TEDGlobal 2009
Andrea Ghez: The hunt for a supermassive black hole
安德烈Ghez: 找寻特大的黑洞
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安德烈Ghez用最新的凯克天文望远镜数据向我们展示了这台光学仪器是如何帮助天文学家理解宇宙当中最神秘的物质：黑洞。她说有证据表明在银河系的中心位置可能隐藏着一个特大的黑洞。
Andrea Ghez - Astronomer
Andrea Ghez is a stargazing detective, tracking the visible and invisible forces lurking in the vastness of interstellar space. Full bio
Andrea Ghez is a stargazing detective, tracking the visible and invisible forces lurking in the vastness of interstellar space. Full bio
Double-click the English transcript below to play the video.
00:15
How do you observe something you can't see?
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如何观察那些你看不见的东西？
00:18
This is the basic question of somebody who's interested
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对于那些有兴趣寻找和研究黑洞的人来讲
00:21
in finding and studying black holes.
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这是一个很基本的问题
00:23
Because black holes are objects
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因为黑洞的引力
00:25
whose pull of gravity is so intense
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太大了
00:28
that nothing can escape it, not even light,
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任何物体，甚至光都无法逃脱
00:30
so you can't see it directly.
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所以你用肉眼根本看不见它。
00:32
So, my story today about black holes
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我今天所要说的黑洞
00:35
is about one particular black hole.
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非常特殊。
00:37
I'm interested in finding whether or not
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我很想知道
00:40
there is a really massive, what we like to call
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在我们这个星系是否存在一个巨大的
00:43
"supermassive" black hole at the center of our galaxy.
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我们称之为“特大”的黑洞½
00:46
And the reason this is interesting is that
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有意思的是
00:49
it gives us an opportunity to prove
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这让我们有机会去证实
00:52
whether or not these exotic objects really exist.
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这些奇异的东西是否真正地存在。
00:56
And second, it gives us the opportunity
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再有这也为我们
00:58
to understand how these supermassive black holes
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了解这些特大质量的黑洞
01:01
interact with their environment,
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如何与它们周围环境相互作用
01:03
and to understand how they affect the formation and evolution
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以及了解它们如何影响
01:06
of the galaxies which they reside in.
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它们所处星系的形成和演化提供了很好的机会。
01:09
So, to begin with,
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那么，首先
01:11
we need to understand what a black hole is
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我们需要了解什么是黑洞
01:14
so we can understand the proof of a black hole.
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这样，我们才能找出黑洞存在的证据。
01:16
So, what is a black hole?
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那么，何为黑洞？
01:18
Well, in many ways a black hole is an incredibly simple object,
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呃，从很多方面上讲，黑洞是一个相当简单的物体
01:22
because there are only three characteristics that you can describe:
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因为只需三个特征就可以概括它：™
01:25
the mass,
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质量
01:27
the spin, and the charge.
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旋转和电荷
01:29
And I'm going to only talk about the mass.
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今天，我只讲它的质量。
01:31
So, in that sense, it's a very simple object.
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从这个角度上来说，黑洞就简单了。
01:34
But in another sense, it's an incredibly complicated object
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但从另外一个角度来讲，它又是相当的复杂
01:36
that we need relatively exotic physics to describe,
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复杂到要用很奇特的物理学来描述它，
01:39
and in some sense represents the breakdown of our physical understanding
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但这又在某种程度上说明了我们对宇宙的物理认识
01:43
of the universe.
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很是有限。
01:45
But today, the way I want you to understand a black hole,
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但是，今天，我想让大家这样理解黑洞
01:47
for the proof of a black hole,
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因为我们要证明它的存在，
01:49
is to think of it as an object
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我门把它当作某个物体来看，
01:51
whose mass is confined to zero volume.
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但是却没有体积。
01:54
So, despite the fact that I'm going to talk to you about
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所以现在我向大家介绍的是
01:56
an object that's supermassive,
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质量特别大，
01:59
and I'm going to get to what that really means in a moment,
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但是确切说又像是某个瞬间，
02:01
it has no finite size.
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因为它没有具体的大小。
02:04
So, this is a little tricky.
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现在看来些滑稽了。
02:06
But fortunately there is a finite size that you can see,
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幸运的是，我们还有具体的大小可供参照的，
02:10
and that's known as the Schwarzschild radius.
