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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.'"
Broil is when you put the food directly under the flames.
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
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
"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.
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.
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.
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
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...
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.
Also the density of air is much lower, so heating the same *volume* of water takes even more energy compared to air.
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.