I came across a well-researched and informative blog today summing up the recent findings and YDB science to date. I was so impressed by Abby Tabor’s post at Science Works Now, “New Evidence for Climate-Changing Cosmic Impact,” I have added a permanent link to her on the side-bar.
Tabor it seems was driven — shudder — to actually contact the authors on each side of the YDB hypothesis debate and ask them what they think. She has informative communications from both sides:
van Hoesel
Their nanodiamond analysis also suggests a later origin for these particles, based on their position in the layer and their physical association with glass-like carbon, a product of wildfire. van Hoesel concedes that the nanodiamonds could have formed earlier and only later become stuck to the other carbon particles, although she considers it unlikely. She speculates that perhaps an as-yet-unknown process exists for the formation of nanodiamonds at the relatively low temperature of a wildfire. This has been observed in experimental set-ups; if the phenomenon could be found in nature, it might offer an alternative to the cosmic explanation.
Richard Firestone, one of the originators of the impact hypothesis, is not in the least deterred by the Dutch study. He claims their carbon-14 dates are “unacceptably precise”; if the error were larger, as he feels it should be with this technique, both groups’ dates would coincide. According to van Hoesel, though, the error is in line with other studies published in the field. The disagreement shows the importance of careful analysis of the numbers. Firestone also contends that, had the two groups used the same system of radiocarbon date calibration, the dates assigned to the impact and the Dutch wildfires would have been nearly identical. “In my opinion the van Hoesel paper supports our research. They find nanodiamonds at or near the date of the YD impact. There is no other accepted theory for the formation of nanodiamonds found in a narrow layer around the world. No nanodiamonds are found significantly above or below the YD layer. van Hoesel misinterprets the distribution of nanodiamonds near the YD which is affected by [stirring up] of the sediments by wind and rain. Typically nanodiamonds tend to rise in the sediment appearing a bit younger than they are.” Firestone finds that “most of our critics first confirm our work and then try to ascribe it to nebulous other causes.”
Bunch
A 2011 article, “The Younger Dryas Impact Hypothesis: A Requiem” traces the history of this research and purports to put the question, finally, to rest. However, Ted Bunch, co-author of the impact hypothesis and former Chief of Exobiology at NASA Ames Research Center, observes that this scientific memorial service “presented little original evidence. Rather, they criticized non-peer reviewed documents. Their arguments were answered rather well”, he adds, by the 2012 paper from Israde-Alcántara I, et al., providing evidence from central Mexico in support of the proposed Younger Dryas cosmic impact.
(Before I have gone to the other site…)
The main thing here is the give and take of inquiry re a newly posited explanation for puzzling evidence. It wouldn’t be a puzzle if one side had all the answers. Van Hoessel is correct to point out the layering, and Firestone is correct in pointing out over-precise precision that is claimed. Firestone is also right to point out the contortions the skeptics are going through in trying to crowbar their interpretations into ANY other explanation than impacts. In politics it is called the “Anybody-But-The-Candidate-We-Despise” approach. Here it is “Anything But Impacts.”
Now, to go see what she has there.
Thanks, George!
At the linked site, the first thing my eyes landed on was “Multidisciplnary Research News.”
As someone who has actually READ Velikovsky (I tease Ed about that), this is a bit of a rip-off of the Society for Interdisciplinary Studies, a pro-Velikovsky site.
In saying that, I am ragging on the same kind of transparent “Anybody-But-____” politics that Firestone talked about. Velikovsky is SO radioactive that any mention of him – or any CREDIT due him – is mealy-mouthed at best and treated as leprosy at worst.
IN saying so, I am NOT defending Velikovsky. His conclusions about Venus and Mars fly-bys were crap. At the same time, it is easy now to look back at Velikovsky 65 years ago and pick on him, when we know so much more now. In 1950 Velikovsky’s ideas should have been addressed collegially. Some of his stuff was of value. So much value that it has been used again and again, without so much as a thank you.
But what has really gone on is that a lot of stuff Velikovsky addressed have been hijacked by others without crediting him at all. As radioactive as he is, that is understandable – but someone has to point out the rip-offs.
