Precision and balance keep a top spinning perfectly. What does that make the Earth? Well, as an imperfect sphere of various, variable densities and a liquid core, perhaps only the frictionless environment within which it resides keep it spinning. However, scientists have identified that global warming's effect on ice caps have altered the physical weight distribution on the Earth enough to actually affect the planet's wobble. That's comforting because without global warming, we might have assumed it was a growing imbalance of overweight people condensed on various population centers.