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Dinosaurs Died Within Hours of Asteroid Impact, says New Study
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.'"
An appropriate post for the Memorial Day weekend. Imagine the world's largest barbeque.
the major advances in civilization are processes which all but wreck the societies in which they occur - A.N. White
For us ignorant Brits, wthat's that in Gas Mark?
Stick Men
I'd like to RTFA, I really would !
it's too bad their all-star oil drilling team didn't quite make it in time...
At least the dinosaurs went out baked!
----
Go canucks, habs, and sens!
The real reason dinosaurs became extinct!
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
"Studies have shown that people who eat peanuts live longer than those who do not eat."
Alright, so what do I need to survive the next major asteroid impact of this magnatude? It sounds like most buildings won't be sufficient protection.
Do I need a cave to hide in? Should I go to a large body of water?
The Emeril Lagassaurus Rex would have added some prehistoric garlic when he saw the meteor coming...then BAM!!!! Another notch!
"Hey, Lou, what the F is " *SPLAT*
Everything in science is a theory. The "asteroid impact" idea has a lot to back it up however since there are some realy big craters on this ball of mud we call home. Check out the 170 km one at the Yucatan Peninsula.
"Have you ever thought about just turning off the TV, sitting down with your kids, and hitting them?"
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
Gas Mark is a Fahrenheit scale.
From this chart 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.
Stick Men
Taken from: Wikipedia article on theory:
So, proven for 99.9999% theory of gravity is still a theory.
When in doubt, go to the library. - Ron Weasley in Harry Potter and the Chamber of Secrets
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
My Sig Beat up your Honor Roll Sig
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?
Why don't you guys have friends or journals?
The majority of the dinosaurs were instantly fried, like in a nuke blast that wrapped around the globe. I haven't seen a movie lately, that had those kind of cool FX. How about you?
Think about to all the meteor's crashing into earth movies there are, now think about all the FX. Nothing as impressive as ALL THE DINOSAURS getting fried as a heat wave travelled around the globe.
Why can't Hollywood just pay attention to history and science. It's way cooler than the drek they come up with.
But seriously folks, just think of all the Brontoburgers. I bet Fred and Barney boiled off the surface still salivating at the endless plains of dino ribs.
Arrogance is Confidence which lacks integrity. -- me
So many things survived from that time other than the Dinosaurs. Large trees, many forms of reptiles and mammals that are virtually the same (based on fossil records) to this day.
Not too mention that the fossil records for Dinosaurs don't stop on 1 day.
It seems that the Doomsday theory gets more headlines than other theories suggesting, disease and climate change (a much slower, more boring process) were the cause. Even though the damage of a meteor strike would have been far more devastating and left the planet set back near square one as far as life.
If the earth was baked and then the sun was blocked by smoke and ash, how come so much survived?
*Note IANAS (I Am Not A Scientist), just wondering.
http://www.kubuntu.org/
"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 has some more information along with Wikipedia.
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.
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.
The correlation between ignorance of statistics and using "correlation is not causation" as an argument is close to 1.
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.
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.
I think we can now all breathe a huge sigh of relief as we know the dinosaurs did not, I repeat, did NOT suffer. We will all gain a few hours of sleep a night, I'm sure.
All unprotected creatures were 'baked by the equivalent of a global oven set on broil.'"
Thanks for the metaphor. This "heated air" concept is difficult to get across to the layperson.
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.
This is my sig. There are many like it but this one is mine.
Personally, I'd like for these theories to go through a bit more critical review before they're broadcast to the public. This smacks as sensationalism more than science.
Am I part of the core demographic for Swedish Fish?
Zubenelgenubi is a double star. Which one do you mean? Assuming you're talking about the hotter one, Alpha-2, that'd be about 583.
There is a theory that the earth was lighter back then, which let heavier animals thrive. It's an interesting theory - it also says that the Pangea continent covered the whole earth (not just one side) since the earth was ~40% of it's current size, and that it grew by collecting space debris over time. Someone should do the math concerning muscle efficiency and this ancient mass of the earth and see if it works out.
-- This sentence is false.
So now we have prior art for animal crackers.
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.
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...
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.
The correlation between ignorance of statistics and using "correlation is not causation" as an argument is close to 1.
Well accepted doesn't make it correct. It's still a theory, and one (I might add) that cannot be proven, unlike a few others you've quoted.
Unlike in some circles, well accepted means no has yet found evidence against it in science. Not, we all beleive it to be true. When someone has evidence against it, it becoem a disproved theory is the evidence is strong enough. However the theory of evolution has had no credible evidence against it, neither has gravity, or thermodynamics. Only small addendums.