So it wasn’t Venus and Mars. Big deal. It is Comet Encke Progentor instead. Velikovsky DID at least call it a comet. Yeah, the comet was Venus, and it may or may not have actually impacted. But in drawing attention to the indigenous accounts around the world, Velikovsky was WAY ahead of Ed and the others of today who are doing the same thing – and finding merit NOW. But in his day, Velikovsky was treated as a pariah for doing the same thing.
So, I see ‘multidisciplary’ and I know that it is “interdisciplinary” without actually saying it. Velikovsky was a forerunner in multi-interdisciplinary research in this area. He will never get credit for it, but copying his work and terms and not using him as a source is pretty feeble.
Again, he didn’t get it all correct, but lots of other scientists – Micheal Mann in climatology comes to mind – totally botched their work and still are highly respected. Being wrong is no reason to be treated like a leper.
In Van Hoessel’s “speculation” (Abby Tabor’s word) about the nanodiamonds being from later fires would have to include an explanation for wildfires all around the world at that later time – a statistical improbability bordering on infinity. Van Hoessel – as George and Firestone point out – pulls this speculation right out of you-know-where – simply because it is a case of “Anything-But-Impacts.” The other terms for all this is “moving the goal posts,” “raising the bar,” or “changing the rules after the game has started.”
This is smoke and mirrors. Those aren’t the only real questions. If it was an impact, it also has to be determined WHAT impacted – a meteor, an asteroid, or a comet. The resistant van Hoessel crowd will drag their feet about it being a comet, stretching this issue past the retirement ages of many of the current impact researchers. IMHO, they want to win by default, just by outlasting the impact researchers. A cometary impact can take so many forms, such as mulitple impacts, air-bursts of friable fragment(s), and can have varying degrees of friability. The permutations are quite numerous, and they will resist each one, probably one at a time. They will make the pro-impact researchers jump through hoop after hoop, no matter how many times their work is borne out by the evidence. They don’t care one whit about winning each battle, as long as they can win the war. For each possible incoming object they will demand an impact site, a detailed description of what exactly happened, precise micrometer readings of its size, and a date as precise as the date van Hoessel claims for her firestorm nanodiamonds.
And as to changing the climate, everyone accepted the tales of “nuclear winter” back in the 1980s without batting an eye. Here we have one or more impacts each of which could send humanity back to the stone age, and which also in total would exceed the entire nuclear arsenals of the world (even at the height of proliferation) by a magnitude or two, and yet, she puts this issue on the board like it is a real issue. Was she not aware of Shoemaker-Levy/9 in July of 1994? Did she not see the size of those fireballs (in the 2.78g gravity of Jupiter)? Van Hoessel is being disengenuous. If our nukes could cause a nuclear winter, then impacts magnitudes bigger can do so without a doubt. Would the changes last 1200 years? I addressed that recently, at least qualitatively, and there should be no doubt that it is a complete possibility. Once in an impact winter, all the processes that drive climate will be thrown out the window, until the climate reaches a tipping point in the convection in the Interconvergence Zone, which drives the Hadley cells which are the first order mechanisms that carry heat toward the poles. Without that convection and the Hadley cells, all current models of the climate are worthless. But when a threshold is crossed (call it a tipping point if you want), the ITC and Hadley cells start working again in pretty short order.
Does all that have to be tested? Of course. But it is at least as likely as what van Hoessel is speculating about.
From BENNY PEISER’S GWF: News About Greenland Ice Cores:
Everything You Know About Paleo-Climate May Be Wrong
Ice samples pulled from nearly a mile below the surface of
Greenland glaciers have long served as a historical
thermometer, adding temperature data to studies of the local
conditions up to the Northern Hemisphere’s climate. But the
method — comparing the ratio of oxygen isotopes buried as snow
fell over millennia — may not be such a straightforward
indicator of air temperature. “We don’t believe the ice cores
can be interpreted purely as a signal of temperature,” says
Anders Carlson, a University of Wisconsin-Madison geosciences
professor. “You have to consider where the precipitation that
formed the ice came from.” –e-Science Earth & Climate, 25 June
2012
The full Article titled Greenland ice may exaggerate magnitude of 13,000-year-old deep freeze By Chris Barncard is on the University of Wisconsin’s website. But they aren’t taking any comments. However Anthony Watts is also running it over on WUWT as ‘We don’t believe the ice cores can be interpreted purely as a signal of temperature’. So there’s a good opportunity to discuss it with some serious climate geeks. Anthony says he’ll post the full PNAS paper as soon as it is released.
