How Fast Is the Universe Really Expanding?

事实上，我确信自己搞错了什么，因为，是的。

In fact, I was sure that I did something wrong because Yeah.

毕竟上过你的数学课，对吧，我很清楚自己容易犯错。

Having taken your math class, right, I was very familiar with making mistakes.

你知道，作为学生，你就是这样，尝试做事情，然后一遍又一遍地得到错误答案，接着再努力找自己的错误。

You know, this is what you do as a student is you try to do things and you get the wrong answer over and over and over, and then you try to find your mistake.

所以，是的，那段时间确实很让人担心。

And so, yeah, it was very worrisome for a while.

所以我做了很多交叉检查，因为自己发现错误总比最后不得不告诉团队，让他们发现错误要好。

So I did a lot of cross checks because it's always better to find your own mistake than finally willing to share with the team and let them find the mistake.

然后，你知道，每个人都尽可能交叉检查了一切，但我们就是找不到错误。

And then, you know, everybody cross checked everything we could, and we could not find the mistake.

然后我们开始接受这个可能性，即这是真实的，这是天空中的信号，而且背后有深刻的物理学原因。

And then we started getting comfortable with the possibility that it was real, that this was the signal on the sky, and that there was a deep physics reason why this was.

那就是，在爱因斯坦的广义相对论中，引力还有另一种选择。

And that is that in Einstein's theory of general relativity, gravity has another option.

它还有另一种机制。

It has another kind of gear.

你知道，在牛顿的理论里，引力只会吸引。

You know, in Newton's theory, it's only attractive.

它只会把东西拉在一起。

It only pulls stuff together.

对吧？

Right?

而在爱因斯坦的理论中，真空的引力可以是排斥的，他称之为宇宙常数，甚至一度用它来试图让宇宙保持平衡，当时他认为宇宙没有在膨胀。

In Einstein's theory, the gravity of empty space can be repulsive, something he called the cosmological constant and even invoked at one point to try to keep the universe in balance when he thought it wasn't expanding.

这个想法一直存在。

And it's always been around.

物理学家后来将其解释为太空真空的能量，也就是我们现在所说的暗能量，它可能产生相反的效果。

Physicists later interpreted this as the energy of the vacuum of space or what we now call dark energy, and it can go the other way.

所以我们得出的解释是，显然爱因斯坦发现了什么，引入这个项能很好地拟合数据。

And so the interpretation we came to was that apparently Einstein was onto something and that introducing this term gave a good fit to the data.

把它去掉的话，数据拟合效果就不好了。

Leaving it out gave a bad fit to the data.

确实。

Yeah.

这真的很令人惊叹。

It's quite amazing.

大家总觉得爱因斯坦不会犯错，因为他曾 famously 把宇宙学常数称为他最大的失误，原因正如亚当所说的那样。

It was like Einstein couldn't make a mistake because he famously called the cosmological constant his greatest blunder for the reason Adam said.

他最初把这个项加进方程里，是为了让宇宙保持不膨胀的状态。

He originally put it into his equation to try to make the universe not expand.

对吧？

Right?

但这种平衡非常脆弱。

But it's very precariously balanced.

所以如果平衡不够完美，宇宙就无法维持静止状态。

And so if the balance isn't perfect, it doesn't make the universe static.

它实际上加速了膨胀。

It actually accelerates the expansion.

嗯，我在想，宇宙学常数可能是那些了解科学史的人会记得的东西，但它并不是标准广义相对论课程的一部分，对吧？

Well, I'm wondering, the cosmological constant was something maybe people who knew history of science would remember, but it wasn't part of standard general relativity coursework or anything, right?

在90年代它是不是有点冷门？

Wasn't it sort of obscure in the '90s?

还是说它一直都在那里，比如我们需要考虑它？

Or was it always there as like we need to think about it?

我觉得这是个好问题。

I think that's a good question.

它可能对理论物理学家来说一直都在，他们什么都会尝试。

It was probably there for theorists who would try anything.

对。

Uh-huh.

所以，基本上，人们更多是在早期宇宙暴胀这样的背景下考虑宇宙学常数。

So, essentially, people were thinking about the cosmological constant more in the context of things like inflation in the early universe.

但当时的想法是，它会蒸发掉，衰变成构成原始汤的所有粒子，根本不该留到今天。

But then the idea was it would evaporate away and it would decay into all the particles that made up the primordial soup, and it had no business hanging around today.

这确实很有意思，这些暴胀理论让人们对重新思考宇宙学常数变得更容易接受。

That's really interesting to think about that, that these inflationary scenarios had sort of softened people up to starting to think again about the cosmological constant.

对。

Yeah.

我觉得诺贝尔奖颁给加速膨胀这个发现也特别有意思。

I And think it's really interesting the Nobel Prize was for the accelerated expansion.

它没提到暗能量或者宇宙学常数。

It doesn't mention dark energy or a cosmological constant.

他们拿诺贝尔奖可不是因为这个。

That's not what they got the Nobel Prize for.

他们是因为对超新星的观测以及加速膨胀现象获奖的，这真的很有意思。

They got it for the observations of the supernovae, which is really interesting, and the accelerated expansion.

我觉得这也符合诺贝尔奖的评选理念，也就是只奖励那些经过验证的成果。

And I think that's consistent with the Nobel philosophy that they award prizes for verified results.

现在我们对暗能量一无所知，所以没有诺贝尔奖颁给它。

Now, we don't know anything about dark energy, so there's no Nobel Prize for that.

我们最多只能给它起个临时的名字。

The best we can do is give it this proxy name.

除了叫它暗能量，猜测它可能是真空的能量，也可能不是。

Other than calling it dark energy and musing that maybe it's the energy of empty space, maybe it's not.

所以，这个奖还得留着，等哪天有人真正发现了暗能量是什么，才能颁出去。

So, it remains to be an award to be doled out one day if somebody actually discovers what the dark energy is.

你说得对，诺贝尔奖这事儿，你看爱因斯坦的相对论，他也没因为狭义或广义相对论拿诺贝尔奖。

That's a really good point that the Nobel I mean, when we talk about Einstein in general relativity, famously, he didn't get a Nobel Prize for either special or general relativity.

对吧？

Right?

他拿诺贝尔奖的时候，我忍不住笑，因为他太确信自己能拿奖，都敢拿它来许诺。你不知道这个故事吗？

His Nobel Prize I'm just chuckling because he was so sure it was coming that he could promise it Do to his you not know this story?

我不知道。

I do not know this.

他承诺把诺贝尔奖的奖金给他第一任妻子，因为他知道离婚后她会需要这笔钱。

He promised the money from his Nobel Prize to come to his first wife, knowing when he got divorced that she would need some money.

他得奖不是因为相对论。

He didn't get it for relativity.

他是因为对光电效应的解释才得奖的。

He got it for, you know, his explanation of the photoelectric effect.

对的。

Mhmm.

是啊。

Yeah.

太不可思议了。

Incredible.

但这就是

But it's

诺贝尔委员会用的一种很有意思的评判标准，他们想要的正是你说的那种，能被实验或观测验证、站得住脚的物理学。

an interesting sort of aesthetic or criterion that the Nobel Commission uses that they want, as you say, verifiable, experimental, or observationally solid physics.

我觉得这样很合适。

And I think that's appropriate.

本来就该这样。

That's how it should be.

好的，没问题。

Well, alright.

