NASA on Thursday announced the discovery of Kepler-452b, the most Earth-like planet ever found. Located 1,400 light-years from our planet, NASA called it "Earth 2.0," because it's the first planet discovered in the habitable zone of a G star similar to our sun。

周四，美国国家航空航天局(以下简称为NASA)宣布发现开普勒-452b，是迄今为止与地球最为相近的行星。该行星距离地球1400光年，NASA将其命名为“地球2.0”，因为它是第一颗人类在宜居带里与太阳相似的恒星附近发现的行星。

"We can think of Kepler-452b as an older, bigger cousin to Earth, providing an opportunity to understand and reflect upon Earth's evolving environment," said Jon Jenkins, the Kepler data analysis lead at NASA's Ames Research Center。“

我们可以不妨将开普勒-452b视为地球年纪较大，体积也较大的“老表”。从它身上我们可以了解并反思地球所演变的环境，”NASA艾姆斯研究中心开普勒数据分析的领队琼·詹金斯如是说。

The planet is 5 percent farther away from its star than Earth is to the sun, making for a slightly longer year of 385 days, but gets similar light because its sun is 20 percent brighter than our own。

该行星与其恒星之间的距离要比地球与太阳的距离远上百分之五，因此它一年(公转周期比地球稍长)为385天，但光线与地球相差无几。因为它的恒星亮度要比太阳高百分之二十。

"The sunshine from this star would feel very similar to the sunshine from our star," Jenkins told reporters。

詹金斯告诉记者：“开普勒-452b上的阳光跟我们地球上的阳光感觉是差不多的。”

NASA believes the planet has a mass about five times more massive than Earth's, with a rocky surface below a thicker atmosphere than our own. Gravity would be about twice as strong on Kepler-452b as it is on Earth, NASA said。

NASA认为，该行星的质量大约要比地球的质量大5倍，其岩石表面上空的大气层要比地球的大气层厚许多。而开普勒-452b的引力是地球引力的2倍。

The planet is located in the Kepler-452 system in the constellation Cygnus. Its sun has the same surface temperature as our own, but has a diameter that is 10 percent larger。

该行星位于开普勒-452星系里的天鹅座。它的恒星表面温度与地球一样，但直径要比地球大上百分之十。

While NASA scientists have no idea if Kepler-452b's atmosphere is conducive to life, they do know that there has been plenty of time for organisms to develop。

虽然NASA的科学家们无法确定开普勒-452b的大气环境是否有利于生命的形成，但他们知道在该星球上有足够的时间来形成微生物有机体。

"It's awe-inspiring to consider this planet spent 6 billion years in the habitable zone of its star, which is longer the age of the Earth," Jenkins said. "That is considerable time and opportunity for life to arise somewhere on its surface or oceans if all the necessary conditions for life exist on this planet."

“这颗行星在其恒星的宜居带里存在了60亿年，这可比地球的年龄大多了，想想都觉得令人敬畏，”詹金斯说道，“如果该行星上具备适宜生命存在的所有必备条件，这时间足以让其表面形成生命了。”