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(Big Think)   We've only seen black hole mergers where both black holes were made from matter. What would be different if one of them, instead, were antimatter?   (bigthink.com) divider line
    More: Interesting, General relativity, Black holes, sufficient amount of mass, Gravitation, black hole, quantum rules, gravitational pull, tremendous variety of particle  
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663 clicks; posted to STEM » on 20 May 2022 at 12:54 PM (6 weeks ago)   |   Favorite    |   share:  Share on Twitter share via Email Share on Facebook



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2022-05-20 12:07:27 PM  
they'd be white?
 
2022-05-20 12:59:07 PM  
Nothing, nothing would be different.
 
2022-05-20 1:04:41 PM  
Aren't we still trying to figure out if antimatter even has mass, as opposed to negative mass?
 
2022-05-20 1:05:43 PM  
We've no way to tell one from the other.
 
2022-05-20 1:06:11 PM  
LIGO Feel That Space (The Weeknd Parody) | A Capella Science
Youtube degD69wnZcY
 
2022-05-20 1:14:09 PM  

Stibium: Aren't we still trying to figure out if antimatter even has mass, as opposed to negative mass?


Research ongoing at CERN. Last I heard, antiprotons seem to weigh as much as protons. But they're damned fiddly.
 
2022-05-20 1:17:11 PM  
/mindblown.gif
//naught
 
2022-05-20 1:24:08 PM  
You've likely all seen the rubber sheet analogy for gravity; I figure there are three options, two of which are functionally identicle.

1) space deforms along a fourth spatial axis, we are at the origin, and it can only be positive

2) the metric deforms within normal 4-space, there is neither positive nor negative

3) space deforms along a fourth spatial axis, we are at the origin, and it can be positive or negative

Option 3 would seem to provide similar effects for positive and negative mass in terms of how warped space would affect movement... Until a positive and negative mass came together, at which point they should cancel out.

I am not a physicist, and the preceding is almost certainly nonsense.
 
2022-05-20 1:27:27 PM  
tl;dr: No clue. Likely doesn't make a difference; if it does, we likely can't tell the difference. But, we don't know, so we'll still pay attention & keep an eye out for differences.
 
2022-05-20 1:27:36 PM  
If two back holes merge in space, and light doesn't escape for anyone to see it, does it even antimatter?
 
2022-05-20 1:28:57 PM  

Chemlight Battery: If two back holes merge in space, and light doesn't escape for anyone to see it, does it even antimatter?


You get Lepton Gravity Well O' Soup.
 
2022-05-20 1:42:07 PM  
What if a three-way merger took place between a matter black hole, an antimatter black hole, and a kugelblitz?

They ain't just mattert and antimatter black holes.
 
2022-05-20 1:45:36 PM  

SwiftFox: What if a three-way merger took place between a matter black hole, an antimatter black hole, and a kugelblitz?

They ain't just mattert and antimatter black holes.


What if we put everything on a bagel?
 
2022-05-20 1:50:30 PM  

Mr. Eugenides: Nothing, nothing would be different.


This.

The universe did not stutter when it said 'Nothing comes back out.'

Black holes have 'no hair', meaning that the only properties that matter are mass, charge, and spin. As anti-matter has the same mass, and opposite charge, as ordinary matter, then it would be probable that just like ordinary matter, an anti-matter star would have an average neutral charge.

So even if one of them was a billion solar masses of anti-matter, and the other was a billion solar masses of matter, you'd get the same gravitational wave 'bloop' noise, and a bigger black hole at the end.
 
2022-05-20 1:57:38 PM  

Unsung_Hero: You've likely all seen the rubber sheet analogy for gravity; I figure there are three options, two of which are functionally identicle.

1) space deforms along a fourth spatial axis, we are at the origin, and it can only be positive
2) the metric deforms within normal 4-space, there is neither positive nor negative
3) space deforms along a fourth spatial axis, we are at the origin, and it can be positive or negative


The rubber sheet is just an analogy.  General relativity uses "intrinsic geometry", meaning that the curved spacetime isn't embedded in any higher-dimensional space.  I guess this is like your option (2), although I'm not fully sure I understand what you meant.


imgs.xkcd.comView Full Size
 
2022-05-20 1:57:50 PM  
Marvin Martian - Wheres the Kaboom?
Youtube t9wmWZbr_wQ
 
2022-05-20 2:01:19 PM  
FTFA: "But for antimatter, we've never measured its gravitational attraction at all. In truth, we don't even know whether it falls "down" in a gravitational field the same way normal matter does."

