The diameter (the distance through the centre) of the Moon is 3,476km (2,160 miles). That is just under a quarter of the length of the Earth's diameter.
The Earth is nearly 50 times bigger than the Moon, and the Moon is 384,402km (238,867 miles) from the Earth. If the Earth was reduced to the size of a football, the Moon would be the size of an apple. The distance between them would then be 7m (23ft) - about the length of the average sitting room.
Because there is no air on the Moon there is no wind and no weather. The footprints made by astronauts will last forever unless someone disturbs them. There is no sound on the Moon either as there is no air to carry it.
The surface of the Moon has been bombed by meteorites and asteroids for thousands of millions of years. It is pitted with craters of different sizes. Some are tiny, but the largest, the Orientale Basin, must have been made by a huge meteorite. It is 965 km (600 miles) across. If London was on one side of the crater, Berlin in Germany would be on the other.
The Moon has huge mountain ranges. The highest mountain peaks are 6,000m (19,686ft) above the ground, two thirds the height of Mount Everest. There is no weather to wear down the Moon's mountains, so they will always remain that high.
During the day the Sun warms the Moon - up to 100 degrees celcius. That is twice as hot as the hottest place on Earth and hot enough to boil water. At night the temperature plummets far below zero, down to -150 degrees celcius. That is twice as cold as an Antarctic winter.