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Show ALL Forums  > Science/philosophy  > It's official: An asteroid wiped out the dinosaurs?      Home login  
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 SteelCity1981
Joined: 8/16/2005
Msg: 1
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It's official: An asteroid wiped out the dinosaurs?Page 1 of 7    (1, 2, 3, 4, 5, 6, 7)

LONDON (Reuters) – 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.

A panel of 41 scientists from across the world reviewed 20 years' worth of research to try to confirm the cause of the so-called Cretaceous-Tertiary (KT) extinction, which created a "hellish environment" around 65 million years ago and wiped out more than half of all species on the planet.

Scientific opinion was split over whether the extinction was caused by an asteroid or by volcanic activity in the Deccan Traps in what is now India, where there were a series of super volcanic eruptions that lasted around 1.5 million years.

The new study, conducted by scientists from Europe, the United States, Mexico, Canada and Japan and published in the journal Science, found that a 15-kilometre (9 miles) wide asteroid slamming into Earth at Chicxulub in what is now Mexico was the culprit.

"We now have great confidence that an asteroid was the cause of the KT extinction. This triggered large-scale fires, earthquakes measuring more than 10 on the Richter scale, and continental landslides, which created tsunamis," said Joanna Morgan of Imperial College London, a co-author of the review.

The asteroid is thought to have hit Earth with a force a billion times more powerful than the atomic bomb at Hiroshima.

Morgan said the "final nail in the coffin for the dinosaurs" came when blasted material flew into the atmosphere, shrouding the planet in darkness, causing a global winter and "killing off many species that couldn't adapt to this hellish environment."

Scientists working on the study analyzed the work of paleontologists, geochemists, climate modelers, geophysicists and sedimentologists who have been collecting evidence about the KT extinction over the last 20 years.

Geological records show the event that triggered the dinosaurs' demise rapidly destroyed marine and land ecosystems, they said, and the asteroid hit "is the only plausible explanation for this."

Peter Schulte of the University of Erlangen in Germany, a lead author on the study, said fossil records clearly show a mass extinction about 65.5 million years ago -- a time now known as the K-Pg boundary.

Despite evidence of active volcanism in India, marine and land ecosystems only showed minor changes in the 500,000 years before the K-Pg boundary, suggesting the extinction did not come earlier and was not prompted by eruptions.

The Deccan volcano theory is also thrown into doubt by models of atmospheric chemistry, the team said, which show the asteroid impact would have released much larger amounts of sulphur, dust and soot in a much shorter time than the volcanic eruptions could have, causing extreme darkening and cooling.

Gareth Collins, another co-author from Imperial College, said the asteroid impact created a "hellish day" that signaled the end of the 160-million-year reign of the dinosaurs, but also turned out to be a great day for mammals.

"The KT extinction was a pivotal moment in Earth's history, which ultimately paved the way for humans to become the dominant species on Earth," he wrote in a commentary on the study.

(Collins has created a website at http://impact.ese.ic.ac.uk/ImpactEffects/Chicxulub.html which allows readers to see the effects of the asteroid impact.)

http://news.yahoo.com/s/nm/20100304/sc_nm/us_dinosaurs_asteroid


So do you agree or should scientists still do more research?
 stargazer1000
Joined: 1/16/2008
Msg: 2
It's official: An asteroid wiped out the dinosaurs?
Posted: 3/5/2010 8:06:47 PM
The evidence seems reasonably solid. Unless something else comes along...
 RocketMan_Len
Joined: 7/5/2006
Msg: 3
It's official: An asteroid wiped out the dinosaurs?
Posted: 3/5/2010 9:20:44 PM
Personally, I think that it was likely to be a combination of all these things that led to the mass extinctions of the Cretaceous.

A sizable asteroid impact would have caused the Earth to 'ring' like a gong - seismic waves would have rippled around to the antipode of the event... possibly triggering the Deccan eruptions.

Much like the theories coming together about the Permian extinctions - the Siberian eruptions dumped CO2 into the air, causing a warming trend. This warming triggered the release of methane from the ocean floor, as the water warmed enough to melt the methane hydrate deposits. This led to an accelerated warming trend, which very few species could adapt to quickly enough.

I imagine something similar could account for the K/T extinction - not a single event, but a series of them... like dominoes, one disaster initiates another, until catastrophe happens.

It always irritates, when people get into this 'either/or' debating style - it may not have had to be one or the other... it might have been ALL of them.
 U make it entertaining
Joined: 7/17/2009
Msg: 4
It's official: An asteroid wiped out the dinosaurs?
Posted: 3/6/2010 6:12:14 AM
Makes sense to me. We will never know the true answer, however this one does answer a lot of questions.
 Jiperly
Joined: 8/30/2006
Msg: 5
It's official: An asteroid wiped out the dinosaurs?
Posted: 3/6/2010 6:36:40 AM
Something about this feels vaguely "Scientists all around the world agree that Global Warming exists".....