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那就是施瓦西半径。
02:13
And that's named after the guy who recognized
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这是以发现
02:15
why it was such an important radius.
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这个半径的重要性的人来命名的。
02:17
This is a virtual radius, not reality; the black hole has no size.
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这并不是黑洞的实际半径，因为黑洞并无大小。
02:20
So why is it so important?
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那为什么它如此重要
02:22
It's important because it tells us
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它的重要之处在于告诉我们
02:24
that any object can become a black hole.
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任何物体都可以变成黑洞。
02:28
That means you, your neighbor, your cellphone,
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也就是说你， 你的邻居，还有你的手机，
02:31
the auditorium can become a black hole
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甚至这个听众席，都可能变成黑洞，
02:33
if you can figure out how to compress it down
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只要你能发现把物体压缩到
02:36
to the size of the Schwarzschild radius.
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施瓦西半径的大小。
02:38
At that point, what's going to happen?
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如果可以的话，很发生什么呢？
02:41
At that point gravity wins.
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此时，引力战胜了一切。
02:43
Gravity wins over all other known forces.
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引力战胜了我们所知的其他所有的力量。
02:45
And the object is forced to continue to collapse
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而物体本身也必须继续压缩
02:48
to an infinitely small object.
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直至变得无限小。
02:50
And then it's a black hole.
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这时黑洞就形成了。
02:52
So, if I were to compress the Earth down to the size of a sugar cube,
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所以如果我把地球压缩到方糖般大小
02:57
it would become a black hole,
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它就变成黑洞了，
02:59
because the size of a sugar cube is its Schwarzschild radius.
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因为方糖的大小就是地球的施瓦西半径的大小。
03:03
Now, the key here is to figure out what that Schwarzschild radius is.
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现在，关键就是要解决施瓦西半径到底是多大了。
03:06
And it turns out that it's actually pretty simple to figure out.
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其实在也很简单。
03:10
It depends only on the mass of the object.
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该半径取决于物体的质量。
03:12
Bigger objects have bigger Schwarzschild radii.
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物体大施瓦西半径就大
03:14
Smaller objects have smaller Schwarzschild radii.
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物体小相应地该半径也就小。
03:17
So, if I were to take the sun
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所以，如果我把太阳
03:19
and compress it down to the scale of the University of Oxford,
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压缩到和牛津大学一样大，
03:22
it would become a black hole.
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那么太阳就变成黑洞了。
03:25
So, now we know what a Schwarzschild radius is.
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现在我们知道施瓦西半径是什么了。
03:28
And it's actually quite a useful concept,
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了解这个很重要，
03:30
because it tells us not only
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它不仅告诉我们
03:32
when a black hole will form,
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何时形成黑洞，
03:34
but it also gives us the key elements for the proof of a black hole.
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同时也告诉我们找寻黑洞存在依据的关键
03:37
I only need two things.
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我只要知道两件事。
03:39
I need to understand the mass of the object
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我需要知道物体的质量，
03:41
I'm claiming is a black hole,
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我要把它变为黑洞，
03:43
and what its Schwarzschild radius is.
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还有它的施瓦西半径。
03:45
And since the mass determines the Schwarzschild radius,
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因为物体的质量决定了它的施瓦西半径，
03:47
there is actually only one thing I really need to know.
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所以实际上我只需要一件事。
03:49
So, my job in convincing you
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所以，我要你们相信
03:51
that there is a black hole
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黑洞的存在
03:53
is to show that there is some object
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就只要提供一个
03:55
that's confined to within its Schwarzschild radius.
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被压缩到施瓦西半径的物体就可以了。
03:58
And your job today is to be skeptical.
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而你们就今天就先保持自己的怀疑态度吧。
04:01
Okay, so, I'm going to talk about no ordinary black hole;
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好，接下来我要讲的绝不是普通的黑洞；
04:05
I'm going to talk about supermassive black holes.
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我将要介绍的是超质量的黑洞
04:08
So, I wanted to say a few words about what an ordinary black hole is,
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在此，我先说说什么是普通的黑洞，
04:10
as if there could be such a thing as an ordinary black hole.
