If you are traveling forwards in a

If you are traveling forwards in a train, surrounding objects outside appear to be moving backwards. But this is not in fact the case. It is the train which is moving. So it is with the earth . The sun appears to rise in the east, move across the sky, and set in the west .In other words, the sun appears to travel round the earth. In fact, however, this is not the case. It is the earth which is rotating on its own axis. the rotation of the earth on its own axis causes the change from day to night. The earth also travels round the sun on a fixed path, known as an orbit. In addition to the earth, there are eight other planets of different sizes, all rotating on their own axes and round the sun in their own fixed orbits。