[jraines]

the extra mass is converted into energy in the form of gravitational waves (maybe other forms too idk but this is part of it)

[maxbond]

Entire solar masses being lost to gravitational waves, like the voltage drop across a resistor, is a humbling prospect.

[bot403]

I'll underscore your awe by reminding you those solar masses disappeared in only 1 tenth of a second - the length of the gravitational wave signal.

[ikari_pl]

but that's the time that passed here... it sounds like a mind-warpingly different perspective might have been seen there

[IAmBroom]

I think you have it backwards. From the POV of someone near the Event Horizon, other space speeds up. Galaxies begin to spin at noticeable speeds.... But the black holes would appear to be approaching each other at "normal" speeds.

[Bluestein]

Dang

[nine_k]

I suppose nothing but gravitational waves can escape the even horizon — or, rather, gravitational waves are born near / around it, because the black holes bend the space enormously.

OTOH whatever else may be outside the black holes near the merger and count towards their mass for astronomical purposes, such as accretion discs, should be much lighter weight than what's inside the event horizon.

[ars]

Gravitational waves also can not escape. Those waves carry energy, and it's actually energy that can't escape.

The waves are actually made just to the outside of the event horizon.

[berkes]

I always understood that the waves are "made" everywhere, but that only the waves outside the even horizon will escape.

Was my understanding wrong all along?

[ars]

Sort of correct?

Time is halted inside the black hole, so the waves made inside it never show up. Static gravity does show up though, but changes do not.

[thaumasiotes]

> The waves are actually made just to the outside of the event horizon.

How do we feel about this vis-a-vis action-at-a-distance?

[ars]

Gravity does action at a distance. That's its thing.

The reason these waves are not generated from inside the black hole is that, to us, time stops there. For example these black hole mergers aren't actually merging, they are getting closer, and then they time dilate out of existence.

[thaumasiotes]

> Gravity does action at a distance. That's its thing.

Why does it need to travel in waves at the speed of light? If one mass moves, a distant mass is unaffected until the information reaches it. That's the opposite of action at a distance.

[ars]

Your question is confusing. Action at a distance does not imply going faster than light, it means there is some sort of field connecting the two things.