I have faith in Christ. I need not refute scientific evidence to support my faith. God is wonderfull, sometime msyterious, and I needn't beleive in fairies ot beleive in God. Why should I beleive in creationist theories when the evolution theory fits my faith just fine.
"There are more things in heaven and earth, Horatio, than are dreamt of in your philosophy."
I read the article
Another wild hypothesis without a shred of verifyable evidence.
I couldn't read it THIS time (because the server is slashdotted). But I did read it - or another describing the same theory - when it first became newsworthy some years ago.
There's plenty of evidence for it.
First off, the prediction comes straight out of physical modeling of what happens when a big asteroid hits:
- A bunch of rocks are kicked every which way.
- If the asteroid is big enough a LOT of them go into space.
- A fraction of them have enough energy to get above the atmosphere but not achieve escape velocity.
Once you realize those three things, it's straightforward for a physicist to calculate, for various size impacts on various sites (land, shallow ocean, deep ocean), how MUCH mass goes up, how MUCH of it comes back down, WHERE it comes down, HOW FAST it comes down, and what the results are.
So they calculated that. And came to the conclusion that for impacts of a certain range of sizes the result would be several hours of a rain of sand, all over the Earth, at speeds of up to several miles per second (plus rains of rocks of varying density at different distances from the crater and its antipode). The sky becomes essentially solid meteor trails for hours.
And those are HOT! Hot enough to dry out most of the plants and set them afire. Hot enough to kill any animal life on the surface that can't get underground or under water right away and then stay there for hours.
So if the sky turned into a broiler oven over the whole Earth for several hours all at once, what does this predict? One hemisphere is day and the burrowing nocturnals survive, the other is night and the burrowing diurnals survive. (And in particular regions it got REALLY hot, or REALLY shocked by the primary impact or the secondary rain of rocks, and NOTHING survived).
So they looked at the fossil record and that's what they found. Prediction confirmed - very good evidence for the model. Further, they could now tell WHAT TIME OF DAY the impact occurred and roughly where.
Then they looked in the area where this model predicted the impact should have been and FOUND A CRATER of the correct size (along with plenty of other evidence that this PARTICULAR crater's impact coincided with the extinction event).
Looks solid to me. Unless something new comes up I consider the puzzle of the extinction events solved.
The only question I have is: Why is this news NOW?
Bantam Dominique roosters crow a four-note song. Once you've heard it as "Happy BIRTHday" you can't NOT hear it that way
But the fact is, that land animals larger than elephants have, in fact, existed. Mass does indeed go up as a cube of length, but land animals (dinosaurs included) aren't just cubes of flesh and bone. If you take the large amount of non-solid space in the lungs and gastro-intestinal system, you do reduce the density, and therefore the mass by an extent.
There is quite a bit of research going on in this area that relates to dinosaurs. I don't have any specific refs, but if you check out the recent literature, you should be able to find a number of current articles.
'Loose' is when your pants are three sizes too big. 'Lose' is when you misuse 'loose'.
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.
Slashdot: Where nerds gather to pool their ignorance
> 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).
Wow, how old ARE you?
Before you design for reuse, make sure to design it for use.
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.
When doing comparisons be careful to avoid human muscle. Humans are cursorial hunters (jogging after their prey until it collapses from heat exhaustion.) Most of their muscles are set up to only use a few percent of their fibers at a time - and switch to another batch when the first run out.
That's why hysterical strength is so much greater: Under great stress you CAN use your whole muscle power for a few contractions - like a mother lifting a car off her kid (a rather common event, actually). But it comes at a cost: The bones, pads between them, and muscle attachments are NOT built to the necessary strength for this. Use of hysterical strength normally means some serious, often permanent, injury.
Most other animals (including even our close relatives the chimps) use a much higher fraction of their muscles all the time - or under only moderate provocation - and have the structure to support this use. (That's why they're so dangerous to people who handle them without having armor on and weapons handy.)
Land animals probably can't be much bigger than an elephant.
Not if they're going to be chased around by lion prides, packs of canids, and humans. (The square-cube law also applys to dumping heat.) You can build a workable animal MUCH bigger than an elephant. But now that there are warmbloods specializing in running things to collapse and eating them you can't keep a population of things that large viable in the wild.
Bantam Dominique roosters crow a four-note song. Once you've heard it as "Happy BIRTHday" you can't NOT hear it that way
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.
According to the abstract fires would have begun wherever there was available fuel. Wouldn't there be a world-wide charcoal layer to go along with the Iridium layer if that were true?
Obviously, the dinosaurs were ignorant of the "Duck And Cover" method for surviving an incinerating holocaust. Or is that only for nukes?