[ExI] Old Chemically Mature Galaxies and Fermi Paradox

[Jeff Davis]

I Googled it, and Wikipedia offers the following:

Bursts can last from ten milliseconds to several minutes, although a
typical burst lasts 20–40 seconds.

Jeff Davis

On Sat, Nov 5, 2011 at 3:51 PM, Jeff Davis <jrd1415 at gmail.com> wrote:
> On Sat, Nov 5, 2011 at 3:07 AM, Anders Sandberg <anders at aleph.se> wrote:
>
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>                           <snip>
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>> One reset mechanism that was suggested by Milan Circovic (and then, with
>> some minor input from me, developed by him into a paper with Robert
>> Bradbury)
>
> Is there a link to that paper?
>
>> is that gamma ray bursts acts as the reset. The data suggests that
>> gamma ray bursts were much more common in the past, and it is not hard to
>> imagine that every time one hits a biosphere it slides back to a simple
>> stage.
>
> Regarding the intensity, and consequent destructiveness of a GRB:  I'd
> like to get some idea of the damage as a function of  distance.  How
> close for utter obliteration (ie planet flat out gone)?  how close to
> reduce the entire planet to scorched rock?  How close for scorched
> rock on one side?  How close for atmosphere stripping?  How close for
> surface searing without loss of atmosphere? And finally, how close for
> a severe, transient, non-lethal climate "excursion" with substantial
> survival on the planet's far side?  (This last question assumes that
> the duration of the GRB is shorter than half the  rotation period of
> the affected planet.  So one last question:  What's the typical
> duration of a GRB?)
>
> Best, Jeff Davis
>
>         "Everything's hard till you know how to do it."
>                                     Ray Charles
>