说到我们故事中的转折，你知道，如果宇宙常数是第一个转折，那么事实证明，在我们休息之后会听到，还有另一个转折即将到来。

In connection with plot twists in our story, you know, if the cosmological constant was the first twist, it turns out, as we're gonna hear after the break, that there is another plot twist coming.

太好了。

Great.

真吊人胃口。

Suspense.

欢迎回到《为什么的乐趣》。

Welcome back to the Joy of Why.

我们正在和约翰霍普金斯大学的天体物理学家亚当·里斯讨论宇宙加速膨胀的问题。

We're speaking with Johns Hopkins astrophysicist Adam Riess about the accelerating expansion of the universe.

所以你提到了宇宙常数。

So you mentioned the cosmological constant.

这常常要追溯到爱因斯坦本人，在他的记号中，他用希腊字母λ来插入一个有些人轻蔑或讽刺地称为“凑数因子”的东西，但这是广义相对论方程所允许的。

It's often going back to Einstein himself in his notation, he used the Greek letter lambda to insert what some people dismissively or sarcastically will call a fudge factor, but it was something that was allowed by the equations of general relativity.

正如你所说，爱因斯坦起初想要它，因为他当时无法相信宇宙在膨胀。

As you say, Einstein wanted it at first because he couldn't believe at the time that the universe was expanding.

对。

Right.

你得理解爱因斯坦，他问当时的实验天文学家，宇宙在做什么？

You have to understand Einstein, he asked experimentalist astronomers of the day, what is the universe doing?

他们告诉他，天体的运动非常非常小，他们之所以这么说，是因为那时甚至还没有发现星系在银河系之外。

And they told him that the motions of things were very, very small, and the reason they did was because at that time, it was before the discovery even that galaxies were outside the Milky Way.

所以天文学家认为宇宙就是银河系本身，当他问银河系在做什么，是在膨胀还是收缩时，

And so astronomers thought of the universe as the Milky Way itself, and when he asked about what the Milky Way was doing, was it expanding, contracting?

他们说，运动相当温和。

They were like, the motions are pretty modest.

看起来既没有膨胀也没有收缩。

Doesn't seem like it's expanding or contracting.

收缩。

Contracting.

这对他来说肯定很困惑，因为你想啊，如果你有一堆质量体，它们处于静止状态，然后你放手，对吧，它们就会互相吸引靠拢。

And this would have been confusing to him because, you know, if you had a collection of masses and it was static and you let go, right, they would fall together.

那么是什么让它们保持静止的呢？

And so what was keeping it static?

所以正如你所说，他在方程里看到了一个可以抵消引力吸引的选项，于是他就用了这个，按照我们现在的说法，把它设定为宇宙保持静态的边界条件。

And so he saw, as you said in his equations, that there was an option for something to counterbalance the attractive gravity, and so he took it and set it to his, you know, as we would say, boundary condition that the universe be static.

当然，这里有两个问题。

There were two problems, of course.

一个是宇宙其实在膨胀，所以那个静态的假设并不成立。

One was the universe is expanding, and so that's not the right boundary condition.

另一个问题是，这种平衡是不稳定的。

The other is it's an unstable equilibrium.

这就像把一颗弹珠放在篮球顶上。

It's like taking a marble and putting it on top of a basketball.

是的。

Yes.

理论上，它可以待在那里，但如果你轻轻一推，只要有微小的偏差，它就会朝某个方向滚走。

In principle, it could sit there, but if you push it off, if there's a slight difference, it'll run away in one direction or the other.

而且

And

所以当他看到宇宙在膨胀，当哈勃和其他人证明了这一点时，他著名地说这是他职业生涯中最大的错误，就是引入了这个概念，然而现在却无法摆脱它。

so when he saw the universe was expanding, when Hubble and others showed it, he famously said this was the biggest blunder of his career was to introduce this concept, and yet there's no getting rid of it.

就像很多数学和物理中的东西一样，它被允许出现在方程中，除非你有证据表明它不可能存在。

Like a lot of mathematics and physics, it's allowed to be in the equations unless you have some knowledge that it can't exist.

所以大约八十年后，我们在这里说，实际上，宇宙似乎在加速膨胀，这就像那种排斥性的引力现在真的战胜了物质的吸引性引力。

And so here we were some, oh, eighty years later saying, actually, it looks like the universe is accelerating, which would be as if that repulsive type gravity actually was now winning over the attractive gravity of matter.

我听过一句有趣的话，不知道是谁说的，那就是：未被禁止的就是必须的。

There's that funny saying I've heard, I'm not sure who to attribute it to, that what is not forbidden is compulsory.

你懂我的意思吧？

You know?

就像在这种情况里，那个宇宙学常数项并没有被方程所禁止。

Like in something like this where the lambda term, the cosmological constant, was not forbidden by the equations.

方程是允许它的存在，而且事实上，我们现在认为确实有类似的东西。

It was permitted by them, and in fact, now we think there is something like that.

正如你所说，现在的术语通常叫作暗能量，但我们可以深入探讨一下，去挖个深坑问问自己：这暗能量到底是什么？

As you say, the modern term is often dark energy, but we could go down a big rabbit hole of asking ourselves, what is this dark energy?

不过我想换个方向，聊聊Lambda冷暗物质模型，也就是ΛCDM模型。我知道你接下来肯定会说这个模型可能需要做些调整，甚至可能不止是微调，但咱们先来说说它为什么是一个非常有意思、非常强大的标准模型吧。

But I think I would like to go in a different direction to talk about the Lambda cold dark matter model, the Lambda CDM model, because I mean, I realize that you're gonna wanna tell us there may be some tweaks needed to it or maybe more than tweaks, but why don't we first make the case that this is a really interesting, powerful standard model.

给我们讲讲这个模型到底是什么，以及它为什么这么有说服力。

Tell us what this model is and what makes it compelling.

它有哪些特别出色的成就？

What are some of its great successes?

好的。

Sure.

当我们构建所谓的宇宙模型时，首先我们讨论的是宇宙由什么组成，就像做一道菜的配方一样，那么这些成分是什么？

When we build what we call a model of the universe, we to first order, we're talking about what it's made of, what's the recipe if you wanted to make one, and so what is the stuff?

然后我们通常也会把物理定律作为其中的一部分来讨论。

Then we also usually talk about the laws of physics as part of that.

但就宇宙而言，人们熟悉的是元素周期表中的元素，那只是很小的一部分。

But in the case of the universe, what people are familiar with, the elements in the periodic table of elements, that's the small stuff.

那大约只占宇宙的4%，其余的都是暗的。

That's like 4% of the universe, And the rest is dark.

暗的意思是它不发光，所以我们无法直接看到它。

Dark meaning it doesn't emit light, and so we can't see it directly.

我们只能通过它的引力来推断它的存在。

We have to infer it by its gravity.

所以从20世纪30年代到70年代及以后，天文学家逐渐认识到宇宙中有大量的物质具有引力吸引作用，但却是暗的，不发光，这就是所谓的暗物质。

And so from the nineteen thirties to the nineteen seventies and later, astronomers came to understand that there was a lot of matter in the universe that had attractive gravity but was dark, was not emitting light called dark matter.

它使得星系的旋转速度远快于可见物质所预示的速度。

It makes galaxies spin much faster than the luminous matter would indicate.

否则，恒星就会从星系中飞散出去。

Otherwise, stars would just zing away from their galaxies.

