Forgot your password?
typodupeerror
Space Science

Dinosaurs Died Within Hours of Asteroid Impact, says New Study 862

Posted by CowboyNeal
from the sudden-climate-changes dept.
colonist writes "SPACE.com reports that most dinosaurs were incinerated within hours by the 'heat pulse' of an asteroid impact 65 million years ago. The study 'Survival in the first hours of the Cenozoic' presents a scenario where the only survivors were underground or were underwater in swamps or oceans. All unprotected creatures were 'baked by the equivalent of a global oven set on broil.'"
This discussion has been archived. No new comments can be posted.

Dinosaurs Died Within Hours of Asteroid Impact, says New Study

Comments Filter:
  • by scooby111 (714417) on Thursday May 27, 2004 @06:28PM (#9272157)
    Isn't the whole "asteroid impact" scenario a theory? Doesn't that make this new theory a theory based on a theory?

    We're getting kind of thin here.
  • by another_henry (570767) <slashdot@nOSpAM.henryhallam.cjb.net> on Thursday May 27, 2004 @06:29PM (#9272174) Homepage
    Actually it's well accepted as by far the most likely candidate for what happened. By the way, other theories include the theory of gravity, relativity theory etc... all pretty much proven, ask Hiroshima about E=mc^2 if you don't believe that one :P
  • All the dinosaurs? (Score:2, Insightful)

    by farmhick (465391) on Thursday May 27, 2004 @06:35PM (#9272225) Homepage
    Not having read the article, it's hard to see how one meteorite could bake animals on the other side of the world. After all, this impact wasn't during the Pangea time, when all of the land mass of the earth was joined in one great continent.

    If this is true wouldn't there be a large carbon layer evenly distributed over the earth's surface from that time?
  • Facts? (Score:4, Insightful)

    by Racer X (140445) on Thursday May 27, 2004 @06:35PM (#9272230)
    This article contains the following quote:


    "There's no question over whether an asteroid hit. The roughly 6-mile-wide (10-kilometer) space rock carved out the Chicxulub crater off Mexico's Yucatan Penninsula."


    But fairly recently there was another article posted on slashdot, about the alleged impact having occurred in (what is now) Australia. (check, e.g., here http://www.msnbc.msn.com/id/4969840/ for a similar story.)

    so what is the consensus *really*, in the scientific community? or is there just none?

  • by bstadil (7110) on Thursday May 27, 2004 @06:37PM (#9272242) Homepage
    All science is to some extend bassed on layers of theory, however each new theory, if correctly done, explains all the known facts but often includes elements of predictions along the lines of "If this theory is correct we will expect to see X".

    Now we can go looking for X and if we find it and the prediction was somewhat unexpected before the theory was proposed it is a strong indication of its validity.

    Case in points Einsteins prediction of light being bend by high gravity object that was indeed confirmed.

    Same here if we do find a a lot of different Dinosaurs in the same narrow strada around the world it make the theory more likely.

  • by qkw (755948) <qkwozz@bjcomics.cUMLAUTom minus punct> on Thursday May 27, 2004 @06:38PM (#9272257) Homepage
    so the increase in temperature caused all the female dinosaurs to believe they were menopausal and having hot flushes, and therefore forbade the males from interfering with them?

    sounds like a neat little theory
  • Of course I didn't read the article, as I don't subscribe and am lazy, but wouldn't the heat kill all the plants too? And I thought there were "many" survivors. Mostly small animals, besides plants and lower life forms. And how could 1 impact effect the entire planet with such a high amount of heat? Wouldn't that metemorph rocks as well? Or even react the atmosphere?
  • by kingmundi (54911) on Thursday May 27, 2004 @06:44PM (#9272309)
    1. Do the Americans really have enough nukes to destroy the world ten times over?

