How We Could Solve the Dark Matter Mystery | Chanda Prescod-Weinstein | TED

翻译人员: Yip Yan Yeung 校对人员: Yanyan Hong

When we look at the night sky,

当我们注视夜空之时，

we see a vast cosmos

我们会看到广袤的宇宙，

filled with stars and galaxies and dust,

布满星星、星系和星尘，

a cosmos teeming with luminous phenomena.

一个闪烁着星光的宇宙。

So we've all heard some version of that famous Carl Sagan line,

我们都听说过卡尔·萨根 （Carl Sagan）的名言：

"We are made of star stuff."

“人类源自星尘。”

And it's true, we are.

没错，确实如此。

And that makes it easy to believe that what matters is what's visible --

这让我们轻易地断定 物质就是可见物——

us, the trees, the stars --

我们自己、树木、星星，

because it helps us feel connected to everything that we can see.

因为这样我们可以感受到与 肉眼可见的物体之间的联结。

Today, we know that everything visible in the universe

如今，我们已经知道 宇宙中的所有可见物

is composed from a basic set of building blocks

由一系列基本元素组成，

known as elementary particles.

它们被称为基本粒子 （elementary particle）。

We call this incredibly elegant picture

我们将这张精美的图片称为

the standard model of particle physics,

粒子物理标准模型 （Standard Model of Particle Physics），

and we understand it in great mathematical detail.

我们已经从数学角度 深入了解了它。

Comprehending the standard model is an enormous achievement.

理解这个标准模型 是一个伟大的成就。

But we are now certain that it describes very little of what's out there.

但是我们现在确信它描述的 只是宇宙的一小部分。

It turns out that most of the stuff which fills our universe

填满宇宙的大部分物质

is completely invisible to us.

对我们来说完全不可见。

In other words, visible matter,

换句话说，可见物质——

the kind that we and the stars are made from,

我们人类和恒星的来源，

the kind that radiates light,

辐射出光线的物质，

is not what's normal.

并不是物质的大多数。

And we, the luminous matter,

我们作为发光体，

we are the cosmic weirdos.

是宇宙的异类。

So how do we know?

我们是如何得知的呢？

Well, consider this invisible nonbinary person,

我们来看这位隐形的 非二元性别人士，

who's hiding in plain sight inside of their suit.

他（她）穿着西装，不为我们所见，

We can't exactly see a person,

我们无法“看见”这个人，

but we know that they're there, because the suit is filled out.

但是我们知道他（她）就在那里， 因为西装里有所存在。

So the presence of the invisible enby

所以这位非二元性别者的存在

is governing how the suit hangs in space-time.

决定了这件西装 在时空上的呈现状态。

So we can see a similar effect with visible matter.

我们可以将这个现象 沿用至可见物质上。

We can see that stars and galaxies are affected

我们可以看出恒星和星系

by the presence of something more,

被一些别的东西影响，

something completely invisible to us.

一些我们完全看不见的东西。

So we now know that the universe is more queer and fantastical

我们现在知道了，宇宙比我们

than it looks to the naked eye.

肉眼所见的更加光怪陆离。

(Cheers)

（欢呼）

(Laughter)

（笑声）

That's right.

没错。

(Laughter and applause)

（笑声与掌声）

So how did the universe get this way,

那么宇宙是怎么变成这样的呢？

and what exactly is inside?

宇宙到底包含了什么？

So I'm a theoretical physicist

我是一个理论物理学家，

with expertise in particle cosmology.

专攻粒子宇宙学。

And it's my job to use math

我们的工作是通过数学

to study the origin and evolution of space-time

研究时空和其中每一个物体的

and every single thing that's inside of it.

起源和演变。

I connect the very small -- elementary particles --

我将微小的基本粒子与

with the extremely large -- galaxies and galaxy clusters,

庞大的星系和星系团联系在一起，

and I'm a griot of the universe.

我是记载宇宙的史官。

I develop creative mathematical narratives

我写下充满创意的数学故事，

that may just be our cosmic origin story.

也就是我们的宇宙起源故事。

Now as a theoretical physicist, I really love doing math

作为一名理论物理学家， 我很喜欢做数学，

and coming up with different ideas

想出各种各样的想法，

that may describe our mostly invisible universe.

描述我们这个 大部分不可见的宇宙。

But it's important to be accountable to data too,

但是我也得对数据

the real stuff.

