Of all the stars that can give out light and heat， the sun is neither the biggest， nor the smallest. It appears very big because it is the closest star to us.

　　The sun is much bigger than the earth. Its diameter¹ is 1.4 million kilometres. If we could put the earth into the sun， the sun could contain 1.3 million earths. If we compare the sun to a basketball， the earth would be only as big as a grain of rice.

　　The sun is 150 million kilometres from the earth. it is so far away that if we could ever walk to the sun， it would take us 3，500years to get there.