RE: starship-design: Fermi's Paradox - Drake's Equation will have to be rewritten

["L. Clayton Parker" <lparker@cacaphony.net>]

I would argue that it is next to impossible for ANY civilization to survive
to the point where they could predict AND PREVENT a GRB in sufficient
proximity to wipe them out. As a matter of fact (without really having
looked at the math) I would bet simply surviving such an event is probably a
major feat, although probably not impossible. Does anybody know of a good
gamma ray shield?

Lee Parker
>
> Consider when it might have happened last near enough to affect life on
> Earth... ? Like when? I have a couple of suggestions - about two billion
> years ago, quite close; and about 250 million, not so close. The first
> relates to a study which dated the divergence of life from a
> common ancestor
> ~~ 2 billion years ago - that conflicts with every fossil from
> prior to that
> time. But what if a GRB had wiped out all but one species? The
> other date is
> the great Permian extinction, which wiped out most life on land and in the
> sea. It's been tied to a catastrophic overturn in the ocean that released
> huge amounts of CO2. Earth at that time had one continent and a global
> ocean. If the GRB hit the ocean side then life wouldn't notice it
> much - but
> what if that acted as trigger for the overturn? Some change in acidity or
> greenhouse processes from massive amounts of upper atmospheric chemistry,
> which changed the thermal balance of the ocean...

> If anything is a strong argument for a galaxy-spanning civilisation it's a
> GRB - if you want to think in the long term and survive then GRBs
> need your
> attention. How do you stop them? By knowing how they form for starters. No
> one is still too sure.
>