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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.'"
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Dinosaurs Died Within Hours of Asteroid Impact, says New Study

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  • Re:Broil? (Score:3, Informative)

    by sense_net (755855) on Thursday May 27, 2004 @06:29PM (#9272169)
    Broil is when you put the food directly under the flames.
  • Article title (Score:4, Informative)

    by SageMadHatter (546701) on Thursday May 27, 2004 @06:35PM (#9272226)
    Dinosaurs Fried Within Hours of Cosmic Collision, Study Concludes

    According to the article, the dinos were cooked by super-heated air. That would mean they were broiled, not fried :)
  • Re:2 Marks from.... (Score:5, Informative)

    by turgid (580780) on Thursday May 27, 2004 @06:37PM (#9272246) Journal
    What they don't teach imperial there?? but we're supposed to learn metric??

    Gas Mark is a Fahrenheit scale.

    From this chart [godecookery.com] it is possible to infer that Gas Mark 0 is 250 Fahrenheit, and each increment of 1 Gas Mark is equal to 25 Fahrenheit degrees.

    So at what Gas Mark setting did they bake/flambe the dinosaurs?

    As an exercise for the interested reader, using spectroscopic data, estimate the surface temperature of Zubenelgenubi in Gas Mark.

  • Re:Facts? (Score:5, Informative)

    by WhytTiger (595699) on Thursday May 27, 2004 @06:38PM (#9272254)
    the consensus is: The asteroid that killed off the dinosaurs is the one that hit in the Yucatan Penninsula The asteroid that killed off 99.9% of life before the dinosaurs existed was the one that hit near austrailia
  • by f97tosc (578893) on Thursday May 27, 2004 @06:38PM (#9272255)
    Isn't the whole "asteroid impact" scenario a theory? Doesn't that make this new theory a theory based on a theory?

    It is widely accepted that an asteroid fell down around 65 million years ago and that this approximately coincided with the end of the dinosaurs (except for birds). You will not find a single serious scientist who disagrees with this.

    What is more controversial is how quickly they died off and if it was only because of the asteroid or if other factors were involved as well. This latest claim is that it was quick; we will see how well it will be received in the scientific community.

    Tor
  • "Alvarez Hypothesis" (Score:5, Informative)

    by Hamster Lover (558288) on Thursday May 27, 2004 @06:43PM (#9272298) Journal
    "Alvarez Hypothesis" is the term used to describe the idea that dinosaurs died as a result of a catastrophic asteroid impact. I do not believe that the hypothesis has attained the status of theory, however. The main evidence for such a hypothesis seems to come from the observation of geologist Walter Alvarez of a significant layer of Iridium on the Cretaceous-Tertiary boundary (KT boundary), due to the fact that Iridium is a very rare element on Earth but found in abundance in asteroids and meteorites. This link [priweb.org] has some more information along with Wikipedia [wikipedia.org].
  • Re:Facts? (Score:5, Informative)

    by MoralHazard (447833) on Thursday May 27, 2004 @06:47PM (#9272334)
    I think you're talking about two different mass die-offs. The Yucatan crater theoretically caused the Late Cretaceous die-off (approx. 65 million years ago) that made the dinosaurs go extincet. The Australian crater has been linked to the Late Permian die-off, which happened about 250 million years ago.

    So, Racer X, the scientific community would appear to have two consensuses (consenses? WTF?), one on each of the two issues.

    Mass extinctions are a fairly regular event in the Earth's geologic history. There are at least two more, besides the Permian and Cretaceous catastrophes, with which I'm familiar. Most people only get taught about the Cretaceous one in high school, though, so they never hear about the others.

    Kind of like the Ice Age. Up until I was 16, I only thought there was one. Turns out there were a shitload of them.
  • Not really. (Score:3, Informative)

    by aepervius (535155) on Thursday May 27, 2004 @06:48PM (#9272345)
    Think about it. The rest are not carbon, if there is complete incineration, then only some non carbonic element are left (Ca, OS, etc...). If the frying is not complete, the bacteria in the body then start their work and eat up the corpse. As for baking on the other side of the world, it really depend on the energy of the impact. It heat up the atmosphere which then in a heat wave travel around the globe. Whether the heat wave is enough is another question which the article seems to answer : yes.

