Aomawa Shields: How we'll find life on other planets | TED

翻译人员: Hong Li 校对人员: wenli liu

I am in search of another planet in the universe where life exists.

我正在宇宙中寻找另一颗有生命的行星。

I can't see this planet with my naked eyes

靠肉眼肯定看不到，

or even with the most powerful telescopes

即使借助如今最强大的望远镜

we currently possess.

也看不到。

But I know that it's there.

但我坚信它的存在。

And understanding contradictions that occur in nature

了解自然界的矛盾法则，

will help us find it.

能帮助我们找到它。

On our planet,

在我们地球上，

where there's water, there's life.

哪里有水，哪里就有生命。

So we look for planets that orbit at just the right distance

因此我们将目光锁定在 那些与恒星的距离

from their stars.

正合适的行星。

At this distance,

这一距离，

shown in blue on this diagram for stars of different temperatures,

在这张示意图中以蓝色表示， 根据恒星温度的高低而不同，

planets could be warm enough for water to flow on their surfaces

能保证行星足够温暖, 使水保持液态，

as lakes and oceans

形成湖泊和海洋，

where life might reside.

就有可能孕育生命。

Some astronomers focus their time and energy on finding planets

一些天文学家将时间和精力 投入到搜寻那些

at these distances from their stars.

与其所围绕恒星的距离 在这一范围内的行星。

What I do picks up where their job ends.

而我的工作紧随其后。

I model the possible climates of exoplanets.

我建立这些系外行星的气候模型。

And here's why that's important:

这项工作很重要：

there are many factors besides distance from its star

因为要决定行星上是否有生命存在，

that control whether a planet can support life.

除了与恒星的距离外， 还有许多其他因素。

Take the planet Venus.

以金星为例。

It's named after the Roman goddess of love and beauty,

它以罗马（神话中） 爱和美之女神的名字命名，

because of its benign, ethereal appearance in the sky.

因为它看起来如此优雅而美丽。

But spacecraft measurements revealed a different story.

然而宇宙飞船测量的结果 完全不是这么回事。

The surface temperature is close to 900 degrees Fahrenheit,

金星表面的温度接近900华氏度，

500 Celsius.

也就是500摄氏度。

That's hot enough to melt lead.

这温度足以融化铅。

Its thick atmosphere, not its distance from the sun, is the reason.

原因并不在于它与太阳的距离， 而在于它厚厚的大气层。

It causes a greenhouse effect on steroids,

金星的大气层引发的温室效应，

trapping heat from the sun and scorching the planet's surface.

将来自太阳的热量牢牢锁住， 将金星地表变成一片焦土。

The reality totally contradicted initial perceptions of this planet.

这与我们之前对金星的想象 完全不一样。

From these lessons from our own solar system,

我们太阳系的这个例子告诉我们，

we've learned that a planet's atmosphere

行星的大气层

is crucial to its climate and potential to host life.

对于其气候特点和 能否孕育生命至关重要。

We don't know what the atmospheres of these planets are like

我们无法了解那些（可能孕育生命的） 行星的大气情况，

because the planets are so small and dim compared to their stars

因为跟它们围绕的恒星相比， 它们又小又暗，

and so far away from us.

而且离我们非常遥远。

For example, one of the closest planets that could support surface water --

比如，离我们最近的， 可能有液态水存在的行星之一，

it's called Gliese 667 Cc --

叫做“格利泽667Cc”——

such a glamorous name, right, nice phone number for a name --

多美的名字啊，对吧， 做电话号码应该不错——

it's 23 light years away.

离我们23光年。

So that's more than 100 trillion miles.

也就是超过100万亿英里。

Trying to measure the atmospheric composition

想要在一颗系外行星 从它的主恒星前经过时，

of an exoplanet passing in front of its host star is hard.

测量它的大气成分太难了。

It's like trying to see a fruit fly

就好比要看清一只

passing in front of a car's headlight.

