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你可能听说过，或者在饼状图里看到过，说我们根本不知道宇宙的95%是由什么构成的。
You might have heard it said or seen in a pie chart that we have no idea what, like, 95% of the universe is made of.
实际情况总是比这复杂一点，但这句话的精神基本上是对的。
It's always a little more complicated than that, but the spirit of that statement is basically true.
我们在宇宙中能观测到的东西，只占必须存在的能量密度的5%。
What we can observe in the universe only accounts for 5% of the energy density that must exist.
剩下的部分，我们能观测到它们的影响，但除此之外还看不见也理解不了，它们由我们所说的暗能量构成，大约占70%，还有暗物质，大约占另外的25%。
The rest, which we observe the effects of but can't otherwise see or understand yet, is made up of what we call dark energy, about 70%, and dark matter, the other 25% or so.
虽然它们共享一个神秘的名字和神秘的本质，但它们是两种不同的东西，解释的是不同的现象。
Even though they share a mysterious name and a mysterious nature, they are two different things, and they explain different phenomena.
但是，想象一下，两个我们都不理解的、关于宇宙如何运作的独立事物，实际上是有联系的，这算牵强吗？
But is it a stretch to imagine that two separate things that we don't understand about how the universe works are actually connected?
欢迎收听Quanta播客，在这里我们探索基础科学和数学的前沿。
Welcome to the Quanta Podcast, where we explore the frontiers of fundamental science and math.
我是Samir Patel，Quanta杂志的主编。
I'm Samir Patel, editor in chief of Quanta Magazine.
过去几年里，宇宙学领域最大的新闻之一，甚至可以说是最大的新闻，就是观测发现暗能量——也就是那种推动宇宙加速膨胀的神秘力量——似乎正在减弱。
One of the biggest, if not the biggest, story in cosmology over the last couple of years was this observation that dark energy, now this is the mysterious force that pushes the universe to expand faster and faster, seems to be weakening.
按理说它应该是恒定的，所以这真是个巨大的意外，影响也很大。
It's supposed to be constant, so this was a big surprise with big implications.
而为了寻找答案，有些人现在又把目光转回了暗物质，以及一种可能的、共享的暗宇宙。
And the search for answers has now led some back to dark matter and the possibility of a sort of shared dark universe.
我们最近在一篇由史蒂夫·纳图斯撰写的文章里探讨了这个想法，标题叫《暗维度可能连接宇宙的两大未知》。
We explored this idea in a recent story called a dark dimension could link two of the universe's great unknowns by Steve Natus.
今天来和我们聊这个话题的，是那篇文章的编辑，也是Quanta新上任的物理学编辑，杰普森。
Here to talk to us about it is the editor of that story and Quanta's new ish physics editor, Jepsen.
欢迎来到节目，凯瑟琳。
Welcome to the show, Kathryn.
终于把你请来了，真是太好了。
It's great to finally have you on.
哦，谢谢。
Oh, thank you.
终于能上节目了，太好了。
It's great to finally be on.
那么，凯瑟琳，这个重大想法是什么？
So, Kathryn, what's the big idea?
一句话概括，就是暗物质和暗能量可能是有关联的。
The one sentence big idea is that possibly dark matter and dark energy could be connected.
但为了提供更多背景，就像你提到的，宇宙中大约95%的物质是我们不了解的。
But to give more context, as you mentioned, about 95% of the universe is made up of stuff that we don't understand.
不过我们对这95%的宇宙还是知道一些事情的，我们把这95%分成两类：暗物质和暗能量。
But we do know some things about this 95% of the universe, and we divide that 95% into two different categories, dark matter, dark energy.
你可以把它们想象成宇宙的油门和刹车。
You can kind of think of them as the gas and the brakes on the universe.
好的。
Okay.
暗能量就是油门。
Dark energy is the gas.
暗能量是推动宇宙随时间加速膨胀的东西。
Dark energy is something that is pushing the universe to expand at an accelerating rate over time.
暗物质则是刹车。
Dark matter is the brakes.
暗物质把东西拉在一起，让它们慢下来。
Dark matter is pulling things together, slowing things down.
我们自认为知道宇宙中暗物质有多少，也自认为知道暗能量的密度。
And we think we know about how much dark matter there is in the universe, and we think we know about the density of dark energy in the universe.
这两样东西看起来好像是不变的。
And these two things seemed like they were not things that changed.
但最近的研究结果显示，宇宙中暗能量的密度可能会随时间减弱。
But recent results have shown us that possibly the density of dark energy in the universe can weaken over time.
对。
Mhmm.
而且也许在宇宙早期，它更强。
And perhaps early on in the universe, it grew stronger.
这就告诉人们，如果其中一样东西可以变化，那么另一样也可能变化，而且它们之间是相互影响的。
And this tells people that if one of these things can change, perhaps the other one can also change, and they're affecting each other.
这就是我们今天要讨论的想法。
This is the idea that we're talking about today.
好的。
Okay.
我们通常在讨论完一个大概念之后，就得开始定义一些东西。
We often, right after we talk about the big idea, end up having to define things.
我们已经开始定义暗物质和暗能量了，但我想我们能不能稍微讲讲它们的起源故事，这样能更好地理解它们。
And we've started to define dark matter and dark energy, but I wonder if we can go a little bit to their origin stories to understand them a little better.
那么，在我们探索宇宙的过程中，暗物质和暗能量的概念是从哪里来的呢？
So where do the ideas of dark matter and dark energy arise in our quest to understand the universe?
那我们先从暗物质说起吧。
So let's start with dark matter.
好的。
Okay.
那就从维拉·鲁宾说起吧。
And start with Vera Rubin.
维拉·鲁宾是一位天文学家。
Vera Rubin was an astronomer.