OK, now this may be too simple an explanation for the physics types, but what if matter and antimatter gravitationally repel one another? What if--just after that instant when the four forces (strong, weak, EMF, gravity) were all unified--gravity carved itself off into a separate force and all the matter and antimatter physically shoved away from each other? (So the reason we don't see any antimatter is that it is all in the other "node" of the Universe.) And after that shove, the other three forces broke out of the unified force, and any remaining antimatter that was close to matter got electrically attracted to the overwhelmingly-present matter and got annihilated?
 
2022-05-20 2:06:00 PM  

PirateKing: The universe did not stutter when it said 'Nothing comes back out.'


Technically, "the universe" didn't say that, Einstein's Theory of General Relativity said that. And whether or not he stuttered, I can't tell, but he probably said it with a thick German accent.

We're pretty sure that it still works for black holes, but it seems that a lot of the issues here come from trying to square Einstein with quantum mechanics - itself a well-proven theory - which has certain implications for what goes on in and around black holes.
 
2022-05-20 2:07:19 PM  
I was under the impression we had experimental evidence showing antimatter gravitates the same as 'normal' matter.

Found it. Not sure what level of confidence the physics community gives the results.

If antimatter is affected by gravity exactly the same as normal matter, there shouldn't be any detectable difference between equal-mass matter/antimatter and matter/matter black hole mergers. Any energy release from matter-antimatter annihilation would be contained within the new black hole. Since there is no 'negative mass', the resulting merged black hole would have identical mass to a matter/matter black hole merger.
 
2022-05-20 2:12:22 PM  

Harlee: OK, now this may be too simple an explanation for the physics types, but what if matter and antimatter gravitationally repel one another? What if--just after that instant when the four forces (strong, weak, EMF, gravity) were all unified--gravity carved itself off into a separate force and all the matter and antimatter physically shoved away from each other? (So the reason we don't see any antimatter is that it is all in the other "node" of the Universe.) And after that shove, the other three forces broke out of the unified force, and any remaining antimatter that was close to matter got electrically attracted to the overwhelmingly-present matter and got annihilated?


I'm not convinced that would lead to the matter and antimatter separating to completely different regions of the universe, rather than remaining mixed together in some way, but I guess you'd have to calculate it.
 
2022-05-20 2:20:07 PM  
Goodbye galaxy.
 
2022-05-20 2:24:28 PM  

Ambitwistor: Harlee: OK, now this may be too simple an explanation for the physics types, but what if matter and antimatter gravitationally repel one another? What if--just after that instant when the four forces (strong, weak, EMF, gravity) were all unified--gravity carved itself off into a separate force and all the matter and antimatter physically shoved away from each other? (So the reason we don't see any antimatter is that it is all in the other "node" of the Universe.) And after that shove, the other three forces broke out of the unified force, and any remaining antimatter that was close to matter got electrically attracted to the overwhelmingly-present matter and got annihilated?

I'm not convinced that would lead to the matter and antimatter separating to completely different regions of the universe, rather than remaining mixed together in some way, but I guess you'd have to calculate it.


The key would be that the gravitational force supposedly separated first. The other three forces were still combined (and presumably nonfunctional). So, if gravitational repulsion was unopposed, it would have created two "nodes" and each node, being caught up with the general expansion of space, got moved apart from one another. It explains why there is matter, but no antimatter. The Universe IS symmetrical, overall, but just not locally.
 
2022-05-20 2:45:58 PM  
Well the first problem would be getting enough antimatter to form something larger than a hair, because it would constantly be annihilating itself by the contact it has with atomic matter in the universe as it tries to form. But even if we go with the massive pile of bullshiat required to decide a sphere of antimatter with 50 solar masses could exist (it couldnt, ever), it would never make it through the accretion disk without being turned into the largest non supernova explosion we have ever seen. It would constantly lose mass on the way to the black hole so to the shock of no one who has an ounce of scientific understanding, the "merger" would result in the black hole winning because it was larger than the anti-black hole

I think the more interesting question would be how the explosion would unfold as the anti-black hole was pulled into the accretion disk
 
2022-05-20 3:00:03 PM  
The gravity of a black hole has long since crushed all the electrons down to the nucleus, turning the protons into neutrons and the entire mass into neutronium.

