Posted on by Fraser Cain

What if a Black Hole Met an Antimatter Black Hole?

Would shooting a black hole into an antimatter black hole destroy them both?

I’ve wondered out loud how it might be possible to destroy a black hole because I talk to myself and sometimes there’s a camera watching.

I’ve suggested a bunch of crazy ideas, like blasting it with rockets, shooting lasers at it, smashing planets into it. Nothing would work, everything would just make it bigger and angrier.

Turns out the only way to defeat a black hole is to sit on your hands and wait for it to evaporate. That’s not really helpful if you’re getting pulled into the black hole, and have sense of immediacy about it.

I mentioned one idea, antimatter, and dismissed it as just another hopeless and pointless way to enflame this galactic monstrosity.

But wait, you say, isn’t antimatter the opposite of regular matter. If you add a positive number and a negative number together, don’t they just cancel each other out?

Why won’t that green blooded pointy-eared hobgoblin of a science officer back me on this one?

Why can’t you just pump antimatter in to cancel out the regular matter of the black hole and cut a path to escape?

Antimatter is exactly the same as regular matter, except everything is backwards. Electrical charges, spin directions, and configuration of all the sub-particles that make it up. It’s all backwards.

Everything is opposite, except for mass. An anti-electron has the exact same amount of mass as electron.

Here’s the part you care about. When equal amounts of matter and antimatter collide, they are annihilated. But not disappeared or canceled out. They’re convert into pure energy.

As Einstein explained to us, mass and energy are just different aspects of the same thing. You can turn mass into energy, and you can turn energy into mass.

Black holes turn everything, both matter and energy, into more black hole.

Imagine a regular flavor and an antimatter flavor black hole with the same mass slamming together. The two would be annihilated and turn into pure energy.

Of course, the gravity of a black hole is so immense that nothing, not even light can escape. So all energy would just be turned instantaneously into more black hole. Want more black hole? Put things into the black hole.

If these two objects came together, you’d end up with a black hole with twice the mass that you had before.

Also, creating an antimatter black hole would be expensive. Antimatter is produced in particle accelerators, protons are accelerated in an enormous ring, pushed to nearly the speed of light, and then smashed into each other’s faces.

The collective momentum of the particle is converted into mass using Einstein’s famous e=mc2 calculation. Each collision creates a tiny handful of particles that could be collected and contained in a magnetic field to hold them in place and keep them from being annihilated.

According to NASA, a single gram of antihydrogen would cost about $62.5 trillion to create, the most expensive material we could possibly make on Earth.

It could be more expensive than that. It’s possible that the Large Hadron Collider is capable of creating microscopic black holes, although none have been created yet. If physicists could work out that math, then you could create microscopic antimatter black holes by smashing together anti-hydrogen particles, and the costs involved would dwarf the production of antimatter itself.

The bottom line is: If a regular black hole and an antimatter black hole got black-hole-married in space, they wouldn’t vanish.

Feeding in antimatter won’t do any good, it’s just like regular matter or energy. It only makes the black hole more massive. That should save you some money in wasteful antimatter production.

You’re welcome. And I’m sorry. Farewell traveller, your antimatter stores won’t save you now.

What part about black holes still amaze and confuse you? Let us know in the comments below and we’ll queue up some answers for future shows.

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24 Replies to “What if a Black Hole Met an Antimatter Black Hole?”

  1. Yeap. Antimatter is an electrical difference, not, mmm, the inertial or “mass” aspect (though it would transform to gamma rays and things, it would will have gravitational awareness.)

    However there is something called “negative matter” which is so far purely theoretical…. that would (cough) evaporate the mass/inertia quality of matter.

  2. i don`t know where you got the idea of an anti-black-hole…such thing simply doesn`t exist…maybe you tought about neotron-stars , which in theory could exist on the other side of the matter as anti-neutro-stars. In black holes, mater is broken down to a new state of being, wnere we cannot talk about matter or antimater anymore. Nobody knows for sure what they are made of, but it seems that “god-particles” (proved by LHC) are the only thing contained in, and so the size of a small black hole is a zillion times smaller than the biggest neutron-star. You cannot talk about anti-god-particles, as they are only mass, no charge or rotation…so no such thing as an anti-black-hole…

    1. The universe was according to the big bang theory made almost equal matter and antimatter. There was slightly more matter then antimatter and thats what the observable universe is made of. Probably. Its theoretically possible that regions of the universe contains antimatter, even anti-stars and anti-galaxies. These would probably make black holes just as normal matter stars and galaxies does. Now if these matte and antimatter regions of space collided there is a tiny possibility that normal and anti black holes might collide.