它让星系在星系团中围绕其他星系运行，同样，如果没有额外的引力粘合剂，它们就会飞散。

It makes galaxies orbit other galaxies in clusters, which again, they would just fly away if there wasn't the extra gravitational glue.

还有光的弯曲，称为引力透镜效应。

There's bending of light called lensing.

所有这些技术让我们能够确定，宇宙大约有25%是暗物质，大约26%是暗能量，大约4%是普通物质，所以加起来是30%。

All of these techniques allow us to figure out that the universe is about 25% dark matter and about maybe 26% and about 4% normal matter, so 30% there.

然后，我们在九十年代的结果，以及随后对宇宙微波背景辐射的观测，表明剩下的70%是这种暗能量。

And then with our results in the nineteen nineties and then quickly followed up by observations of the cosmic microwave background radiation showed the other 70% is this dark energy.

所以我们得到了一个完整的宇宙模型，它解释了我们所看到的一切，但其中96%是暗的。

So we get a sort of full universe that explains what we see, but 96% of it is dark.

需要明确的是，当我们谈论它时，我们谈论的是它的引力作用。

And to be clear, when we talk about it, we talk about its sort of gravitational action.

但我们真正不谈论的，或者说还不能谈论的，是微观物理，那些细节。

But what we don't talk about really or can yet is the microphysics, the details.

暗物质，我们认为它是一种粒子，但我们不知道这种粒子的本质。

Dark matter, we think it's a particle, but we don't know the nature of the particle.

我们不知道它是否稳定，也不知道它有没有其他的相互作用。

We don't know if it's stable, if it has other interactions.

至于暗能量，我们通常只是笼统地说它是真空的能量，但做量子力学计算的人试着估算这个能量应该是多少，结果算出来的答案和我们观测到的差了120个数量级。

For dark energy, we sort of generally wave our hands and say it's the energy of the vacuum, but people who do quantum mechanical calculations try to estimate how much that should be, and they get an answer that's a 120 orders of magnitude off from what we get.

所以我们目前拥有的，我觉得可以说是一个解释性的故事，一个建立在很多坚实物理概念之上的唯象模型，但它终究还是一个模型。

So what what we have is a very good, I'm gonna say just so story, you know, a phenomenological model grounded on lots of strong physics concepts, but it's still a model.

它不是物理本身。

It's not the physics itself.

它也不是对这些东西本身的描述。

It's not a description of those items themselves.

我们目前只能用最朴素、最标准的形态来对待暗物质和暗能量，因为我们还没有...

We, for now, treat each of those dark matter, dark energy in their most vanilla form because we haven't yet

对。

Uh-huh.

还没往上面撒糖珠呢，不过我们还在观察。

Done any sprinkles on them, but we're looking.

最基础的形式。

Vanilla form.

我明白你的意思了。

I see what you mean.

你刚才介绍了一些模型里的参数。

You were describing some of the parameters that go into the model.

也就是说，即便我们还没搞清楚暗能量到底是什么，也能估算出它在宇宙总能量预算里占了多少。

That is, without saying what dark energy is, we can estimate what its contribution is to the budget, the energy budget of the universe.

这里面包括暗物质的量、发光物质的量，还有几个其他参数构成了这个标准模型。支持它的人——我觉得这也是目前的共识，认为这是我们要最好的模型，虽然它毕竟只是个模型——但它能解释很多东西。

There's the amount of dark matter, the amount of luminous matter, and there's a few other parameters that go into this standard model, but the advocates for it, which I think is the consensus that it's our best model, though it is a model, right, that it it explains a lot of things.

确实如此。

It absolutely does.

所以它能解释很多现象。

So it explains many things.

它能解释为什么宇宙在膨胀。

It explains why the universe is expanding.

它能解释为什么轻元素的化学丰度是现在这个样子。

It explains why we have the particular chemical abundances of light elements.

它能解释我们观测到的宇宙微波背景辐射，包括其中的涨落以及特定的涨落谱；它还能预测宇宙的演化历史，比如早期有一个减速阶段，那时引力占主导，这使得星系团、行星等结构的形成成为可能；之后还有一个加速阶段，随着空间膨胀导致物质密度稀释，暗能量开始占据主导地位。

It explains the cosmic microwave background radiation that we see, the fluctuations in it that we see, the particular spectrum of fluctuations that we see, then it predicts an expansion history of the universe, including a phase early on when it is decelerating and dominated by a track of gravity, which allows structures to form like clusters of galaxies and planets and all of that good stuff, and then a later phase when it would accelerate, when it's dominated by this dark energy as the matter is diluted by the expansion of space.

所以它能解释我们看到的很多现象，这也是理所当然的，因为它是基于我们对宇宙的观测逐步发展起来的，我们也根据观测结果不断对它进行修正和完善。

So it explains a lot of what we see, and it should because it is developed as we look at the universe, and we have added to it or changed it to match what we see.

所以我会说，直到21世纪初，甚至到2010年左右，这个模型真的能解释一切。

And so I would say up until the early two thousands, maybe even 2010, it fit everything, really.

但因为我们有这些深层的疑问，我们不只是在找一个模型，而是在寻找背后的物理机制，所以人们一直在做更精密的实验。因为科学的本质就是这样：你有一个模型，它是目前对现实最好的近似，但它不可避免地会有一些局限性，也许是你还没发现或没理解的地方。

But because we have these deep questions, we're not just looking for a model, we're looking for the physics, people continue to do more precise experiments because the nature of science has always been that you have a model and it's the best approximation for reality, but inevitably it has some shortcomings, which maybe you haven't seen yet or understood.

以我们常说的ΛCDM模型为例，它的局限部分来自理论层面，因为我们还不了解那些暗物质和暗能量的本质。

In the case of Lambda CDM, as we call it, the shortcomings are partly theoretical that we don't understand these dark parts.

但在观测方面，它表现得非常出色。

But observationally, it was excellent.

然后随着2010年代的推进，人们确实尝试做越来越精确的实验来检验这个模型，因为我们想弄清楚，暗能量真的是一个常数，还是它会随时间变化？

And then as the twenty tens went on, people did try to do more and more precise experiments to test this model because we wanna tease out, is dark energy really a constant, or is it something that varies over time?

宇宙中有一些先例，比如大爆炸后不久有一个我们称之为暴胀的时期，那也可能是一种暗能量，一种不同的暗能量，它随时间出现又消失。

There's some precedent in the universe for there was an episode shortly after the big bang we call inflation that also would have been dark energy, a different dark energy that would have appeared and disappeared over time.

我们在想，今天的暗能量是在消失还是在变强？

We're wondering, is our dark energy today disappearing or getting stronger?

我们想知道这一点。

We would like to know that.

我们想更多地了解暗物质的本质。

We would like to know more about the nature of dark matter.

因此，虽然我们做理论，我们也做更好的实验来告诉我们更多信息。

And so therefore, while we do theory, we also do better experiments to try to tell us more.

我觉得同时欣赏成功和不足是非常有趣的。

I think it's super interesting to appreciate the successes and the gaps together.

对吧？

Right?

因为我们今天要讲的故事，核心就是这些不一致之处，但至少对我来说，只有当你理解了理论本该有多好时，这些不一致才真正令人印象深刻。

Because the rest of the story that we wanna tell here is one of discrepancies, but they only become really impressive, at least to me, when you understand, like, what you expect in terms of how good the theory is.

到目前为止，这个模型在1%的精度内都表现良好，正如你所说，通过调整那些你无法用其他方式估计的参数。

Up till now, the model has been good to within 1%, as you say, by tuning parameters that you can't otherwise estimate.

