Independent confirmation: Young bucks at same school double-check National Academy member and YDB author Kennett’s nanodiamond claims — found ’em

012714-excavation-350

 The excavation at Bull Creek, Oklahoma, shows the paleosol — ancient buried soil; the dark black layer in the side of the cliff — that formed during the Younger Dryas. – UCSB

 

More recently, another group of earth scientists, including UCSB’s Alexander Simms and alumna Hanna Alexander, re-examined the distribution of nanodiamonds in Bull Creek’s sedimentological record to see if they could reproduce the original study’s evidence supporting the YDB hypothesis. Their findings appear in the Proceedings of the National Academy of Science.

 “We were able to replicate some of their results and we did find nanodiamonds right at the Younger Dryas Boundary,” said Simms, an associate professor in UCSB’s Department of Earth Science.

The paper

Arkansas 

UCSB Press Release

University of Oklahoma Press Release

Editor: Jay Melosh

What Killed the Woolly Mammoth? UCSB Professor Finds Evidence to Support Comet Collision

 

Alex Simms

Alexander R. Simms

Could a comet have been responsible for the extinction of North America’s megafauna — woolly mammoths, giant ground sloths and saber-tooth tigers? UC Santa Barbara’s James Kennett, professor emeritus in the Department of Earth Science, posited that such an extraterrestrial event occurred 12,900 years ago.

Originally published in 2007, Kennett’s controversial Younger Dryas Boundary (YDB) hypothesis suggests that a comet collision precipitated the Younger Dryas period of global cooling, which, in turn, contributed to the extinction of many animals and altered human adaptations. The nanodiamond is one type of material that could result from an extraterrestrial collision, and the presence of nanodiamonds along Bull Creek in the Oklahoma Panhandle lends credence to the YDB hypothesis.

More recently, another group of earth scientists, including UCSB’s Alexander Simms and alumna Hanna Alexander, re-examined the distribution of nanodiamonds in Bull Creek’s sedimentological record to see if they could reproduce the original study’s evidence supporting the YDB hypothesis. Their findings appear in the Proceedings of the National Academy of Science.

“We were able to replicate some of their results and we did find nanodiamonds right at the Younger Dryas Boundary,” said Simms, an associate professor in UCSB’s Department of Earth Science. “However, we also found a second spike of nanodiamonds more recently in the sedimentary record, sometime within the past 3,000 years.”

The researchers analyzed 49 sediment samples representing different time periods and environmental and climactic settings, and identified high levels of nanodiamonds immediately below and just above YDB deposits and in late-Holocene near-surface deposits.

The late Holocene began at the end of the Pleistocene 11,700 years ago and continues to the present. The researchers found that the presence of nanodiamonds is not caused by environmental setting, soil formation, cultural activities, other climate changes or the amount of time in which the landscape is stable.

The discovery of high concentrations of nanodiamonds from two distinct time periods suggests that whatever process produced the elevated concentrations of nanodiamonds at the onset of the Younger Dryas sediments may have also been active in recent millennia in Bull Creek.

“Nanodiamonds are found in high abundances at the YDB, giving some support to that theory,” Simms said. “However, we did find it at one other site, which may or may not be caused by a smaller but similar event nearby.”

A “recent” meteorite impact did occur near Bull Creek but scientists don’t know exactly when. The fact that the study’s second nanodiamond spike occurred sometime during the past 3,000 years suggests that the distribution of nanodiamonds is not unique to the Younger Dryas.

 

 

 

  • Steve Garcia

    agimarc – “This means that there will be an enormous amount of material in orbits that are outside the plane of the ecliptic and we just don’t see that much stuff.”

    That map argues against this statement.

    Yeah, I had always thought the asteroids were down close to the ecliptic, too.

    There is a LOT of stuff in high inclination orbits. And 99% of it centered at the orbit range of the asteroid belt.

    It just took somebody to MAP them.

  • Steve Garcia

    agimarc –

    No, Itokawa is not a rubble pile. It is a solid rock with rubble sitting on its surface. Big difference. Google Image it. It is two different things – mainly a big rock and minorly all the dust sitting lightly on it.

  • Steve Garcia

    agimarc –

    Also, the defense guys shouldn’t worry about piles of gravel. On entry the turbulence rips the gravel away into individual meteors which will burn up. Chelyabinsk showed us that even 50 meter objects pose little threat – that one ended up as a one-meter object falling into Lake Chebarkul.

    The atmosphere is a terrific defense shield – they can sit out in folding chairs and watch the brilliant and harmless fireworks display. Millions of shooting stars, all glowing into nothingness at the same time. They might even be able to read from the illumination…LOL

  • Steve Garcia

    agimarc –

    “Yet another piece of the puzzle is olivine. It has been observed at Chicxulub. Question is whether it is excavated by the impact or created by the impact. My guess would be the former, but I have seen nothing to disprove the latter, and would need to see a lot more papers to embrace the latter.”

    Look up how deep the melting occurs on meteors. It hardly goes deeper than a few millimeters. The bodies of meteorites show this clearly. The internals of Allende meteorite never experienced any great temperatures, and especially no great pressures. (The front face? Much different. Nice melting there – but STILL not enough to create olivine.)

    The olivine did not happen upon impact. Not enough impact to even break it. >4 million PSI on the front side would have vaporized it. Many fragments broke off in flight (from pressures far too low to make olivine), but the meteorite itself never vaporized, so the impact was much more like stuff falling at Chelyabinsk.

    I have looked high and low for an image of the crater, but so far nothing.

    “There is at least one disk I read of thought to be created by violent disruption of whatever formed earlier, meaning the process is not always additive.”

    EXACTLY. Look at any impact on asteroids or moons – show me ONE place where the impact AS SEEN is additive. All of them are subtractive. There is material removed. WHERE is one example of an impact actually adding anything? Dust on the surface doesn’t count. It’s got to be fused. The entire visual record is subtractive, but they tell us it was different in the past. Huh? That is the opposite of Uniformitarianism. And the relative (impact) velocities now should be more or less what they were back then, so how come NOW they take away, but in the beginning they added?

    I can’t figure it out, not from their starting point. Everywhere I look observations turn up dead ends, logically and experience-wise. Certain processes simply can NOT occur without great pressures and great temperatures. Those minerals simply cannot have been formed by the processes they put forward.

    Yeah, a lot of head scratching…LOL

    One of the tough problems is that in order to offer up alternatives one has to go into all of their theories and shoot them down, before one ever even gets to presenting the alternative. In the process, one loses one’s audience. Or get tied up in haggling over their theories. (And when you get even that far, they pull out the crowbars and argue all sorts of twisted logic to who how their thing could POSSIBLY have occurred.)

