Earth's Spin Is Slowing Down

Excited for the August 21 eclipse? Visit our Eclipse 2017 page to explore the science, history, and myths of the event. The Curiosity team will be viewing the eclipse alongside NASA in Carbondale, Illinois. Follow us on Facebook for live videos, trivia, and interviews on the big day.

As the moon's gravity causes the tides to rise and fall, the motion drains energy from Earth's rotation, slowing it down. And if one rotation equals one day, then the days are slowly but surely getting longer. In 100 years, one day will be about two milliseconds longer than it is now. In billions of years, when the Earth spins at the same rate as the moon orbits it, one day will be equal to about 27 current days.

Share the knowledge!

Key Facts In This Video

  1. Tidal forces cause high tides twice a day: once when the moon is overhead, and once when it's on the other side of the Earth. 00:20

  2. Eventually, the Earth will spin slowly enough that the same side will always face the moon. 01:06

  3. If the moon was too close to Earth, tidal forces from the Earth would cause the moon to disintegrate. 01:21

If you liked this you'll love our podcast! Check it out on iTunes, Stitcher, Google Play Music, SoundCloud, search 'curiosity' on your favorite podcast app or add the RSS Feed URL.