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Listen to part of a lecture in an astronomy class.
聽一段天文學課程。
There's been a lot of talk recently about life on Mars, at the level of microorganisms anyway, mainly because of a few important discoveries and inventions.
最近人們經常談論火星上的生命（微生物層次），主要原因是一些重要的發現和發明。
For example, one major discovery was that at one point water was present on Mars.
比如，一個重大發現是火星上有水。
How do we know?
我們是怎么知道的？
Well, in 2004, an exploration robot discovered jarosite there.
2004年，一個探索型機器人在火星上發現了黃鉀鐵礬。
Jarosite is a yellowish brown mineral with a crystalline structure that's also found on Earth.
黃鉀鐵礬是一種黃棕色的礦物質，其晶體結構在地球上也有（相同的結構）。
It contains iron, potassium and hydroxide.
其中有鐵、鉀和氫氧化物。
The interesting thing is that on Earth at least it needs highly acidic water to form.
有趣的是，在地球上，需要酸性很強的水才能形成這種結構。
So we've got water or had it at one point.
所以我們有水，或一度曾有水。
And since most planetary scientists believe that water is essential to life, the presence of jarosite means that one prerequisite for life was once present on Mars.
且由于大多數行星科學家都相信，水是生命之源，有黃鉀鐵礬說明火星曾具備生命的先決條件。
But there's another thing about jarosite.
但黃鉀鐵礬還有另一方面。
One step in its formation on Earth involves microorganisms; they actually speed up the formation of jarosite dramatically.
在地球上，形成黃鉀鐵礬的其中一個步驟要有微生物參與；實際上，微生物能大幅加快黃鉀鐵礬的形成。
Now, theoretically it is possible for jarosite to form without the help of biological life forms.
理論上，在沒有生物生命形式的幫助下，形成黃鉀鐵礬也是有可能的。
But we don't really know for sure if this happens 'cause… well, because every corner of Earth has some form of biological life.
但我們并不肯定這會不會發生，因為……因為地球上的每個角落都有生物生命。
But jarosite on Earth incorporates all kinds of microorganisms into its crystalline structure.
但地球上的黃鉀鐵礬，其晶體結構中包含了各種各樣的微生物。
So it's possible that if the jarosite on Mars was also formed with the help of microorganisms, we might be able to detect remnants of them in the samples we find.
所以，假如火星上的黃鉀鐵礬也是在微生物的幫助下形成的，我們也許能在找到的樣本中檢測到殘余物，這不是沒有可能的事。
And we have instruments now that will enable us to try to do this.
我們現在有設備，能幫助我們做這件事。
For example, there's a new instrument called the micro-fabricated organic analyzer, or M.O.A.
比如，現在有一種新型設備，叫微加工有機分析儀，又稱M.O.A.
The organic analyzer is an amazing tool.
這個有機分析儀是個很棒的工具。
It will be able to collect soil samples and analyze them right there on Mars, pure, untouched samples.
它能直接在火星上采集土壤樣本并進行分析，樣本是純凈的，原封未動的。
It will let us eliminate the risk we would take of contaminating the samples if they were brought back to Earth.
如果把樣本帶回地球，就有污染樣本的風險，但分析儀就能排除風險。
