[ExI] Time lapse film of exploding star

[BillK]

On Sun, 11 Sept 2022 at 15:27, spike jones via extropy-chat
<extropy-chat at lists.extropy.org> wrote:
>
> Ja BillK, but if you do the calculations on that it seems like it would take trillions of years in most cases for all the momentum to be radiated away in gravitational waves, unless those black holes somehow formed dang close together to start with (how?) or the angular momentum was canceled up from enormous accretion discs (where did those come from?) as the black holes grew from matter in the disk.  This latter is the only thing I can imagine: our models of how much stuff was available in the old days are wrong.  There must have been a lot more stuff in the old days to make those black holes form close together and grow really big. Heh.  That's an exciting possibility: the standard model is wrong.
>
> None of the models I can imagine fit very well with this many merger events, and none of them which had been proposed before the instrument was turned on suggested there would be this many, even within a coupla orders of magnitude.  As I recall, the most optimistic LIGO promoter agreed  we would be lucky to see an event in any given decade, but felt it was worth building anyway, for a negative result is a result.
>
> Well now.
>
> spike
> _______________________________________________


Well, I am far out of my depth now in this discussion,  :)   but there
seem to be many papers around agreeing with Wikipedia.
Gravitational waves are slowly radiating energy and momentum away as
the orbiting pair gradually move closer together.
The final 'chirp' that LIGO detected is the end of a long process.
This long pdf about gravitational waves seems to know what it is talking about.
(Which is lucky, 'cause I don't!).  :)

<http://www.physics.usu.edu/Wheeler/GenRel2013/Notes/GravitationalWaves.pdf>

BillK