shtml:

    Igneous rocks are formed from the solidification of molten rock material. There are two basic types: 1) intrusive igneous rocks such as diorite, gabbro, granite and pegmatite that solidify below Earth’s surface; and 2) extrusive igneous rocks such as andesite, basalt, obsidian, pumice, rhyolite and scoria that solidify on or above Earth’s surface.

    Trust me, those are very different rocks.

    And then there is Welded Tuff, too (same source):

    Welded Tuff is a rock that is composed of materials that were ejected from a volcano, fell to Earth, and then lithified into a rock. It is usually composed mainly of volcanic ash and sometimes contains larger size particles such as cinders.

    That is just a start. There are quite a few igneous rocks, and I am pretty darned sure (off the top of my head) that melted surface rocks will not be the same as any of them. The pressures at solidification, plus the actually minerals present determine the end result, not just heat.

  • Steve Garcia

    Dennis: “For example, andesite lava is the product of melted sandstone.”

    Not correct. Andesite is NOT the result of sandstone melting. One is igneous (extruded under pressure from deep below) and the other is sedimentary (laid down in layers on the surface).

    Geology.com says:

    Sandstone is a sedimentary rock composed of sand-sized grains of mineral, rock or organic material. It also contains a cementing material that binds the sand grains together and may contain a matrix of silt- or clay-size particles that occupy the spaces between the sand grains.

    Sandstone is one of the most common types of sedimentary rock and is found in sedimentary basins throughout the world. It is often mined for use as a construction material or as a raw material used in manufacturing. In the subsurface, sandstone often serves as an aquifer for ground water or as a reservoir for oil and natural gas.

    Andesite is a fine-grained, extrusive igneous rock composed mainly of plagioclase with other minerals such as hornblende, pyroxene and biotite.

    Sedimentary and igneous rocks are two completely different animals.

  • STEVE; I’ve been gone from the site for a little bit and have been reading like crazy to catch up. My last bit of reading was about the string of pearls effect and what is causing it. My take is that as the comet breaks up the lighter peices “slow down” and fall further back in line and the larger ones tend to stay closer to the main body. I’m not sure if the larger pieces are staying closer to the main body because of the their larger size being a larger target for gravitational pull of is it just that their inertia is proportinately larger causing them “slowdown” slower. Another idea is that they may appear to be following each other in a line but as the line stretches out the furtherest back ones may be falling in somewhat quicker but still retaining the appearance of being in a line. I’m not sure if this makes any sense but there it is.

  • Steve Garcia

    agimarc –

    Much food for thought in the discussion. A possible explanation for a distribution of comet fragments in a line (from our perspective) or more likely in a plane would be tied to the rotation rate of the comet itself.

    “In a plane” I very much agree with. The Taurids have two main population streams – north and south. These two bands (as I have seen them depicted) are much wider than they are tall. I envision the entire populations with each fragment doing sine curve paths more or less, internal to the stream, up and down from the ecliptic, due to their encounters with planets and their mutual gravitational forces and their initial movement awaay from the main body. Those vertical forces I perceive as having less amplitude than the left-right forces (parallel to the ecliptic) of their planetary encounters. It seems reasonable that the default position for each fragment is ON the ecliptic, but subject to vagaries of planetary encounters and the solar wind and whatever other small forces occur in their lifetimes, all of which give them all a bit of meander out of the plane of the planets. Planetary gravity along their paths stretches them out sideways in both directions (in addition to forces and movement somewhat equal to the vertical ones), and these combined sideways forces would be larger in magnitude than the vertical components. That all seems plausible and even perhaps likely. (I doubt I explained that very well.)

    Once it comes apart, my guess would be due to the action of differential heating of ices inside it, which also provide a propulsive impulse, the rotational energy of the body will be carried away by the chunks as they depart. For a simplified version, think of a flywheel coming apart at speed or a turbine section breaking apart during flight. An irregular body should be a lot more complex as it should be rotating (or tumbling) far slower and as pieces start breaking off, it redistributes the mass and changes the rotational axes.

    Based on the dirty iceball concept, that is all reasonable. But just a reminder that idea of the ice – as in dirty snowballs – has been discarded by many as to what comets are about. And besides that, many comets have characteristics of asteroids and vice versa. A NASA paper from the 1960s that I can no longer find concluded that 47% of the Apollo asteroids had at least one cometary characteristic. In addition there are Main Belt Comets, which are comets that don’t approach Earth but stay in the Asteroid Belt and act like asteroids except for their make-up. So the whole thing is much more complicated than the black-and-white comet OR asteroid simplistic picture we learned in grade school.

    There is an effect called the YORP Effect by which sunlight shining on asteroids will change their rotation rates and occasionally even their orbits. It is thought to be significant enough to spin smaller objects to the point that they disrupt.

    Adding to this discussion… In the second link you gave above (about SW-3), the author says this about rotation and thermal heating/outgassing:

    In addition to citing possible “thermal stresses”, the Hubble Space Telescope website offers other possibilities as to why comets might disintegrate so explosively — “They can also fly apart from rapid rotation of the nucleus, or explosively pop apart like corks from champagne bottles due to the outburst of trapped volatile gases”. But the centrifugal forces acting on comet nuclei are close to zero. And to posit heating in the middle [center] of a mile-wide dirty ice cube is, again, scientifically indefensible.

    It must be noted that that site is an electrical universe site, so it’s assertions should not be taken without some critical faculties at work. At the same time, that passage I see as being sensible and reasonable.

    As to his counter arguments, I’d say he is wrong about centrifugal rotational forces. I think the amount of centrifugal force can be all over the map. Sometimes minuscule and other cases quite high. At the same time, comets that remain intact more or less when they get to the neighborhood of Earth probably have a higher level of cohesion, since they have been battling the sloar wind without disintegrating.

    On the explosive gases, my two cents would be that I DO doubt that much trapped gases exist in comets. There is little reason for them to be there trapped. Trapped LIQUIDS that are frozen? Perhaps. (But then why would they vaporize into gases?) It goes to the hypotheses of how they are formed. We must also include the lack of atmosphere on smaller planets and moons – the idea that they long ago had their atmospheres waft away out into space. If planets and moons, with their much greater gravity, have lost their gases/atmospheres, why should we assume that such gases can exist within ultra-low-gravity bodies a few tens of meters across? Just because they tell us it is so? Where did the gases come from? How did they get trapped inside? Chemical reactions? Simple gravity? How did the body wrap itself around the gas molecules, trapping them? How did the gas molecules accumulate? Wouldn’t their gases be lost to space like small planets’ atmospheres? This whole thinking has big holes in it.

  • I never said dirty snowball, as that model has been replaced by something a lot more complex. John Lewis has been estimating for decades that half of earth crossing asteroids are comets.

    OTOH, if you have a body with a measurable percentage of ices mixed in with rocks, dirt, dust, etc, those ices when exposed to solar heating will either sublimate or boil off. If they are buried under the crust of the body, that crust will heat and retain the heat while the body is in the inner solar system, boiling the subsurface ices into gas, which is where you get the jets off cometary nucleus from. Its only trapped gasses while the ices boil. Take a look at the jets off Hartley II (19P/Borrelly also has great photos of jets):

    http://www.astronomynow.com/mag/1102/EPOXI.html

    Tempel I was hit by Deep Impact in 2005. It is thought to be at least 50% ice. Impact spectra was fascinating with more dust than expected. Note that they also saw spectra of polycyclic aromatic hydrocarbons (PAHs) – benzene is an example. Link follows.

    http://www.bibliotecapleyades.net/ciencia/ciencia_asteroids_comets_deepimpact14.htm

    What happens when you heat and cool bodies time after time is they build a crust of ice-deficient rock, dust and PAHs. The only way we can tell what an inactive body is composed of is to either hit them with something or visit them. Otherwise you are limited to observations from a distance.

    Most of us in colder parts of the world see what happens to a mixture of ice, rock, salts and dust when it is exposed to heat over a period of time. There are things called snow dumps. They are where you put snowfall from the roads so it is no longer on the roads. Over the course of the spring and summer, the pile of snow grows a dark crust and melting slows down as the crust insulates the snow under it from the action of sun. Eventually the pile melts completely leaving a pile of dust, crushed rock, gravel and trash to clean up. We see the same sort of thing when a pristine comet enters the solar system. Remember that most of them already have a crust if for no other reason than the ices sublimate in the cold outside the confines of the outer solar system. Once the comet fragments, the ices are exposed to the heating action.

    Generally, the farther you get from the sun, the percentage of ices making up the smaller bodies increase. There are a few bodies that fall outside this observation – Io which has been tidally worked for billions of years and no longer has water ice, and Vesta which appears to have been bombarded. Interestingly though, Ceres is thought to have significant amount of ice. We will find out about that next year when Dawn enters orbit around it.

