Water found on a potentially life-friendly alien planet
一颗可能适合生命生存的外行星被科学家发现有水
In a first for astronomers studying worlds beyond our solar system, data from the Hubble Space Telescope have revealed water vapor in the atmosphere of an Earth-size planet. Although this exoplanet orbits a star that is smaller than our sun,it falls within whats known as the stars habitable zone, the range of orbital distances where it would be warm enough for liquid water to exist on a planets surface.
根据哈勃太空望远镜的数据显示，在与地球大小相仿的行星中，发现有一颗行星的大气层存在水蒸气。对于研究太阳系外星球的天文学家来说，这是个史无前例的重大的发现，虽然它围绕的恒星比地球围绕的恒星太阳要小，但它仍处在该恒星的所谓“宜居带”之内一处于这个轨道距离范围内的行星，温度可允许其地表存在液态水。
The discovery, announced this September in two independent studies, comes from years of observations of the exoplanet K2-18b, a super-Earth thats about 111 light-years from our solar system.
这项发现于今年9月由两项研究独立宣布，来自科学家多年来对这颗名为K2-18b地外行星的观测。这颗“超级地球”距离太阳系约111光年。
K2-18bs orbit takes it seven times closer to its star than Earth gets to the sun. But because it circles a type of dim red star known as an M dwarf, that orbit places it in the stars potentially life-friendly zone. Crude models predict that K2-18bs effective temperature falls somewhere between -100 and 116 degrees Fahrenheit, andif it is about as reflective as Earth, its equilibrium temperature would be roughly the same as our home planets.
K2-18b的轨道与其恒星的距离是太阳到地球距离的1/7。但因为它围绕着一颗被称为M型矮星的暗红色恒星旋转，这个轨道仍使它处于这颗恒星的潜在宜居地带。根据粗略的模型预测，K2-18b 的有效温度在华氏-100度到116度之间，而如果它和地球具有大致相等的反射性，它的平衡温度将和我们地球的温度大致相同。
The fact that researchers have detected water on this type of planet bolsters hope for finding habitable worlds beyond our solar system.
研究人员在这类行星上探测到水，这也为人们在太阳系之外寻找可居住世界带来了更多希望。
“This is the only planet right now that we know outside the solar system that has the correct temperature to support water, it has an atmosphere, and it has water in it一making this planet the best candidate for habitability that we know right now,”Angelos Tsiaras, a University College London astronomer and a co-author of one of the two studies, said during a press conference .
伦敦大学学院天文学家、其中一项研究的合著者安热洛斯.齐亚拉斯在新闻发布会上表示：“这是目前所知的太阳系外唯一一颗温度适宜、允许(液态)水存在的行星。它有大气层，也有水，这使得这颗行星成为我们目前已知的最适合居住的行星。”