这样的干货负责。

So after mathematics,

除了数学，

my second favorite tool for addressing these large cosmological questions

我最喜欢用已知最大的实验室来解决

is the biggest laboratory we know,

这些庞大的宇宙问题，

the universe itself.

这个实验室就是宇宙本身。

Observatories with capabilities from visible light

天文台可以观测可见光、

to high-energy X-ray and gamma-ray photons

高能 X 射线、伽马射线光子，

are still some of the best ways to gain insight

这些仍是我们通过可见物质

into what's going on in space-time, with the invisible stuff.

了解时空情况的最佳途径。

So what you're looking at here is the Vera C. Rubin Observatory,

这是薇拉·鲁宾天文台 （Vera C. Rubin Observatory），

an exciting new facility

这台令人激动的全新设备

that's about to see its first light over the next two years.

会在两年内看见第一束光。

It's a leading example of a new generation of telescopes

这是新一代望远镜的出色例子，

that are going to change the way we see this mostly invisible universe.

它们会改变我们观测 大部分不可见宇宙的方式。

Now it's also the case that swarms of satellites

现在还有一大堆卫星

threaten images from ground-based facilities like this one.

会影响地面设备捕捉到的图像。

But the Vera C. Rubin Observatory can help us understand

但是薇拉·鲁宾天文台 帮助我们了解了

where the invisible stuff is and what it's doing,

不可见物质都在何处、 在做些什么，

which will help us determine what exactly it is.

有助于我们推断它到底是什么。

So when it comes to the cosmic accounting,

如果我们要对宇宙进行一番计算，

here is what we know so far.

以下是我们已知的信息。

We're in the midst of a great cosmic drama,

我们正处于一场宇宙剧变之中，

where space-time is curved and it’s expanding.

时空弯曲，正在膨胀。

And the history and future of that curvature and expansion

曲度和膨胀的历史和未来

is determined by what's inside,

由其中内含决定，

which is mostly not visible stuff like us --

大部分都不是 像我们这样的可见物，

that's only about five percent.

可见物只占大约 5%。

The majority of the energy-matter content in the universe

宇宙中大部分带有能量的物质

is something that we call dark energy.

是我们称为暗能量的东西。

So empty space seems to have an energy associated with it.

这些真空的区域 似乎有着一股能量，

And that's increasingly affecting how space-time expands.

显著影响了时空膨胀的进程。

After dark energy,

暗能量之外的

the second-largest ingredient is something that we call dark matter.

第二大成分被称为暗物质。

So here's the funky thing about dark matter.

暗物质有一个独特之处。

Unlike dark energy,

它与暗能量不同，

it gravitates exactly like visible matter.

它会和可见物质一样受到引力作用，

But it's completely unlike us in every other way.

但是其余无一与我们相似之处。

So you might be thinking,

你可能会想：

"OK, dark matter.

好吧，暗物质。

It clearly has a color associated with it."

肯定有颜色。”

It's dark, like my pants.

它就像我的裤子这样的深色。

Right?

对吧？

But the first thing you should know about dark matter

但是你需要了解 暗物质的第一件事就是

is that it doesn't have a color,

它没有颜色，

and at least at first approximation,

粗略地讲，

light seems to go right through it, so we can't see it.

光线会直接射穿它， 所以我们无法看见它。

It's invisible, maybe transparent, maybe clear.

它是不可见的， 也许是清晰透明的。

So if you put out your hands

如果你伸出手，

and think about the weight of having a clump of dark matter in your hands --

想象一下 手中有一大团暗物质的重量，

that's how it would feel,

就是这种感觉，

but your hands would look exactly the same.

但是你的手看上去没有任何变化。

Today, we believe

我们现在认为

that 80 percent of the normally gravitating matter in the universe

宇宙中 80% 受到引力作用的物质是

is dark matter.

暗物质。

Dark matter is dominant on the outskirts of galaxies,

暗物质主要聚集在星系的外围，

and it affects stellar motions on the edges.

从边缘影响星体的运动。

This effect is actually how Vera C. Rubin and Kent Ford

这种影响指引着薇拉·鲁宾 和肯特·福特（Kent Ford）

found the first substantive evidence for the existence of dark matter.