    The bigger the crowbar, the wronger the idea.

  • Interesting map. Would be interested in seeing how those objects are grouped in families of bodies with similar orbital characteristics. The Jupiter Trojans don’t prove a lot as they tend to wander around the L-points rather than traveling in well defined orbits. Perspective on things at or near the L-points is entirely based on your frame of reference (haven’t said that well either).

    Will continue to disagree on Itokawa. One of the giveaways to internal structure is lack of craters. It either means that the body has been resurfaced or has some depth of regolith. Regolith that goes all the way thru to the other side makes it is a rubble pile. If I remember correctly, the debris field / rubble pile explanation was first offered as an explanation of why there was so much area on Eros without craters (NEAR, 2000). The internal dynamics are interesting in that whatever insult you do to the body imparts a shock wave that bounces around for a long time, smoothing things on the surface.

    The planetary defense guys are looking at objects in the kilometer to larger size, at which reentry of rubble piles gets to be pretty exciting.

    It looks like Miranda was put together via an additive process. We didn’t see the process, but we do see the result. Some of the JPL speculation has it disrupted up to 5 times before reforming as we see it today.

    We see additive processes going on in the shepherd moons of the rings of Saturn. We also see it via the “propellers” and other bodies in the ring plane itself. Saturn’s rings may be a pretty good testbed on accretion dynamics.

    http://www.wired.com/wiredscience/2010/07/saturn-ring-snowballs/

    The old lawyer rule of thumb is to when the facts are on your side, pound the facts. If you don’t have the facts, then pound the law. If you have neither, then pound the table (crowbars and tire tools). Hope not to go there. Cheers –

    Cheers –

  • Steve Garcia

    Jim –

    Having read a bit on Liesagang rings, I don’t see an exact application, but it was something to look at. If I might have overlooked something really significant about them, holler at me to look again.

    Those effects happen at ambient room temps and ambient pressure.

    The needs of differentiation within asteroids and comets is ultra-high temps and ultra-high pressures.

    What asteroids and comets actually have always had (in a non-electric universe, – which alternate I do not want to get into at this time) is vacuum and ultra-cold.

    Those are three very different conditions.

  • Steve; As i was reading on the liesegang rings they mentioned the inclusion of quartz in the formation of some of this rock type. Wouldn’t you need extreme heat to liquify the silica to form Quartz. Another concept for the straification of the earths crust is like in the melting furnaces at work. As you are melting the aluminum the impurities seperate from the base metal and either come to the surface or fall to the bottom. I’m sure the earths furnace works prety much the same with different minerals and rock either rising or falling according to mass weight. As some materials combine they probably act as a flux to purify some of the molten materials. Also wouldn’t the spinning of the earth have a small centrifugal effect also causing the molten masterials to seperate according to mass weight. Unfortunatly I can also see this whole concept work as a mixing bowl for the earth’s molten soup. Maybe under Vacuum conditions you don’t need heat to form the ring like structures. Again at work we use vacuum vessels to aid in cooking off of liquids from some of our slurry products so we do not have to provide as much heat to the process.

  • Trent Telenko

    >>Also, the defense guys shouldn’t worry about piles of gravel. On
    >.entry the turbulence rips the gravel away into individual meteors
    >>which will burn up. Chelyabinsk showed us that even 50 meter objects
    >>pose little threat – that one ended up as a one-meter object falling
    >>into Lake Chebarkul

    Ummm…no Steve.

    A 10km rubble pile that got turned into atmospheric heat energy, without ground impact, is still conserving its total kinetic energy.

    That much heat dumped into our atmosphere simultaniously will show up as huge atmospheric blast overpressure and radiant heat scorching of the planet surface.

    Think of a 20 minutes visit inside a 500 degree F oven for an entire hemisphere.

  • Steve Garcia

    Jim –

    I don’t everything about this general subject, but I know enough to get myself in trouble…

    All of the rising and sinking you discuss there is in liquid state. So, that is one of my points – where does the heat come from to liquify? Some people suggest impacts. I can’t see that working, because all the impact evidence we see on asteroids and comets are subtractive – you lose way more material than you add. Plus something like 99% of the heat energy goes out in the ejecta. At no point in an impact does the entire body or large part become molten. Whatever goes molten DURING the impact has to deal with the immense forces tearing the crater apart.

    Differentiation needs a non-chaotic environment – a contained and sustained pressure and temperature both. That isn’t to say that heat and pressure in a snort-lived event doesn’t change things. Of course it does. But it isn’t going to result in layers laid down nicely. I would say that that is partly why impactites are recognizable as such, because of the evidence of chaotic formation. Nanodiamonds can be made via detonation or by sustained heat and pressure – and the results are different types of nanodiamonds, some ten or twenty times larger than others.

    As to the vacuum used, as I know it, vacuum causes boiling off at very much lower temperatures. It can also be used when no atmosphere is suitable, but then they have to deal with the low vaporization temp. There is more to it than that, but those are conditions to consider.

  • Steve Garcia

    Trent –

    Still just head scratching, and not arguing…

    A 10 km pile coming in as one body will wipe out humans forever – very possibly. That would ostensibly make a crater 200 km across – not far short of Chixculub.

    No matter HOW much heat 1,000 50-meter objects cause, or how many air blasts like Chelyabinsk, the human race will continue. We have about 336 cities at present with 1,000,000 people or more (791M people). The odds of all of those plus another 256 with 600,000 to 1,000,000 (192M). Then we have another 321 with 400,000 to 600,000 (159MM). And let’s add in the 340 with 300,000 to 400,000 (117M).

    That is 1253 cities with 1.26 billion people. More or less. There are 5.8 billion OTHER people on the planet.

    Even if every one of those cities got a Chelyabinsk at the same time (not gonna happen), no major damage. If each of 25% of those cities got 4 of those Chelyabinsk meteors, each is going to have four times as many broken windows. Even four of them are not going to add more than a blip to the heat content of the local environs of each city.

    NO ONE has stated ANY problems with heat in Chelyabinsk or any of the neighboring cities and towns.

    It is not correct to say that the incomings are going to conserve their heat energy. First of all, they don’t intrinsically HAVE any heat energy. The heat is the air ahead of them being compressed and then ablating the front side.

    Secondly, Chelyabinsk LOST 90% of its energy along its path inside the atmosphere. It hardly “conserved” any energy at all. By the time it “blew up” (disintegrated) there wasn’t a lot left to disintegrate. A 50 meter object was reduced down to about one meter across. The rest melted off for about 25 seconds or so, and the rest was fragmented.

    Other than glass cuts and some blown in doors, Chelyabinsk didn’t have any casualties.

