皮皮学,免费搜题
登录
搜题
【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
拍照语音搜题,微信中搜索"皮皮学"使用
参考答案:
参考解析:
知识点:
.
..
皮皮学刷刷变学霸
举一反三
【单选题】动点的牵连速度是指该瞬时牵连点的速度,它所相对的坐标系是 。
A.
动坐标系
B.
定坐标系
C.
不必确定的
D.
定或动坐标系都可以
【简答题】血小板生成减少的出血性疾病为( )。
【简答题】呼吸道出血性疾病
【单选题】动点的牵连速度是指该瞬时牵连点的速度,它所相对的坐标系是
A.
动坐标系
B.
定坐标系
C.
不必确定的
D.
定、动坐标系均可
【简答题】汉译英。 1. 我们应该最大限度的利用我们校园里的各种资源。
【简答题】妊娠晚期常见的出血性疾病是什么?()
【简答题】(名词解释)出血性疾病
【单选题】用于判断微小心肌损伤的指标是( )
A.
天门冬氨酸氨基转移酶(AST)
B.
肌酸激酶同工酶(CK-MB)
C.
乳酸脱氢酶(LDH)
D.
肌酸激酶(CK)
E.
心肌肌钙蛋白T(cTnT)
【简答题】出血性疾病名词解释出血性疾病
【单选题】诊断急性心肌梗死特异性最高的酶是
A.
血清肌酸激酶同工酶(CK-MB)
B.
天门冬氨酸氨基转移酶(AST)
C.
丙氨酸氨基转移酶(ALT)
D.
乳酸脱氢酶(LDH)
E.
碱性磷酸酶(AKP)