Black hole merger challenges our understanding of black hole formation
40 comments
·July 14, 2025misja111
daedrdev
There are no medium sized bkack holes. As far as we look back in time with james webb,the largest are already there.
berkes
Just guessing, but maybe the common situation is that one ever growing black hole absorbes small ones? But that two of these large ones merging "should not happen"?
debugnik
The article fails to explain why this event challenges our understanding of black holes. Did we expect such big masses to spiral for much longer or something? Why was this collision supposed to stay unstable?
ErigmolCt
225 solar masses… that's just wild. We keep building these models that tell us mergers like this shouldn't happen, and the universe keeps dunking on them
Stevemiller07
It’s impressive how LIGO and Virgo keep pushing the limits of what we thought was possible. Each new event seems to open more questions than it answers.
gmuslera
Greg Egan's Diáspora starts with the merger of two neutron stars, and that causes a lot of trouble in this side of the galaxy, don't want to imagine what would it be with 2 massive blackholes for the nearby galaxies.
ars
It wouldn't do anything special actually. A black hole from a distance does nothing a sun can't do.
Black holes only become destructive/powerful when you are very close to them.
To elaborate: A black hole is mass, a sun is mass. From a distance there's no difference. The only difference is up close - you can get a lot closer to a black hole dramatically increasing the gravitational force.
But from a distance? Nothing special.
ErigmolCt
We often imagine them as space vacuums sucking everything in, but they're really just compact mass: spooky only if you get way too close
djmips
Black holes can have a relativistic jet. M87 has one that extends ~5000 light years.
These jets can kill from a long distance.
ikari_pl
then there are the jets the black holes may form, and I wouldn't like to pass through one
misja111
What about the huge gravitational waves?
abrookewood
Thanks for that. I guess I had always assumed that over a long enough time frame, black holes would eventually swallow everything.
thaumasiotes
Way to headline.
The numbers in the article suggest a violation of conservation of mass:
> Today, the LIGO Collaboration announced the detection of the most colossal black hole merger known to date, the final product of which appears to be a gigantic black hole more than 225 times the mass of the Sun.
> GW231123, first observed on November 23, 2023, seems to be an unprecedented beast of a black hole merger. Two enormous black holes—137 and 103 times the mass of the Sun—managed to keep it together despite their immense combined mass
Is the explanation here "225 is a nice round number, and 240 is technically 'more than' that", or "a lot of mass evaporates into other forms of energy when black holes merge", or "during a merge, it becomes possible for matter to escape an event horizon", or what?
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)
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.
david38
Rather confused. 225 solar masses isn’t gigantic by any means
NooneAtAll3
it's above what's considered possible to create by usual star collapse means
https://en.wikipedia.org/wiki/List_of_most_massive_stars lists only 2 stars more massive than that
thaumasiotes
So if you have two black holes within each other's event horizons, but they're too big to collide, what's supposed to happen instead?
idiotsecant
I don't know if there's ever been a more perfect setup for a your mother joke, but sometimes art is the brush strokes you don't make.
Bluestein
I'll counter Debussy ("the space between the notes ..." and all that :)
... and give it a go: "Yo mama is so big she can't even collide with a black hole" (or something ...)
gnabgib
Title needs an edit (maybe the clickbait algo): Astronomers Detect a Black Hole Merger That’s So Massive It Shouldn’t Exist - although, it's not a great title.
imoverclocked
“Black hole merger detected that defies theoretical boundaries.”
abrookewood
Still not clear to me how this "contradicts known models for stellar evolution".
sherdil2022
Our understanding of this universe constantly changes. We all know those - Earth is flat or it is center of universe, on and on.
The black hole is happening. So it exists. So either the observations are wrong or the undeying assumptions are wrong or math / physics we are using to make sense of the event is wrong.
Click-bait articles serve no purpose in advancing science.
I don't get it. There are black holes that have millions of sun masses. The current theory is that these were formed by many consecutive mergers. What then makes this 225 sun mass merger so large that it shouldn't exist?