Overview
- New analyses funded by NASA and reported in scientific journals find a small slowdown in Earth’s rotation that precision instruments can detect.
- Since 2000, melting ice and water moving toward the oceans have shifted mass on the planet, adding about 1.33 milliseconds per century to the length of a day.
- Lunar tides remain the main long-term brake on the planet’s spin, and ancient eclipse records show that days were shorter in the distant past.
- Timekeepers at the International Earth Rotation Service track the gap between atomic time and Earth’s rotation, and the U.S. Naval Observatory says no leap second will be added in June 2026.
- Large shocks and big projects only budge the clock by microseconds, such as the 2004 Indian Ocean quake or the water held by China’s Three Gorges Dam, and a 25-hour day would take roughly 200 million years.