11．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 k，the heat escapes quickly．The moon gets very cold．

11．月球上的气温变化

天文学家们能准确说出月球表面的温度：月球阳面的温度比沸水高2度，其阴面温度低到零下243度。

在月食时，地球的阴影投射在月球上，这时月球的温度可以在瞬间下降300度。

像这样的温度骤变在地球上是不会发生的，但为什么会发生在月球上呢？天文学家们认为，月球的表面是尘埃，而地球上岩石能储存太阳的热量。当太阳下山时，岩石依旧保持温暖，但月球上的尘埃不能存热。所以当月球变得黑暗时，热量便迅速消失，月球便变得不胜寒了。