但即便如此，通过这种调整，你也能解释很多不同的现象，精度都在1%以内。

But still, with that tuning, you can account for lots of different things to within 1%.

大家应该明白，这个模型是非常成功的。

People should understand this model is very successful.

它解释了很多东西。

It explains a lot.

它作为标准模型已经大约二十五年了，并且经受住了实验精度多次重大提升的考验。

It's been the standard model for about twenty five years, and it has survived through many traumatic advances in the precision of experiments.

但正如我想我们接下来会讨论的，我们也开始看到模型出现了一些裂痕的迹象，你知道，我们还在努力应对这些迹象，我想说。

But as I think we'll talk about as well, we've begun to see some hints of cracks in the model as well, which, you know, we're still wrestling with, I would say.

那我们现在就进入这个话题吧，因为这是……而且我觉得你的个人经历中这一点也很引人入胜。

So let's go there now because this is the and I find this compelling in your own biography.

说真的，你真是个真正的科学家，如果不介意的话，我想在这儿夸你几句。

Like, it's what a true scientist you are, if you don't mind me heaping some praise on you here.

你提到的那个年份，你说二零一零年左右，人们开始注意到了。

The year that you mentioned, you said twenty tens, people started noticing.

是你和其他人开始注意到这些问题的。

This is you and other people started noticing.

你要去瑞典领诺贝尔奖了，你还那么年轻，才四十一岁左右，但你并不满足。

And you're going to Sweden, you're getting the Nobel Prize, you're still a kid, you're just 41 years old or something, and you're not satisfied.

你还没准备好只去做行政工作。

You're not ready to just become an administrator.

你还想继续做科学研究。

You wanna keep doing science.

对。

Yeah.

毕竟，搞科研挺有意思的。

Well, science is fun.

对吧？

Right?

所以我当时41岁，很多人就问，那你接下来打算干嘛呢？

So I was 41 and, you know, a lot of people said, oh, what are you gonna do now?

你知道的。

You know?

我看了看其他诺贝尔奖得主，不幸的是，他们的平均年龄已经涨到了七十岁左右。

And I looked at the other Nobel laureates, and unfortunately, the average age has evolved up to about your seventies.

所以普通人可能会觉得，哎呀，我的学术生涯已经走完了。

So the average person is like, well, I've already done my academic career.

我都退休了，这就相当于荣誉巡讲，去到处做演讲之类的。

I'm emeritus, so this is like a victory lap I'm gonna do and go give talks and things like that.

但我当时才41岁，这不仅仅是时间太早的问题。

But I was 41, and it was too not just too soon.

对我来说，那样做并且停下我真正正在做的事情，完全毫无吸引力。

It completely unappealing to me to do that and to stop what I was actually doing.

我当时正在用哈勃太空望远镜。

I mean, I was in the middle of using the Hubble Space Telescope.

这多酷啊？

How cool is that?

观察四颗遥远的爆炸恒星和脉动恒星，绘制宇宙膨胀的历史。

To look at four distant exploding stars and pulsating stars and mapping the expansion history of the universe.

我决定从斯德哥尔摩回来后，唯一的出路就是尽量推掉那些演讲，真正专注于科学研究，因为你知道，一旦停下来，就很难再回去了。

I decided that the only way forward after that trip to Stockholm was to try to push out as much as I could all those speaking things and and try to really focus on the science because, you know, once you stop, you know, it's hard to go back.

好吧。

Well, okay.

所以这就是情节变得复杂的地方。

So this is where the plot thickens.

你开始进行这些改进的测量，然后告诉我们你发现了什么，以及张力是如何进入我们的故事的。

You start making these improved measurements, and then so tell us what you found and where tension enters our drama here.

我们有一个新模型，Lambda CDM，它包含这些部分：暗物质、暗能量。

So we have a new model, Lambda CDM, and it has these parts, dark matter, dark energy.

这些都很好。

That's all great.

问题就变成了，这种暗能量的本质是什么？

And the question became, what is the nature of this dark energy?

作为物理学家，我们会说，好的。

And so as physicists, we say, okay.

让我们找一个可以测量的数字或属性，它会告诉我们一些关于它的信息。

Let's find a number or a property of it that we can measure, and it will tell us something about it.

暗能量产生引力的方式，关键在于它的状态方程，即压力与能量密度的比值。

And so in the way that dark energy produces gravity, what matters is what's called its equation of state, the ratio of its pressure to its energy density.

这个数字叫做w。

And this number is called w.

如果它是宇宙学常数，那么w将始终为负一。

And so if it's a cosmological constant, then w will be minus one for all time.

如果它是空间中的某种场，想想你熟悉的场，比如电场、磁场，这会是一个不同的场，但它会有能量，它的能量会像暗能量一样起作用，那么它可能不是负一。

And if it's some kind of field in space, think of a field you know of, the electric field, the magnetic field, this would be a different field, but it would have energy and its energy would act like dark energy, then it might not be minus one.

也可能是别的值。

It might be some other.

为了研究这个w值，我们投入了很多精力，建造了太空任务。

There's been a lot of effort in space missions built to try to study this w number.

我发现一个比较好的方法就是测量哈勃常数，也就是宇宙当前的膨胀速率，然后把它和根据Lambda CDM模型以及来自WMAP和PLANCK这些NASA和ESA的新太空卫星的精确宇宙微波背景数据所预测的值进行比较。

And I saw one of the better ways to do this would be to measure the Hubble constant, the actual present expansion rate of the universe, and compare that to the predicted value it should have following both this model, Lambda CDM, and this exquisite cosmic microwave background data that was coming from new space satellites like WMAP and PLANKE flown by NASA and ESA.

我启动了一个名为SHOES的新项目，利用哈勃太空望远镜，尝试把测量精度从之前的10%提高到1%。

And I began a new project called SHOES to leverage the Hubble Space Telescope and try to improve the measurement from 10% precision, which it had been before, to try to reach 1% precision.

起初，进展非常顺利。

And at first, it was going really well.

我们得到的测量结果不确定性越来越小，而且大部分都和宇宙微波背景的预测相符。

We were getting measurements that were smaller and smaller uncertainties, and they were matching the cosmic microwave background to to the most part.

然后，有趣的事情发生了。

And then a funny thing happened.

那是大约十多年前的事了。

It was about little more than ten years ago.

那是2013年。

It was 2013.

后来欧空局的新一代宇宙微波背景辐射实验——普朗克，技术非常尖端，结果出来以后对哈勃常数的预测值做了相当大的调整。

And Planck, the new cosmic microwave background experiment from the European Space Agency, very state of the art came out with a pretty large adjustment of the predicted value of the Hubble constant.

我们的测量结果一直是在七十出头，用的是天文学家那些挺晦涩的单位，每秒每兆秒差距多少公里。这个数看起来很怪，但实际上它是时间的倒数。

Our measurements typically have been in the low seventies in these arcane units that astronomers use, kilometers per second per megaparsec, which is a very strange number, but it's the inverse of time.

所以如果你把它倒过来，就能大体看出宇宙的年龄。

And so if you invert it, it it actually tells you the approximate age of the universe.

过去用本地测量得到的经典数值一直是七十出头，七十到七十五之间，我们当时也收敛在73左右，正负2，这跟之前宇宙微波背景的数据看起来还挺吻合的。

And so the classic number from local measurements had always been in the low seventies, 70 to 75, and we were honing in on around 73 plus or minus two, and that all looked okay with the previous cosmic microwave background data.

