It might not be a good idea, but if we wanted to make a black hole on Earth, would it be possible and how would we do it?
On September 10, 2008, it was widely speculated the world would come to an end. A black hole would explode from the Franco-Swiss border near Geneva, consume the entire Earth and annihilate its entire mass. Those who believed were mostly fools, though. On that day, the Large Hadron Collider, a 17 mile particle accelerator, came online, and the Earth remained largely unswallowed by a black hole. The Large Hadron Collider (LHC) is a remarkable piece of human engineering. It took 10,000 of the world’s premiere scientists 10 years to build it. And it’s sole purpose is to accelerate atomic particles to 99.9999991% the speed of light, smash them together, and see what happens. The doomsday obsessed believed the LHC would be too powerful, and the collisions would tear the Earth apart. The LHC didn’t do this—the science behind the theory didn’t make sense—but what if we wanted it to.
A black hole is essentially a ludicrous amount of mass concentrated in an incredibly small space. They’re called singularities because gravity becomes measurably infinite at a single point. They suck in everything around them like cosmic vacuum cleaners, and past the event horizon of a black hole nothing can escape, not even light.
Black holes come in different flavors. Some are the result of a dying star collapsing in on itself (stellar-mass black holes). Others were cooked up at the beginning of the universe through processes we don’t understand. These supermassive black holes sit at the center of galaxies, pulling and twisting worlds. Though the black holes we’ve observed up to this point have been large on a cosmic scale, that doesn’t mean it’s impossible for micro black holes to exist. It might be out of our league to force the collapse of a star, but maybe creating a micro black hole is within human reach.
Now we know that a micro black hole is on the menu, how do we go about making one? If we go back to the LHC and the doomsdayers who thought it would swallow the Earth, we can find our answer (or at least part of it). The entire premise particle accelerators espouse is that the high-speed smashing of atomic bits can create new particles. These collisions break into the fundamental forces: electromagnetism, the weak force, the strong force, and—here’s the winner—gravity. A black hole is essentially the creation of a high energy collision event. If we have enough energy to manipulate gravity, we can create a black hole.
Gravity, on a cosmic scale, is a the weakest of the fundamental forces. Every time you lift something off a table or jump or just move at all, your body is overpowering the downward force of gravity. This is because your mass, in comparison to the mass of the entire Earth, is relatively small, and the distance between the center of masses (the center of the Earth vs. the surface) is relatively large. But the gravitational force follows the inverse-square law. Meaning as two objects get closer together, the force increases exponentially. At the distance of a Planck length, gravity would overpower the other fundamental forces. If a collision would occur within a Planck length, a micro black hole could form. Problem is a Planck length is small, really small, 1.616 x 10-35 meters small. If you could visualize the entire observable universe in front of you, a Planck length would be as large as the smallest dot you could see. Small.
And a further complication is that as things get smaller, more energy is required to manipulate them. Corresponding to a Planck length, is Planck energy or around 1019 giga-electronvolts. While this is only 1.3 times the energy a lightning strike provides, it would all need to be channeled within a Planck length. In four-dimensional space as we know it, this is way out of the LHC’s capabilities.
So let’s make another jump and say theories of extra-dimensionality are viable to making our personal black holes. Some ideas concoct additional dimensions that, while still microscopic to humans, would facilitate the formation of micro black holes at significantly smaller energies. If gravity could traverse through these extra-dimensions, a black hole we might yet make. (It’s important to know that if a black hole formed at these lower energy levels, it would both prove our ability to make black holes, and the existence of these additional dimensions. Boom! Nobel Prize.)
But even if all of this worked out, we’d still have a hard time determining if we actually made a black hole or not. As black holes decay they release Hawking radiation. The amount of radiation and rate of decay is related to the size of the black hole. The larger ones decay slowly, whereas the little ones go fast releasing a whole lot of radiation with them. If we were to create a micro black hole, it’d collapse instantly, posing no threat of engulfing the Earth. But it’d leave behind a signature of radiation to show it’d once been there. But because there are so many theories about the specificity of these extra dimensions, we wouldn’t know sort of signature to look for. It’s possible scientists are creating black holes all the time without ever knowing. It’s not likely, but it is possible.
A lot of assumptions are required, but yeah, we could make black holes on Earth if we really wanted to. And if we succeeded, it’d set many pieces in the puzzle of understanding how general relativity and quantum mechanics are connected. But it wouldn’t end the Earth. And if it did, that’d definitely be a Nobel Prize winning experiment.