    As to where the ices come from and end up as part of a small body, that is the part we are still arguing about. We have telescopically observed water molecules and PAHs in nebulae so we know they exist elsewhere. How they go from gas to ice to part of a larger body is another thing entirely. Cheers –

  • Agimarc;There is a theory out there that there was a planet between earth and mars that was impacted of exploded causing the asteroid belt to exist. If this is the case then asteroids and or comets could be the remnants of destroyed planets from our galaxy or from others. The odds that we are the only water baring planet are against us. And the odds that no other body out there could have ices of any kind is naive. I can see the ices going to vapor as a comet or asteriod comes closer to our sun in their travels due to the different vapor densities of the chemicals in the ices, and once enough ice has offgassed any solids left would be free to come apart either explosively or just drift back as gravity or solar wind dictates.

  • Howdy Jim –

    Don’t ascribe to the notion of exploding planets on a couple of levels. First there’s not enough stuff out there and second it can be better (and easier) described by migration of the outer planets outwards triggering the Late Heavy Bombardment (LHB). And an exploding planet in the position of the asteroid belt would be high in rock content vs ices. Even with that, we have a pair of dwarf planets in the main belt – Ceres (with ice) and Vesta (mostly rock). The Jupiter trojans are thought to be Kuiper Belt objects.

    http://sservi.nasa.gov/articles/nlsis-swri-team-investigates-wandering-gas-giants-and-late-heavy-bombardment-moon/

    As you move out from earth’s orbit, you encounter bodies with increasingly large percentage of ices all the way to the Kuiper Belt where they are mostly ice. The closer we look at Mars, the more ice we see. Go the other way toward the sun and there is evidence that water mostly delivered during the LHB boiled off during time or was not retained. Sometimes it helps being the right distance.

    Planetary oceans are suspected on the moons Europa, Ganymede, Titan and Enceladus. Io is also thought to have an ocean but it is not water. Rather it is thought to be molten sulphur.

    Don’t discount the impact of boiling ice in a differentially heated body like a rotating comet. Better yet, there is a thing called amorphous ice that catastrophically rearranges its crystalline structure upon heating. Don’t know that I understand it all that well but it is supposed to form in very cold conditions (deep space). Cheers –

    http://www1.lsbu.ac.uk/water/amorph.html

  • Agimarc; Thanks for the reply.So much info out there to punch a hole in a perfectly good idea. Oh, well. I’ll just keep plugging away and maybe get it right.

  • Steve Garcia

    Agimarc –
    “…exploding planets . . . First there’s not enough stuff out there”

    Mostly just tweaking you here, but let’s start with:

    Neither the Sun nor Jupiter could have possibly any gathered “stuff” in. As long as there are impacts on all the planets, and as long as we know zip about the history of the Sun, “there’s not enough stuff out there” has no basis. And just how big is this “stuff” progenitor supposed to be, that there isn’t possibly enough of its “Stuff out there”?

    I won’t even point at the Great Red Spot and wonder why it is there.

    “The Jupiter trojans are thought to be Kuiper Belt objects.”

    “Are thought to be” isn’t an evidence-based argument. It is an opinion. At least you didn’t say, “…are thought to be Oort cloud objects.” Do you have any evidence for why (for example) the Jupiter trojans cannot have been fragments from an exploding planet? Because we believe in the Kuiper belt or Oort cloud but don’t believe in exploding planets – that is not exactly convincing.

    “And an exploding planet in the position of the asteroid belt would be high in rock content vs ices. Even with that, we have a pair of dwarf planets in the main belt – Ceres (with ice) and Vesta (mostly rock).”

    This is confused and self-confuting. And exploded planet would mean MORE rock content, but then you point at two ROCK objects as argument for why there would BE high rock content.

    At the same time, I agree that there would be more rock than ices.

    At the same time, we don’t know what the gas giants’ bodies are made of, and we know darned LITTLE about the body of our own, except by inference. All of this may be argued against, but all gas giants’ bodies can also only be inferred, not known.
    From Universe Today:

    The answer to ”does Jupiter have a solid core” is that the planet has a core that contains some rock and hydrogen metals. Scientists are not sure if deep within the planet there is a solid core or not. All that they can do is gather gravitational measurements, compare them with Earth’s, and make the best educated guesses possible based on those measurements. Those measurements make them think that the core is a thick, super hot soup.

    Jupiter’s composition is by-and-large a mystery. Generally accepted theory holds that it consists of a dense core made of a mixture of elements, the core is thought to be surrounded by a layer of liquid metallic hydrogen and helium, then the outer layer is proposed to be dominated by molecular hydrogen. The core is often speculated to be rocky. It wasn’t until 1997 that the existence of the core was even theorized. Gravitational measurements were taken, which indicated a mass of from 12 to 45 times the Earth’s mass. That would mean that the Jovian core accounts for about 3–15% of the total mass of the planet. The presence of a planetary core follows accepted knowledge of planetary formation.

    Source: http://www.universetoday.com/14470/does-jupiter-have-a-solid-core/#ixzz37bl0l7dz

    We do know that Jupiter has been around for X billion years, probably about the same as Earth’s 4.5 billion years or so. Astronomers sign onto the accretion hypothesis, which argues that the planets agglomerated material by gravitational forces. But planets LOSE gaseous materials. So, there is Jupiter, in the middle of it all doing pretty much exactly the opposite – accruing so much gas and so little solids. With so many comets over time impacting on Jupiter (is it THREE in the last 20 years?), over billions of years why wouldn’t Jupiter have accrued many thousands of cubic miles of solid mass? (Yes, based on its low density, we can’t exceed a certain total.)

    Wow. That link goes to a summary of what is presently thought to be, which is fine – as long as it is only presented as what we currently think. It has a LOT of caveats:

    “may have caused”
    “may have been”

    “simulated” (computer models are not reality)
    “could have happened”
    “would have affected”

    “have concluded”
    “the apparent clustering of ages”
    “proposed that it represented”
    “the planets may have roamed”
    “Jupiter seems to have migrated”

    “Current theory says”

    “might have become highly elliptical”

    “dynamical simulation of the late heavy bombardment” (computer models are not reality)

    Removing the “if statements,” the article has little to no solid empirical evidence. We can’t just go around telling each other that so-and-so says or thins something. As long as what they have said or think cannot be tested, it has to remain a hypothesis, if that.

    The Late Heavy Bombardment: Wiki starts out this way:

    The Late Heavy Bombardment (commonly referred to as the lunar cataclysm, or the LHB) is a hypothetical event thought to have occurred approximately 4.1 to 3.8 billion years ago…
    …the cataclysm hypothesis has recently gained in popularity, particularly among dynamicists

    Hypothetical, as in hypothetical… As in “thought to have occurred”. So it is not anything solid. I think even in the section on Wiki about Criticisms of the LHB, the criticisms are weak and certainly cannot be the entire argument against it or its details.

    Dynamicists’ opinions are not the only opinions. So this hypothesis has a long way to go to being settled science.

    So, Jim, don’t give up on it so easily. The GREAT majority of the history of the Solar System is hypothetical. The empirical evidence is VERY piecemeal, and different minds put those few puzzle pieces together differently. Challenge the opinions as given, with your own intellect and dig deep. The great majority of what was in that article about the LHB I take with a grain of salt – because it is all speculative. Good minds? Certainly. But all good minds have thought things that turned out to not be true later on.

  • Steve Garcia

    “The default position of science is skepticism.”

  • Steve; Moocho Grassy ass for the chin up and carry on. There is so much info out there that is or is not correct at this moment,it’s hard to keep up with and make hay. I’m relying mostly on my gut feelings on things, but others have their instincts and knowledge and put out some very logical sounding arguments then I have to wonder if they are correct or not. It does keep ones mind extremely active does it not? I’m keepin on keepin on and sooner or later I’ll get it all together, Maybe!

  • Agimarc; I went to the Nasa site from your link about the LHB and it was talking about how Jupiter Saturn Neptune and Uranus orbits were quite erractic from planetismal collisions and gravitational disruptions and that the gravities of Neptune and Uranus caused each other to be repelled. Also they talked about the debris from all these collisions being repelled out into space away from the planets. My question, if I read this correctly, is that I thought gravity was an attractive not repulsive force. How can it repel objects away? That sounds more like magnatism than gravity.

  • Steve – I treat the existing LHB description as a place holder until something better comes up. Good enough for today? Perhaps. Rock solid explanation of what happened? The jury is still out as it is still pretty new (not unlike the YD which we are all wrestling with). But to me, it does answer a lot of questions while raising a lot more.

    We’ve gone round and round on exploding planets before and will continue to disagree.

    By not enough stuff, I mean that if you destroy something large – say between the diameter of Ceres and Mars – in the vicinity of the belt, where does that mass all go? Inner system? Outer system? Ejected by Jupiter? Into the sun? At the very least you will get a version of the LHB – perhaps even the LHB itself, though something needs to move the outer planets outwards as they appear to have formed closer to the sun than where they currently reside. And when they move outward, they will gravitationally disrupt the Kuiper Belt objects that formed beyond their orignial orbits. It is those object that create the LHB, oceans on the earth, lunar maria, etc.

    We are also left with the small problem of what causes a planet to explode? We know that impact can do the trick, but timing is everything. If this planet(-oid / -esimal) was destroyed in the early stages of planetary formation when there were hundreds to thousands of largish bodies careening around the disk, how can you tell the difference before and after? If it took place after everything settled down before or during the LHB, once again, how can you tell the difference? If it took place after the LHB, we don’t see either the newer large impact craters or the out of plane of ecliptic mass.

