So this article confused me.
After digging around, the masses of these Black Holes are in the forbidden zone, where there shouldn't really be Black Holes of that size because of how they are formed.
They are usually either bigger or smaller depending on their origin. They could be second or third generation Black Holes, which would be unlikely due to the probability of them forming in close neighborhood. So what their reason for existing there are questions that should lead to some interesting answers if we ever get to the bottom of it.
Can someone explain how is it possible for black holes to even collide? Wasn't the usual expanation that time goes faster (for you, slower for outside observer) as you approach the black hole singularity and that it stops exactly as you "get there"? If this is true the black holes never actually collide. They just endlessly spin closer and closer. For the outside observer it taking infinite time before they actually "touch"?
Or do we just call it a collision if they simply get as close to each other as to be within the event horizon of the other?
If the former and we see these true collisions, how is it not a proof the age of the universe is infinite ? If we see events that are supposed to take infinitely long to occur?
An observer falling into the black hole would not observe any distortion in time. They would simply fall in, under the influence of gravity. From the perspective of a far-away observer it would look as if time is slowing down as the photons would take increasingly longer to escape. At the event horizon the photons would effectively be held in place. Eventually though, the last photon will have escaped and you will just observe a slightly larger black hole.
So the merger definitely happens from the point of view of the black holes. We might observe odd artifacts but they would eventually fade away.
> From the perspective of a far-away observer it would look as if time is slowing down as the photons would take increasingly longer to escape.
Photons travel at the speed of light always, that's what Einstein told us.
So rather, the observed energy (frequency) of the photons decreases, and it takes longer between each photon.
At least that's my understanding.
They can merge event horizons on a finite timescale from the outside and still take an infinite amount of time to merge singularities or whatever it is that singularities do when they meet up in the privacy of an event horizon.
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?
There are no medium sized bkack holes. As far as we look back in time with james webb,the largest are already there.
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"?
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.
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.
Black holes can have a relativistic jet. M87 has one that extends ~5000 light years.
These jets can kill from a long distance.
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
then there are the jets the black holes may form, and I wouldn't like to pass through one
Except black holes can be a lot more massive than the biggest stars.
Which is true, but also just means you need more distance. And if there is anything in space it is distance.
Thanks for that. I guess I had always assumed that over a long enough time frame, black holes would eventually swallow everything.
What about the huge gravitational waves?
inconsequential for the most part, gravity doesn't interact directly with matter (which I understand, might be still quite counterintuitive to many).
I do wonder though if it would be possible for the "ripple" to deorbit us (or any other body).
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.
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
The models are constrained by what is known at the time they are built - those that clash with existing observations are discarded while those that don't, get published.
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?
There just isn't a way to make black holes that big from the collapse of stars when they go supernova.
So maybe both of these black holes formed from earlier mergers of smaller black holes. Or maybe there are other ways to make larger black holes we don't know about. They are in a range of mass we don't really expect to see theoretically.
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?
the extra mass is converted into energy in the form of gravitational waves (maybe other forms too idk but this is part of it)
Entire solar masses being lost to gravitational waves, like the voltage drop across a resistor, is a humbling prospect.
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.
but that's the time that passed here... it sounds like a mind-warpingly different perspective might have been seen there
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.
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.
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?
Rather confused. 225 solar masses isn’t gigantic by any means
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?
Nothing is too big to collide, the issue here are the initial masses which are bigger than expected from core-collapse stars
[deleted]
The situation you describe is impossible. "If you have a very large positive number that is less than zero, what happens?"
What's the contradiction in the black hole setup?
If one is within the other's event horizon, they have already collided (and are now surrounded by a common event horizon).
I'm not even sure what it would mean for two black holes to be too big to collide, or where that became some kind of constraint.
I thought it was just thought that it would take too long for them to spiral into each other for it to have happened enough times in our universe
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.
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 ...)
All you really need to know for the moment is that the universe is a lot more complicated than you might think, even if you start from a position of thinking it’s pretty damn complicated in the first place.
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.
Thanks – I changed it (earlier today) to:
Black hole merger challenges our understanding of black hole formation
“Black hole merger detected that defies theoretical boundaries.”
Still not clear to me how this "contradicts known models for stellar evolution".
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.