    This one I hear a lot. First of all, despite what you may have heard, really the majority of the energy of a nuclear explosion turns into heat and blast immediately, NOT radiation. The only exception to this is the so-called Neutron bomb, designed specifically with radiation (more specifically fast neutrons and gamma rays) in mind. But realistically, although the Americans have built approximately 70,000 warheads of almost 70 different types, they now possess a stockpile of around 9600 warheads. Surprising as it may sound, this is NOT enough to 'destroy' the world. Even hitting every city in the world with everything in every country's arsenal would not be able to 'destroy' the world. The world is still a
    BIG place. Keep in mind the Russians have around the same numbers of warheads.
  • by Daniel Dvorkin (106857) * on Thursday May 27, 2004 @06:45PM (#9272318) Homepage Journal
    Funny, no. But sometimes that kind of dramatic analogy is necessary to get the point across to people who don't understand what the word "theory" means in a scientific context.

    I tend to personalize it a bit: "If you believe that ___* is 'just a theory,' be aware that gravity is 'just a theory' as well. I invite you to try jumping off a skyscraper because, surely, nothing that is 'just a theory' can hurt you."

    *___ is almost always evolution, of course, though sometimes it's relativity.
  • by DragonMagic (170846) on Thursday May 27, 2004 @06:45PM (#9272322) Homepage
    Plus, if it were that powerful to bake animals, would not the water temperature rise, and the air bake the animals which did survive, and destroy the birds as they're not too good about going underwater, and melt the ice at the caps, and...

    Sorry, but this theory doesn't even sound plausible. What could they base it on? (Sorry, article /.'ed)
  • by robogun (466062) on Thursday May 27, 2004 @06:45PM (#9272323)
    Someone post the article so we can make intelligent comments on it.
    To be honest, I have no idea why an article like this is not considered spam, if we have to pay to read it.
  • Why is that sad? (Score:4, Insightful)

    by Kelmenson (592104) <kelmenson&yahoo,com> on Thursday May 27, 2004 @06:46PM (#9272328)
    For those of you not in the military, this means that if the bodies of the dead were to get up again, we could kill them all 12 more times. We humans are capable of creating a much larger catastrophe than our often theoretical cousins in space; and it's saddening.

    The fact that man has the power to potentially do something shouldn't make you sad. It should actually make you proud. Now, if man would actually do it, that would be sad.

    Man can kill man, but until they do, there is nothing to be sad about.

  • by jebell (567579) on Thursday May 27, 2004 @06:49PM (#9272357) Journal
    And just how much stronger could dino muscles have been than modern mammalian muscle? 140% stronger, 170%? That's really stretching it, and it still isn't nearly enough.

    I think you're underestimating how strong many animals really are. Our close relatives, the chimpanzees, are considerably stronger, pound-for-pound, than we are. Reptiles are also noted for being very muscular, even if they don't have much stamina.

  • by ZiggyM (238243) * on Thursday May 27, 2004 @06:55PM (#9272399)
    The seeds could have survived. Many seeds have evolved so survive things like forest fires. Some seeds have a tough protective shell as well, to further increase their survival chances to fire.
  • by Ulumuri (550492) on Thursday May 27, 2004 @06:58PM (#9272416)
    Actually, the fact that you fall if you jump off a skyscraper is the fact of gravity.

    The theory of gravity would be something like F ~ m_1*m_2/R^2.
  • by vaccum pony (721932) on Thursday May 27, 2004 @06:58PM (#9272419)
    "Actually it's well accepted as by far the most likely candidate for what happened."
    In the general public's mind perhaps, but not elsewhere. There is a LOT of fossil evidence showing that Chicxulub did NOT wipe out the dinos. There is also fossil evidence that dinos were already in decline BEFORE Chicxulub hit.

    Before and after Chicxulub Earth was experiencing a lot of volcanic activity. So much in fact, that the compositiom of the atmosphere was changing. As I recall the oxygen content was reducing from 30% down to 24% (I'm sure these are not the exact numbers, but they are close). Less oxygen meant that animals had to work harder in take in the same amount of oxygen. The dinos may have have suffocated.