    If that is the best a 50 meter object can do, we need to rethink our strategies and our concern.

    Now if Chelyabinsk had been 100 meters, it possibly would have reached the ground. As it was, it blew up at about 23 km up. It had a LONG way to go to the ground. The very thin upper atmosphere had used up its kinetic energy. The much thicker lower atmosphere would have done a lot toward airblasting it into nothingness.

    ABLATION is a BIG and very important process when these things come in.

    And more and more I am convincing myseelf that nearly all incoming bodies are low angle entries – like Chelyabinsk and Tunguska and all the other bolides we see videos of. VERY FEW of them have enough oomph to make it to the ground.

    WHY do I think they are almost all low angle? One reason is videos. Not many videos are of ground impacts. We almost always see objects going almost straight across the sky. I think I know why:

    The Earth’s gravity well is ~1.8 million miles in diameter. Anything entering any part of that cross section is STUCK and WILL spiral inward – unless it is going faster than 11.2 km/sec. Most objects out there are going 2 or 3 times that fast, so the effective gravity well for those is much smaller. But I don’t have numbers on it. My guess is about 10 times the diameter of Earth, but let’s set it to four times, to be conservative. We DID have that other fly-by the day after Chelyabinsk – plus other close encounters. Things happening to be traveling in the same direction (as most of the NEOs are) the RELATIVE velocity is much smaller. Because Chelyabinsk WAS one of those it did a good bit of wrap around as it spiraled in, and was only going 19 km/sec as it entered the atmosphere.

    Assuming that 4X figure isn’t bat sh** crazy, the effective gravity well for incoming objects is 4^2 larger than the Earth’s physical target area. That would be 16 times the area, with the Earth being one of them. But let’s even cut that down by four times. The gravity well target area then would still be four times bigger than the Earth, meaning that 75% of the objects coming in will MISS the Earth if they don’t get deflected. Those 75% will spiral around the planet to some degree and enter the atmosphere at some fairly low angle. Chelyabinsk was a 20° downward angle. Tunguska was estimated to have a 15° downward angle. Are those typical or not? Scientist often say that the average one comes in at 45°. I think they are likely to be wrong on that. I think it is more like 20°-30°.

    The longer they are in the atmosphere, the more spread out their energy signature will be along their trail. And all along that trail, they are giving up massive amounts of energy, spread over thousands of miles. Chelyabinsk’s path in the atmosphere was at least 4800 km long. 500 kilotons spread over about 5000 km times 90% equals about .09 kilotons per km – and 40 km up in the sky.

    If 3 out of every 4 come in like that – spiraling in at low angle – we have no problem, if they are rubble piles that break up as they approach or as soon as they hit the atmosphere.

    A lot off little objects do NOT add up to the same effect as one big one.

    Tunguska was 100 meters. THAT poses problems. Chelyabinsk was 50 meters. That was NOT problematic, just a good thrill. Cool fireworks.

    So, we have a range, a threshold. Unless it comes straight down, steep angle, punching through the atmosphere quickly, somewhere at around 60-70 meters the danger becomes non-city threatening. Maybe even 80 meters. That might be useful info to know some day.

    For the above reasons, if they are valid – and PLEASE argue the other side (if they aren’t I’d like to be rid of them) – I favor comet busting nukes as a mitigation strategy. (And I have some preferred strategies for doing that, too.) The main argument against it is: “But then you’ve got thousands of incomings!” But if they are 50 meters or less, we have no worries, as a species, and probably even if they are focused on one region. It doesn’t matter how many little ones there are. We will survive.

    It is the big suckahs we gotta not have a date with.

    Yeah, the big ones are gonna do us in. So we need to not let big ones hit us.

    Trent, throw some stuff back at me. Show me that Chelyabinsk was harmful to anything but windows and people unfortunate enough to be standing near them at the wrong moment. If every city had a meteor like that come by, what real harm is done? If a city has ten of them at once, then what? Besides lots of broken windows and garage doors, is it really a serious threat?

    Tunguska? Even Tunguska over a city I think is not city threatening. Dead? Yes. Perhaps thousands. But it won’t take the city back to the stone age.

    Would I want to be standing under it? Probably not…LOL But standing under a 50-meter jobby, yes. It would be cool. 5 of them? Sure! Five times as cool.

  • Steve Garcia

    Oops. Chelyabinsk was not 50 meters, but 50 feet, or about 17-20 meters. Sorry about that…

  • Steve; I think your priority is off. Yes size does matter but timing is everything. If you don’t have enough lead time to set up an intercept launch You have a whole of S.O.L.! Another thought : As a species if the proper two are left the rest will come. Does the government have a list of possible–probable impactors? If so maybe they should start sending up expendable out of date nukes for target practice. We can even let the Russkies take few pot shots to downsize they’re arsenal that they, like us, don’t have. It would be good for the business I’m in, Aluminum Powder- rocket fuel. We can always make more powder.

  • Steve Garcia

    Jim –

    The database of NEOs includes those which pass close to Earth in the next 10 or 30 years, and so far none of those have them worried. SO, none to practice on, and for the most part they are out of range most of the time, anyway.

    Flowing one of the links above, some page said that on Monday a 27 km asteroid is coming within 2,000,000 miles. That one supposedly they almost missed it, until the last few days. Not sure how one can miss a body 27 km, so I am not convinced the web site even knew what they were talking about. That is nine times bigger than Encke.

    I am pretty sure that when it comes time to shoot at anything it will most likely be the Russians or Chinese who do it. My reasons for thinking that: As each year goes by the Chinese are catching up. The Russians have a less b.s. government plan, plus they are the ones who had Chelyabinsk last year, and they were going to ramp up their protection program because of that. NASA is underfunded and has to play a lot of suck up just to get a bone. And mostly they get boned because of that. They have too many possible projects and way too little money, so most programs get pushed aside.

  • Steve Garcia

    Darn! I was going to write that that object was 270 km across, but thought my memory was faulty, so I changed it to 27 km. But that was NOT what the article said. It said 270 km after all. (I should have checked!)

    But 270 km would be one of the 10 largest minor bodies in the solar system and would certainly have been seen long ago.

    Even more reason to doubt the veracity of the article…

  • E.P. Grondine

    Hi Steve –

    “I don’t everything about this general subject, but I know enough to get myself in trouble…”

    Yes, and I need to apologize to you for my lack of time.

  • Trent Telenko

    Steve,

    A 20 meter diameter object has a 10 meter radius.

    A 10 kilometer diameter object has a radius of 5,000 meters.

    5,000/10 = 500 times larger value of “r” for radius.

