[ExI] Fermi Paradox and GRB bursts

[Anders Sandberg]

BillK <pharos at gmail.com> , 1/10/2014 12:01 PM:
<http://arxiv.org/abs/1409.2506> 
Quote: 
Using recent determinations of the rate of GRBs, their luminosity 
function and properties of their host galaxies, we estimate the 
probability that a life-threatening (lethal) GRB would take place. 
We find that the probability of a lethal GRB is much larger in the 
inner Milky Way (95% within a radius of 4 kpc from the galactic 
center), making it inhospitable to life. Only at the outskirts of the 
Milky Way, at more than 10 kpc from the galactic center, this 
probability drops below 50%. 
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One more factor pointing to life being rare and occurring far enough 
apart that contact with other aliens will be unusual. 
I am sceptical of their conclusion. While a GRB no doubt can cause mass extinctions they do not remove biospheres: a few cm of water or rock protects against the radiation in their paper. 
The GRB rate is also low enough that it cannot cause effective synchronization of advanced life a la the Annis/Cirkovic scenario. 

Anders Sandberg, Future of Humanity Institute Philosophy Faculty of Oxford University

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