The Galileo spacecraft sent back this image of the Moon as it headed into the outer solar system. The distinct bright ray crater at the bottom of the image is the Tycho impact basin.

Our Moon makes Earth a more livable planet by moderating our home planet's wobble on its axis, leading to a relatively stable climate, and creating a rhythm that has guided humans for thousands of years. The Moon was likely formed after a Mars-sized body collided with Earth and the debris formed into the most prominent feature in our night sky.

Featured Mission: GRAIL
The Gravity Recovery And Interior Laboratory (GRAIL) mission will create the most accurate gravitational map of the Moon to date, improving our knowledge of near-side gravity by 100 times and of far-side gravity by 1000 times.

Read More About Earth's Moon