There are many， kinds of stars. Some are big and some are small.

　　There arc nine planets revolving¹ around the sun. The earth is， one of them. Of the nine planets， Jupiter is the biggest. It is one thousand times larger than the earth. But Mercury and Mars， two other planets of the nine， are smaller than the earth.

　　Most of the stairs we see at night are suits very， very far from us. They are fixed² stars. The sun is an ordinary-sized fixed star. There are lots of fixed stars that are bigger than the sun. Sirius we see in the winter night sky， Altair and Vega we see in the summer sky are all bigger than the sun. Of course there are also quite a lot of stars smaller than the sun.

　　The reason that stars all appear to be the same size is because they are far away from us.