Ergo, all the anti-electrons of anti-matter would have been crushed down to the nucleus and turned all the positrons into neutrons, yes?
 
2022-05-20 3:03:14 PM  

Harlee: Ambitwistor: Harlee: OK, now this may be too simple an explanation for the physics types, but what if matter and antimatter gravitationally repel one another? What if--just after that instant when the four forces (strong, weak, EMF, gravity) were all unified--gravity carved itself off into a separate force and all the matter and antimatter physically shoved away from each other? (So the reason we don't see any antimatter is that it is all in the other "node" of the Universe.) And after that shove, the other three forces broke out of the unified force, and any remaining antimatter that was close to matter got electrically attracted to the overwhelmingly-present matter and got annihilated?

I'm not convinced that would lead to the matter and antimatter separating to completely different regions of the universe, rather than remaining mixed together in some way, but I guess you'd have to calculate it.

The key would be that the gravitational force supposedly separated first. The other three forces were still combined (and presumably nonfunctional). So, if gravitational repulsion was unopposed, it would have created two "nodes" and each node, being caught up with the general expansion of space, got moved apart from one another. It explains why there is matter, but no antimatter. The Universe IS symmetrical, overall, but just not locally.


I'm not sure why it should make a difference whether this happened before a GUT for the other 3 forces underwent spontaneous symmetry breaking - you'd get repulsion between matter and antimatter either way. And again, I'm also not sure whether this would lead to two disconnected "nodes" of matter and antimatter, or just the two intermingled in an expanding way.
 
2022-05-20 3:24:06 PM  

krispos42: The gravity of a black hole has long since crushed all the electrons down to the nucleus, turning the protons into neutrons and the entire mass into neutronium.

Ergo, all the anti-electrons of anti-matter would have been crushed down to the nucleus and turned all the positrons into neutrons, yes?


We don't know. That's the problem when you need to figure out what really strong gravity will do on the really tiniest of scales.

However, anti-electrons (positrons) combine with anti-protons to form anti-neutrons, not neutrons.

A neutron would still annihilate with an anti-neutron. Because a neutron is one up quark and two down quarks, whereas an anti neutron is one anti-up quark and two anti-down quarks.
 
2022-05-20 3:52:35 PM  
"We've only seen black hole mergers where both black holes were made from matter. What would be different if one of them, instead, were antimatter?"

Kimballl Kinnison would have an orgasm.
 
2022-05-20 4:57:19 PM  

Nimbull: [Youtube-video https://www.youtube.com/embed/t9wmWZbr_wQ]


That's all, folks!
 
2022-05-20 6:07:47 PM  

Stibium: Aren't we still trying to figure out if antimatter even has mass, as opposed to negative mass?


Antimatter has the same mass as matter, just a different charge.

As the 2 objects spiral toward each other, it would create the same gravity waves as 2 "normal" black holes.

The difference would be the unimaginable release of energy as the particles annihilate. The mass drops so rapidly that the singularity ceases to exist, and so all that energy would radiate outward. It would be the largest explosion in the universe.

However, given the lack of sufficient antimatter to form a black hole, and the fact that normal matter would fall into it and annihilate, the antimatter would disappear. The release of energy might not be noticeable against the rest of the energy in the universe.
 
2022-05-20 6:12:34 PM  

PirateKing: So even if one of them was a billion solar masses of anti-matter, and the other was a billion solar masses of matter, you'd get the same gravitational wave 'bloop' noise, and a bigger black hole at the end.


The particles would annihilate, the total mass would rapidly fall below that needed to maintain the event horizon, and we'd see a huge release of energy.

Both black holes would cease to exist as the energy radiates into space.
 
