Why does the Moon slowly move away from Earth?
Quick Answer
Tidal interactions transfer Earth’s rotational energy to the Moon’s orbit, pushing the Moon outward by about 3.8 cm each year.
The Full Story
Earth’s gravity raises tides on the Moon and the Moon raises tides on Earth, and the resulting friction changes both bodies over time. Because Earth spins faster than the Moon orbits, the tidal bulge is carried slightly ahead of the Moon, which gives the Moon a gravitational tug and increases its orbital distance. Measurements from laser reflectors left by Apollo astronauts show that the Moon recedes at about 3.8 centimeters per year. This process also gradually slows Earth’s rotation, making days longer over very long timescales.
Key Facts
YouTube Angle
Suggested video title for this topic:
"The Moon is drifting away from Earth—here’s the tidal reason."
Was this answer helpful?
Tap a reaction — it helps us pick what to cover next.