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I really want primordial black holes to turn out to be the missing antimatter from the Big Bang, but I don’t think that could ever be tested. And of course a me

I really want primordial black holes to turn out to be the missing antimatter from the Big Bang, but I don’t think that could ever be tested. And of course a mechanism for this would probably need new physics since antimatter interacts the same as normal matter wrt gravity.

deepsun 2y ago
When I asked similar questions physicists, turns out all of them were thought off and tested long time ago. E.g. small black holes would still cause detectable and attributable radiation.
stainablesteel 2y ago
it sounds a lot like it now that i read this, large dispersed amounts of antimatter that apparently doesn't give off light yet has massive gravitational pull
- nullserver 2y ago
  https://youtu.be/qy8MdewY_TY?si=NVZzWJSFXl4EATRK https://youtu.be/qy8MdewY_TY?si=NVZzWJSFXl4EATRK Good video on topic
- ccgreg 2y ago
  Antimatter has the same electrodynamic properties as matter.
pfdietz 2y ago
There were suggestions that the antimatter-matter asymmetry is because antimatter was preferentially segregated into a dense phase of hadronic matter, like quark matter nuggets. This would be interesting because if such nuggets could be found and captured, they'd be a potential source of energy by annihilation with ordinary matter.
- exe34 2y ago
  Spicy nuggets.
- NegativeLatency 2y ago
  > preferentially segregated into a dense phase of hadronic matter Sounds interesting, where can I read more theories about this?
  - pfdietz 2y ago
    Here's a recent (2021) paper on the idea: https://arxiv.org/abs/2105.08719 https://arxiv.org/abs/2105.08719 It has the nice feature of explaining why the density of baryons and the density of dark matter are not too different. Naively, there's no reason to expect the two to be anywhere close to each other. It also offers an explanation for the observed matter-antimatter asymmetry in the universe. Don't believe any theory until it's been well tested.
deleted 2y ago
[deleted]
dreamcompiler 2y ago
What happens when an antimatter black hole collides with a matter black hole? We'd see gravitational waves but no photons, right? Would the grav waves reflect the tremendous energy release somehow?
- azernik 2y ago
  An alternate explanation to the no-hair one: In a black hole, all you see from the outside is total mass. This is actually mass-energy - a release of energy inside the black hole doesn't change the total mass-energy inside.
- at_a_remove 2y ago
  No. The "no hair theorem" states that black holes preserve exactly three numbers: mass, charge, and angular momentum. Baryon number, lepton number (as you would see in antimatter) are not conserved, the information is lost. And, no, antimatter does not have negative mass, in any of the three contexts (mass-energy equivalence, inertia, and gravitational). Therefore, a black hole fed entirely by antimatter would be indistinguishable from a black hole fed entirely by the equivalent matter.
  - deepsun 2y ago
    But it's charge would be negated, since charge is one of the parameters, no? Not sure it affects anything tho.
    - at_a_remove 2y ago
      Not necessarily. You could load up one black hole with electrons and the other black hole with anti-protons ... both would have negative charge, -Q ... but the latter would have a much greater mass, since anti-protons are much heavier than electrons, despite having equal charges. "Antimatter" is really only "anti" in a few respects. First, the lepton or baryon number has the sign flipped. An electron has a positive lepton number; a positron would have a negative lepton number. The charges are also flipped, where applicable (anti-neutrons still have a charge of zero). Isospin is flipped; spin is not. Mass is not, in three ways. First, if you converted an anti-proton into pure energy (ignoring charge conservation, et al), it is the same energy as you would get out of a proton. Second, an anti-proton exerts the same gravitational pull as a proton. A world of anti-matter would cause you to fall toward it the same way the Earth would. Third, a force exerted on an antiproton causes it to accelerate along the same vector as the force, so the inertia is the same as regular matter. People have theorized, myself included, on what some kind of matter where mass was negative (let's dub it nega-matter) would look like, which is to say that a force pushing it away would contrarily draw it toward you. You can simulate it in particle life, likely, but what would happens is that all of the nega-electrons would feel electrostatic repulsion and therefore clump together, as would all of the nega-protons. These two lumps of enormous charge (we just don't get that in real life, electrostatics are dozens of orders of magnitude more powerful than gravity) would create an "attractive" field between them of nearly incalculable strength and, because they would move opposite to the vector of the force, promptly zoom away at many nines of the speed of light. In short, they would sort themselves out and fly away to distant corners of the universe with great haste.

