有史以来第一张土星卫星地图

有史以来第一张土星卫星地图，使它成为外星生命的有力候选

Scientists on Monday unveiled the first global geological map of Saturn’s moon Titan, including vast plains and dunes of frozen organic material and lakes of liquid methane, illuminating an exotic world considered a strong candidate in the search for life beyond Earth.

科学家们于本周一公布了土星的卫星“泰坦”(Titan)的第一幅全球地质图，其中包括广阔的平原、布满冰冻有机物质的沙丘和液态甲烷的湖泊。这幅地图向人们展示了一个被认为是在地球之外寻找生命强有力候选者的奇异世界。

The map was based on radar, infrared and other data collected by NASA’s Cassini spacecraft, which studied Saturn and its moons from 2004 to 2017. Titan, with a diameter of 3,200 miles (5,150 km), is the solar system’s second-biggest moon behind Jupiter’s Ganymede. It is larger than the planet Mercury.

这张地图是根据美国宇航局卡西尼号飞船收集的雷达、红外和其他数据绘制的，该飞船在2004年至2017年对土星及其卫星进行了研究。泰坦直径3200英里(5150公里)，是太阳系仅次于木星木卫三的第二大卫星。它比水星还大。

Organic materials — carbon-based compounds critical for fostering living organisms — play a leading role on Titan.

有机物质——碳基化合物对培养生物至关重要——在泰坦上起着主导作用。

“Organics are very important for the possibility of life on Titan, which many of us think likely would have evolved in the liquid water ocean under Titan’s icy crust,” said planetary geologist Rosaly Lopes of NASA’s Jet Propulsion Laboratory in California.

美国宇航局喷气推进实验室的行星地质学家罗莎莉·洛佩斯说：“有机物对泰坦上生命的可能性非常重要，我们之中有许多人认为，泰坦冰冷外壳下的液态海洋可能发展出生命。”。
 

Reuters

“Organic materials can, we think, penetrate down to the liquid water ocean and this can provide nutrients necessary for life if it evolved there,” added Lopes, who led the research published in the journal Nature Astronomy.

“我们认为，有机物质可以渗透到液态水海洋中，如果在那里进化的话，将可以为生命提供必要的营养。”洛佩斯补充说，他领导了发表在《自然天文学》杂志上的这项研究。

On Earth, water rains down from clouds and fills rivers, lakes and oceans. On Titan, clouds spew hydrocarbons like methane and ethane — which are gases on Earth — in liquid form due to the moon’s frigid climate.

在地球上，水从云层中落下，充满了河流、湖泊和海洋。在泰坦上，由于月球寒冷的气候，云层会喷出甲烷和乙烷等碳氢化合物——它们是地球上的气体——以液态形式存在。

Rainfall occurs everywhere on Titan, but the equatorial regions are drier than the poles, said study co-author Anezina Solomonidou, a European Space Agency research fellow.

欧洲航天局研究员、研究合著者阿尼齐娜·索洛莫尼杜(Anezina Solomonidou)说，泰坦上到处都有降雨，但赤道地区比两极干燥。

Plains (covering 65 percent of the surface) and dunes (covering 17 percent of the surface) made up of frozen bits of methane and other hydrocarbons dominate Titan’s mid-latitudes and equatorial regions, respectively.

由冰冻的甲烷和其他碳氢化合物组成的平原(覆盖65%的地表)和沙丘(覆盖17%的地表)分别控制着泰坦的中纬度和赤道地区。

Titan is the only solar system object other than Earth boasting stable liquids on the surface, with lakes and seas of full of methane being major features at its polar regions. Hilly and mountainous areas, thought to represent exposed portions of Titan’s crust of water ice, represent 14 percent of the surface.

泰坦是除了地球以外唯一一个表面有稳定液体的太阳系天体，其极地地区的主要特征是充满甲烷的湖泊和海洋。泰坦水冰外壳裸露部分的丘陵和山区占地表的14%。

“What is really fun to think about is if there are any ways that those more complex organics can go down and mix with water in the deep icy crust or deep subsurface ocean,” JPL scientist and study co-author Michael Malaska said.

喷气推进实验室的科学家、该研究的合著者迈克尔·玛拉斯卡说:“真正有趣的是，这些更复杂的有机物是否能以某种方式进入到深海的冰壳或深海的地下，并与水混合。”

The map was created seven years before the US space agency is set to launch its Dragonfly mission to dispatch a multi-rotor drone to study Titan’s chemistry and suitability for life. Dragonfly is scheduled to reach Titan in 2034.

这张地图是在美国航天局(US space agency)准备发射蜻蜓任务(Dragonfly mission)的七年前绘制的，目的是派遣一架多旋翼无人机来研究泰坦的化学性质和对生命的适应性。蜻蜓计划将于2034年到达泰坦。