A study published in the Proceedings of the National Academy of Sciences reveals that melting polar ice caps are causing Earth to spin more slowly, lengthening days at an unprecedented rate. Water from Greenland and Antarctica increases mass around the equator, akin to a figure skater extending her arms to slow down. Earth’s shape, an “oblate spheroid,” changes due to tides, tectonic drift, and seismic activity. The study used techniques like Very Long Baseline Interferometry and GPS to measure Earth’s rotation precisely. This slowdown increases the length of a day by a few milliseconds.