Re: The Great Filter

Robin Hanson (hanson@hss.caltech.edu)
Mon, 10 Mar 1997 14:52:40 -0800 (PST)

I wrote:
>If multi-celluar life on a planet gets destroyed every 100my, then
>this should happen on average 100 times over 10by. So the chance it
>never happened at any one place is exp(-100) ~= 10^-43 (assuming a
>poisson distribution). So how big is a sphere enclosing 10^43 stars?

Oops again. We're only looking at about 1 billion years of
multicelluar life on Earth, so thats only a filter of size
exp(-10) = 4.5x10^-5.

Robin D. Hanson hanson@hss.caltech.edu http://hss.caltech.edu/~hanson/