Will We Ever Find Alien Civilizations?

Does intelligent life exist elsewhere in the universe?

宇宙其他地方是否存在智慧生命？

The question has captivated us for centuries, but despite decades of searching it remains frustratingly unanswered.

这个问题几个世纪以来一直困扰着我们，但尽管经过数十年的探索，它仍然令人沮丧地没有答案。

Every so often a curious signal appears — fossilized structures in a meteorite, say, or an unusual gas in an exoplanet’s atmosphere — and for a moment it seems possible that we are not alone before the excitement gives way to a more mundane explanation.

每隔一段时间就会出现一个奇怪的信号——比如陨石中的化石结构，或者系外行星大气中的一种不寻常的气体——在兴奋被更平凡的解释取代之前，我们似乎并不孤单。

So what would it actually take to find life in the cosmos — and how would we know when we saw it?

那么，要在宇宙中找到生命实际上需要什么——我们如何知道何时看到它呢？

David Kipping , an astronomer at Columbia University, has spent his career finding better ways to answer these questions.

哥伦比亚大学的天文学家大卫·基平（David Kipping）在其职业生涯中一直在寻找更好的方法来回答这些问题。

His approach is statistical: rather than chasing individual detections, he develops mathematical frameworks for reasoning about where habitable worlds are likely to exist and how confidently we can interpret the signals they produce.

他的方法是统计性的：他不是追逐个体检测，而是开发了数学框架来推理宜居世界可能存在的位置以及我们如何自信地解释它们产生的信号。

In this episode of The Joy of Why , Kipping joins co-host Janna Levin to discuss efforts to frame one of humanity’s oldest existential questions as a tractable scientific problem, why biosignatures have proved so difficult to interpret, and why he believes exomoons may be an overlooked place to search for life.

在这一集《为什么的喜悦》中，基平与联合主持人詹娜·莱文 (Janna Levin) 一起讨论了将人类最古老的存在问题之一框定为易于处理的科学问题的努力、为什么生物特征被证明如此难以解释，以及为什么他认为外卫星可能是一个被忽视的寻找生命的地方。

Listen on Apple Podcasts , Spotify , TuneIn or your favorite podcasting app, or you can stream it from Quanta .

在 Apple 播客、Spotify、TuneIn 或您最喜爱的播客应用程序上收听，或者您也可以从 Quanta 进行流式传输。

So I spoke to someone who studies deeply the mathematical underpinnings of making these kinds of assessments, and that is David Kipping, who is a colleague of mine.

因此，我与一位深入研究进行此类评估的数学基础的人进行了交谈，他就是我的同事大卫·基平（David Kipping）。

David is an astronomer at Columbia University, where he studies exoplanets and exomoons, and he’s really focused on developing new statistical methods in particular to detect potentially habitable worlds, which I think is a very intriguing way to get ultimately to the question that I think haunts him, which is, are we alone?

大卫是哥伦比亚大学的天文学家，他在那里研究系外行星和系外卫星，他真正专注于开发新的统计方法，特别是探测潜在的宜居世界，我认为这是一种非常有趣的方式，可以最终解决我认为困扰他的问题，即我们是孤独的吗？

And, there was a group in San Diego called the Cool Stars Group, and there’s a big conference called Cool Stars.

而且，圣地亚哥有一个名为 Cool Stars Group 的团体，还有一个名为 Cool Stars 的大型会议。

So Cool Stars, obviously, focusing on these M dwarf stars, these low-mass stars, which it’s really easy to detect planets around them.

显然，Cool Stars 专注于这些 M 型矮星，这些低质量恒星，很容易探测到它们周围的行星。

There’s a lot of interest astrobiologically around these sorts of stars.

天体生物学对这类恒星有很多兴趣。

So there was a huge amount of interest about those, and I thought, “Hey, by extension, it’s the cooler worlds that we also care about.” It’s not the hot Jupiters so much, at least not for me.

所以人们对这些非常感兴趣，我想，“嘿，推而广之，我们也关心更酷的世界。”并不是那么热的木星，至少对我来说不是。

It’s not the hot Neptunes.

