PatriciaBurchat_解释暗物质【中英文对照】

1.As a particle physicist, I study the elementary particles and how they interact on the most fundamental level.
作为一名粒子物理学家，我研究基本粒子 以及它们如何在微观上如何相互作用
2.For most of my research career I’ve been using accelerators, such as the electron accelerator at Stanford University, just up the road,
对于我大部分的研究，我一直在使用加速器， 例如在斯坦福大学路边的电子加速器
3.to study things on the smallest scale.
去在微观上研究物质。
4.But more recently, I’ve been turning my attention to the universe on the largest scale.
但是最近，我的注意力转向了 宏观上整个宇宙。
5.Because, as I’ll explain to you, the questions on the smallest and the largest scale are actually very connected.
因为，正如我将要对你们解释的， 宏观和微观上的问题其实是非常相关的。
6.So I’m going to tell you about our 21st-century view of the universe, what it’s made of and what the big questions in the physical sciences are —
所以我将要告诉你们关于我们21世纪的宇宙观， 它是由什么构成的，以及什么是物理学中的一些大问题—
7.at least some of the big questions.
至少是它们中的一些大问题。
8.So recently, we have realized that the ordinary matter in the universe — and by ordinary matter I mean you, OK, me, the planets, the stars, the galaxies —
最近，我们意识到 宇宙中的普通物质— 我指的普通物质，我的意思是你，我 行星，横星，银河系—
9.the ordinary matter makes up only a few percent of the content of the universe.
普通物质仅仅占据 宇宙组成的一小部分。
10.Almost a quarter, or approximately a quarter of the matter in the universe, is stuff that’s invisible.
近乎四分之一，或者大约四分之一 的宇宙组成是一些不可见的东西。
11.By invisible I mean it doesn’t absorb in the electromagnetic spectrum.
不可见，我指的是它不吸收地磁波谱。
12.It doesn’t emit in the electromagnetic spectrum. It doesn’t reflect.
在光谱中不放射电磁波。它不反射电磁波。
13.It doesn’t interact with the electromagnetic spectrum, which is what we use to detect things.
它在电磁波谱照射下不发生反应， 而这却是我们如何用来检测物质的方法。
14.It doesn’t interact at all. So how do we know it’s there?
它根本不反应。所以我们如何知道它们在那？
15.We know it’s there by its gravitational effects.
我的得知它们存在通过引力效应。
16.In fact, this dark matter dominates the gravitational effects in the universe on a large scale, and I’ll be telling you about the evidence for that.
实际上，这种暗物质 宏观上统治宇宙中的引力效应， 我将会告诉你们它的证据。
17.What about the rest of the pie?
派的其它部分是什么呢？
18.The rest of the pie is a very mysterious substance called dark energy.
这个派的其它部分是一种十分神秘的物质，叫做暗能量。
19.More about that later, OK.
一会再讨论它。
20.So for now, let’s turn to the evidence for dark matter.
所以现在，我们来谈谈暗物质存在的证据。
21.In these galaxies, especially in a spiral galaxy like this, most of the mass of the stars is concentrated in the middle of the galaxy.
在这些星系中，尤其是在一个像这样的螺旋星系中， 大部分的质量集中在星系的中央。
22.This huge mass of all these stars keeps stars in circular orbits in the galaxy.
这些恒星巨大的质量使得这些星星在星系中沿圆周运动轨道运动。
23.So we have these stars going around in circles like this.
所以我们看到这些恒星沿圆圈这样运动。
24.As you can imagine, even if you know physics — this should be intuitive, OK — that stars that are closer to the mass in the middle will be rotating at a higher speed
如你所想，即使你不知道物理—-这应该是很直观的， 这些靠近中心的恒星将会以更高的速度旋转，
25.than those that are further out here, OK.
相比于在外面的这些。
26.So what you would expect is that if you measured the orbital speed of the stars, that they should be slower on the edges than on the inside.
所以，你所期待的也许是如果你测量这些恒星运动的轨道速度， 它们（速度）应该是边缘的比里面的慢。
27.In other words, if we measured speed as a function of distance — this is the only time I’m going to show a graph, OK — we would expect that it goes down as the distance increases
换言之，如果我们测量速度作为距离的函数— 这是我唯一一次展示图表，好吗？ 我们会期待它（速度）会减小
28.from the center of the galaxy.
随着距离星系中央的路程增加。
29.When those measurements are made, instead what we find is that the speed is basically constant, as a function of distance.
当这些被测量， 反而，我们发现这个速度基本上是一个常数， 作为距离的函数。
30.If it’s constant, that means that the stars out here are feeling the gravitational effects of matter that we do not see.
