Icy Microbes

1　In ice that has sealed a salty Antarctic lake for more than 2,800 years, scientists have found frozen bacteria and algae that returned to life after thawing. The research may help in the search for life on Mars, which is thought to have subsurface lakes of ice.

2　A research team led by Peter Doran of the University of Illinois at Chicago drilled through more than 39 feet of ice to collect samples of bacteria and algae. When Doran’s team brought them back and warmed them up a bit, they sprang back to life.

3　Doran said the microbes have been age-dated at 2,800 years old, but even older microbes may live deeper in the ice sheet sealing the lake, and in the briny water below the ice.¹ That deeper ice and the water itself will be cautiously sampled in a later expedition that will test techniques that may one day be used on Mars.

4　Called Lake Vida, the 4.5-square-kilometer body is one of a series of lakes located in the McMurdo Dry Valleys of Antarctica, some ² ,200 kilometers due south2 of New Zealand. This lake has been known since the 1950s, but people ignored it because they thought it was just a big block of ice. While at the site for other research in the 1990s, Doran and his colleagues sent³ radar signals into the clear ice covering the lake and were surprised to find that 62 feet below there was a pool of liquid water that was about seven times more salty than seawater.

5　That prompted the researchers to return in 1996 with equipment to drill a hole down to within a few feet of the water layer. At the bottom of this hole, researchers harvested specimens of algae and bacteria.

6　The researchers will return in 2004 equipped with instruments that are sterilized. They will then drill through the full 62 feet of ice and sample some of the briny water from the lake for analysis. The water specimen will be cultured to see if it contains life. Specimens from the water are expected to be even older than the life forms extracted from the ice covering.

 

词汇： 

alga / ’ælgə/ n．水藻（复数algae）

thaw / θɔ: / v．解冻

briny / ’braɪnɪ/ adj．咸的，海水的

specimen / ’spesɪmɪn / n．样本，标本

sterilize / ’sterɪlaɪz / v．杀菌，消毒

culture / ’kʌltʃə(r)/ v．培养（微生物等）

 

注释：

1．... live deeper in the ice sheet sealing the lake, and in the briny water below the ice：in the ice sheet sealing the lake和in the briny water below the ice是介词短语，用作状语，修饰live。

2．due south：正南

3．While at the site for other research in the 1990s, Doran and his colleagues sent ... ：While at the site for other research in the 1990s是省略句，写全了就是：While Doran and his colleagues were at the site for other research in the 1990s ...

A　is found to be a great deal higher than that of seawater

B　was of little scientific value

C　may be older than that collected below 39 feet of ice

D　might have come from Mars

E　is to collect some briny lake water for analysisy

F　may return to life sooner than microbes frozen in the surface ice

Scientists expect that the life, if found in deeper water below the ice sheet, ________.

A:A B:B C:C D:D E:E F:F

"Life Form Found" on Saturn"s Titan

Scientists say they have discovered hints of alien life1 on the Saturn"s moon2. The discovery of a sort of life was announced after researchers at the US space agency,NASA3,analyzed data from spacecraft Cassini4,which pointed to,the existence of methane-based form of life on Saturn"s biggest moon.

Scientists have reportedly discovered clues showing primitive alien beings are"breathing" in

Titan"s dense atmosphere filled with hydrogen.

They argue that hydrogen gets absorbed before hitting Titan"s planet-like surface covered with methane lakes and rivers. This,they say,points to the existence of some"bugs"5 consuming the hydrogen at the surface of the moon less than half the size of the Earth.

"We suggested hydrogen consumption because it"s the obvious gas for life to consume on Titan,similar to the way we consume oxygen on Earth,"says NASA scientist Chris McKay."If these signs do turn out to be a sign of life,it would be doubly exciting because it would represent a second form of life independent from water-based life on Earth."

To date,scientists have not yet detected this form of life anywhere,though there are liquid-

water-based microorganisms on Earth that grow well on methane or produce it as a waste product. On Titan, where temperatures are around 90 Kelvin6(minus 290 degrees Farenheit),a methanebased organism would have to use a substance that is liquid as its medium for living processes, but not water itself. Water is frozen solid on Titan"s surface and much too cold to support life as we know it.

Scientists had expected the Sun"s interactions with chemicals in the atmosphere to produce a coating of acetylene on Titan"s surface. But Cassini detected no acetylene on the surface.

The absence of detectable acetylene on the Titan"s surface can very well have a non-biological explanation,said Mark Allen,a principal investigator7 of the NASA Titan team.

"Scientific conservatism suggests that a biological explanation should be the last choice after all non-biological explanations are addressed,"Allen said. "We have a lot of work to do to rule out8 possible non-biological explanations. It is more likely that a chemical process,without biology,can explain these results."