    But as the article point out, this theory does not explain the water extinction of the animals.
  • Re:Facts? (Score:4, Informative)

    by anrwlias (783535) on Thursday May 27, 2004 @06:56PM (#9272404) Homepage
    You are confusing two different craters. The Chicxulub crater is generally considered responsible for the KT (Cretaceous/Tertiary) extinction that killed of the dinosaurs. The newly alleged impact crater off of Australia (there's still controversy over whether it is, in fact, an impact crater as opposed to the remnant of a volcano) is being considered as a cause of the P/T (Permian/Triassic) extinction that happened approximately 251 million years ago. The Permian extinction is notable for being the largest mass extinction on record. Some 95% of all species apparently died out in less than a million years (how much less is a source of controversy). This compares to only 50% for the K/T extinction.
  • by spacecowboy420 (450426) * <rcasteenNO@SPAMgmail.com> on Thursday May 27, 2004 @07:01PM (#9272434)
    I am not sure I could find one - your comment, you back it up.
  • by DuckWing (19575) on Thursday May 27, 2004 @07:06PM (#9272469)
    I really don't care what you think of my intelligence good or bad. I'm stating what I believe to be true. If you read the rest of the posts here, not everyone believe this dribble either. Just because I say, "I believe in Creation" you come up with these insults.

    Well. Not much I can do. But I will say this, You will believe two, 5 milliseconds after you die. Mark my words, and remember them well. They will come back to haunt you at the end of time. Whether you want to believe it or not, is irrelevant.
  • by jomas1 (696853) on Thursday May 27, 2004 @07:09PM (#9272492) Homepage
    Insects are much older than any vertebrate.

    Look at this link http://www.pubmedcentral.nih.gov/articlerender.fcg i?artid=281984

    and this one created by honey bee farmers

    http://www.angus.co.uk/bibba/bibborig.html

    Bees are almost as old as flowering trees which are much older than dinosaurs.
  • by RedWizzard (192002) on Thursday May 27, 2004 @07:25PM (#9272654)
    Of course I didn't read the article, as I don't subscribe
    The space.com article would have answered your questions.
    And how could 1 impact effect the entire planet with such a high amount of heat?
    It was a very large impact. They estimate an object 10km in diameter, which left a crater 200km in diameter. They believe that material ejected during the impact actually reached suborbital altitudes and that much of the heat was generated by the friction of re-entry.
    Wouldn't that metemorph rocks as well?
    From the space.com article: "Previous work uncovered a global layer of material that had melted and then hardened when the impact vaporized terrestrial rock."
    Or even react the atmosphere?
    Not sure what you mean by that. They think the energy involved would have heated the atmosphere enough to cause widespread death, but that would require temperatures 100 degrees C.
  • by Anthony (4077) <adavid@adavid.com.au> on Thursday May 27, 2004 @07:30PM (#9272700) Homepage Journal

    Unfortunately the linked article is available in the Online Journal which you can either subscribe to or go to you neareast Uni Library and check it out.

    A Thermal heat pulse and the ejecta from the impact could travel around the world because of gravity dragging the ejecta back towards the earth. Upon reentry, the ejecta emitted IR radiation, brightening the sky globally. This means no night and no shadows (as the heat sources were distributed across the sky compared with the single-source solar IR radiation). This means there was nowhere to hide unless you were underground. Even rock crevices were no shelter. Subsequent fires igniting simultaenously [the suggest that there are isotopically uniform charcoal deposits at the boundary] would have added to the carnage. These fires were not significant compared to the intensity of the IR radiation. Normal solar flux ~1.4kW.m^-2, this event was calucated by Melosh in a previous paoer in 1990 to product ~10kW.m^-2. Note that ambient air temerature would have only rise ~10 K.

    As for survivors, those burrowers > 10cm below the soil surface would survive. Sheltering and semi-aquatic birds are posited to be survivors.

