[ExI] Gravitational Waves Detected By LIGO!

[Anders Sandberg]

On 2016-02-11 17:50, spike wrote:
>
> Anders, cool, but we need to know how GW energy would interact with 
> matter before we conclude that it would nuke biomes.

OK, I was using the normal style of energy estimates used in supernova 
xrisk considerations.

Now, for gravitational waves being lethal, the strain must presumably be 
large enough to cause induction of forces that are damaging. To a ~1 m 
object like a human, you probably need a strain on the order of more 
than 1/100 to induce damage (1/10 seems really likely to do it). The 
strain scales as 1/r, so given that the detected strain here was on the 
order of 10^-19, we get dangerous strain when 10^17 times closer to the 
source (which is at around 410 Mpc). That is, we get dangerous strain 
within 126,526 kilometers.

So I would not worry about gravity waves.

http://arxiv.org/abs/0911.3889 has some estimates for EM effects, which 
look like they are 10^-13 times the gravity waves. So that looks pretty 
safe: about a year of solar energy output per solar mass radiated away 
as gravity waves. Presumably this could scale up if the EM environment 
near the holes was stronger.


-- 
Anders Sandberg
Future of Humanity Institute
Oxford Martin School
Oxford University

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