如果它（速度）是一个常数，这意味着外面的恒星 正在感受到一些我们看不到物质所施加的引力效应。
31.In fact, this galaxy and every other galaxy appears to be embedded in a cloud of this invisible dark matter.
事实上，这个星系以及每一个其它的星系 似乎被内嵌在一团我们看不到的暗物质中。
32.And this cloud of matter is much more spherical than the galaxy themselves, and it extends over a much wider range than the galaxy.
这团物质比星系本身更加类似于球形， 而且它们（暗物质）比星系本身延伸至更广的范围。
33.So we see the galaxy and fixate on that, but it’s actually a cloud of dark matter that’s dominating the structure and the dynamics of this galaxy.
所以，我们注视着这个星系，但是它其实实在一团 决定它们结构与动态的暗物质中。
34.Galaxies themselves are not strewn randomly in space; they tend to cluster.
星系本身并不是任意地散布在空间中； 它们趋向于聚集在一起。
35.And this is an example of a very, actually, famous cluster: the Coma cluster.
这是一个实际上非常著名的星系团：后发座（Coma）星系团。
36.And there are thousands of galaxies in this cluster.
而且这个星系团中有数以千计的星系。
37.They’re the white, fuzzy, elliptical things here.
它们是这些白色的，模糊的，椭圆的东西。
38.So these galaxy clusters — we take a snapshot now, we take a snapshot in a decade — it’ll look identical.
所以，这些星系团——我们现在拍一张照， 十年后我们拍一张照——它们将会看起来一模一样。
39.But these galaxies are actually moving at extremely high speeds.
但是这些星系团其实在以极高的速度运动。
40.They’re moving around in this gravitational potential well of this cluster, OK.
它们其实在这个星系团的引力势阱中运动。
41.So all of these galaxies are moving.
所以，这些星系在运动。
42.We can measure the speeds of these galaxies, their orbital velocities, and figure out how much mass is in this cluster.
我们可以测量这些星系的速率，它们的轨道速度， 并算出星系团中有多少质量。
43.And again, what we find is that there is much more mass there than can be accounted for by the galaxies that we see.
并且再一次，我们发现的这里有更多的质量 相比于我们实际看到的星系所能证明的。
44.Or if we look in other parts of the electromagnetic spectrum, we see that there’s a lot of gas in this cluster, as well.
或者我们看其它部分的电磁波谱， 我们看到这里也有很多气体。
45.But that cannot account for the mass either.
但是那也不能解释这些质量。
46.In fact, there appears to be about ten times as much mass here in the form of this invisible or dark matter as there is in the ordinary matter, OK.
事实上，这里有大约10倍多的质量 以暗物质存在 相比于普通物质。
47.It would be nice if we could see this dark matter a little bit more directly.
如果我们能更直接地看到暗物质，那会更好
48.I’m just putting this big, blue blob on there, OK, to try to remind you that it’s there.
我只放一个大的蓝色的水泡在这里， 试图提醒你它们（暗物质）在这里。
49.Can we see it more visually? Yes, we can.
我们能更形象地看到它们嘛？是的，我们可以。
50.And so let me lead you through how we can do this.
那么让我帮助你们了解如何这样做。
51.So here’s an observer: it could be an eye; it could be a telescope.
那么这里是一个观察器： 它可以是一只眼睛；它可以是一个望远镜。
52.And suppose there’s a galaxy out here in the universe.
假设在宇宙中有一个星系。
53.How do we see that galaxy?
我们如何能看到那个星系？
54.A ray of light leaves the galaxy and travels through the universe for perhaps billions of years before it enters the telescope or your eye.
一束光离开星系并穿过宇宙 经过了也许几十亿年 在它进入望远镜或者你的眼睛之前。
55.Now, how do we deduce where the galaxy is?
现在，你如何猜测星系的位置？
56.Well, we deduce it by the direction that the ray is traveling as it enters our eye, right?
嗯，我们猜测它的位置根据光线传播 进入我们眼睛的方向？
57.We say, the ray of light came this way; the galaxy must be there, OK.
例如，这束光这样出来， 星系一定在那。
58.Now, suppose I put in the middle a cluster of galaxies — and don’t forget the dark matter, OK.
现在，假设我在屏幕中央放一个星系团— 别忘了还有暗物质，好吗？
59.Now, if we consider a different ray of light, one going off like this, we now need to take into account what Einstein predicted when he developed general relativity.
现在，如果我们考虑另外一束像这样离开的光线， 我们现在需要考虑 爱因斯坦当他发展广义相对论的时候，曾经预言过的（现象）。
60.And that was that the gravitational field, due to mass, will deflect not only the trajectory of particles, but will deflect light itself.