这不是炎热的海王星。

It’s the planets that are further out in the temperate zone where life is possible, where moons can be possible, not because of the thermal temperature, but almost the dynamical temperature has cooled down.

那些位于温带较远的行星上才有可能存在生命，也有可能存在卫星，这不是因为热温度，而是因为动力温度几乎已经冷却下来。

So everything just gets more interesting when you’re far away from the star.

所以当你远离星星时，一切都会变得更加有趣。

So that was the story behind the name.

这就是这个名字背后的故事。

But you can make an anthropic argument that it’s perfectly consistent that the solar system could be the only place that has planets, and it would be perfectly natural that we would happen to be born in the one place where there are planets, ‘cause of course, we couldn’t be born anywhere else.

但你可以提出一个人择论，即太阳系可能是唯一有行星的地方，这是完全一致的，我们碰巧出生在有行星的地方是完全自然的，因为当然，我们不可能出生在其他任何地方。

So you could make that argument, but I think it would be surprising, a little bit intuitively, and indeed, once we started finding planets, it reinforced that view.

所以你可以提出这样的论点，但我认为这会令人惊讶，有点直观，事实上，一旦我们开始寻找行星，它就强化了这种观点。

But I think what’s really took us aback is just the diversity of worlds.

但我认为真正让我们吃惊的是世界的多样性。

I mean, we really expected the solar system to be a template of what other systems would look like, and it’s not, Janna.

我的意思是，我们真的希望太阳系成为其他系统的模板，但事实并非如此，詹娜。

It looks radically different from place to place, and that has really blown our minds.

每个地方看起来都截然不同，这确实让我们大吃一惊。

So before we were only really sensitive to largely Jupiter mass, Jupiter-size planets, and Kepler pushed us all the way down to Neptunes, super Earths and even some planets comparable to the size of the Earth.

因此，在此之前，我们只对木星质量、木星大小的行星非常敏感，而开普勒将我们一路推向海王星、超级地球，甚至一些与地球大小相当的行星。

So that blew us away.

这让我们大吃一惊。

But at the same time, I was thinking, “Hey, if we are able to detect Earth-sized planets, why couldn’t the universe be a little bit more creative and start making Earth-sized moons around Jupiter-sized planets?” And that was, yeah, really where I got into this idea of looking for moons.

但与此同时，我在想，“嘿，如果我们能够探测到地球大小的行星，为什么宇宙不能更有创造力一点，开始在木星大小的行星周围制造地球大小的卫星呢？”是的，这就是我真正产生寻找卫星想法的地方。

We really expected the solar system to be a template of what other systems would look like, and it’s not.

我们确实希望太阳系成为其他系统的模板，但事实并非如此。

It looks radically different from place to place, and that has really blown our minds.

每个地方看起来都截然不同，这确实让我们大吃一惊。

When you make a world—not necessarily just a planet or a moon—but just a world smaller and smaller, obviously, its surface gravity decreases, its escape velocity decreases, and thus it’s easier for gas, for an atmosphere to leak off through what’s called Jeans escape or even hydrodynamic escape if there’s ultraviolet radiation smashing into the top of the atmosphere.

当你创造一个世界时——不一定只是行星或月球——而只是一个越来越小的世界，显然，它的表面重力会减小，逃逸速度也会减小，因此气体和大气更容易通过所谓的“牛仔裤逃逸”或什至是流体动力逃逸（如果有紫外线辐射撞击大气层顶部）泄漏。

So those processes erode away atmospheres, and we think that’s why Mars doesn’t really have a thick atmosphere.

因此，这些过程会侵蚀掉大气层，我们认为这就是为什么火星实际上没有厚厚的大气层的原因。

The atmosphere of Mars is 0.6%, I think, the density of Earth’s atmosphere, yet it’s further away from the sun, so it should be easier in a thermal sense for it to hold onto an atmosphere.

