Prehistoric meteor shower? |
Prehistoric meteor shower? |
Dec 13 2007, 07:02 PM
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Member Group: Members Posts: 688 Joined: 20-April 05 From: Sweden Member No.: 273 |
A real weird news story from Nature about meteor damage to pleistocene fossils:
http://www.nature.com/news/2007/071212/ful...s.2007.372.html If traces of this meteor shower has been found in both Siberia and Alaska as the story implies, then multiple impactors must have been involved. Such small meterites would lose speed quickly so the airburst must have occurred at fairly low altitude. |
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Dec 14 2007, 08:55 AM
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Dublin Correspondent Group: Admin Posts: 1799 Joined: 28-March 05 From: Celbridge, Ireland Member No.: 220 |
QUOTE The discovery of the 2–5 millimetre holes left by meteorites opens a window into a impact event thought to have happened over Alaska and Russia tens of thousands of years ago. I can't see how this could be possible. They are proposing that millimetre/sub-millimetre meteoric debris could have reached the surface at a sufficient velocity to penetrate bone to a depth of a few millimetres and done so over a geographic area thousands of kilometers across. I don't see that being at all likely - such small particles have a very limited range at such velocities (a few km at most) and if the velocity rises too far they will vaporize and any low altitude airburst that is small enough to generate the debris shower without a cataclysmic shock wave that would have totally destroy the tusks could not be large enough to cause similar effects across such a large range. I would also describe this sort of provenance for evidence as a bit suspect: QUOTE West bought the 60-centimetre tusk for about US$200, and later headed to the warehouse of the company that he bought it from: Canada Fossils. If you ask me it is easier to think that the damage he has detected was caused by someone doing some welding near those tusks at some point in the past rather than micro meteorities peppering mammoths and bison during a prehistoric mega meteor storm. |
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