This was OT on a sci-fi group I view. On topic here.

Most of us will remember that in 2016, the LIGO gravity telescope
detected two black holes merging for the first time - the 'chirp' emitted
in the form of gravitational waves as they spiraled in towards each
other was eerie.

Keith Lynch, over on rec.arts.sf.fandom, pointed out something I'd
missed. The merger in 300 ms converted 3 solar masses to
gravitational waves. The energy emitted is very high, even on cosmic
scales - 5*10^43 Joules, and GW150914 briefly emitted more energy
that all the stars in visible universe.

That energy was emitted as gravitational waves, not light. The
'Schwinger limit' which puts a cap in the amount of EM energy
can be in a given volume. This event had 10^5 times that limit.

That merger took place 1.3. billion light years away. When it reached
the Earth, the amount of energy was such that, had it been visible light,
it would have been not only a naked eye event, it would have been 6
times the light of the full moon, and bright enough to read by.

This was an event the magnitude of which would warm the cockles of
Doc. EE Smith's heart. But it was only the first - bigger events have
been seen since.

The Universe is a strange and wondrous place.

https://en.wikipedia.org/wiki/First_observation_of_gravitational_waves

https://gravityphysics.com/2016/02/11/gw150914-enormous-gravitational-wave-energy/

pt

comments include

>
> Could you clarify "briefly"? There is more than one
> reason to not try to read in a lightning storm.
> I suppose you have to sometimes, in a certain kind
> of movie for instance. Shall I go and check
> _The Rocky Horror Picture Show_? I think I won't.

That datum is in the OP. 300ms.