但是更好精度的宇宙微波背景数据一出来，突然就是：‘坏了，不是这样。’

But when better cosmic microwave background data came out, it was suddenly, oh, no.

更像67左右，正负零点五。

It's gotta be more like 67 plus or minus point five.

听起来这差别好像不大。

Now this might sound like a small difference.

回到你之前说的，这确实是个好模型。

Again, back to your statement earlier, this is a good model.

我们是在从宇宙的另一端穿针引线。

We're trying to thread a needle from the other side of the universe.

你知道，我们从大爆炸那一刻开始，想知道宇宙在一百三十到一百四十亿年后会膨胀得多快，结果我们差了百分之八到九。

You know, we're starting at the moment of the big bang and asking how fast the universe will be expanding some thirteen to fourteen billion years later, and we're like, we're off by eight or 9%.

在几乎任何其他领域，这都算是相当不错的预测了。但我们对此很严谨，我们的误差棒很小，他们的误差棒也很小。

That's pretty good predictive work, I would say, in almost any other field, But we're rigorous about this, and our error bars are small, and their error bars are small.

连接它们的唯一东西就是理论，也就是模型，它告诉我们如何解释宇宙从大爆炸到现在的轨迹，所以总得有个说法。

And the only thing connecting them is the theory, the model, tells us how to explain the trajectory of the universe from the Big Bang to the present time, and something has to give.

要么是宇宙微波背景辐射的测量错了，要么是本地测量错了，要么是连接它们的故事不太对。

Either the cosmic microwave background measurement is wrong or the local measurement is wrong or the story that connects them is not quite right.

过去十年我们都在深入研究，非常仔细地重新做测量。

We've all been doing deep dives over the last decade, redoing the measurements very carefully.

我现在用的是詹姆斯·韦伯太空望远镜，而不是哈勃太空望远镜，但得到的答案是一样的。

I've been using the James Webb Space Telescope now instead of the Hubble Space Telescope, but getting the same answer.

很多人一直在宇宙微波背景辐射方面做了大量工作，也得到了同样的结果。

People have been doing a lot of work on the cosmic microwave background side, getting the same answer.

整个科学界都仔细研究过这个问题。

The community has poured over this.

大家反复审查过。

It's scrutinized over it.

所以它有了个名字叫哈勃张力，听起来就是这样。

And so it's gotten a name called the Hubble tension, which is as it sounds.

这是基于模型和早期宇宙所预期的哈勃常数与实际观测值之间的紧张关系。

It's a tension between what you think the Hubble concept should be based on the model and the early universe and what it actually appears to be.

而且它已经超过了我们所说的五西格玛，用物理学的说法就是，差异是实验误差棒的五倍，到了这个程度我们就会说，嘿。

And it is surpassed what we call five sigma, which in physics talk means the discrepancy is five times larger than the error bar on the experiment, which is the point at which we say, hey.

肯定有什么不对劲。

Something's going on.

所以我觉得，试图弄清楚那个不对劲的东西是什么，真的很有趣。

And so it's been a lot of fun, I would say, to try to figure out what that something is.

总结得太棒了。

Fantastic summary.

太完美了。

That's perfect.

你刚才讲了很多关于宇宙微波背景的内容，我们一直把它当作常识。

You've talked a lot about the cosmic microwave background, which we've been assuming is standard knowledge.

我想澄清一下。

I wanna clarify.

我们是在给宇宙拍婴儿照，就像你之前提到的门框标记一样。

We're taking a baby picture of the universe, like you talked earlier about the door jam.

对。

Right.

对。

Right.

对。

Right.

所以我知道，我66岁时身高是6英尺1英寸。

So I know at age 66, I'm six one.

现在想象一下，当我在医院里，我甚至还不满一天大。

Now imagine when I was in the hospital, and I'm not even one day old.

我躺在婴儿床里。

I'm in the baby crib.

如果你看着我这个婴儿，然后你说，是的。

If you had looked at me as that little baby and then you said, yeah.

但我能告诉你史蒂文66岁时会有多高，因为我有一个很棒的模型，我要预测他的身高。

But I can tell how tall Steven is gonna be when he's 66 because I have this great model, and I'm gonna predict his height.

我有一个

I have a

很棒的模型。

great model.

他的身高误差在8%到9%以内。对吧。

His height to within eight or 9% Right.

当他66岁时，从这个一天大的婴儿预测。

When he's 66 from this one day old baby.

这就是宇宙学家们试图比较的。

That's what the cosmologists are trying to compare.

研究婴儿的是Lambda CDM团队。

The people doing the baby are the Lambda CDM people.

对。

Correct.

而你正在做

And you're doing

对。

Right.

我现在正在测量门框，模型说，在这种情况下，嘿。

I'm measuring door jam right now, and the model said, you know, in this case, hey.

史蒂夫应该是六英尺一英寸，但我们得出的结果是，他更像七英尺高。

Steve was supposed to be six foot one, and we're coming out with, well, he's more like seven foot tall.

而且你可能会觉得，这也许挺有趣的，但你会想，这真的完全出乎意料，你居然有七英尺高。

And you're which, you know, might be fun, but you're like, that doesn't that that is really would be truly unexpected for you to be seven feet tall.

你可能会说，嘿。

And you might say, hey.

也许有人给你拍婴儿照的时候搞错了，或者他们用的卷尺不对什么的。

Maybe somebody took that baby picture of you wrong, or they were using the wrong tape measure or something.

这些是我们知道怎么处理的事情，我们知道如何用不同的望远镜、让不同的小组、用不同的工具和不同的示踪物来反复检查实验。

And that's the stuff we sort of know how to do, that we know how to double check experiments, do it with different telescopes, have different groups of people do it, different tools, different tracers.

所以这项工作已经进行了十年，没有人发现测量有什么问题。

So that work has gone on for a decade, and nobody has found the problem with the measurements.

然后你开始怀疑，是不是成长图表，也就是我们告诉模型的那个故事，出了问题？

And so then you start to wonder, is it the growth chart, the story that we tell the model?

一方面，你会说，那应该很容易摆弄。

And on the one hand, you say, that should be pretty easy to play with.

你告诉我这些暗物质的东西太普通了，你都不知道暗能量和暗物质是什么。

You told me this dark stuff is so vanilla that you don't know what dark energy and dark matter are.

你不能调一些参数，改改那些特征来改变它吗？

Can't you just turn some knobs, some features on those that changed it?

给自己在青少年时期多几次生长突增，突然你就七英尺高了。

Give yourself an extra couple growth spurts during your teenage years and suddenly you're seven feet tall.

问题是，这个问题约束条件很多，我们在其他阶段有很多数据。

And the problem is it's a fairly over constrained problem that we do have a lot of data at other junctures along the way.

所以，这既要从理论上提出想法，也要从观测上检查是否有问题。

And so it's a wrestle both from the theory to come up with ideas that can do it, and from the observations to find out if there's anything amiss with the observations.

所以这是我一直在纠结的问题。

And so that is one that I've been wrestling with a lot.

我肯定有些听众在想，他们听说过暗能量和暗物质。

I'm sure there are some listeners who are thinking they've heard about dark energy, dark matter.

这些似乎都是大问号。

It seems like these are big question marks.

也许科学家们并不真正知道自己在做什么。

Maybe the scientists don't really know what they're doing.

