评论
打印
Jupiter could be considered an independent solar system, only in miniature form.
木星可被视为一个独立的太阳系，微缩版的太阳系。
The gas giant has the same basic ingredients as the sun and is surrounded by dozens of geologically diverse moons.
这颗气态巨星与太阳有着相同的基本成分，其周围也有数十颗地质多样的卫星。
Out of the 79 confirmed surrounding Jupiter, four ancient moons have astronomers really excited
目前已经证实的就有79颗。其中有4颗令天文学家们格外兴奋，
because they offer up some of the most distinctive geology in the solar system,
因为这4颗古老的卫星有着太阳系最为独特的一些地质特征，
including clues of deep, subsurface oceans that could be home to life.
比如表明可能存在能够变成生命家园的次表层深海的线索。
The Galilean moons are named after Galileo Galilei, who first observed them in 1610.
伽利略卫星是以伽利略的名字命名的，因为最初是伽利略于1610年首次观测到这些卫星的。
Io, Jupiter’s closest Galilean moon,
距离木星最近的伽利略卫星“木卫一”的不寻常之处在于
is unusual because its composition is closer in comparison to the terrestrial planets than the icy bodies that surround it.
就组成成分而言，它比它周围剩下的那些冰体卫星更接近于类地行星。
Io is also the most volcanically active body known in the solar system with over 400 active volcanoes.
有着400多座活火山的木卫一也是这一微缩太阳系中已知的、最活跃的火山体。
This is due to the internal heating produced by the pulling and stretching effect of Jupiter's gravity
这是因为木卫一在绕着木星公转时，木星引力和体积较小的临近卫星对木卫一的来回拉扯
and smaller neighboring moons on Io as it orbits Jupiter.
引起了木卫一内部温度升高所致。
That same tug-of-war heating effect is the reason why some astronomers believe
同样的拔河效应也是一些天文学家认为木星的二号伽利略卫星上
that Jupiter’s second Galilean moon is home to a deep subsurface ocean up to twice the volume of Earth's oceans.
有着一个体积足足为地球海洋两倍的次表层深海的原因。
Unlike Io, Europa has an icy surface, but below it,
与木卫一不同，木卫二是冰面，但天文学家们认为，
astronomers think there may be a salty ocean that could harbor life-bearing chemistry, including organic molecules.
冰面下可能有一个咸水海，那里可能蕴藏着有机分子等能孕育生命的化学物质。
When Europa swings by Jupiter on an elliptical orbit, gravitational tidal forces stretch and flex the sides of the moon,
当木卫二在椭圆轨道上绕着木星公转时，引力潮汐力会导致其表面被拉伸和弯曲，
creating internal friction that essentially heats the moon from the inside out.
从而产生内摩擦，让这颗卫星从内到外升温。
Using its Europa Clipper spacecraft in the 2020s,
美国宇航局(NASA)计划在2020~2029年间使用“木卫二快艇号”，
NASA plans to get a closer look at the moon in order to confirm the existence of a potential ocean.
对该卫星进行更近距离的观察，以确认上面是否真的有海洋存在。
Europa’s neighbor, Ganymede, is also believed to have an ocean hidden under its thick icy shell.
木卫二的邻居，木卫三，也被认为其厚厚的冰层下隐藏着海洋。
The moon’s magnetic field may be affected by an electrically conducting layer from within,
这一卫星的磁场可能受到了内部导电层的影响，
which hints at the existence of a liquid saltwater ocean.
预示着其冰面下可能存在液态咸水海。
But Ganymede’s distance from Jupiter means there’s a weaker tidal force at play,
但木卫三距离木星较远，这就意味着作用在它上面的潮汐力较小，
so it’s less likely that liquid water is present.
所以存在液态水的可能性不大。
The moon is the only one in the solar system known to have a magnetosphere,
不过，木卫三是木星这一微缩太阳系中已知唯一存在磁圈，
protecting its surface from harmful radiation and solar wind.
能够保护其表面免受有害辐射和太阳风伤害的星球。
As Jupiter’s largest moon, Ganymede would be considered a planet if it were orbiting the Sun.
作为木星最大的卫星，如果绕太阳运行，木卫三将可被视为一颗行星。
Out of all four Galilean moons, Callisto is the farthest from Jupiter.
在所有四颗伽利略卫星中，木卫四是离木星最远。
The moon is purported to be one of the most heavily cratered objects in the solar system.
据说，木卫四是木星太阳系中陨石坑最多的天体之一。
With some impact basins expanding to about 2,600 kilometers across,
部分陨石坑足足有近2600公里宽，
these craters could teach us a lot about the formation of our early solar system,
这些陨石坑可以告诉我们很多有关早期的太阳系的信息，
as astronomers believe its surface hasn’t changed in over four billion years.
因为天文学家认为，它的表面已经有40亿年没有发生过变化了。
Unmanned spacecraft have been conducting flybys of the Galilean moons for decades
数十年来，无人驾驶宇宙飞船一直在绕着这几颗伽利略卫星飞行，
and findings from these missions suggest an even greater presence of water.
这些任务得到的发现表明，可能存在的水比我们预想的还要多。
Along with NASA’s Europa Clipper,
和美国宇航局的木卫二快艇号一起，
the European Space Agency’s JUpiter ICy moons Explorer, aka JUICE,
欧洲航天局的“木星冰卫星探测器”，又名“JUICE”(果汁)，
will gain a deeper understanding of the moons’ mysterious properties.
将对这一卫星的神秘属性有更深入的了解。
But getting to these moons will be no small feat
但能到达这些卫星上就已经是一个不小的壮举了，
since the craft will need to slingshot around the Sun
因为飞船需要先绕太阳飞行
and then travel about 800 million kilometers before being caught by Jupiter’s massive gravitational pull.
然后在被木星巨大的引力捕获之前飞行大约8亿公里。
If the spacecraft can survive this arduous journey
如果宇宙飞船成功渡过这段艰难的旅程
and manage to generate enough energy to travel between the moons,
还设法制造了足够的能量飞到了这些卫星之间，
astronomers will gain an unparalleled glimpse into what lies beneath their surfaces,
天文学家们就能以前所未有的视角看到这些卫星次表面的东西，
which could even result in the discovery of the first forms of life beyond Earth.
甚至可能因此发现第一种地外生命形态。
Space Crafts takes you through the depths of the cosmos,
“宇宙飞船系列”能带你穿越宇宙的深处，
explaining bizarre astronomical phenomena and crazy plans for future exploration.
解释奇异的天文现象，管窥未来探索的疯狂计划。
In this episode, we explain how an advanced civilization could harness the total energy of a star.
在这一集中，我们将解释一个先进的文明是如何获取某恒星上的所有能量的。
Thanks for watching Seeker!
感谢收看“《科学探索之旅》!
Don’t forget to subscribe.
别忘了订阅喔。