在二十世纪六十年代，她和另一位天文学家肯特·福特合作，观测附近的仙女座星系。
And in the nineteen sixties, she was working with another astronomer, Kent Ford, and she was observing the nearby Andromeda Galaxy.
对。
Mhmm.
她原本预期在仙女座星系中，中心区域的恒星会比边缘区域的恒星旋转得更快。
One thing she expected to see from the Andromeda Galaxy was that the stars in the center would be rotating around faster than the stars at the edges.
没错。
Right.
这是我们从旋涡星系的视觉上就能预料到的。
Which we would expect from the visual of a spiral galaxy.
看起来中心转得快，外面转得慢一些。
It looks like the center's going faster, and the outside's going a little slower.
嗯，看起来中心的质量最大，因为那里物质最多，我们能看到的星星也最多。
Well, it looks like the center has the most mass because there's the most stuff there, there are the most stars there that we can see light from.
所以想法是，中心的物体应该比边缘的物体更强烈地感受到引力的拉扯。
So the idea is that the things in the center should be feeling the pull of that gravity more strongly than the things at the edges.
对。
Right.
我们在自己的太阳系里也能看到这一点。
And we see this in our own solar system.
离太阳最近的行星比离得远的行星移动得更快。
Planets that are closest to the sun are moving faster than the planets that are farther away.
所以当她观测仙女座星系时，她发现实际上中心和边缘的星星移动速度是一样的。
So when she made this observation of the Andromeda Galaxy, she saw that actually the stars in the center and the stars on the edge were moving at the same rate.
好的。
Okay.
所以那很奇怪。
So that was strange.
对。
Yeah.
她想起在研究生时学到的一个东西，那是天文学家弗里茨·威克提出的一个想法。
And she remembered learning about something in grad school, and this was an idea from an astronomer named Fritz Wicke.
嗯。
Mhmm.
他是个非常聪明的人，提出了很多在当时不被接受的想法。
He's a very smart guy, came up with a lot of ideas that were not always accepted in his time.
好。
Okay.
其中一个想法是，宇宙中存在着某种东西，它有引力，有质量，但我们看不见。
One of them was that there is something out there in the universe that has a gravitational pull, that has mass, that we can't see.
他是在观察后发星系团时提出这个想法的，那是一个由一千多个星系组成的集合，这些星系也在旋转。
He came up with this idea looking at the coma cluster, which is a collection of more than a thousand galaxies that were spinning also.
他发现它们旋转得太快了。
And he saw that they were spinning way too fast.
整个星系团都在旋转吗？
Like, the whole cluster is spinning?
是的。
Yes.
对。
Right.
单个星系在旋转，但星系团本身也在旋转
The individual galaxies are spinning, but the cluster itself spins
也是。
too.
星系团在旋转。
Cluster spins.
好的。
Okay.
它旋转得很快，根据他能看到的星系团中的物质总量，一切本应该飞散开来。
It's spinning fast enough that based on the amount of matter that he could see was in this cluster of galaxies, everything should have just flown apart.
好的。
Okay.
但它没有。
But it didn't.
所以他提出，也许那里还有别的东西，提供了比我们能看到的更多的质量，他称之为暗物质。
So he proposed that maybe there's something else there that is giving us a lot more mass than we can see, and he called it dark matter.
对。
Right.
他的想法是，如果那里有那么多额外的物质，根据我们理解的宇宙规律和引力，就能解释你在那个星系团中看到的行为。
With the idea that if there is that much more matter there, it would by the laws of the universe and gravity that we understand, it would explain the behavior that you see in that cluster.
是的。
Yes.
好。
Okay.
所以有一些看不见的物质。
So there's some invisible matter.
它就在那里。
It's there.
它没有消失，只是看不见。
It's not missing, but it's invisible.
是的。
Yes.
对。
Right.
好。
Okay.
鲁宾记得这件事，然后回去研究了其他旋涡星系，嗯。
And Ruben remembered this and went back and looked at other spiral galaxies Mhmm.
因为她知道需要更多证据，就不断观察一个又一个旋涡星系，结果每次都看到同样的现象。
Because she knew she would need more evidence and just kept observing spiral galaxy after spiral galaxy and kept seeing the same behavior.
好。
Okay.
所以最终，这就是科学家们真正认真对待维兹维基提出的想法所需要的证据。
So finally, this was the evidence that scientists needed to really take seriously the idea that Wizwiki had proposed.
对。
Right.
所以多条观测线索都表明，宇宙中存在着某种我们因为某种原因无法观测到的物质，这就是暗物质。
So multiple lines of observation have suggested that there is some kind of matter that is out there that we can't observe for whatever reason, and this constitutes dark matter.
是的。
Yes.
好。
Okay.
太好了。
Great.
它解释了引力的行为。
It explains the behavior of gravity.
这就是你之前提到的，它就像一种把东西凝聚在一起的力量，因为质量产生引力，把星系拉在一起，并解释了它们的运动行为。
And this is you mentioned earlier, it's like what's holding things together because the mass is leading to gravity that's pulling the galaxies together and explaining their behavior.
是的。
Yes.
好的。
Okay.
所以我们有暗物质。
So we have dark matter.
说得通。
Makes sense.
我们能理解它，也能去寻找它。
We can understand that, and we can look for it.
那暗能量呢？
Now what about dark energy?
好。
K.
说到暗能量，我们先从阿尔伯特·爱因斯坦讲起。
For dark energy, let's start with Albert Einstein.
好的。
Okay.
我们认识他。
We know him.
所以爱因斯坦当时在做他的场方程。
So Einstein was doing his field equations.
他在研究宇宙的几何结构，试图弄清楚时空和物质是如何相互影响的。
He was looking at the geometry of the universe and trying to figure out how space time and matter affected one another.