    Assuming a uniform spherical volume for both objects allows the use of this formula:

    Sphere Volume = 4/3 pie r^3

    A 10 km object has 4/3 Pie (5,000)^3 internal area compared to 4/3 pie (10)^3

    Assuming a uniform and identical density of mass between two spherical objects, the 10km object has on the order of 125,000,000 times the mass of a 10 meter object, assuming a uniform and identical mass density between the two objects.

    0.5 megatons for a 10 meter object energy yield times a 125,000,000 larger mass, assuming a uniform and identical to heat conversion, comes out to 62,500,000,000 megatons.

  • volume goes with the cube (raised to the third power) of radius. The same is true if you speak of diameter instead of radius, just a different coefficient.

    NASA takes major step in hunt for asteroids
    http://www.spacedaily.com/reports/NASA_takes_major_step_in_hunt_for_asteroids_999.html

    when you get to 1000 (one thousand) megatons that is a Gigaton. Continuing up the ladder of escalating energy, one thousand (1000) Gigatons is one Teraton of TNT equivalent energy or “yield” as they so politely call it in the nuclear weapons industry. The Chicxulub impact is believed to be on the order of 100 Teratons TNT equivalent.

    And although some impact specialists will have you believe that this or that value of “yield” is continental disruption vs global disruption vs extinction at this or that level, they actually don’t know. They have no valid data points because EVERY IMPACT IS DIFFERENT AND UNIQUE.

    So even the frightening energy level of Chicxulub’s 100 Teraton shot isn’t an exact guideline, or even a rough guide, because that same energy in a highly oblique shot to a thick ice sheet is a completely different story. It is truly mind bending to learn about the diversity of effects and variables coming into play in hypersonic impacts.

    If Tunguska was caused by a 70 meter object (estimate) and a 250 meter object just missed Earth last week, then that recent miss was ~3+ orders of magnitude more volume than the Tunguska object. So things get ugly fast as the size increases, given all other variables the same (speed, density, friability). But no two objects are the same either, just to keep us guessing.

    And all the modeling in the world using every computer on the planet still won’t divert a single cosmic projectile from impacting Earth if it is already on such a course. And even the best numeric simulation on the best computer won’t capture all of the detail of the shock from an irregular bolide on an irregular surface. Those computer simulations all have to start with a set of assumptions which are most likely not representative of 99.9% of all objects out there, because no two are the same.

    Continuing on this rant of overflowing optimism:

    Kinetic energy also goes up with the square of velocity, or the second power of velocity (V^2), so the faster the object, the more damage it can do. Coincidently, the faster the object, the less time between discovery and close approach if it is near Earth or Earth crossing. Although that is not always the case for huge and/or bright objects, its the sub kilometer-coal dust covered objects we need to look for with the most diligence. Especially the fast ones, which may often be from the furthest out in the solar system and correspondingly hard to detect and track.

    The reason the governments will finally step up to more resources for the search is one of money. The economic disruption of a land impact or the more likely impact tsunami is a serious factor to consider. Who is at risk the most? Countries with the most population near the coast, yes. But unfortunately, the countries with more infrastructure are the ones who stand to suffer the most economically from significant cosmic impacts.

    Poor nations with no infrastructure will still go on like they were before an impact. I’m not being snide or righteous, but that’s just the way it is. Why doesn’t the UN do anything about ethnic conflict in Africa? Think about it. There is no economic interest to protect in that case. Sad but true.

    So if you talk to politicians, always try to impress upon them the economic risk of cosmic impact. Nations like the USA and other well developed infrastructure users stand to lose the most from an economic standpoint. So –

    We should simply think of cosmic threat protection investment as the cost of doing business on our planet, simply because of the “wrong element” in our ‘local neighborhood’. Its like the money for the alarm on the shop at night. Especially because of the small and speedy faction of that “wrong element”.

    Worse than kids on skateboards, heaven forbid!

    TH

  • Steve Garcia

    Trent –

    Not to be obtuse, but it seems you are arguing my point for me: If larger is a LOT more dangerous, then smaller is not just a LITTLE less dangerous, but a LOT less dangerous.

  • Steve Garcia

    Tim –

    “Coincidently, the faster the object, the less time between discovery and close approach if it is near Earth or Earth crossing.”

    The direction of approach is important, too. A head-on collision is not as bad as a rear-end. And a rear-end should take longer to close the gap, yes? Basic physics, yes?

    Also, yes, infrastructure is what civilization is all about. Infrastructure is there to facilitate commerce. At ALL levels of civilization. There IS no civilization without infrastructure. That is THE advantage of our modern society – to each and every individual – from schools to streets to water to sewers to courts to hospitals to lines painted on streets to shops to goods distribution methods, etc. Take it all away and watch us look for caves or trees to live in. And then take ten thousand years to come back.

    (Digression…) But that is why arkies looking at graves, stone structures, and carvings on stone structures (especially monuments) miss the point – because of at least these things:

    1. Graves have nothing to do with infrastructure.

    2. Carvings and monuments don’t feed people or make their lives easier/better/more functional. The infrastructure of old societies is only minimally tied up in stone structures.

    3. Most of infrastructure is in laws and contracts (controlling behavior for the common welfare), and making and selling things; if taken down, a society will use up its “thing making” capabilities first, in trying to recover. Thus, those are the things least likely to survive long afterward. They will scavenge until there is nothing left to scavenge. So, (unless protected like at Pompeii or Akrotiri) what the society is about disappears quickly and is not available centuries or millennia later for arkies to find. Assuming that they can even minimally feed themselves, the most important persons in a reduced-but-surviving society after a hit are the engineer types and inventor types (including ingenious farmer types), the people capable of looking around and figuring out how to utilize what is left.

    Yes, I’ve put some thought into this, and everyone is entitled to disagree with me.

    A GOOD part of the preparations/mitigations should be putting some thought into how to rebuild. Mitigation, after all means to limit the negative effects. They may not end at trying to knock the incoming object into some condition less impactful.

    Pun intended.

    And, yes, like any other angle, getting politicians to understand the money side of it is likely the best way to go. Look at the reaction of Russia after Chelyabinsk last year. They saw how it could undo all that they are working toward (a richer, more western lifestyle). And money is at the root of all of that. I believe China also was rousted up about it; after all the meteor passed almost all the way across China just before exploding. A second or two here or there and it could have been Beijing or one of China’s other one hundred plus >1,000,000 cities instead of Chelyabinsk.

