John Clark [SMTP:jonkc@worldnet.att.net] wrote:
> No need to conjure up exotic stuff like Hypernova's or Gamma Ray 
Bursters,
> just a garden variety supernova would probably do the trick if it were 
close enough.
> Neutrino are normally harmless but the flux from one of these monsters 
would
> be so incredibly enormous all life would probably be sterilize within a 
few dozen cubic
> light years. The other unpleasant aspects of a supernova could be 
shielded against but
> not neutrinos, it's hopeless, you're fried.
A classic suggestion. However, interstellar space is more than big enough to provide protection.
A typical supernova would have a total energy output of something like 
10^44 ergs.  Applying a little basic geometry, that gives us an energy 
density of 2x10^10 ergs per square meter at a distance of 100 million 
kilometers, which will certainly do a lot of damage.  However, at a 
distance of 1 light-year (9x10^12 kilometers), the energy density drops to 
less than one erg per square meter.  That isn't even enough energy to 
damage electronics, let alone harm people.
Conclusion: Despite their reputation, supernovae are only dangerous to 
people in the same solar system.  They certainly aren't a threat to 
interstellar civilizations.
Billy Brown, MCSE+I
ewbrownv@mindspring.com