    And yes, we have also gone round about planetary formation and will continue to disagree. Like the LHB, to me it is a place holder until something better comes around. Cheers –

  • Jim –

    As I (poorly) understand it, the gravitational interaction between Jupiter and Saturn was enough to move the orbits. And when the big boys move, they herd the little guys (Uranus and Neptune) ahead of them. Some of the simulations propose a similarly sized planet that was ejected and have Uranus and Neptune swapping places during the festivities. The thing I pick up on are the orbital resonances – which is around 2:1 between Jupiter and Saturn – which tends to keep them in somewhat of a sweet spot (think minimum energy) gravitationally. We see a resonance between Neptune and Pluto of around 3:2.

    http://www.nasa.gov/topics/solarsystem/features/young-jupiter.html

    Gravitational / tidal interactions between the earth and moon have been slowly moving its orbit outward since its formation. Currently the moon is drifting about an inch and a half a year outwards and will end up with both bodies tidally locked about four times the current distance in some 16 – 18 BY, far after the sun goes red giant and forms a planetary nebula.

    http://www.bbc.com/news/science-environment-12311119

    Cheers –

  • Steve Garcia

    Agimarc – “I treat the existing LHB description as a place holder until something better comes up. Good enough for today?”

    Oh, absolutely.

    That IS one of my points, and I am glad you see it, too: WE ARE AT SOME POINT ON THE CONTINUUM, no more and no less. The continuum? From the Dark Ages of thought to 100% certain empirical knowledge about everything. And how far along are we? About 350 years, since the time we began systematically inquire and catalog. Prior to that humans jumped the gun and started to try to connect, but with insufficient evidence and measurements.

    I think we today are still in what should be the cataloging stage, because we have so little to go on. But the ones who jump to conclusions are the ones who get the headlines. It’s kind of sad, IMHO. It’s kind of natural with a lot of us (males in particular) to try to solve puzzles and mysteries, so we DO jump the gun. But the rest of us should be putting the brakes on those who do. At least a little bit. Especially when the “those who do” is us. But we can still have fun throwing it back and forth. Le’ts make sure we keep the fun in it.

    As to your paragraph about the LHB, yes, all or most of that is reasonable. Reasonable itself doesn’t make it correct, but reasonable is cool. But all of that can also be explained via the exploding planet, too. In THAT reasonable way. The least unreasonable thing about the exploding planet is that it is a catastrophic event, so the non-catastrophists avoid including it. I get that. But so much of their basic stuff is also in its way unreasonable. Such as planets and asteroids accreting with such little gravity. EVEN the Earth, things that fall on it now are not creating but destroying. The central figures in impacts are the size of nanodiamonds and carbon or metallic spherules, as opposed to agglomerating. When the products of impacts are so very small, it seems to argue against the creation of solid objects the size of asteroids. If impacts caused big solid objects, I’d see some consistency. But They don’t, so I don’t. From all I see, collisions break objects up, not create fused new objects. Not bigger than a hair’s width, anyway – and in even THAT process, so much MORE material is driven away that the net is destructive, not creative.

    …I find it odd with Kepler’s orbital ratios out there that someone can say that the outer gas giants formed farther in. Like Kepler himself speculated, those ratios seem to imply a harmonic process going on that attracts materials to certain orbits. And I would suggest that even the Trojans and Main Belt asteroids continue to display this affinity for those harmonic orbits – they certainly float themselves into those and to a much less degree any other orbits. And the objects that wander outside those orbits do not find other, in-between, harmonics, but they are either have chaotic orbits or dive into planets eventually without ever having found their home orbits somewhere.

    …The 1:2 ratio thing mentioned about Jupiter and Saturn is all well and good. IMHO, there SHOULD be some such harmonies that resonate in such a way. I DO agree that such ratios (whether that or another) will affect objects wandering out there. I think it is reasonable to ASK if that had something to do with why asteroids and comets exist. But is it actually so? Is THAT particular ratio the one? For THOSE particular planets? It really IS hard to say, because the people doing the theorizing are the same ones writing or controlling the computer code, so we must always ask if the assumptions underlying the code are true IN THE REAL WORLD. I think the code does faithfully represent the thinking underlying it. But the assumptions are the crux of it. The models are just illustrations of the assumptions, not necessarily the real world that is (hopefully) being illustrated.

    I don’t want us to go off on global warming, but in that field there are something like 95 DIFFERENT models. Though they all TEND in the same direction, there are differences between them. A basic question has to be: WHY are they different in their outputs? The obvious first suspect is the assumptions underlying the code.

    But the really NASTY thing about the climate models is this: All but ONE are projecting global temperatures to rise at a much faster rate than has been seen in real world ground, balloon, and satellite data (even after adjustments have been made). At this point it is becoming increasingly clear that nearly 100% of the models have wrong assumptions behind the code. The global numbers have shown a static rise for the last 17 years and 10 moths – and counting. Only one model reflects this. But ALL of them are still being used, to find a collective projection. And the collective projections – that includes ALL of the assumptions of ALL of the scientists – is WAAAAY higher than the reality. For some reason they are stubbornly refusing to change the models or create new ones. In fact, there are suggestions being made to begin ignoring the real-world data from balloons, thermometers and satellites, because they are not cooperating. THIS is turning science on its head, if they do this.

    So, you see, it is quite important to question assumptions in any models, because if we don’t (or can’t) compare the models to reality, we can go off in wrong directions. Especially if we begin to believe that the ILLUSTRATED models themselves ARE the reality.

    Once again, I DO have to point out that models such as used in designing buildings are far different. In those, all (100%) of the INDIVIDUAL formulas being included have been empirically tested. At NO point in the code is it allowed to put something in that is not 100% tested experimentally or empirically. So THOSE models DO have output that can be seen as reliable. They freaking better be! But when even ONE formula behind the code is IFFY, the entire output should be seen as also IFFY. And when multiple formulas are not tested in the real world, what should we think of the output? Obviously, even LESS reliable. At the LEAST that overall output should be tested against reality – but it should then be accepted only tentatively. And only after many successes (as in architecture) should it be accepted.

  • Steve Garcia

    “We are also left with the small problem of what causes a planet to explode? We know that impact can do the trick, but timing is everything. If this planet(-oid / -esimal) was destroyed in the early stages of planetary formation when there were hundreds to thousands of largish bodies careening around the disk, how can you tell the difference before and after? If it took place after everything settled down before or during the LHB, once again, how can you tell the difference? If it took place after the LHB, we don’t see either the newer large impact craters or the out of plane of ecliptic mass.”

    Yep, these are all good questions. (But I’d like the same suspicion applied to the accretion hypothesis!)

    For one thing, though, the fragments of an exploding planet would NOT all remain in and “around the “disk.” Explosions are 360° x 360° events. It easily explains why there are objects in high declination orbits. It also gives up-down motion to the asteroids in the Main Belt, as well as moons that have inclined orbits. I am not advocating it, per se, but it could also explain why plenets have tilted axes, due to off-center massive impacts.

    As to WHY a planet explodes, should I here ask that we stop using gravity because we don’t know what it is? Do we ASK HOW the Big Bang could have happened? No, of course we don’t. So, we can look at the billions of objects out there as possible remnants of an explosion without rejecting THAT because of what might have caused it to have happened. To include an impact is IMHO circular thinking – because there may not have BEEN any objects to impact it. Is there any internal forces that could do such a thing? If anything, I think THAT wold be the question. But I think the bigger question, the more correct one, would be to ask how BIG of an explosion would it have been? For example, if a planet exploded and threw fragments out, should we consider that the comets go out to the Oort cloud range or do we keep the Oort cloud? If we do, we have to conditions that might explain the same phenomena. Do we keep both? Or reject one? So far, it is the exploding planet that is being rejected. I think the Oort cloud – for which not ONE empirical piece of evidence exists – should be the rejectee.

    But maybe I am just an easy mark for alternative theories. I’d like to think that my own Occam’s Razor tells me that it is strange to reject the simpler explanations, and instead accept a patchwork overall concept that seem to always need repairing and new injections of hypothetical EXTRA events (like the LHB, separate beginnings for planets, comets, Oort cloud, etc.). But that is just me… LOL

    Again, I do not disagree with placeholders at all. As long as they are labeled as such.

  • Steve Garcia

    I might as well throw this out there – three possible mechanisms for exploding a planet, from the late astronomer Tom van Flandern’s still existing web page: http://www.metaresearch.org/solar%20system/eph/PlanetExplosions.asp

    Among other things, from the exploded planet hypothesis van Flandern predicted that asteroids and comets have satellites, for which he was long excoriated. He turned out to be right, and everyone else was wrong. As Einstein is quoted (more or less), “It only takes one real fact to prove any theory wrong.”