对。
Mhmm.
然后他意识到，其中一个推论是，引力应该把东西拉在一起，让宇宙收缩。
And he realized that one implication was that gravity should be pulling things together and should be shrinking the universe.
但实际情况似乎并非如此。
But that didn't seem to be happening.
好。
K.
所以他在方程里加了一个东西，叫做宇宙常数。
So he added to his equations this thing he called the cosmological constant.
对。
Right.
这个常数是用来抵消引力，让宇宙保持静止的。
That was meant to counteract gravity and keep the universe static.
好的。
Okay.
听起来有点像数学上的小把戏。
It almost sounds like a little mathematical sleight of hand.
我们觉得一切应该聚拢在一起。
We think everything should be coming together.
但事实并非如此。
It's not.
所以就在里面加个常数，让它保持原样。
So let's just put a constant in there to keep it the way it is.
基本上就是这样。
Basically.
好的。
Okay.
好的。
Okay.
所以它的起源故事有点像是先让数学成立，其他的以后再想。
So its origin story is a little bit of let's just make the math work and then figure out everything else later.
对。
Yeah.
好的。
Okay.
然后到了1929年，埃德温·哈勃在观察遥远恒星的光时，注意到这些光在传到地球的过程中被拉长了。
Then in 1929, Edwin Hubble was looking at the light from distant stars and noticed that it was getting stretched out as it traveled to Earth.
没错。
Right.
这告诉我们宇宙并不是静止的。
And this told us that the universe was not static.
它其实是在膨胀的。
It was actually expanding.
所以我们的常数会变。
So our constant changes.
是的。
Yes.
好。
Okay.
这个常数不再能解决那些方程了。
The constant doesn't fix the equations anymore.
爱因斯坦就把它扔掉了。
Einstein threw it out.
但这让我们想到，也许宇宙是从类似大爆炸这样的东西开始的。
But this gave us the idea that perhaps the universe started from something like the Big Bang.
对。
Right.
就是说宇宙一开始很小，然后在膨胀。
That it started very small, and it was expanding.
而且这种膨胀从大爆炸开始就一直持续着。
And kind of that expansion was just continuing from the Big Bang.
最终，也许它会耗尽能量。
And eventually, maybe it would run out of steam
明白。
Mhmm.
然后慢下来，甚至可能再次收缩。
Would slow down, and perhaps even start contracting again.
引力可能会再次占据主导。
Gravity might take over again.
好的。
Okay.
但到了1998年，有几个独立团队对一种叫做Ia型超新星的爆炸恒星进行了观测，结果发现了一些不同寻常的东西。
But then in 1998, there were a couple of different observations from independent teams of this type of exploding star called a type one a supernova.
Ia型超新星爆炸时亮度是恒定的。
A type one a supernova explodes with a constant brightness.
所以他们把它称为标准烛光。
So they call it a standard candle.
你是说，每一颗Ia型超新星的亮度都完全一样。
You can Every single type one a supernova is the exact same brightness.
对。
Yes.
据我所知是这样的。
As far as I understand.
这难道不奇怪吗？
Isn't that weird?
确实挺奇怪的。
That does seem weird.
对。
Yeah.
但这是真的。
But it's true.
不管它们在哪里，离我们有多远，亮度都是一样的。
Regardless of where they are and how far away they are, it's the same brightness.
是的。
Yeah.
我们知道它们爆炸时的亮度。
We understand the brightness at which they explode.
好。
Okay.
所以我们可以利用这一点，就像你看汽车的前灯，你能看出它们看起来有多大，从而判断汽车似乎有多远。
And so we can use that kind of like if you're looking at headlights from a car, you can see how big they seem and that you can see how far away the car seems to be.
没错。
Right.
这就把变量从方程里剔除了，因为我们知道它的亮度是恒定的，所以我们可以对这些特定的恒星提出其他问题。
It takes a variable out of the equation because we know it's a constant brightness so we can ask other questions of these particular stars.
所以我们有这些关于Ia型超新星的观测数据，嗯。
So we have these observations of type one a supernovas Mhmm.
然后发现宇宙确实在膨胀，但实际上是在加速膨胀。
And see that the universe is indeed expanding, but it's actually expanding at an accelerating rate.
好的。
Okay.
它越来越快。
It's getting faster.
不只是膨胀，而是所有东西都在以越来越快的速度彼此远离。
Not just expanding, but, like, everything is zooming apart from everything else increasingly faster.
对。
Yes.
好的。
Okay.
所以这和爱因斯坦最初的想法差得很远，他当时认为宇宙是静止的。
So this is a long way from what Einstein kinda started with, which is just like the universe is static.
我们需要那个小小的数学修正系数来维持这个状态。
We need our little mathematical fudge factor to keep it there.
现在我们发现宇宙在膨胀，而且不仅仅是膨胀。
Now we're at the it's expanding, and not just expanding.
它在膨胀，而且速度越来越快。
It's expanding, but faster and faster.
对。
Yes.
好的。
Alright.
所以这不仅仅是宇宙大爆炸的余波，而是宇宙中有什么东西在推动膨胀加速。
So it's not just that, okay, this is still an effect of the big bang, but there's something in the universe that is causing this expansion to happen and get faster.
没错。
Right.
我们可以直观地理解这一点。
And we can sort of think of this intuitively.
对吧？
Right?
就像爆炸一样。
Like, explodes.
对吧？
Right?
你会想象那些向外飞散的东西，因为重力和其他的力，会减速，甚至可能会回来。
You would imagine that the things that are going out, because, honestly, of gravity and other forces, it would slow, might might come back.
但如果要一直运动下去，就需要另一个能量来源。
But you would need another source of energy if it was to just keep moving.
