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Re: Impacts and ETs



Bill,
Read paleontologist Peter Ward's book, "Rare Earth".  Some of your
questions are addressed (although not necessarily answered) there.

<pb>
--



On Sat, 12 Feb 2005 11:47:41 -0500 "Thomas R. Holtz, Jr."
<tholtz@geol.umd.edu> writes:
> > From: owner-dinosaur@usc.edu [mailto:owner-dinosaur@usc.edu]On 
> Behalf Of
> > Joe Cantrell
> >
> > Assuming, as most people do, that Chicxulub was responsible for 
> the K-T extinction, which paved the way for mammalian
> > radiations culminating in high intelligence, how would the 
> apparent dependence of the latter on a pure chance event
> > affect estimates of the frequency of intelligent life in the 
> Galaxy?
> >
> 
> Well, given our fantastic sample size of inhabited planets, we can 
> say that it decreases the frequency by exactly 2.376%...  Plus or
> minus 100%.
> 
> Seriously, this question (although interesting) can only be 
> approached with massively huge, ultra fast arm waving. This is a 
> science
> fiction question, not a science question. (That doesn't mean it is a 
> BAD question: I am a long time science fiction fan!!)
> 
> So we can't constrain ANY of the variables in this. As others have 
> pointed out, we have no evidence that the K/T extinction was
> necessary for the evolution of intelligence. It might have evolved 
> if the dinosaurs had stayed in charge, either among the dinosaurs
> or among the primates (who may well have evolved into recognizably 
> primate-y things even with the K/T extinction).
> 
> Hope this helps,
> 
>               Thomas R. Holtz, Jr.
>               Vertebrate Paleontologist
> Department of Geology         Director, Earth, Life & Time 
> Program
> University of Maryland                College Park Scholars
>       Mailing Address:
>               Building 237, Room 1117
>               College Park, MD  20742
> 
> http://www.geol.umd.edu/~tholtz/
> http://www.geol.umd.edu/~jmerck/eltsite
> Phone:        301-405-4084    Email:  tholtz@geol.umd.edu
> Fax (Geol):  301-314-9661     Fax (CPS-ELT): 301-405-0796
> 
>