  • Steve –

    Well, if you’re going to be that way about it ……. (tongue firmly in cheek)

    Fun discovery by Rosetta on its way to 67P/Churyumov-Gerasimenk is that it appears to be a contact binary. Probe is going to orbit the comet for a time and put down a lander. We may find a bit out about fission, breakup, accretion, and jets starting next month. Cheers –

    http://phys.org/news/2014-07-comet-chasing-space-probe-discovery.html

  • Steve; I just read your and Agimarc’s debates and have a simplistic idea that may or maynot be valid. Orbits should be dictated by the volume of an objects mass from the smallest nano-diamond to the largest known object. Everything in the known universe is in a circular motion of some kind so the centrifugal forces would place them at various intervals within the gravitational ranges of other objects. This allows for planetary placement and the placement of moons and other cosmic bodies. I reread this a couple of times and I’m still not sure if I got it more or less the way I want it but here it goes.

  • Steve Garcia

    The contact binary status of 67P/C-G looks like an example of what I’ve been talking about.

    Would anyone here mind if I predict that when Rosetta comes within 100km and when it sends a landeer, on the surfaces of both main objects there will also be some or many smaller objects lying on the surfaces of the two bodies.

    As I see it the smaller of the two main objects is no different in kind from the small rubble lying all over the surface of asteroid Itokawa. This rubble on Itokawa was referred to as “migrating regolith” by some. The “migrating part of that is because there seem to be patterns to the rubble, suggesting that some vibrations are moving the small rocks.

    I think the focus on Itokawa being on the patterns diverts attention to the fact that the regolith is not fused to the body of the asteroid but is just lying there in contact with the surface of the main body. This should argue that such contact is the norm when two small bodies come together.

    My interpretation of this is that ALL of them – on Itokawa and on 67P/C-G – are strengthless body joinings. Meaning that the slightest touch could push them apart. A feather even could do it, because as small as the force is, it is still one of Newton’s “unbalanced forces.”

    Though the main bodies are solid – as are the regoliths – what we see on those is not the way solid bodies would be made into asteroids or comets. The making of the solid bodies is by another mechanism altogether – a process that long preceded what we see in the strengthless contact between the main bodies and the minor bodies.

    Prediction #2: When the lander jostles 67P/C-G, the regoliths will move around or away from the main body and become temporary or permanent satellites.

    Both asteroids seem to support Tom van Flandern’s prediction that comets and asteroids have satellites. To me contact binaries and smaller regoliths are satellites that have come to rest (contact) on the surface of the main body. The two are completely compatible ideas. Van Flandern bases his satellites on an exploding planet. I base my thinking solely on debris of ANY kind and from whatever beginnings.

    But I think that once in close proximity with a >>>greater body, the regoliths may from time to time become satellites of the main object. And vice versa.

  • Steve Garcia

    I am going to come back to this.

    Dennis said, “Why wouldn’t an ablative airburst event produce shocked grains?” way back on July 9, 2014.

    I don’t think I addressed the real reason for this not being possible. And that real and simple reason is that only a hypervelocity impact has the energy density to create shocked grains.

    An ablative airburst isn’t really an airburst, anyway.

    First off, what look as like an explosion is in reality the vaporization of a larger cross sectional area of ablated front-side of the object coming in. It breaks apart along some internal weak fissure, making two or more objects with a larger cross section for a moment. It LOOKS like an explosion, but it isn’t – no more than the ablation and vaporization of the smaller particles sloughing off are – just compounded by MORE particles due to the break-up of the larger body.

    So the term airburst is descriptive but not correct. It flares but only in the way a fireworks rocket sprays particles out and ignites them – the ignition of them is a fire but not really an explosion. If the particles were not distributed outward, the “explosion” of the rocket would seem small and not large.

    You can quibble about how an explosion is an uncontrolled rapid expansion, but the truth is that not all rapid expansions are explosions. And if you want to call the “airburst” an explosion, then you have to call the entire ablation from the moment it enters the atmosphere an explosion – each and every particle ablating and vaporizing incandescently. Which makes the luminous tail we see. Is the tail itself an explosion? If it is then the airburst is. If it isn’t, then the airburst isn’t.

    The continuing ablation and the airburst are the same process, just a matter of scale.

    The other – and main – point is that the energy density simply isn’t enough in an airburst, even if it WERE an actual explosion. Regular REAL explosions on earth – TNT, etc – are not capable of creating shocked materials, either.

  • Your fertile imagination is pretty good Steve. But supercomputer simulations done at Sandia Labs describe something else.

  • In point of fact Steve the impact site where the Libyan Desert Glass was produced shows none of the geomorphology of a kinetic impact crater. The only evidence there of a hypervelocity event is the glass of melted Sahara sand, and interestingly enough, shocked quartz grains.

  • Steve Garcia

    Dennis –

    Sandia Labs – another worshipful take for you on the Bos.

    You also don’t specify what supercomputer model. And models are not reality, or haven’t you heard? Do super computers leap tall buildings in a single bound? Even with Crays or whatever, the code still has to be right and TRUE TO REALITY. GIGO, you know.

    Sorry, Dennis. You keep on making vague, generic statements that have no specificity with which to respond. “Your imagination” – on what points and what point is it that you are making in response? Bos is better than me? Who knows?

    The man doesn’t do science, only plays with computer models, not empirical evidence.

  • Steve Garcia

    What does the Libyan glass site have to do with what I was talking about? Nothing.

    That Bos SAYS that was an airburst doesn’t make it an airburst. There are several other candidate hypotheses by others, and we’ve been over that ground before. Yaddah yaddh yaddah. . . Bos this and Bos that. All he has is his model.

    The fact that you like the Bos and his stuff doesn’t make it true.

    Dennis, I respect your opinions, I do. But Bos I don’t. He is a pretty boy poster boy who does everything for attention and grant moneys. He does science by TV shows.

  • Steve said:

    “Sandia Labs – another worshipful take for you on the Bos.”

    Hmmm…, yeah, since your opening sentence is a small minded, and meaningless, piece of personally insulting ad hominem drivel, we can see where you want to go with this, and that you aren’t prepared so say anything intelligent about the actual science, or the institution I’ve just cited.

    But just to be clear just exactly what caliber of institution you’re pissing on here, Sandia Labs is a very well respected, and major national laboratory operated by the US Department of Energy, and the National Nuclear Security Administration. They have also done as much work regarding impact science as NASA’s Ames facility.

    That’s no cult, or place of worship.  But if seeking out good, reliable sources of scientific, or experimental data, and then trusting the quality, and truth of that data based on the impeccable world wide reputation of the institution providing it, is to be counted as “worshipful” then ok, I’ll pray at that alter.

    “You also don’t specify what supercomputer model.”

    Model name: Red Storm;

    Owner/Operator: US Department of Energy, and the National Nuclear Security Administration’s Advanced Simulation and Computing Program.

    Manufacturer: Cray Inc;  Cores: 26,544; Linpack Performance (Rmax) 101.4 TFlop/s; Theoretical Peak (Rpeak) 127.411 TFlop/s

    “And models are not reality, or haven’t you heard? Do super computers leap tall buildings in a single bound? Even with Crays or whatever, the code still has to be right and TRUE TO REALITY. GIGO, you know.”

    Really? You’re gonna piss on the quality of the coding used without even having the remotest kindergarten clue what that coding actually consists of, or even what kind of computing platform it was written to run on?

    I wonder, just how “true to reality” do we expect the imagination of an armchair researcher to be when the “garbage in” is based solely on internet searches? And never mind that most of that “garbage in” is limited to abstracts only, or stuff that’s not pay walled.

    But in the context you’ve given above, and in comparison with the computational capabilities of Sandia’s Red Storm, I’m pretty sure the mere imagination of an armchair researcher, and self proclaimed authority on all things relating to impact science is gonna trip over the curb, and fall flat on its face as soon as it tries to leap.

    “Sorry, Dennis. You keep on making vague, generic statements that have no specificity with which to respond. “Your imagination” – on what points and what point is it that you are making in response? Bos is better than me? Who knows?”

    What vague, and generic statement? You made some very specific, and authoritative, proclamations regarding just exactly what you think happens during an airburst that does not jibe with any peer reviewed science on the subject. And without citing a single piece of supportive, peer reviewed literature. You also proclaimed conclusively that an airburst could not produce shocked grains without providing a single piece of actual supportive science on the subject.

    I answered with a poster regarding science done by a major national lab that produced compelling evidence to the contrary, and implied that your self assumptive expertise, and imaginary visualizations of airbursts, and impact physics aren’t even close to the mark. And all you could come up with for a response is a personal ad hominem attack.

    Since you, yourself have never done, or published, any real science on the subject of airbursts, or impact physics, then without any Curriculum Vitae to the contrary it’s fair to say your knowledge of the subject is limited to what can be gleaned from internet searches. And that the authoritative, and descriptive visualizations you come up with of what happens during an impact event are based solely on self-assumptive expertise. AKA your own personal imagination.

    “The man doesn’t do science, only plays with computer models, not empirical evidence.”

    Yeah, so apparently, in the world according to you, taking a half dozen vehicles, and a whole slew of other scientists on an expedition to an extremely remote, and trackless, location in the middle of the Sahara to collect geologic specimens of the LDG, and to do a new geologic map the site based on modern hi resolution GPS instrumentation is just another joyride to a choice vacation spot in the desert.