你知道，他们用了一些词，但只是为了掩盖他们的无知。

You know, they're using words, but it's just to cover up their ignorance.

而且，正如你指出的，在很多方面，还有尘埃。

And also, these as you pointed out, in many ways, there's dust.

这些测量很困难。

There's these measurements are difficult.

这些天体非常遥远。

These objects are very far away.

你知道，如果我要持怀疑态度，你怎么知道整个故事中没有错误，系统性的错误？

You know, if I'm gonna be skeptical, how do you know that there aren't errors in this whole story, systematic errors?

我们知道的最好方法是，首先，我们建立了大量的冗余。

The best way we know is that, first of all, we build in lots of redundancy.

这是我喜欢科学的一点，我可以坐在实验室里，用我的数据做一些计算，然后说，看，有暗能量。

This is the one of the things I love about science is I could sit there in my laboratory with my data and do some calculations and say, behold, there's dark energy.

对吧？

Right?

但我必须发表这些结果，其他人会去验证。

But I have to publish those results and other people check them.

与此同时，地球另一端的某个人可以分析同一批数据，他们可能会得出不同的结论。

Meanwhile, somebody on the other side of the planet can analyze that same pile of data, and they may come to a different conclusion.

如果每个人都得出不同的结论，那我们就没有发现任何东西。

And if everybody's coming to a different conclusion, we haven't discovered anything.

所以，关键是要有独立验证，由世界各地、不同背景的许多人来做，然后我们再用其他望远镜来观测。

And so the important element of independent verification done by many people in all kinds of places over the planet with different backgrounds and whatnot, then we come in with other telescopes.

我之前提到过我们用地面望远镜。

So I've talked about we use ground based telescopes.

哈勃太空望远镜也看到了同样的结果。

We see the same with the Hubble Space Telescope.

詹姆斯·韦伯太空望远镜也看到了同样的结果。

We see the same with the James Webb Space Telescope.

所以，这种高度的冗余和交叉验证，当人们得到不同的答案时，我们也必须追查下去，问为什么他们会得到不同的答案。

And so the sheer redundancy and cross checking in this, when people get an alternative answer, we also have to run that down too and say, why did they get a different answer?

这确实是个非常棘手的问题。

It's a it's a really tough problem.

想想看，这个模型已经这么出色了，而且我们也不能随便乱调，不然会破坏已经正常运行的环节。

Think given how good the model is and also given that we can't just go around adjusting things without wrecking something else that already works.

这可不容易。

It's not easy.

对。

Right.

这就是最大的挑战。

That's that is the big challenge.

不过话虽如此，如果这算是Lambda CDM模型出现裂痕的一个迹象，那之前也有过其他类似的迹象。

However, having said that, if this is a hint of a crack in Lambda CDM, there are have been other hints as well.

所以说这并不是唯一的实验。

So this is not the only experiment.

再比如最近的DESI实验，它测量了整个宇宙中星系的三维位置，跟宇宙微波背景辐射进行了对比，结果暗示暗能量并不像是宇宙常数。

So more recently, are results from the DESI experiment, which is measuring the three-dimensional positions of galaxies over the whole universe, and compared to the cosmic microwave background, suggests that dark energy doesn't look like the cosmological constant.

看起来那里有些变化。

Looks like there's some change going on there.

还有我们测量附近宇宙物质团块程度的方式，根据大爆炸后不久宇宙的样子，我们原本以为它会比现在更团块一些。

There is the way we measure the clumpiness of matter in the nearby universe that, again, based on the way the universe looks shortly after the big bang in the model, we thought it would look clumpier than it does.

但实际上它看起来更平滑。

Instead, it looks smoother.

所以有这些迹象，一方面可能是裂缝，如果有个非常聪明的人最终把它们都拼在一起，可能会改变整个故事。

So there are these hints, which on the one hand could be cracks, and if, you know, a really clever person eventually puts them all together, might change the story.

这些可能就像毛衣上的一根松线，你拉一下可能把毛衣拆了，或者你只是把它拔掉，然后说，好吧。

These could be the loose thread on the sweater that you pull on and might unravel the sweater or you just pluck it off and you're like, okay.

那不是什么大不了的事。

That was not that big a deal.

我觉得我们不知道，但我觉得科学中好玩的事情之一就是其中的冒险和神秘感，这就是过程。

I think we don't know, but I think one of the fun things in science is the adventure and the mystery of it that this is the process.

过去每个把某样东西称为标准模型的人，最终都不得不修正它。

Every everybody in the past who called something a standard model eventually had to revise it.

有道理。

Good point.

我可以给你举历史例子，这两种情况都确实发生过。

I can give you historical examples of where both were the truth in the situation.

但问题是，科学不是历史。

The problem is that science is not history.

你真的得实际去做那些工作。

You You actually have to do the work.

你得做实验。

You have to do the experiments.

你得有批判性思考。

You have to have the critical thoughts.

这才是科学这么好玩的地方。

That's what makes science so much fun.

这确实很有意思，我也很喜欢你刚才说的。

It is really interesting, and I like your comment too.

虽然我确实有点想反驳一下。

Although I'd be tempted to push back.

我是说，没错，科学不是历史，但科学史上确实有些很有意思的例子，有时候只要把模型稍微调整一下就够了。

I mean, yes, science isn't history, but we do have really interesting examples from history of science where sometimes a little tweak to a model was enough.

对。

Yep.

但有时候就需要一个概念上的彻底变革，比如从牛顿的引力模型到爱因斯坦的广义相对论。

And sometimes you needed a conceptual overhaul like Newton's model for gravity to Einstein's general relativity.

你知道吗，史蒂夫，这是我一直以来最喜欢的例子，我就跟可能不太熟悉的听众讲讲。

You know, Steve, that is my favorite example of all time is and I'll just tell for the listeners who may not be familiar.

回到十九世纪，天文学家们的做法就是一丝不苟地追踪行星的位置，然后推算出它们的轨道。

Back in the eighteen hundreds, what astronomers did was they tracked the positions of planets religiously, and they worked out their orbits.

就是说，在十九世纪早期，他们注意到当时已知最外层的那颗行星——天王星——表现得很反常。

And in the early part of the eighteen hundreds, they noticed that the outermost planet they knew at the time Uranus was misbehaving.

它有时候运行得太快，有时候又太慢。

It was traveling too fast, and it was traveling too slow.

科学家们猜测，还有一颗更远的行星，也就是后来的海王星，在牵引着天王星，只是他们看不见它。

And there was a speculation by scientists that there was another planet which became Neptune, that was further out and was pulling on Uranus, that they couldn't see it.

于是他们用纯数学计算出了它的位置，然后用望远镜去寻找，结果真的找到了。

So they calculated with pure math where it should be and then looked for it with a telescope and found it.

对吧？

Okay?

所以那很棒。

So that was great.

所以牛顿的理论没问题。

So Newton's theory was fine.

只是有些东西没被发现而已。

It was just some missing stuff.

后来到了那个世纪后期，轮到水星出问题了，就是最里面的那颗行星。

And then later in the century, Mercury was the one that was misbehaving, the innermost planet.

它沿椭圆轨道运行，但那个轨道的进动或自转速度并不符合预期。

It travels in an elliptical orbit, and that orbit is not supposed to precess or rotate itself at the rate that it was.

大家为此头疼不已。

And people struggled with that.

他们也想出了同样的办法。

They came up with the same idea.