    The important thing is that this paper presents no specific fossil evidence. It does offer some phylogenetic evidence to support the bird survival hypothesis. It presents one model that can be further refined and/or refuted with evidence. It is not necessarily true or false but it can be falsified. They suggest checking Gondwanan sites for evidence of spherules (proof of ejecta reentering) and their distribution. That is the nature of science which the majority of posters thus far need to grasp. Think of science in terms of mathematical functions that approach a limit/converge as evidence and models accumulate.

  • Re:Broil? (Score:4, Informative)

    by barawn (25691) on Thursday May 27, 2004 @07:45PM (#9272817) Homepage
    Roast just means to cook in an oven. To broil something means to expose it to intense heat. It's the highest heat setting on an oven, and you're supposed to put the meat right beside the burners themselves.

    Hmm, considering there's a dish called "London Broil", it just makes me wonder if that's not actually British, but yet another American bastardization...
  • by Julian352 (108216) on Thursday May 27, 2004 @07:48PM (#9272849)
    To be more exact for your "a lot of energy" required to raise water over the air - it is about 4 times as much energy for water than air. That is because the specific head of fresh water is 1 (Ocean water is .93) while the specific heat of air is only .25. Thus it takes 4 times as much energy to raise 1g of water 1 degree Celcius as compared to a gram of air.

    This doesn't at all take into the account the fact that the starting temperature of the air is higher than that of the water. The average temperature of water in the oceans is just a bit above freezing in the pole areas and is about 17C(62F) on average (max 36C). The average temperature of air is much higher due to being over landmasses. Thus heating all of the air is MUCH easier than water.
  • by Anonymous Coward on Thursday May 27, 2004 @07:58PM (#9272939)
    You should look at this site for the megafauna the lived after the age of the dino's there were some huge animals. http://www.bbc.co.uk/beasts/factfiles/index_all.sh tml
  • by colonist (781404) on Thursday May 27, 2004 @08:06PM (#9273006) Journal
    Wired News is covering this topic too: A Fiery Death for Dinosaurs? [wired.com]
  • by Anonymous Coward on Thursday May 27, 2004 @08:14PM (#9273061)
    Also the density of air is much lower, so heating the same *volume* of water takes even more energy compared to air.
  • Re:Broil? (Score:2, Informative)

    by Impy the Impiuos Imp (442658) on Thursday May 27, 2004 @08:19PM (#9273095) Journal
    "Broil" is a special setting in electric ovens. It turns on a special set of burners at the top of the oven instead of the bottom. It's turns the oven into a giant super-toaster. You broil fish. You broil thin steaks. You can use the broiler to brown up just about anything at the end of the cooking.

  • by 1010011010 (53039) on Thursday May 27, 2004 @08:25PM (#9273138) Homepage
    Check out the Hydroplate Theory [creationscience.com] -- a great SciFi movie, just waiting to be made! Or, at least, one better than "The Core."

  • by antimatt (782015) <xdivide0.gmail@ORG.NET.EDU.com> on Thursday May 27, 2004 @08:36PM (#9273211) Homepage
    the above reply dealing with specific heat is correct; another factor, though, is the extreme difference in density between water and air. one gram of seawater takes up about 1 cm^3; one gram of air at sea level takes up about 800 cm^3. so for some given amount of heat, we can raise the temperature of 1 cc of seawater, or we can heat 3200 cc (800 x 4, where 4 is the specific heat factor of water/air) of air the same temperature.

    having huge oceans is really why we can exist without dying. they act as a massive heatsink that stabilizes the temperature of the rest of the planet, keeping the days from cooking us and the nights from freezing us. ... ever wonder why desert climates vary so much from night to day? no water in the air.
  • by br0d (765028) on Thursday May 27, 2004 @08:47PM (#9273290) Homepage
    Randomly surfing around for data on chicxulub crater the other day, and I came across this neat little extinction animation:

    http://sushi-x.com/gallery/4d/chicxulub.zip

  • Re:Survival (Score:2, Informative)

    by Xyrus (755017) on Thursday May 27, 2004 @09:33PM (#9273576) Journal
    You underestimate by quite a bit.

