Black hole (InstanceTopic, 7)
From Compile Worlds
A black hole is a rather fearsome astronomical object. Taken at face value, they have infinite gravity and can suck in anything that's close enough. An explosion with roughly three times the force of an H-bomb would supposedly create a black hole, so anyone capable of manufacturing and detonating such a powerful bomb could destroy the world. If all the "little" black holes in the universe gradually expand and merge into one giant black hole this could suck up every last atom in the universe. Black holes also screw around with time and space, leading philosophers to believe that crazy ideas like time travel and quantum computing are actually possible.
If you read more into it though, you find a little more faith in the universe: black holes actually spew out particles in two jets, perpendicular to their plane of rotation. This is only possible thanks to quantum mechanics creating particle-antiparticle pairs right at the event horizon, reducing the energy and mass of the black hole as the particles escape. This puts matter back into the observable universe, allowing it (and its high kinetic energy) to be reused. A second nicety is that although black holes' "reach" grows as the mass of the black hole increases, allowing it to suck in more and more that it couldn't before, the inverse square law of gravity will kick in, so the growth in reach gets slower and slower until it's consumed all matter it can and can't grow any more, with everything else still orbiting stably around it. These two facts combined mean any black hole will disintegrate eventually, leaving a large region of completely empty space where it once existed, and putting the matter and energy it consumed back into something productive in the universe.