Scientists are using powerful radio telescopes to "listen" to signals from about 1,000 stars, all within 100 light years of the earth. In addition, they will scan the entire sky to listen for radio messages from more distant stars. Using a computer, they will be able to monitor more than eight million channels at a time. Scientists are looking for any signal that stands out from the background noise.
Of the 200 billion stars in the Milky Way galaxy, scientists find that five percent of the stars are like our sun. Perhaps half of them have a planet like the earth. Such a planet would be a reasonable distance from the star for the temperatures to be right for the evolution of life. Believing that there are the inhabitable (that can be lived in) planets in our galaxy, most scientists agree that chances are that one or more of these planets support some life.
However, many scientists wonder whether intelligent life exists on other planets. Some believe that thirty years of searching without any intelligent messages show that no one is out there. They say that the evolution of intelligence comparable to ours is unlikely.
(44) Other scientists believe that our search hasn't been long enough to rule out the possibility that intelligent life exists in our galaxy. Although our sun family is only about five billion years old, our galaxy is about 20 billion years old. In that time some scientists think it is likely that civilizations are much more advanced than ours. Perhaps these civilizations send us no signals; perhaps we have not recognized the signals they have sent us. If we hope to find intelligent life, these scientists believe that we have to keep looking.
To look for signals from distant stars, scientists______.
A.have sent up spaceships to other planets
B.have sent radio and television messages to outer space
C.are listening to the radio message all the year round
D.will use computers to pick up background noise
第4题
A.3月20号
B.6月20号
C.41779
第5题
科技文件的具体积累最主要的形式是()
A.科技部门积累
B.档案部门代为积累
C.科技人员个人积累
D.科技文件管理人员或兼职档案员积累
第6题
归档是将工作活动中形成的具有保存价值的整理完毕的文件材料定期移交给()。
A.档案室
B.文书部门
C.综合部门
D.业务部门
第7题
属于科技档案部门独立进行的是()
A.组织案卷
B.科技档案分类
C.案卷编目
D.科技文件鉴别
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