探尋外星生命新進展 土衛星發現大量液態水

Under an icy crust, one of Saturn's smallest moons harbors a pool of water equal to the largest lakes on Earth, adding to evidence that the frigid outlands of the solar system may be suitable for the chemistry of life, planetary scientists in the U.S. and Italy said Thursday.

美國和意大利行星科學家週四稱，在土星的最小衛星之一土衛二(Enceladus)的一片冰面下方發現了大片液態水，其規模和地球上最大的湖相當。這是太陽系外圍或適宜生命存在的又一證據。

The subsurface lake on the moon Enceladus was revealed by gravity measurements made by the National Aeronautics and Space Administration's Cassini probe, which has been traveling among Saturn's moons for the past decade. The scientists, who reported their work in Science, said the moon has a reservoir of water beneath a sheath of ice 18 to 24 miles thick.

美國國家航空航天局(National Aeronautics and Space Administration, NASA)的“卡西尼”(Cassini)號探測器對土衛二進行重力測量後發現了該片湖水，卡西尼號過去10年中穿越於土星的多顆行星之間。科學家將此次研究結果刊登於《科學》(Science)雜誌，稱土衛二在一片18至24英里（29至39公里）厚的冰面下方存有液態水。

'It is as large as or larger than Lake Superior,' said planetary scientist David Stevenson at the California Institute of Technology, who was part of the research team led by aerospace engineer Luciano Iess at the Sapienza University of Rome.

此次研究小組成員、加州理工學院(California Institute of Technology)行星科學家史蒂文森(David Stevenson)說， 這片湖水至少和蘇比略湖一樣大，甚至可能更大。此次研究由羅馬大學(Sapienza University of Rome)航天工程師耶斯(Luciano Iess)帶領的研究小組進行。

In 2005, the Cassini probe detected water vapor and ice spewing from vents near the moon's South Pole, where the subsurface lake is located. The researchers believe the lake rests directly on a bed of silicate rocks that could leach organic chemicals into the water.

2005年卡西尼號探測到土衛二南極地區附近的孔中噴射出水蒸氣和冰，而這裏正是冰下湖的所在處。研究人員相信這片液態水直接位於硅酸鹽岩石的湖牀上方，其有機化合物或可直接滲入水中。

'It makes the interior of Enceladus an attractive place to look for life,' said astrobiologist Jonathan Lunine at Cornell University in Ithaca, N.Y.

康奈爾大學(Cornell University)天體生物學家路寧(Jonathan Lunine)說，這一發現使得土衛二內部成爲探尋生命的一個更具吸引力的對象。