    Of course, a large impact would not have helped them out...
  • by Daniel Dvorkin (106857) * on Thursday May 27, 2004 @07:02PM (#9272440) Homepage Journal
    Nope, the fact that you fall if you jump off a skyscraper is that fact that you fall if you jump off a skyscraper. Gravity is the theory that says you fall because the Earth, being rather large, exerts a powerful attractive force on your soon-to-be corpse. You could just as easily explain the falling by using the Aristotelian (IIRC) "things fall because it is their nature to fall" -- but that theory proved to be incompatible with the evidence, and thus was discarded; modern gravitational theory is the best we've got, so far.
  • by Anonymous Coward on Thursday May 27, 2004 @07:07PM (#9272478)

    Actually, the fact that you fall if you jump off a skyscraper is the fact of gravity.


    You are assuming that you know what will happen in some unobserved (hypothetical) event. Either you are Psychic, or you are using some theory that seems to have been useful in the past to predict what will happen in the situation you propose.

    Whaddayaknow? You were using the theory of gravity. (the fact of gravity that you speak of is strictly for chumps)
  • by hypnagogue (700024) on Thursday May 27, 2004 @07:25PM (#9272643)
    The fact is that the mass of the water that would be displaced by an animal as large as a sauropod would prevent it from breathing.


    Oh... that's why whales are extinct.
  • by ultramk (470198) <ultramkNO@SPAMpacbell.net> on Thursday May 27, 2004 @07:34PM (#9272735)
    Plus, if it were that powerful to bake animals, would not the water temperature rise, and the air bake the animals which did survive, and destroy the birds as they're not too good about going underwater, and melt the ice at the caps, and...

    To kill most large animals, the air doesn't need to be hot enough to bake the whole animal, just ruin its lungs.

    Plants are easy. Many (most?) plants have evolved mechanisms to allow them to survive forest fires, brush fires and the like. The root stock would survive, and the seeds are mixed with soil/blown into protected places etc. Remember, they don't all have to survive, just enough to repopulate the species. There would be myriad places where plants or animals would be sheltered by the shape of a canyon/cave or whatever.

    There are quite a few bird species that live in burrows/caves/hollow logs etc which would have survived. There are a lot of bird species that respond to any danger by diving into the water, and diving deep. Grebes, cormorants, and the like. There are lots of diving birds.

    As far as raising the temperature of the water, you're vastly underestimating the amount of energy it would take to raise the temperature of all of the earth's oceans. It takes a lot more energy to raise the temperature of a volume of water than it takes to raise the same volume of air the same amount. (any physicists/chemists/engineers want to run the numbers?) The surface temperature of the oceans would probably rise a bit, then most of that energy would be shed back into the atmosphere by evaporation. The overall temp of the oceans would remain pretty constant, certainly not enough to melt the ice caps. For the superheated air directly above the glaciers, there would probably be a little bit of surface melting, which would immediately refreeze, leaving a glazed surface.

    m-
  • by Graabein (96715) on Thursday May 27, 2004 @07:39PM (#9272773) Homepage Journal
    > Man can kill man, but until they do, there is nothing to be sad about.

    - "Hey, we managed to coexist for 40 years without incinerating 500 million people, this calls for a celebration and a congratulatory pat on the back. Attaboy!"

    ??

  • by another_henry (570767) <slashdot@nOSpAM.henryhallam.cjb.net> on Thursday May 27, 2004 @07:39PM (#9272776) Homepage
    If, 5 milliseconds after I die, I believe anything at all, then I will be surprised and change my opinions based on the new evidence. If a vengeful God chooses to damn me for not feeling the same way throughout my life despite lack of evidence, then screw Him.
  • by Ungrounded Lightning (62228) on Thursday May 27, 2004 @07:42PM (#9272794) Journal
    I'll tell you the problem with the scientific power that you're using here. It didn't [re]quire any discipline to attain it. You read what others have done and you took the next step. You didn't earn the knowledge for yourself so therefore you don't take any responsibility for it. You stood on the shoulders of geniuses to accomplish something as fast as you could and before you even knew it you had it.

    So you only "earn" the "right" to make a product if you personally developed every single scientific theory and technological breakthrough necessary to construct it, working from first principles you personally developed?

    Reminds me of how "The New Math" created a generation of ilnumerates by (instead of teaching counting and arithmetic skills) requiring them to invent for themselves the entirety of several millenia of number theory behind arithmetic and mathematics - while being distracted by "helpful" information about multiple bases and the like.