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我们先假定存在这样的黑洞。
04:13
An ordinary black hole is thought to be the end state
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普通黑洞被认为是
04:16
of a really massive star's life.
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大恒星生命的终了状态。
04:18
So, if a star starts its life off
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因此，当一个恒星消亡
04:20
with much more mass than the mass of the Sun,
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而这个恒星的质量又远大于太阳，
04:22
it's going to end its life by exploding
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它将以爆炸结束生命
04:25
and leaving behind these beautiful supernova remnants that we see here.
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并留下我们见的那些漂亮的超新星残骸
04:28
And inside that supernova remnant
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在这些残骸之中
04:30
is going to be a little black hole
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就会有个小黑洞
04:32
that has a mass roughly three times the mass of the Sun.
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它的质量大约是太阳质量的三倍。
04:35
On an astronomical scale
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从天文学来看
04:37
that's a very small black hole.
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这个黑洞算是小的了。
04:39
Now, what I want to talk about are the supermassive black holes.
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下面我要讲的是特大黑洞了。
04:42
And the supermassive black holes are thought to reside at the center of galaxies.
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据说这些黑洞存在于星系的中心位置。
04:46
And this beautiful picture taken with the Hubble Space Telescope
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这张图片是哈勃望远镜拍下的，
04:49
shows you that galaxies come in all shapes and sizes.
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我们可以看到各种形状大小的星系。
04:52
There are big ones. There are little ones.
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有大的，也有小的。
04:54
Almost every object in that picture there is a galaxy.
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这里面几乎每个可见物体都是星系。
04:57
And there is a very nice spiral up in the upper left.
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看在左上角有个螺旋形
05:00
And there are a hundred billion stars in that galaxy,
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在那个星系里有一千亿的星星，
05:04
just to give you a sense of scale.
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让大家有个大小的意识。
05:06
And all the light that we see from a typical galaxy,
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在某个星系我们见的光，
05:08
which is the kind of galaxies that we're seeing here,
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就是我们现在看的这些星系，
05:10
comes from the light from the stars.
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是来自恒星的光。
05:12
So, we see the galaxy because of the star light.
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我们之所以能看见星系全是靠这些星星的光。
05:14
Now, there are a few relatively exotic galaxies.
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在这其中有不少相对来说奇怪的星系。
05:18
I like to call these the prima donna of the galaxy world,
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我习惯称它们为歌剧女王，
05:21
because they are kind of show offs.
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因为它们太能显摆了。
05:23
And we call them active galactic nuclei.
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我们叫它们活跃星系核子。
05:25
And we call them that because their nucleus,
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因为它们的核子活跃异常，
05:27
or their center, are very active.
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还有中心位置处。
05:30
So, at the center there, that's actually where
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所以在中间那块
05:32
most of the starlight comes out from.
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大部分星光都是从那发出的
05:34
And yet, what we actually see is light
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但是我们看见的只能说是光
05:36
that can't be explained by the starlight.
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不能说是星光。
05:39
It's way more energetic.
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因为这比星光更活跃。
05:41
In fact, in a few examples it's like the ones that we're seeing here.
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下面例子中跟我们现在看的这些有些相似。
05:43
There are also jets emanating out from the center.
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这些都是从中间发出来的。
05:46
Again, a source of energy that's very difficult to explain
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如果大家把星系认为是由星星组成的，
05:50
if you just think that galaxies are composed of stars.
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那这股能量就很难解释了。
05:52
So, what people have thought is that perhaps
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人们原来想
05:54
there are supermassive black holes
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或许是有特大的黑洞
05:57
which matter is falling on to.
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物质才被吸引过去的。
06:00
So, you can't see the black hole itself,
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我们看不见黑洞本身
06:02
but you can convert the gravitational energy of the black hole
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但是我们却可以把它的这种引力
06:05
into the light we see.
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转换为我们所见的光来思考
06:07
So, there is the thought that maybe supermassive black holes
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所以有这么一种想法就是特大黑洞或许
06:09
exist at the center of galaxies.
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存在于星系的中心处。
06:11
But it's a kind of indirect argument.
