美宇航局發現最小行星 竟有生命跡象

National Aeronautics and Space Administration (NASA) announced Tuesday that a planet of rock, orbiting extremely close to its host star, has been identified as the smallest ever discovered outside the solar system. It is also the first rocky, or Earth-like planet discovered by Kepler.

美國宇航局週二宣稱已發現目前系外最小、且與主星距離極近的石性行星。這也是美國宇航局空基望遠鏡開普勒所發現的第一顆石性行星，也稱類地行星。

資料圖:美宇航局發現最小系外行星 公轉週期0.84天

Dubbed Kepler-10b, the exoplanet is about 560 light years from Earth. And with 1.4 times the size of Earth, Kepler-10b is more than 20 times closer to its star than Mercury is to the sun, and whips around the star once every 0.84 days.

該系外行星名爲“開普勒-10b”，距離地球約有560光年。其大小是地球的1.4倍，距其主星的距離卻比水星與太陽之間的距離小了20倍之多，而公轉週期也縮短至0.84天。

This makes it impossible for life to exist on the exoplanet, according to NASA. It's so hot that boiled iron and silicates are flowing into the stellar wind, much like a comet's tail.

美國宇航局稱，這種近距離不可能讓“開普勒-10b”上有生命跡象。該星球表面的熱度足以融化鐵和硅酸鹽，被熔物質隨後流入恆星風，宛若彗星尾巴。

Still, the discovery has scientists optimistic about what else Kepler might be able to reveal. "Although this planet is not in the habitable zone, the exciting find showcases the kinds of discoveries made possible by the mission," said Kepler program scientist Douglas Hudgins.

即使如此，該發現還是讓科學家爲之一振，他們期待開普勒能有更多新發現。“儘管這顆行星不在可居住帶，該發現還是讓人興奮無比的，因爲它表明了更多類似發現的可能性，”開普勒項目科學家道格拉斯 哈金斯說道。