VOA慢速英语--科学家发现金星可能存在生命的迹象

Scientists Wonder About Possible Sign of Life on Venus

Space scientists have found what could be a possible sign of life in the atmosphere of Venus.

The finding comes from a study published Monday in Nature Astronomy.

The astronomers¹ studied Venus with the James Clerk Maxwell Telescope in Hawaii. They confirmed their observations with the ALMA radio telescope in Chile.

The telescopes found evidence of the chemical phosphine in the thick clouds covering the planet. Phosphine is a poisonous gas. On Earth, it is only associated with life. However, the organizers of the study and other experts agree that the presence of phosphine is not proof of life on another planet.

David Clements helped to prepare a report on the study. He is with Imperial College London. Clements said of the evidence, "It's not a smoking gun." But he added that it may "be suggesting something."

As astronomers look for signs of life outside our solar system, one method is to look for chemicals that result only from biological processes. These processes are known as biosignatures.

After three astronomers met in a bar in Hawaii, they decided³ to look for biosignatures a little closer to Earth – the planet Venus. The three looked for phosphine, a molecule⁴ made up of three hydrogen atoms and a single phosphorous atom.

Phosphine can form only two ways on Earth. It can be created by an industrial process, or it can come from a biological process in animals and microbes that is not well understood. Some scientists consider it a waste product.

Clements said phosphine can be found in the bottom of ponds, the insides of animals like badgers⁵ and in the waste of penguins⁶.

Sara Seager, also involved in the study, is a planetary scientist with the Massachusetts Institute of Technology. She said the astronomers carefully looked at all the possibilities for production of the phosphine: volcanoes, lightning strikes or meteorites⁸ falling into the atmosphere. "...Not a single process we looked at could produce phosphine in high enough quantities to explain our team's findings," she said.

Could life be responsible?

The astronomers debated how life could exist on a planet like Venus, where there is no water and the surface temperature is 425 degrees Celsius⁹.

"Venus is hell. Venus is Earth's evil twin," said Clements.

But Seager noted¹⁰ that 50 kilometers above the planet's surface, in Venus' thick carbon dioxide clouds, it is about room temperature. The clouds are mostly made up of sulfuric acid. But they also contain droplets¹¹ with very small amounts of water.

The scientists asked themselves if the phosphine could be coming from microbes living inside the sulfuric acid droplets. Seager and Clements suggested that, when the droplets fall to the ground, they might dry out but could collect in other droplets and reanimate.

While life is a possibility, several other scientists say more proof is needed.

Cornell University astronomer² Lisa Kaltenegger said the idea of the gas possibly being a sign of a biological process is exciting. But she is not sure life is the only explanation.

Justin Filberto, with the Lunar and Planetary Institute in Houston, told The Associated Press that the levels of phosphine might be explained by volcanoes. He said recent studies that were not considered in the new research suggest that Venus may have far more active volcanoes than scientists had thought. But Clements said that explanation would make sense only if Venus were at least 200 times more active than Earth.

David Grinspoon is an astrobiologist with the Planetary Science Institute. He wrote a book suggesting that life could exist on Venus. Grinspoon was excited, but "cautious" about the new study's finding. It "almost seems too good to be true," he said.

Clements noted that his head tells him there is "probably a 10 percent chance that it's life." But he added, his heart "...wants it to be much bigger because it would be so exciting."

Words in This Story

associated – adj. connected or linked with something else

solar – adj. involving the Sun

bar – n. a place where alcoholic¹³ drinks are served

microbe – n. an extremely small living thing only observed through a microscope

pond – n. a small body of water

meteorite⁷ – n. a rock or larger object that reaches Earth without breaking up in the atmosphere

hell – n. a place of destruction

droplet¹² –n. a very tiny amount of a liquid

1 astronomers   

n.天文学者，天文学家( astronomer的名词复数 )