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但这仅是提供了一种间接论据
06:13
Nonetheless, it's given rise to the notion
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但是，这却让我们有了这样一种想法
06:15
that maybe it's not just these prima donnas
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或许不仅是这些歌剧女王
06:18
that have these supermassive black holes,
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有特大黑洞
06:20
but rather all galaxies might harbor these
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可能所有的星系
06:23
supermassive black holes at their centers.
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在中心位置处都有特大黑洞
06:25
And if that's the case -- and this is an example of a normal galaxy;
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假如这样的话--这就是个普通的星系；
06:28
what we see is the star light.
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我们看见的是星光
06:30
And if there is a supermassive black hole,
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假设存在这样的特大黑洞
06:32
what we need to assume is that it's a black hole on a diet.
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那么这个黑洞肯定是在节食
06:35
Because that is the way to suppress the energetic phenomena that we see
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因为这才能解释为什么在其它活跃星系核子的那股能量
06:38
in active galactic nuclei.
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在这却被压制住了。
06:41
If we're going to look for these stealth black holes
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如果我们想要在星系中心找寻
06:44
at the center of galaxies,
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这些隐藏的黑洞
06:46
the best place to look is in our own galaxy, our Milky Way.
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那么最好的地方就是在我们银河系寻找了。
06:50
And this is a wide field picture
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这张图片
06:52
taken of the center of the Milky Way.
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是银河系中心的大范围图片
06:55
And what we see is a line of stars.
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我们可以看到星星排成的列队
06:58
And that is because we live in a galaxy which has
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因为我们这个星系
07:00
a flattened, disk-like structure.
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结构像扁平的磁盘形状
07:02
And we live in the middle of it, so when we look towards the center,
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我们处在银河系的中心，所以如果我们看它的中心
07:04
we see this plane which defines the plane of the galaxy,
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我们把这个平面看成是银河的平面
07:06
or line that defines the plane of the galaxy.
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或者把这条线看成是银河平面
07:10
Now, the advantage of studying our own galaxy
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研究我们自己星系的好处呢
07:13
is it's simply the closest example of the center of a galaxy
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就是这是我们能找的星系中心最近的例子了
07:16
that we're ever going to have, because the next closest galaxy
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因为离我们再近点的星系
07:18
is 100 times further away.
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是我们离银河系中心100倍的距离之外了
07:21
So, we can see far more detail in our galaxy
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因而在我们这个星系我们可以把细节看的更清楚
07:23
than anyplace else.
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在其它地方就不行了
07:25
And as you'll see in a moment, the ability to see detail
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一会大家就知道了，能够观察到细节
07:27
is key to this experiment.
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是实验的关键
07:30
So, how do astronomers prove that there is a lot of mass
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那么天文学家怎样证明
07:33
inside a small volume?
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体积小质量大的物质呢
07:35
Which is the job that I have to show you today.
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今天我得给大家展示一下了
07:38
And the tool that we use is to watch the way
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我们要用的工具就是观察
07:40
stars orbit the black hole.
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这些星星是怎样绕黑洞运行的
07:43
Stars will orbit the black hole
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星星绕黑洞的运行轨迹
07:45
in the very same way that planets orbit the sun.
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跟行星绕太阳的轨迹差不多
07:48
It's the gravitational pull
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是引力
07:50
that makes these things orbit.
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使得物体按轨道运行的
07:52
If there were no massive objects these things would go flying off,
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如果是没有中间的大物体这些物体肯定就飞脱出去了
07:55
or at least go at a much slower rate
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至少是运行速度更慢
07:57
because all that determines how they go around
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因为决定它们运行轨迹的是
08:00
is how much mass is inside its orbit.
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轨道内含的质量大小
08:02
So, this is great, because remember my job is to show
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这下好了，记得吧我的任务就是说明
08:04
there is a lot of mass inside a small volume.
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体积小质量大的情况吧
08:06
So, if I know how fast it goes around, I know the mass.
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如果我知道物体的运行速度，我就可以知道它的质量了
08:09
And if I know the scale of the orbit I know the radius.
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还有如果我知道轨道大小就等于知道了轨道半径
08:12
So, I want to see the stars
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现在我想看看那些
08:14
that are as close to the center of the galaxy as possible.
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离星系中心越近越好的星星
08:16
Because I want to show there is a mass inside as small a region as possible.
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因为我想在尽小的区域内演示大质量
08:20
So, this means that I want to see a lot of detail.
