The Moon

The directory deals with animations and other files about the Moon.The current best estimate of the age of the Moon is 4.527 billion years.It's is now a well respected view that the Moon was formed as a result of a gigantic collision of a Mars-sized planetismal with Earth early in our planet's formational period. Debris from this collision formed a ring around the Earth which eventually coalesced into the Moon we see today.Right after the Moon was formed, it was quite close to the Earth, perhaps a tenth of its current average distance from Earth. Due to tidal forces between the Moon and the Earth, the Moon migrated outwards from the Earth, the Earth's rotational period increased, and the Moon assumed its current synchronous rotation around Earth.The slowing of the Earth's rotation is quite gradual: the Earth has added only an extra hour per day over the last 250 million years.The Moon orbits the Earth once every 27.3 days. It's orbit is inclined to the Ecliptic Plane by about 5 degrees.It's believed that the Moon's presence limits the long-term variation in the Earth's axial tilt, thereby making seasonal variations in temperature smaller. In contrast, Mars long-term variaton in axial tilt is greater than Earth's, presumably because its two moons are quite small.The Moon is the only Solar System place where humans have visited. The Apollo missions to the Moon are one of humankind's greatest achievements.