我认为火星大气层的密度是地球大气层的0.6%，但它距离太阳更远，所以从热学意义上来说它应该更容易保持大气层。

But of course, it’s only 10% the mass of the Earth, so that explains it.

但当然，它的质量只有地球的 10%，这就解释了这一点。

We think that it probably did have a thick atmosphere in the past because we see all this evidence for liquid water.

我们认为它过去可能确实有厚厚的大气层，因为我们看到了所有这些液态水的证据。

We see these, riverbeds and river deltas and valleys that have been carved out by water.

我们看到这些，河床、河流三角洲和被水冲刷出来的山谷。

So it somehow lost it because it essentially wasn’t massive enough.

所以它不知何故失去了它，因为它本质上还不够大。

So therefore, that could be a problem.

因此，这可能是一个问题。

If you wanna have a habitable moon, you probably want it to be larger than that of Mars.

如果你想拥有一颗适合居住的卫星，你可能希望它比火星更大。

Otherwise, you might be restricted to things which are beneath the surface.

否则，你可能会被限制在表面之下的事情上。

And of course, there is interest in that with Europa, Enceladus, of subsurface life.

当然，人们对木卫二、土卫二和地下生命也很感兴趣。

But if something like, like we have, doing agriculture and a civilization, that might be difficult to have if you’re too small.

但如果像我们这样从事农业和文明，如果你太小，这可能很难实现。

And then, you know, you’ve got other factors like the axial tilt, and again, people argue about that.

然后，你知道，还有其他因素，例如轴向倾斜，人们再次对此争论不休。

You could think that an axial tilt is essential because if you had the North Pole pointed right at the sun for three months of the year or something, that would seem bad news for life.

你可能会认为轴向倾斜是至关重要的，因为如果一年中有三个月北极点正对着太阳或者什么的，这对生命来说似乎是个坏消息。

But on the other hand, we have extremophiles who seem very robust and can thrive in all sorts of environments.

但另一方面，我们的极端微生物看起来非常强壮，可以在各种环境中茁壮成长。

So maybe life would be fine without that?

那么如果没有这些，生活也许会很好？

But maybe it’s us really that we’re talking about.

但也许我们真正谈论的是我们自己。

You know, it’s agriculture.

你知道，这是农业。

It’s a Neolithic revolution.

这是一场新石器时代的革命。

Can you really do farming and have civilizations if your climate is wildly swinging?

如果你的气候剧烈波动，你真的能从事农业并拥有文明吗？

Like in Game of Thrones , you have these insane winters, right?

就像《权力的游戏》中一样，你也经历过疯狂的冬天，对吧？

But there may be a lot of other parallel tracks to the way life arrived here.

但生命到达这里的方式可能还有很多其他平行的轨迹。

Maybe on Titan.

也许在泰坦上。

Titan’s a very alien moon.

泰坦是一颗非常陌生的卫星。

It has methane and ethane lakes.

它有甲烷湖和乙烷湖。

Very, very different thing from the Earth.

与地球非常非常不同。

But perhaps there is life there—some form that we can’t really even imagine thriving on the Earth.

但也许那里存在生命——某种我们甚至无法想象在地球上繁衍生息的形式。

Yeah, so you’ve made the transition from just life, which could have been bacterial, to technologically sophisticated life, which sometimes is called intelligent life, but then that has all kinds of philosophical pit holes.

是的，所以你已经从普通的生命（可能是细菌）转变为技术复杂的生命，有时被称为智能生命，但它有各种各样的哲学漏洞。

And so you’ve just given this really interesting set of examples which are technological, space-faring civilizations that are trying to harness the energy and the resources, not only around them, but maybe of the entire galaxy, right?

所以你刚刚给出了这组非常有趣的例子，这些例子是技术性的太空文明，它们试图利用能源和资源，不仅是在它们周围，而且可能是整个银河系，对吗？

And that historically had a sort of origin in the Drake equation, which might have fallen out of favor, but really structured the conversation for a long time.