      But sending an antimatter-producing machine to orbit a normal matter black hole, bombarding it with its antimatter, is quite unrealistic in so many ways.

    2. Yes, what are black holes made of? All that matter entering and nothing coming out. I don’t know what particles there could be but the composition would be made of everything there is. We can say that they are not in a gas state and liquid needs just the right conditions. So “Black Holes” must be solid objects. If not there must be a new state of matter denser than a solid. Time to stop referring to these things as “Holes”. You can say we don’t see what’s inside but we know by the mass how much is inside. They are collapsed but we don’t know to what. Dense plasma? It just seems easier to think of these things as a solid object rather than a hole. A hole is nothing. Not the center of a Galaxy. How about “Black Galactic Core”.

      1. When sun like stars go supernova the core remains will become a white dwarf. They are not liquid, solid, gas or plasma. They are “electron degenerate matter” an extremly compressed and exotic form of solid where atoms are packed extremely much closer then in a normal solid. This type of matter behaves very strange.

        Bigger stars may become neutron stars. They are also a type of degenerate matter, but compressed extremely much more then white dwarfs. Electrons are combined with protons to form neutrons.

        Even bigger stars may become black holes. Its often assumed that atoms get packed much denser then in neutron stars. Maybe its in another type of degenerate matter state.

      2. When neutrons collapse they break down into extremely high energy quark type matter. A black hole should be a mixture of this ultra relativistic quark type matter and a small percentage light. Both produce produce a pressure equal to (density)(c^2)/3. This enormous pressure describes a gas. It can be considered a dense plasma. The size of this finite size object can be calculated using the virial equation. Its not a singularity and hole is not the best word.

      4. Black holes as solids compressing? Yes, compressed until they explode; As in Big Bang. It may take a lot of mass as in the mass of our universe. And in an expanding Universe, it may take a lot of time and space for all that matter to meet up. And not necessarily all from this universe. But we know gravity is hard at work.

  3. Can dark matter form black holes? After all, it has mass and interacts gravitationally. In fact, that’s the only way it interacts.

    1. In principle, yes. In practice – sort of.

      A stellar black hole in a galactic orbit will sweep up dark matter. A sufficiently massive one (which at this point in history probably means all of them, not counting hypothetical low mass primordial black holes) will collect dark matter faster than it emits Hawking radiation. As it does so it will gain mass and sink toward the galaxy’s core, eventually merging with the central black hole.

      I think in the very distant future essentially all gravitationally bound dark matter (that is, all of it within galaxies, clusters etc.) will be captured long before the largest black holes evaporate but I haven’t seen anyone run the numbers. Anything NOT gravitationally bound (dark matter or not) will have been diluted to approximately zero by expansion.

  4. What happens when a black hole slightly above the Chandrasekhar limit slowly evaporates to cross the limit? Would it explode or reveal its internal organs by sending out radiation, stay black or what?

    Could we observe some of these happenings?

    1. Interesting. The smallest observed black holes are about 5 SM so its likely smaller black holes don’t have the physics to exist. The next step down for a compact object is apparently a 2 SM neutron star, with nothing in between. So its likely a black hole smaller than about 5 SM would explode. You better believe it would be observable.

  6. I like Simenl’s query, but all you guys have it all wrong.
    Kirk knew what to do and we have to take his lead and get us some dilithium crystals. Scotty proved that was the only way to get lots of antimatter. Once we get started I think we’d want Mr. Hawking looking over our collective shoulder.
    Come on, Frazer! Figure out something practical – such as has the passage of time been constant throughout the history of the universe? Is it constant now? Could we tell if it wasn’t?
    (But really, I do like your flights of fancy.)

    1. If black holes contain a singularity, two merging black holes would have the combined mass of the two. But if black holes contain a finite size star greater than roughly 0.75 SR composed of hot quark type matter, then the merger of two approximately equal mass black holes should result in the explosive escape of some of the black holes’ contents from the merger point. It would be a mini big bang. Maybe an ancient explosion like this occurred in M87.

  13. Is it possible for a worm hole to bleed the mass of a black hole to where the lost mass causes the black hole to no longer be massive enough to trap light and reemerge as just a super dense core?

    1. I don’t know but its an interesting thought if somehow mass escaped a black hole so it became significantly smaller than 5 SM. My guess is it would explosively eject mass. There must be a reason why black holes smaller than 5 SM have not been observed.

      There also has to be a reason why neutron stars are limited to 2 SM. My belief is above 2SM some neutrons in the core collapse, releasing mostly radiation which the neutron star can’t contain.

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