  • Jo Nova has an article on the quick entry into the YD. More interesting is that there is a graph that shows coming out of the last ice age and heating up after the YD was equally as fast. So like what makes things heat up so quickly? We think we know what cools things down. What about the other direction? Cheers –

    http://joannenova.com.au/2014/02/greenland-ice-cores-show-natural-swings-are-large-and-warming-means-less-storms/

  • Steve; Thanks for the shout out to the farmers. We are capable of fixing just about anything. It may not last long but it will get the job done. Bale twine and duct tape can conquere all. I saw a program last night, How The Universe Works, about the formation of planets. Their premise for formation is that when a star is born there is an immense amount of cosmic debris left over that circles the star. As this debris goes around microscopic particles bump into each other some stick some don’t, random choice. Each particle is charged so that is the attractant but the force of the bump determines whether or not they stick. This keeps going on until there is enough mass to actually attract larger pieces,and from there accreation takes over. At approx 500 mi dia the object can form it’s own gravity then the spinning process starts and the evening out of the sphere starts happening. the spinning is supposed to make the shpere start condensing until it is hot enough to melt the debris it has accumulated and then the crashing of other planets occurs some get eaten and some are physically destroyed until the field is cleared and there is nothing else left to crash and burn. This scenario only applies to rocky planets the gas giants are a whole another matter for another show. According to the show all matter in the universe is the same but how it comes in the form of planets is a crap shoot. Another item discussed was the formation of this planets magnetic field. The reason we have an atmosphere is trhe solid iron core of the planet. Some people in the scientific communtiy built a mock up of the earths core and surrounded it in a liquid sodium (Magma)then spun it and sure enough it created magnetic field. Spinning just the sodium or the iron ball produced nothing. Interesting. I’m sure you can shoot holes in the theories, I did, and ask the eternal question: But how did it all start?

  • Steve Garcia

    Jim –

    That account is mostly very reasonable and most of it is likely true. For planets.

    The 500 mile diameter thing doesn’t account for much smaller objects, though, does it? If they are too small to create the melting (which I am sure happens deep), then I hope you understand that that is exactly what all my questions are about. How does a 20 meter body have rock or metal that has melted and then cooled into a solid? And how does the matrix in meteors get mall fused together, with inadequate pressure and temperatures? The answer is NOT “lot of time.” If anyone answers with “time” then they are cheating with a vague process they don’t even know anything about – and with that answer they are admitting that they don’t know.

    But if a 20 meter body could not generate sufficient gravitational force to melt rock, then we have to explain its existence. That melting diameter is the dividing line: Smaller ones can’t melt themselves, and larger ones MUST.

  • Steve Garcia

    Jim –

    The peridotite and olivine in the Allende meteorite HAD to form at high temps and high pressures – much higher than to merely melt. The question I’ve been asking is:

    “How do they account for melting and fusing in an object that entered the atmosphere at only the size of a car?”

  • Steve; I think the question should be where did the melting occur. The program stated that in the formation of this solar system at on time there were well over 100 smaller planets (don’t how they counted them )all careening around within the gravity of the sun. At this time in creation most were rocky molten masses.As some crashed into others they either were assimilated or the impact caused one or the other to disintigrate and instanatly cool forming the asteroids we see today by splattering into the vacuum and cold of space. I have a piece of aluminum that formed in the uptake stack of our melting furnace. It looks like a small hornets nest or a large tear drop. The operator of the furnace had a bad nozzle that was spattering and blowing gobs up the stack instead of particles. The gobs stuck together and formed the nest. I’ve also seen dross from furnace fluxing that looks alot like meteors. comes out hot and cools real fast before taking any particlular shape.

  • Trent Telenko

    FYI —

    Meteorite Impact On Moon Sets Record As Brightest Ever Seen
    by Bill Chappell
    February 24, 2014

    http://www.npr.org/blogs/thetwo-way/2014/02/24/282201355/meteorite-impact-on-moon-sets-record-as-brightest-ever-seen

  • Steve Garcia

    Jim –

    Yes, where they formed is very pertinent, too.

    “At this time in creation most were rocky molten masses.” Where did the heat come from to melt them? And like I keep saying, SOME of the materials in them need ultra-high pressure as well. Collisions cannot be called upon for performing this miracle, because collisions IN THE PRESENT do not fuse objects out there – collisions rip them apart (look at craters; they are negative, not positive gains) – exactly the wrong thing to happen. To invoke collisions in the past is to negate Uniformitarianism, which says that the guide to what happened in the past is to look at what happens in the present. If collisions NOW break things up, then that would be also what was possible in the past. But they say it did the opposite. It does not compute. (HINT: The collisions was speculative when presented, but one that became accepted as fact.)

    What most people don’t know is that papers are still being written, with the authors floundering for an answer.

    As to your furnace being an analog for this, now take away the heat of the furnace and the gravity of the Earth. Now tell me either one existed back in the nebula. And it isn’t just the gravity of the Earth – you need to go hundreds of miles INSIDE the Earth to get sufficient pressure. It is the weight of hundreds of miles of rock above that creates the pressure. 100 miles inside the Earth is as far from being nebular as you can get.

  • Cevin Q

    Steve,
    The heat to form these minerals came from the planetary nebula and ultimately from the death of the star that formed said nebula.
    The free atomic gasses that make up the nebula react to form the basic minerals, which then start to coalesce while the nebula is still very very hot, think physical vapor deposition as a manufacturing process. The hot gasses of the nebula will start to condense on a cooler solid surface.
    The larger chunks we see today come from the destruction of early planetesimals as they collided with each other during the very chaotic early eras of a solar system. The iron/nickle objects are most likely leftovers from the formation of the moon, the remnants of the core of the planet that collided with the young earth.

  • E.P. Grondine

    Hi Steve –

    “Yes, I’ve put some thought into this, and everyone is entitled to disagree with me.”

    So have I, for over 17 years now.

    “A GOOD part of the preparations/mitigations should be putting some thought into how to rebuild. Mitigation, after all means to limit the negative effects. They may not end at trying to knock the incoming object into some condition less impactful.”

    NO.
    We can stop them if we can find them early enough.
    The US plan for doing it was sent to the UN recently.
    Russia, Europe, and China will be sending in their plans soon.

    Aside from that, much better detection systems are needed for immediate warnings of smaller impacts.

    Feel free to disagree, but those are all facts.

  • Steve Garcia

    Ed –

    Link to the U.S. submission?

    You and I both know that if a 3km jobby shows up at any time in the next 30 years (perhaps 100 years), we have no defense. Finding them early enough is fine, but we have huge ones going by almost not seen till they pass. So, yes, we MIGHT have sufficient warning, and we might not. Ergo, it is prudent to not put all our eggs in one of the rocket solutions and pretend that that is all we need to do.

  • Steve Garcia

    CevinQ –

    “The heat to form these minerals came from the planetary nebula and ultimately from the death of the star that formed said nebula.”