从历史上看，这在某种程度上起源于德雷克方程，该方程可能已经失宠，但确实在很长一段时间内构建了对话。

Can you tell us a little bit about the 1960s astronomer Frank Drake and what he was after in terms of trying to write an equation to predict the probability of the emergence of so-called intelligent life?

您能否向我们介绍一下 20 世纪 60 年代的天文学家弗兰克·德雷克 (Frank Drake)，以及他在尝试编写方程来预测所谓智慧生命出现的概率方面所追求的目标？

And so he had a little conference, and I believe there was only like seven or eight people at this conference, and it included evolutionary biologists, it included astronomers.

所以他召开了一个小型会议，我相信这次会议只有七八个人，其中包括进化生物学家，包括天文学家。

Carl Sagan was in attendance at this meeting famously.

卡尔·萨根因出席这次会议而闻名。

They called themselves the Order of the Octopus—I do know that.

他们称自己为章鱼骑士团——我确实知道这一点。

But I think ‘cause there was an octopus expert there, and they were inspired to name themselves the Order of the Octopus after he gave a great talk about octopuses.

但我认为是因为那里有一位章鱼专家，在他发表了关于章鱼的精彩演讲后，他们受到启发，将自己命名为“章鱼骑士团”。

It would have been a fascinating meeting to have been historically tracked.

如果能被历史记录下来，这将是一次令人着迷的会议。

But during that meeting, Frank Drake apparently wrote down the Drake equation for the first time, and the purpose of it was really to organize the meeting.

但在那次会议上，弗兰克·德雷克显然第一次写下了德雷克方程，其目的其实是为了组织这次会议。

And so it was a way of just like breaking out the problem into these bite-sized pieces.

因此，这就像将问题分解成这些小块一样。

You know, how often does life start?

你知道，生命多久开始一次？

How often does intelligence get going?

智力多久会出现一次？

How often do they communicate?

他们多久沟通一次？

Wasn’t really intended, in my interpretation, to be a calculator, and I think that’s where it’s been abused and why it has been sullied, over the years, because there have been numerous papers where astronomers have just plugged in numbers for the frequency of intelligence.

在我的解释中，它并不是真正的目的是成为一个计算器，我认为这就是它被滥用的地方，也是多年来它被玷污的原因，因为有很多论文，天文学家只是在其中插入了智力频率的数字。

And I mean, how does anyone know these numbers?

我的意思是，怎么有人知道这些数字？

It’s all just guesswork.

这一切都只是猜测。

For instance, we talked about these different qualities, like the axis of the Earth has to be tilted within a certain range or something.

例如，我们讨论了这些不同的品质，例如地球的轴必须在一定范围内倾斜或其他什么。

That’s not actually in the Drake equation, but you could imagine someone adding in more and more parameters like that.

这实际上并不在德雷克方程中，但你可以想象有人添加越来越多的这样的参数。

The fraction of civilizations that choose to communicate via radio.

选择通过无线电进行通信的文明的一部分。

Well, what about if they choose to communicate via something else?

那么，如果他们选择通过其他方式进行交流呢？

Its utility is questionable, I think.

我认为它的实用性值得怀疑。

And so for me, I was just interested in, you know, all models are wrong, but some models are useful.

所以对我来说，我只是感兴趣，你知道，所有模型都是错误的，但有些模型是有用的。

Make the model as simple as you can get away with.

让模型尽可能简单。

And the simplest model you can possibly imagine is that there is some rate at which these entities, civilizations, intelligence, whatever you wanna call them, emerge, and there’s some rate at which they die.

你能想象到的最简单的模型是，这些实体、文明、智慧，无论你想怎么称呼它们，都会以一定的速度出现，也会以一定的速度消亡。

And that’s useful to think about that way because then you would expect there to be an equilibrium over a certain amount of time after some settling time.

以这种方式思考是有用的，因为这样你就会期望在一段稳定时间后的一段时间内会达到平衡。

And so you can actually do that kind of calculation of what would be the settling time for given rates?

那么您实际上可以计算给定速率的稳定时间是多少？

And I think you can make a fairly convincing argument that given the age of the universe and the age of the galaxy right now, you would expect to be in the equilibrium state at this point.