The article reads:
Ice samples pulled from nearly a mile below the surface of Greenland glaciers have long served as a historical thermometer, adding temperature data to studies of the local conditions up to the Northern Hemisphere’s climate.
But the method — comparing the ratio of oxygen isotopes buried as snow fell over millennia — may not be such a straightforward indicator of air temperature.
“We don’t believe the ice cores can be interpreted purely as a signal of temperature,” says Anders Carlson, a University of Wisconsin–Madison geosciences professor. “You have to consider where the precipitation that formed the ice came from.”
According to a study published today by the Proceedings of the National Academy of Sciences, the Greenland ice core drifts notably from other records of Northern Hemisphere temperatures during the Younger Dryas, a period beginning nearly 13,000 years ago of cooling so abrupt it’s believed to be unmatched since.
Such periods of speedy cooling and warming are of special interest to climate scientists, who are teasing out the mechanisms of high-speed change to better understand and predict the changes occurring in our own time.
In the case of the Younger Dryas, average temperatures — based on the Greenland ice — plummeted as much as 15 degrees Celsius in a few centuries, and then shot back up nearly as much (over just decades) about 1,000 years later.
“In terms of temperature during the Younger Dryas, the only thing that looks like Greenland ice cores are Greenland ice cores,” Carlson says. “They are supposed to be iconic for the Northern Hemisphere, but we have four other records that do not agree with the Greenland ice cores for that time. That abrupt cooling is there, just not to the same degree.”
Working with UW–Madison climatologist Zhengyu Liu, collaborators at the National Center for Atmospheric Research and others, Carlson found their computer climate model breaking down on the Younger Dryas.
While it could reliably recreate temperatures in the Oldest Dryas — a similar cooling period about 18,000 years ago — they just couldn’t find a lever in the model that would simulate a Younger Dryas that matched the Greenland ice cores.
“You can totally turn off ocean circulation, have Arctic sea ice advance all the way across the North Atlantic, and you still will have a warmer climate during the Younger Dryas than the Oldest Dryas because of the carbon dioxide,” Carlson says.
By the time the Younger Dryas rolled around, there was more carbon dioxide in the air — about 50 parts per million more. The warming effects of that much CO2 overwhelmed the rest of the conditions that make the Oldest and Younger Dryas so alike, and demonstrates a heightened sensitivity for Arctic temperatures to rising greenhouse gases in the atmosphere.
The researchers zeroed in on the Northern Hemisphere’s temperature outlier, Greenland ice cores, and found that the conversion of oxygen isotope ratio to temperature typically used on the ice cores did not account for the sort of crash climate change occurring during the Younger Dryas. It assumes prevailing winds and jet streams and storm tracks are providing the moisture for Greenland precipitation from the Atlantic Ocean.
“The Laurentide ice sheet, which covered much of North America down into the northern United States, is getting smaller as the Younger Dryas approaches,” Carlson says. “That’s like taking out a mountain of ice three kilometers high. As that melts, it allows more Pacific Ocean moisture to cross the continent and hit the Greenland ice sheet.”
The two oceans have distinctly different ratios of oxygen isotopes, allowing for a different isotope ratio where the water falls as snow.
“We ran an oxygen isotope-enabled atmosphere model, so we could simulate what these ice cores are actually recording, and it can match the actual oxygen isotopes in the ice core even though the temperature doesn’t cool as much,” Carlson says. “That, to us, means the source of precipitation has changed in Greenland across the last deglatiation. And therefore that the strict interpretation of this iconic record as purely temperature of snowfall above this ice sheet is wrong.”
