[ExI] blackholes at home
avant at sollegro.com
Sat Apr 20 21:09:53 UTC 2019
> 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?
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