找到了第一个确凿证据 证明暗物质的存在。

What you're looking at here

你现在看到的是

is an artist's rendering of our own galaxy, the Milky Way,

我们的星系—— 银河系的艺术作品，

and it's enveloped in a halo of dark matter,

它由一圈暗物质包围，

represented here by a blue gas.

即图中的蓝色气体。

We believe that every single galaxy,

我们相信，每一个星系，

or almost every single galaxy,

或者说几乎每一个星系，

lives inside of a dark matter halo.

都被一圈暗物质包围着。

And we think that they're not alone.

我们也认为不仅仅这些星系。

The Milky Way itself has around 60 gravitationally bound satellite galaxies

单单银河系就有 大约 60 个伴星系

that are in its orbit.

由引力牵引在它的轨道上。

Some of these, you may have seen when observing the night sky,

有可能你在观星的时候 看到过其中一些，

or you may have heard of,

也有可能听说过它们，

like the Large Magellanic Cloud and the Small Magellanic Cloud.

比如大麦哲伦星云 和小麦哲伦星云。

Each of these satellites

每一个伴星系

lives inside of its own dark matter subhalo.

都被它们自己的 小暗物质圈包围。

So, like the invisible enby in their suit,

就像这个穿着西装的 非二元性别人士，

the presence of dark matter

暗物质的存在

is affecting how galaxies are distributed throughout space-time.

影响着星系在时空上分布的情况。

So we can also reverse-engineer where dark matter is --

我们也可以反过来 推算暗物质在哪里，

it's represented here by the bluish purple.

在这张图上用蓝紫色标示。

We can look at how images of galaxy clusters

我们可以从图上看到

are distorted, which tells us something

扭曲的星系团，展示了

about how dark matter is distorting space-time.

暗物质扭曲时空的一隅。

So we know something about how much dark matter there is,

我们了解了有多少暗物质，

and even how the dark matter is distributed,

暗物质如何分布，

but what kind of particle is it?

但是它到底是什么粒子呢？

So all that we know

我们知道的全部信息是

is that it's beyond standard-model physics.

它已经超出了标准模型物理。

It's not like any of the particles that we have ever seen

它与我们以往所见的或接触到的

or had any kind of contact with.

任何粒子都不一样，

Alright, so this seems like a potentially terrifying,

好吧，听起来有点吓人，

intractable problem,

是个无法攻克的难题，

because we're talking about something that we can't see,

因为我们讨论的是看不见、

something that we can't touch.

摸不着的东西。

You might be thinking,

你可能在想：

"OK, they haven't had many ideas about that over the years,

这么多年来对此都没什么想法，

because that just seems really hard."

因为看起来真的太难了。

Right?

对吧？

So here's the Venn diagram to end all Venn diagrams.

给大家看一张文氏图之王。

(Laughter)

（笑声）

[Theories of Dark Matter]

[暗物质的理论]

So I'll bet y'all a hundred dollars that you can't find a better one.

我敢赌一百块你找不到 一张更好的图，

At least according to me.

至少我找不到。

(Laughter)

（笑声）

So Tim Tait created this diagram

蒂姆·泰特（Tim Tait） 画了这张图，

to help us visualize just some of the hypotheses

让我们直观地看清一些

that physicists have had over the years to explain the dark matter problem

物理学家多年以来 用来解释暗物质问题的假设，

and how these ideas overlap with each other.

这些想法又如何互相重合。

So as you all can see, there's a lot happening here, right?

你可以看到 这有一大堆信息，对吧？

And hopefully, it's becoming increasingly clear

希望大家可以清晰地感受到

that this isn't just an astrophysics problem

这不仅是一个关于星系和星系团的

of galaxies and galaxy clusters,

天体物理学问题，

but this is also a particle physics problem.

还是一个粒子物理问题。

In order to understand what's happening on the largest scales,

为了从最宽广的视角了解现状，

we need to understand something very small,

我们必须从最微小的东西开始，

like a new particle,

比如一个新粒子，

or maybe primordial black holes.

或是原初黑洞。

So you've been looking at this for a moment,

你也看了一会儿了，

and you know what you're all really thinking is,

你们一定会想：

"What's Chanda's favorite dark matter candidate?"

昌达（Chanda）也就是我 最喜欢的暗物质是什么？

Right? This is what you're dying to know?

对吗？你们就这么想知道这个？

So, I'll end the suspense by telling you ...

让我来揭开谜底，

that my favorite candidate is something called the axion.