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也就是说我想尽可能地看清楚些
08:23
And that's the reason that for this experiment we've used
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这就是为什么这次实验我们要用
08:25
the world's largest telescope.
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世界上最大的望远镜了
08:27
This is the Keck observatory. It hosts two telescopes
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这是凯克实验室，里面有两台望远镜
08:30
with a mirror 10 meters, which is roughly
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镜片有10米，这大约相当于
08:32
the diameter of a tennis court.
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一个网球场的宽了
08:34
Now, this is wonderful,
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这下好极了
08:36
because the campaign promise
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因为我们说过
08:38
of large telescopes is that is that the bigger the telescope,
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望远镜越大
08:41
the smaller the detail that we can see.
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我们就越能看到细节
08:45
But it turns out these telescopes, or any telescope on the ground
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但结果是这些望远镜，或是说所有的望远镜
08:48
has had a little bit of a challenge living up to this campaign promise.
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要达到我们的要求还是要战胜一点小困难
08:52
And that is because of the atmosphere.
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这就是我们的大气层了
08:54
Atmosphere is great for us; it allows us
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大气对我们是有好处的；它使得我们
08:56
to survive here on Earth.
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可以在地球上生存
08:58
But it's relatively challenging for astronomers
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这对天文学家们要想
09:01
who want to look through the atmosphere to astronomical sources.
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透过大气层看到观察物是有些挑战性的
09:05
So, to give you a sense of what this is like,
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说的更形象一点
09:07
it's actually like looking at a pebble
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这就像看水底的
09:09
at the bottom of a stream.
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小鹅卵石
09:11
Looking at the pebble on the bottom of the stream,
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我们要看河底的鹅卵石
09:13
the stream is continuously moving and turbulent,
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可是水流还是在不停地流动翻滚
09:16
and that makes it very difficult to see the pebble on the bottom of the stream.
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这要看清水底的鹅卵石就不容易了
09:20
Very much in the same way, it's very difficult
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同样情况下
09:22
to see astronomical sources, because of the
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我们要看清观测物
09:24
atmosphere that's continuously moving by.
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可是大气却在不停地动着，这就有难度了
09:26
So, I've spent a lot of my career working on ways
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所以我的大部分工作时间都用在了
09:29
to correct for the atmosphere, to give us a cleaner view.
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改造大气层以便可以清晰观察上。
09:32
And that buys us about a factor of 20.
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这就很难了
09:35
And I think all of you can agree that if you can
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我想大家都会相信
09:37
figure out how to improve life by a factor of 20,
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如果我们可以用®©来改善生活的话
09:40
you've probably improved your lifestyle by a lot,
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估计我们早想出很多其它的方法了
09:42
say your salary, you'd notice, or your kids, you'd notice.
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比如您的薪水，或是孩子
09:47
And this animation here shows you one example of
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这个动画实际上是我们
09:49
the techniques that we use, called adaptive optics.
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所用的一种技术，叫做自适应光学
09:52
You're seeing an animation that goes between
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从这个动画中我们可以看出
09:54
an example of what you would see if you don't use this technique --
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如果不用这种技术我们能看到的
09:57
in other words, just a picture that shows the stars --
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我们能看到的就是一张有星星的图片
10:00
and the box is centered on the center of the galaxy,
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图中的聚焦是星系的中心
10:02
where we think the black hole is.
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我们认为黑洞就在这里
10:04
So, without this technology you can't see the stars.
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不用这种技术我们就看不见星星
10:07
With this technology all of a sudden you can see it.
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用了呢我们就可以看见了
10:09
This technology works by introducing a mirror
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技术本身是把一面镜子
10:11
into the telescope optics system
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嵌入望远镜的光学系统
10:13
that's continuously changing to counteract what the atmosphere is doing to you.
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这样镜子的变化就可以把大气的变化抵消掉了。
10:18
So, it's kind of like very fancy eyeglasses for your telescope.
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这就像是给望远镜装上了魔幻镜片
10:22
Now, in the next few slides I'm just going to focus on
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下面几张幻灯片我主要讲
10:24
that little square there.
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这个小方块
10:26
So, we're only going to look at the stars inside that small square,
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我们就只看这个小方块里的星
10:28
although we've looked at all of them.
