Lee Daniel Crocker wrote:
> Isn't that volume small enough for a gamma ray burster to wipe out?
Nope. GRBs only last a few minutes, which means they only irradiate one hemisphere of a planet. The resulting ecological catastrophe might be a problem for primitives like us, but anyone who can plant a colony in another solar system is obviously capable of building completely closed life-support systems. Also, anything that is buried to a decent depth would be unharmed even on the facing hemisphere (so mines, military command centers, subsea bases and other such facilities would escape the destruction).
Besides, charting nearby explosive hazards (supernovae, GRB precursors, and so forth) would seem to be a basic safety measure for such a civilization. Unless you are going to propose a really unusual explanation for GRBs, we should expect our E.T.s to know about the hazard before it actually happens. With fairly modest preperations they can weather the whole thing with minimal (<10%) casualties.
Billy Brown, MCSE+I
ewbrownv@mindspring.com