By the study’s findings, Greenland temperatures may not have cooled as significantly as climate headed into the Younger Dryas relative to the Oldest Dryas, because of the rise in atmospheric carbon dioxide that had occurred since the Oldest Dryas.
“You can say at the end of the Younger Dryas it warmed 10, plus or minus five, degrees Celsius. But what happened on this pathway into the event, you can’t see,” Carlson says.
It’s a fresh reminder from an ancient ice core that climate science is full of nuance, according to Carlson.
“Abrupt climate changes have happened, but they come with complex shifts in the way climate inputs like moisture moved around,” he says. “You can’t take one difference and interpret it solely as changes in temperature, and that’s what we’re seeing here in the Greenland ice cores.”
The National Science Foundation and Department of Energy funded the research.
Climate proxy reconstructions are neither wrong nor right, Steve, you make of them what you will. On the other hand, nearly instantaneous cosmic impacts are indeed wrong or right, as close to wrong or right than you can be in geology. This is the question that needs to be answered, but whether it is wrong or right something has already been learned in regards to impact proxy reconstruction.
TLE –
Climate proxy reconstructions are, indeed, ambiguous, yet many billions of taxpayer dollars in well over a hundred countries are being targeted by govt policy to address what is called the ‘settled science’ purportedly shown in those reconstructions. The proxies themselves have been – as the ice core paper points out – read with a certainty that cannot be real. The other main proxies – tree ring widths and densities – are somehow read as one-to-one proxies for temperature, even though it is full well known that the very same tree ring widths and densities are read as proxies for precipitation, too (as told in an article on CosmicTusk about bald cypresses in South Carolina – right in the CB zone). This – one measurable feature being a proxy for two independent factors – is a logical and methodological impossibility. No one can definitively say how much the tree ring measurements comes from precipitation and how much from temps. Ergo, the claims of tree rings being reliable proxies for either precipitation OR temps is fallacious.
So far we don’t have a great number of people who agree with you on cosmic impacts being “as close to right or wrong than you can be. [sic]” It is a nice sentiment, and one I myself share, but its certainty one way or another has along way to go before being resolved. Yes, the question needs to be answered, but to get to a resolution of that question, many precursor questions need to be resolved to any great satisfaction. For you and the rest of us here, “it has already been learned,” but I doubt you could get Daulton or van Hoessel or Pinter to agree. It is proceeding step-by-sporadic-step, and that is the best we will probably achieve, with our only real satisfaction being that it is moving TOWARD the impact hypothesis and not away from it. It’s gratifying that one or two of the opposition have been more and more convinced of some of the markers’ “impact validity.” But it is not a sealed deal whatsoever.
The proxies themselves have been – as the ice core paper points out – read with a certainty that cannot be real.
The isotope proxies can indeed be read with a known uncertainty, the question is not that they are not precise enough, but rather what they mean.
However, climate science is not based upon isotope proxies alone, or even at all. Tney are merely an indicator of change. You are far from overthrowing climate science, and do the impact community a disservice with your ramblings here.
I think what Carlson and company are saying is that there is an atmospheric circulation component to the moisture stream that comes with the decaying of the deep Des Moines, Superior, Green Bay and Lake Michigan lobes, along with the rapid decay of the Eastern, New England and Maritime sectors of the Laurentide Ice Sheet, that greatly affected Greenland preferentially.
I guess that only makes sense in that it is downwind. That’s where they find all the nanodiamonds too it seems. However, certainly one can’t discount the fresh water forcing and sea ice feedbacks as well. And this certainly doesn’t invalidate the Younger Dryas as a climate changing cooling event.
On the subject of impact proxy reconstruction, has anybody checked out what Madden has been up to lately?
http://faculty-staff.ou.edu/M/Andrew.S.Madden-1/
I think I read where he salted some sediments and was able to recover the particles reliably at a known concentration.
Here is some highly relevant modern new work related to the isotope proxies from the Greenland ice sheet cores.
http://adsabs.harvard.edu/abs/2012EGUGA..14.8539P
I guess you’ll have to search for it.
