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If you listen carefully, you can hear the sound of space nerds everywhere jumping up and down and shrieking with excitement.
如果你仔细听，应该能听到喜爱太空的书呆子们兴奋狂跳尖叫的声音。
Because scientists just announced that they found a giant underground lake on Mars
因为科学家们刚刚宣布他们在火星上发现了一条巨大的地下湖。
This isn't the first time we've found evidence for some type of liquid water on Mars.
这并不是我们第一次在火星上发现某些液态水的证据。
But those were streaks of it, and they only show up seasonally, and we're not even totally sure what they are.
但是那些证据只是一些周期性呈现的条痕，我们甚至无法完全确定这些条痕是什么。
We've never found a permanent body of water on Mars, or anything close to this much of it in one place.
我们从未在火星上发现永恒水体，也没有任何相近的形态。
And best of all, there's a chance that if life exists, or ever existed on Mars, we might find evidence of it in this lake.
但是如果火星上有生命迹象的话，我们或许能在这条河里发现其证据。
In the new paper, published today in the journal Science,
在出版于《科学》杂志的一篇新论文中，
a group of Italian researchers looked at data from MARSIS,
一个意大利研究团队查看了MARSIS中的数据，
an instrument on the European Space Agency's Mars Express orbiter.
MARSIS是欧洲航天局火星快速轨道卫星中的一个仪器。
MARSIS uses radar to look below the surface of Mars.
MARSIS利用雷达检测活性地表以下活动。
It works kind of like the radar we use to detect planes here on Earth,
其运行有点像是我们用于探测星球的雷达，
by sending out radio waves and measuring how they bounce back, you can get an idea of what's out there.
通过传输无线电波，测量无线电波的反弹，我们可以了解那一侧情况如何。
With MARSIS, scientists can also use the data to figure out some of the properties of the stuff the waves passed through and bounced off of.
利用MARSIS，科学家们还能够使用数据弄清无线电波穿过以及反弹物体的性质。
For this study, they looked at three years' worth of observations of Mars's south pole.
为了这项研究，他们观测了三年中火星南极地带值得观测物体。
It's covered in a layer of mostly water ice, but about 1.5 kilometers below the surface,
其大部分被一层水冰覆盖，但是在表面越150米以下，
the waves reflected off of something weirdly bright and shiny, especially compared to the area around it. Something big.
电波反射到了一些怪异明亮闪耀的东西，尤其与周围物体形成了对比。这个东西很大。
Turns out, it was exactly what you'd expect to see
事实证明，如果电波反射的是冰与液态水之间的一条边界的话，
if the waves were reflecting off of a boundary between ice and liquid water.
这种闪耀的东西正是大家所期望看到的。
The researchers looked into a few other possibilities, like that it was a layer of frozen carbon dioxide,
研究人员对几种可能进行观察，比如，这或许是一层冰冻住的二氧化碳，
but when they ran the numbers, liquid water was the only scenario that made sense.
但是当他们进行计算时，液态水是唯一解释的通的可能的情况。
They found that this water stretches across an area about 20 kilometers wide,
他们发现这片水域横跨一个约20千米宽的区域，
and is either in a separate layer or mixed with some sediment in what's possibly the most exciting sludge humanity has ever found.
这要么是一个单独的层面，要么是和一些沉淀物相混合，这是或许是人类所发现的最令人激动的沉淀物。
But no matter what form it takes, that is a ton of liquid water!
但是不论是什么样的形式，这可是大量液态水啊！
Normally, it's way too cold at Mars's poles for water to stay liquid it's thought to be around -68 degrees Celsius over there.
正常情况下，火星两极的水无法保持液态，因为两极温度过于寒冷，一般认为是在零下68摄氏度以下。
So for liquid water to exist, it must be full of salts that lower its melting point so much salt that it's more like brine than water.
所以要水保持液态，那么其中一定含有大量的盐分，这样才能降低其融点，这样的话，其更像是盐水。
Which brings us to the question on everyone's minds:
这使我们想到了一个问题：
What does this discovery mean for the possibility of life on Mars?
对于火星生命存在的可能性而言，这个发现意味着什么呢？
Well, first things first: even if life could survive in this underground lake, that doesn't mean it's there.
