[ti:Large Planet May Offer Clues about Atmospheres on Distant Worlds] [by:www.51voa.com] [00:00.00]更多听力请访问51VOA.COM [00:00.14]Scientists have found a rocky, Earth-like planet [00:05.52]that may offer a chance to study other atmospheres. [00:10.61]This kind of research could help the hunt for life outside of Earth. [00:17.46]The researchers said recently that the planet, called Gliese 486 b, [00:25.38]is not itself likely to have life. [00:29.10]Orbiting a star relatively near our solar system, [00:33.65]Gliese 486 b is hot and dry like Venus, [00:40.57]with possible rivers of lava flowing on its surface. [00:44.98]But its nearness to Earth and its physical qualities [00:49.94]make it well- suited for a study of its atmosphere. [00:54.83]Such research will use the next generation of telescopes, [01:00.01]including the James Webb Space Telescope [01:03.86]that the American space agency NASA plans to launch in October. [01:10.15]These telescopes could give scientists data [01:14.19]to study the atmospheres of other exoplanets [01:18.80]- planets beyond our solar system - including ones that may have life. [01:25.24]José Caballero of the Centro de Astrobiología in Spain [01:32.01]was the co-writer of the research that appeared in the journal Science. [01:38.67]Caballero called the new research possibility, [01:42.55]"the Rosetta Stone of exoplanetology." [01:46.80]He was comparing it to the ancient piece of stone [01:50.92]that helped experts understand ancient Egyptian writing. [01:55.74]Scientists have discovered more than 4,300 exoplanets. [02:02.35]Some have been large gas planets similar to Jupiter. [02:07.35]Others have been smaller, rocky Earth-like worlds. [02:12.65]These are considered candidates for having life. [02:16.45]But current scientific instruments tell us little about their atmospheres. [02:22.82]Trifon Trifonov of the Max Planck Institute for Astronomy in Germany [02:30.36]was the lead writer of the research. [02:33.56]Trifonov said an exoplanet needs to have certain qualities [02:38.95]to work well for atmospheric study. [02:42.61]Gliese 486 b is located about 26.3 light years - [02:49.48] the distance light travels in a year - from Earth, or about 9.5 trillion kilometers. [02:57.94]It is among the closest exoplanets. [03:01.63]It orbits a star that is smaller, cooler and less bright than our sun. [03:08.37]Gliese 486 b's mass is 2.8 times greater than Earth's. [03:15.32]The planet orbits very close to its home star. [03:20.13]Its surface temperature is about 430 degrees Celsius [03:25.94]and its surface gravity may be 70 percent stronger than Earth's. [03:31.31]"Gliese 486 b cannot be habitable, [03:36.37]at least not the way we know it here on Earth," Trifonov said. [03:41.24]Still, Gliese 486 b could prove useful [03:46.69]for studying the atmosphere of an Earth-like planet [03:51.09]using the James Webb Space Telescope [03:54.53]and the future Extremely Large Telescope, which is now being built in Chile. [04:01.49]The chemical mixture of an atmosphere [04:04.83]can tell a lot about a planet and its ability to have life. [04:10.14]Cabellero said that what we learn from Gliese 486 b [04:15.98]and other Earth-like planets could help scientists [04:20.45]better understand atmospheres of other exoplanets that may have life. [04:26.35]I'm John Russell. 更多听力请访问51VOA.COM