Can you have an antimatter black hole?

[Philjhinson]

Sorry for a bit of a sci fi question but are anti matter black holes likely, presumably they would need to come from whole antimatter stars in antimatter galaxies? otherwise they would already have destroyed themselves?

 

[Chronos]

A black hole is a black hole is a black hole. An anti matter black hole would be no different than a black hole formed from stars, hydrogen clouds or abandoned ET spaceship engines. See here for discussion https://sciencequestionswithchris.wordpress.com/2014/05/16/how-can-you-tell-a-black-hole-made-out-of-antimatter-from-a-black-hole-made-out-of-matter/

 

[2milehi]

It has yet to be proven that matter and anti-matter are gravitational attracted to each other.

 

[Vanadium 50]

It has yet to be proven that matter and anti-matter are gravitational attracted to each other.

If energy is conserved, Pound-Rebka proves that. Even if energy is not conserved, this would show up in Eotvos-type experiments. Furthermore, the same theory that gives you black holes predicts that matter and antimatter fall at the same rate.

 

[ViperSRT3g]

This makes me wonder if the two types of matter have any effect on each other upon falling into a black hole. But a black hole will still pull in the things around it as it is a gravitational phenomenon.

 

[phinds]

This makes me wonder if the two types of matter have any effect on each other upon falling into a black hole. But a black hole will still pull in the things around it as it is a gravitational phenomenon.

Seems to me that if a an electron and a positron annihilate outside the event horizon, a resulting photon might be pointed away from the black hole in which case the resulting addition to the mass of the black hole would be less by the mass equivalent of the energy of the escaping photon than if the two particles had just fallen in.

 

[Andrekosmos]

Yes it is probable and Dark Matter Black Holes too.

http://www.scientificamerican.com/article/dark-matter-black-holes-destroying-pulsars/

 

[Chronos]

If Dark matter is truly collisionless, as is believed, it has no way to shed kinetic energy - meaning little, if any of it can be captured by black holes

 

[phinds]

Yes it is probable and Dark Matter Black Holes too.

http://www.scientificamerican.com/article/dark-matter-black-holes-destroying-pulsars/

There is no such thing as a "dark matter black hole". If dark matter goes into a black hole, it's still just a black hole.

 

[Andrekosmos]

I forgot to mention these are just claims made by theorists, also quantum black holes could be the constitutes of dark matter and is being considered a candidate.

http://www.dailymail.co.uk/sciencet...-substance-lurking-universes-mass-hiding.html

 

[phinds]

I forgot to mention these are just claims made by theorists, also quantum black holes could be the constitutes of dark matter and is being considered a candidate.

http://www.dailymail.co.uk/sciencet...-substance-lurking-universes-mass-hiding.html

The problem w/ tiny black holes is that if Hawking Radiation does exist, then tiny black holes last for less time than my last slice of pizza and there would not be any around even if they HAD formed in the early universe.

 

[ShayanJ]

The problem w/ tiny black holes is that if Hawking Radiation does exist, then tiny black holes last for less time than my last slice of pizza and there would not be any around even if they HAD formed in the early universe.

That's not a problem with tiny black holes themselves, but a problem with their observation!

 

[phinds]

That's not a problem with tiny black holes themselves, but a problem with their observation!

I'm not following you. It seems to me the issue is whether they exist for any amount of time even if they come into existence. Hawking Radiation says no they don't. How do you observe something that doesn't exist? Yeah, I guess that would be a problem.

 

[ShayanJ]

I'm not following you. It seems to me the issue is whether they exist for any amount of time even if they come into existence. Hawking Radiation says no they don't. How do you observe something that doesn't exist? Yeah, I guess that would be a problem.

The point I'm trying to make, is that this argument is different from the argument against e.g. the existence of white holes corresponding to collapsing stars. Because of the latter, we don't search for white holes. But about the former, we should note that there are(theoretically) processes that result in the creation of microblackholes within our reach. We may actually be able to observe such black holes in LHC.

 

[phinds]

OK, now I see what you are saying. This sort of sidetracked the discussion about whether or not quantum black holes could be all or part of dark matter. That is, your statement really had nothing to do with that topic, which is why it confused me.

 

[Quds Akbar]

According to the website I added the link to on the bottom there is no difference:
"...there is no way to distinguish an antimatter black hole from a regular-matter black hole. In fact, there is no difference between an antimatter black hole and a regular-matter black hole if they have the same mass, charge, and angular-momentum.:
https://sciencequestionswithchris.wordpress.com/2014/05/16/how-can-you-tell-a-black-hole-made-out-of-antimatter-from-a-black-hole-made-out-of-matter/

 

[websterling]

If Dark matter is truly collisionless, as is believed, it has no way to shed kinetic energy - meaning little, if any of it can be captured by black holes

Since dark matter is gravitationally attractive wouldn't it feel the pull of a black hole? And if it crossed the event horizon wouldn't it be unable to escape and considered as captured?

 

[phinds]

Since dark matter is gravitationally attractive wouldn't it feel the pull of a black hole? And if it crossed the event horizon wouldn't it be unable to escape and considered as captured?

Yes and yes, but the point being made is that dark matter is much less likely to be captured in an accretion disk because it doesn't bump into anything so if it is not captured by a black hole as it passes by, it's going to just keep on going, whereas normal matter would interact with any accretion disk and thus slow down and later be captured.

 

[Chronos]

For an explanation by a genuine astrophysicist see here: http://curious.astro.cornell.edu/ph...t-dark-matter-fall-into-a-black-hole-advanced. For a more detaile account see;http://arxiv.org/abs/0802.2041, Dark Matter Accretion Into Supermassive Black Holes.http://arxiv.org/abs/0802.2041