    You stood on the shoulders of geniuses to accomplish something as fast as you could and before you even knew it you had it.

    It was a GIANT who characterized his own scientific breakthroughs as being able to see farther than others because he stood on the shoulders of (previous) giants.

    Following the Ian Malcom character's advice leads to abandoning, not just genetic engineering, but all of science, history, engineering, industrial society, archetecture, farming, hut-building, and even stone knife making. Humanity would be reduced, not just to the level of hunter-gatherers, but to the level of purely instinct-driven animals (below primates, cats, birds, and even some reptiles).

    = = = =

    None of which in any way detracts from your point, which was dead on. B-)
  • by alcmena (312085) on Thursday May 27, 2004 @07:44PM (#9272815)
    You will believe two (sic), 5 milliseconds after you die.

    No offence, but my wife was declaired dead for almost two minutes about 5 years ago. What did she see? Nothin'. She thought she had simply fallen asleep. The one thing she does remember is that her chest hurt like hell from the electrodes though.

    Granted, she's only one data point, and I'm sure you will discount her experience. But I thought I'd share it anyway.
  • by barawn (25691) on Thursday May 27, 2004 @07:49PM (#9272857) Homepage
    But it doesn't. Just in case you missed it: Evolution does not fit your faith, if that faith is God and Christ. If one of the foundations (creationism) of your hypothesis (God and Christ are real) is wrong, then the whole thing is simply WRONG. You can't throw one away and replace it with another.

    Cool. An anonymous coward knows more than the Pope about religion. Arrogant, aren't we?

    The Pope stated sometime in the 1980s that christianity and evolution don't contradict, and that one can easily believe in both.

    Or you can read the very well written commentary here [newsday.com], and get a clue. Using the same stubborn-headed aspect that you bedevil in others makes you just as bad.
  • by smurf975 (632127) on Thursday May 27, 2004 @07:52PM (#9272880) Homepage Journal
    Mammals were the size of mice at those days. And mice tend to feed on small plants and insects. And insects will defently survive a lot of things as people also think that the first land dwelling animals were insects even before land based plants, trees or fish. Also a lot of insects only need to eat twice a year.

    So the mammals could survive. Reptiles are cold blooded and like insects don't need a lot of food. And perhaps only the smaller once survived and they grew that what you are used now. As Elephants used to be little rat like creatures once.

    But what about birds? I think because they could fly (move fast from one area to another), were small and like dino's were hot blooded. They survived.

    I saw once this docu that actually the age we are in now can be called the age of the birds. As they are everywhere even in cities were only humans and rats can survive.

  • by voicecrying (774890) on Thursday May 27, 2004 @07:59PM (#9272947) Homepage
    The theory of gravity can be backed up by experimentation and observation. Evolution cannot. Evolution can never be proven by science. And that goes for the entire array of evolutionary theories.
  • The new study reviewed existing geologic evidence for the known impact and considered interesting patterns in species survival. How did some birds, mammals, crocodiles, snakes and other animals endure the calamity that wiped out larger species?

    That's a good question. But it's got a bug in it - the phrase "wiped out larger spieces". Better to say - selectively wiped out one branch of animals that came in all shapes and sizes, and lived in all kinds of environments right alongside animals that *didn't* die out.

    That asteroid sure was amazing!

    The survivors burrowed underground or were protected from the firestorm by swamps or oceans, says study leader Doug Robertson of the University of Colorado at Boulder. The details were published in the May-June issue of the Bulletin of the Geological Society of America.

    That's so plainly idiotic that it beggars belief. Dinosaurs came in a wide variety of sizes, some smaller than chickens. And there were many aquatic animals that also became extinct, that supposedly would have been safe according to this "study leader".

    Another win for the hypothesis that makes for a good special effect, then. And published by the Geological Society - well colour me not suprised.

