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  • Black holes can destroy everything, but can they be destroyed?

  • What happens if we push physics to the absolute limit, maybe even breaking it and the universe in the process?

  • Let's create a tiny black hole about the mass of our moon in the Kurzgesagt labs and try to rip it apart.

  • Experiment 1

  • Nuke it

  • Big booms break things, so to set the mood, let's explode the world's entire nuclear arsenal around our black hole.

  • Boom!

  • Black holes swallow whatever crosses their event horizon, matter and energy.

  • And since E equals mc squared, all the energy that enters a black hole increases its mass.

  • The mass of a black hole is proportional to its size, so as we nuke our tiny black hole, it just gets bigger and more massive.

  • Experiment 2

  • Antimatter

  • Matter and antimatter annihilate each other.

  • What will happen if we throw a moon's mass of antimatter at it?

  • Unfortunately, when an object enters a black hole, the black hole will completely delete its past identity, whether it's made of matter or of antimatter.

  • Black holes only care about gravity, which only depends on the total mass-energy of an object.

  • And the mass of a particle is the same as its corresponding antiparticle, so throwing an antimoon has the same effect as throwing a moon.

  • The black hole just gets more massive.

  • This deleting ability of black holes is pretty interesting.

  • It means that despite their size and power, black holes are, in a way, similar to elementary particles.

  • An elementary particle, like an electron, is an extremely simple object, fully specified by just three numbers, its mass, spin, and charge.

  • And, amazingly, the same is true for black holes.

  • They have a mass, they can rotate, and carry an electric charge.

  • Once a black hole forms, it doesn't matter if it comes from a collapsed star, an antistar, or a banana, it will always be fully described by those three numbers, nothing else.

  • But if a black hole is basically a weird particle, could we destroy it with an anti-black hole?

  • How exciting!

  • A particle has the same mass as its corresponding antiparticle, but opposite charge.

  • Since a black hole has mass and electric charge, its corresponding anti-black hole should have the same mass and opposite electric charge.

  • What if we make them collide?

  • Sadly, the charge will just add up and cancel out.

  • So, after the collision, we'll just get a new black hole twice as massive with no charge.

  • Okay, we need to think bigger, and stretch physics harder.

  • It's true that a black hole can carry spin and charge, but even for these crazy objects, there are limits.

  • If the spin or the charge of a black hole becomes too large, something really weird will happen.

  • The event horizon will dissolve.

  • In a simplified way, we think of black holes as hiding a singularity inside, an infinitely compressed mass with such strong gravity that absolutely nothing can escape from its surroundings, not even light.

  • This is why a black hole looks like a black sphere of nothingness.

  • The event horizon is the outer edge of this ultimate prison.

  • Cross it, and you'll never be able to come back.

  • But when a black hole rotates, it works a bit like a spinning washing machine.

  • It's as if the rotation wants to repel nearby objects and push them out of the black hole, which doesn't happen because its gravity is so strong.

  • But, if the rotation gets too fast, this effect will win, and the event horizon will disappear.

  • Nearby objects won't be imprisoned forever anymore.

  • The same thing happens with the electric charge.

  • Make it too large, and our ironclad jail will break open.

  • If we manage to destroy the event horizon, the singularity would still be there, and objects would still naturally fall towards it.

  • If you hit it, you would still die horribly and quickly.

  • But the vicinity of the singularity won't be an inescapable prison anymore.

  • You could get as close as you want and come back.

  • This should count as destroying the black hole.

  • Can we do it?

  • Experiment 5. Overfeeding.

  • All we have to do is to overcharge or overspin the black hole.

  • We could do this by throwing objects with a small mass and a lot of charge or angular momentum so that the charge or spin increases faster than the mass.

  • We have to overfeed the black hole until it reaches the point where it breaks open.

  • However, whether you can actually do this is the subject of passionate argument among physicists.

  • Think of a charged black hole.