我最喜欢的暗物质 叫做轴子（axion）。

This is the hypothetical particle.

这是一种假想粒子。

And the first thing that I want to tell you about the axion

我想告诉你关于轴子的第一件事是

is that it was almost called the higglet ...

它差点就叫 Higglet 了 （史蒂文·温伯格命名）。

(Laughter)

（笑声）

And whoever chose "the axion" just completely blew it, OK?

选“轴子”这个名字的人 完全搞砸了好吗！

I'm pretty bummed about that.

我太失望了。

But the axion is a compelling particle, because it's a twofer:

但是轴子是一种非常值得注意的粒子， 因为它一石二鸟：

it addresses a problem that we already had,

它揭示了一个我们早已遇到的问题：

a conflict between theory and experiment

夸克物理学领域

in the realm of quark physics.

理论和实验的不一致。

"OK," you say, "but, like, how can I visualize it?"

你会说：“好吧， 那我们怎么想象它的样子呢？”

At this point in the talk, you should know better, right?

话已至此，你已经懂了吧？

Because to first approximation, dark matter is invisible.

总的来说，暗物质是不可见的。

(Laughter)

（笑声）

But I know you really want a visual,

我知道你们很想看可视材料，

so I'm going to give you one.

所以我现在就给你们看看。

Here's what it looks like to me, in my everyday work.

在我日常的工作里， 轴子就长这样。

(Laughter)

（笑声）

(Applause)

（掌声）

Which is to say, it's OK if this is unintuitive.

也就是说， 让你一头雾水也没关系。

(Laughter)

（笑声）

The universe is a wonderfully strange and fantastical place,

宇宙是一个千奇百怪、 五光十色的地方，

and that's why humans as a species have always wanted to study it.

这就是为什么人类作为一个物种， 长期以来执着于想要更了解它。

And this is why we have so much fun, trying to understand it.

也是为什么我们在这个过程中 一直享受其中。

So how are we going to go looking for the axion

那么，我们要如何寻找轴子

or any other dark matter particle?

或者其他暗物质粒子呢？

You might think that we have to use traditional particle physics approaches,

你可能觉得我们会用传统的 粒子物理学方法，

like colliders, where we smash particles together

比如粒子对撞机，对撞粒子

and see what comes out.

然后看看会发生什么。

But astrophysical signals have something to say.

但是天体物理学有了新发现。

Telescopes from across the electromagnetic spectrum --

覆盖电磁波谱各频段的望远镜，

for example, the proposed NASA facility,

比如 NASA 计划中的新设施

the STROBE-X X-ray space telescope --

STROBE-X X射线天文望远镜，

can help us potentially determine what exactly dark matter is.

让我们有机会确定 暗物质到底是什么。

But telescopes look at the very large.

但是望远镜是 从宏观视角来看宇宙的。

How can we use the extremely large to understand something so small?

我们如何通过宏观视角 了解微观物质呢？

Well, in the case of the axion,

拿轴子的例子来说，

it helps to pay attention to its quantum classification.

它让我们关注到了量子分类。

So all particles come in one of two quantum categories,

所有的粒子都会 被分为两个量子种类之一，

fermions and bosons.

费米子（fermion） 或玻色子（boson）。

So fermions, even when things get cold,

费米子就算在低温情况下

like to keep their distance from each other.

也会互相保持距离。

They're antisocial.

它们社恐。

That's how it is.

就是这样。

Bosons, on the other hand,

而玻色子

when they get below a critical temperature,

当温度降到临界温度以下，

they're like five-year-olds on a soccer field,

就会像足球场上的五岁小孩，

so they don't have a concept of formation,

不会整齐排好队，

they just bunch up together.

而是挤在一起。

So in technical terms,

我们从技术上

we call this the formation of a Bose-Einstein condensate,

将这种组合称为玻色–爱因斯坦凝聚 （Bose–Einstein condensate），

where all the particles come together and act like one superparticle.

所有粒子聚在一起 形成一个大粒子。

So importantly, axions are bosons,

值得一提的是， 轴子是玻色子，

and so now you have a sense of why I like working with them.

所以你知道为什么 我喜欢研究它了吧。

I'm completely enamored with the idea of axion Bose-Einstein condensates.