你看，

Oh, look.

肯定是有颗还没发现的行星在作怪。

It's gotta be a missing planet.

这剧情我们以前见过。

We've seen this movie before.

他们曾设想存在一颗叫作“祝融星”的天体，位于水星和太阳之间。

And they imagined a planet called Vulcan that was between Mercury and the sun.

他们去寻找过它。

They looked for it.

但没能找到。

They couldn't find it.

五十年后，爱因斯坦改变了引力理论，并表明在他的引力理论中，水星在广义相对论下会发生进动。

Fifty years later, Einstein changes gravity and shows that Mercury will precess in general relativity in his theory of gravity.

正如你所说，看起来像是一个小小的观测裂缝，或者毛衣上的一根松线，结果却把整件东西都拆散了。

And as you say, what looks like kind of a small little observational crack or, you know, loose thread on the sweater unravels the thing.

所以这就是为什么很难判断。

And so that's why it's hard to tell.

这到底是海王星那种情况，还是广义相对论那种情况？

Is this a Neptune or is this, you know, general relativity?

我真的不知道。

I really don't know.

很好的例子。

Perfect examples.

对。

Yeah.

很高兴你提到天王星和海王星的事，因为你会看到这两种情况。

I'm glad you brought up the Uranus Neptune thing because you see both types of thing.

需要大的概念性改革，或者可能只是缺少了什么，所以并不是什么大问题，我们真的不知道。

Big conceptual overhaul needed or maybe just something's missing and it's So not a big we don't really know.

好的。

Okay.

所以正如你所说，这是一场冒险，这个伟大的事业，科学总是在进步。

So as you say, it's an adventure, this great enterprise who are in science and always progressing.

还有别的东西要来了，南希·格蕾丝·罗曼太空望远镜？

There's something else coming along, the Nancy Grace Roman Space Telescope?

是的。

Yeah.

援军要来了。

The cavalry is coming.

在这种情况下，有很多伟大的天文台，我很兴奋它们即将上线。

In this case, it's many great observatories, which I'm very excited are coming online.

有维拉·鲁宾望远镜，这是地面上最大的全景观测望远镜，非常强大，几个月前刚开始观测。

There's the Vera Rubin telescope, which is the biggest full view telescope that is on the ground, very powerful, just started observing a few months ago.

还有欧洲空间局的欧几里得任务，最近刚刚发射。另外还有NASA计划在九月发射的南希·格雷斯·罗曼太空望远镜，它简直就像是超级加强版的哈勃望远镜。

There is the Euclid, the European Space Agency mission, which recently launched, and then there is the Nancy Grace Roman being launched by NASA in September of this year, which is kind of a Hubble Space Telescope on steroids.

它单次成像能覆盖的视场大约是哈勃的一百倍，而且运行速度也非常快。

It can collect in a single image about a 100 times the field of view of Hubble, and it operates very quickly too.

所以它的收集数据的能力比哈勃快大约一千倍。

So it's going to have a kind of collecting power that's about a thousand times faster than Hubble.

通过这些海量的数据，我们希望能进一步挖掘出关于宇宙近期膨胀历史的更多信息。

And so with this large amount of data, we hope to tease out more information about the recent expansion history of the universe.

看看暗能量是不是在变化，还有我们能获取的其他各种线索。

If dark energy is changing and any other sort of hints we can get.

对。

Yeah.

所以我们会了解到关于系外行星和星系的各种信息，方方面面都有。

So we'll learn things about exoplanets and galaxies, all kinds of things.

但这确实会让我们的数据能力实现质的飞跃。

But this really should be a quantum leap in terms of our data capability.

而且在我从事这个领域的这些年里，数据确实对我们取得这些突破至关重要。

And as long as I've been in this field, data has really been crucial to making the kinds of breakthroughs that we have.

我们能不能以一个情感点来结束？

If we could just close on an emotional point.

我们的节目叫《为什么的乐趣》。

Our show is called the joy of why.

有什么特别让你感到快乐的吗？

Is there something that brings you particular joy?

是数据能告诉你的东西吗？

Is it what data can tell you?

还是说，作为一名物理学家和天体物理学家，你觉得这其中的乐趣在哪里？

Or what's the fun in this for you being a physicist and an astrophysicist?

对我来说，是神秘感，以及解开谜团的潜力。

To me, it's the mystery, and then it's the potential to answer mystery.

你知道吗，我小时候，如果想知道宇宙有多老、它的命运如何，我会觉得你得去问哲学家或拉比。

You know, when I was a kid, if I wanted to know how old is the universe and what's its fate, I would have thought you're gonna ask a philosopher or a rabbi.

我也不清楚。

I don't know.

但这些问题的答案，凡人可给不出来。

But these aren't the kinds of things that mortal people answer.

科学以及我们拥有的这些能力，让我们能够以系统化的方式去探讨那些极其深刻的大问题，并得到真实的答案，这一点真的很了不起。

And the fact that with science and with these capabilities that we could address really profound big questions and do it in a kind of methodical way and get real answers.

没错。

Yes.

我们会得到新的问题，但不会像《银河系漫游指南》里那个著名的数字42那样，一下子给出一个答案。

We end up with new questions, but doesn't all come as one answer like the famous number 42 in Hitchhiker's Guide.

最后它更像是一个谜题，不过我倒挺喜欢这种状态。

It ends up being kind of a riddle, but I like that.

另外让我想到的是伍迪·艾伦的一部老电影，里面有个小男孩，他心情很低落，但他却说宇宙正在膨胀。

The other thing that occurs to me is an old Woody Allen movie where there's a little boy and he's depressed, but he says the universe is expanding.

然后他妈妈问他：这跟你有什么关系？

And the mother says, what is it to you?

布鲁克林可没在膨胀。

Brooklyn's not expanding.

我的问题是，你的父母还健在吗？

My question is something like, are your parents alive?

他们有没有见证你经历这一切，比如宇宙膨胀这些事？

Did they get to witness all of this stuff that happened to you with the expanding universe?

他们见证了一部分。

They got to witness some of it.

我妈妈还在世。

My mom is still around.

她看到我得了诺贝尔奖。

She saw me win the Nobel Prize.

不过，我得说，他们认为这些都是很深刻的事情。

But, I would say that they thought these were profound things.

我小时候，爸爸会带我出去看星星。

When I was a kid, my dad would take me outside, and we'd look up at the stars.

他不是物理学家，但他懂一些东西。

And he was not a physicist, but he knew a few things.

他会说，你看星星的时候，有没有觉得特别神奇，那些光已经旅行了数百万年才到达我们这里。

And he would say, isn't it amazing when you look at the stars that the light has been traveling to us for millions of years?

所以你现在看到的并不是它们现在的样子。

And so what you're seeing is not actually the way they are now.

而是它们数百万年前的样子。

It's the way they were in millions of years ago.

这真的让我很震撼，他还会说，实际上，那些星星可能已经不存在了，但我们几百万年后才会知道。

This just kind of blew my mind, and he would say, in fact, the stars might not even be there anymore, and we won't know about that for millions of years.

就是这种想法，有信息正在向我们传来。

And just this idea, there's information that's traveling to us.

故事在途中已经改变了。

The story's changed along the way.

我们看到的还是那个古老的故事。

We're still seeing this old story.

这怎么可能呢？

How could that be?

我能追上那道光吗？

Could I catch up to that light?

这些想法让我感到深深的敬畏，我想很多人都是这样。

These are profound things that raise a feeling of awe in me and I think a lot of people.