    Survival? Realize the magnitude of an impact that could produce a crater that size.

    Massive global earthquakes, volcanic eruptions, a shock wave many times the speed of sound and essentially a wall of fire incinerating everything in it's path for many miles, absolute disruption of global weather patterns, fallout, etc... etc...

    Use one of the asteroid simulators. Even if you were on the other side of the planet you'd get 10+ magnitude earthquake along with a hefty shockwave more than strong enough to rip apart any remaining structures still standing. I'm not talking about crumbling. I'm talking about steel girders being smashed into splinters.

    We could unleash all nuclear weapons at the same time in one spot and we wouldn't even get close to the energy an impact like this would unleash.

    No, an impact like that would pretty much scour the surface of the planet. Maybe through sheer luck some very small number of humans would survive. They would be the unlucky ones, as there would be nothing left.

    Life would survive and evolve out of this as it always does, but humans would become extinct along with a large number of other life forms.

  • by jtev (133871) on Thursday May 27, 2004 @09:39PM (#9273619) Journal
    Of course it shouldn't be accepted just because there is no disproof, there has to be evidence of the theory for it to be accepted. No theory can ever be proven. This is acutaly a central tennant of Science. You can have tons and tons of supporting evidence but you NEVER prove your theory. Also a single counter instance disproves a theory. The thing about evolution is that there is considerable evidence supporting the theory. From the finches on the galapgos islands, to the fossil record, to the way that selective breeding has worked for millions of years. Now, if you can provide me with counder evidence to these phenomonon, I'll be more than happy to say Darwin was wrong, after all, he's just a British stiff, what does he know.
  • by mr_z_beeblebrox (591077) on Thursday May 27, 2004 @09:41PM (#9273629) Journal
    Evolution can never be proven by science. And that goes for the entire array of evolutionary theories.

    Domestication is a form of evolution. By man learning and practicing husbandry of animals and selecting desirable traits he (he in the generic sense) exerted specific pressures on large based familial lines. Thus was eventually born our concept of breeds. The blue heeler was bred for herding ability, the greyhound for running, the poodle as a dare (?). nearly every trait that a modern dog has is genetically coded in his ancestor the wolf it is only the frequency of expression which sets them apart. That information is part of the reason that the smithsonian (who is responsible for taxonomy) reclassified the dog from C. familiaris to C. lupus familiaris.
  • by ynotds (318243) on Friday May 28, 2004 @12:25AM (#9274483) Homepage Journal
    Bacteria exchange genetic material.

    Viruses mediate the exchange of genetic material.

    The development pathway that unites all animals includes a stage in which a viable (usually fertilised) egg cell (zygote) divides a number of times to form a ball of cells (morula, blastula) gradually differentiating because of (dorsal/ventral etc.) gradients in (HOX) gene expression.

    Sponges (porifera) are a likely candidate for the oldest surviving animal lineage, potentially dating from the recently annointed Ediacaran Epoch [slashdot.org] through the Cambrian explosion, so called because the basic developmental forms of animals diversified wildly in a (geologically) short time.

    Hermaphroditic sponges produce sperm and eggs [berkeley.edu] at different times, obviating themselves, and thus the last common ancestor of all sexually reproducing animals, from any requirement for different male and female phenotypes.

    Sexual dimorphism came later and very differently in different taxa.

    Such "all or nothing" questions are a standard intellectual trap for people who cannot see the overwhelming evidence for the fact of evolution, a fact that various theories strive to account for without ever needing to overturn the core Darwinian insight that everything alive today is the product of a very long history of variation and selection from multitudinous common ancestors.

  • Because, cladistically speaking at least, birds are dinosaurs, most closely related to the Dromaeosauridae like the Velociraptor.

    True - but the dinosaur ancestors of birds displayed none of the attributes that this paper specifies as enabling them to escape this instant extinction story. So that hurts rather than helps their case.

    Mammals 65 million years ago were tiny (mice sized) and most likely nocturnal

    There were larger [abc.net.au] ones.

    And this leaves out all the animals that survived and were much larger than many of the dinosaurs that went extinct. Crocodiles, for example. They weren't small, and couldn't burrow - so this bit of speculation falls straight over.