我被轴子的玻色–爱因斯坦凝聚 深深吸引。

So usually, we talk about creating these quantum states in the lab,

通常我们都是在实验室里 利用原子创造这些量子态，

using atoms,

but now,

但是如今，

we're talking about the possibility of new, maybe galaxy-scale

我们说的是或许有宇宙级规模的

Bose-Einstein condensates made out of dark matter.

全新暗物质玻色– 爱因斯坦凝聚的可能性。

So what you're looking at here

你现在看到的是

is a simulation developed by a team that I lead.

我带领的团队研发的模拟结果。

It's an axion condensate orbiting a central mass.

这是一个轴子凝聚态 围绕着一个中心团。

So it's like a subhalo orbiting its host galaxy.

就像光环环绕主星系。

Maybe the Large Magellanic Cloud orbiting the Milky Way.

比如大麦哲伦星云围绕银河系。

As you can see, over the age of the universe,

你可以看到随着宇宙进程的推进，

the subhalo starts to get to get torn apart,

光环逐渐被撕裂，

and what my team's work shows

我的团队展示的是

is that the way that this happens with axions

轴子的这个现象

is different than with other dark matter candidates,

和其他暗物质不一样，

because it goes into this special condensate state.

轴子会进入特殊的凝聚态。

Now imagine the possibility

想象一下，

that there's more than one type of dark matter candidate.

还有一种暗物质。

Maybe there's more than one type of dark matter particle?

也许不止有一种暗物质粒子呢？

How much richer this picture can be.

这张图会变得多么丰富啊。

There's no cosmic rule that says there can only be one.

没有宇宙公理规定只能有一种粒子。

So in the end,

最后，

I expect the universe to force us to reevaluate what we thought we knew.

我认为宇宙会让我们重新审视 我们以为自己知道的事。

[Making the invisible visible.]

[看见不可见]

When we honor the land and the sky ...

我们敬畏土地，敬畏天空，

as our galactic relations ...

它们是我们和宇宙的联系，

and their Indigenous stewards,

也是原生的管家，

it becomes possible for us to imagine

我们可以想象

new ways of being in good relations with each other.

互相和睦相处的新方式。

That's why I, as a Black queer person,

这也是为什么， 我作为一个黑人酷儿（Queer），

am so proud to follow in the footsteps of my ancestors,

非常自豪能够追寻祖先的足迹，

who studied and dreamed with the night sky,

他们研究、畅想夜空，

sometimes of freedom.

自由地遐想。

Astronomers like Harriet Tubman,

像哈丽雅特·塔布曼 （Harriet Tubman）这样的宇航员，

for whom the recently launched James Webb Space Telescope

才该是最近发射的 詹姆斯·韦布空间望远镜（JWST）

should be renamed.

应有的名字。

(Applause)

（掌声）

I honor the gay NASA employees who were persecuted

我尊敬那些 NASA 的 同性恋员工，

under the leadership of JWST's namesake,

他们在詹姆斯·韦布 在职领导期间遭到起诉，

even as I share in the tremendous community-wide excitement

即使我刚才无比激动地给大家分享了

for what that facility is going to teach us about dark matter.

这个设施让我们更了解了暗物质。

And I honor the memory of Vera C. Rubin,

我缅怀宇航员薇拉·鲁宾，

the astronomer who first asked me,

她是第一个问我这个

as a young, terrified graduate student,

年轻且畏缩的研究生

"How do you think we should solve the dark matter problem?"

“你觉得我们该如何解决暗物质问题？” 这个问题的人。

We live in an amazing time to be doing dark matter research.

我们身处研究暗物质的绝佳时期。

Over the next decade,

在接下来的十年里，

we're going to see the universe with incredible accuracy and clarity

在天上地下的新型望远镜的帮助下，

thanks to these new telescopes on the ground and in the sky.

我们会以前所未有的精度和清晰度 看清宇宙。

We'll probably get some answers,

我们也许会有一些答案，

but we're going to get a host of new questions.

但是我们会有很多的新问题。

And my team? We're going to be ready.

我的团队会怎么样？ 我们会准备好的。

So the search for dark matter is on.

寻找暗物质之旅开始了。

What's your favorite candidate?

你最喜欢什么暗物质？

(Laughter)

（笑声）

If it's not an axion, you better fix that.

如果不是轴子， 我劝你再考虑考虑你的答案。

(Laughter)

（笑声）

Thank you.

谢谢。

(Cheers and applause)

（欢呼与掌声）