Why the Moon Matters

The Moon does far more than light up the night. Its gravity holds Earth's axial tilt steady near 23.5 degrees. Without it, the tilt could wobble chaotically over millions of years, triggering climate swings extreme enough to stall the evolution of complex life.

The Moon's tides may also have helped life begin. The twice-daily flooding and drying of tidal pools concentrated organic molecules, then dried and reformed them — a natural chemistry experiment repeated for billions of years.