是的。
Yeah.
明白了。
Got it.
好的。
Okay.
所以我们需要另一种能量来源。
So we need another source of energy.
这个想法是，暗能量的能量密度是恒定的，对吧。
And the idea is that the density the energy density of dark energy is constant Okay.
在宇宙中。
In the universe.
所以随着宇宙变大，这个密度必须保持不变，所以暗能量必须更多。
So as the universe gets bigger, that density has to stay the same, so there has to be more dark energy.
所以暗能量不断增长，推动宇宙越来越快地膨胀。
So dark energy just keeps growing and pushing faster and faster.
我们知道，由于某些原因，能量密度，也就是每块时空区域中暗能量的数量，需要保持不变。
We know for reasons that the energy density so the amount of dark energy per a section of space time needs to stay the same.
所以如果宇宙以不断加速的速度膨胀，我们就需要越来越多的暗能量。
So if the universe is expanding at an ever expanding rate, we need more dark energy all the time.
是的。
Yes.
所以这就是为什么它一直在加速。
And that's why it keeps getting faster.
对。
Right.
或者说，这是目前的想法。
Or that has been the idea.
好的。
Okay.
这说明了暗物质和暗能量之间的一个区别，也就是说，对于暗物质，我们大致知道那里有东西。
This points to something that is distinct between dark matter and dark energy, which is to say, dark matter, we know, more or less, something is there.
只是我们暂时还看不见它。
We just can't see it yet.
暗能量感觉就像是另一个层次的谜团。
Dark energy feels like it's on another level of mystery.
这个分类听起来合理吗？
Does that sound like a good categorization?
暗物质就像我们在找某种看不见的东西。
It's almost like dark matter is we're looking for something that that is invisible.
而暗能量，我们只是在试图搞清楚到底发生了什么。
Dark energy, we're just trying to figure out what the hell is going on.
对。
Yeah.
听起来差不多是这样。
That sounds about right.
好的。
Okay.
好的。
Okay.
芝加哥大学的迈克尔·特纳提出了“暗能量”这个术语。
Michael Turner at the University of Chicago came up with the term dark energy.
他提出这个术语的时候，是想参照暗物质，把它们联系起来。
And when he came up with that term, he was trying to reference dark matter to kind of tie them together Okay.
因为他希望科学家们把这两个谜团看作同等重要。
Because he wanted scientists to think of these two mysteries as kind of equally important.
这些都是我们亟待解决的重大谜团。
These are big, big mysteries that we need to solve.
不过，它们确实是完全不同的东西。
But, yeah, they're very different types of thing.
一个叫暗，是因为我们看不见它。
One is dark because we can't see it.
另一个叫暗，是因为我们还不理解它。
The other one is dark because we don't understand it yet.
但你是说，暗能量这个术语最初就是为了把它们联系起来，即使我们目前还没有办法真正把它们关联起来。
But you're saying that the original genesis of the term dark energy was meant to relate them in some way even if we don't necessarily yet have a way to relate them.
是的。
Yes.
除了一个让东西膨胀，一个让东西收缩之外。
Outside of the fact that one makes things expand, and one makes things contract.
这就是你说的油门和刹车的类比。
This is your gas and break analogy.
对。
Right.
好。
Okay.
我们之前提到过，最近有一些发现，比如说，暗能量并不像数学和其他观测所认为的那样恒定，它似乎在变弱，这可能意味着我们看到的宇宙膨胀加速可能正在减缓。
We mentioned earlier that there's some recent findings, let's say, that dark energy is not as constant as the math and other observations would have us believe, that it seems to be getting weaker, which would suggest that we're seeing the acceleration of the expansion of the universe potentially slowing down
是的。
Yes.
最终的结果可能是它完全停止膨胀，然后也许一切慢慢重新聚拢的想法是有可能的。
With an eventual outcome that maybe it stops expanding entirely, and then maybe this idea of everything kind of slowly coming back together is possible.
是的。
Yes.
好的。
Okay.
宇宙的另一种结局是热寂。
Which the alternative end of the universe is like the heat death of the universe.
万物永远膨胀，然后我们就变成一堆粒子，时间也不存在了。
Everything expands forever, and then we just we are a soup of particles, and time no longer exists.
对。
Yep.
好的。
Okay.
所以这个发现，暗能量可能正在减弱，这就像暗能量还不够神秘似的。
So this finding that dark energy might be weakening is one of these things that's like as if dark energy wasn't mysterious enough.
现在又有了一个新的谜团，这让我们开始寻找答案。
Now we have another mystery, which which sends us kind of looking for answers.
他们是怎么发现这一点的？
How did they find that out?
这是暗能量光谱仪的一个重大成果。
This was a big result from the dark energy spectroscopic instrument Okay.
在2024年。
In 2024.
一个专门用来观测和研究暗能量的仪器。
A purpose built instrument to observe and try to figure out dark energy.
是的。
Yes.
好的。
Okay.
它有很多小型的机器人眼睛，可以快速移动，设计用来观测数百万个不同距离的星系，绘制一张宇宙的大地图。
It has all these little robotic eyes that can move very quickly, and it's designed to look at millions of galaxies at different distances from us and make a big map of the universe Mhmm.
然后利用这张地图来了解宇宙的膨胀是如何随时间变化的。
And use that map to figure out how is the expansion of the universe changing over time.
所以我们原本以为宇宙膨胀是在以稳定的速度加速。
So we thought that it was accelerating at this steady rate.
对。
Right.
但在2024年，DESI根据对640万个星系的观测发布了一项结果。
But in 2024, DESE put out a result based on observations of 6,400,000 galaxies.
好。
K.
