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

For the first time ever, astronomers 1 using the Hubble space telescope have discovered the presence of the organic molecule 2 methane 3 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 gaseous 4 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 molecules 5 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 fingerprint 6. 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 hospitable 7 planet in the future, would really be something exciting and that is the way in which these measurements really are the dress rehearsal 8 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.