Skip to comments.It's Official: An Asteroid Wiped Out the Dinosaurs
Posted on 03/05/2010 5:46:05 AM PST by jilliane
A giant asteroid smashing into Earth is the only plausible explanation for the extinction of the dinosaurs, a global scientific team said on Thursday, hoping to settle a row that has divided experts for decades.
(Excerpt) Read more at news.yahoo.com ...
“It’s the only plausible explanation” is NOT science
So they have ruled out gamma ray bursts, the effects of a weakened magnetic field, and the eruption of a supervolcano?
... aren't you forgetting someone???
Hey! It’s a consensus. Jump on board.
Yeah, just like it’s official that CO2 emissions are causing “global warming”. This is BS. It’s far from ‘official’. It very likely was a combination of factors.
I think they formed a nanny state and banned themselves to death.
How about tazered by the Mother Wheel???
SCOFF! Those things were not even considered! This is settled science, my boy!
True, but the hypothesis is every bit as valid as the one put forth by the Warming nuts and maybe more so because they don't seem to be trying to manipulate or hide data.
Non-beleivers will be hunted down and burned at the stake, using a smoke reclamation system, of course.
You are an idiot. It damn well is science. You want to challenge it you can. Just put forward another hypothesis and show that it is a better explanatory fit for the data than the preferred hypothesis. THAT is science, you nattering nabob of cluelessness. What is not science is folks like you sitting on the sidelines and jeering in favor of the powers of darkness and ignorance.
And just for those clueless twits who don't f'in get it. The catastrophic asteroid theory of dinosaur extinction was first put forward by a team of physicists and geophysicists including the great Luis Alvarez. They did incredibly careful work to find new data (including the observation of a layer of iridium, etc.) that lead to the formation of this hypothesis and its general acceptance. This is not global warming. It is based on the most careful science the best scientists in the world knew how to do. It is way way way over your pea brained comprehension.
There is a political point behind this highly personal attack. It is my belief that conservatism is the direct product of the enlightenment through our founding luminaries. It is not the product of ignorance, prejudice and idiocy, like you have expressed. There is no room in MY branch of conservatism for anti-scientific idiots because your kind of attitude leads people to revile conservatives and leads to the election of what we presently have.
I still haven’t figured out how wooly mammoths were frozen with food in their mouths...
Actually, if you had paid attention, they were. They just don't fit the data is the problem.
Until recently most scientists thought they knew what killed off the dinosaurs. A 10km-wide meteorite had smashed into the Yucatan peninsula in Mexico, causing worldwide forest fires, tsunamis several kilometres high, and an 'impact winter' - in which dust blocked out the sun for months or years. It was thought that the dinosaurs were blasted, roasted and frozen to death, in that order.
But now a small but vociferous group of scientists believes there is increasing evidence that this 'impact' theory could be wrong. That suggestion has generated one of the bitterest scientific rows of recent times.
The impact theory
For supporters of the impact theory, the KT boundary layers contained two crucial clues. In 1979 scientists discovered that there were high concentrations of a rare element called iridium, which they thought could only have come from an asteroid. Right underneath the iridium was a layer of 'spherules', tiny balls of rock which seemed to have been condensed from rock which had been vapourised by a massive impact.
On the basis of the spherules and a range of other evidence, Dr Alan Hildebrand of the University of Calgary deduced that the impact must have happened in the Yucatan peninsula, at the site of a crater known as Chicxulub. Chemical analysis later confirmed that the spherules had indeed come from rocks within the crater.
The impact theory seemed to provide the complete answer. In many locations around the world, the iridium layer (evidence of an asteroid impact) sits right on top of the spherule layer (evidence that the impact was at Chicxulub). So Hildebrand and other supporters of the impact theory argued that there was one massive impact 65 million years ago, and that it was at Chicxulub. This, they concluded, must have finished off the dinosaurs by a variety of mechanisms.
Challenging the theory
They concentrated on a series of rock formations in Mexico where the iridium layer was separated from the spherule layer by many metres of sandstone. That opinion sparked a massive row, as the supporters of the impact theory such as Prof Jan Smit of Vrije Universiteit, Amsterdam, rubbished Keller's ideas. Smit argued that the sandstone had been deposited by massive tsunami waves caused by the asteroid, and so did not undermine the idea of a single impact.
But Keller's team found evidence - such as ancient worm burrows - that suggested that the deposition of the sandstone had been interrupted many times. They concluded that there was a gap of some 300,000 years between the deposition of the spherules (from the Chicxulub crater) and the iridium (from an asteroid). Therefore there must have been two impacts.
The Chicxulub impact, they said, was too old to have finished off the dinosaurs, and there must have been another impact somewhere else which was to blame. That crater has not yet been found.
Although still in the minority, Keller's work does now attract some support. And a range of scientists have begun to question other hypotheses connected with the impact theory. Claire Belcher of Royal Holloway, University of London, has found evidence which suggests that wildfires were not widespread in North America following the KT impact.
Prof Dave Archibald of San Diego State University is convinced that the survival of creatures such as frogs disproves the idea that the dinosaurs perished amid acid rain as strong as battery acid, or that an 'impact winter' caused a massive and sustained drop in temperature.
Dr Norman MacLeod of the Natural History Museum in London is among a large group of scientists who are convinced the dinosaurs were already being driven to extinction by climate change long before the arrival of the KT impact, or impacts.
It is like my favorite, the hypothesis that Shakespeare could not have been Shakespeare because no one was smart enough to write what Shakespeare wrote. So, the only way to explain the existence of one extraordinary and highly improbable genius is to hypothesize either a.) that it was really some other extraordinary and highly improbable genius, or b.) that it was really two extraordinary and highly improbable geniuses (like betting to draw an inside straight not once, but twice).
This is not science. It is conjecture and speculation. It is a theory. It is unproven and cannot be duplicated in a lab. get a clue. It isn’t like what passes for science these days is a perfected science, is it?
How many articles have you read lately that the beginning of the second paragraph says science must now rethink what they have thought...or scientists were shocked and amazed...or that there could not possibly be water on the moon...or....
I haven’t yet taken the “Mother Wheel” course at the University of Discovery Channel!
But I have discovered a lot of ways to go extinct that I never had to worry about before..:-(
interesting stuff, but these guys should just give it up
now that impact extinction is “settled science”
Disclaimer: Opinions posted on Free Republic are those of the individual posters and do not necessarily represent the opinion of Free Republic or its management. All materials posted herein are protected by copyright law and the exemption for fair use of copyrighted works.