The search for other Earth-like planets - Olivier Guyon

寻找想地球的行星 —— Olivier Guyon

Transcriber: Andrea McDonough Reviewer: Bedirhan Cinar

翻译人员: Minji Seo 校对人员: Dong Mao

So as an astronomer,

身为一个天文学家

when I look at the sky with other people,

当我与其他人看着天空

they always ask me,

他们总是问我

"What is your favorite place in the universe?

"宇宙中你最喜欢的地方是什么？

What is your favorite galaxy?

你最喜欢的星系是什么？

What is your favorite planet?"

什么是你最喜欢的星球?"

My answer is

我的答案是

Earth. That's right.

地球 是的

This is a very special place, even for an astronomer.

这是一个很特别的地方 即使对于天文学家来说

We look at a lot of places,

我们看很多地方

but there's only one that we know of in the whole universe

但只有一个 我们在整个宇宙中知道的

that we can live on.

我们可以住在的

It's an amazing planet,

这是一个令人惊异的星球

there is an amazing number of things happening,

很多美好的事情在这发生

some of them, you are hearing about it today.

一些是你们现在在听到的

That's the only place in the universe

这是宇宙中唯一一个

where we know that there is life,

已知的存在生命的地方

so that makes it extremely special.

所以 这使它非常特别

What I'm going to talk to you about

我要跟你谈的

is this great adventure in astronomy that is happening

是天文学上在发生的巨大的冒险

where we are actually actively looking

我们实际上在积极地寻找

for other places like this.

像这样的其他地方

It's impossible to imagine the number of possibilities,

我们很难想象其他的可能性

what happens on those other planets

在那些适合居住的其他行星上

that can be habitable.

发生了什么

So that's what I'm going to tell you about.

这就是我今天要跟你说的

So, the first thing we have to think of

所以 第一件事我们必须要想到的

is, well, what makes a planet habitable?

是什么让一颗行星适合居住？

And, the easiest thing to do

最简单的事情

is to look at our own solar system.

是看看我们的太阳系

We have multiple examples.

我们有好多个例子

The first thing we learn is that size matters.

我们要学习的第一件事是尺寸

We can't have a planet that's too small or too big.

我们不能有一个太小或太大的星球

If we look at a planet that is too small,

如果我们看看一个太小的星球

it doesn't have an atmosphere.

它不会有大气层

The moon, technically not a planet,

月亮 从技术上讲不是星球

but a good example for this,

但是一个好的例子

is too small,

是太小了

it doesn't hold an atmosphere.

它不能有大气层

Jupiter - very, very big -

木星——非常 非常大——

and it actually is mostly composed of gas,

它实际上主要由气体组成

it has no surface you can stand on.

它没有你可以站在的表面

The Earth is just right.

地球是刚刚好的

The second thing that we learned

第二件事 我们要学的

is that the planet has to be

是地球与它的恒星

at the right distance from its star.

之间的正好的距离

If the planet is too close to its star,

如果这颗行星太接近它的恒星

it's too hot.

它会太热了

That's the case for Venus.

这是金星的情况

Here I have a picture that was taken by a spacecraft

我这里有一张图片由航天器采取的

that landed on Venus,

那有在金星上降落

and the surface, although it's rocky and quite familiar to us

虽然它的表面是由我们相当熟悉岩石组成的

compared to Earth,

与地球相比

it's really too hot.

这真的是太热了

At the opposite end, if a planet is too far from the star,

在另一端 如果一颗行星离恒星太远

it is too cold.

它会太冷

That's the case for Mars.

这是火星的情况

So, we need to look for planets

所以 我们需要寻找行星

that are at the right distance from their star

与它们的星之间保持正好的距离

and also of the right size.

而且要有正确的大小

So, one other thing,

所以 还有一件事

you know, you might think, "Oh, this is really hard

你知道 你可能会觉得 "哦 这真的很难

because the planet has to be just right.

因为星球要那么刚刚好

It only happened once in our solar system."

在我们的太阳系中只发生了一次"

But when you look at the sky at night,

但当你看着夜晚的天空

and here's a video that I took actually from Hawaii,

这里是一个在夏威夷拍的视频

a dark place where you can see a lot of stars,

一个黑暗的地方 你可以看到很多明星

the first thing you notice is that there are a lot of stars.

你注意到的第一件事是很多的星星

So, the odds are in our favor,

所以 情况对我们有利

even if a small fraction of the stars

就算一小部分的星星

have habitable planets.

有适合人类居住的行星

There are a lot of stars.

那里有很多星星

On a moonless night, in a dark site,

在月黑风高的晚上 在一个黑暗的站点

if you count the stars in the sky

如果你数天上的星星

and you count five stars per second,

每秒数五颗星星

it would take you 15 minutes to count

你需要15分钟数完

all of the stars in the sky.

天空中的所有的星星

That is a tiny fraction of the stars in our galaxy.

这是我们星系中的一小部分的恒星

If you count all the stars in our galaxy,

如果你数星系中的所有星星，

and you also count at five stars per second,

每秒数五颗星星

it would take you more than 1,000 years

你需要超过一千年的时间

to count all the stars in our galaxy.

去数我们的星系中的所有的星星

And then, if you manage

然后 如果你能

to count the galaxies in the universe,

数宇宙中的星系

if you count five galaxies per second,

如果你每秒数每五个星系

it would take you also more than 1,000 years

你需要超过一千年

to count all of the galaxies in the universe.

数完在宇宙中的所有的星系

So the numbers are just astronomical,

这样只是天文的数字

there's a lot of opportunities for exoplanets.

