[ExI] Fermi Paradox and GRB bursts

[Dan]

> On Wednesday, October 8, 2014 3:38 AM, Anders Sandberg <anders at aleph.se> wrote:
> Dan<danust2012 at gmail.com> , 8/10/2014 1:57 AM:

>> Just speculating: Could GRBs have secondary effects on planetary
>> systems, such as burning off too many volatiles (which are then
>> not available, say, for cometary impacts on young worlds?) and
>> shaking up stability (say, causing another heavy bombardment in
>> a system by knocking asteroids off stable/nonintersecting orbits)?>

> No. 100 kJ/m^2 deposited in a few seconds is only about 100
> times the solar heating: not enough to vaporize much, and the
> lost volatiles can start condensing immediately. A 20 second
> burst can ideally vaporize 705 g/m^2 of ice, less than a cm deep.

I'm wondering if it's enough to do widespread damage -- not necessarily burn everything off. Obviously, a GRB hit in early solar system development might have a bigger impact, though it'd have to get through higher densities of gas and dust. Then again, this might be a double-edged sword -- maybe helping to trigger more planet formation, so not necessarily a filter against complex life. (Presuming planet formation is, overall, better for the formation of complex life.)

> Closer to the burst things might be worse, of course.

Closer would be worse, yes, though I was wondering about something would be widespread enough to act as _the_ filter. Reckon this ain't it.

Regards,

Dan
 My nanotech apocalypse story "Succession" can be previewed at:
http://www.amazon.com/Succession-ebook/dp/B00F02DLNG
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