Scientists have always wanted to know more about the other worlds in space. Years ago they knew a lot about the moon. They knew how big it is and how far away it is from the earth. As we all know, there is no air or water on the moon.
It's very hot in the day, but very cold at night. Things are much lighter on the moon than on the earth. It's like jumping. But you can jump much higher on the moon than on the earth. If you can jump one meter on the earth, you can jump six meters on the moon.
But they wanted to know more about it. They thought and thought.
The moon is about 384,000 kilometers away from the earth. A plane cannot fly to the moon because the air reaches only 240 kilometers high above the earth. Then there is no air.
Spaceships can fly out into space. Spaceships-with men in them have already reached the moon. Some spaceships without men in them have flown to other parts, much farther away than the moon in the universe.
A. Walking on the moon is much more difficult.
B. One day spaceships may be able to go to any place.
C. So there are no living things on the moon.
D. But something can fly even when there is no air.
E. At last, they found the only way to know more was to send man to the moon.
