We usually think of pollution as a harmful waste substance that threatens the air and water. But some people have become concerned about another kind of pollution. It can be everywhere, depending on the time of day. And it is not thought of as a substance. It is light.
The idea of light pollution has developed with the increase of lights in cities. In many areas, this light makes it difficult or impossible to observe stars and planets in the night sky. Light pollution threatens to reduce the scientific value of research telescopes.
Light pollution is the result of wasted energy. Bright light that shines into the sky is not being used to provide light where it is needed on Earth. Lights that are brighter than necessary also cause light pollution. Recently, two Italian astronomers and an American environmental scientist created a world map of the night sky. The map shows that North America, Western Europe and Japan have the greatest amount of light pollution. (165 words)
Useful Words and Expressions
a mineral substance 矿物
the substance of a speech 讲话的要旨
a man of substance 财主
in substance 实质上，本质上，大体上
sacrifice the substance for the shadow 只图虚名不求实效；舍本逐末
waste one's substance 浪费钱财
become concerned about 开始关心；关心，担忧