并且首次有了一些相当令人信服的迹象，表明这种膨胀正在发生变化，实际上正在随时间减弱。
And for the first time, had some pretty convincing hints that this expansion was changing, that it was actually getting weaker over time.
好的。
Okay.
因为大概来说，物体离我们越远，我们观测到的它就越早，因为一切都在相互远离。
Because presumably, the further away an object is, the further back in time our observations of it are because everything is moving apart.
所以他们基本上可以通过观测不同距离的物体来看到不同的时间点。
So they're able to basically look at different times by looking at objects that are at different distances from us.
是的。
Yes.
对。
Right.
他们还观察到这些不同距离的光被拉伸的程度。
They're also seeing things like how stretched the light is from these different Right.
不同距离的物体。
Objects at different distances.
好的。
Okay.
所以数据很多，但还不是非常确凿的观测结果。
So lots of data, but not a very firm observation yet.
已经足够令人兴奋了。
Convincing enough to be very exciting.
是的。
Yes.
然后去年，DESE增加了更多的观测，基于三年的数据和1500万个星系，获得了更多数据。
And then last year, DESE added more observations, more data based on three years of data and 15,000,000 galaxies.
好。
K.
所以更好了。
So better.
他们一直看到同样的结果。
They kept seeing the same thing.
我们在《Quanta》上报道了这两项发现。
We reported on both of these findings in Quanta.
统计显著性提高了，但至少到目前为止，还没有完全达到粒子物理学中“发现”的标准。
The statistical significance of this has gone up, but it hasn't quite reached the level of a discovery in particle physics at least so far.
所以人们对此很兴奋。
So people are excited about it.
随着更多观测和不同实验的进行，这个结果仍有可能减弱或消失，但人们还是很兴奋。
There's still the possibility with more observations and different experiments looking at this that it could weaken or go away, but people are excited.
是的。
Yes.
好的。
Okay.
我还知道，宇宙膨胀还有一个复杂的问题，就是所谓的哈勃张力，这和暗能量可能减弱不是一回事，但感觉也不是完全无关。
I do also know that there's one other complication with the expansion of the universe, which is what they call the Hubble tension, which is not the same as talking about the potential weakening of dark energy, but it's feels like it's not unrelated.
那你能解释一下什么是哈勃张力吗？
So can you explain what the Hubble tension is?
哈勃张力是指对同一事物的两种不同测量结果之间的矛盾。
The Hubble tension is a tension between two different types of measurements of the same thing.
这是对哈勃常数的两种测量。
It's two measurements of the Hubble constant.
如果宇宙膨胀的速度是恒定的，那么更远、更古老、膨胀时间更长的星系，看起来应该会以更快的速度远离我们。
If the rate at which the universe is expanding is constant, then galaxies that are farther away and older and have been at it longer should appear to be moving away from us faster.
这正是埃德温·哈勃在二十世纪二十年代观察到的现象。
And that's exactly what Edwin Hubble observed in the nineteen twenties.
所以哈勃常数衡量的就是宇宙的稳定指数膨胀。
So that's what the Hubble constant measures, the steady exponential expansion of the universe.
还有利用早期宇宙的光来测量哈勃常数的方法。
And there are measurements of the Hubble constant that use light from the early universe.
嗯。
Mhmm.
这些测量来自宇宙微波背景辐射。
These are measurements from the cosmic microwave background.
这就像是我们拥有的宇宙的婴儿照片，是第一批能够逃逸出来的光。
This is kind of the baby picture of the universe that we have with the first light that was able to escape.
嗯。
Mhmm.
基于这个的测量也有。
There are measurements of it based on that.
这告诉我们早期宇宙膨胀的速度有多快。
That tells us how fast the universe was expanding in the early universe.
对。
Yeah.
然后我们还有基于更近期现象的测量，比如超新星。
Then we have measurements based on more recent phenomena like supernovas.
那些更近一些。
That are much closer.
对。
Yes.
所以我们可以从中看出宇宙最近是如何膨胀的。
So we can tell from that how the universe is expanding more recently.
好的。
Okay.
如果哈勃常数是一个常数，那么这些测量应该给出相同的数值。
If the Hubble constant is a constant, then those measurements should give us the same number.
没错。
Right.
但科学家们用各种方法测量了这两者，结果相当一致地发现它们并不相等。
But scientists have measured both in a variety of ways, and they have pretty consistently found that the two are not equal.
这两种测量结果之间大约有9%的差异。
There's about a 9% difference between the two types of measurements.
好的。
Okay.
这可能意味着我们的测量方法有些问题，也可能意味着还有其他因素在起作用。
This could suggest that there's something not quite right about the way we're making these measurements, or it could mean that there's something else going on.
真是谜团重重啊。
So mysteries on mysteries.
但我注意到，我们之前讨论的暗物质和暗能量，它们似乎确实是在完全不同的尺度上运作的。
But one thing I see here is that the dark matter we were talking about and dark energy, they really seem to be operating on entirely different scales.
比如，我们考虑暗物质时，是从单个星系的角度出发的。
Like, the individual galaxy scale is how we're thinking about dark matter.
不过，它确实也影响了宇宙的整体结构。
Although, it does impact the overall structure of the universe.
宇宙中有数万亿个星系。
There are trillions of galaxies.
而暗能量则像是整个宇宙本身，无处不在，无时不在。
And then dark energy is like the entire universe itself everywhere all the time.
所以我们回到这个想法，它们可能是有联系的。
So let's go back to this idea that they potentially could be connected.
因为我们重新审视之前提出的那个想法，用新的视角来看待暗能量运行方式中出现的一些问题。
Because we're going back to an idea that had previously been raised in order to look with fresh eyes at some of the problems that are coming up with the way specifically dark energy seems to operate.