  • by Anonymous Coward on Thursday May 27, 2004 @08:31PM (#9273179)
    There's plenty of evidence of evolution out there. I'll go ahead and choose the easiest to see: bacteria. There's a reason that penicillin (and other antibiotics) don't work much any more. The bacteria they used to kill have developed an immunity to their effects. One might even go so far as to say they evolved into a new form of species that is immune/resistant to the effects of antibiotics. There's some evidence for you right there.

    Oh, and just so you know, the theory of gravity hasn't been proven, either. It's just got lots of evidence for it, as does evolution. Theories can only really be disproven, not proven.
  • by John Harrison (223649) <johnharrisonNO@SPAMgmail.com> on Thursday May 27, 2004 @09:04PM (#9273398) Homepage Journal
    A recent asteroid impact article on /. pointed out something that I had never thought of before. The two worst places to be after a major impact are under the impact and on the opposite side of the planet from it. Why is this? The debris that the impact throws up will travel out from the site of impact and some bits will go a long ways and other bits not so far. In any case, if you are 1/4 of the circumference of the earth from the site the debris can only come from one direction, but if you are 1/2 the circumference of the earth from the impact (opposite side of the earth) debris will be coming in from all directions. Some won't make it that far and some will fly even further, but it is the most likely place to get hit.

    This is easy to visualize if you imagine a strike at the North Pole and the debris traveling along the lines of longitude to the South Pole.

  • by ThosLives (686517) on Thursday May 27, 2004 @09:19PM (#9273471) Journal
    Unfortunately this is replying to an AC, but hopefully this thread is still live enough for others to read this.

    The AC says:

    There's a lot to know about being Christian (really a lot to read), but it all relates to two fundamental rules or commandments:

    1. One must love GOD more than anything else.
    2. One must love others like oneself.

    The AC, is in fact, quite mistaken. What he quoted here is not the core tenet of Christianity; this is just a nice way to live with God thrown in for good measure. What Christianity is is this:

    God and mankind had a good releationship, but this relationship was broken because people choose to live without acknowledging God. People are incapable of reconciling this relationship, so God, because He loves people, sent His son Jesus Christ to die on the cross and suffer horribly as a reconciliation so we can have a restored relationship with God. The restored relationship with God is what allows people to actually succeed in loving others and God...

    That is the core of Christianity; not the Pope, not communion, not hymns, not going to church every week, not even the Bible. You can verify this for yourself, it's not some "theory" about Christianity - you should be quite able to go pick up a Bible and read it and you should see this is the case, and if you are so inclined, I'd recommend it.

    As a man who has decided to commit himself to Christ, I kind of am distressed and saddened by the fact that people do not really understand my faith and lump it in with "you narrow-minded American Christian!". Especially since I am a scientist, love physics, and don't see a conflict between evolution and a universe created by God (if God is all powerful, why can't He use evolution?)

    Anyway, at least I hope that you have an understanding now that the common perceptions of "Christianity" might not be universally accurate. Another instance of "don't believe everything you see on TV! (or read on /.!)"

  • by letxa2000 (215841) on Thursday May 27, 2004 @09:44PM (#9273650)
    I'm a Christian and I believe that creationism and evolution don't necessarily contradict. However, I do have problems with evolution in that it doesn't make sense. How did a simple but robust single-cell organism spontaneously "evolve" into a more complex multi-cell organism? Why did organisms that reproduced asexually "evolve" into creatures that require a male and female component which is far less efficient? And if one of those spontaneously evolved into something that required a mate, what's the probability that it just happened to bump into another similar organsim that also just spontaneously evolved into the opposite gender of this new mutation?

    I'm a Christian and I'm fully ready to believe in evolution--and I don't entirely discard it. But something just doesn't make sense there, and it's not the religious angle that causes me grief.

  • by Yorrike (322502) on Thursday May 27, 2004 @10:38PM (#9273959) Homepage Journal
    Or, indeed, how actual dinosaurs are still around [geocities.com], and have remained unchanged for the past 80 million years.

    Now true, tuataras are burrowing animals, but they have to leave their burrows to feed on the insects they love so much.

    Don't even get me started on birds. This theory has so many holes in it. If the Earth was grilled as the report suggest, then where's the geological evidence? A thin layer of carbon circa 65 million years ago representing all the burnt land flora?

