"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.

Pool Watch

    Swimmers can drown in busy swimming pools when lifeguards fail to notice that they are introuble. The Royal Society for the Prevention of Accidents says that on average 15 people drown in British pools each year, but many more suffer major injury after getting into difficulties. Now a French company has developed an artificial intelligence system called Poseidon that sounds thealarm when it sees someone in danger of drowning.

    When a swimmer sinks towards the bottom of the pool, the new system sends an alarm signal to a poolside monitoring station and a lifeguard"s pager. In trials at a pool in Ancenis, it saved a life with in just a few months, says Alistair McQuade,a spokesman for its maker, Poseidon Technologies.

    Poseidon keeps watch through a network of underwater and overhead video cameras. AI software analyses the images to work out swimmers" trajectories. To do this reliably, it has to tell the difference between a swimmer and the shadow of someone being cast onto the bottom or side of the pool. "The underwater environment is a very dynamic one, with many shadows and reflections dancing around", says McQuade.

    The software does this by "projecting" a shape in its field of view onto an image of the far wall of the pool. It does the same with an image from another camera viewing the shape from a different angle. If the two projections are in the same position, the shape is identified as a shadow and is ignored. But if they are different, the shape is a swimmer and so the system follows its trajectory.

    To pick out potential drowning victims, anyone in the water who starts to descend slowly is added to the software"s "pre-alert" ¹list,says McQuade. Swimmers who then stay immobile on the pool bottom for 5 seconds or more are considered in danger of drowning. Poseidon double-checks that the image really is of a swimmer, not a shadow, by seeing whether it obscures the pool"s floor texture when viewed from overhead. If so, it alerts the lifeguard, showing the swimmer"s location ona poolside screen.

    The first full-scale Poseidon system will be officially opened next week at a pool in High Wycombe, Buckinghamshire. One man who is impressed with the idea is Travor Baylis, inventor of the clockwork radio. Baylis runs a company that installs swimming pools - and he was once an underwater escapologist with a circus. “I say full marks to them if this works and can save lives", he says. But he adds that any local authority spending ~30,000 - plus on a Poseidon system ought to be investing similar amounts in teaching children to swim.

词汇：

pager [ˈpeɪdʒə(r)] 携带式电子呼叫机

trajectory [trə"dʒektərɪ]轨迹

descend [dɪ"send]下降

immobile [ɪ"məʊbaɪl] 不移动的

texture ["tekstʃə(r)]特征，质地

clockwork [ˈklɔkˌwɜ:k] 时钟机构

escapologist [ˌeskəˈpɒlədʒɪst] 擅长从捆扎的绳索中脱身的杂技演员

注释：

1 pre-alert：预先警戒的。the software"s“pre -alert”list：软件的“预警”名单。pre-：是前缀，意思是先于；预先。又如：preadult：成年前的；precancerous：癌症前期的。alert：警戒的，警觉的。

What is required of AI software to save a life?

A:It must be able to swim B:It must keep walking round the pool C:It can distinguish between a swimmer and a shadow D:It can save a life within a few months

All of the following are true about the product life cycle EXCEPT:

A:It is collection of generally sequential, non-overlapping product phase B:The last product life cycle phase for a product is generally the product’s deterioration and deat C:Generally, a project life cycle is contained within one or more product life cycle D:Generally, a project life cycle contains one or more product life cycle

The change in Japanese life - style is revealed in the fact that ______.

A:the young are less tolerant of discomforts in life B:the divorce rate in Japan exceeds that in the U. S. A C:the Japanese endure more than ever before D:the Japanese appreciate the present life

Many people (live) in Tokyo think (life) in a large city (offers) special (advantages).（）

A:live B:life C:offers D:advantages

Some scientists think there may have been life on the Mars in the past because ______.

A:there is no life there now B:there is a large amount of water at the poles C:the Mars may be able to support life in the future D:conditions may have been similar to those on the Earth

There could be life on the Mars in the future if ______.

A:it supported life in the past B:certain gases are used to cool the planet C:the atmosphere can be heated enough to grow simple plants D:the planet’s volcanoes become as active as they were in the past

What can be inferred from the passage about the route to long life?

A:It remains to be studied. B:It has already been discovered. C:Eating more leads to long life. D:Eating less leads to long life.