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虽然我们早就全看见了
10:30
So, I want to see how these things have moved.
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我想看看这些东西是怎么动的
10:32
And over the course of this experiment, these stars
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实验期间这些星星
10:34
have moved a tremendous amount.
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移动了好大的距离
10:36
So, we've been doing this experiment for 15 years,
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这个实验我们做了15年
10:38
and we see the stars go all the way around.
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星星一直都在动
10:40
Now, most astronomers have a favorite star,
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大部分天文学家都有自己最喜欢的星
10:43
and mine today is a star that's labeled up there, SO-2.
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我今天要讲的星在那，标为SO-2的那个
10:47
Absolutely my favorite star in the world.
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这是我的最爱
10:49
And that's because it goes around in only 15 years.
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这颗星运行到这才15年
10:52
And to give you a sense of how short that is,
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为了说明这是多短的时间我给大家提供一个数据
10:54
the sun takes 200 million years to go around the center of the galaxy.
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太阳要运行到银河系的中央大约要20000万年的时间
10:59
Stars that we knew about before, that were as close to the center of the galaxy
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之前我们看的那些星，就是离中心最近的
11:02
as possible, take 500 years.
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也要用500年
11:04
And this one, this one goes around in a human lifetime.
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这颗只要人的一生的时间就可以了
11:08
That's kind of profound, in a way.
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这很重要
11:10
But it's the key to this experiment. The orbit tells me
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这是实验的关键。轨道可以告诉我们
11:12
how much mass is inside a very small radius.
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小半径内到底藏了多大的质量
11:16
So, next we see a picture here that shows you
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从这张图片中我们可以看出
11:19
before this experiment the size to which we could
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我们可以把星系中心质量
11:21
confine the mass of the center of the galaxy.
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限制到多大的范围内
11:24
What we knew before is that there was four million
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之前我们认为在这个圆圈内
11:26
times the mass of the sun inside that circle.
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有太阳400万倍的质量
11:29
And as you can see, there was a lot of other stuff inside that circle.
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这个圈内还存在很多其它的物质
11:31
You can see a lot of stars.
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有很多星星
11:33
So, there was actually lots of alternatives
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这样看来似乎
11:35
to the idea that there was a supermassive black hole at the center of the galaxy,
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在星系中心有特大黑洞的猜想外还可以有不少其它的猜测
11:38
because you could put a lot of stuff in there.
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这可以填充的东西不少
11:40
But with this experiment, we've confined
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但是这次实验中
11:42
that same mass to a much smaller volume
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我们已把同质量的物质压缩到了一个相对较小的体积
11:45
that's 10,000 times smaller.
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是原来的一万分之一
11:49
And because of that, we've been able to show
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正因为这样，我们才能够
11:51
that there is a supermassive black hole there.
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证明特大黑洞的存在
11:53
To give you a sense of how small that size is,
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这有多小呢
11:55
that's the size of our solar system.
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这就跟我们的太阳系一般大小
11:57
So, we're cramming four million times the mass of the sun
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所以现在我们是把400万倍于太阳质量的物体
12:01
into that small volume.
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缩小到这么大小
12:03
Now, truth in advertising. Right?
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广告中的真相？
12:06
I have told you my job is to get it down to the Schwarzchild radius.
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之前说过我今天就是要把它缩到施瓦西半径
12:09
And the truth is, I'm not quite there.
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但实际上是我目前还没有办到
12:11
But we actually have no alternative today
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但是今天我们必须要
12:13
to explaining this concentration of mass.
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解释这个质量集合点
12:16
And, in fact, it's the best evidence we have to date
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实际上这是目前为止我们
12:19
for not only existence of a supermassive black hole
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找寻星系中心黑洞存在的最好的依据了
12:21
at the center of our own galaxy, but any in our universe.
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甚至是找寻宇宙中任何一个
12:24
So, what next? I actually think
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我在想下面讲什么呢
12:27
this is about as good as we're going to do with today's technology,
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这跟我们今天讨论的技术一样
12:29
so let's move on with the problem.
