Re: Supernova/mass extinction business

[R lindberg + E Winnie <rlindber@telebyte.com>]

On Thu, 19 Jan 1995 larrys@zk3.dec.com wrote:

> 
<snip>
> 
> Okay, I can dig that - but we know the motions of all the stars
> in our vicinity, and a star some 35 lightyears from us that went
> nova _would_ leave a black hole, pulsar or white dwarf whose proper
> motion could be backtracked to that point. 
      I'd like to know how. I think you are making a few non-valid
assumtions, like that the orbit was nearly identical to the suns.
Certainly few, if any, of the stars within 35 lightyears are identical. 
We simply have no idea which stars were with-in 35 lightyears 250m years
ago (well they probibly know a few). 

<snip>
> A relative motion of, say, 10 miles
> per second should still place the object within a sphere of around
> 2500 ly.  There's a lot of stars in that sphere, but the number of
> nova remnants isn't very large.  Backtracking motion to a ring around
> the Earth where such destruction must have originated cannot be that
> hard.
   The problem here is that we can see only a part of the galaxy, a
large part is completely blocked by dust, gas, etc

   Of course a super-nova is speculation, but to dismiss it because we 
don't know where the remnant is, right now, is a little premature.

Ralph

Ralph Lindberg N7BSN Ellen Winnie N7PYK e-mail => dragonsl@scn.org (best
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