Book 8, Question 48
Why Is the Moon Slowly Drifting Away From Earth?
The Moon is drifting away because ocean tides pass a little of Earth's spin energy to it! That nudges the Moon about 3.8 centimeters farther away each year. That is about how fast your fingernails grow.
More fun facts
- The Moon drifts about 1.5 inches (3.8 centimeters) farther from Earth each year, about as fast as your fingernails grow.
- The push comes mostly from Earth's oceans, which bulge toward the Moon and tug on it with their own gravity.
- Long ago, the same tidal forces slowed the Moon's spin while adding energy to its orbit.
- The Moon's drift is slowly getting slower.
- Other moons drift away from their planets too. Saturn's moon Titan is drifting away faster than scientists once thought.
Sources: BBC, NASA Science, NASA
Questions kids ask
How fast is the Moon moving away?
About 1.5 inches a year, roughly as fast as your fingernails grow.