VOA慢速英语2018 木星的卫星欧罗巴可最可能有生命（在线收听）

Jupiter’s Moon Europa May Be Top Candidate for Life

A fresh look at old data is giving scientists a new reason to consider Europa, a moon orbiting the planet Jupiter, as a leading candidate in the search for life beyond Earth.

对老数据的一次重新审视让科学家们又有理由将木卫二作为寻找地外生命的重要选择。

The reason: evidence of water from the moon shooting into space.

原因就是找到了来自该卫星的水汽喷向太空的证据。

NASA, the American space agency, noted an unusual shape -- a bend -- in Europa’s magnetic field in 1997. That was the year when NASA’s Galileo spacecraft passed close to the moon. For a time, it was about 200 kilometers above the surface.

美国宇航局提到了1997年木卫二的磁场出现了一次不同寻常的弯曲。这一年，美国宇航局的伽利略号航天器从该卫星近处掠过。该航天器一度距离其表面只有大约200公里。

Scientists reported earlier this month on their reexamination of the Galileo data. They now think this bend in the magnetic field could be explained by an active geyser in an underground ocean. The scientists believe the spacecraft traveled through a plume of water.

科学家们本月早些时候报告了他们对伽利略数据的重新审视。他们目前认为，磁场的这种弯曲可以用地下海洋中的一处活间歇泉来解释。科学家们认为航天器经过了一处羽状水汽。

Elizabeth Turtle is a planetary scientist with the Johns Hopkins University Applied Physics Laboratory. She told reporters that Europa does have a lot of the qualities that are necessary for life was we know it.

伊丽莎白·泰托（Elizabeth Turtle）是约翰霍普金斯大学应用物理实验室的行星科学家。她对记者表示，木卫二确实具有很多我们已知生命需要的特质。

“There’s water. There’s energy. There’s some amount of carbon material. But the habitability of Europa is one of the big questions that we want to understand,” said Turtle.

泰托表示：“那儿有水，有能量，有一定数量的碳物质。但是木卫二的可居住性是我们最想了解的重要问题之一。”

“And one of the really exciting things about detection of a plume is that that means there may be ways that the material from the ocean — which is likely the most habitable part of Europa because it’s warmer and it’s protected … to come out above the ice shell,” she added.

她补充说：“关于探测到羽流最令人兴奋的是，这意味着可能会有海洋物质从冰壳下喷发出来。而海洋可能是木卫二最宜居的地方，因为它更温暖并且受到了保护。”

University of Michigan space physicist Xianzhe Jia led the latest study, which was published in the journal Nature Astronomy.

密歇根大学空间物理学家贾献哲（Xianzhe Jia，音译）领导了这项最新的研究，并发表在《自然天文学》杂志上。

The findings support other evidence of plumes from Europa, whose ocean may contain two times as much water as all of Earth’s oceans. In 2012, NASA’s Hubble Space Telescope collected evidence of ultraviolet radiation which suggests a plume.

这些研究结果支持了来自木卫二羽流的其它证据。木卫二海洋水量可能是地球所有海洋水量的两倍。2012年，美国宇航局的哈勃太空望远镜搜集到的紫外线辐射证据表明存在羽流。

NASA will get a close-up look from a new spacecraft as part of the space agency’s Europa Clipper mission. That spacecraft could be launched as soon as June 2022. The agency says this could provide a chance to examine plumes for signs of life from Europa’s ocean, some of which may be microscopic.

作为“木卫二飞艇任务”一部分，美国宇航局将用新的航天器做一次近距离探测。该航天器可能于2022年6月发射。美国宇航局表示，这可能会给探测羽流寻找木卫二海洋生命迹象提供证据。

Experts consider Europa to be among the top candidates for life in our solar system. But it is not the only one.

专家认为木卫二是太阳系中存在生命的首选之一。但是它不是唯一的。

For example, NASA’s Cassini spacecraft examined plumes from Enceladus, a moon of the planet Saturn. The water from Enceladus’s ocean contained hydrogen from hydrothermal vents, an environment that may have given rise to life on Earth.

例如，美国宇航局的卡西尼号航天器探测了土卫二的羽流。来自土卫二海洋的水汽含有深海热泉的氢气。木卫二的这种环境可能会产生地球上的生命。

Europa is a little smaller than Earth’s moon. Its ocean is buried under about 15 to 25 kilometers of ice. Experts believe the ocean itself to be anywhere from 60 to 150 kilometers deep.

木卫二比月亮略小。它的海洋被埋在大约15到25公里深的冰下。专家认为，海洋本身的深度在60到150公里之间。

I’m Pete Musto.

Words in This Story

data – n. facts or information used usually to calculate, analyze, or plan something

geyser – n. a hole in the ground that shoots out hot water and steam

plume – n. something, such as smoke, steam, or water, that rises into the air in a tall, thin shape

habitability – adj. the ability of a place or location to support life

exciting – adj. causing feelings of interest and enthusiasm

detection – n. the act or process of discovering, finding, or noticing something

journal – n. a magazine that reports on things of special interest to a particular group of people

mission – n. a task or job that someone is given to do

solar system – n. our sun and the planets that move around it

hydrothermal vent(s) – n. an opening in a planet's surface from which naturally heated water issues