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下面我们继续讲这个问题
12:31
So, what I want to tell you, very briefly,
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简短地给大家介绍
12:33
is a few examples
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几个例子
12:35
of the excitement of what we can do today
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这会让人很兴奋的
12:37
at the center of the galaxy, now that we know that there is,
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在星系的中心，有
12:39
or at least we believe,
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至少我们这么认为
12:41
that there is a supermassive black hole there.
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一个特大的黑洞
12:43
And the fun phase of this experiment
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这个实验有趣的是
12:45
is, while we've tested some of our ideas
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我们已经试验过几个
12:48
about the consequences of a supermassive black hole
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有关黑洞推论的想法
12:50
being at the center of our galaxy,
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当然了是在我们星系的中心处的黑洞
12:52
almost every single one
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几乎每一个
12:54
has been inconsistent with what we actually see.
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跟我们见的是不一样的
12:56
And that's the fun.
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这就有意思了
12:58
So, let me give you the two examples.
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再给大家举两个例子
13:00
You can ask, "What do you expect
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大家可能会问，
13:02
for the old stars, stars that have been around the center of the galaxy
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“那些古老的星星呢，就是那些长久以来在星系中心的星”
13:04
for a long time, they've had plenty of time to interact with the black hole."
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它们跟黑洞可有足够的时间接触
13:08
What you expect there is that old stars
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你想的是
13:10
should be very clustered around the black hole.
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黑洞周围该有成群的星星绕在那
13:12
You should see a lot of old stars next to that black hole.
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实际上那些古老的星星是在黑洞近处的
13:16
Likewise, for the young stars, or in contrast, the young stars,
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同样那些年轻的星，或者说，相反，那些年轻的星
13:20
they just should not be there.
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就不该在那了
13:22
A black hole does not make a kind neighbor to a stellar nursery.
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黑洞对那些恒星群可不怎么友好
13:26
To get a star to form, you need a big ball of gas and dust to collapse.
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一个气体和尘埃的大球崩溃后星星就形成了
13:30
And it's a very fragile entity.
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这个实体可是很脆弱的
13:32
And what does the big black hole do?
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那么黑洞是干什么的呢
13:34
It strips that gas cloud apart.
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它能够把那个气体层剥去
13:36
It pulls much stronger on one side than the other
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并且黑洞在一侧的用力比另一侧大很多
13:38
and the cloud is stripped apart.
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这样这层云就被剥去了
13:40
In fact, we anticipated that star formation shouldn't proceed in that environment.
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实际上我们原来不认为星星能够在那中环境中形成
13:43
So, you shouldn't see young stars.
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所以，你不会看见年轻的星星
13:45
So, what do we see?
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看看这个
13:47
Using observations that are not the ones I've shown you today,
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这些资料不是我之前给大家讲的
13:49
we can actually figure out which ones are old and which ones are young.
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其实年老跟年轻的星星我们是可以分开的
13:52
The old ones are red.
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年老的是红色的
13:54
The young ones are blue. And the yellow ones, we don't know yet.
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年轻的是蓝色的，那些黄色的呢，我们也不知道
13:57
So, you can already see the surprise.
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奇怪的事发生了
13:59
There is a dearth of old stars.
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年老的星星并不多
14:01
There is an abundance of young stars, so it's the exact opposite of the prediction.
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有很多年轻的星星，这跟我们的预测可正好相反
14:05
So, this is the fun part.
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有意思
14:07
And in fact, today, this is what we're trying to figure out,
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这就是我们今天要解决的
14:09
this mystery of how do you get --
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神秘
14:11
how do you resolve this contradiction.
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怎样来解决这个矛盾
14:13
So, in fact, my graduate students
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我的研究生
14:15
are, at this very moment, today, at the telescope,
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就在此刻
14:19
in Hawaii, making observations to get us
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正在夏威夷的望远镜旁记录数据
14:22
hopefully to the next stage,
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希望我们可以我们可以做进一步的研究
14:24
where we can address this question
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那时我们就可以就这个问题
14:26
of why are there so many young stars,
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为什么有这么多的年轻的星
14:28
and so few old stars.
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这么少的年老的星讲讲了
14:30
To make further progress we really need to look at the orbits
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如果我们要有进展的话，我们需要看
14:32
of stars that are much further away.
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更远处星的轨道
14:34
To do that we'll probably need much more
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要是那样的话，我们就需要
14:36
sophisticated technology than we have today.
