Another Earth?

　　另一個(gè)地球?

　　Home away from home

　　遠(yuǎn)離家鄉(xiāng)的家

　　The existence of the most Earthlike planet yet has just been confirmed

　　類(lèi)地球行星的存在已剛被確認(rèn)

　　ONE of the more memorable slogans to come out of the climate-change talks in Durban over the past few days is: there is no planet B . But what if there were? Over the past couple of decades astronomers have logged thousands of so-called exoplanets worlds which orbit stars other than the sun. On December 5th the scientists in charge of Kepler, a space telescope designed to look for such planets, confirmed their instrument s discovery of its first Earthlike world. It is dubbed, rather unromantically, Kepler 22b.

　　在過(guò)去幾天的Durban氣候變化會(huì)談上提出的較難忘的口號(hào)之一就是 沒(méi)有星球B ，但是如果有呢?在過(guò)去的幾十年內(nèi)，天文學(xué)家記載了數(shù)以千計(jì)的所謂的 外行星 ---饒?zhí)?yáng)以外的星球軌道運(yùn)行的宇宙。12月5號(hào)，負(fù)責(zé)開(kāi)普勒號(hào)的科學(xué)家確認(rèn)他們的儀器發(fā)現(xiàn)了第一個(gè)類(lèi)地球星體，開(kāi)普勒號(hào)是專(zhuān)門(mén)為尋找這樣的類(lèi)地球星體而設(shè)計(jì)的太空望遠(yuǎn)鏡。

　　The existence of this planet, which circles a star 600 light-years away, in the constellation of Lyra, had previously been suspected. Kepler, which belongs to NASA, America s space agency, works by observing dips in a star s brightness as a planet passes in front of it. It flags likely looking reductions as candidate planets , of which Kepler 22b was one. But three passes are needed to confirm a planet s existence, and Kepler 22b has now passed this test. Crucially, it orbits well within its star s Goldilocks zone : neither too close nor too far away for liquid water to exist on its surface.

　　存在這么一個(gè)行星，它環(huán)繞天琴座星系中一顆600光年遠(yuǎn)的恒星運(yùn)行，之前被懷疑的不存在，開(kāi)普勒號(hào)，隸屬于美國(guó)國(guó)家航空與宇宙航行局，即美國(guó)航天局，它通過(guò)觀察當(dāng)行星通過(guò)時(shí)恒星光亮度的變化來(lái)工作。它標(biāo)識(shí)顯現(xiàn)的光度弱化可能為候選行星，開(kāi)普勒22b就是一個(gè)。但是一個(gè)行星的確認(rèn)需要通過(guò)三個(gè)檢測(cè)，開(kāi)普勒22b現(xiàn)在已經(jīng)通過(guò)檢驗(yàn)。最重要的是，他環(huán)繞著其恒星的 適居帶 很好地運(yùn)行;不會(huì)太近也不太遠(yuǎn)液體水可能存在在上面。

　　It joins two other Earthlike planets-Gliese 581d and HD 85512 b-discovered by another instrument within the past few years. In truth, the term Earthlike is a stretch. Kepler 22b has a radius 2.4 times that of Earth, and if it is made from roughly the same stuff its surface gravity will also be about 2.4 times as strong. But NASA s astronomers remain unsure whether it is predominantly gaseous, liquid or solid.

　　它加入了另外兩個(gè)類(lèi)地球行星Gliese 581d 和HD 85512 b在過(guò)去的幾年里被另外的儀器發(fā)現(xiàn)的。事實(shí)上， 類(lèi)地球行星 這個(gè)詞言過(guò)其實(shí)，Kepler 22b半徑是地球的2.4倍，如果它和地球的組成大致相同，它的表面引力也將大約高達(dá)地球引力的2.4倍。但是美國(guó)國(guó)家航天與宇宙航行局的天文學(xué)家仍不能確定它主要是氣體的、液體的或是固體的。

　　Nevertheless, Kepler 22b is the most promising exoplanet yet found. Unlike the others, which skirt the edges of their stars Goldilocks zones, Kepler 22b orbits comfortably within its own. NASA s researchers reckon its surface temperature is about 22C, compared with 15C on Earth. Its parent star is similar to the sun, again unlike those of the other two candidates, both of which orbit cooler, dimmer stars. Indeed Gliese 581d s parent is a red dwarf-the tiniest stellar species. That means its Goldilocks zone is so close to it that the planet may be tidally locked, as the moon is to the Earth. If that were the case, one side of Gliese 581d would be permanently lit while the other experienced unending darkness.