High resolution water stable isotope profiles of abrupt climate transitions in Greenland ice with new observations from NEEM, Popp, T. J.; White, J. W. C.; Gkinis, V.; Vinther, B. M.; Johnsen, S. J., EGU General Assembly 2012, held 22-27 April, 2012 in Vienna, Austria., p.8539
The paper referenced by Dennis is also online now.
http://geoscience.wisc.edu/geoscience/wp-content/uploads/2011/05/liu_pnas_2012_YD_CO2.pdf
IF a cosmic impact participated in all of this – it would have left evidence of flooding.
That’s my take on the big picture.
Thomas,
I’d be interested to hear your take on how all the ET impact markers, and very high temp blast-effected materials, got concentrated into the YDB all over the world if a comsmic impact didn’t participate in it.
Also, where do you expect to see evidence of flooding? By what bodies of water? And dated to when?
The fresh water North Atlantic and Arctic forcing and/or flooding necessary to disrupt the THC and MOC enough to force the bipolar see saw … er swing. An atmospheric disruption is very brief.
If you subscribe to the theory that the alleged large Younger Dryas impact had no long term climatic effect then you don’t have to worry about this mysterious Lake Agassiz depletion event.
But if you ascribe to the theory that the impact was of the type that can change climate, then there must have been a mysterious flooding event at that time associated with that impact, because like I said, an atmospheric catastrophe does not appear to suffice to describe the data.
It just happens there is a mysterious flooding event, and so I’d like a lot more data and indeed more independent confirmation that the impact proxies are a valid quantitative indicator.
Tom said:
I’m thinkin the full scale, and actual mechanism of the "atmospheric catastrophe" has to be determined before it can be said that it "does not appear to suffice to describe the data".
And since it is Getting clearer with each new paper that the blast-effected materials that have been getting dug up from the YDB are describing a different kind of impact mechanism from anything that’s ever been studied before, then before anyone can really say they’ve got a handle on the scale of what happened, first we’ve got to get a solid handle on just exactly what hit this fair world of ours if it was something so darn different.
If you can’t describe a beast you have no chance of predicting what it’s footprints look like; much less tracking it.
Dennis, an impact that you are describing would have affected the integrated Earth living system for 13,000 years or even 130,000 years, and we would still be living with the effects of it today, but what the data describes is a subtle return to near ice age conditions in the northern hemisphere that abruptly reverted back to Bølling-Allerød like interglacial conditions almost immediately after that very long but relatively stable period of time had passed. No impacts do that on simple physical reasoning. This sort of thing requires a bigger ‘switch’. An impact could be capable of hitting the switch, but an impact is not the actual switch in this case. That much I’m pretty sure of. You can’t describe a thing in terms of things you don’t know, but there are things that I know about the Younger Dryas, so I’ve got to work with that. If a cosmic impact occurred, and I am no means even sure of that, then it must have hit a THC/MOC switch, and that would have left easily discernible evidence. And indeed, I see evidence of some event releasing a large amount of water from Lake Agassiz well before Lake Superior was cleared of all its ice, so much so that it left marks of sub glacial and super glacial discharge channels on the bottom and everywhere else in the immediate vicinity.
Until I see evidence otherwise that’s my position.
Dennis,
a different kind of impact mechanism from anything that’s ever been studied before
Could we investigate the “different kind of impact” through a simulation program? This would have to be vastly more ambitious than what Boslough has done so far. Begin by modeling comet debris streams, my favorite image of “barge loads of gravel” at cosmic velocities (inadequate as you pointed out) creating high amp plasma currents, and on and on . . .
I like the "barge loads of gravel" image too Herman. But I’m also thinkin in terms of a few hundred barge loads of fine dust and sand for every load of gravel sized stuff.
If I had the resources to get those kinds of models done I would use the fragment size and cluster density we see in images of Linear. But what about chemical composition?
Since just about everything we know about comets, and their composition comes from a few fly-by missions we really don’t have the data we need yet to do those models right. As for me, I am impatiently waiting for the results of Europe’s Rosetta spacecraft when it arrives at comet 67P/Churyumov-Gerasimenko to land a probe on it.