好吧，首先，即使在这个地表湖有生命的存在，这也不意味着其就生活在水中。
This is not evidence for life on Mars. But it does raise some fascinating new possibilities.
这并不是火星上存在生命的证据。但是这确实增加了一些新可能性。
Liquid water is essential for life as we know it, which is why practically all of our search for life on other worlds revolves around water.
大家都知道，液态水是生命必要之物，因此我们对于其他星球生命的探索都围绕水边。
We've found evidence for lakes and rivers on Mars,
我们发现了火星上有湖和小溪的证据，
but until now we thought they vanished billions of years ago.
但是直到现在我们还是认为它们早在十亿年就消失了。
So finding a massive underground lake there today changes a lot.
因此，如今火星大片地表湖的发现改变这种观点。
The problem is, the water would be an extremely harsh environment it's full of salts, and freezing cold.
问题是，这里发现的水环境极其恶劣，因为里边含有大量的盐分并且非常冰冷。
Some especially hardy microbes, known as extremophiles,
一些特别耐寒的微生物—极端微生物
can live in places no other life on Earth could survive, but these conditions are even worse.
可以在一些其他地球生物无法适应的环境生存，但是这些情况更加糟糕。
So to learn more about whether life could survive in Mars's underground lake,
所以为了了解生命是否可以在火星地表湖生存，
we turned to Nilton Renno, an astrobiology expert at the University of Michigan.
我们去求教了密歇根大学的天体生物学专家—尼尔顿。
According to Renno, the water is too cold for life as we know it to survive and probably also too salty.
专家表示，上边的水太过寒冷，也太咸了，不适合生命生存。
But that doesn't mean there's definitely no life there.
但是这并不意味着那里绝对不存在生命。
If there's some source of heat below the surface that we don't know about,
如果在我们不知道的地表湖下边有某种热源的话，
it could mean the water is warmer and probably less salty than we think. Maybe to the point that life could survive.
这就意味着水温会高一些并且盐分可能也也没我们想的那么高。或许这样的话，生命可以生存。
The other potential problem is the chemical composition of the salts in the lake.
另一个潜在的问题是湖中盐分的化学成分。
We're not talking table salt here, this stuff is made up of perchlorates,
这里并不是谈论什么食用盐，这里的这种物质由高氯酸盐组成，
chlorine-containing compounds that are toxic to humans. Martian soil is full of them.
这种含氯的混合物对人体有害。火星土壤中就全是这种物质。
So if you ever get a chance to visit Mars's underground lake, do not lick it!
所以如果你有机会去看火星地表湖的话，别舔！
But just because something is toxic to humans doesn't mean it's toxic to all life in the universe!
但是仅仅因为某些对人体有害的物质并不意味着对全宇宙所有生命都是有害的！
In fact, there are microbes here on Earth that actually feed on perchlorates.
事实上，有些地球微生物就靠高氯酸盐活。
Still, unless the water is much warmer and less salty than we think,
话说回来，除非上边的水比我们想的温度要高，盐分要少，
it doesn't look like life could stay alive in Mars's underground lake. Or at least … not right now.
否则生物似乎不可能在火星地表湖中生存。至少...现在不行。
Mars used to be much warmer and wetter than it is today.
曾经的火星比现在更加温暖和潮湿。
And according to Rennó, ancient microbes could be preserved in the water for millions, if not billions of years.
专家表示，古代微生物可以在水中保存百万年。
Which means we now have a fantastic place to search for life on Mars.
这意味着现在我们在火星上有了一个搜寻生命的地方。
Of course, sending a mission to Mars to look for life a kilometer and a half below the surface is easier said than done.
当然，向火星传送使团寻找生命，说的容易啊。
But maybe not impossible!
但是也并非不可能啊！
For more details on how we could look for evidence of life in this underground lake,
更多关于如何在地表湖中搜寻生命的细节，
plus a lot more information about the research behind this discovery,
以及更多关于该项发现背后的信息，
we did a whole separate episode over on SciShow Space because we're THAT excited about this!
请登录SciShow Space观看。
You can go to youtube.com/scishowspace to check it out.
你可以登录youtube.com/scishowspace点击观看。
In the meantime, thanks for watching this special Breaking News episode of SciShow,
同时，感谢收看本期《科学秀即时新闻》，
and don't forget to go to youtube.com/scishow and subscribe!
不要忘记订阅我们的频道！
