Black hole: Gravity gone wild
Black holes are thought to be the end of a massive star that has burned itself out. Gravity forces it to collapse upon itself, prohibiting all light from escaping from its center. If you were to fall into a black hole, gravity would wreck havoc with your body. As one mathematician surmises, you would be crushed in so many directions and stretched so thin in others that you would resemble a piece of spaghetti. But you’re safe if you don’t regularly travel in space, right? Except one thing – black holes move through space.
Thankfully, a black hole is not likely to bear down on Earth anytime soon. NASA assures us that there are no black holes close enough to the Earth to cause a problem, and that our sun is not big enough to create one should it collapse. (Though we’d have other things to worry about then.)