The Moon is Earth’s largest satellite and the only other body in the universe that has been visited by humans. It is the fifth largest satellite in the solar system. Its orbit period is 27 days and is in a synchronous orbit with Earth, meaning we only ever see one side of it.
In Astronomy, "the Moon" with a capital 'm', refers to the big, bright shape in the night sky that we see from Earth. The word "moon", with a lowercase 'm', refers to a large satellite orbiting any planet.
The Moon is Earth’s largest natural satellite. It was thought to have formed not long after the Earth had first formed, about 4.5 billion years ago and is composed of similar materials as Earth.
It is the fifth largest natural satellite in the solar system. It has a synchronous rotation with Earth, meaning we only ever see one side of it as it orbits the Earth. It has an orbital period of 27 days. During this time, we see the Moon as different shapes in the night sky. These phases of the Moon are caused by the relative position of the Moon, Earth, and Sun.
A competition between the Soviet Union and the USA, known as the Space Race, led to an acceleration of advances in lunar exploration. The Soviet Union managed to become the first country to impact a human made spacecraft on the Moon. The Moon is the first (and so far only) object in our solar system that humans have visited. On July 21, 1969 Neil Armstrong, commander of the Apollo 11 mission, became the first person to walk on the Moon. He was one of twelve people to walk on the surface of the Moon, the last person have walked on the Moon was Eugene Cernan. Cernan left the lunar surface on December 14, 1972 as part of the Apollo 17 mission.
The Moon is a moon, but a moon is not always the Moon.
Be sure to check out the Earth and Moon lesson plans.