The Moon is leaving. Has been for billions of years.
The Moon is leaving. Has been for billions of years. Every single year, it drifts about 3.8 centimetres further away from Earth — roughly the same rate your fingernails grow. That doesn't sound like much, but the consequences ripple through time in both directions. Tidal forces between the Earth and Moon are the culprit. As the Moon pulls on our oceans, it slowly bleeds energy from Earth's rotation, putting a subtle brake on our spinning planet. Hundreds of millions of years ago, a day here lasted only around 22 hours. We've gained nearly two hours since then, and we'll keep gaining more. One distant consequence is quietly poetic: eventually, the Moon will appear too small in our sky to cover the Sun completely. Total solar eclipses — gone. We happen to live in the brief window when they're possible. Follow Deep Field Vault for more of the universe.