Lunar Reconnaissance Orbiter Camera
:: Homepage > Outreach > Explore the Moon > How did the Moon form? ::

How did the Moon form?

Today, there are several main theories on the origin of the Moon. The most widely accepted of these theories states that the Moon formed after a Mars-sized protoplanet (a young planet not yet fully formed), collided with the early Earth over 4 billion years ago. This massive collision produced debris that eventually coalesced due to gravitational forces to form the Moon.


Image Credit: William Hartmann, space artist



For printable version: Click Here