[FPSPACE] Fear and Loathing on the Launch Pad

[Jens Kieffer-Olsen]

-----Original Message-----
From: E.P. Grondine [mailto:epgrondine at hotmail.com] 
Sent: Thursday, April 30, 2009 10:28 AM

> > You are not saying that one of the most researched
> > ELEs - the Chicxulub impact - was caused by a comet,
> > are you?
>
> Yes.
> In point of fact, we have a sample of the KT impactor.
> If you image google KT-fossil you should see an image of
> the fossil carbonaceous chondrite (comet) recovered from
> a core.
> In other words, Morrison's impact hazard estimates are a
> "crock" as we say here in the US, and Clube and Napier
> were correct.

 Well, well, well, Ed - but you seem to have forgotten to
 update wikipedia
 http://en.wikipedia.org/wiki/Chicxulub_crater :

 "On September 5, 2007 a report published in Nature proposed
 an origin for the asteroid that created Chicxulub Crater.
 The authors, William F. Bottke, David Vokrouhlický, and
 David Nesvorný, argued that a collision in the asteroid belt
 160 million years ago resulted in the creation of the
 Baptistina family of asteroids, the largest surviving member
 of which is 298 Baptistina. They proposed that the "Chicxulub
 asteroid" was also a member of this group. The connection
 between Chicxulub and Baptistina is supported by the large
 amount of carbonaceous material present in microscopic
 fragments of the impactor, suggesting the impactor was
 a member of a rare class of asteroids called carbonaceous
 chondrites, like Baptistina. According to Bottke, the
 Chicxulub impactor was a fragment of a much larger parent
 body about 170 km (105 mi) across, with the other impacting
 body being around 60 km (40 mi) in diameter."

 Checking further I learn from
 http://spaceknowledge.net/?tag=chicxulub-crater

 [...] the team found a 90 percent probability that the object
 that formed the Chicxulub crater was a refugee from the
 Baptistina family.  These simulations also showed there was
 a 70 percent probability that the lunar crater Tycho,
 an 85 kilometer crater that formed 108 million years ago,
 was also produced by a large Baptistina fragment. Tycho is
 notable for its large size, young age and its prominent rays
 that extend as far as 1,500 kilometers across the Moon.
 Vokrouhlicky says, "The probability is smaller than in the
 case of the Chicxulub crater because nothing is yet known
 about the nature of the Tycho impactor."

--
Jens Kieffer-Olsen
Slagelse, Denmark