Turns out there are four basic forces that hold the universe together, and out of these four, gravity is the only one that doesn't make any sense. Specifically, how it can be so incredibly weak and incredibly strong at the same time. Gravity holds the entire universe together, and no matter how far out you travel, it never completely disappears. And yet, it is the weakest force in existence. To illustrate, you know when you bring two magnets near each other and they snap together? That force is actually 10^36 times stronger than gravity. Yeah, the technical term for that is "a big-ass order of magnitude" stronger.
To add to the confusion, because all these other forces are controlled by their own particles, it stands to reason that gravity should have its own particles, too. But this hypothetical critter -- the graviton -- is basically the only one we haven't found yet, unlike the particles that mediate a lot of the other important forces in nature, which have been altogether more cooperative.
But the mother of all baffling gravity mysteries is that, once you get down to the level of atoms and molecules and even smaller stuff, gravity just plain stops working. In fact, gravity is one of the biggest reasons why quantum physicists and real-world physicists have nothing to say to each other. We know more about what's inside an atom than we do about why a ball comes back down when we throw it in the air. For all science knows, it's because of ghosts.
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http://www.cracked.com/article_1944...eve-science-cant-answer_p2.html#ixzz2xUzBbsAJ