2022-05-20 6:19:06 PM  

lifeslammer: But even if we go with the massive pile of bullshiat required to decide a sphere of antimatter with 50 solar masses could exist (it couldnt, ever), it would never make it through the accretion disk without being turned into the largest non supernova explosion we have ever seen. It would constantly lose mass on the way to the black hole so to the shock of no one who has an ounce of scientific understanding, the "merger" would result in the black hole winning because it was larger than the anti-black hole


You're forgetting that as the antimatter hits the "normal" black hole, both will lose mass. The particles annihilate, leaving only energy.

So, both black holes lose mass until they're no longer "black", and we see the annihilation energy radiating outward.

It would be a super-supernova based on the the amount of matter and antimatter involved.
 
2022-05-20 6:28:22 PM  

PirateKing: krispos42: The gravity of a black hole has long since crushed all the electrons down to the nucleus, turning the protons into neutrons and the entire mass into neutronium.

Ergo, all the anti-electrons of anti-matter would have been crushed down to the nucleus and turned all the positrons into neutrons, yes?

We don't know. That's the problem when you need to figure out what really strong gravity will do on the really tiniest of scales.

However, anti-electrons (positrons) combine with anti-protons to form anti-neutrons, not neutrons.

A neutron would still annihilate with an anti-neutron. Because a neutron is one up quark and two down quarks, whereas an anti neutron is one anti-up quark and two anti-down quarks.


I can't tell if you're being facetious or not
 
2022-05-20 7:06:38 PM  
Fark user imageView Full Size
 
2022-05-20 8:45:44 PM  

indy_kid: PirateKing: So even if one of them was a billion solar masses of anti-matter, and the other was a billion solar masses of matter, you'd get the same gravitational wave 'bloop' noise, and a bigger black hole at the end.

The particles would annihilate, the total mass would rapidly fall below that needed to maintain the event horizon, and we'd see a huge release of energy.

Both black holes would cease to exist as the energy radiates into space.


Incorrect.

Why are black holes black again? Because nothing, not even light, can escape the event horizon. So sure, if the 'mass' still counts as mass within the hole, then it might annihilate. In to an equivalent amount of energy, which still has gravitation under general relativity. (See the kugelblitz mention above).

If there's an event horizon, it means exactly that. Events beyond the horizon will never reach you. So your notion that the mass of the black hole could 'fall below' what is needed to maintain the horizon is false, because where does the mass go? It goes into energy, which is then also still inside the black hole.
 
2022-05-20 8:48:47 PM  

krispos42: PirateKing: krispos42: The gravity of a black hole has long since crushed all the electrons down to the nucleus, turning the protons into neutrons and the entire mass into neutronium.

Ergo, all the anti-electrons of anti-matter would have been crushed down to the nucleus and turned all the positrons into neutrons, yes?

We don't know. That's the problem when you need to figure out what really strong gravity will do on the really tiniest of scales.

However, anti-electrons (positrons) combine with anti-protons to form anti-neutrons, not neutrons.

A neutron would still annihilate with an anti-neutron. Because a neutron is one up quark and two down quarks, whereas an anti neutron is one anti-up quark and two anti-down quarks.

I can't tell if you're being facetious or not


I'm really not. Physicists are terrible at naming stuff.

The opposite of an up quark (+2/3)e is an anti-up (-2/3)e quark. The opposite of a down (-1/3)e quark is the anti-down quark(+1/3)e.
 
2022-05-20 9:20:07 PM  
Skeeter Davis - The End of the World (HD)
Youtube DGLPvnbryGU
 
2022-05-20 9:38:22 PM  

PirateKing: indy_kid: PirateKing: So even if one of them was a billion solar masses of anti-matter, and the other was a billion solar masses of matter, you'd get the same gravitational wave 'bloop' noise, and a bigger black hole at the end.

The particles would annihilate, the total mass would rapidly fall below that needed to maintain the event horizon, and we'd see a huge release of energy.

Both black holes would cease to exist as the energy radiates into space.

Incorrect.

Why are black holes black again? Because nothing, not even light, can escape the event horizon. So sure, if the 'mass' still counts as mass within the hole, then it might annihilate. In to an equivalent amount of energy, which still has gravitation under general relativity. (See the kugelblitz mention above).