    Point of fact:

    Every impact simulation done at Sandia Labs by their advanced simulation and computing team is based on actual expeditions, and  geologic field work to the site of the impacts being simulated. Nobody gets to “play” with a 90 million dollar, DOE owned supercomputer.

    As for who’s the better scientist, you or a veteran physicist, and physics professor, with a CV as long as your arm, and never mind that he’s extremely skeptical of the YDIH, I’m afraid you’ve got nothin’.

    “What does the Libyan glass site have to do with what I was talking about? Nothing.”

    Since the LDG has ET chemistry in it, and shock metamorphism was found to part of the event, yet without any trace of crater geomorphology, the LDG remains the best known candidate for an airburst that reached the ground. And it proves that contrary to your personal assumptions, and oh so authoritative proclamation, the direct hypervelocity impact of a solid object is not necessary for the production of shocked quartz grains.

    “The fact that you like the Bos and his stuff doesn’t make it true.”

    Likewise, your low personal opinion of him, does not falsify the science he’s done.

    “Dennis, I respect your opinions, I do. But Bos I don’t. He is a pretty boy poster boy who does everything for attention and grant moneys. He does science by TV shows.”

    Point of fact: None of the peer reviewed works in Boslough’s CV has ever been funded by a TV production.

    You on the other hand, are nothing more than an armchair researcher, internet gadfly, and prima donna who does not do any real science at all.

     

     

  • Steve Garcia

    Compared to Argonne, Lawrence Livermore, Lawrence Berkely, and the nearby Los Alamos, Sandia is second level of the national labs.

    As to me citing sources or not, I clearly let people know when it is my opinion. You,, on the other hand, look at your comment of 2:58 yesterday, Dennis. No reference even to one of my points, much less a resource of your own. How is someone supposed to respond to a comment which lacks all specificity?

    And “Your fertile imagination…” and “your self assumptive expertise, and imaginary visualizations” – those isn’t an ad hominem argument? The pot, Dennis, is as black as the kettle.

    As to they assessment of ablation, I DID get taht from peer reviewed papers. Everything I know about the ablation of meteors came from such papers. They, in fact, amazed me when I read them. Having worked in R&D with some materials that ablate when used on rocket nose cones (though my application was much more mundane), I had some exposure to the entire concept, and was glad that I was able to expand my knowledge about ablation. I was able to follow those descriptions quite well, and I retained it. If you want to look it up, find my comments from just after the Chelyabinsk event. I repeat: None of what I said is imagination, fertile or not. If I lost you or you couldn’t keep up, my apologies. Go to Google Scholar and enter “ablation meteor”. That is what I did.

    I don’t understand why you feel a need to diminish concepts from others here. You’ve had your share, and I’ve supported them at every turn – and when I had particular points that I thought might be wrong, I’ve addressed them civilly. Ed was running around hollering about your own imagination about the ablated hills in the SW desert, and I supported you all along.

    Me: “The fact that you like the Bos and his stuff doesn’t make it true.”

    You: “Likewise, your low personal opinion of him, does not falsify the science he’s done.”

    I couldn’t agree more! We can both have our opinions! And we are free to disagree! I love it! 🙂

    When you yourself have your name on peer reviewed papers, let me know, though. I am a fan of other scientists than your favorites. BIG DEAL.

    The LDG stuff, as I saoid, we’ve gone over before, and we don’t need to go into it again. There are SEVERAL peer reviewed hypotheses on the LDG, and ONE of them is Bos. You are ignoring the others, and that is your choice. Those other papers do NOT agree with the Bos. Will you take it up with THEM? An ablative event? So he says. They say differently. The entire subject is up for grabs, up for discussion, and there is NO definitive explanation for them. While it is up for grabs, all sides can assert anything they want – and will have SOME of the evidence to support them. I tend to side with the tektite side of the argument, though I don’t think THEY have it all, either. To me it is all open questions.

    The Bos has his “miracle height” (just above the ground) airburst that is too close to cherry picking (as to the height) for my tastes. If we all get to pick our facts and parameters, science flies out the window. That same airburst if not at that height will not produce the results he loves – and which the TV shows love, too. It’s like people basing projections on worst case scenarios, and then, when later discussing them, fail to inform the audience that “the worst case scenario” means about a 1% chance. I base that on 95% certainty being the scientific statistical norm for likelihood. Even most of the 2.5% o either end is not “the worst case scenario.”

    I also base it on an object careening toward the ground at perhaps 3km/sec at the end of its flight which began at about 20 km/sec as it entered the atmosphere, and then choosing a ten-meter vertical window of that path as the Goldilocks height for one’s model. At an angle of 45° that 10-foot window is about 14 meters long. That object is in that window for 14/3000 seconds – about 0.005 seconds. THAT is Bos’ cherry picking. Choose your own exact numbers, but any way you look at it, the odds are less than 1%. My result was about 1/200th of a second. What is yours?

    Bos has never been paid by a TV show?! Are you sure about that? I’ve got 100 bucks that says he has. If he hasn’t negotiated for money, someone didn’t tell him the reality of those shows.

  • Steve Garcia

    From the Sandia pdf:

    “…a 120-meter asteroid entering the atmosphere at 20 km/sec (effective yield of about 100 Megatons) breaks up just before hitting the ground.”

    One does assume that by “Sandia” it means Bos himself, since he is their expert on this. Though he included his own “contact” information, he does not clearly identify himself as the author.

    …But just where do I begin here?

    1.) Let’s start with Tunguska, whose estimated size was just about that 120-meter size. Estimates frame this size, being between about 60 meters and 190 meters. That object, by the best estimates, was an asteroid/meteroid.

    Gene Shoemaker (1983) estimated Tunguska’s blast to be 10-12 megatons – about 10% of Bos’ estimate. How does Bos explain this ten-fold discrepancy?

    Though Tunguska, of the same size as Bos’ asteroid, exploded at an estimated 5-10 km, Bos says his would make it almost all the way to the ground. How does he explain this discrepancy?

    2.) Bos talks about ablation of the materials on the ground. I was talking about ablation in the passage through the atmosphere. Two very different things, though because he chose his special height he got to maximize the velocities of the blast wave. But he DID call it a “break up”, to his credit. I agree – airbursts ARE breakups, not explosions of internal fuel, as we normally think of explosions.

    At the same time, the ablation (that brought on the break up) does not begin at that height. The ablation began the instant that the air ahead of the asteroid/meteor entered the atmosphere was compressed and heated. This compressed and heated air is what causes the ablation along the atmospheric path. And THAT ablation begins to reduce the size of the object, as it loses material for km after km, second after second.

    Bos does not explain if the 110 megatons is based on the “before” size (at entry) or the “after” size of the asteroid (at his airburst height). THIS is cogent to all arguments of energy, and thus, to his results in his model.

    2.) With Tunguska (the same size range and whose average estimated size is almost EXACTLY Bos’ size) airbursting at 5-10 km above the ground, how does Bos explain that HIS asteroid would make it essentially all the way to the ground?

    – Did he also estimate the DENSITY of the object to be higher than Tunguska?

    If so, how does he justify that density setting in his model?

    Similar object densities and sizes SHOULD yield similar airburst heights and similar megatonnage yields.

    Yet Bos has his object doing what the only REAL WORLD object of that size has NOT done – make it below 5 km.

    How does he manage that?

    4.) In such an unknown (and therefore unspecific) event as this, and with several main parameters that would affect the outcome, the normal scientific approach – especially for a MODEL – would be to create a matrix. Each of the main parameters for the matrix would be stepped up one by one (by some amount that would give discernably different results), while the other parameters would be held constant. Thus a matrix of possible outcomes would be output and recorded.

    Those variable parameters should in this case include size, density, and velocity.

    The fixed constants should include atmospheric density curves and the altitude of the ground.

    The above should yield varying heights of the airburst for each run. At least SOME of those should yield results similar to Tunguska – a 5-10 km airburst. If they do not, then it SHOULD be “back to the drawing board.”

    I would fully expect that Bos DID such a matrix.

    I would also fully expect that Bos would PUBLISH the various results of those individual runs of his model, so that the world at large could SEE his OTHER results.

    So, my question is this:

    Did Bos publish any other results? Such as an airburst at OTHER altitudes?

    One assumes in THIS case that Bos set the altitude to that of the Libyan Glass. But he should have had many runs of his model that basically are generic as to ground height.

    In other words, his PRIMARY airburst model should be INDEPENDENT of ground altitude.

    Then, when he applies it to the LDG site, the altitude MAY or MAY NOT give him those results. Certainly MOST of his matrix will NOT give the perfect height for his desert glass ablation.

    Where are THOSE OTHER results from his model? All he shows us is ONE.

    And – miracle of miracles – that one happens to show exactly what Bos wants us to see.

    …I have to think that the ghost of Richard Feysman would cast a suspicious eye on Bos’ ONE result.

    …As to matrices such as I just described, I have practical experience running experiments for a matrix like this. Parameters were known, but their compined outcomes were confusing, so a matrix was created – and that matrix was successful in identifying how the results could tell us in retrospect what had happened in the quite complicated process we were running.