    Even the author admits it doesn't account for the mass extiniction that also took place in the ocean.

    So what do we have? A theory that has no direct evidence to support it, has huge holes, does not fit with the observed evidence we've been collecting for the past two hundred years, and is incomplete according to the author. Nice one.

  • by newhoggy (672061) on Thursday May 27, 2004 @11:11PM (#9274139)
    Umm, seeds?

    Exactly! Evolution put a lot of effort (so to speak) into evolving seeds that refuse to germinate unless the conditions are just right. Germinating only when conditions are right maximises the chance of survival for the plant.

    I had a packet of cactus seeds with instructions to soak them in very hot water for one minute, plant them immediately afterwards in moist sandy soil and leave them in the dark for a week or so. Even so, mine didn't germinate until three weeks later. Fussy little buggers they are.

  • Re:Broil? (Score:2, Insightful)

    by Anonymous Coward on Thursday May 27, 2004 @11:20PM (#9274175)
    Broil is a horrible word, brings up images of boiling meat and then just serving it.

    Which, of course, produces a meal just as flavorful as your average British meal!

    Point of fact-- broil goes back to Middle English [m-w.com], which, as far as I know, was never spoken in America.

  • by geekotourist (80163) on Thursday May 27, 2004 @11:59PM (#9274354) Journal
    Because, cladistically speaking at least, birds are dinosaurs [berkeley.edu], most closely related to the Dromaeosauridae like the Velociraptor [berkeley.edu].

    The extinction event killed off all species larger than about 20kg. That wouldn't have included any mammals. Mammals 65 million years ago were tiny (mice sized) and most likely nocturnal.

  • by peawee03 (714493) <mcericks AT uiuc DOT edu> on Friday May 28, 2004 @12:03AM (#9274377)
    Where in the Bible does it say, for a fact, that evolution cannot coexsist with creationism?

    Hell, the timeline for the Book of Genesis and the big bang theory more or less coinside, just the scales are different.

    Oh, and I'm sure I'll end up believing in something after I die. It's just what that's the problem. Most of my Hindu friends think this talk of heaven and hell is quite funny... "if at first you don't succede..."
  • by Artifakt (700173) on Friday May 28, 2004 @12:30AM (#9274517)
    Domestication is by artificial selection. That theory some people disagree with isn't really called evolution the way Darwin wrote it, it's much more properly called natural selection. This is to distinguish it from at least one major theory of evolution that has been very largely disproved only in the last century(Lamark's Theory of eveolution by inheritance of acquired characteristics, see also Lysinkoism), and may be necessary to distinguish it from some other variants still floating around in the zeitgest.
    One of the problems some people have with the Darwinian theory, is it is too often presented as "All selection is natural selection" or "Natural selection is sufficient to account for all observed variation", which is precisely what you yourself just offered a fine counter-example to. Proof of natural selection would be better based on those wolves you bring up towards the end, but the evidence there is in the line that extends backwards in time from the modern wolf to the varois proto wolves, rather than the branches off that line that make up domestic dogs.
  • by shadowbearer (554144) on Friday May 28, 2004 @08:30PM (#9282374) Homepage Journal
    Um, sorry, but no; and neither of those articles support your hypothesis of antipodal debris concentrations, either (as a matter of fact the first one notes that the majority of the high-energy debris would fall within a couple thousands km in a pattern distributed to the *west* of the impact, due to the Earth's rotation)

    Debris concentrations would have a circular modified to oval distribution around and to the west of the impact crater that would somewhat resemble an interference pattern. There would be no antipodal concentration because most of the really high energy debris is thrown almost straight up, not to the much more acute angle to the Earth's surface that would result in the concentrations you describe. Actually it's likely that little debris would reach the antipode, as debris that was that energetic would either go into a highly elliptical orbit (randomizing the fall distribution) or escape Earth entirely (as the first article notes)

    However, the shockwaves that would travel along the Earth's surface would experience peak(s) at or near the antipode; not anywhere near as much of one as would happen on, say, Mercury (which is more near a perfect sphere and doesn't have anywhere the variations in surface/mantle density that the Earth does). This phenomena has been theorized to have resulted in some formations on Mercury -and to a lesser extent, the Moon - but those formations have nothing to do with debris distribution, rather shockwave intensity peaks). To what extent shockwave concentration at the antipode would occur on Earth is yet unknown - it's bloody difficult to model.

