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What happens when black holes collide? Does one black hole “consume” the other? Do they become a larger black hole? Does it get more dense or just larger?
I wonder how the singularities would merge with each other.
I wonder what would happen if one black hole shot through another one at high relativistic velocity, instead of spiralling towards one another.
Man, that is some seriously interesting phenomena:

"The black holes appear to be spinning very rapidly—near the limit allowed by Einstein's theory of general relativity," explains Charlie Hoy of the University of Portsmouth and a member of the LVK. "That makes the signal difficult to model and interpret. It's an excellent case study for pushing forward the development of our theoretical tools."

Does the spinning of a spherical object cause any gravitational waves?
> the 225-solar-mass black hole was created by the coalescence of black holes each approximately 100 and 140 times the mass of the Sun.

Does this mean that 15 solar masses were converted into energy? Because that's a LOT of energy.

I've always thought the event horizon for a black hole has to be spherical.

But my physics intuition tells me that as two of them merge, the resulting BH should have a "peanut" shape, at least initially.

And maybe it can keep having an irregular shape, depending on the mass distribution inside it?

From our perspective there is no event horizon since the collapsing star has not reached the black hole state. In fact it takes infinite amount of time from the point of view of an external observer for the event horizon to form.

In almost all situations it does matter as the collapsing star will behave as it is a black hole. But for the merge of black holes it is significant as it allows to release energy as there is no event horizon.

A month ago, the proposed NSF budget would shut down one of the two LIGO observatories in the US, wrecking its ability to triangulate the location of events such as this black hole merger. A shutdown would also severely damage the noise margins and detection rate. Does anyone know if the shutdown is still planned? (I couldn't find any recent info.)

https://www.science.org/content/article/trump-s-proposed-cut...

When I read 'news' like that, I 'compare' myself to the thing. And then I think how this 'thing' can swallow me, everyone around me, everything as far as the eye can see (thank you light pollution, we can only see the moon and perhaps 5-6 more 'things' out there (ffs!)) and then we will be 'no more'.

But then I use the voice of Djimon Hounsou and the quote from the Gladiator "but not just yet".

Boring press release without any real details. I wish the paper would trend not an empty press release announcing the announcement.
Kind of amazing that LIGO/Virgo/KAGRA can even detect and decode something that extreme
Everything in the universe is massive because we are just so small. Everywhere but within the confines of our solar system, calling something massive is a meaningless endeavour, it’s so big nobody has any idea how to appreciate it, and then there is always going to be something bigger which makes that black hole look tiny
I'm in dire need of good news, so help me see it in an optimistic lens: can you imagine a path (even very indirect) where this kind of discovery ends up having a practical use that makes real life better here on Earth ?

(I'm not in the age-old debate about "is research useful ?" - I agree the answer is yes ; I just have a failure of imagination that prevents me from answer the question "how is this research going to be useful in the long run ?")

What is the budget outlook for LIGO?

Was the budget cut in the BBB passage last week?