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　　　In the universe, as we know, there is the Sun, the moon, the Earth and a good many stars. Through our geography lessons, we know the Earth goes round the Sun, and the moon goes round the Earth. We have day and night because the Earth keeps turning all the time. When our part of the Earth turns to the Sun, it is day. When our part of the Earth turns away from the Sun, it is night.

　　 Just because the moon is closer to the Earth than the Sun, it looks much bigger than the Sun. Big things will look smaller when they are farther, and small things also look bigger when they are nearer.

　　The Sun is bright enough to give out very strong light. The moon can't give any light at all, but it looks quite bright, too. Why? In fact, the light from the moon comes from the Sun. The moon looks much bigger and brighter than the stars. But actually (事实上) the stars are much bigger and brighter than the moon. They look smaller than the moon also because they are farther away from the Earth.

　　There are still many other planets in the universe. But of all these planets, only on Earth there are living things and people can only live on Earth, too. But at 9∶00 am on October 15th 2003,Chinese astronaut Yang Liwei was set up to space. He stayed there for 21 hours. It was the first time for Chinese to get into space.