 

词汇：

Saturn /"sætən/ n．土星        

methane/"mi:θein/ n．甲烷，沼气

Titan/"taitən/ n．土卫六       

acetylene/ə"setili:n/ n．乙炔

alien/"eiljən/ n．外星人；adj．外星球的；相异的 

conservatism/kən"sʒ:vətizəm/ n．保守主义,守旧

 

注释：

1.hints of alien life：外星生命迹象。

2.the Saturn"s moon：指土卫六（Titan) 。土卫六又称泰坦星，是土星卫星中最大的一颗。

3.NASA：美国国家航空航天局的缩写，全称是： National Aeronautics and Space

Administration。

4.spacecraft Cassini：卡西尼号探测器，以出生于意大利的法国天文学家卡西尼的名字命名，其任务是环绕土星飞行，对土星及其大气、光环、卫星和磁场进行深人考察。1997 年10 月15日，重六吨的“卡西尼”号星际探测器被发射飞往土星的轨道。这是上世纪发射的最后一艘行星际探测的大飞船。“卡西尼”号用了将近七年时间，在2004 年7月1日飞达土星轨道。

5.bugs：微生物。非正式口语表达，所以使用了引号。

6.Kelvin：可翻译成“绝对温度”。Kelvin Scale ，绝对温标，开氏温标，是由Kelvin 勋爵于19世纪中叶发明的温度计量方法，其零度相当于摄氏一273. 15" C ，被认为是宇宙中最低温度。这种温度计量方法多为科学家使用。

7.principal investigator：研究项目负责人

8.rule out：排除……的可能性

What have scientists found about Saturn?

A:They have found a new moon orbiting Saturn. B:They have found methane-based life on Saturn. C:They have found methane-based life on Titan. D:They have found earthlike life on a Saturn"s moon.

"Life Form Found" on Saturn"s Titan

Scientists say they have discovered hints of alien life1 on the Saturn"s moon2. The discovery of a sort of life was announced after researchers at the US space agency,NASA3,analyzed data from spacecraft Cassini4,which pointed to,the existence of methane-based form of life on Saturn"s biggest moon.

Scientists have reportedly discovered clues showing primitive alien beings are"breathing" in

Titan"s dense atmosphere filled with hydrogen.

They argue that hydrogen gets absorbed before hitting Titan"s planet-like surface covered with methane lakes and rivers. This,they say,points to the existence of some"bugs"5 consuming the hydrogen at the surface of the moon less than half the size of the Earth.

"We suggested hydrogen consumption because it"s the obvious gas for life to consume on Titan,similar to the way we consume oxygen on Earth,"says NASA scientist Chris McKay."If these signs do turn out to be a sign of life,it would be doubly exciting because it would represent a second form of life independent from water-based life on Earth."

To date,scientists have not yet detected this form of life anywhere,though there are liquid-

water-based microorganisms on Earth that grow well on methane or produce it as a waste product. On Titan, where temperatures are around 90 Kelvin6(minus 290 degrees Farenheit),a methanebased organism would have to use a substance that is liquid as its medium for living processes, but not water itself. Water is frozen solid on Titan"s surface and much too cold to support life as we know it.

Scientists had expected the Sun"s interactions with chemicals in the atmosphere to produce a coating of acetylene on Titan"s surface. But Cassini detected no acetylene on the surface.

The absence of detectable acetylene on the Titan"s surface can very well have a non-biological explanation,said Mark Allen,a principal investigator7 of the NASA Titan team.

"Scientific conservatism suggests that a biological explanation should be the last choice after all non-biological explanations are addressed,"Allen said. "We have a lot of work to do to rule out8 possible non-biological explanations. It is more likely that a chemical process,without biology,can explain these results."

 

词汇：

Saturn /"sætən/ n．土星        

methane/"mi:θein/ n．甲烷，沼气

Titan/"taitən/ n．土卫六       

acetylene/ə"setili:n/ n．乙炔

alien/"eiljən/ n．外星人；adj．外星球的；相异的 

conservatism/kən"sʒ:vətizəm/ n．保守主义,守旧

 

注释：

1.hints of alien life：外星生命迹象。

2.the Saturn"s moon：指土卫六（Titan) 。土卫六又称泰坦星，是土星卫星中最大的一颗。

3.NASA：美国国家航空航天局的缩写，全称是： National Aeronautics and Space

Administration。

4.spacecraft Cassini：卡西尼号探测器，以出生于意大利的法国天文学家卡西尼的名字命名，其任务是环绕土星飞行，对土星及其大气、光环、卫星和磁场进行深人考察。1997 年10 月15日，重六吨的“卡西尼”号星际探测器被发射飞往土星的轨道。这是上世纪发射的最后一艘行星际探测的大飞船。“卡西尼”号用了将近七年时间，在2004 年7月1日飞达土星轨道。

