VOA常速英语2008年-Astronomers Discover Life-Giving Molecule In Ne

By Jessica Berman
Washington
19 March 2008

For the first time ever, astronomers¹ using the Hubble space telescope have discovered the presence of the organic molecule² methane³ in the atmosphere around a planet outside our solar system. While astronomers say there's no chance that life exists on the exosolar planet, methane is essential for life, opening up the possibility that there could be life somewhere else in the universe. VOA's Jessica Berman reports.

The planet where the methane was discovered is called HD189733b in a solar system that astronomers say is approximately 63 light years from our own.

A light year is the distance that it takes light to travel in one year.

Mark Swain made the discovery in observations at the US National Space Administration's Jet Propulsion Laboratory in Pasadena, California.

In a teleconference with reporters, Swain said there are 270 so-called exoplanets outside of our solar system and this is the first time astronomers have evidence of a chemical compound in the atmospheres around any of them.

Swain said HD189733b is an extremely hot gaseous⁴ planet like Jupiter that circles its parent star in an orbit of a little over two days.

For this reason, Swain said the atmosphere is so hot there's no chance of life on the planet as we know it. But under the right circumstances, he said methane is important for life.

"Methane together with a few other molecules⁵ and under the right conditions can form amino acids which are the building blocks of life," said Mark Swain.

Astronomers made their discovery using the exoplanet's orbit around its star. As HD 189733b moved in front on the sun, Hubble took pictures of the sheer skirt of the atmosphere along the planet's edge.

Swain explained that visible light is made up of many colors and each molecule absorbs a particular color, what he calls its fingerprint⁶. Swain said methane was discovered when Hubble detected the organic molecule's fingerprint.

"The methane, if we were able to detect it on a more hospitable⁷ planet in the future, would really be something exciting and that is the way in which these measurements really are the dress rehearsal⁸ for what we look forward to doing in the future," he said.

Sara Seager is an exoplanetary scientist at the Massachusetts Institute of Technology in Cambridge.

"This is not like simply pointing your camera at the Boston skyline, for example, and snapping a few photos," she said. "The Hubble space telescope was never designed to make measurements like this. This is really pushing the telescope to its limit."

This discovery of organic methane in a distant solar system is reported in the journal Nature.

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 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。

3 methane   

n.甲烷，沼气

参考例句：

• The blast was caused by pockets of methane gas that ignited.爆炸是由数袋甲烷气体着火引起的。
• Methane may have extraterrestrial significance.甲烷具有星际意义。

4 gaseous   

adj.气体的，气态的

参考例句：

• Air whether in the gaseous or liquid state is a fluid.空气，无论是气态的或是液态的，都是一种流体。
• Freon exists both in liquid and gaseous states.氟利昂有液态和气态两种形态。

5 molecules   

分子( molecule的名词复数 )

参考例句：

• The structure of molecules can be seen under an electron microscope. 分子的结构可在电子显微镜下观察到。
• Inside the reactor the large molecules are cracked into smaller molecules. 在反应堆里，大分子裂变为小分子。

6 fingerprint   

n.指纹；vt.取...的指纹

参考例句：

• The fingerprint expert was asked to testify at the trial.指纹专家应邀出庭作证。
• The court heard evidence from a fingerprint expert.法院听取了指纹专家的证词。

7 hospitable   

adj.好客的；宽容的；有利的，适宜的

参考例句：

• The man is very hospitable.He keeps open house for his friends and fellow-workers.那人十分好客，无论是他的朋友还是同事，他都盛情接待。
• The locals are hospitable and welcoming.当地人热情好客。

8 rehearsal   

n.排练，排演；练习

参考例句：

• I want to play you a recording of the rehearsal.我想给你放一下彩排的录像。
• You can sharpen your skills with rehearsal.排练可以让技巧更加纯熟。