　　然而，Kepler 22b 是目前發(fā)現(xiàn)的最有希望的外行星。不像其他行星不在恒星的 適居帶 ，Kepler 22b 在它的 適居帶 舒適地運(yùn)行。美國(guó)國(guó)家航空與宇宙航行局的研究人員通過(guò)與地球表面溫度15C比較，估算出它表面的溫度大概是22C。它的母恒星與太陽(yáng)相似，這又與其他兩個(gè)候選外行星不同，其他兩個(gè)候選外行星都環(huán)繞較冷的、較昏暗的恒星運(yùn)行。Gliese 581d的母恒星確實(shí)是一個(gè)紅矮星---最小的星系。那意味著 適居帶 非常接近它以至于行星可能被潮汐力鎖住，就像月亮對(duì)于地球一樣。如果是那樣的話，Gliese 581d的一面將會(huì)是常年光亮的，而另一面將會(huì)是無(wú)盡的黑暗。

　　These three potentially habitable exoplanets may soon be joined by many more. In the two and a half years since its launch, Kepler has spotted 2,326 candidate planets. About 650 others have been discovered by other instruments. That plethora allows astronomers to start drawing conclusions about how common various sorts of planets are. Of Kepler s haul, 9% seem to be of a similar size to Earth ; a further 29% are Super Earths-planets substantially larger than Earth that are nevertheless rocky. Forty-eight of Kepler s unconfirmed candidates look as if they orbit within their stars habitable zones; of those, ten seem to be Earth-sized.

　　很快可能有更多的外行星加入這三個(gè)可能適合居住的外行星中。 Kepler自發(fā)射以來(lái)的2年半里已經(jīng)發(fā)現(xiàn)了2,326候選行星。其他儀器大約發(fā)現(xiàn)了另外650個(gè)行星。大量的行星使天文學(xué)家開(kāi)始得出行星種類(lèi)繁多的結(jié)論。Kepler捕獲的行星中9%大小與地球相似 sustain human colonists. If only a few of Kepler s possible Earthlike planets turn out to be real, that third number is likely to be in the millions.

　　當(dāng)然最終的目標(biāo)是讓天文學(xué)家對(duì)銀河系的行星總數(shù)、確定可以維持生命的行星數(shù)和那些可以維持人類(lèi)殖民者生命的行星比例做出一個(gè)接近可信的估算。如果Kepler類(lèi)地行星中只有很少被證明是真的，第三個(gè)數(shù)可能是數(shù)百萬(wàn)。

　　Such knowledge will mark an historic transition, says Chris Lintott, an astronomer at Oxford University who is giving the Kepler team a hand with the data analysis, since the uncertainties around the question of whether life exists elsewhere will cease to be astronomical and become purely biological . Based on the preliminary data, it looks as if there are numerous suitable planets. The science of exobiology may soon cease to be an oxymoron

　　一位牛津大學(xué)的天文學(xué)家Chris Lintoot說(shuō)這些知識(shí)是歷史轉(zhuǎn)變的標(biāo)志，他對(duì)Kepler團(tuán)隊(duì)給以數(shù)據(jù)分析的援助，從此關(guān)于其他地方是否存在生命問(wèn)題的不確定性將不再是天文學(xué)問(wèn)題，而是變成了純粹的生物問(wèn)題基于這些初始數(shù)據(jù)，似乎有許多合適的行星，外空生物學(xué)將不再是一個(gè)矛盾修飾。

　　Another Earth?

