Men have always been interested in the moon because it is the biggest and brightest object in the sky at night. In fact, it is really quite small. It looks big because it is so near to us. It is only less than 400 000 kilometres away. It is nearer to us than any other heavenly body in space. Although the moon looks bright, it does not send out any light of its own. It reflects the light of the sun. The moon looks about the same size as the sun, but the sun is actually 400 times bigger and 400 times farther away.
For hundreds of years men have wanted to travel to the moon. Whenever they looked at the moon, they would ask themselves questions: Is the moon hot or cold? Is there any life on the moon? Are there any plants or animals? Do people live there? Could we live there? If you look at the moon through a telescope you can see lines and circles. These are mountains, valleys and deep holes. There are also plains where the ground is quite flat. There are no canals and there is nothing with life on the moon. We know these because scientists have studied the moon through telescopes, and by using other instruments, for many years. In recent years spaceships with men inside have reached the moon..
The moon travels around the earth at about 384 000 kilometres an hour. Days and nights on the moon are much longer than on the earth. One day, or one night, on the moon is as long as two weeks on the earth. In the daytime the moon is much hotter than the earth. It reaches a temperature of 120℃. The nights are much colder:-150℃. A man on the moon would have to wear special clothes or he would freeze to death at night or die of the heat by day. On the moon things are not so heavy as they are on the earth. Something that weighs one kilogram on the earth would weigh only about 160 grams on the moon.