I mean, from what little information of dinosaurs I've had, I agree they were killed by an astroid(and I grew up knowing about the impact in Mexico that was the most likely culprit)- although I suspect some of the smaller ones over time evolved into birds, since their skeletons seem to have such striking simularities....

....But I just don't like the idea of a group of scientists standing up and saying "We're right, any disagreement is moot and should shut up, because this is how it is"- I don't like it with the global warming crowd, and I don't like it here. As far as I can tell, these scientists don't bring any new facts to the table- they're just a committee thats convinced themselves that they are right.
 endlesslift
Joined: 12/31/2009
Msg: 6
It's official: An asteroid wiped out the dinosaurs?
Posted: 3/6/2010 7:18:44 AM
I agree and think that scientists should still research it.
 stargazer1000
Joined: 1/16/2008
Msg: 7
It's official: An asteroid wiped out the dinosaurs?
Posted: 3/6/2010 7:28:54 AM
I agree and think that scientists should still research it.


They do. And will. Remember, the K-T event is only one such event in Earth's history. So, while a panel of scientists might say the evidence is conclusive, there's still going to be scientists who don't agree or, at the very least, don't view it as the final story.

There is some indication that species diversity was actually on the decline prior to the K-T event. However, the Chicxulub crater is a fact. The K-T boundary is a fact. The total disappearance of large dinosaurs past the K-T boundary is a fact.

These facts lead to one reasonable conclusion.
 aremeself
Joined: 12/31/2008
Msg: 8
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It's official: An asteroid wiped out the dinosaurs?
Posted: 3/6/2010 12:12:38 PM
cost a lot of money, but ok. [the past and continued study with no real tangible reasons]

remember seeing the guy pull the knife out of the corpse?
well, he didn't stick it in, even though it really looked like he did it.
 yna6
Joined: 1/21/2007
Msg: 9
It's official: An asteroid wiped out the dinosaurs?
Posted: 3/7/2010 7:48:16 AM
I was taught this crap 40 years ago in public school...about time the scientific community caught up!

Ok....they are actually just saying "we feel this is what most likely happened, there, it is..." so what? The obvious becomes apparent after 40+ years?
 CallmeKen
Joined: 9/4/2009
Msg: 10
It's official: An asteroid wiped out the dinosaurs?
Posted: 3/7/2010 8:18:00 AM

cost a lot of money, but ok.


No, not ok. The US is $12 trillion in debt and growing daily. Millions of people are losing their homes to foreclosure, whole families are in homeless shelters and 1 out 8 Americans are having problems facing hunger. If the dinosaurs died by meteor, or were all sneezed off the Earth by the Great Green Arklesneezure, will it really change anything?

If Disney or General Mills wants to fund the research, hey, it's the company's dime. If the stockholders want their money spent that way, go for it. But taxpayer dollars? There are multitudes of priorities more important than what killed a bunch of lizards.
 aremeself
Joined: 12/31/2008
Msg: 11
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It's official: An asteroid wiped out the dinosaurs?
Posted: 3/7/2010 10:43:11 AM
callmeken

and yes, do governments ever waste your money!
and yes, what for?

moon
mars
and a few other expensive distractions
 emptinestr
Joined: 11/8/2008
Msg: 12
amphibians
Posted: 3/7/2010 12:58:23 PM
but...if I recall correctly, amphibians were also present on earth at this time. Why weren't they wiped out?
 Con Ten Ted
Joined: 6/25/2009
Msg: 13
It's official: An asteroid wiped out the dinosaurs?
Posted: 3/8/2010 3:49:17 AM
. . . . . . . is this the final answer ..... or are they ( the Scientists) saying " for now, this is the best fitting answer ....". Was this event also responsible for the "wobble" in the Earths spin ...... anyone Know ???
 stargazer1000
Joined: 1/16/2008
Msg: 14
It's official: An asteroid wiped out the dinosaurs?
Posted: 3/8/2010 5:59:42 AM

is this the final answer ..... or are they ( the Scientists) saying " for now, this is the best fitting answer ....". Was this event also responsible for the "wobble" in the Earths spin ...... anyone Know ???


Essentially, all science is "the best fitting answer" unless it can be replaced by something that better fits. For instance, scientists know that Relativity works and Quantum Theory works and yet the two are mutually exclusive. Therefore, something else is likely happening. If they can figure that out, it could lead to a theory that supersedes both.

As for Earth's "wobble," it's a thing called precession. From what I understand, it's a gyroscopic effect that would be induced on all rotating and revolving (around the sun in case some smart ass goes "But they both mean the same") bodies in the solar system.


but...if I recall correctly, amphibians were also present on earth at this time. Why weren't they wiped out?


The subsequent "nuclear winter" would have been hardest on the largest and most mobile creatures of the eco-system. In fact, I believe the theory holds that anything with a body weight over 10 pounds would have been wiped out. Remember, the mammals that existed at the time were small and likely lived underground. They would have had ample food supply throught roots, tubers and underground insects. Some creatures would have had other survival strategies already in place.

