The Moon

The Moon is a ball of rock, 3476 km in diameter, that circles the Earth and is 384,400 km away. The Moon takes 28 days to go round the Earth. It is 4.6 billion years old. There are flat plains, valleys, mountains, and craters on the Moon's surface. Astronauts have landed on the Moon and mapped its surface. As the Moon travels around the Earht we see different parts of its sunlit side. This gives us the phases of the moon.