参考例句：

• Astronomers can accurately foretell the date,time,and length of future eclipses. 天文学家能精确地预告未来日食月食的日期、时刻和时长。 来自《简明英汉词典》
• Astronomers used to ask why only Saturn has rings. 天文学家们过去一直感到奇怪，为什么只有土星有光环。 来自《简明英汉词典》

2 astronomer   

n.天文学家

参考例句：

• A new star attracted the notice of the astronomer.新发现的一颗星引起了那位天文学家的注意。
• He is reputed to have been a good astronomer.他以一个优秀的天文学者闻名于世。

3 decided   

adj.决定了的，坚决的；明显的，明确的

参考例句：

• This gave them a decided advantage over their opponents.这使他们比对手具有明显的优势。
• There is a decided difference between British and Chinese way of greeting.英国人和中国人打招呼的方式有很明显的区别。

4 molecule   

n.分子，克分子

参考例句：

• A molecule of water is made up of two atoms of hygrogen and one atom of oxygen.一个水分子是由P妈̬f婘̬ 妈̬成的。
• This gives us the structural formula of the molecule.这种方式给出了分子的结构式。

5 badgers   

n.獾( badger的名词复数 )；獾皮；（大写）獾州人（美国威斯康星州人的别称）；毛鼻袋熊

参考例句：

• Badgers had undermined the foundations of the church. 獾在这座教堂的地基处打了洞。 来自《简明英汉词典》
• And rams ' skins dyed red, and badgers' skins, and shittim wood. 5染红的公羊皮，海狗皮，皂荚木。 来自互联网

6 penguins   

n.企鹅( penguin的名词复数 )

参考例句：

• Why can penguins live in cold environment? 为什么企鹅能生活在寒冷的环境中？ 来自《简明英汉词典》
• Whales, seals, penguins, and turtles have flippers. 鲸、海豹，企鹅和海龟均有鳍形肢。 来自《现代英汉综合大词典》

7 meteorite   

n.陨石；流星

参考例句：

• The meteorite in Jilin Exhibition Hall is believed to be the largest in the world.吉林展览馆的陨石被认为是世界上最大的。
• The famous Murchison meteorite smashed into the Australian ground in 1969.1969年著名的默奇森陨石轰然坠落在澳大利亚。

8 meteorites   

n.陨星( meteorite的名词复数 )

参考例句：

• Small meteorites have left impact craters all over the planet's surface. 这个行星的表面布满了小块陨石留下的撞击坑。 来自《简明英汉词典》
• One theory about the existence of extraterrestrial life rests on the presence of carbon compounds in meteorites. 地球外存在生命的理论是基于陨星上存在碳化合物质这一事实的。 来自《简明英汉词典》

9 Celsius   

adj.摄氏温度计的，摄氏的

参考例句：

• The temperature tonight will fall to seven degrees Celsius.今晚气温将下降到七摄氏度。
• The maximum temperature in July may be 36 degrees Celsius.七月份最高温度可能达到36摄氏度。

10 noted   

adj.著名的，知名的

参考例句：

• The local hotel is noted for its good table.当地的那家酒店以餐食精美而著称。
• Jim is noted for arriving late for work.吉姆上班迟到出了名。

11 droplets   

n.小滴( droplet的名词复数 )

参考例句：

• Droplets of sweat were welling up on his forehead. 他额头上冒出了滴滴汗珠。 来自辞典例句
• In constrast, exhaled smoke contains relatively large water droplets and appears white. 相反，从人嘴里呼出的烟则包含相当大的水滴，所以呈白色。 来自辞典例句

12 droplet   

n.小滴，飞沫

参考例句：

• The rate of droplet growth under different conditions can be evaluated.可以计算在不同条件下的云滴增长率。
• The test results showed that increasing droplet size was associated with better stability.试验结果表明，增加液滴尺寸将使稳定性提高。

13 alcoholic   

adj.（含）酒精的，由酒精引起的；n.酗酒者

参考例句：

• The alcoholic strength of brandy far exceeds that of wine.白兰地的酒精浓度远远超过葡萄酒。
• Alcoholic drinks act as a poison to a child.酒精饮料对小孩犹如毒药。