那就是由于有质量，引力场 不仅会使粒子的运动轨迹偏转， 而且会使光本身偏转。
61.So this light ray will not continue in a straight line, but would rather bend and could end up going into our eye.
所以这束光不会沿直线行进， 相反会弯曲然后最终进入我们的眼睛
62.Where will this observer see the galaxy?
这个观察器会在哪里看到星系呢？
63.You can respond. Up, right?
你们可以回答我。上面，对吗？
64.We extrapolate backwards and say the galaxy is up here.
我们倒推然后确定星系在这里。
65.Is there any other ray of light that could make into the observer’s eye from that galaxy?
这里还有其它的 可以进入观察者眼睛的光线嘛？
66.Yes, great. I see people going down like this.
是的，非常好。我看到人们做向下的姿势。
67.So a ray of light could go down, be bent up into the observer’s eye, and the observer sees a ray of light here.
一束光也可以往下走，然后弯曲 进入观察者的眼睛， 这个观察着便会在这里看到一束光。
68.Now, take into account the fact that we live in a three-dimensional universe, OK, a three-dimensional space.
现在，考虑我们生活在 三维宇宙的事实 一个三维空间。
69.Are there any other rays of light that could make it into the eye?
还有其它光线可以进入我们的眼睛嘛？
70.Yes! The rays would lie on a — I’d like to see — yeah, on a cone.
是的，光线可以排列在一个—我希望看到—对了，一个圆锥形
71.So there’s a whole ray of light — rays of light on a cone — that will all be bent by that cluster and make it into the observer’s eye.
所以，许多束光会在一个圆锥上— 它们都被弯曲过 然后进入观察者的眼睛。
72.If there is a cone of light coming into my eye, what do I see?
如果有锥形的光进入我的眼睛，我看到了什么？
73.A circle, a ring. It’s called an Einstein ring — Einstein predicted that, OK.
一个圆圈，一个环形。它被称作一个爱因斯坦环—爱因斯坦预言了它
74.Now, it will only be a perfect ring if the source, the deflector, and the eyeball, in this case, are all in a perfectly straight line.
那么，它仅仅会是一个完美的环形如果它的源，这个偏导物质 以及我们的眼球，在这个情况下，恰好在一条直线上。
75.If they’re slightly skewed, we’ll see a different image.
如果它们被略微偏转，我们将会看到一个不同的图像
76.Now, you can do an experiment tonight over the reception, OK, to figure out what that image will look like.
你们今晚在招待会后可以做一个试验， 去看到这个图像会是什么样子。
77.Because it turns out that there is a kind of lens that we can devise, that has the right shape to produce this kind of effect.
因为我们可以设计一种透镜， 它（透镜）有产生这种现象的合适的形状。
78.We call this gravitational lensing.
我们称它为引力透镜。
79.And so, this is your instrument, OK.
所以，这是你们的仪器
80.(Laughter).
（笑声）
81.But ignore the top part.
但是忽略上部。
82.It’s the base that I want you to concentrate, OK.
我希望你们关注它的底座。
83.So actually, at home, whenever we break a wineglass, I save the bottom, take it over to the machine shop.
所以实际上，在家里，不管何时我们打碎一个玻璃酒杯， 我保留它的底部，把它送去机械修理店。
84.We shave it off, and I have a little gravitational lens, OK.
我们把它剃掉，然后我就有了一个引力透镜。
85.So it’s got the right shape to produce the lensing.
所以，它有合适产生透镜效果的形状。
86.And so the next thing you need to do in your experiment, is grab a napkin. I grabbed a piece of graph paper; I’m a physicist. (Laughter)
所以，你在实验中需要做的下一件事情， 就是找来一张餐巾纸。我找来了一张坐标纸；我是一个物理学家。（笑声）
87.So, a napkin. Draw a little model galaxy in the middle.
那么，一张餐巾纸。在中间画一个小小的星系模型。
88.And now put the lens over the galaxy, and what you’ll find is that you’ll see a ring, an Einstein ring.
然后现在把透镜放到星系上， 你将看到的是，一个爱因斯坦环。
89.Now, move the base off to the side, and the ring will split up into arcs, OK.
现在，把底座移到另一边， 然后，这个圆环会分裂成一些弧形。
90.And you can put it on top of any image.
你可以把它放到任何图像上。
91.On the graph paper you can see how all the lines on the graph paper have been distorted.
在坐标纸上你可以看到 这些线是如何被扭曲的。
92.And again, this is a, a kind of an accurate model of what happens with the gravitational lensing.