所以有一篇2005年的论文，史蒂夫在文章中提到过，科学家们试图解释一个暗能量可能随时间变化的宇宙。
So there's this 2005 paper that Steve mentioned in the article in which scientists were trying to come up with an explanation for a universe in which dark energy could change over time.
好。
K.
那怎么用物理定律来解释呢？
How could we square that with the laws of physics?
所以在2005年，有
So in 2005, there was
在DESI结果出来之前，
before the DESI result, by the
是的。
way Yes.
2005年。
In 2005.
所以那时候他们只是在猜测暗能量会变化。
So they're just they're just guessing about dark energy changing at that point.
当时还没有任何观测表明它可能会变化。
There had been no observation that it might be changing.
没有。
No.
好的。
And Okay.
而且从一开始，他们就已经开始考虑这个问题了。
Even from the beginning, they had started thinking about this.
所以
So
那要是呢？
So what if?
对。
Yes.
是的。
Yeah.
好。
Okay.
要是它变了呢？
What if it changed?
史蒂夫提到的2005年那篇论文，就是研究怎么解释这个现象的。
This paper that Steve mentioned in 2005 looked at how could we explain that.
那篇论文实际上提出，暗能量和暗物质之间可能存在某种联系，这种联系会让暗能量的能量密度看起来随时间变化。
It actually explained that dark energy and dark matter could be connected to each other in a way that would make it look like the energy density of dark energy was changing over time.
所以DESE结果出来后，理论物理学家们就赶紧想办法提出各种理论，来解释这种情况是怎么发生的，又是怎么运作的。
So after the DESE result came out, theorists were scrambling to try to propose theories to explain how this might have happened, how this might work.
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一月份有一篇论文发表，解释说暗物质和暗能量可能是相互关联的，暗物质可能把一部分能量给了暗能量。
In January, there was a paper that came out that explained that perhaps dark matter and dark energy are connected, and dark matter could have given some of its energy to dark energy.
就像我之前说的，暗物质就像刹车。
And as I mentioned, the dark matter is the brakes.
暗能量就像油门。
Dark energy is the gas.
如果你把一部分给刹车的能量转给油门，那就能解释宇宙早期暗能量开始加速膨胀的现象。
If you take some of the energy going towards the brakes and give it to the gas, then that could explain early on in the history of the universe when dark energy started speeding up.
这里的建议是，暗物质的某种变化可能导致了暗能量的变化。
The suggestion here is that some change in dark matter might have been what has allowed dark energy to change.
这是否意味着，如果暗能量实际上在减弱，我们观察到的暗物质的影响在某种程度上在增强？
Does that suggest now that the impact we observe from dark matter, if dark energy is actually weakening, is somehow increasing?
这可能意味着人们有不同的理论。
It could suggest that there are different theories that people have.
史蒂夫在文章中提到了一些弦理论学家讨论过这个问题。
Steve mentions in the article some string theorists who talked about this.
弦理论，我们之前在播客里聊过。
String theory, we've talked about in this podcast before.
它确实能让人脑子转不过弯来。
It can definitely twist you up mentally.
理解起来挺费劲的。
It is a challenging thing to understand.
对。
Yes.
我觉得真正奇怪的是，我们讨论的是宇宙尺度，早期宇宙。
The thing that I think is actually weird about this is we're talking about cosmic scales, the early universe.
我们说的是星系。
We're talking about galaxies.
而弦理论是亚原子层面的。
String theory is subatomic.
对吧？
Right?
就像是最微小的东西。
It's like the very smallest things.
弦理论怎么可能和我们能理解的暗物质、暗能量这个概念联系起来呢？
How could string theory possibly be connected to this idea of dark matter and dark energy in a way that we can understand?
弦理论家认为，在基本层面上，物质不是由粒子或场构成的。
So string theorists posit that at the fundamental level, things are not made up of particles or fields.
它们是由微小的振动弦组成的。
They're made up of tiny vibrating strings.
而且弦理论要求宇宙，为了让这个理论成立，
And string theory requires the universe, for this to make sense
对。
Yeah.
必须有额外的六七个维度。
To have an extra six or seven dimensions.
这些维度都是卷曲起来的。
That are all folded up.
它们都很小。
They're all tiny.
卷曲在微小的亚原子空间里。
Into tiny subatomic spaces.
回去听听我们和娜塔莉做的那期关于弦理论的节目。
Go back and listen to the episode we did with Natalie about string theory.
那很复杂。
It's complicated.
不过没关系。
It's fine.
对吧？
Right?
它只是一个理论。
It's a theory.
人们对它有着非常强烈的看法。
People have very strong feelings about it.
但它确实有解释力，而且对科学家来说仍然很有趣。
But it does have explanatory power, and it is still interesting to scientists.
但正如你所说，它确实需要存在六个看不见的卷曲维度。
But as you say, it does require there to be six invisible folded up dimensions
或者七个。
Or seven.
除了我们熟悉的四个维度之外，还有六个或七个看不见的卷曲维度。
Six or seven invisible folded up dimensions in addition to the four that we're familiar with.
是的。
Yes.
明白了。
Got it.
而这个结果的联系在于，其中一个维度可能比其他维度更大，尽管它仍然非常小。
And the connection with this result is that one of those dimensions could be bigger than the other ones even though it's still very small.
好。
K.
而且它可能是一个暗维度。
And it could be a dark dimension.
说实话，我张开嘴想说点什么，但脑子里一片空白。
Honestly, I opened my mouth to say something, and I had nothing.
暗维度。
Dark dimension.
可能有一个暗维度。
There could be a dark dimension.
好的。
Okay.
史蒂夫在文章里提到的那些论文中，有些观点认为暗物质和暗能量可能都在这个暗维度中相互作用。
And the idea from some of these papers that Steve mentions in the article is that dark matter and dark energy could both interact in this dark dimension.