That mission will be the first to land on an active comet and accompany it through perihelion. And it should answer many puzzling questions about the chemistry and composition of the kind of object we need to build some of those new models around.
Guys, for a new contribution to the impact debate check out a new book BEFORE THE DELUSION by Wm Gleeson recently published in UK [avail on Amaz]
Gleeson has done a nice job of assembling a lot of old [and new] literary and archaeological info into a very readable story…a page turner…but its impressively researched and documented with some startling new conclusions
worth a look.
RossMelb
Wow.
How is it that by disagreeing, you guys can completely explain what happened!?!
Dennis,
Q1: What does a hundred barge loads of sand for every barge load of gravel do to the upper atmosphere upon 30 km/sec contact?
A1: Heating. Astronomical heating. Over a subcontinental area.
Q2: What does astronomical upper atmospheric heating applied approx simultaneously over subcontinental area do to the surface?
A2: Substantial SURFACE HEATING due to strong irradiative coupling over that subcontinental area. Think about view factor and standing close enough to a forest fire that it covers half you field of view. Then turn up the heat to “Sun Surface” setting on the dial.
Q3: What is the surface effect of that form of impact?
A3: All the smaller bits don’t get near the surface, so mostly no craters or even airburst scarring. Mostly. Over most of the mid-latitudes, large scale fires at the surface, oh yeah! Instant sun burn. Delivered at the speed of light from the IR release overhead. Bargeloads.
TLE,
Naturally a single or few ET impacts do not a 1400 yr cold snap make. And your clearly stated summary to that effect is exactly the right answer on this forum right now, at this point in the history of this debate. Beautiful! So for you I have a different set of questions….
Q1: How many decades or centuries does it take for Earth to sweep out substantial mass fraction of an Earth crossing debris stream?
A1: Many hundreds of years minimum, depending on the helio-period of the debris stream and the distribution of mass along that stream. Each crossing being a light switch, turnend on then back off. Click, click.
Q2: What do we get on a continental ice sheet EVERY TIME we flash heat half a million square miles of upper atmosphere above that ice to FIVE THOUSAND degrees?
A2: Lots of melting ice.
Q3: Where does all that water go? (my favorite question!)
A3: You make the call. I’m guessing some goes East into the Atlantic basin. Complete guess!
What does this bargeload scenario (times 100 per light switch cycle) do to background levels of ET markers? It messes with them to make skeptics sleep better in their assumption that ET impacts don’t effect climate (at least not recently). And X-rays don’t cause cancer.
What are comets made of, where do they come from, what happens to them during their orbital cycle? Where did all the water in the solar system come from!?! On Mars? In the walls of the perpetually shadowed Shackleton crater at the South pole of the Moon, but not so much on the floor of that crater?
These are the questions we need to answer as a species if we wish to remain as such. Define in detail the Helio-Hydro cycle. Study comets. Closely. Land on them and party with them. Hang out at the same bars they do.
So its all the same problem. Geo. Space. GeoSpace.
Want to know where the black mat comes from? Study the Oort cloud. If we can’t look both down (Earth) and up (Space) at the same time, we will never find the full truth.
Earth formed in space. Earth IS THE IMPRINT of that constantly active formative process. Often left alone for long periods of time, Earth has definitely been visited w/ punctuated ferocity by wreckless speeding drivers. Denying that is to assume the role of the turtle slowly crossing the highway. Eventually there will be more traffic….
Thomas Harris
Tom Harris Asked:
Once you factor in the natural orbital precession of that debris stream than you realize that it’s not so much a question of the Earth “sweeping out a substantial mass fraction” of it. But rather how many centuries it takes for the Earth’s orbit to get the hell out of the way of either the ascending, or descending nodes, of the highest concentration of fragments.
For the Taurids you get a few centuries of heightened impact activity followed by something like 7000 years of relative peace before all hell starts falling out of the sky again. This is the founding principle behind the term “Coherent Catastrophism”.