    1. What evidence do we have that the planetary nebula was 3,000C? If so, where did all that heat go?

    2. And this doesn’t address pressure, which is ALSO necessary. It is significant that the Allende meteor paper I have referred to as actually studying the processes within the deep mantle of Earth, and that the authors specifically asked if somehow the meteorite had orginated inside a planet. That was option $1.

    3. The star that formed the nebula? Would this star have any name or evidence of ever having existed? If it went nova, why didn’t the material vamoose out of the solar system?

    This entire concept is one I’ve never heard a peep about. Please enlighten me; I am eager to learn about it…

  • Steve; From what I had gathered the Earth or other rocky planetoids were not able to generate any heat until they hit the Magical Number of 500 mi dia. At that point they are supposed to be able to generate gravity which starts the condensing process which in turn starts the heating process as Gravity pulls more space debris into the forming planet the gravity gets stronger the heat gets more intense and the cycle continues until there is not enough material readily available to to keep up the building process then cooling starts. Collisions between mini-planets caused some to be assimilated and some to be destroyed. I would imagine that vast amount of the debris formed also fell in to the sun and was consumed.As the planets cooling continues the crust forms and as it gets cooler and cooler the crust starts to shrink squeezing the mantle and core keeping the heating going. Eventually the molten part of the planet will solidify and the planet will die. Our magnetic field will disappear and the sun’s cosmic rays will toast us and earth will look like Mars. This is most likely not in my lifetime. Sorry for the disjointed presentation.

  • Steve; Another idea, kinda on the far side but; What was here before the Big Bang? Maybe all this cosmic debris is what’s left from the big one. All the universe is the original material and it just recombines as it travels outward. Now somewhere in the future if everything goes as planned and figured the universe will start collapsing. That’s going to be one hell of a show when all this matter comes flying back together. With that thought I will have another cup of bean juice and bid you aduieu

  • Steve Garcia

    Jim –

    On the Big Bang, you are talking with someone who agrees with astronomer Halton Arp who has argued since the 1960s that the Red Shift is not a Doppler effect and has been writing about it ever since. He lost several positions because he didn’t sign onto the expanding universe. And he had good reason. And without a connection between Doppler and the Red Shift, there IS no Big Bang. Thomas Gold and Fred Hoyle had the Steady State Theory, which has been all but abandoned, but I still see it as the best theory. I even have 3 or 4 proofs that the Big Bang didn’t happen. You can’t believe the size of the crowbar they use to fit stuff into the Bug Bang and expanding universe ideas.

    Quasars are Earth-sized objects (Maximum). The energy that reaches Earth signifies that they are either close or are very, VERY, VERY powerful. They hd to decide which. Their red shifts in the 1960s suggested VERY far away. But that freaked people out, because they seemed to be Earth-sized. How could something Earth-Sized be putting out that much energy – apparently the energy of an entire galaxy. The ONLY factor that said they were very far away was the red shift. But that is the factor they chose to go with. Arp has all kinds of evidence that they are NOT that far away – which solves the energy conundrum. I remember this clearly from the 1960s.

    They made the wrong choice. And went with the Doppler Red Shift, and shortly thereafter the Big Bang Theory was declared the winner over the Steady State Theory. Astronomy and cosmology have been on the wrong track ever since.

    Like Rupert Sheldrake says, “Science says ‘Give us one good miracle and we will figure out the rest. The miracle was the Big Bang, in which all matter in the universe was created from nothing, in one instant.”

    One disproof is that every once in a while they declare that they have found the farthest away galaxy, because its red shift says it is going at ninety-something percent of the speed of light and that it is therefore only several hundred million years after the Big Bang. The mistake? If one of them is that close to the Big Bang in TIME, then it also must be close to the Big Bang in DISTANCE, too. After all, if there is a big freaking explosion, it had to happen SOMEWHERE specific. But the geometry comes out impossible, and ALL the recent finds should be in the same small area of space. But they aren’t. Some are completely in different directions. They cannot ALL be close to the Big Bang in time if they are off in all sorts of directions. (I don’t expect anyone to follow that, BTW…) They play games telling us, “Well, NO, it isn’t matter that is flying out; it is space that is expanding.” That is B.S. There IS no space that can expand. Space is an empty vacuum. There is nothing to expand. They pretend like it is something mathematical, and that is horse crap. Math can’t represent nothing. Distance? Yeah, but it is distance through vacuum. THAT exists – but distance is NOT space. Distance is just numbers that they use to represent locations. They’ve turned nothing into something via the belief that what is in equations is necessarily real. Please, go out and pick up a meter. There is no such object. Not a meter of something – a meter itself. So, no, space cannot expand. And if it DID, we wouldn’t even be able to tell that it did, because our measuring sticks would also grow the same amount, proportionately. Ergo if the space were really expanding then the Red Shift would not even be detectable. The atoms (99.999999999999% empty space) would be expanding, too. It could be expanding and shirking right now and we would not be able to detect it. The fact that we DO see a red shift is therefore proof that it is not an expanding universe – and without the expansion, the Big Bang is impossible – an explosion that didn’t rapidly expand. Actually, that last is one more disproof. Even their expanding space doesn’t hold water – it is internally contradictory. It is all absurdities.

    And what has cosmology and astronomy given us ever since then? More and more absurd paradigms. Dark matter, dark energy, string theory (which has never and WILL never have ONE empirical experiment that can prove it is not false).

    It’s all just Jabberwocky:

    Twas brillig, and the slithy toves
    Did gyre and gimble in the wabe;
    All mimsy were the borogoves,
    And the mome raths outgrabe.

    Lewis Carroll, the author, was a mathematician – which is PERFECT. He saw over 100 years ago how math can confabulate and give results that are sheer nonsense. Like Big Bangs, expanding universes that can be detected, and quasars the size of Earth putting out the energy of entire galaxies. (I won’t even go into black holes…)

    Like the borogoves, I am all mimsy… LOL

  • Steve; I believe you’re on to something there. Jabberwocky IS the language of science. Wordage wordage wordage when all is said and done was anything ever said?You told me a while back that you enjoy playing the devils advocate–You’re good at it. I throw out ideas and you punch them out and hand them back to me. You make me think like I’ve never thought before. I’m still chasing the Drake passage idea and gaining some headway. I’ve got to get some time to sit down and collect all the data I’ve accumulated all over the web and organize it. Then I’ll bring it to the Tusk for a thorough ripping,shredding and general clubbing and start again. Hopefully if I can make an intelligent enough presentation and get some confirmation that this is the case then the concept of an ice sheet impact causing YDB might not be so hard for others to swallow

  • Steve Garcia

    Yeah, Jim – don’t give up on the Drake Passage conjecture. You are onto something there. All those arcs (and in some cases actual circles) in that pattern could easily mean something. It is VERY significant that not enough Earth craters have been identified; a great part of that is the conservatism of geology – they don’t even WANT to find any, so they do much more than play devil’s advocate: They are obstructionists (deniers, if one wants to think that, though I loathe that phrase; it is rife with suggestions of Holocaust deniers). They simply do everything in their powers to pretend that zero catastrophes have ever occurred except millions of years ago.