　　另一個(gè)地球?

　　Home away from home

　　遠(yuǎn)離家鄉(xiāng)的家

　　The existence of the most Earthlike planet yet has just been confirmed

　　類(lèi)地球行星的存在已剛被確認(rèn)

　　ONE of the more memorable slogans to come out of the climate-change talks in Durban over the past few days is: there is no planet B . But what if there were? Over the past couple of decades astronomers have logged thousands of so-called exoplanets worlds which orbit stars other than the sun. On December 5th the scientists in charge of Kepler, a space telescope designed to look for such planets, confirmed their instrument s discovery of its first Earthlike world. It is dubbed, rather unromantically, Kepler 22b.

　　在過(guò)去幾天的Durban氣候變化會(huì)談上提出的較難忘的口號(hào)之一就是 沒(méi)有星球B ，但是如果有呢?在過(guò)去的幾十年內(nèi)，天文學(xué)家記載了數(shù)以千計(jì)的所謂的 外行星 ---饒?zhí)?yáng)以外的星球軌道運(yùn)行的宇宙。12月5號(hào)，負(fù)責(zé)開(kāi)普勒號(hào)的科學(xué)家確認(rèn)他們的儀器發(fā)現(xiàn)了第一個(gè)類(lèi)地球星體，開(kāi)普勒號(hào)是專(zhuān)門(mén)為尋找這樣的類(lèi)地球星體而設(shè)計(jì)的太空望遠(yuǎn)鏡。

　　The existence of this planet, which circles a star 600 light-years away, in the constellation of Lyra, had previously been suspected. Kepler, which belongs to NASA, America s space agency, works by observing dips in a star s brightness as a planet passes in front of it. It flags likely looking reductions as candidate planets , of which Kepler 22b was one. But three passes are needed to confirm a planet s existence, and Kepler 22b has now passed this test. Crucially, it orbits well within its star s Goldilocks zone : neither too close nor too far away for liquid water to exist on its surface.

　　存在這么一個(gè)行星，它環(huán)繞天琴座星系中一顆600光年遠(yuǎn)的恒星運(yùn)行，之前被懷疑的不存在，開(kāi)普勒號(hào)，隸屬于美國(guó)國(guó)家航空與宇宙航行局，即美國(guó)航天局，它通過(guò)觀察當(dāng)行星通過(guò)時(shí)恒星光亮度的變化來(lái)工作。它標(biāo)識(shí)顯現(xiàn)的光度弱化可能為候選行星，開(kāi)普勒22b就是一個(gè)。但是一個(gè)行星的確認(rèn)需要通過(guò)三個(gè)檢測(cè)，開(kāi)普勒22b現(xiàn)在已經(jīng)通過(guò)檢驗(yàn)。最重要的是，他環(huán)繞著其恒星的 適居帶 很好地運(yùn)行;不會(huì)太近也不太遠(yuǎn)液體水可能存在在上面。

　　It joins two other Earthlike planets-Gliese 581d and HD 85512 b-discovered by another instrument within the past few years. In truth, the term Earthlike is a stretch. Kepler 22b has a radius 2.4 times that of Earth, and if it is made from roughly the same stuff its surface gravity will also be about 2.4 times as strong. But NASA s astronomers remain unsure whether it is predominantly gaseous, liquid or solid.

　　它加入了另外兩個(gè)類(lèi)地球行星Gliese 581d 和HD 85512 b在過(guò)去的幾年里被另外的儀器發(fā)現(xiàn)的。事實(shí)上， 類(lèi)地球行星 這個(gè)詞言過(guò)其實(shí)，Kepler 22b半徑是地球的2.4倍，如果它和地球的組成大致相同，它的表面引力也將大約高達(dá)地球引力的2.4倍。但是美國(guó)國(guó)家航天與宇宙航行局的天文學(xué)家仍不能確定它主要是氣體的、液體的或是固體的。

　　Nevertheless, Kepler 22b is the most promising exoplanet yet found. Unlike the others, which skirt the edges of their stars Goldilocks zones, Kepler 22b orbits comfortably within its own. NASA s researchers reckon its surface temperature is about 22C, compared with 15C on Earth. Its parent star is similar to the sun, again unlike those of the other two candidates, both of which orbit cooler, dimmer stars. Indeed Gliese 581d s parent is a red dwarf-the tiniest stellar species. That means its Goldilocks zone is so close to it that the planet may be tidally locked, as the moon is to the Earth. If that were the case, one side of Gliese 581d would be permanently lit while the other experienced unending darkness.