如果暗维度发生变化，那么暗物质和暗能量都可能随之改变。
And if the dark dimension changed, then that could change both dark matter and dark energy.
对。
Right.
这我真的知道，因为我们之前聊过弦理论。
Which really I I know because we've talked about string theory before.
它有一种数学上的优雅，能把很多东西联系起来，这也是为什么人们仍然觉得它有趣。
It has this kind of mathematical elegance that connects things, which is why people still think it's interesting.
这听起来就像是那种情况：我们有所有这些重大的宇宙学发现，然后弦理论在旁边说，嘿。
And this sounds like one of those cases where we have all of these big cosmological findings, and then you get string theory off to the side going, hey.
顺便说一下，我可以解释这个。
I can explain that, by the way.
我有一个非常优雅的公式，可以解释其中一些。
I I have a very elegant formula that would explain some of this.
然后宇宙学家说，哦，那你怎么验证呢？
And then the cosmologist said, oh, well, how would you test that?
弦理论就说，我不知道。
And string theory is like, I don't know.
别问我。
Don't ask me.
我就是弦理论。
I'm string theory.
不过这一次，他们确实有一种方法可以大致验证一下。
Well, this one, they did have one way to kind of test it.
我不是说弦理论给出了一个可验证的预测。
I'm not saying that there was a testable prediction from string theory.
还没那么强。
It's not quite that strong.
对。
Right.
但是弦理论家们一直说，弦理论很难预测一个暗能量是恒定的宇宙。
But string theorists have been saying for a while now that it's really hard for string theory to predict a universe in which dark energy is constant.
好。
Okay.
他们很难用数学来模拟出我们宇宙加速膨胀的情况。
It's hard for them to do the math that makes our universe expand at an accelerating rate.
这是那些能让弦理论稍微打开一扇门的小事之一，就像在说，非弦理论，你觉得你把一切都搞清楚了吗？
This is one of those little things that, like, creaks the door open for string theory a little bit where it's like, non string theory, do you think you have everything figured out?
你看。
Look.
你有一个说不通的发现。
You have a finding that doesn't make any sense.
我们为这个困扰了很久。
We've been struggling with that for ages.
对。
Yeah.
是的。
Yeah.
好。
Okay.
所以DESI的结果其实对弦理论家来说是个礼物，因为他们从2018年那篇论文开始就一直说，弦理论更容易描述一个暗能量是变化的宇宙。
So the DESI result was actually kind of a gift to string theorists because string theorists have been saying since this 2018 paper that it's a lot easier for string theory to describe a universe in which dark energy is variable.
对。
Right.
好。
Okay.
所以如果它是可变的，那么
So if it is variable, then
而且很可能就是可变的。
And it might very well be.
那可能会让事情变得更容易，对吧。
That might make things easier Right.
对弦理论来说。
For string theory.
然后它就有了这条路，这个暗维度。
Then and then it has this path, this dark dimension
是的。
Yes.
这会与暗物质联系起来，用来解释变化的暗能量。
That would connect with dark matter to explain a variable dark energy.
是的。
Yes.
其中一篇论文解释的是，如果存在这个暗维度，那么暗物质之间的引力可能比暗物质与普通物质之间的引力更强。
And one thing that one of these papers explains is that if there's this dark dimension, it could be that dark matter is more strongly attracted to other dark matter than it is to regular matter.
好的。
Okay.
这是你实际上可以观察到证据的事情。
And that's something that you could actually observe evidence of.
如果有两个星系相互经过，暗物质和普通物质的引力以不同的强度向不同方向作用。
If there were two galaxies that passed by each other and the gravity from the dark matter and the regular matter were pulling in different ways with different strengths.
对。
Right.
那么当一个经过另一个时，应该会有一种叫做潮汐尾的东西拖在后面。
Then as one passed by the other, there should be this thing called a tidal tail that trails behind it.
对。
Right.
所以这是你可以观察到的东西。有人确实去找过潮汐尾，虽然不是针对这个理论，但并没有真正找到。
And so that is something that you could see someone actually had gone and looked for tidal tails, not related to this, and hadn't really found them.
好的。
Okay.
但是宇宙中有很多很多星系，要形成这种现象需要非常特定的条件。
But there are lots and lots of galaxies out there, and you need a very specific set of circumstances for that to form.
而且他们并没有排除这种可能性。
And they didn't rule it out.
好的。
Okay.
所以这就是弦理论家指出的结果，是的，人们已经能够去寻找这个现象，而且他们……对。
So that is the result that string theorists were pointing to that, yes, people have already been able to look for this, and they Right.
并没有排除它。
Haven't ruled it out.
所以这里的想法是，当我们总结时，我们要转向一个大想法，那就是宇宙有两大谜团。
So the idea here and then we're turning to the big idea as we wrap this up, is we have these two great mysteries of the universe.
暗物质本身似乎并没有变得更神秘。
Dark matter doesn't feel like it's getting more mysterious exactly on its own.
但至少其中一个，我们越试图了解它，它就变得越神秘。
At least one of them gets more mysterious the more we try to learn about it.
它有一些不一致之处，我们还不确定该如何解释，而且似乎有几个理论框架，包括弦理论，暗示一种解释方式是这两者实际上是相连的。
It has these inconsistencies associated with it that we're not sure what to make of yet, and seems to be a couple of theoretical frameworks, including string theory, that would suggest one way to explain this is if the two are actually connected.
所以即使它们描述的是不同的现象，它们仍然是同一辆车的部件。
So even though they're describing different phenomena, they are still parts of the same car.
你之前提到了油门和刹车。
You said gas and brakes earlier.
