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【单选题】
Star birth, which transformed primordial gas into the countless starry galaxies of the present day universe, surged to high levels much earlier than astronomers had thought. Two teams of observers have looked into the early universe for the longwavelength radiation that signal star formation in dusty young galaxies. In tomorrow’s Nature, they report seeing galaxies rapidly spawning stars when the universe was less than a third of its present age. Astronomers have been searching at great distance -- which correspond to earlier times -- to find the heyday of star birth. But interstellar dust is thick in star-forming regions hiding the light of hot young stars and reradiating it in the infra red. Observations by infrared satellites have already revealed large number of star-forming galaxies as much as halfway back to the big bang. But for even older, more distant stars and galaxies, the expansion of the universe stretches the infrared radiation into the submillimeter waveband, a twilight region of the spectrum between infrared and radio. Earlier this year, a U. K. team led by Michael Rowan -- Robinson of London’s Imperial College pointed a submillimeter telescope on Mauna Kea, Hawaii, at the Hubble Deep Field, the small patch of sky where the Hubble Space Tele scope captured optical images of some of the most distant galaxies ever. Five of the brightest submillimeter sources they found match up with faint, old galaxies in the Hubble image, and four of the five date from when the universe was between a third and a fifth of its present age -- up to 9 billion years ago. Their submillimeter brilliance indicates that these galaxies are spawning stars perhaps 100 times faster than our own galaxy, says team member James Dunlop of the University of Ed inburgh. A U. S. -Japanese group has made other submillimeter images that support this picture of frenzied star birth in the early universe. The observations are 'a very exciting new development,' says Max Pettini, an astrophysicist at Britain’s Royal Green wich Observatory. Star formation, he says, is 'part and parcel of the broader question of how the universe evolved from the smooth conditions of the big hang into the galaxies we see today. 'However, Charles Steidel of the California Institute of Technology cautions that the distance and hence the age of these submillimeter sources is 'somewhat ambiguous, 'because of the submillimeter camera’s coarse resolution. From the third paragraph we know that ______.
A.
an American team pointed a submillimeter telescope in Hawaii
B.
the team used Hubble space Telescope and captured optical images of some galaxies
C.
they found five faint old galaxies
D.
there are several galaxies in the universe
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举一反三
【单选题】变速器互锁装置的作用是。
A.
防止同时挂上两个档
B.
防止误入倒挡
C.
给驾驶员以换挡的感觉
D.
保持所换的档位
【简答题】In the boxes below are some of the words you have learned in Text A. Complete the following sentences with the words given. Change the form where necessary. 1) The couple are unable to have children o...
【单选题】Can I take Lisa to the aquarium tomorrow? If she ________ there, she _______ a good time. [     ]
A.
goes; has
B.
will go; has
C.
will go; will have
D.
goes; will have
【单选题】到学习通的资源栏中下载无线传感器网络 教材pdf版本,并学习绪论内容。
A.
已下载教材,并学习相关内容;
B.
未下载;
C.
未找到pdf教材;
D.
找到教材,但是文件打不开。
【单选题】交易效用指出,人们评价商品的某一个定价时,参考的是
A.
预期价格
B.
实际价格
C.
价值
D.
参考价格
【单选题】Steady as she goes!()
A.
照直走!
B.
主机定速!
C.
用车完毕!
D.
备车!
【单选题】变速器互锁装置的作用是()
A.
防止变速器自动换挡或自动脱档
B.
防止同时换入两个档
C.
防止误换倒挡
D.
减少零件磨损和换挡噪声
【简答题】U204 The words below are some you have learned in this unit. Complete the following sentences with them. Change the form where necessary. adopt capture confidence convince ...
【简答题】About three months ago, in Hanzhong, Shanxi Province, the local government killed more than 34000 stray dogs (流浪狗) . The officials were afraid that the dogs would spread rabies (狂犬病) . The action caus...
【单选题】按照( )体系标准,对现场试验工作进行管理,并建立相关制度。
A.
GB/T19000——ISO9000
B.
GB/T19000——ISO9001
C.
GB/T19000——ISO9010
D.
GB/T19000——ISO9100
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