Remember, an extinction event doesn't have to mean everything goes extinct. Those whose inherent qualities made them best able to survive and adapt the calamity would have survived and gone on to colonize the niches left empty.


iridium: is allegedly common on asteroids meteors & also earth core
shocked quartz takes a bit of doing ;) -but would be constrained to the area of an impact crate and subsequent fall out


The particular isotope of iridium in question is most common in asteroids and is found in a very thin layer of carbon at the K-T boundary. The carbon comes from wildfires that would have radiated outward from the point of impact and consumed an very large portion of the biosphere.

As for the shocked quartz, no it wouldn't be constrained to the area of the impact. In fact, the impact would have been energetic enough (imagine a mountain hitting Earth at several times the speed of a bullet) and you can imagine how far and wide the material would have been blasted.
 msquared
Joined: 8/31/2004
Msg: 15
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It's official: An asteroid wiped out the dinosaurs?
Posted: 3/8/2010 6:32:57 AM
It is still my belief that the dinosaurs went extinct because they watched a Uwe Boll movie.
 RocketMan_Len
Joined: 7/5/2006
Msg: 16
It's official: An asteroid wiped out the dinosaurs?
Posted: 3/8/2010 6:47:29 AM

and yes, do governments ever waste your money!
and yes, what for?

moon
mars
and a few other expensive distractions


Right - all useless... as opposed to wars, and bank bailouts, and building monuments to our political leaders...
 stargazer1000
Joined: 1/16/2008
Msg: 17
It's official: An asteroid wiped out the dinosaurs?
Posted: 3/8/2010 6:56:20 AM

It is still my belief that the dinosaurs went extinct because they watched a Uwe Boll movie.


Fortunately, your belief is not evidence.
 msquared
Joined: 8/31/2004
Msg: 18
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It's official: An asteroid wiped out the dinosaurs?
Posted: 3/8/2010 8:50:28 AM

Fortunately, your belief is not evidence.


Obviously, my previous statement was completely serious and absolutely not intended in jest. *nods*
 stargazer1000
Joined: 1/16/2008
Msg: 19
It's official: An asteroid wiped out the dinosaurs?
Posted: 3/8/2010 9:09:12 AM

Obviously, my previous statement was completely serious and absolutely not intended in jest. *nods*


Ah. The dangers of posting prior to one's morning cup of tea!
 LeCutter
Joined: 2/25/2009
Msg: 20
It's official: An asteroid wiped out the dinosaurs?
Posted: 3/8/2010 6:52:49 PM
How do we know it wasn't mass-suicide? Maybe there was a Jim Jones of the dino-world and they all drank the special kool-aid when they saw the asteroid plummeting to earth!

Heh, it's as plasuible. I mean the asteroid theory doesn't account for why other reptiles and mammals survived. It doesn't account for why gigantism went out of style - seeing as we had it into the last ice age.
 VoidDancer
Joined: 9/22/2009
Msg: 21
It's official: An asteroid wiped out the dinosaurs?
Posted: 3/10/2010 7:21:38 AM
Just some thoughts … There is more and more evidence surfacing that humans and dinosaurs lived at the same time. An example is the controversial Peru stones. There is also the find of human and dinosaur footprints in the same fossil. You can google all this stuff and take a look.

There are other indications of the possibility humans and dinosaurs lived at the same time. Like, Edgar Cayce, America’s greatest sleeping prophet and others who have stated similar things.

Hey! … even Shara Palin shortly after she was elected mayor, stated that dinosaurs and humans coexisted … :-) … lol … It came out of the mouth of a politician, so it must be true. Don’t you think?

Fortunately or unfortunately … when I look at all the earth’s life forms … I think it is fairly safe to say that humans have wiped out more species than all the other species combined.

Can we be so sure that humans didn’t wipe out the dinosaurs? … Personally I am not so sure.

EnJoy … Love and Peace
 himynameisSarah
Joined: 5/27/2009
Msg: 22
It's official: An asteroid wiped out the dinosaurs?
Posted: 3/10/2010 11:22:44 AM
I killed the dinosaurs you foolish earthlings...

j/k yes, I'm sure it was a meteor. But, no matter how much science tries to uncover the past, they will remain theories... think away people.

have we blown up that big asteroid that's headed this way yet? Supposed to be bigger than Texas...
 CallmeKen
Joined: 9/4/2009
Msg: 23
It's official: An asteroid wiped out the dinosaurs?
Posted: 3/15/2010 6:08:17 AM

It doesn't account for why gigantism went out of style


Gigantism didn't go out of style. Just ask any guy on POF about the size of his
 desertrhino
Joined: 11/30/2007
Msg: 24
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It's official: An asteroid wiped out the dinosaurs?
Posted: 3/16/2010 2:32:43 PM

There are only 5000 fragments of dinosaur bones known to exist.

Cite?
 desertrhino
Joined: 11/30/2007
Msg: 25
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It's official: An asteroid wiped out the dinosaurs?
Posted: 3/23/2010 5:45:40 AM
Still waiting on those cites, formula154...
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