Venus is way too hot -- it's got no water.  金星太热——所以没水。

Mars -- dry and arid. It's got no water. 火星——干旱贫瘠，也不会有水。

And beyond Mars, the water in the solar system is all frozen. 在太阳系中比火星更远的地方，水全部冻成了固态的冰。

But recent observations have changed all that.  但是最近的观测改变了这一切。

It's now turning our attention to the right places  现在它把我们的注意力带到了正确的地方，

for us to take a deeper look and really start to answer our life question. 让我们去进一步观察，并且真正开始回答生命的问题。

So when we look out into the solar system, where are the possibilities?  那么，当我们探索太阳系时，生命可能存在于哪里呢？

We're concentrating our attention on four locations.  我们将注意力集中在以下四处：

The planet Mars and then three moons of the outer planets: Titan, Europa and small Enceladus.  火星和更远的三个卫星：泰坦（土卫六），欧罗巴（木卫二）和小小的恩赛拉多斯（土卫二）。

So what about Mars? Let's go through the evidence. 火星到底是什么情况呢？让我们看看证据。

Well, Mars we thought was initially moon-like: full of craters, arid and a dead world. 起初我们以为火星像月亮一样：布满陨石坑，荒凉，没有生命。

And so about 15 years ago, we started a series of missions to go to Mars 大约在15年前，我们开始了一系列登陆火星的任务，

and see if water existed on Mars in its past that changed its geology. 去查看那里过去是否有水存在过，还因此改变了它的地质。

We ought to be able to notice that.  我们应该可以观察得到。

And indeed we started to be surprised right away.  而实际上，我们一开始就很惊讶。

Our higher resolution images show deltas and river valleys and gulleys that were there in the past. 高清图片显示，那里有三角洲，河谷和沟渠，它们过去都曾存在过。