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).
Yep.. breakups are hard on everyone.. LOL
You know what makes liberals mad? The fact that Dinosaurs died and made room for man.
Once I figured out how to get the straight jacket off, the orderlies weren’t that hard to out-run.
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My problem is the opposite. They keep trying to take the thing off and I keep trying to put it back on. I’ve really been enjoying the Barnaby Jones reruns they show here at the, uh, farm.
Stellar couple breaks up: pet dinosaurs hit hardest!!
The odds of two asteroids in the vastness of space colliding within the gravitational pull of earth has to be monumentally hugh.
And I STILL love how these ‘asteroids’ only targeted dinosaurs! All other life on this planet escaped harm...
What gives you this idea?
Um, that's not exactly how things are supposed to have happened...
YEC INTREP
fyi
That religious belief was abandoned by early creationist geologists--who were trying to prove the global flood--about 1830.
Name names please.
Reverend Adam Sedgwick, Woodwardian Professor of Geology at Cambridge University, and President of the Geological Society of London.
An article describing the capitulation of the last major holdout for the global flood in geology (made during a speech on February 18, 1831) appears here.
Names, please.
Must’ve been raining iridium that day!
Dale: No, but my dad does. He can't even sit on the toilet some days.
I'm not saying planets can't collide (in fact they now think that's how the moon was created), but that was very early in the history of the solar system. I think mainstream scientists believe things have been pretty stable since those early days of the "heavy bombardment," at least when it comes to planets.
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