    Comparing the Drake Passage to Chicxulub is a no-brainer on the surface (no pun intended), as a likely impact event. 70%+/- of all impacts should have been oceanic, so SOMEWHERE out there – down there – are impact craters. Why not start looking? And if looking, why not look at anyplace that has arcs and circles? SOME of them will eventually prove out to be impacts, so why not begin the process of searching for them?

    One aspect of the Drake Passage’s characteristics is its location, there right where three plates intersect. To me it is an awfully big coincidence. Especially as the southern edge is the edge of the Antarctic plate. It begs the question: Did the fault line exist before or did the impacts have something to do with creating the fault line?

    That may sound like heresy. The tectonic plates are treated as if they have always existed. The heresy is to ask if they may NOT have existed forever. If they are floating islands (an almost silly idea, if you ask me) as Wegener envisioned and the geologists think at present, is it so sacrosanct an idea that the idea should NEVER be questioned at all? In engineering, NOTHING is unbreakable. You can always apply sufficient force or impulse to an object in order to break or cut or bend it – at least in theory – and no other engineer would bat an eye. There is no such thing in engineering as an immovable or unbreakable object. Why should the Earth’s crust – whether tectonic plates or not – be such magical un-crackable things? After all, the Atlantic plate has the Mid-Atlantic Ridge, and the Pacific has its East Pacific Rise – so obviously magmatic force can dent/penetrate the plates. And from what we have all learned, the greatest force that has ever been applied to the Earth’s crust is impacts. Why should we not even consider that an impact might crack the crust?

    Not all heresies are correct. But then, some of them have been shown to be, though the conservatives in scientific thought resisted them with all their might. We live in a present in which science says it only looks at evidence (and only objectively), but with the Daulton Gang and the Bos we’ve seen how silly the objections and the willing blindness can be. So, rather than cater to winning them over, we should simply go where our intellects and evidence tell us “There be dragons!” and let the chips fall where they may.

    Jim (and everyone else), if you haven’t yet ever done so, do a Google Image search for the Drake Passage. The assortments of images will amaze you. There has been a LOT of scientific work done in that area. Ignore the interpretations but let your eyes inform your effort.

  • Steve; Thanks for the encouragement. Either Trent or CevinQ gave a claculator for sizing theoretical craters. I used it in reverse to come up with a possible impactor size, speed and angle. Size 75-100km, Speed approx 75000 mph and angle 35-45 degrees. This accounts for the main crater and trench. The others are up to 66% smaller but probably same speed and angle. I had figured that the main impact had displaced approx 67 million cubic ft of earth either into atmosphere, space or shoved it across the ocean floor. Tim Cullen from the Malaga Bay site has commented on this idea and has suggested that the kinetic energy from the impact may still be going on causing all the vucanism in that area, He even posted a image showing all the earthquake and volcano activity in the Passage. It was very impressive. I’ve gotten a lot of help and info from the Malaga Bay site but I have to figure how to bring it over here and as I’ve said before organize it.

  • Steve: Brain f–t alert!!! In previous post I mentioned 67million cubic ft of earth, That was supposed to be 67 million cubic miles of earth. Minor technical error.

  • Trent Telenko

    Jim,

    It was CevinQ’s calculator.

    All I did was a straight forward scaling from Chelyabinsk to a 10 km body with the working assumptions assumptions of
    1. Spherical shape,
    2. Identical trajectory,
    3. Identical material density and,
    4. Identical energy release profile,
    to get a “ball park,” to a half an order of magnitude, plus or minus, energy release number.

    Needless to say, those are some _seriously flawed_ real world assumptions for any other impact.

  • February 2, 2014 at 21:13
    It looks like the Scotia Plate is the trench with the East Scotia Ridge marking its eastern boundary while also being the western boundary of the volcanically active Sandwich Plate which is “moving rapidly eastward, at rates from 65 to 90 mm/yr” with the South Sandwich Trench at the leading edge… so arguably the kinetic energy of the very low angled impact is still be dissipated.

    Take a look at the full USGS poster [at the link below]… you might see it differently….

    USGS poster of the South Sandwich Islands, Scotia Sea, Earthquake of 20 August 2006 – Magnitude 7.0
    Steve if you go to the above link you will see the poster they’re talking about

  • Steve Garcia

    Jim –

    Link? What link?

  • steve; Apparently the link didn’t come with the article. This transferring from site to site is puzzling for me. My problem. I would imagine you can go to USGS and lookup Sandwich Islands Scotia Sea Earthquake of 20 August 2006 Magnitude 7.0 that might do the trick or go to Malaga Bay and lookup Drake Passage Impact event. Scroll down some and youi should come across it. If not I will try to import the poster again. Sorry

  • Barry Weathersby
  • Steve Garcia

    Barry –

    Sometimes our minds work in funny ways…

    I don’t mean to take this off topic in any way, but something funny just occurred to me about the Main Belt object P/2103 R3. Two teams found it on the same day, which, of course, always brings up the question of how they can tell an object is a new object.

    THAT made me think of air traffic control computers, which keep tags on planes as they move around the radar screens. (An even further diversion would be to ask when are they going to make those 3D…)

    You can probably see this coming:

    Other than putting their minds to it, it seems like only a matter of time before they tag minor bodies and those tags then stay with the object forever. Impossible? Probably not. Difficult? I think yes, because we lose line of sight of the bodies all the time, with the Sun and daylight, etc. But the system can be a worldwide system with a main server dealing with them. Plus, once the orbits are known, the tags can follow the expected orbits and tell us if the orbits have changed. Yes, there are many, MANY thousands of them to track – but that is what big honking computers can do for you.

    I saw the other day that Rolls Royce is floating the idea of un-manned container ships, with 100,000 ships out there at any given time. That would use GPS, of course, but between something like that and air traffic control systems, one would think it is entirely possible. And perhaps a really nice plumb in someone’s hat (NASA? Are you listening?) to go get the companies that make air traffic control systems and see what it all entails.

    Hahahaha – remember when it happens that you heard it here first.