    Is any of that in peer-reviewed journals? No. Was it science? Yes. Was it real-world? Yes. Did we do good science in creating the matrix? Absolutely.

    …Did Bos make such a matrix. Oh, I’d bet on that one! One that he hasn’t shared yet. One that would show how unlikely his results are, is my guess. Why do I bet against it? Because if he had done it and it HELPED his arguments, he would have published it and would be shouting it from the ramparts.

    Dennis, all of this is SOLID reason to doubt Bos’ miracle Goldilocks height.

  • Steve Garcia

    Miss-sttated sentence:

    WRONG: “Yet Bos has his object doing what the only REAL WORLD object of that size has done – make it below 5 km.”

    Should read:

    RIGHT: “Yet Bos has his object doing what the only REAL WORLD object of that size has NOT done – make it below 5 km.

  • George Howard

    Fixed.

  • George Howard

    Hate to interrupt your spat, gentlemen, but I am looking for help finding the publication that prompted this post.

    If anyone has “Long-term stabilization of deep soil carbon by fire and burial during early Holocene climate change” Erika Marin-Spiotta et al., I sure would appreciate you sending it to me!!!

  • Steve said:

    “Compared to Argonne, Lawrence Livermore, Lawrence Berkeley, and the nearby Los Alamos, Sandia is second level of the national labs.”

    While that statement may be true, it is irrelevant to any assessment of the validity of the science done there, or the quality of the data produced by them. And it had better be. Since they’re among the folks who’re tasked with keeping a handle on the nuclear security of this country the quality of the work they do has to be above reproach.

    “Me: “The fact that you like the Bos and his stuff doesn’t make it true.”

    You: “Likewise, your low personal opinion of him, does not falsify the science he’s done.”

    I couldn’t agree more! We can both have our opinions! And we are free to disagree! I love it!”

    Yeah, after putting up with Ed’s mindless, and stupid ad hominem shit for years I’ve developed an extremely low patience threshold for it’s use in any discussion at all. And no matter who’s being pissed on, or if they really are an asshole. And admittedly, Bos is that sometimes.

    In point of fact though, our personal opinions of the character of anyone is perfectly irrelevant in any logical scientific debate. And should never be included in any attempt at rational conversation.

    From Wikipedia:

    An ad hominem (Latin for "to the man" or "to the person"), short for argumentum ad hominem, means responding to arguments by attacking a person’s character, rather than to the content of their arguments. When used inappropriately, it is a fallacy in which a claim or argument is dismissed on the basis of some irrelevant fact or supposition about the author or the person being criticized.

    Abusive ad hominem usually involves attacking the traits of an opponent as a means to invalidate their arguments. Equating someone’s character with the soundness of their argument is a logical fallacy.

    We’ve also seen an awful lot of Ad hominem circumstantial in your remarks regarding Boslough.

    Ad hominem circumstantial points out that someone is in circumstances such that they are disposed to take a particular position. Ad hominem circumstantial constitutes an attack on the bias of a source. This is fallacious because a disposition to make a certain argument does not make the argument false; this overlaps with the genetic fallacy (an argument that a claim is incorrect due to its source).

    “And “Your fertile imagination…” and “your self assumptive expertise, and imaginary visualizations” – those isn’t an ad hominem argument? The pot, Dennis, is as black as the kettle.”

    No, those aren’t ad hominem at all. To say that one has a “fertile imagination” is no slight. And when a self taught individual presumes to a high level of authority on a given subject without academic credentials that back it up, that is in fact, “self assumptive expertise”. And every time a person uses his own mind to visualize something based on something he’s read somewhere it’s nothing more than an “imaginary  visualization”. And no matter how smart, or knowledgeable, the person doing it is, it does not begin to compare with the kinds of simulations that can be produced on a supercomputer like Red Storm. That’s why 90 million dollars is a fair price to pay for a machine like that.

    There is no ad hominem in pointing those things out as observable facts. And none of them trumps real science, or experimental data.

    “The LDG stuff, as I said, we’ve gone over before, and we don’t need to go into it again. There are SEVERAL peer reviewed hypotheses on the LDG, and ONE of them is Bos. You are ignoring the others, and that is your choice. Those other papers do NOT agree with the Bos. Will you take it up with THEM? An ablative event? So he says. They say differently. The entire subject is up for grabs, up for discussion, and there is NO definitive explanation for them. While it is up for grabs, all sides can assert anything they want – and will have SOME of the evidence to support them. I tend to side with the tektite side of the argument, though I don’t think THEY have it all, either. To me it is all open questions.”

    Sometimes it helps to put pubs like that in chronological order. The Sandia Labs expedition to the LDG, and Boslough’s work there is  just the latest, most thorough, and technologically current, examination of the LDG site to date. And the only one to employ a supercomputer to get a plausible picture of what may have happened there. If you had bothered to actually read up on it you’d know that it also answered all of the previous work done there.  However, if you still want to say the LDG is merely tektites from a conventional impact, then you’ll have to explain the complete lack of a crater. And since the chemistry of the LDG  is a perfect match for the sands of the Sahara where it’s found, but spiced up with little inclusions of meteoritic residue, you can’t say it was thrown there by an impact that happened somewhere else.

    Reality check:

    Your distaste for Boslough obviously goes to his prominent, and very vocal, skepticism of the YDIH.

    And since much of his work flies in the face of your own cognitive bias, and since he’s such a vociferous opponent of the YDIH,  you’ve never bothered to actually read any of Boslough’s work on airbursts, or impact physics. This is evidenced by your utter lack of knowledge regarding what computer was used for the sims, or the exact nature of the coding used. Further evidence that you’ve never actually bothered to read up on any of his work is provided by your claim that,

    “The man doesn’t do science, only plays with computer models, not empirical evidence.”

    So apparently you’ve got a warped view  of what constitutes “empirical evidence”. But the simple reality is that every single impact structure, or event, Boslough has ever published on involved going to that place personally, and doing his own field work. Whatever else he might be, he’s no desk bound computer geek, or lab rat.

    We should note here though that the YDIH team does not seem to have as low an opinion of his work on airburst phenomena as you do. This is evidenced in Isabel Israde-Alcántara et al’s proposal in their PNAS paper titled Evidence from central Mexico supporting the Younger Dryas extraterrestrial impact hypothesis that the YD impact event was characterized by multiple large airbursts witch accounts for the lack of a crater. For them to prove that idea would be a wonderful example of academic poetry, and a fitting karma for Boslough after all the shit he’s heaped on the YDIH.

    The Bos has his “miracle height” (just above the ground) airburst that is too close to cherry picking (as to the height) for my tastes. If we all get to pick our facts and parameters, science flies out the window. That same airburst if not at that height will not produce the results he loves – and which the TV shows love, too. It’s like people basing projections on worst case scenarios, and then, when later discussing them, fail to inform the audience that “the worst case scenario” means about a 1% chance. I base that on 95% certainty being the scientific statistical norm for likelihood. Even most of the 2.5% o either end is not “the worst case scenario.”

    Yeah, if you’d ever actually bothered to read those papers you wouldn’t be using terms like “miracle height”, or “cherry picking”. And you’d understand that the Red Storm sims all show the object beginning to explode the moment it enters the atmosphere. And that the speed of the expanding explosion closely matches the speed of the object’s entry, so you get a moving explosion along a line instead of a point detonation at some “miracle height”. And you’d also know that if you change any of the variables such as impact angle, velocity, or object size, and density, you get a completely different result. What those sims show very clearly is that no two impact events are the same.

    The true test of any computer model, or simulation though comes when it gets compared to observed reality. And that same hydrocode model was successfully used to accurately predict the consequences of SL-9 before the first fragment hit Jupiter. And when the model is run with the observed parameters of the Chelyabinsk event you also get a match for what happened there.

    “Bos has never been paid by a TV show?! Are you sure about that? I’ve got 100 bucks that says he has. If he hasn’t negotiated for money, someone didn’t tell him the reality of those shows.”

    Please pay better attention. I did not say that he’d never been paid for an appearance on a TV show. What I said was that none of the science he’s published was funded by a TV show. In fact, since he went to work for Sandia, they’ve bankrolled the science he does. That’s why you see them named first in the credits of all of his papers, and posters.

     

  • I do believe this is it George. I’ve got it on Dropbox. If the link is a problem I can email it to you.

    Long-term stabilization of deep soil carbon by fire and burial during early Holocene climate change.

    By Erika Marin-Spiotta et al.

  • Steve asked:

    1.) Let’s start with Tunguska, whose estimated size was just about that 120-meter size. Estimates frame this size, being between about 60 meters and 190 meters. That object, by the best estimates, was an asteroid/meteroid.

    120 meters for the Tunguska object is waaay oversized, and out dated. What’s your source for that estimate?

    Gene Shoemaker (1983) estimated Tunguska’s blast to be 10-12 megatons – about 10% of Bos’ estimate. How does Bos explain this ten-fold discrepancy?

    The great Gene Shoemaker led the way. But 30 years after the fact “pioneer” is just another way of describing a beginner who didn’t have anyone’s shoulders to stand on. Gene was still doing many of his calculations on an old fashioned slipstick back in ‘83. And much has changed since then in the field of impact science, and related physics. And advances in computer science have vastly exceeded even the most fanciful predictions of the science fiction writers of 30 years ago.