If there's an event horizon, it means exactly that. Events beyond the horizon will never reach you. So your notion that the mass of the black hole could 'fall below' what is needed to maintain the horizon is false, because where does the mass go? It goes into energy, which is then also still inside the black hole.


The energy from matter-antimatter annihilation cannot exceed C, so it's stuck inside the singularity. There would be no loss of mass, because the energy released is equivalent to matter (E=MC2). The equation works for whichever variable you solve for. The mass equivalent of the energy would be E/C2=M. There would be no detectable difference between matter-matter black hole mergers and matter-antimatter black hole mergers because of this.
 
2022-05-21 9:28:35 AM  

PirateKing: krispos42: PirateKing: krispos42: The gravity of a black hole has long since crushed all the electrons down to the nucleus, turning the protons into neutrons and the entire mass into neutronium.

Ergo, all the anti-electrons of anti-matter would have been crushed down to the nucleus and turned all the positrons into neutrons, yes?

We don't know. That's the problem when you need to figure out what really strong gravity will do on the really tiniest of scales.

However, anti-electrons (positrons) combine with anti-protons to form anti-neutrons, not neutrons.

A neutron would still annihilate with an anti-neutron. Because a neutron is one up quark and two down quarks, whereas an anti neutron is one anti-up quark and two anti-down quarks.

I can't tell if you're being facetious or not

I'm really not. Physicists are terrible at naming stuff.

The opposite of an up quark (+2/3)e is an anti-up (-2/3)e quark. The opposite of a down (-1/3)e quark is the anti-down quark(+1/3)e.


Huh.  Okay, I guess.  I've never heard of an anti-neutron, just positrons and anti-protons.  I always had figured neutrons were just neutrons.
 
2022-05-21 9:43:51 AM  

Wenchmaster: I was under the impression we had experimental evidence showing antimatter gravitates the same as 'normal' matter.

Found it. Not sure what level of confidence the physics community gives the results.

If antimatter is affected by gravity exactly the same as normal matter, there shouldn't be any detectable difference between equal-mass matter/antimatter and matter/matter black hole mergers. Any energy release from matter-antimatter annihilation would be contained within the new black hole. Since there is no 'negative mass', the resulting merged black hole would have identical mass to a matter/matter black hole merger.


It's constructed by the same quarks that construct normal matter.  It has has a different combination of them.  Since these quarks are subject to gravity via their connection to the Higgs... there is absolutely no reason anitmatter would not behave normally under gravity.

The real question comes down to what is behind the event horizon.  Either it's a singularity, in which case the merger of a matter and antimatter based pair of black holes would do absolutely nothing unexpected, OR it's some kind of boson condensate (think neutron star, but crushed down to quark levels)... in which case it does... absolutely nothing unexpected.
 
2022-05-21 11:55:11 AM  

PirateKing: indy_kid: PirateKing: So even if one of them was a billion solar masses of anti-matter, and the other was a billion solar masses of matter, you'd get the same gravitational wave 'bloop' noise, and a bigger black hole at the end.

The particles would annihilate, the total mass would rapidly fall below that needed to maintain the event horizon, and we'd see a huge release of energy.

Both black holes would cease to exist as the energy radiates into space.

Incorrect.

Why are black holes black again? Because nothing, not even light, can escape the event horizon. So sure, if the 'mass' still counts as mass within the hole, then it might annihilate. In to an equivalent amount of energy, which still has gravitation under general relativity. (See the kugelblitz mention above).

If there's an event horizon, it means exactly that. Events beyond the horizon will never reach you. So your notion that the mass of the black hole could 'fall below' what is needed to maintain the horizon is false, because where does the mass go? It goes into energy, which is then also still inside the black hole.


Google "Hawking radiation".

Black holes can actually lose mass due to quantum effects.  Sometimes a particle pair forms at the very border of the event horizon, and half of it manages to pop into existence on the outside of the event horizon and with the required momentum to escape.

It's a very slow process, you wouldn't expect black holes to finish evaporating until the rest of the universe has decayed into darkness, but the math says it's happening.
 
2022-05-21 1:02:30 PM  

Unsung_Hero: PirateKing: indy_kid: PirateKing: So even if one of them was a billion solar masses of anti-matter, and the other was a billion solar masses of matter, you'd get the same gravitational wave 'bloop' noise, and a bigger black hole at the end.

