The moon is the earth's natural satellite and the object in space that is closest to us. It has no atmosphere and its gravity is only one of the earth’s.

The moon revolves around the earth at an average distance of about 400,000 km and at a speed of 3,700 km an hour. It completes one orbit around the earth about every days. Because it takes the moon the same time to rotate around its own axis we can only see the same side of the moon all the time. Nobody, apart from astronauts have ever seen the side of the moon.

We can see the moon in different phases as it travels around the earth depending on how much of the sunlit half can be seen on earth.

The moon is made up of gigantic areas called "mare" but it also has high mountains and that were created through the impact of .

Ocean tides are caused by the influence of the moon. Because of its pull sea levels can rise up to 10 metres in some areas.

The moon is the only object in space that human beings have visited. In 1969, the American spacecraft landed on the moon and two astronauts - Neil Armstrong and "Buzz" Aldrin - became the first people to set foot on the moon. Between 1969 and 1972 there were six landings on the moon. But in the last 40 years nobody has visited it.