From: Henry Spencer <email@example.com>
Subject: Re: Betelgeuse supernova?
Date: Mon, 8 Apr 1996 17:41:45 GMT
In article <31655AE0.firstname.lastname@example.org> email@example.com writes:
>...I remember seeing another paper that mentioned
>the suspected "periodic" extinction events occurred when the solar
>system was near its greatest out-of-plane (of the galaxy) positions.
Actually, no, this doesn't work out. For one thing, the evidence for
any sort of periodicity in extinction events is extremely weak -- more
an artifact of the statistics than a believable result, at least with
For another, there is no plausible mechanism by which the out-of-plane
excursions could account for such a periodicity, simply because the Sun
doesn't go very far out of the plane of the galaxy -- at least, not with
its present orbital elements -- and the density of known types of objects
does not fall off that sharply with distance from the plane. The Sun's
environment simply doesn't vary terribly much with its out-of-plane
For lots more detail, although not the very latest news, see "The Galaxy
and the Solar System", Smoluchowski/Bahcall/Matthews eds., U of Arizona.
Americans proved to be more bureaucratic | Henry Spencer
than I ever thought. --Valery Ryumin, RKK Energia | firstname.lastname@example.org