    Then, of course, there's all the animals that lived in the sea that died out right along side similar-sized animals that didn't.

    No, I think simplistic explanations just aren't going to cut it. Clearly there was something more complex going on - but it's unlikely we'll ever know for sure at this point, short of inventing a time machine. Certainly the fact that population sizes and diversification had already been decreasing for quite a long time tell us that there were other factors at work.
  • by Blastrogath (579992) on Friday May 28, 2004 @01:04AM (#9274680)
    Larger animals are usually the first to go when there's a disaster or climate/habitat change.

    Large carnivores need large prey. See next paragraph.

    Large herbivores need large vegitation. An impact like this would also create an ice age, even a large volcano can effect the climate for years. The heat pulse then climate change would kill off most of the large vegitation.
  • by TowelPlease (783611) on Friday May 28, 2004 @02:06AM (#9274883)
    In terms of evolution, sexual reproduction as compared to asexual reproduction is 'worse', it is less effecient and more time-consuming. So their must be a pay-off: Parasitism is one of the main selection pressures on many animals, so most animals have a very good defence against them, and so parasites in turn evolve rapdidly to overcome their hosts defences. Offspring are likely to be in an enviroment where they are parasitised by organisms well adapted to parasitising their parents. So producing offspring with with a higher genetic variability and therefore less like their parents is beneficial. Sexual reproduction does this. An example is aquatic snails, asexual females are common in an enviroment with relatively few trematode parasites, both males and females are common in enviroments with lots of them.
  • by sql*kitten (1359) * on Friday May 28, 2004 @04:10AM (#9275257)
    You mean to tell me that Brits don't use the word "broil"?

    What you call broiling we call grilling. What you call grilling we call frying. What you call frying we call deep frying.
  • Re:Broil? (Score:3, Informative)

    by aziraphale (96251) on Friday May 28, 2004 @05:10AM (#9275419)
    US 'grilling' seems to have two meanings - there's the George Foreman sense - which we Brits would tend to call 'griddling'; and there's the outdoor sense, which in britain we call 'barbecuing'. Occasionaly, British people will use phrases like 'cooked over a grill', or 'flame grilled', to describe grilling in the American sense.

    When we say grill, we mean what you call broiling.
  • Re:Broil? (Score:1, Informative)

    by Anonymous Coward on Friday May 28, 2004 @06:42AM (#9275736)
    Roast just means to cook in an oven.

    No, roasting is cooking in an oven in fat. If there's no fat, you're baking, not roasting.

    At least, that's how it is in Britain... doubtless you Americans use the names the other way round or something.
  • Grill (Score:3, Informative)

    by tiled_rainbows (686195) on Friday May 28, 2004 @07:02AM (#9275810) Homepage Journal
    The British Word is "Grill". It can be a verb "To grill a lamb chop", or a noun "Puty that chop under the grill".

    Regarding London Broil, I've seen tins of stuff called "London Grill" which appears to be beans and bacon bits and sausages and black pudding and bits of kidney all mixed together in tomato sauce. Which sounds pretty grim, but grim in a particularly English way.
  • by Alsee (515537) on Friday May 28, 2004 @07:40AM (#9275918) Homepage
    Is the metor that hit the earth and killed off the dinosaurs in any way to the breakup of pangea?

    Nope, the the pangea breakup was around 150 million years earlier. A guesstimate off by a factor of 3 or so ain't so bad when your talking about geological timescales :)

    Here's a rough map of the Earth 65 million years ago. [kaibab.org]

    -
  • by Oligonicella (659917) on Friday May 28, 2004 @08:50AM (#9276246)
    Today one of the largest "land" animals spends a lot of time in the water, the hippo. The rest don't (elephant, rhino, buffalo, giraffe).

    Apatosaurus (not a new name at all) tracks have been found on definitely non-swampy terrains in numbers indicating herds. Also, their nests were not in swamps.

    You really need to read more.
  • by ianscot (591483) on Friday May 28, 2004 @09:44AM (#9276589)
    We don't have to imagine exotic dinosaur muscle properties being involved to see animals considerably bigger than elephants.