    This article might give you an answer though: Sandia supercomputers offer new explanation of Tunguska disaster 

    Though Tunguska, of the same size as Bos’ asteroid, exploded at an estimated 5-10 km, Bos says his would make it almost all the way to the ground. How does he explain this discrepancy?

    It’s not  clear where you come up with “Bos’ asteroid”, or what makes you think anyone’s saying they were both the same size, or what makes you think there’s a discrepancy in what’s been described for the two places.

    But the “discrepancy” you speak of exists only in your apparent misunderstanding of the current state of the science relating to the LDG, and Tunguska. Since he’s been to, studied, and published papers, on both the LDG, and The Tunguska event, (Gene Shoemaker never got a chance to put boots on the ground at either of them.)

    But in fact, in the Sandia/Boslough work on those places they can be seen as two very similar events differing only in scale. Tunguska can be thought of as a threshold event where anything bigger would have produced a fireball that reached the ground like the LDG event. And Chelyabinsk added one more event to that scale that’s just a little smaller than Tunguska. You could even step up that scale a bit, and say that anything bigger than the LDG object probably would’ve punched a hole in the ground making a crater.

    See: Impact Melt Formation By Low-Altitude Airburst Processes, Evidence From Small Terrestrial Craters And Numerical Modeling.  H. E. Newsom, and M. B. E. Boslough

    I’ll have a little more tomorrow. I’m waiting for some other stuff that’s behind a paywall to be emailed to me.

  • George Howard

    Thanks, Dennis!

  • Steve Garcia

    “Since they’re [Sandia]among the folks who’re tasked with keeping a handle on the nuclear security of this country the quality of the work they do has to be above reproach.”

    Actually, your argument works both ways. Perhaps doubly so. Thisis an appeal to authority – usually one of the last bastions of a debater who has nothing to offer. In addition, Bos is not working on that arsenal.

    For those who dont’ know it, the National Labs have been for some time been set loose because they don’t get the massive funding they once did, and they have to compete for money and grants, just like every other research facility in the country. I have that first-hand from someone who worked there until not so long ago.

    Thus, every research project is a stand-alone project. So, you can’t let Bos lean on the arsenal protection for his work.

    “In point of fact though, our personal opinions of the character of anyone is perfectly irrelevant in any logical scientific debate. ”

    Dennis, I agree with that completely. Where I’ve done so I have tried to aim it at their professional behavior and work. If I’v crossed the line, it was the excitement of the moment perhaps. Apologies where that has happened.

    As to “your fertile imagination”, Dennis, you know sa well as I do that it wws meant as an attack on my person as opposed to my arguments.

    Even this is ad hominem, in that it does not address my technical points one iota:

    “And when a self taught individual presumes to a high level of authority on a given subject without academic credentials that back it up, that is in fact, “self assumptive expertise”. And every time a person uses his own mind to visualize something based on something he’s read somewhere it’s nothing more than an “imaginary visualization”.”

    You assume that because I don’t have Bos’ credentials that his thinking is superior to mine, but you don’t address the POINTS I’ve made – only attacking my lack of credentials.

    In addition, once a degree is earned, any research or thinking done by a credentialed person IS a visualization of something.

    In adding “something that he’s read” you apparently assume somehow that I don’t have the capacity to understand the papers in the factual vein in which they are published, that I take such papers and run off into the wild blue yonder with crazy ideas.

    Are we to think then that everything you’ve read and to some degree understood is of the same calibre?

    I certainly don’t think that of you. I RESPECT your input and opinion and take on things. In fact, much of me commenting here is INTENDED to ASK for input from you and others. Like I said (and Jim caught it), I think out loud here.

    NOTHING I say on here is presumed to be the final answer on ANYTHING. I am not THAT stupid. 🙂

    IOW, I value your input – but ON THE POINTS, PLEASE. I’d very much your tearing my POINTS apart and telling me exactly where I am going wrong. I ASSUME I am going wrong sometimes. Trust me on that. Humility is the road to learning. But in learning, it is necessary to be able to put what one has learned into his own words. If sometimes that re-stating has gone afield, it is good (and I think necessary) to have other people to help put one straight.

    Bos’ opposition to the YDIH affects my opinion of him? NOT AT ALL. Three points here:

    1.) If the YDIH is wrong I don’t want any part of it. So far, to my grasp of things, the YDIH has moer going for it than the opposition has against it. I have yet to see ONE attack on it that is not misguided and biased in the extreme. If you’d observe the attacks on the YDIH with the same fervor you argue against me, you might see that yourself.

    2.) Bos hasn’t said squat about the YDIH that is IMHO worthy of a good scientist’s rebuttal. Mos tof his participation was diverted into “LOOK AT MY WORK ON THE LDG!” instead of addressing the YDIH impact physics.

    3.) On the LDG my opinion of Bos is based solely on his Goldilocks airburst elevation, which I went into some depth to point out. Nothing in that has ONE WHIT to do with the YDIH.

    …more later – I have to run…

    But, Dennis, I assure you that I want to see all of this intriguing puzzle worked out as much as you do. In the middle of it – like in the middle of any scientific mystery – the facts are muddled up into a jumble and people pick out different evidence to focus on and get different answers/interpretations by leaving out stuff that they can’t focus on just then.

    I don’t expect that either of these mysteries will be solved any time in the next 10 or 20 years. After all over 1,000 papers have been done on Tunguska over a period of about 80 years, and they are only now (I think) getting somewhere on it.

    As I learned in complex problems in R&D, it takes TIME to even find the right QUESTIONS to ask. And it takes any number of iterations of questions to zone in on what those right questions ARE. THE right question might be completely hidden from view for a very long time.

  • George Howard

    Dennis, The Bos has been extraordinarily hurtful to our research. Among other shameful examples he led the quiet but successful effort to remove the NOVA episode from their website. That’s one step from book burning. You may have some intellectually nuanced defense of, or admiration for, the dude. But in my book he is an intellectual bully and ideological terrorist willing to attack — and destroy — that which offends him. Just sayin’

  • I’m not so damned impressed with him on a personal level either George. But the simple fact remains that there’s a very good chance that the YD impacts were in fact dominated by multiple large airbursts. That’s why there’s no crater to be found. That being said, it would not make much sense to throw out perfectly good bath water with the baby just because the nasty little shit won’t quit pooping in our house.

    It’s clear that any geomorphology that results from the kinds of very large airburst events depicted in those supercomputer simulations would produce dramatically different kinds of planetary scarring from the standard model, uniformly round, impact craters we’ve come to expect, and that we see on the Moon, and Mars. So we are talking about a completely new, and updated, version of the so called “full suite” of impact markers. And of acknowledging that thanks to our unique atmosphere impacts events here are vastly different from what we thought, or from anywhere else in the solar system.

    The thing is, the only way to get a handle on just exactly what that new set of geologic clues might consist of is to learn to understand what Red Storm is showing us in those simulations even better than the guy who coded that airburst impact model in the first place. The accuracy, and reliability, of that impact model was demonstrated when it accurately predicted the effects, and energies, of the SL-9 fragments months before they hit Jupiter. So no matter what we might think of it’s author, his physics have stood the test.

    And very the idea of proving our case using the life’s work of our biggest skeptic, and detractor, rings a sweet bell in my soul.

  • By the way, they may have removed the NOVA episode from the website but they didn’t toss it completely. I just watched it again the other day on our local PBS channel.

  • Steve Garcia

    Dennis –

    Thanks for all that last longer comment. We are mostly on the same page, and I want you to know that. YES, the cratering that is now accepted is only a small suite of the overall possible markers possible. You’ve said that before, and I agree completely. convincing the uniformitarians of the full variety of possible impacts is going to be a centuries-long effort, and they will have to be dragged, kicking and screaming, on every new type, into the reality of impacts.

    And ABSOLUTELY, the Earth’s atmosphere makes HERE the place where impacts are DIFFERENT. As Chelyabinsk and Tunguska show us, it is TOUGH to get an impactor all the way to the ground. Hell, Chelyabinsk didn’t even get within 20 km of the surface. From those two it is my take on it that we are well protected against any but the really large ones – perhaps 200 meters and up.

    Do small ones get through? Yes. And THAT is an avenue of research that intrigues me. How do some leave 6-inch meterites when most don’t – and when Chelyabinsk barely made it, leaving only a 1-meter or so chunk? Did they ALL start out that large? Probably not. We’ve seen in the Carancas event in Peru that a relatively small one can make it to the ground.

    …That same atmosphere makes it all the more UNLIKELY that an impactor will be a civilization destroyer. But unlikely doesn’t mean impossible.

    Science without an open mind is stupid science. Science without skepticism is also stupid science. Self-satisfied science is the stupidest science of all. I like to think that we here are a happy middle ground – skeptical yet not closed-minded, like Bos and the Daulton gang.

  • Steve Garcia

    George –

    Wow, I had not even HEARD about Bos getting that episode pulled. Shades of Adolf, like you said.

    It simply boggles the mind, doesn’t it?

