[ExI] Fermi Paradox and GRB bursts

[Dan]

> On Friday, October 3, 2014 11:37 AM, BillK <pharos at gmail.com> wrote:
> The problem is not just radiation exposure to
> part of a planet. You have to account for
> secondary effects as well. Serious damage to the
> ozone layer and atmosphere damage similar to a
> nuclear winter would affect the whole planet.
> 
> Evolution could be postponed for millions of years.

That would depend on many factors, but my qualitative non-expert view is more than millions, but tens of millions of years to recover, depending on those other factors. Imagine this happened now to Earth. I think it'd be safe to safe, humanity would be wiped out and probably a good chunk of terrestrial life. How long would it be before another intelligent species evolved to carry forth with a technological civilization? If much of terrestrial life is gone, presumably most near contenders -- most of which are near extinction now -- would likely be gone. Maybe some of the primate line would survive, but I don't any small primate would leap up to human level intelligence is a few million years. (This is just my speculation. Hominin brain power did explode in maybe ten million years or so. But the ancestors were larger primates already: bigger base to build on. Just my guess.)

Of course, if the GRB happens earlier in evolution (again, presuming Earth is a good guide to the path and tempo of evolution toward technological civilization), it might not matter as much. For instance, if it happens at the pre-multicellular life stage, it'll still have a big impact, but it's more likely, IMO, unicellular life can recover. (Again, presuming life takes a similar path and a similar speed at getting there, on average, across the universe.)

Regards, 

Dan 
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