所以，你知道的，回到伍迪·艾伦电影里的那个孩子，我觉得那里其实有两种视角。

And so, you know, back to that kid in the Woody Allen movie, I mean, there's kinda two perspectives there.

对吧？

Right?

那些心怀敬畏、充满好奇心的人，他们真的很棒。

The the people who have awe and are curious and more power to them.

我也是这样的人。

I'm that kind of person too.

然后还有那种人，比如会说‘嘿’的。

And then the people who are like, hey.

布鲁克林可没有在膨胀。

It's not expanding in Brooklyn.

回去工作吧。

Get back to work.

我也理解。

And I get too.

毕竟我们还得吃饭，还得做很多其他事情。

I mean, we still need to eat, and we still need to do a lot of other things.

但对于那些有敬畏之心或好奇心的人，一旦你仰望星空，知道那里有什么，知道那些问题，你就被迷住了。

But to those who have that awe gene or that curious gene, right, you know, once you look up and you know what's out there and you know the questions, you're hooked.

而且，大自然恰好留下了一条爆米花小路让我们去追随，谁不想沿着那条路看看它通向哪里呢？

And, you know, the fact that somehow nature's put out just enough of a popcorn trail for us to follow, who doesn't wanna follow that popcorn trail and see where it leads?

哦，我很喜欢。

Oh, I love it.

非常感谢你跟我们聊天。

Thank you so much for talking to us.

这是当然的。

This is Sure.

真的很棒。

Really great.

非常高兴你能来《生活的乐趣》节目。

A real pleasure to have you on The Joy of Life.

这是我的荣幸。

My pleasure.

也谢谢你问我三十五年前那节课上让我困扰的事情。

And thanks for asking me what bothered me back in that class thirty five years ago.

关于亚当，有一点特别的是他从未停止。

One thing in particular about Adam is that he hasn't stopped.

他并不是得了诺贝尔奖就满足了，然后把问题留给下一代。

It's not as though he won his Nobel Prize, and now he's satisfied, and he leaves it to the next generation.

实际上，我见过很多诺贝尔奖得主都是这样。

And I have seen this with many Nobel Prize winners, actually.

他们在余生中一直保持着那种孩子般的好奇心。

They continue for the rest of their lives to really have that childlike curiosity.

这种好奇心是坚定不移的。

It's unyielding.

你能感受到它。

And you hear it.

它很有感染力。

It's infectious.

这是一个非常鼓舞人心的故事。

It's a very uplifting story.

我认为这几乎是一个科学如何运作的典范例子。

I think it's almost a paradigm example of how science works.

以亚当为例，我们有新的数据进来，这些数据挑战了我们过去的一些想法。

In the case of Adam where we have new data coming in that's challenging some of what we used to think.

我不得不说，在与亚当的这次讨论中，我没有意识到这个Lambda CDM模型竟然这么好。

I have to say in this discussion with Adam, I hadn't realized how good this Lambda CDM model really is.

它非常有韧性，很难改变。

It's very resilient, and it's very hard to change it.

不是说你可以随便动它。

It's not like you can get away with messing with it.

如果你说的强模型是这个意思，那完全正确。

If that's what you mean by a strong model, exactly right.

我就是这个意思。

That's what I mean.

我的意思是，它很僵化。

I mean, it's rigid.

他称之为，我想，过度确定。

He calls it, I think, one point overdetermined.

这也太令人印象深刻了。

And that's also so impressive.

很多时候人们会说，你对宇宙一无所知，因为95%都是暗的。

So a lot of times people will say, Well, you know nothing about the universe because 95% of it is dark.

其中一部分属于暗物质，另一部分属于暗能量，而我们根本不知道这两者到底是什么。

Some of it's in the dark matter and some of it's in the dark energy, and you don't know what either of those things are.

但我觉得大家没意识到的是，这完全是因为观测数据太精确了。

But I think what people don't appreciate, it's only because of how precise the observations are.

正因为我们要进入绝对精确的宇宙学时代，才能通过观察那些空白区域，确定普通物质只占5%。

It's only because we're in an era of absolute precision cosmology that we're able to look at the negative space and determine that actually we're only 5%.

你懂我的意思吧？

You know?

我们只是其中的一小部分。

We're just a little bit.

我们不过是残留的一点痕迹。

We're just a little residue.

这太令人惊叹了。

It's amazing.

这又是一个让人谦卑的想法，对吧？

It's another humbling thought, Right?

那么，作为一粒残渣对另一粒残渣，我要说再见了，感谢Jana分享你的想法。

So as one speck of residue to another, let me sign off and say thank you, Jana, for sharing your thoughts.

我们下次见。

We'll see you next time.

拜拜。

Bye bye.

再见。

Bye.

如果你喜欢《Joy of Why》并且还没有订阅，请在收听的地方点击订阅或关注按钮。

If you're enjoying the Joy of Why and you're not already subscribed, hit the subscribe or follow button wherever you're listening.

你也可以给这个节目留下评论。

You can also leave a review for the show.

这有助于人们找到这个播客。

It helps people find this podcast.

在quantamagazine.org上可以找到文章、新闻通讯、视频等更多内容。

Find articles, newsletters, videos, and more at quantamagazine.org.

《探索的乐趣》是《量子杂志》的一档播客，该杂志是一份编辑独立的出版物，由西蒙斯基金会资助。

The Joy of Why is a podcast from Quanta Magazine, an editorially independent publication supported by the Simons Foundation.

西蒙斯基金会的资助决定不会影响本播客或《量子杂志》中主题、嘉宾或其他编辑决策的选择。

Funding decisions by the Simons Foundation have no influence on the selection of topics, guests, or other editorial decisions in this podcast or in Quanta Magazine.

《探索的乐趣》由PRX制作公司出品。

The Joy of Why is produced by PRX Productions.

制作团队包括凯特琳·福尔斯、杰德·阿卜杜勒·马利克、吉纳维芙·斯邦斯勒和马雷克·雅各布。

The production team is Caitlin Falls, Jade Abdul Malik, Genevieve Sponsler, and Marek Jacob.

PRX制作公司的执行制片人是乔斯林·冈萨雷斯。

The executive producer of PRX Productions is Jocelyn Gonzales.

埃德温·奥乔亚是我们的项目经理。

Edwin Ochoa is our project manager.

来自《量子杂志》的西蒙·弗朗斯和萨米尔·帕特尔提供了编辑指导，并得到了塞缪尔·贝拉斯科、西蒙娜·巴尔和迈克尔·肯扬戈洛的支持。

From Quanta Magazine, Simon France and Samir Patel provided editorial guidance with support from Samuel Velasco, Simone Barr, and Michael Kenyangolo.

萨米尔·帕特尔是《量子杂志》的主编。

Samir Patel is Quanta's editor in chief.

本期节目的封面艺术由Chanel Nibelink创作，我们的标志由Jackie King和Christina Armitage设计。

The episode art is by Chanel Nibelink, and our logo is by Jackie King and Christina Armitage.

特别感谢康奈尔广播工作室的Garth Avery。

Special thanks to Garth Avery at the Cornell Broadcast Studio.

我是主持人Steve Strogatz。

I'm your host, Steve Strogatz.

如果您有任何问题或评论，请发送邮件至quanta@simonsfoundation.org。

If you have any questions or comments, please email us at quanta@simonsfoundation.org.

来自PRX。

From PRX.