我认为你可以提出一个相当令人信服的论点，考虑到现在宇宙的年龄和银河系的年龄，你会期望此时处于平衡状态。

And so that’s interesting, I think for just dialing it back to the simplest bare bones you can.

所以这很有趣，我认为只要将其拨回最简单的框架即可。

But it still leaves you ultimately with this question.

但它最终仍然给你留下了这个问题。

And so what we argued in this paper, is that the actual number of extant present-day civilizations out there ends up being dominated by purely the ratio of the birth and the death rate.

因此，我们在本文中主张的是，当今现存文明的实际数量最终纯粹由出生率和死亡率的比率决定。

That’s it.

就是这样。

So it’s actually just one number, the birth to death ratio.

所以它实际上只是一个数字，即出生死亡率。

That’s all that matters.

这才是最重要的。

In statistics, we often want priors, right?

在统计学中，我们经常需要先验，对吗？

To predict a distribution, you have to have some distribution that you assume for the birth to death ratio.

要预测分布，您必须有一些假设的出生死亡比分布。

And so we argued that the most agnostic and least informative prior if you plug it in, it ends up giving you a very bifurcated distribution.

因此我们认为，如果你将它插入到最不可知论和信息最少的先验中，它最终会给你一个非常分叉的分布。

So you end up with there either being a very crowded universe or a very lonely universe.

所以最终要么是一个非常拥挤的宇宙，要么是一个非常孤独的宇宙。

It’s very difficult to get it intermediate.

中间很难做到。

Aliens is like the Band-Aid explanation.

外星人就像创可贴的解释。

Because it’s too flexible as a hypothesis.

因为它作为一个假设太灵活了。

It can explain anything you want.

它可以解释你想要的任何事情。

And I think this intuitively makes sense.

我认为这直观上是有道理的。

There was a physiologist John Haldane about a century ago who pointed this out.

大约一个世纪前，生理学家约翰·霍尔丹就指出了这一点。

He said, “Well, imagine you approached a bench and there was beakers of water, and the beakers of water are almost the same.” They have more or less the same temperature, the same salinity, but there might be slight differences between them.

他说：“好吧，想象一下你走近一张长凳，那里有烧杯水，而烧杯里的水几乎是一样的。”它们的温度、盐度大致相同，但它们之间可能存在细微差别。

And then you have some random chemical, let’s call it chemical X, and you’re gonna pour it into these 20, 30 beakers, let’s say.

然后你有一些随机的化学物质，我们称之为化学物质 X，你要把它倒入这 20、30 个烧杯中，比方说。

And his challenge to the listener was this: What fraction of the time would you expect this random chemical X to dissolve amongst these beakers?

他向听众提出的挑战是：您期望这种随机化学物质 X 溶解在这些烧杯中的时间是多少？

And he reasoned that you should expect either it to be almost 100% or 100%, or almost 0% or 0%.

他推断，你应该预期它要么接近 100% 或 100%，要么接近 0% 或 0%。

But it’d be very weird if half of the time this chemical dissolved in the water and half of the time it didn’t, given the water is more or less the same water.

但如果这种化学物质一半的时间溶解在水中，一半的时间不溶解，那就很奇怪了，因为水或多或少是相同的水。

It’s more or less the same stuff each time.

每次或多或少都是相同的东西。

And so by the same extension, there’s all these Earth-like planets out there.

因此，通过同样的扩展，那里存在所有这些类地行星。

You would expect that once the rules are in place, if life is the way it goes, then life will just pop up everywhere.

你可能会期望，一旦规则到位，如果生活就是这样，那么生活就会随处出现。

Or it’s incredibly unlikely to get to life, and therefore we would necessarily live in one of those rare places.

或者它不太可能获得生命，因此我们必然生活在那些稀有的地方之一。

So we kind of argued this bifurcation that you would end up with either a crowded universe or a lonely universe.

