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From: bpdickson@trillium.waterloo.edu (Brian P. Dickson)
Newsgroups: sci.bio,sci.misc,rec.birds
Subject: Re: animals and Earth's magnetic reversal
Message-ID: <5880@watdragon.waterloo.edu>
Date: 21 Mar 88 20:17:06 GMT
References: <7387@ihlpa.ATT.COM> <460@amethyst.UUCP> <20@denali.UUCP> <5792@watdragon.waterloo.edu> <22@denali.UUCP>
Sender: daemon@watdragon.waterloo.edu
Reply-To: bpdickson@trillium.waterloo.edu (Brian P. Dickson)
Organization: U. of Waterloo, Ontario
Lines: 20
Summary: Appology for flame

In article <22@denali.UUCP> karish@denali.UUCP (Chuck Karish) writes:
>... The hedging in my wording was meant to convey the analytical imprecision
>of the scientific data under consideration, not my personal uncertainty.
I stand corrected. However, references would be appreciated, and can tend to
prevent knee-jerk flames like mine.

>...I thought that this group was interested in wildlife, not geophysics.
Well, certainly, but the Nemesis theory is cross-disciplinary. I would think
it inappropriate to summarise the biological implications without their
geophysical causes.

>The periodicity of mass extinctions that forms the basis for the Nemesis
>theory is based on data with questionable (and much-questioned) statistical
>significance.
The strongest point about the Nemesis theory is that it provide a good
explanation for the irregularity of the reversals, since cometary impacts
are probabilistic, whereas a single-body type intereaction would be periodic
as anything. But I restate the obvious.

Brian Dickson