Mars is Spinning Faster and Faster

A day on Earth last about 24 hours. The word “about” in that sentence does a lot of heavy lifting because Earth’s rate of rotation changes all the time. Not by much, only fractions of milliseconds, but it means our common 24-hour day only really applies at human scales.

There are several things that can change the Earth’s rotation. The gravitational tug of the Moon and tides are gradually slowing Earth over millions of years. The melting of ice in the polar regions, the tectonic shift of the Earth’s crust during earthquakes, and even the draining of water from the aquifer. Earth is a geologically and biologically active world, so it’s only natural that Earth’s rotation rate is also dynamic. But a recent study shows that the rotation of Mars is also changing, which is a bit of a surprise.