Don't miss out on hundreds of dollars off the best skywatching optics and cameras in this week's Amazon Spring Sale.
This is a cool fact to impress your friends. The length of a day on Earth changes constantly, nudged by the Moon's gravitational pull, shifting winds in the atmosphere, and slow churning movements deep within the planet. It always has. Day length is, in a sense, a living measurement and one that ebbs and flows with the rhythms of a restless, dynamic world. But something new is happening.