    I could probably find all kinds of links to support what I'm saying here, but it would take a lot more time than I have right now. I'd suggest doing some further reading; there are some really good books/articles/papers out there on the subject - if you can handle the math, which is tortuous.

    In any case what I posted is still pretty much a simplification...

    I'm not posting this to flame you, but you are visualizing it wrong. Trust me - I've studied this stuff both in school and as a hobby for nearly a quarter century. Guess I just hate seeing an obviously smart and imaginative person misreading something :)

    Cheers,
    SB
  • by shadowbearer (554144) on Sunday May 30, 2004 @09:08PM (#9293102) Homepage Journal
    Sorry for the late response, it's been a long weekend...

    Yes, I saw those quotes. But those are statements by third parties, not support per se. There are better links, like this one [arizona.edu] for support purposes (and see below )

    That said, I have some problems with Melosh (and Kring/Durda)'s models. For one thing (as can be clearly seen in the gif on the link I provided) they postulated wildfires from impact debris in an area that at the time included very little land; and we have no way of verifying the computer model that they used for impact debris distribution from geological data.

    Hence, my reaction to it; and sorry, I didn't mean to berate the messenger. :)

    In any case, I've read about Melosh's work before, and I find the mathematical models he used somewhat suspect - but I'll withhold further judgement on that until I can obtain a copy of his paper (which a friend of mine is mailing me this week, got interested enough to request it rather than reading the thirdparty-etc abstracts.) Like I said, the math is tortuous; and a lot of the effects of those impact energies are not as well understood as we'd like.

    I am not saying that it won't All I am saying is that debris will fall at the antipode in a grearter concentration than other distant locales. Are you saying that none of it will reach the anitpode? Are you also saying that none will reach orbit?

    Um, no to either question. As to whether debris in an earth impact would have a concentration at the antipode is still pretty much conjecture backed by a couple of computer models. Personally, I disagree with it; at least I don't think (not having seen his paper yet I can't make a stronger case than that) that he's modeled all the factors correctly, such as impact obliquity, high-altitude wind factors, gravitational variations effecting debris suborbit trajectory, suborbital atmospheric variations, etc, blah blah blah :).

    Of *course* some of it will reach the antipode. Whether there is a relevant concentration there is what I debate; it's not proven to my satisfaction, not yet, anyway. Orbital mechanics postulates that a portion of the debris may land there, but I think I've already dealt with that.

    As to whether it will reach orbit, it's pretty easy to show that a fair amount (10% or so according to the models) will not only reach orbit but be ejected from the Earth-Moon system entirely (and that 10% figure of course depends a great deal on the impact obliquity and whether or not it impacts deep water or land, and also on the impact energies - a 10-20 km body is borderline in that respect, additionally, impact velocity is a lot more important; KE=mv^2, and we don't have *any* even semisolid figures as to either.)

    I guess what got me about your post was that you linked to a couple of sites that merely mentioned the antipodal debris effect, and not to one that was from the horse's mouth, so to speak.
    The reason I talked about the shockwave effect a lot is because extremely good evidence for it has been found on other planets (and possibly even here, the Permian event and the Deccan trap eruptions are a good example), and I feel that shockwave concentration in the K-T event probably accounts for a lot more geophysical effects than debris concentration - and yes, I'm aware that some circumstantial evidence has been found for debris concentration effects on the moon [google.com.ni] (fascinating reading in itself, scroll about halfway down), but impact debris distribution on the earth is going to be entirely different than it will be on a smaller body with no atmosphere.

    It was also late, and I was tired, and probably not thinking clearly :)

    Anyway, having googled it a bit, I'd sugges

HELP!!!! I'm being held prisoner in /usr/games/lib!

Working...