Inquiring Minds

If you want to truly grasp the scale of the Earth's polar ice sheets, you need some help from Isaac Newton. Newton taught us the universal law of gravitation, which states that all objects are attracted to one another in proportion to their masses (and the distance between them). The ice sheets covering Antarctica and Greenland are incredibly massive—Antarctica's ice is more than two miles thick in places and 5.4 million square miles in extent. These ice sheets are so large, in fact, that gravitational attraction pulls the surrounding ocean towards them. The sea level therefore rises upward at an angle as you approach an ice sheet, and slopes downward and away as you leave its presence.This is not good news for humanity. As the ice sheets melt due to global warming, not only do they raise the sea level directly; they also exert a smaller gravitational pull on the surrounding ocean. So water sloshes back towards the continents, where we all live. "If Antarctica shrinks and puts that water in the ocean, th