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比今天更精密的技术了
14:38
Because, in truth, while I said we're correcting
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刚才我说我们在
14:40
for the Earth's atmosphere, we actually only
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矫正地球的大气层，但实际上
14:42
correct for half the errors that are introduced.
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我们仅仅矫正了一半的不利因素
14:44
We do this by shooting a laser up into the atmosphere,
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我们打一束激光到大气层
14:47
and what we think we can do is if we
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我们想如果我们
14:50
shine a few more that we can correct the rest.
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多打几束就可以把余下的也都矫正过来
14:52
So this is what we hope to do in the next few years.
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接下来几年中希望我们可以做到
14:54
And on a much longer time scale,
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更长远一点呢
14:56
what we hope to do is build even larger telescopes,
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我们希望建造大点的望远镜
14:59
because, remember, bigger is better in astronomy.
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还记得吗在天文学中越大越好
15:02
So, we want to build a 30 meter telescope.
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所以我们想建一个30米的望远镜
15:04
And with this telescope we should be able to see
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有了这个望远镜我们就可以
15:06
stars that are even closer to the center of the galaxy.
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离星系中心更近的星了
15:09
And we hope to be able to test some of
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我们还希望可以验证
15:11
Einstein's theories of general relativity,
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爱因斯坦广义相对论的某些理论
15:14
some ideas in cosmology about how galaxies form.
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宇宙论中有关星系的形成方面的一些想法
15:17
So, we think the future of this experiment
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所以未来的实验
15:19
is quite exciting.
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还是很有意思的
15:22
So, in conclusion, I'm going to show you an animation
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最后，给大家看一个动画
15:24
that basically shows you how these
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主要是想给大家看
15:26
orbits have been moving, in three dimensions.
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这些轨道在三维中是怎样变化的
15:29
And I hope, if nothing else,
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我希望
15:31
I've convinced you that, one, we do in fact
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大家如果不相信别的，那么起码今天
15:33
have a supermassive black hole at the center of the galaxy.
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你该相信在星系的中心有特大黑洞了
15:36
And this means that these things do exist in our universe,
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也就是说宇宙中确实存在这些东西
15:39
and we have to contend with this, we have to explain
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这些我们必须接受，我们必须解释
15:41
how you can get these objects in our physical world.
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怎样在我们的现实世界中得到这样的东西
15:44
Second, we've been able to look at that interaction
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其次，我们看了
15:47
of how supermassive black holes interact,
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这些特大黑洞之间的相互作用
15:50
and understand, maybe, the role in which they play
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或许我们就明白了这些黑洞
15:54
in shaping what galaxies are, and how they work.
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在星系的形成中扮演什么样的角色，以及它们是怎样起作用的
15:57
And last but not least,
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最后
15:59
none of this would have happened
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所有这一切
16:01
without the advent of the tremendous progress
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如果没有科技前沿的巨大进步
16:04
that's been made on the technology front.
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就不会取得
16:06
And we think that this is a field that is moving incredibly fast,
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我们相信这个领域正以飞快的速度前进
16:10
and holds a lot in store for the future.
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并且还有很大的发展空间
16:13
Thanks very much.
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非常感谢
16:15
(Applause)
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掌声
ABOUT THE SPEAKER
Andrea Ghez - AstronomerAndrea Ghez is a stargazing detective, tracking the visible and invisible forces lurking in the vastness of interstellar space.
Why you should listen
Seeing the unseen (from 26,000 light-years away) is a specialty of UCLA astronomer Andrea Ghez. From the highest and coldest mountaintop of Hawaii, home of the Keck Observatory telescopes, using bleeding-edge deep-space-scrying technology, Ghez handily confirmed 30 years of suspicions of what lies at the heart of the Milky Way galaxy -- a supermassive black hole, which sends its satellite stars spinning in orbits approaching the speed of light.
Ghez received a MacArthur "genius grant" in 2008 for her work in surmounting the limitations of earthbound telescopes. Early in her career, she developed a technique known as speckle imaging, which combined many short exposures from a telescope into one much-crisper image. Lately she's been using adaptive optics to further sharpen our view from here -- and compile evidence of young stars at the center of the universe.
Andrea Ghez | Speaker | TED.com