How Is the Moon Slowly Drifting Away from Earth?

💡 The Answer

• Tidal interactions transfer angular momentum from Earth's rotation to the Moon's orbit.
• The Moon moves away at about 3.8 centimeters per year, measured by laser ranging.
• In the early solar system, the Moon was much closer and Earth's day was shorter.
• In about 50 billion years, Earth-Moon tidal locking would make one Earth day equal one lunar month.