我们有很多机会找到外行星

There has to be a large number of exoplanets

我肯定有一大批的系外行星存在

along which there are,

除了他们是存在的

on which there could be life.

其中可能会有生命的存在

So this is very exciting.

所以这非常令人兴奋

So let's imagine that maybe only 1 in 100 stars

所以让我们想象一下 只有一百个中一个星星

has the right kind of planet,

有合适的星球

and I think this is pessimistic.

我认为这是悲观的

If you could visit one of those planets per second,

如果你可以每秒访问一个行星

it'll take you sixty years

你需要六十年

to actually visit all of them in our galaxy alone.

去访问在我们星系的每个行星

That's, I think, one second is not enough to study them.

我认为 一秒是不够研究他们的时间

So, there's a few hundred of us in this room.

几百的人在这个房间里

If we divided the task and each of us basically took

如果我们分作任务 基本上每个人需要

a couple of minutes to study each planet,

几分钟去研究每个星球

it would take us a life time to do this.

这样会需要我们一生的时间来执行

Meet back again and tell those amazing stories

下次回来 我可以讲那些我们将会看到的令人惊叹的故事

of what we would have seen

下次回来 我可以讲那些我们将会看到的令人惊叹的故事

in maybe some TED senior event.

也许在一些TED 高级讲座上

So, why is it hard?

那么 为什么难？

Why don't we have pictures of exoplanets with aliens on them?

我们为什么没有系外行星的图片有外星人？

Well, here's an example.

嗯 这有个例子

This is a picture that was taken

这图片是

by the Cassinni spacecraft as it was orbiting Saturn.

由Cassinni航天器在环绕土星时拍摄的

It's actually behind Saturn,

它实际上在土星的背后

so what you see is the sun

所以你看到的是太阳

that is blocked by Saturn.

被土星阻止

And if you look very, in detail,

如果你非常详细地看看

if you have very sharp eyesight,

如果您有非常敏锐的视力

you will see all of us.

您将会看到所有的人

We're all on that picture.

我们都在那张照片上

Here is where we are.

这是我们的现状

Um, so that's what Earth starts to look like

嗯 这是地球的样子

when we look at it from far away.

当我们从很远的地方看

Now, we have to do the same thing around other stars,

现在 我们在其他恒星的周围 要做同样的事情

and the planet is very close to the star.

而且星球很接近星星

So this is zooming in to us.

所以这对我们是在放大

All of us are on that little dot

我们在拍照的时候都是在那个小小的点上

at the time the picture was taken.

我们在拍照的时候都是在那个小小的点上

So, what I work on is inventing optics, tricks to actually do this,

所以我在发明光学与技巧来做到这一点，

to take images of planets around those other stars.

采取围绕行星的恒星的照片

This is my easiest coronagraph.

这是我最简单的冕

We call this optic tricks, "coronagraph".

我们把这光的技巧叫"冕"

This is the easiest one I ever built.

这是所建中最简单的一个

I just put my thumb in front of the sun

我把我的拇指放在太阳前

and then you can see things around it.

然后就可以看到它周围的事物

That's what we're trying to do,

这就是我们要做的

but we need to do it much better

但我们需要比这张照片上我做的更好

than what I did in this picture.

但我们需要比这张照片上我做的更好

And, there are two things we need to do:

我们需要做两件事：

we need a much better eye,

我们需要很多更好的眼睛

call them telescopes,

and we need more fancy, clever ways to do it

叫“望远镜”

我们需要更多华丽 聪明的方式来完成它

than putting a thumb.

比放一个拇指

So as an example, one of the projects I work on

所以作为一个例子 我工作的项目之一

is for the Subaru Telescope,

是斯巴鲁望远镜

which you can see here in this picture.

你可以从这张照片看到它

It's a very large telescope,

这是一个非常大的望远镜

so I replace my eye by a large telescope.

所以这大望远镜取代了我的眼睛

And, the other thing that we do

并且 我们做的事情中也有

is the coronagraph is not just a stupid thumb,

冕 它不只是一个愚蠢的拇指

it's this very complicated thing

它是一种很复杂的东西

that's shown in that picture

该图中所示

that I would love to have time to tell you about.

我有时间的话很想谈论这个东西

Just to give you a sense for size,

为了给你们一个感觉它有多大

this arrow points to a door on the side of the telescope,

此箭头指明望远镜的一扇门

and if you have very sharp eyes,

如果你有非常敏锐的目光

you can see that there is a railing going around the telescope,

你可以看到栏杆绕着望远镜

so it's a really big eye.

它是一个很大的眼睛

So, I think the most exciting thing for me

对我来说最令人兴奋的事情

is actually to look at the night sky,

其实是看看夜晚的天空

to see all these stars and wonder,

看这些所有的星星和奇迹

"Well, are there people on planets around those stars?"

"嗯 还有人在这些恒星周围的行星上?"

Because there must be amazing things happening

因为令人惊异的事情肯定会发生

around those stars that we don't know yet.

在我们还不知道那些星球上

During your life time, we will start

在你的生命中 我们会开始

to actually figure out those things.

找出那些东西

And the most exciting thing for me

而且最令我想想也兴奋的事情 也许是

is to think about, maybe,

而且最令我想想也兴奋的事情 也许是

beings on those stars looking back at our star

从那些星星上回看我们的星星

and wondering the same thing.

并在想同样的事

So I think the future will be extremely exciting

因此 我认为未来会非常令人兴奋

because we are starting to figure out those things

因为我们会开始找出那些东西

and amazing range of possibilities

和惊人的可能性

is, I think, even wider than our imagination.

甚至比我们想象的还要多

Thank you.

谢谢