    The guy is a bigger dick than even I had known. But I honestly wouldn’t put it past him. The guy got a little attention and so he thinks he is God’s gift to science. It’s all about “ME ME ME ME ME…”

    Shades of Bill Nye, the Science Guy – a vacuous nobody who can’t do real science himself and coined a catchy moniker to draw attention to himself.

  • Steve Garcia

    Dennis –

    In tersms of non-standard cratering events, I can’t recall ever seing you reply to anything about the Rio Cuarto, so I’d invite you to look at those.

    And when you do, follow the axes of those 10 craters for about 200 km farther to the SSW. Along that line you will find many hundreds of MORE such markers.

    At this time only the 10 main ones NNE of the city of Rio Cuarto are acknowledged as impact craters (and not without controversy THAT!).

    Peter Schultz was the main pusher of getting those accepted into the impact database, from what I gather.

    But those OTHER hundreds along the same track imply that HUGE multiple impact events have occurred. Are they all actually impact craters? They are FAR deeper than the Carolina bays, so that argues in their favor. They DO have some NNE-SSW end differences, similar to the CBs, but being so much deeper they SHOULD be more easily defined as impacts.

    And what is the standard explanation of the Rio Cuarto elongated ellipses? You got it – aeolian (wind-blown). The uniformitarians throw the wind at everything, and then, having “explained it” so that they can sweep it all under the carpet, they ignore it. And when someone comes along later, they say, “Oh, we dealt with that YEARS ago. Those are nothing but wind-blown ellipses.” Sound familiar, anyone?

    And this EVEN THOUGH the impact database includes the TEN as impacts. Along that same track. With the same basic elongation ratios. With similar depths. With CB-like overlaps no less!

    It would be LOVELY to find LIDAR maps of those areas.

    Check them out on Google Earth. There are FIELDS of them.

  • Jim Coyle

    http://malagabay.wordpress.com/2014/11/30/the-great-greenland-snow-job-04-gripping-the-hockey-stick/ Some more info on arctic and antarctic ice findings. Does anyone have Al Gores e-mail address? I’d like send him a copys for s—s and giggles.

  • Yeah Steve,

    I’ve been arguing for large cluster events like that for an awful long time now. And Rio Cuarto is the place I like to throw back at folks who tell me such an event would be “highly unlikely”. But since there is both, meteoritic materials, and shocked quartz grains, to be found there the whole Aeolian thing the gradualist folks like to blame them on does not stand up. They are in fact confirmed as impact craters.

    I don’t  know how many folks here have done any impact experiments with high powered rifles. But I am privileged  to be able to use nephew’s .50 cal. Barret to do a few supersonic shots at various angles. We used differently loaded rounds to simulate different impact energies. And based on that experience I can tell you that the shape, and geomorphology of the Rio Quarto craters looks consistent with objects hitting the ground at a very low angle, and something like twice the speed of sound. Which is enough to account for both the shapes of the depressions, and yet still enough energy to account for the shocked materials found there.

    But since all that meteoritic material probably would’ve hit the upper atmosphere at somewhere in the neighborhood of 20 kilometers per second the fragments that finally made it to the ground had to have given up an awful lot of energy in the atmosphere on their way down. So there would’ve been some major atmospheric stuff going on with the impact event that did that. Think of Chelyabinsk, or Tunguska as lone firecrackers  compared to a whole barge load of them. And it doesn’t take much imagination at all to see Rio Quarto as a good example of a geologically recent city killer.

  • Steve Garcia

    Dennis, I could hardly agree with you more on the Rio Cuarto craters.

    Not only that, but your velocities re probably not that far short of the impact velocities at Rio Cuarto, given the apparent low impact angles. Such angles argue for long atmospheric paths, which then imply long deceleration times. That all implies at least two things: High likelihood of atmospheric break-up (ala Chelyabinsk) and relatively low impact velocities.

    So, IMHO your Mach 2 velocities should be only a few mach too low – and thus fair analogs.

    While Rio Cuarto itself would likely rank – as you say – as a city-killer, it is my lay estimate that as a regional event (though a LARGE one), it would not pose BY ITSELF a global civilization killer. Civilization COULD perhaps survive, even though it might be a tough recovery.

    Did you go look at the other several hundred impacts farther SSW? Some are plowed over and still visible, so LIDAR might show up perhaps another hundred or two. I have GE images if you’d like to see them.

  • Since you haven’t said anything new in years Ed, and even now don’t have anything to say beyond talking trash, and hyping your own poorly writen, self-referenced, and self-published, book your opinions are completely errelevant.

  • P.S. Ed said: “Your experiments have absolutely no relevance to hyper velocity impacts.

    Reality check:
    Of course not, they are only relevant to barely supersonic, and below.

    Not even one of the recovered fragments of the Chelyabinsk object were still a hypervelocity object by the time they reached the ground.

  • Ed said “Your comment demonstrate your rather entirely complete ignorance of Gene Shoemaker’s life and and his work.“

    Your continued failure to provide any useful, or varifiable, information whatsoever beyond personal ad hominem insults is typical of you Ed. And this kind of childish fifth grade behavior is in fact the very reason George had to boot you from the Tusk.

    So what can we deduce about your own level of ignorance from the painfully obvious fact that you never learn?

  • Steve Garcia

    Dennis –

    The Rio Cuarto craters (however many of the toal regional elliptical crater-like features are accepted as actual impacts) can for the moment be positioned as one extreme shape of crater. Round impact craters represent the opposite pole of the range of crater-shaped impacts.

    We seem to be in a world where the experts on these shapes can’t accept much of anything but circular craters, which doesn’t make much sense. “YES, to all those that ARE circular”, they say, and no to any that are not.

    I would argue the opposite – that Rio Cuarto changed everything. I ask why, now that now that elliptical shapes are known to be craters, we have we gone over 20 years without finding any more?

    Elliptical shapes should be looked for in the geomorphology of the planet. If there is ONE Rio Cuarto event (even if RC would have been ONE crater, not 10), then there must be more. And the ellipticity of them is probably going to be different than Rio Cuarto. Given the extreme elongation there, one would expect the others to be less elongated.

    Somewhere along the way the intermediate elliptical shapes must be found and accepted.

    Rio Cuarto’s low angle of incidence does argue strongly for a long path in the atmosphere, both in kms and also in time. Longer deceleration means lower ground impact velocity. That SHOULD ALSO be a clue as to the different energy transfer to the target, which should also argue that the thinking that dictates all craters to be circular needs to be re-thought.

    In addition, if RC craters are low-velocity craters, then the other elliptical craters – when found – should be higher velocity, because they are most likely to be less elongated.

    SOMEWHERE along the velocity range, there must eventually be found a circular-to-elliptical transition. Rio Cuarto is certainly the low-velocity at the bottom of the range. At least for now. But how FAST might Rio Cuarto have impacted and still been elliptical?

  • jim coyle

    Steve; Here is one explanation of why craters are mostly round. (The explanation of this is that when an asteroid hits a planetary sized body, the initial crater (which may be elongated) is wiped out a few milliseconds later by the explosive release of kinetic energy. This explosion creates an essentially spherical impact feature.) This paragraph is from Dr Andrew Glickson’s article on the Mt Ashmore Impact Crater.

  • Steve, in the tests I did, even with a relatively slow veleocity impact, I could not get a nice, oval, crater at all.
    All of my shots, except for the very low angled ones, produced a fairly round depression at the point of impact. That thing that changed the most with changes in impact angle was the ejecta patterns. Where a butterfly pattern was the most common signature of a low angle shot. Instead of the oval crater one might intuitively expect.

  • jim coyle

    Gents; I’m not sure which thread to put this on so it goes here.http://www.msn.com/en-us/news/technology/earth-has-a-layer-no-one-knew-about/ar-AA9XbJd?ocid=iehp It’s interesting to say the least.

  • jim coyle

    here’s another interesting video. http://www.bing.com/search?q=video+pouring+lava+on+ice&form=PRNWSB&mkt=en-us&refig=e7c68706ab5d4640b1dcae34966cee06&pq=video+pouring+lava+on+ice&sc=0-17&sp=-1&qs=n&sk= I thought there would be a massive explosion but no! Now if you throw water or ice into lava—LOOK OUT!! Velly intellesting?

  • jim coyle
  • Steve Garcia

    Jim –

    On the lava-on-ice thing, cool – but I will try an off-the-cuff possibility to explain it:

    I am pretty sure the weight – AND VISCOSITY – of the lava is suppressing the ‘exploding water’ – but not completely. It is in all cases of resisting force-vs-expanding force. Notice the (mostly) large bubbles – evidently there is some of the water steaming up and expanding and with enough pressure to push up through the lava.

    SOME of the bubbles burst, but notice that that happens kind of in slow motion. Why? I think it could be because the higher the bubble rises the more the lava gets cooled by the steam (and abetted by the air right at the surface), so the lava is a bit more viscous on top, resisting even a bit MORE.

    When it is water on top, its weight is nothing close to being able to resist the expansion pressure/force, so it goes ‘nuclear’.

    This DOES perhaps have some application to a meteor impacting ice, so this is a good ‘get’ by you.