光污染有哪些,光污染英语作文20词左右

光污染有哪些,光污染英语作文20词左右

ENVIRONMENT REPORT - August 31,2001:Light PollutionBy Mario Ritter（Start at 1'01 ）This is Bill White with with the VOA Special English Environment Report.
We usually think of (1)pollution as a harmful waste (2)substance that threatens the air and water.But some people have become (3)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 (4)observe stars and (5)planets in the night sky.In Nineteen-Eighty-Eight,the International Dark-Sky Association formed.This organization wants to reduce light pollution in the night sky.It also (6)urges the effective use of electric lighting.
There are a number of reasons why light pollution is important.One has become clear at the Mount Wilson Observatory near Los Angeles,California.Mount Wilson Observatory was home to the largest (7)telescopes in the world during the first half of the Nineteen-Hundreds.
During that period,Los Angeles grew to become one of America's biggest cities.
Today,light from Los Angeles makes the night sky above Mount Wilson very bright.It is no longer an important research center because of light pollution.
Light pollution threatens to reduce the scientific value of research telescopes in other important observatories.They include Lick Observatory near San Jose,California and ......余下全文>>