An anonymous reader writes: Contrary to what we were sometimes taught in high school physics, the Earth's gravity is not constant. It actually shows slight variations on different parts of the Earth's surface, and the variations correlate with the density of the material on that surface. The European Space Agency has been measuring gravity for four years, mapping these variations and recording the changes those variations have undergone. Its data indicates "a significant decrease [in gravity] in the region of Antarctica where land ice is melting fastest. Further analysis is, of course, planned so that the whole of Antarctica can be taken into account and "the clearest picture yet of the pace of global warming" can be determined on that continent.