所以我们认为这种分歧最终要么是一个拥挤的宇宙，要么是一个孤独的宇宙。

And then we more provocatively said that we think the crowded universe is, certainly for technology, incompatible with observations.

然后我们更具挑衅性地说，我们认为拥挤的宇宙，当然对于技术而言，与观测不相容。

It is a very quiet cosmos out there.

那里是一个非常安静的宇宙。

And certainly the universe is not screaming.

当然，宇宙并没有尖叫。

It is not full.

它还没有满。

It is not saturated with radio transmitters.

它的无线电发射机尚未饱和。

We are absolutely confident that is not the case.

我们绝对相信事实并非如此。

So in this framework where you would expect to have either crowded or empty, it more or less rules that out ab initio .

因此，在这个框架中，您期望要么拥挤要么空旷，它或多或少从头开始就排除了这一点。

It’s done.

完成了。

You can’t possibly have that.

你不可能拥有那个。

So therefore, in our thinking, a SETI optimist has to live in this valley where it’s not zero, but it’s not 100%.

因此，在我们看来，SETI 乐观主义者必须生活在这个数值不为零但也不是 100% 的山谷中。

And they are hoping that basically 10 more years of SETI will push us just over the edge from 55% coverage to, you know, there’ll just be enough that you’ll get over.

他们希望，基本上 10 年的 SETI 能够将我们从 55% 的覆盖率推向边缘，你知道，就足够你克服了。

And we just argue that’s statistically very unlikely that you’d live on that knife edge where we’re just behind the curve.

我们只是认为，从统计数据来看，你不太可能生活在我们落后于曲线的刀刃上。

So I don’t want to say don’t do SETI, ’cause it’s always a surprise, especially if we’re gonna in different ways rather than radio SETI, looking for laser signals, thinking about other means of communication, even neutrino beams, gravitational waves.

所以我不想说不要做 SETI，因为它总是令人惊讶，特别是如果我们要以不同的方式而不是无线电 SETI，寻找激光信号，考虑其他通信方式，甚至中微子束、引力波。

But I think looking for simple life is a complete unknown.

但我认为寻找简单的生活是一个完全未知的事情。

Like in that dichotomy of crowded or empty, it could be full.

就像拥挤或空旷的二分法一样，它也可能是满的。

Like Mars could have life beneath its surface, Europa, Enceladus.

就像火星、木卫二、土卫二的表面下可能有生命一样。

We have no constraint on that.

我们对此没有任何限制。

It’s just that for whatever reason, it doesn’t ever get to radio transmitters all over the place.

只是无论出于何种原因，它都无法到达各处的无线电发射器。

So in a way, you seem to be saying that just statistically using that kind of analysis, technology might be rare, but life could still be plentiful—just simpler life.

因此，在某种程度上，你似乎是在说，仅使用这种分析进行统计，技术可能很罕见，但生活仍然可以丰富——只是生活更简单。

But I think today it seems quite prescient.

但我认为今天看来这是很有先见之明的。

It seems possible.

看来有可能。

There was a recent study that estimated a machine now could reproduce 70% of its mass.

最近的一项研究估计，机器现在可以复制其质量的 70%。

So we’re 70% of the way there to a self-replicating probe.

所以我们已经完成了自我复制探针的 70%。

It’s not that hard to imagine someone launching one of these things.

不难想象有人推出其中一款产品。

And in some extreme versions of this, you could imagine it just propagating across the galaxy—1% the speed of light is plenty—and you could convert the entire galaxy into computer substrate, which the galaxy just becomes a giant data center in space for AI training or something.

在一些极端的版本中，你可以想象它只是在银河系中传播——1%的光速就足够了——你可以将整个银河系转换成计算机基板，银河系就变成了一个巨大的太空数据中心，用于人工智能训练或其他什么。

It does feel very prescient right now, and that clearly has not happened.

现在确实感觉很有先见之明，但显然这还没有发生。

The galaxy hasn’t been converted into a giant computer substrate because otherwise we wouldn’t be here.

银河系还没有被改造成一个巨大的计算机基板，否则我们就不会在这里。

So Tipler argued that this is the strongest constraint that we have.