    Back in the early 1990s I had the idea of what is essentially an early version of car GPS systems. That was using microfilm type cards for maps and accelerometers to note changes in motion and time. Clumsy compared with what came, but five years later a Japanese firm popped up with a slightly higher tech version and I wished I’d gone and patented it and gotten in on the ground floor of that. The GPS versions only became possible because someone pushed and was able to convince the U.S. military that it ws not a security thing and to free up a lesser version of the GPS systems they had developed. That was the big tipping point. I would have enjoyed being part of that.

    This tagged asteroid system could very much simplify NEO detection by allowing them to automatically ignore known ones. Then when they spot a body moving across the background star map, it would be a new one. (Allowing for orbit changes due mostly to, but not limited to, Jupiter.)

    If a system like this currently exists, sorry to waste this comment!…LOL

  • Steve Garcia

    I will take a stab at what might have happened to P/2013 R3, just as an exercise in thinking about such things. Total speculation, based on the article.

    From the last paragraph, it sounds like it might have been a strengthless body. No collision was apparent, and its orbit didn’t pass near enough to a planet to tidally dismember it. (Strengthless bodies are the most susceptible to this, one would certainly think.) Since it’s fragmentation seems to have gone slowly, and it had a cloud around it.

    Objects in space have previously been observed to break up for a variety of reasons; they can be torn apart by a close encounter with a larger object such as a planet or the Sun, directly smashed in a collision with another object, be torn apart by the pressure of internal gasses sublimating (turning directly from solids to gasses) as they warm, or be torn apart by rotational stresses.

    The only two of those which seem likely are collision and rotational stresses. I’d reject the outgassing model because it is so far from the Sun. And if it had rotational stresses existing beforehand, they would have likely already dispersed it to a much larger size, so let’s consider that one not terribly likely, since it would have to have serendipitously happened just before discovery. Possible? Yes. But not very.

    I’d target a collision of P/2013 R3 (as a strengthless body) with a quite small body as a prime possibility. It is, after all, VERY close to the Ecliptic, where the most bodies should be – and the small, undetectable rocks number in the gazillions. This could have done BOTH – dispersed material AND caused rotational stresses. It wouldn’t take more than a rock at a relative velocity of a few km/sec (maybe much less) to jar the body enough for material to start slowly moving away, especially from an off-center collision. Off-center is most likely, anyway. I am talking SMALL. Smaller would mean lower impulse to the P/2013 R3 main body, so the whole thing could happen in slow-motion.

    A peek at Itukawa asteroid shows a non-strengthless body (quite solid, in fact) with LOTS of debris lying on its surface, so let’s consider something in that direction, too. A nudge by a rock could easily jar stuff off its surface and out into a cloud.

    For both possibilities, it is certain that in time the cloud of material could and would re-settle onto the object.

  • Steve Garcia

    Trent –

    Taking up where we left off, about the fragmented vs intact big impactors, I am reading Hills and Goda, 1993 “The Fragmentation of Small Meteors in the Atmosphere.” It’s one of a ton of papers I am trying to get through right now. I can email it to you, full text.

    Abstract:
    The fragmentation of a small asteroid in the atmosphere greatly increases its cross-sections for aerodynamic braking and energy dissipation. The differential pressure across a meteoroid disperses its fragments at a velocity that increases with atmospheric density and impact velocity and decreases with meteoroid density. At a typical impact velocity of 22 km/s, the atmosphere absorbs more than half the kinetic energy of stony meteoroids with diameters, Dm<220 m and iron meteoroids with Dm<80 m. The corresponding diameter for comets with impact velocity 50 km/s is Dm<1600 m.

    If we apply this information to Chelyabinsk, which was 17 m across, we see that this is what happened. All that flaring along its path was not only simply material ablating, but energy being removed, too. The papers about it talked about it having lost 90% of its energy before the flaring.

    So, if 1/2 of a 220 meter stony meteor’s energy is “absorbed” by the atmosphere, does 90% of a 17 meter stony meteor sound about right? I think so.

    The Abstract continues:

    Most of this energy dissipation occurs in a fraction of a scale height, which causes large meteoroids to appear to “explode” or “flare” at the end of their visible paths.

    The important phrase I think is “appears to.”

    The dissipation of energy in the atmosphere protects the Earth from direct impact damage (e.g., craters), but the blast wave produced by the dissipation in the atmosphere can cause considerable damage to structures on the ground.

    While Chelyabinsk didn’t cause considerable damage, this seems to be true.

    The area of desruction around the impact point in which the over pressure in the blast wave exceeds 4 pounds/inch^2 = 2.8×10^5 dynes/cm3, which is enough to knock over trees and destroy buildings, increases rapidly from zero for chondritic meteoroids less than 56 m in diameter (15 megatons) to about 2000 square miles for those up to 80 m in diameter (48 megatons). (The minimum diameter of the Tunguska impactor of 1908 is about 80 m.)

    ZERO area of destruction of buildings up to 56 meters.

    This is all good news, because it says that if we can fragmentize a meteor down to below 56 meters, the destruction zone is basically zero.

    The area of destruction produced by stony asteroids between 70 and 200 m in diameter is up to twice as great as it would be without fragmentation.

    And this agrees with what I was saying – fragmentizing an object means less total damage, even if all of it still impacts into Earth’s atmosphere.

    Crater formation and earthquakes are not significant in land impacts by stony asteroids less than about 200 m in diameter because of the air protection.

    So below 200 meter stony object will not create much of a land impact crater scenario? I found this quite interesting. At the same time, Tunguska, at 80 meters, never even made it to the ground, so this is at least somewhat in the right. ballpark

    The situation is similar for the production of water waves and tsunami for ocean impacts. Tsunami is probably the most devastating type of damage for asteroids that are 200 m to 1 km in diameter. An impact by an asteroid this size anywhere in the Atlantic would devastate coastal areas on both sides of the ocean. The atmosphere plume produced by asteroids with high-entropy gas forms a new layer on top of the atmosphere. The dust entrapped in this hot gas is likely to have optical depths exceeding Tau = 10 for asteroids with diameters exceeding about 0.5-1 km. The optical flux for asteroids 60 m or more in diameter is enough to ignite forests. However, the blast wave from an impacting asteroid goes beyond the radius in which the fire starts. The blast wave tends to blow out the fire, so it is likely that the impact will char the forest (as at Tunguska), but the impact will not produce a sustained fire. Because comets dissipate their energy much higher in the atmosphere than asteroids, they illuminate a much larger region and the blast wave is weaker, so they are much more effective in producing large fires. This suggests the Cretaceous-Tertiary impactor was a comet rather than an asteroid.

    All stuff worth noting, perhaps.

  • E.P. Grondine

    There is an article on Vance Haynes and the Clovis type site in the current issue of “American Archaeology”.