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Asteroid Breakup May Have Doomed Dinosaurs
Centauri Dreams ^ | 9/5/07

Posted on 09/05/2007 11:55:02 AM PDT by LibWhacker

It’s a disaster scenario that Hollywood has picked up on (think Deep Impact). An incoming object menaces the Earth. Scientists try to destroy it with nuclear weapons, but the horrified populace soon discovers that the blast has simply broken the object into pieces, each with the potential to wreak havoc planet-wide. Now we learn that an impact between two asteroids causing a similar crack-up may have resulted in the cataclysmic event some 65 million years ago that destroyed the dinosaurs.

Researchers from Southwest Research Institute and Charles University (Prague) have been studying the asteroid (298) Baptistina, combining their observations with numerical simulations to model the impact event. As the theory goes, Baptistina’s parent body, some 170 kilometers in diameter, was hit by another asteroid approximately 60 kilometers wide. The result: The Baptistina asteroid family, a cluster of fragments in similar orbits that once included 300 bodies larger than 10 kilometers and 140,000 bodies larger than one kilometer.

Asteroid strike on Earth

With all the characteristics of a carbonaceous chondrite meteorite, the Baptistina parent asteroid makes a nice match for the impactor that created the Chicxulub crater in the Yucatan. Sediment samples show that it, too, had a carbonaceous chondrite composition, and the team’s simulations produced a ninety percent probability that it was indeed a member of the Baptistina family. Moreover, the simulations indicate that the lunar crater Tycho may also have been produced by an impactor with a Baptistina pedigree.

The original breakup is thought to have occurred some 160 million years ago, after which the fragments’ orbits would have evolved as they absorbed sunlight and re-radiated energy away as heat. Many of the fragments escaped the main asteroid belt and became potential Earth-crossers. The researchers believe that about two percent of these objects actually went on to strike Earth. Call it the ‘Baptistina bombardment,’ a surge in impacts that peaked 100 million years ago.

“We are in the tail end of this shower now,” says William Bottke (Southwest Research Institute). “Our simulations suggest that about 20 percent of the present-day, near-Earth asteroid population can be traced back to the Baptistina family.”

The impact histories of both Earth and Moon seem to support the supposition, showing a two-fold increase in the formation rate of large craters over the past 100 to 150 million years. That should make an emphatic point about the asteroid belt: Its history of collision and orbital change may well play a significant role in the history of our planet. We need to develop and deploy the tools that can alter the orbits of potential impactors, or do we want to assume that our inadequate catalog of Earth-crossing objects will give us time enough to act?

The paper is Bottke et al., “An asteroid breakup 160 Myr ago as the probable source of the K/T impactor,” Nature 449 (September 6, 2007), pp. 48-53 (abstract).


TOPICS: Miscellaneous
KEYWORDS: asteroid; baptistina; bolide; breakup; catastrophism; chicxulub; chondrite; cretaceous; dinosaur; dinosaurs; godsgravesglyphs; impact; paleontology; stalactites; stalagmites; tertiary
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1 posted on 09/05/2007 11:55:03 AM PDT by LibWhacker
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To: SunkenCiv

Catastrophism ping.


2 posted on 09/05/2007 11:56:12 AM PDT by Lurker ( Comparing moderate islam to extremist islam is like comparing smallpox and ebola.)
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To: LibWhacker

My Bad!!!

3 posted on 09/05/2007 11:58:00 AM PDT by presidio9 (Islam is as Islam does.)
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To: presidio9

LOL! I don't think so

4 posted on 09/05/2007 12:05:05 PM PDT by qam1 (There's been a huge party. All plates and the bottles are empty, all that's left is the bill to pay)
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To: LibWhacker
I thought it was Global Cooling......
5 posted on 09/05/2007 12:06:20 PM PDT by Rummyfan (Iraq: it's not about Iraq anymore, it's about the USA!)
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To: LibWhacker
carbonaceous chondrite

That would be the mother lode in the Tycho crater if this proves out. Set up the moon base there.

6 posted on 09/05/2007 12:08:20 PM PDT by RightWhale (It's Brecht's donkey, not mine)
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To: LibWhacker

We need one of those laser thingies like they had on that Star Trek episode where Kirk becomes an Indian.


7 posted on 09/05/2007 12:09:11 PM PDT by Disambiguator (What's the temperature, Albert?)
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To: presidio9

People who break up asteroids leading to the extinction of large land animals are 17 percent more likely to post duplicate threads sniffed out by former dromedaries.

Where have you been hiding?


8 posted on 09/05/2007 12:12:01 PM PDT by dmz
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To: LibWhacker

Any time a couple breaks up, it can be traumatic for those who have to deal with the aftermath.


9 posted on 09/05/2007 12:13:19 PM PDT by CharlesWayneCT
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To: Rummyfan

Just wait a week. it will be something else again.


10 posted on 09/05/2007 12:13:46 PM PDT by Nathan Zachary
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To: LibWhacker

Didn’t Velikovsky write about something like this 50-75 years ago - and get derided as a crank?


11 posted on 09/05/2007 12:14:15 PM PDT by CatoRenasci (Ceterum Censeo Arabiam Esse Delendam -- Forsan et haec olim meminisse iuvabit)
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To: Nathan Zachary

Just wait a week. it will be something else again.

Right. The words “may have” makes me stop reading. It’s a theory - an opinion and everyone has one. I guess they have to come up with something now and they to keep on the gravy train. Give me proof, darn it!


12 posted on 09/05/2007 12:18:18 PM PDT by Bitsy
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To: dmz
Where have you been hiding?

Once I figured out how to get the straight jacket off, the orderlies weren't that hard to out-run. The trick is you have to dislocate a shoulder first. I learned it from Mel Gibson in Leathal Weapon II (a highly underrated sequel in spite of Danny Glover).

13 posted on 09/05/2007 12:18:49 PM PDT by presidio9 (Islam is as Islam does.)
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To: LibWhacker

What about the theory that they mostly died of a global deluge ?


14 posted on 09/05/2007 12:19:55 PM PDT by SirLinksalot
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To: LibWhacker

15 posted on 09/05/2007 12:24:57 PM PDT by G8 Diplomat (It's campaign season. Let's rumble!)
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To: SirLinksalot

No such theory.


16 posted on 09/05/2007 12:29:09 PM PDT by doc30 (Democrats are to morals what an Etch-A-Sketch is to Art.)
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To: doc30

No conflict with Poe’s law, however.


17 posted on 09/05/2007 12:30:07 PM PDT by js1138
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To: BushFault

18 posted on 09/05/2007 12:32:21 PM PDT by evets (beer)
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To: CatoRenasci
You are absolutely correct. I once asked a science professor about Velikovsky's theory and the prof told this lowly student it was ridiculous.
19 posted on 09/05/2007 12:34:31 PM PDT by WHATNEXT? (That's PRESIDENT BUSH (not Mr.)!!)
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To: G8 Diplomat

Love that cartoon!!


20 posted on 09/05/2007 12:35:09 PM PDT by Pyro7480 ("Jesu, Jesu, Jesu, esto mihi Jesus" -St. Ralph Sherwin's last words at Tyburn)
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