Dennis,
“Coherent Catastrophism”
about which posted dated Sun, 06 Jul 2003 11:03 EDT on another blog there is news, old news, nine years old, an excellent summary by Phil Burns:
http://www.sott.net/articles/show/147246-Clube-and-Napier-Coherent-Catastrophism
Also:
http://star.arm.ac.uk/~aac/zetataur.html
regarding Taurid debris stream intersecting Earth orbit, diagrams & text.
On the subject of how long it would take a massive cloud of cometary dust to clear out of the inner solar system, here’s some food for thought.
http://news.sciencemag.org/sciencenow/2012/07/poof-planet-forming-disk-vanishe.html
Maybe not as long as we might have thought.
Another excellent portal for recent discoveries in astronomy and GeoSpace science (plenty goin’ on in those fields these days) is SpaceDaily dot com.
It’s updated weekly on Sundays so I hit it late Sunday nite or Monday am.
TH
It seems more likely that dust would be ‘collected’ faster than ‘dispersed’ in terms of trying to account for that insanely fast 2 yrs for a vanishing infrared dust signature, but I could see it being pushed out by stellar wind more likely than falling into the star. Fascinating puzzle. The question is really, what was the nature of the ‘dust’ or whatever it was, before it disappeared. The article just has an artist’s conception, so I wonder how much of a signature they got on it and what details, before it vanished. Maybe the star has a small wind envelop in the local interstellar wind, and so it didn’t have to blow the dust too far out for it to be carried off and cooled off.
It would also be interesting to see the working model of proto-Earth impact of Lunar origin to study further where the Earth/Moon escape portion of the ejecta goes relative to the Sun over some years after that event. Does it hang around or get blasted out toward the heliopause? Hard to imagine anything bigger than dust getting much radial acceleration from stellar wind, unless the ballistic coefficient is very low (dust vs. rocks vs. boulders). Over the long term is a different story, but a two year time scale? it would have to be very fine grained I imagine.
So dust vs. heavier chunks is an entirely different story. With a comet in the inner solar system flying by the Sun, some stuff blows away as vapor and dust, while some structure seems to be left behind in a lower density status after that outgassing/venting. Naturally the comet landing mission will yield some quantitive goodness on this topic if all works out. But the fact that we’ve seen a comet pass within one million miles of the Sun and come out the other side says plenty about raw size and robust structure to survive that environment for even a single pass. Frightening. Really makes me wonder about rocky cores and what not. We need density cross section data.
Using the Herschel telescope, NASA determined in 2011 that the Kupier object Comet Hartley 2 has essentially the same heavy hydrogen isotope ratio as water on Earth, where the previous 4 cometary objects measured, all from the Oort cloud, ten thousand times farther away from the Sun than the Kupier objects, had distinctly different heavy H isotope ratios from Earth’s water:
http://www.nasa.gov/mission_pages/herschel/news/herschel20111005.html
“Herschel detected the signature of vaporized water in this coma and, to the surprise of the scientists, Hartley 2 possessed half as much “heavy water” as other comets analyzed to date. In heavy water, one of the two normal hydrogen atoms has been replaced by the heavy hydrogen isotope known as deuterium. The ratio between heavy water and light, or regular, water in Hartley 2 is the same as the water on Earth’s surface. The amount of heavy water in a comet is related to the environment where the comet formed.”
“Our study indicates that our understanding of the distribution of the lightest elements and their isotopes, as well as the dynamics of the early solar system, is incomplete,” said co-author Geoffrey Blake, professor of planetary science and chemistry at Caltech. “In the early solar system, comets and asteroids must have been moving all over the place, and it appears that some of them crash-landed on our planet and made our oceans.”
One of those waking moments when science takes a closer look and finds something unexpected, different from what was previously assumed. Refreshing. Yet in this case, strangely unsettling. What is going on with the hydro-helio cycle? Suddenly a hot topic in modern science! Imagine the timing of that little gem, given what’s cooking in the Catastrophist camp stove.
I believe we are suddenly becoming more self aware, as a species, of our environment. Good thing. Situational awareness never hurts on the astronomical scale.
TimH