[ExI] blackholes at home

Stuart LaForge avant at sollegro.com
Sat Apr 20 21:09:53 UTC 2019

Spike wrote:

> I have always found it crazy amazing how quickly that last little bit of
> rotational energy bleeds away when two black holes collide.  If you do the I
> * R * omega^2 calculation before the merger and after, we know how to
> calculate the distance between the two black holes before collision (because
> we know their masses and their rotational frequency) and we know how far
> they had to fall inward, even a Newtonian guy can calculate how much energy
> that was that just went away and (SURPRISE) it agrees with what the LIGO
> people tell us.

Yup. It's completely astonishing that two singularities can collide so  
quickly when they are supposedly zero-dimensional point masses that  
have no cross-sectional area. Of course if you believe that they are  
true point masses, they could still be orbiting one another after the  
black holes have merged. Since what happens in a black hole stays in a  
black hole, we would be none the wiser.

> I confess to having been a flaming unbeliever, but now I found religion on
> LIGO: that was the most important scientific instrument since Hubble, and in
> some ways it was more informative than Hubble.

Amen. LIGO is like an invention that created its own whole new  
category of technology. Like a retina for gravitational waves and its  
creating a whole new field of science. Gravitometry? Gravitometrics?  
Gravitoscopy? What do you even call it?

Stuart LaForge

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