A Temperature Change on the Moon　　Astronomers can tell just how hot the surface of the moon gets. The side of the moon toward the sun gets two degrees hotter than boiling water. The night side reaches 243 degrees below zero.　　In an eclipse, the earth's shadow falls on the moon. Then the moon's temperature may drop 300 degrees in a very short time.　　A temperature change like this cannot happen on the earth. Why does it happen on the moon? Astronomers think that the surface of the moon is dust. On the earth, rocks store heat from the sun. When the sun goes down, the rocks stay warm. But the dust of the moon cannot store heat. So when the moon gets dark, the heat escapes quickly. The moon gets very cold.