Matter and anti-matter blackholes combine - What happens?

Question

Situation: There are two blackholes; one that was formed completely of matter; and on that was completely formed of anti-matter. Do they cancel each other out and form energy or just make a bigger blackhole? (Maybe I just shouldn't have started reading science fiction again!)

Answer 1

OK.
Let's imagine one black hole (A) that was made from normal matter (positive protons, neutral neutrons and negative electrons) -- at least, when the matter crossed the event horizon.

Black hole B was made from anti-matter (negative anti-protons, neutral anti-neutrons, positive anti-electrons a.k.a. positrons).

I've made the black holes large enough that atoms can survive to the event horizon (the tidal effect of a large black hole at its event horizon is less than that of a small black hole at its event horizon... go figure).

Once inside, the atom would be divided into its constituents then into the quarks that formed them.

A proton is made of two "up" and one "down" quarks.
An anti proton is made of two "anti-up" and one "anti-down" quarks.

Same idea for neutrons and electrons (and their anti-partners).

The quarks themselves could be crunched down to their constituents (if they have any) such as the postulated "preons" and, of course, anti-preons (if they exist at all).

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However, the matter would be inexorably attracted towards the centre of the black hole (where the tidal effects get stronger and stronger -- maybe even tearing the preons apart).

When the event horizons get in contact, the black hole will coalesce into one bigger black hole (the matter and anti-matter are not yet in contact).

It is unclear how soon after the merging will the two "singularities" become one, if at all.

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Back to our matter vs anti-matter thing.

When the protons and anti-protons meet, the down and anti-down quarks are more attracted to each other than they are to their (former) up partners. Together, they form a photon (preons and anti-preons also form photons and other leptons).

Here's the interesting question: the energy that was present as mass is transformed into radiation (probably very energetic photons). If all that mass disappears, is the black hole still a black hole?

On the other hand, we know (from Relativity and from Mercury's advancing perihelion) that a high "density" of radiation does affect gravity the same as mass. Then the black hole is still a black hole even though there is no more "matter" in it.

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I suspect that all kinds of things could happen but we will never know as the information would not escape the black hole.

Answer 2

Nothing. They would form a big black hole.

To physics the sign of the charge of a lepton does not matter. Well, almost. It matters for some cross sections involving neutrinos and that matters for the early universe where more matter than anti-matter was left at the end of the day. And that matters to us because we are not made of light and neutrinos.

But in a black hole it does not matter. By the time matter disappears below the event horizon, the weak interaction, which is the only thing that distinguishes matter and anti-matter, has nothing to say any more. Near the singularity electromagnetic force, strong force and weak force vanish and become united with gravity to THE FORCE. And THE FORCE makes no distinction between matter and anti-matter.

So while you are asking a rather interesting question, the answer is rather boring.

:-)

Answer 3

To help you out: http://en.wikipedia.org/wiki/Blackholes
and
http://en.wikipedia.org/wiki/Black_hole_information_paradox

Because black holes are phenomena where gravitation is so strong nothing can escape, it makes no difference if they're formed from matter or anti-matter, they still end up the same. That's basically what the "Black hole information paradox" states.
But something does happen with two black holes brought together: http://www.abc.net.au/science/news/stories/s637467.htm

And this actually happened: http://science.nasa.gov/headlines/y2002/20nov_2bh.htm

A little research goes a long way...

Answer 4

A black hole has only three observable properties: mass, angular momentum, and electrical charge. Since antimatter has positive mass, the information as to whether a black hole is formed from collapsed matter or antimatter is lost after its formation.

Answer 5

I don't know much about blackhole and physics, but what I know from nuclear chemistry is that positron (aka positive electron because it's like electron, except that it's positive in charge) is an anti-matter. It got that name because when it combines with an electron, the two "particles" destroy each other and energy remains.

Answer 6

You would never know because the intense gravitational well would keep all bits and pieces of any reaction from escaping. If light can't get out of a black hole, then neither will particles that move slower than light.

Answer 7

Anti-Matter does exist. but not in mass quantity.

If the two were to actually meet, hypothetically they would cancel each other out.

Answer 8

There are no black holes made of anti matter.

Answer 9

what does it matter?

haha ha!

Antimatter is fictional.