deepsun 2y ago

When I asked similar questions physicists, turns out all of them were thought off and tested long time ago. E.g. small black holes would still cause detectable and attributable radiation.

stainablesteel 2y ago

it sounds a lot like it now that i read this, large dispersed amounts of antimatter that apparently doesn't give off light yet has massive gravitational pull

nullserver 2y ago
https://youtu.be/qy8MdewY_TY?si=NVZzWJSFXl4EATRK https://youtu.be/qy8MdewY_TY?si=NVZzWJSFXl4EATRK Good video on topic
ccgreg 2y ago
Antimatter has the same electrodynamic properties as matter.

pfdietz 2y ago

There were suggestions that the antimatter-matter asymmetry is because antimatter was preferentially segregated into a dense phase of hadronic matter, like quark matter nuggets. This would be interesting because if such nuggets could be found and captured, they'd be a potential source of energy by annihilation with ordinary matter.

exe34 2y ago
Spicy nuggets.
NegativeLatency 2y ago
> preferentially segregated into a dense phase of hadronic matter Sounds interesting, where can I read more theories about this?
- pfdietz 2y ago
  Here's a recent (2021) paper on the idea: https://arxiv.org/abs/2105.08719 https://arxiv.org/abs/2105.08719 It has the nice feature of explaining why the density of baryons and the density of dark matter are not too different. Naively, there's no reason to expect the two to be anywhere close to each other. It also offers an explanation for the observed matter-antimatter asymmetry in the universe. Don't believe any theory until it's been well tested.

deleted 2y ago

[deleted]

dreamcompiler 2y ago

What happens when an antimatter black hole collides with a matter black hole? We'd see gravitational waves but no photons, right? Would the grav waves reflect the tremendous energy release somehow?

azernik 2y ago
An alternate explanation to the no-hair one: In a black hole, all you see from the outside is total mass. This is actually mass-energy - a release of energy inside the black hole doesn't change the total mass-energy inside.
at_a_remove 2y ago
No. The "no hair theorem" states that black holes preserve exactly three numbers: mass, charge, and angular momentum. Baryon number, lepton number (as you would see in antimatter) are not conserved, the information is lost. And, no, antimatter does not have negative mass, in any of the three contexts (mass-energy equivalence, inertia, and gravitational). Therefore, a black hole fed entirely by antimatter would be indistinguishable from a black hole fed entirely by the equivalent matter.
- deepsun 2y ago
  But it's charge would be negated, since charge is one of the parameters, no? Not sure it affects anything tho.
  - at_a_remove 2y ago
    Not necessarily. You could load up one black hole with electrons and the other black hole with anti-protons ... both would have negative charge, -Q ... but the latter would have a much greater mass, since anti-protons are much heavier than electrons, despite having equal charges. "Antimatter" is really only "anti" in a few respects. First, the lepton or baryon number has the sign flipped. An electron has a positive lepton number; a positron would have a negative lepton number. The charges are also flipped, where applicable (anti-neutrons still have a charge of zero). Isospin is flipped; spin is not. Mass is not, in three ways. First, if you converted an anti-proton into pure energy (ignoring charge conservation, et al), it is the same energy as you would get out of a proton. Second, an anti-proton exerts the same gravitational pull as a proton. A world of anti-matter would cause you to fall toward it the same way the Earth would. Third, a force exerted on an antiproton causes it to accelerate along the same vector as the force, so the inertia is the same as regular matter. People have theorized, myself included, on what some kind of matter where mass was negative (let's dub it nega-matter) would look like, which is to say that a force pushing it away would contrarily draw it toward you. You can simulate it in particle life, likely, but what would happens is that all of the nega-electrons would feel electrostatic repulsion and therefore clump together, as would all of the nega-protons. These two lumps of enormous charge (we just don't get that in real life, electrostatics are dozens of orders of magnitude more powerful than gravity) would create an "attractive" field between them of nearly incalculable strength and, because they would move opposite to the vector of the force, promptly zoom away at many nines of the speed of light. In short, they would sort themselves out and fly away to distant corners of the universe with great haste.