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From: karish@denali.UUCP (karish)
Newsgroups: sci.bio,sci.misc,rec.birds
Subject: Re: animals and Earth's magnetic reversal
Message-ID: <22@denali.UUCP>
Date: 19 Mar 88 05:47:57 GMT
References: <7387@ihlpa.ATT.COM> <460@amethyst.UUCP> <20@denali.UUCP> <5792@watdragon.waterloo.edu>
Reply-To: karish@denali.UUCP (Chuck Karish)
Organization: Mindcraft, Inc.
Lines: 46

In article <5792@watdragon.waterloo.edu> bpdickson@trillium.waterloo.edu (Brian P. Dickson) writes:
>>During polarity reversals, which probably take ten thousand years or more,
>                                  ^^^^^^^^
>>the earth's magnetic field is probably weak and irregular, and generally
>                               ^^^^^^^^                         ^^^^^^^^^
>>useless for navigating.  The dates of ancient extinctions are not known
>>precisely enough to allow convincing correlations with magnetic reversals;
>                           ^^^^^^^^^^
>>for that matter, the timing of reversals longer ago than ten million years
>>is not known too precisely, either.
>>
>>Chuck
>
>***FLAME ON: AAAAAARGHH!! The 'net is supposed to be used for the dissemination
>of useful information, not freshmen's humble opinions. Not only is your posting
>conjecture, but it is most probably *wrong*!
>***FLAME OFF
>
	[summary of the Nemesis hypothesis follows]
>--
>Brian Dickson,
>closet scientist

My statements were summaries of my readings of carefully-done
scientific studies, as published in refereed journals.  The hedging in
my wording was meant to convey the analytical imprecision of the
scientific data under consideration, not my personal uncertainty.  If
there's a demand for them, I'll post citations to support what I said;
I thought that this group was interested in wildlife, not geophysics.

The periodicity of mass extinctions that forms the basis for the Nemesis
theory is based on data with questionable (and much-questioned) statistical
significance.  It's still a sexy story, though, and makes good copy in
the popular press.

Far from being eclipsed by the paradigm Mr. Dickson refers to, the
information about the timing of magnetic reversals and extinctions
are critical information which must be used to evaluate that paradigm.

Mr. Dickson, if you'd like to come out of your closet, the first step
might be to browse through back copies of _Science_ and/or _Nature_
at your public library, instead of quoting _Popular Science_ to me.
Those magazines might give you a hint of how scientific research is
done, in contrast to the approach that says "Gee whiz, listen to the
trippy things that all these VERY IMPORTANT EXPERTS are saying now!".

Chuck Karish