Overview

• Lunar Laser Ranging using Apollo-era retroreflectors confirms the recession rate at roughly 3.8 centimeters (1.5 inches) per year with millimeter-level precision.
• Tidal bulges in Earth's oceans slightly lead the Moon and transfer angular momentum, which expands the Moon's orbit and imperceptibly slows Earth's rotation.
• Fossil and geological records support the slowdown, including evidence that a day lasted about 23.5 hours roughly 70 million years ago.
• The Moon’s elliptical orbit shifts its distance by around 12,000 miles each month, a variation far larger than the annual outward drift.
• Total solar eclipses are expected to become rarer over time, and projections suggest solar brightening and later red-giant evolution will interrupt tidal endgames long before any Earth–Moon tidal locking.