> 1) The target civilization is assumed to have self-sustaining colonies in
> several solar systems spread across a volume of at least a few dozen cubic
> light-years.
Isn't that volume small enough for a gamma ray burster to wipe out?
-- Lee Daniel Crocker <lee@piclab.com> <http://www.piclab.com/lcrocker.html> "All inventions or works of authorship original to me, herein and past, are placed irrevocably in the public domain, and may be used or modified for any purpose, without permission, attribution, or notification."--LDC