The particles would annihilate, the total mass would rapidly fall below that needed to maintain the event horizon, and we'd see a huge release of energy.

Both black holes would cease to exist as the energy radiates into space.

Incorrect.

Why are black holes black again? Because nothing, not even light, can escape the event horizon. So sure, if the 'mass' still counts as mass within the hole, then it might annihilate. In to an equivalent amount of energy, which still has gravitation under general relativity. (See the kugelblitz mention above).

If there's an event horizon, it means exactly that. Events beyond the horizon will never reach you. So your notion that the mass of the black hole could 'fall below' what is needed to maintain the horizon is false, because where does the mass go? It goes into energy, which is then also still inside the black hole.

Google "Hawking radiation".

Black holes can actually lose mass due to quantum effects.  Sometimes a particle pair forms at the very border of the event horizon, and half of it manages to pop into existence on the outside of the event horizon and with the required momentum to escape.

It's a very slow process, you wouldn't expect black holes to finish evaporating until the rest of the universe has decayed into darkness, but the math says it's happening.


Yes, but Hawking radiation is generated outside the horizon, not inside. It does use up some of the mass of the black hole, at a rate inversely proportional to the mass. So the bigger they are, the slower they radiate away.
 
2022-05-21 1:35:38 PM  

PirateKing: Hawking radiation is generated outside the horizon, not inside. It does use up some of the mass of the black hole, at a rate inversely proportional to the mass. So the bigger they are, the slower they radiate away.


I am not sure if you have changed your mind or if you somehow think this is compatible with your post that "So your notion that the mass of the black hole could 'fall below' what is needed to maintain the horizon is false, because where does the mass go? It goes into energy, which is then also still inside the black hole."
 
2022-05-21 2:27:24 PM  

Unsung_Hero: PirateKing: Hawking radiation is generated outside the horizon, not inside. It does use up some of the mass of the black hole, at a rate inversely proportional to the mass. So the bigger they are, the slower they radiate away.

I am not sure if you have changed your mind or if you somehow think this is compatible with your post that "So your notion that the mass of the black hole could 'fall below' what is needed to maintain the horizon is false, because where does the mass go? It goes into energy, which is then also still inside the black hole."


Yes, and? The Hawking radiation is emitted outside the horizon. It carries away some of the mass of the black hole with it. This is the only known mechanism for a horizon to shrink. In black hole mergers, some of the mass/energy is radiated away in gravity waves, but the resulting hole will be larger than either of the two individual holes.

It's tempting to think that because there's a minimum limit for a collapsing star to form a horizon that there must be some limit below which the horizon will 'go away'. And that limit is zero. Once formed, the horizon  will always have an escape velocity >c, until the distance needed to travel is too small to be meaningful without quantum gravity.

It's not believed there will never be a point where the mass falls below a point such that there's not a horizon anymore, until it's too small for GR to make accurate predictions. This is part of the issue without a working theory of quantum gravity. We just don't know what happens on scales that small and gravity that big.

What we think happens, according to Hawking, is that the rate of radiation is inversely proportional to the mass of the black hole, such that the bigger the hole the slower it radiates. So as it shrinks, over timescales so big that the exponents have exponents, the horizon gets ever so smaller, and the rate of evaporation grows. Eventually, it will evaporate away to nothing and the final energy left will radiate away, but all of this happens above the shrinking horizon. Note that the 'rapid evaporation' of the final instant is going to look a lot like a large explosion.

So the 'hole' is always there until it's not, according to Hawking. There are some liberties taken because we don't have a theory of quantum gravity that works on the subatomic scales. What does an event horizon look like when it's too small for anything to cross it? What does gravity look like when the distance between two masses is less than the quantum wavelengths of their components?

The point of all of this is that even when matter and antimatter annihilate, they annihilate into good old-fashioned EM radiation. So if one black hole was made of antimatter, and the other matter, even if whatever is at the core, be it singularity or degenerate matter, were to annihilate, it's just more light inside a black hole.

I suspect that it wouldn't look any different than any other black hole merger, before or after.
 
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