从车头灯前飞过的果蝇一样。

OK, now imagine that car is 100 trillion miles away,

而且，这辆车还远在100万亿英里之外，

and you want to know the precise color of that fly.

你还想看清这只果蝇的颜色。

So I use computer models

因此我用计算机建模，

to calculate the kind of atmosphere a planet would need

来计算一颗行星要形成 适宜水和生命存在的气候，

to have a suitable climate for water and life.

需要何种大气类型。

Here's an artist's concept of the planet Kepler-62f,

这是一张“开普勒62f”行星的概念图，

with the Earth for reference.

旁边是用来做对比的地球。

It's 1,200 light years away,

它距离我们1200光年，

and just 40 percent larger than Earth.

体积只比地球大40%。

Our NSF-funded work found that it could be warm enough for open water

我们的研究——由国家科学基金会资助—— 发现它温度适宜，可能存在液态水，

from many types of atmospheres and orientations of its orbit.

它的大气拥有多种成分， 还有它的公转轨道（都可能证明这一点）。

So I'd like future telescopes to follow up on this planet

因此我希望未来的望远镜 能继续观测这颗行星，

to look for signs of life.

寻找生命存在的迹象。

Ice on a planet's surface is also important for climate.

行星表面的冰层对于气候同样重要。

Ice absorbs longer, redder wavelengths of light,

冰能吸收波长较长、更靠近红端的光，

and reflects shorter, bluer light.

反射波长较短、更靠近蓝端的光。

That's why the iceberg in this photo looks so blue.

这就是为什么这张照片里的 冰山看起来这么蓝。

The redder light from the sun is absorbed on its way through the ice.

阳光里偏红的光在穿过冰层时被吸收。

Only the blue light makes it all the way to the bottom.

只有蓝色的光一路走到底。

Then it gets reflected back to up to our eyes

然后反射到我们的眼睛里，

and we see blue ice.

我们就看到了蓝色的冰。

My models show that planets orbiting cooler stars

我的模型显示，恒星温度越低， 其行星反而更温暖，

could actually be warmer than planets orbiting hotter stars.

恒星温度越高， 其行星反而更寒冷。

There's another contradiction --

这又是一个矛盾之处——

that ice absorbs the longer wavelength light from cooler stars,

冰层吸收来自温度较低恒星 发出的波长较长的光，

and that light, that energy, heats the ice.

而这些光，这些能量，又加热了冰层。

Using climate models to explore

运用气候模型

how these contradictions can affect planetary climate

来研究这些矛盾， 看它们如何影响行星的气候，

is vital to the search for life elsewhere.

对于寻找地外生命至关重要。

And it's no surprise that this is my specialty.

而我命中注定要从事这个行业。

I'm an African-American female astronomer

我是一名非裔美籍女天文学家，

and a classically trained actor

也是受过古典艺术训练的演员，

who loves to wear makeup and read fashion magazines,

我喜欢化妆，喜欢时尚杂志，

so I am uniquely positioned to appreciate contradictions in nature --

所以上帝派我来理解这些矛盾——

(Laughter)

（笑声）

(Applause)

（掌声）

... and how they can inform our search for the next planet where life exists.

并利用它们来寻找 下一个有生命的行星。

My organization, Rising Stargirls,

我成立的“新星女孩”组织，

teaches astronomy to middle-school girls of color,

通过戏剧、写作和视觉艺术的方式，

using theater, writing and visual art.

向非白人女中学生传授天文学知识。

That's another contradiction -- science and art don't often go together,

这也是一对矛盾—— 科技和艺术看起来不同路，

but interweaving them can help these girls bring their whole selves

但两者的交融可以 帮助这些姑娘们实现自我，

to what they learn,

学有所成，

and maybe one day join the ranks of astronomers

也许有一天她们也能成为 那些充满矛盾的

who are full of contradictions,

天文学家中的一员，

and use their backgrounds to discover, once and for all,

运用自身所学，彻底证明

that we are truly not alone in the universe.

我们在茫茫宇宙中并不孤独。

Thank you.

谢谢大家。

(Applause)

（掌声）