Ever notice that when you drop a buttered piece of bread, it drops butter side down? And what about cats? Cats always land on their feet, right? So, the question is, what would happen if you took a piece of buttered bread, strapped it on the back of a cat (butter side up) and dropped the cat from any local precipice? The results are obvious! The laws of butterology demand that the butter must hit the ground, and the equally strict laws of feline aerodynamics demand that the cat can not smash its furry back. If the combined construct were to land, nature would have no way to resolve this paradox. Therefore it simply does not fall. Thats right you clever mortal (well, as clever as a mortal can get), you have discovered the secret of antigravity! A buttered cat will, when released, quickly move to a height where the forces of cat-twisting and butter repulsion are in equilibrium. This equilibrium point can be modified by scraping off some of the butter, providing lift, or removing some of the cats limbs, allowing descent. Most of the civilized species of the Universe already use this principle to drive their ships while within a planetary system. The loud humming heard by most sighters of UFOs is, in fact, the purring of several hundred tabbies.