它们仍然是同一个系统的一部分。
They're still parts of the same system.
对。
Mhmm.
好的。
Okay.
我觉得我们真的说到点子上了。
I think we actually got to it.
我觉得这对我来说很有道理。
I think that makes sense to me.
哦，太好了。
Oh, great.
太棒了。
Amazing.
我建议大家去看看史蒂夫的文章。
I recommend that everyone go and check out Steve's article.
另外，也去看看《量子》杂志对Desi发现的报道，还有我们最近关于弦理论的《Qualia》专栏，因为这是那种有很多小线索的故事，这些线索和我们一直在报道的其他内容都有联系。
Also, check out the other Quanta coverage of the Desi findings, our recent Qualia column on string theory, because this is one of those stories that has these little threads that kind of connect to all this other stuff that we've been covering.
所以看到这个真的很满意，而且标题也很有意思。
So I was really satisfied to see it, and the headline is very intriguing.
谢谢你给我们讲这些，凯瑟琳。
And thank you for presenting all of this to us, Kathryn.
没问题。
Sure.
谢谢你们邀请我。
Thanks for having me on.
在结束之前，我们总是喜欢请嘉宾推荐点什么。
Before we let you go, we always like to ask our guests for a recommendation.
那你最近对什么特别感兴趣？
So what's been exciting your imagination lately?
我最近读了一本非虚构类的书，叫《真实的颜色：从天蓝到锌粉，定义颜色的奇妙之旅》，作者是科里·斯坦珀。
I recently read a nonfiction book called True Color, The Strange and Spectacular Quest to Define Color from Azure to Zinc Pink by Corey Stamper.
好的。
Okay.
我觉得这本书很棒。
And thought it was great.
这本书的作者曾在梅里亚姆-韦伯斯特词典公司担任编辑。
This is by a writer who worked for Merriam Webster as an editor.
她在工作中注意到，梅里亚姆-韦伯斯特词典第三版里对颜色的描述非常生动有趣。
And one of the things that she noticed in her work was that the third edition of Merriam Webster had these very colorful descriptions of color.
好的。
Okay.
她很好奇，为什么在韦伯斯特词典第三版中，这些颜色描述会变得这么有意思，而其他很多定义却显得比较平淡。
And she wondered how the descriptions got so interesting in this third edition of Webster's where a lot of the other definitions were a lot more A little drier?
是的。
Yeah.
对。
Yeah.
所以这本书带着读者跟随她一起去探寻这些定义的来源，从中你可以了解到美国文化的变化、我们对颜色认知的变化，以及词典编纂方式随时间的演变。
So the book takes the reader on her journey to discover the origin of these definitions, and you learn a lot about changes to American culture, changes to our perception of color, changes to how dictionaries are made over time.
明白。
Mhmm.
所以这真的是一段非常迷人的旅程。
So it's it's just a very fascinating ride.
而且科里·萨米尔的声音很好听，人也很有趣。
And Cory Samir has a lovely voice and is very funny.
其实这本书在我的书单上，我就喜欢这种书，从一个有点奇怪的小细节开始。
I actually I have this book on my list, and it's the kind of book I love where you find this little nugget of something a little weird.
一旦你开始深挖，它就像扩展成一场文化层面的探索。
And once you start digging into it, it, like, expands into this culture wide exploration.
所以，是的，我也很期待读它。
So, yeah, I'm looking forward to reading it too.
很好。
Very nice.
谢谢，凯瑟琳。
Thanks, Kathryn.
另外，本周《量子》杂志上，你可以读到我们关于数学界最高奖项——菲尔兹奖和阿巴克斯奖的全面报道，包括所有获奖者的详细简介以及他们获奖的工作。
Also on Quanta this week, you can read our full coverage of the biggest awards in mathematics, the Fields Medals and the Abacus Medal, with detailed profiles of all the winners and the work that won them recognition.
如果你一直在收听《Quanta》播客，请花点时间给节目评分并留下评论。
If you've been enjoying the Quanta Podcast, please take a moment to rate the show and leave a review.
我们很期待听到你的反馈。
We'd love to hear from you.
《Quanta》播客是《Quanta》杂志旗下的播客，这是一份由西蒙斯基金会支持的独立编辑出版物。
The Quanta Podcast is a podcast from Quanta Magazine, an editorially independent publication supported by the Simons Foundation.
我是《Quanta》的主编，萨米尔·帕特尔。
I'm Quanta's editor in chief, Samir Patel.
西蒙斯基金会的资助决策不会影响本播客或《Quanta》杂志的选题、嘉宾或其他编辑决策。
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.
《Quanta》播客是与PRX制作公司合作制作的。
The Quanta Podcast is produced in partnership with PRX Productions.
制作团队包括阿里·巴德纳、黛博拉·J.
The production team is Ali Budner, Deborah J.
巴尔萨泽、吉纳维芙·斯邦斯勒和汤米·巴扎里安。
Balthazar, Genevieve Sponsler, and Tommy Bazarian.
PRX Productions的执行制片人是乔斯琳·冈萨雷斯。
The executive producer of PRX Productions is Jocelyn Gonzales.
来自《量子杂志》的西蒙·弗朗斯和我负责编辑指导，还有塞缪尔·贝拉斯科、西蒙娜·巴尔和迈克尔·卡南戈洛提供支持。
From Quanta Magazine, Simon France and myself provide editorial guidance, with support from Samuel Velasco, Simone Barr, and Michael Canangolo.
我们的主题音乐来自APM Music。
Our theme music is from APM Music.
如果你有任何问题或意见，请发邮件到quantasimonsfoundation.org。
If you have any questions or comments for us, please email us at quantasimonsfoundation dot org.
感谢收听。
Thanks for listening.
来自PRX。
From PRX.
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