再一次说明，这是一种非常精确的模型 去解释引力透镜产生的现象。
93.OK, so the question is: do we see this in the sky?
那么，问题是：我们在天空中看到这个吗？
94.Do we see arcs in the sky when we look at, say, a cluster of galaxies?
当我们看一个星系团的时候，我们能看到弧形吗？
95.And the answer is: yes.
答案是:是的。
96.And so, here’s an image from the Hubble space telescope.
这是来自哈勃望远镜的图像。
97.Many of the images you are seeing are earlier from the Hubble space telescope.
你看到的许多图像 来自早期的哈勃望远镜。
98.Well, first of all, for the golden shape galaxies — those are the galaxies in the cluster.
嗯，首先，关于这些金色的星系— 它们是在星系团中的一些星系。
99.They’re the ones that are embedded in that sea of dark matter that are causing the bending of the light to cause these optical illusions, or mirages, practically,
它们嵌在一团暗物质中 因而引起了光的弯曲 引起了这些视错觉，或者差不多，蜃景，
100.of the background galaxies.
来自后面的星系。
101.So the streaks that you see, all these streaks, are actually distorted images of galaxies that are much further away.
所以你看到条纹，所有这些条纹， 其实都是更远出的扭曲的星系的图像。
102.So what we can do, then, is based on how much distortion we see in those images, we can calculate how much mass there must be in this cluster.
那么我们能做的，就是根据扭曲程度的大小 来自这些图像，我们可以计算出 在这团星系中一定有多少质量。
103.And it’s an enormous amount of mass.
质量的总额是十分庞大的。
104.And also, you can tell by eye, by looking at this, that these arcs are not centered on individual galaxies; they are centered on some more spread out structure.
所以，你可以通过观察它（图像），辨别 这些弧线的中心不是某一个星系； 它们（弧线）以一个更加扩散的的结构为中心。
105.And that is the dark matter in which the cluster is embedded, OK.
这就是暗物质 星系嵌入其中。
106.So this is the closest you can get to kind of seeing at least the effects of the dark matter with your naked eye.
这是最接近于看到 至少通过肉眼看到暗物质的影响。
107.OK, so, a quick review then, to see that you’re following.
那么，一个非常快的回顾，以知道你们正在跟随。
108.So the evidence that we have that a quarter of the universe is dark matter — this gravitationally attracting stuff — is that galaxies, the speeds with which stars orbiting galaxies
我们有的证据 证明这?是暗物质— 这些以引力作用吸引的东西— （证据）是这些行星围绕星系运动的速率
109.is much too large; it must be embedded in dark matter.
（速率）过大；它（行星）一定嵌在暗物质中
110.The speed with which galaxies within clusters are orbiting is much too large; it must be embedded in dark matter.
星系在星系团中的圆周运动速度太大了； 它（星系）一定嵌在暗物质中
111.And we see these gravitational lensing effects, these distortions that say that, again, clusters are embedded in dark matter.
我们看到了这些引力透镜的效应。这些扭曲（的现象） 再次证明，星系团嵌在暗物质中。
112.OK. So now, let’s turn to dark energy.
好。现在我们转向暗能量。
113.So to understand the evidence for dark energy, we need to discuss something that Stephen Hawking referred to in the previous session.
所以为了了解暗能量的证据，我们需要讨论一些 史蒂芬霍金前一段谈到的现象。
114.And that is the fact that space itself is expanding.
那就是宇宙正在扩张的事实。
115.So if we imagine a section of our infinite universe, OK, and so I’ve put down four spiral galaxies, OK.
所以如果我们想象无限宇宙中一小部分， 然后我放4个漩涡星系，
116.And imagine that you put down a set of tape measures, so every line on here corresponds to a tape measure — horizontal or vertical — for measuring where things are.
假设你放一套卷尺， 这里的每一条线对以一个卷尺— 水平的或垂直的—用来测量东西的位置。
117.If you could do this, what you would find that with each passing day, each passing year, each passing billions of years, OK, the distance between galaxies is getting greater.
如果你可以这样做，你将发现的是 每过去一天，每过去一年， 每过去几十亿年 星系间的距离正在变得更大。
118.And it’s not because galaxies are moving away from each other through space; they’re not necessarily moving through space.
然而这并不是因为星系在运动 在空间中互相远离； 他们不一定在动。
119.They’re moving away from each other because space itself is getting bigger, OK.
他们正在远离对方 因为空间本身正在扩张。
120.That’s what the expansion of the universe or space means.
这是宇宙或者空间扩张的意思。