SV: 13 kya: Case Strengthens For Cosmic Explosion Over Canada

[Tommy Tyrberg <tommy.tyrberg@norrkoping.mail.telia.com>]

-----Ursprungligt meddelande-----
Från: owner-DINOSAUR@usc.edu [mailto:owner-DINOSAUR@usc.edu] För MICHAEL
MURPHY
Skickat: den 13 juli 2008 13:03
Till: jrccea@bellsouth.net
Kopia: dinosaur@usc.edu
Ämne: Re: 13 kya: Case Strengthens For Cosmic Explosion Over Canada

I actually quoted GSP's comments to West.  He responded as follows:
   
  
 
  Most discussions cite the usual explanation for impacts, which is true
in most cases. However, that theory fails to explain the Carancas impact
(http://www.universetoday.com/2008/03/18/peruvian-meteorite-may-rewrite-
impact-theories/) or the particles in mammoth tusks. New research hints
at a "tunneling" effect for some impactors, particularly fragmented
ones. In those cases, the leading objects tunnel into the atmosphere and
explode, apparently opening the way for trailing objects to reach ever
closer to the surface. Some bunker-buster bombs work on the same
principle. The first bomb opens a crater, the 2nd digs deeper, and
subsequent ones even deeper.

In simulations, the initial explosions of a highly fragmented comet
appear to be able to push aside the atmosphere and allow the particles
from subsequent explosions to travel with almost no atmospheric
friction. This is all theoretical but explains some seemingly
inexplicable phenomena.
  

This is not exactly new research. The "tunnelling" effect is well known,
and is the explanation that ejecta from a large impact can still have
very high speeds (even escape velocity) when leaving the atmosphere. The
problem with using this phenomenon to explain the particles in the
mammoth tusks is that the creation of the tunnel through the atmosphere
would have some unfortunate side effects in the target area, e. g.
vaporizing any mammoths in the area. 

Tommy Tyrberg