5.bugs：微生物。非正式口语表达，所以使用了引号。

6.Kelvin：可翻译成“绝对温度”。Kelvin Scale ，绝对温标，开氏温标，是由Kelvin 勋爵于19世纪中叶发明的温度计量方法，其零度相当于摄氏一273. 15" C ，被认为是宇宙中最低温度。这种温度计量方法多为科学家使用。

7.principal investigator：研究项目负责人

8.rule out：排除……的可能性

To date,scientists have not yet detected this form of life...(paragraph 5)What does"this form of life" refer to?

A:Water-based life. B:Methane-based life. C:Liquid-water-based microorganisms. D:Gas-based life.

Text 1
Back in July 1965, the Mariner Four Space Probe transmitted the first close - up pictures of Mars and convinced many people that Mars was as dead as our own moon. Two later space probes seemed to confirm this.
But then, in 1971, Mariner Nine raise hopes once again that there could be life on the planet--or at least that life might once have existed there. The range of experiments to be conducted were designed by mission scientists such as Chuck Klein:
"It was like shooting blind, so to speak, to be trying to devise experiments to look for evidence of life. And we decide to try to use an instrument which could incorporate many different assumptions about what Martian biology might be like--what the bugs might be like or not like. But the fundamental proposition in each portion of our experiment was to look, over a period of time, for evidence of some process going on which we could attribute to biology."
The scientists controlled the Viking experiments from a distance of almost 100 million kilometers. Cameras took pictures of the area a round the robot landers--in case anything moved into view. No aliens were spotted by the cameras, but other experiments seems to show signs of life.
"Almost everything that we planned began to give us data of some kind--that is to say, it wash’ t like everything was dead. For many weeks, We were goaded by the media, who were terribly excited--they were constantly looking for a headline, you know, ’ .They Found Life ! They Found Life ! Every bit of information that we came up with was squeezed by them to try to put a positive twist on it... We really had to work very hard to maintain our cool and present the data just the way we saw it."
But these apparent signs of life were deceptive. By repeating the experiments and double checking the results, the scientists eventually came to the conclusion that the whole planet was dead and would, in fact, be deadly to living organisms.
Since 1976, there have been no further visits. A probe sent by NASA exploded before reaching the planet last year and it now doesn’ t look as if there’ ll be another Mars visit until the end of the decade.
When we do get back there, will we find something new And what about us Could we ever live on Mars This isn’ t as strange an idea as it sounds according to astronomer Patrick Moorer:
"It’ s fair to say that, from a technical point of view, we could put men on Mars within the next few decades. Whether we actually do so or not depends very much more upon politics and finance than upon sheer science, but I think it could be done. And I’ m quite prepared to believe that by this time in the next century, there will be flourishing colonies upon Mars."

The best title for this passage would be （）

A:Is There Life on Mars B:They Found Life! C:Mars, A Dead Planet in the Space D:Future Colonies on Mars

? ?Scientists say they have discovered hints of alien life on the Saturn’s moon. The discovery of a sort of life was announced after researchers at the US space agency, NASA, analyzed data from spacecraft Cassini, which pointed to the existence of methane-based form of life on Saturn’s biggest moon.
? ?Scientists have reportedly discovered clues showing primitive alien beings are "breathing" in Titan’s dense atmosphere filled with hydrogen.
? ?They argue that hydrogen gets absorbed before hitting Titan’s planet-like surface covered with methane lakes and rivers. This, they say, points to the existence of some "bugs" consuming the hydrogen at the surface of the moon less than half the size of the Earth.
? ?"We suggested hydrogen consumption because it’s the obvious gas for life to consume on Titan, similar to the way we consume oxygen on Earth," says NASA scientist Chris McKay. "If these signs do turn out to be a sign of life, it would be doubly exciting because it would represent a second form of life independent from water-based life on Earth. "
? ?To date, scientists have not yet detected this form of life anywhere, though there are liq-uid-water-based microorganisms on Earth that grow well on methane or produce it as a waste product. On Titan, where temperatures are around 90 Kelvin (minus 290 degrees Farenheit), a methane-based organism would have to use a substance that is liquid as its medium for living processes, but not water itself. Water is frozen solid on Titan’s surface and much too cold to support life as we know it.
? ?Scientists had expected the Sun’s interactions with chemicals in the atmosphere to produce a coating of acetylene on Titan’s surface. But Cassini detected no acetylene on the surface.
? ?The absence of detectable acetylene on the Titan’s surface can very well have a non-bio-logical explanation, said Mark Allen, a principal investigator of the NASA Titan team.
? ?"Scientific conservatism suggests that a biological explanation should be the last choice after all non-biological explanations are addressed," Alien said. "We have a lot of work to do to rule out possible non-biological explanations. It is more likely that a chemical process, without biology, can explain these results. /

What have scientists found about Saturn?