  • Equal charges repel each other, and the more of the same charges you squish together, the more they push back.

  • So let's say that we have a negatively charged black hole and we want to overfeed it with electrons, for example, whose charge is far larger than its mass.

  • The electrons will feel an electrostatic repulsion, and the more electrons we throw, the larger the negative charge of the black hole will be and the stronger the repulsion.

  • But once we reach the upper limit, the electrostatic repulsion will be so strong that it won't allow any more electrons to come in.

  • At this point, the black hole will refuse to be overfed.

  • With the spin, it's similar.

  • Once the black hole reaches its upper limit, it won't gobble more spin.

  • But some scientists have discovered what looks like a loophole.

  • If an instant before the black hole reaches the limit, we throw the right amount of matter in in just the right way, it looks like we could actually overfeed it.

  • Most scientists are skeptical, but let's give it a try anyway.

  • The end.

  • Breaking physics.

  • There is a catch, though.

  • The event horizon of a black hole hides the singularity.

  • So destroying the horizon would leave us with a naked singularity, one that is not hidden by an event horizon.

  • And this poses a problem.

  • It could mean the end of physics as we know it.

  • There's a big dirty secret about black holes.

  • Contrary to widespread belief, the singularity of a black hole is not really at its center.

  • No, it's in the future of whatever crosses the horizon.

  • Black holes warp the universe so drastically that at the event horizon, space and time switch their roles.

  • Once you cross it, falling towards the center means going towards the future.

  • That's why you can't escape.

  • Stopping your fall and turning back would be just as impossible as stopping time and traveling to the past.

  • So the singularity is actually in your future, not in front of you.

  • And just like you can't see your own future, you won't see the singularity until you hit it.

  • But you also can't hit something that's in your future, only sort of experience it, like you'll experience your next birthday when it happens.

  • Singularities that are in the future are not a problem because we can't see them or interact with them.

  • But a naked singularity would be in front of us for all of us to see.

  • What would we see?

  • Well, the whole point is that it's impossible to know.

  • A singularity is a region of infinite gravity, and gravity is the bending of space-time.

  • At a singularity, the bending is so radical that the fabric of space-time is literally broken.

  • Space and time don't exist anymore.

  • This means that you can't predict anything, since predicting means making a forecast about where and when something will happen.

  • But where and when have lost their meaning.

  • So we have an unpredictable thing with infinite gravity and therefore infinite energy.

  • This means that anything could come out of it for no reason, from a pile of bananas to lost socks or a solar system.

  • Predictability, causality, and physics as we know it would break down.

  • We think that singularities should exist in nature because we can prove that under very general conditions, gravitational collapse leads to the formation of singularities.

  • However, scientists think that nature forbids the formation of naked singularities.

  • Something enforces the creation of an event horizon around them to prevent their insanity from infecting the rest of the universe.

  • Without event horizons, physics may not make sense at all.

  • So although black holes have been portrayed as the ultimate monsters of the universe, they may actually be the heroes that keep us safe from the madness of singularities.

  • So if we do destroy the horizon, we might destroy the fundamental rules of the universe.

  • You know what? Let's not do that.

  • Conclusion.

  • The safe option.

  • As far as we know, there's just one safe method to destroy a black hole.

  • Wait.

  • All black holes emit tiny particles, a phenomenon called Hawking radiation.

  • This process causes them to slowly lose mass until they eventually evaporate, leaving behind no horizon and no naked singularity.

  • The time it takes for a black hole to completely evaporate depends on its mass.

  • For our mini black hole, the size of a speck of dust, it will be about 10 to the power of 44 years.

  • 10 billion trillion trillion times the present age of the universe.

  • So is it possible to destroy a black hole?

  • Yes. We just have to wait.

  • But you don't have to wait that long.

  • There are plenty of fascinating things to explore right here on this planet right now, if you have the knowledge to understand them.

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Black holes can destroy everything, but can they be destroyed?

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