　　然而，Kepler 22b 是目前發(fā)現(xiàn)的最有希望的外行星。不像其他行星不在恒星的 適居帶 ，Kepler 22b 在它的 適居帶 舒適地運(yùn)行。美國(guó)國(guó)家航空與宇宙航行局的研究人員通過(guò)與地球表面溫度15C比較，估算出它表面的溫度大概是22C。它的母恒星與太陽(yáng)相似，這又與其他兩個(gè)候選外行星不同，其他兩個(gè)候選外行星都環(huán)繞較冷的、較昏暗的恒星運(yùn)行。Gliese 581d的母恒星確實(shí)是一個(gè)紅矮星---最小的星系。那意味著 適居帶 非常接近它以至于行星可能被潮汐力鎖住，就像月亮對(duì)于地球一樣。如果是那樣的話，Gliese 581d的一面將會(huì)是常年光亮的，而另一面將會(huì)是無(wú)盡的黑暗。

　　These three potentially habitable exoplanets may soon be joined by many more. In the two and a half years since its launch, Kepler has spotted 2,326 candidate planets. About 650 others have been discovered by other instruments. That plethora allows astronomers to start drawing conclusions about how common various sorts of planets are. Of Kepler s haul, 9% seem to be of a similar size to Earth ; a further 29% are Super Earths-planets substantially larger than Earth that are nevertheless rocky. Forty-eight of Kepler s unconfirmed candidates look as if they orbit within their stars habitable zones; of those, ten seem to be Earth-sized.

　　很快可能有更多的外行星加入這三個(gè)可能適合居住的外行星中。 Kepler自發(fā)射以來(lái)的2年半里已經(jīng)發(fā)現(xiàn)了2,326候選行星。其他儀器大約發(fā)現(xiàn)了另外650個(gè)行星。大量的行星使天文學(xué)家開(kāi)始得出行星種類(lèi)繁多的結(jié)論。Kepler捕獲的行星中9%大小與地球相似 sustain human colonists. If only a few of Kepler s possible Earthlike planets turn out to be real, that third number is likely to be in the millions.

　　當(dāng)然最終的目標(biāo)是讓天文學(xué)家對(duì)銀河系的行星總數(shù)、確定可以維持生命的行星數(shù)和那些可以維持人類(lèi)殖民者生命的行星比例做出一個(gè)接近可信的估算。如果Kepler類(lèi)地行星中只有很少被證明是真的，第三個(gè)數(shù)可能是數(shù)百萬(wàn)。

　　Such knowledge will mark an historic transition, says Chris Lintott, an astronomer at Oxford University who is giving the Kepler team a hand with the data analysis, since the uncertainties around the question of whether life exists elsewhere will cease to be astronomical and become purely biological . Based on the preliminary data, it looks as if there are numerous suitable planets. The science of exobiology may soon cease to be an oxymoron

　　一位牛津大學(xué)的天文學(xué)家Chris Lintoot說(shuō)這些知識(shí)是歷史轉(zhuǎn)變的標(biāo)志，他對(duì)Kepler團(tuán)隊(duì)給以數(shù)據(jù)分析的援助，從此關(guān)于其他地方是否存在生命問(wèn)題的不確定性將不再是天文學(xué)問(wèn)題，而是變成了純粹的生物問(wèn)題基于這些初始數(shù)據(jù)，似乎有許多合適的行星，外空生物學(xué)將不再是一個(gè)矛盾修飾。