A:They have found methane-based life on Saturn. B:They have found a new moon orbiting Saturn. C:They have found methane-based life on Titan. D:They have found earthlike life on a Saturn’s moon.

? ?Scientists say they have discovered hints of alien life on the Saturn’s moon. The discovery of a sort of life was announced after researchers at the US space agency, NASA, analyzed data from spacecraft Cassini, which pointed to the existence of methane-based form of life on Saturn’s biggest moon.
? ?Scientists have reportedly discovered clues showing primitive alien beings are "breathing" in Titan’s dense atmosphere filled with hydrogen.
? ?They argue that hydrogen gets absorbed before hitting Titan’s planet-like surface covered with methane lakes and rivers. This, they say, points to the existence of some "bugs" consuming the hydrogen at the surface of the moon less than half the size of the Earth.
? ?"We suggested hydrogen consumption because it’s the obvious gas for life to consume on Titan, similar to the way we consume oxygen on Earth," says NASA scientist Chris McKay. "If these signs do turn out to be a sign of life, it would be doubly exciting because it would represent a second form of life independent from water-based life on Earth. "
? ?To date, scientists have not yet detected this form of life anywhere, though there are liq-uid-water-based microorganisms on Earth that grow well on methane or produce it as a waste product. On Titan, where temperatures are around 90 Kelvin (minus 290 degrees Farenheit), a methane-based organism would have to use a substance that is liquid as its medium for living processes, but not water itself. Water is frozen solid on Titan’s surface and much too cold to support life as we know it.
? ?Scientists had expected the Sun’s interactions with chemicals in the atmosphere to produce a coating of acetylene on Titan’s surface. But Cassini detected no acetylene on the surface.
? ?The absence of detectable acetylene on the Titan’s surface can very well have a non-bio-logical explanation, said Mark Allen, a principal investigator of the NASA Titan team.
? ?"Scientific conservatism suggests that a biological explanation should be the last choice after all non-biological explanations are addressed," Alien said. "We have a lot of work to do to rule out possible non-biological explanations. It is more likely that a chemical process, without biology, can explain these results. /

Which of the following can replace the title of this passage?

A:Finding of One More Moon of Saturn. B:Titan, a New Satellite Found. C:A different Life Form, a Possibility. D:Earthlike Living Beings Found on Titan.

第三篇"Life Form Found" on Saturn’s Titan Scientists say they have discovered hints of alien life on the Saturn’s moon. The discovery of a sort of life was announced after researchers at the US space agency, NASA, analyzed data from spacecraft Cassini, which pointed to the existence of methane-based form of life on Saturn’s biggest moon. Scientists have reportedly discovered clues showing primitive alien beings are "breathing" in Titan’s dense atmosphere filled with hydrogen. They argue that hydrogen gets absorbed before hitting Titan’s planet-like surface covered with methane lakes and rivers. This, they say, points to the existence of some "bugs" consuming the hydrogen at the surface of the moon less than half the size of the Earth. "We suggested hydrogen consumption because it’s the obvious gas for life to consume on Titan, similar to the way we consume oxygen on Earth," says NASA scientist Chris McKay. "If these signs do turn out to be a sign of life, it would be doubly exciting because it would represent a second form of life independent from water-based life on Earth." To date, scientists have not yet detected this form of life anywhere, though there are liquid-water-based microorganisms on Earth that grow well on methane or produce it as a waste product. On Titan, where temperatures are around 90 Kelvin (minus 290 degrees Fahrenheit), a methane-based organism would have to use a substance that is liquid as its medium for living processes, but not water itself. Water is frozen solid on Titan’s surface and much too cold to support life as we know it. Scientists had expected the Sun’s interactions with chemicals in the atmosphere to produce a coating of acetylene on Titan’s surface. But Cassini detected no acetylene on the surface. The absence of detectable acetylene on the Titan’s surface can very well have a non-biological explanation, said Mark Allen, a principal investigator of the NASA Titan team. "Scientific conservatism suggests that a biological explanation should be the last choice after all non-biological explanations are addressed." Allen said. "We have a lot of work to do to rule out possible non-biological explanations. It is more likely that a chemical process, without biology, can explain these results." Which of the following can replace the title of this passage?

A:A different Life Form, a Possibility. B:Earthlike Living Beings Found on Titan. C:Finding of One More Moon of Saturn. D:Titan, a New Satellite Found.