    Indricotheres [yahoo.com] were considerably bigger than elephants -- around twice the mass. They're mammals, the closest living relations being rhinos. Dinosaur-sized mammals, easily. Think giraffe height with the mass of a rhino.

  • by Moraelin (679338) on Friday May 28, 2004 @10:39AM (#9277051) Journal
    Actually, there are perfectly good biometric simulations that show that, at the exact same muscular efficiency as today's animal muscles, dinosaurs could jolly well exist and move.

    The catch: they were most likely very slow. E.g., assuming a reasonable distribution of its muscles (and not, say, 90% of the body weight concentrated into the leg muscles), you could easily outrun a Tiranosaurus Rex.

    That was one of the faster dinosaurs for its size, btw. A herbivore was a lot slower. It only had to walk very slowly from tree to tree.

    Standing up is not just a questions of muscles, it's also one of bones. Try just standing up without moving. You don't have to work your muscles too hard to do that, do you? In fact you could be almost completely relaxed and still remain standing. Most of the weight is supported by the bones, not the muscles.

    Even with the disparity in the exponent between muscle force and body weight, you could probably be 10 times taller and still have no problems.

    For a four legged animal -- such as all the largest dinosaurs -- it's even easier. For that kind of animal, you don't have to use the muscles to keep the back straight. It's basically a suspended bridge between the hind legs and the fore legs.

    I.e., to just stand at that size, the dinosaurs mostly needed good bones. Which they had. The larger dinosaurs had _massive_ bones to support their weight.

    Now walking or running is another exercise. Then you actually have to move that mass around. For that you need muscles.

    Fortunately, up to a point you can get away with just moving slower. You _can_ design an animal much larger than an elephant, but the catch is that it will run much slower than an elephant.

    Which again, is what the dinosaurs most likely did.
  • by Alsee (515537) on Friday May 28, 2004 @03:01PM (#9279723) Homepage
    Modern elephants are known to have hit 12 tons. If you were to naively double the height, width, and length of an elephant that's 96 tons right there.

    Can you possibly double the muscle/bone stresses on an elephant like that? Circus elephants have been trained to go from a sitting position to standing on just their rear legs (front legs in the air through the whole process). So it is clearly within the stregth limits of ordinary muscle and bone to double the load (and thus scale) in an ordinary elephant.

    Of course nature does NOT use naive designs. If you were to double the scale of an elephant (and 8 times the mass) over tens of millions of years, evolution leads to redesign and major optimizations. An animal 8 times the mass does not need need 8 times as much skin mass or brain matter or heart or liver or kidneys etc etc etc. Such an animal could easily have 10 or 11 times as much raw bone and muscle muscle mass. Bone density can increase. Structure can change. Manuverability/strength/safety margins in some areas can be traded off for bone and muscle mass in other areas. For example there are also signifigant advantages to be had by sacrificing abilities such as running - and even elephants can run. Such redesign may increase kneww and other joint leverage by a factor of 2 or so. With such optimizations it is certainly possible to more than double the scale of an elephant.

    And while raw strength of muscle and bone suffer from square-cube issues, it turns out that stamina / work / power for walking around actually improves with increasing scale.

    If you were to naively stretch a human neck to many feet in length it would instantly snap. Obviously with evolutionary redesign giraffes have no trouble with necks many feet long. It is also "impossible" for any mammal to pump blood to the altitude of a giraffe brain - or at least it seems obviously and mathematically imposible until you look at the specific structure redesigns in a giraffe. When you redesign a structure the limits fundamentally change.

    P.S.
    About your sig and Metanet. While I support the idea, there are just way too many security flaws. For example it would fail to a blind traffic analysis attack and it ingores the fact than an attacker can set up an arbitrarily large chain of nodes under his own control. Arbitrary trusted nodes may fall under attacker control through related or even unrelated leagal action. There is also an international treaty floating around to deal with exactly that sort of situation. I can also think of a few more sophisticated attacks. It's really tough to get a solid level of security.

    -

Going the speed of light is bad for your age.

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