Could you kill an ordinary black hole by feeding it antimatter?

Asked by ETpro (34605) July 8th, 2013

I know what happens when matter and antimatter come together under more normal conditions. But does the same thing happen in areas of gravitational collapse? We can’t observe the inner workings of particle physics inside a black hole. But I presume that particle physicists can calculate what we think would happen. What do those calculations suggest?

It’s hard not to find black holes fascinating. So I’ve been accumulating a series of questions about them over the years, and now it’s time to ask them in the Black Hole Series. Previous entries included:
1  —  “Can a black hole overeat?”
2  —  “How big is your average black hole?”
3  —  “What happens when a black hole evaporates?”
4  —  “Would an ordinary black hole attract antimatter?”

Also, @mattbrowne asked What exactly happens when a (hypothetical) antimatter black hole merges with a ‘normal’ black hole? shortly before I arrived here. That excellent question deserves to be part of the series. Feel free to add any other notable black hole questions from whatever date.

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I’m not a astrophysicist, but I think you would need an equal weight of antimatter to annihilate the matter black hole.
-1+1 = 0

Y E S

Perhaps if you fed it a white hole

Lightlyseared (34653)

@Tropical_Willie I get the -1 +1 = 0 but I truly wonder if the same holds true within complete gravitational collapse. So much of our ordinary understanding of particle physics has to do with space-time; and space-time either breaks down in such massive gravitational wells.

@Lightlyseared If there are while hold, shouldn’t we see them?

ETpro (34605)

No, the antimatter will not kill the black hole, according to the no-hair theorem.

This arises from the fact that both matter and antimatter have equal, positive mass. So, when you are adding antimatter to the black hole, you are still increasing the mass of the black hole.

When antimatter annihilates normal matter, it does convert a large amount of mass to pure energy (in the form of photons, gluons, etc.). As far as the black hole is concerned, however, energy=mass. So, the black hole does not lose any weight, and simply gains more weight from being fed antimatter.

PhiNotPi (12681)

@PhiNotPi I see that perfectly. Great explanation. Thanks.

ETpro (34605)

I do not think that energy is effected BY gravity or has an effect ON gravity. Steven Hawking has theorized that Hawking radiation could cause a black hole to decrease in size until it finally hit critical mass and the gravitational field could no longer hold back that energy. This would cause a massive release of various types of energy ranging across the spectrum. So, yes. You can “kill” a black hole, and it’s death throes would be spectacular.

However, this is assuming that quantum mechanics doesn’t rear it’s ugly head and f**k everything up. If it does, then all bets are off.

@Mr_Paradox I can grasp only the fundamentals of Hawking’s work on Hawking Radiation, and the math of it is beyond my reach. But I can tell you that he factors in relativistic maths and quantum mechanics. Still, we have yet to observe Hawking Radiation so the idea is really a well supported hypothesis, not a theory.

ETpro (34605)

The point I was trying to make still stands though, since antimatter and matter annihilate when they touch energy is released. Energy is free from the constraints of gravity. So, the gravitational force of the black hole decreases. All that is needed is antimatter. Hawking Radiation is just the most promising explanation of how that would work.

@Mr_Paradox What makes you think that gravity does not affect energy?

ETpro (34605)

@Mr_Paradox Gravity does affect energy. Neither energy nor mass can exist independently of particles.

From the wiki: “Since energy and momentum must be conserved, the particles are simply transformed into new particles. They do not disappear from existence. ”

This chart shows how photons are released from an electron-positron annihilation. These released photons are affected by gravity.

PhiNotPi (12681)

This is so far above my depth that it is no wonder that I am confused. It is my understanding that particles are an amalgamation of waves and fields and therefore do not literally exist, and that gravity is the curvature of space and time caused by mass. I am sure that someone here will correct my faulty notions.

Bill1939 (10772)

@Bill1939 Yes, yes. Gravity isn’t really gravity. It is the warpage of spacetime, much like having a bowling ball sitting on a tightly stretched sheet of latex rubber would warp the sheet. Not the mind blowing part. Roll a marble in a big decreasing spiral around the bowling ball, and it will eventually fall into the deepest part of the depression produced by the bowling ball. Why? Gravity (which mind you doesn’t really exist) pulls it down there. :-)

ETpro (34605)