因此蒂普勒认为这是我们拥有的最强的限制。

This requires that less than one in a hundred billion stars ever produces self-replicating probes that just do their own thing.

这就要求只有不到千亿分之一的恒星能够产生只做自己事情的自我复制探针。

Now, however contrived you think that might be, one in a hundred billion is a really small odds for, like, just someone somewhere has to do it once.

现在，无论你认为这有多么做作，对于某些人来说，千亿分之一的可能性确实很小，就像某个地方的某个人必须这样做一次。

And so Sagan didn’t like that because Sagan was an optimist, and so he was pushing back saying, you know, there’s all these reasons, like the probe might have finite range.

所以萨根不喜欢这样，因为萨根是一个乐观主义者，所以他反驳说，你知道，有所有这些原因，比如探测器的射程可能有限。

It might be like there’s a zoo hypothesis.

这可能就像有一个动物园假说。

Aliens is watching us.

外星人正在注视着我们。

It’s like the Star Trek Prime Directive a little bit.

这有点像《星际迷航：最高指令》。

But, all of those have been studied really in-depth.

但是，所有这些都经过了非常深入的研究。

We could talk about any of them, but they’ve all been thrown aside, largely.

我们可以谈论其中任何一个，但它们基本上都被抛在了一边。

And I think the original claim by Tipler that this is really difficult to reconcile with our very existence, that self-replicating machine has never done this.

我认为蒂普勒最初的说法是，这真的很难与我们的存在相协调，自我复制机器从未做到过这一点。

The universe has not woken up.

宇宙还没有苏醒。

Matter has not transformed into intelligent substrate at this point.

此时物质还没有转变为智能基质。

Apart from like our brains maybe.

也许除了我们的大脑之外。

And so that, that is kind of a profound constraint on what happens in the universe.

因此，这对宇宙中发生的事情是一种深刻的限制。

And then the idea of more specific evidence for UFOs, it’s mostly actually personal testimony.

然后是关于不明飞行物的更具体证据的想法，这实际上主要是个人证词。

But the actual videos we’ve seen—not very convincing.

但我们看到的实际视频并不十分令人信服。

So you know, there’s these three videos the Pentagon released.

所以你知道，五角大楼发布了这三个视频。

There’s no range information on any of that.

没有任何关于这些的范围信息。

So it’s very difficult to know whether you’re looking at something like right in front of you in the foreground or far away.

因此，很难知道您正在看的是前景中的物体，还是远处的物体。

And the pilot said, “Oh, no, I had a good idea of where it was.

飞行员说：“哦，不，我很清楚它在哪里。

I knew where it was.” But it’s not reproducible and of course, science is all about reproducibility.

我知道它在哪里。”但它是不可重复的，当然，科学就是可重复性。

If you can’t reproduce it we just don’t know what to do with that.

如果您无法重现它，我们只是不知道该怎么办。

So I think, in a nutshell, my big issue with the UFO claims has been that we can’t even ingest it into science.

所以我认为，简而言之，我对不明飞行物声称的最大问题是我们甚至无法将其纳入科学。

If I’m going to ingest any scientific claim, I need to know two numbers: the false positive rate of that experiment and its true positive rate.

如果我要接受任何科学主张，我需要知道两个数字：该实验的假阳性率和真阳性率。

And I’ve proven this in a Bayesian paper, there’s no way to interpret an experiment if you don’t know those two numbers.

我在贝叶斯论文中证明了这一点，如果你不知道这两个数字，就无法解释实验。

Because if your false positive rate is 99% and someone says, “I saw a UFO,” it’s almost certainly a false positive.

因为如果你的误报率为 99%，而有人说“我看到了不明飞行物”，那么几乎肯定是误报。

You have to know these numbers in order to make sense of it.

您必须了解这些数字才能理解它们。

There’s no way to even ingest these claims into science as they currently stand.

目前还没有办法将这些主张纳入科学。

My big issue with the UFO claims has been that we can’t even ingest it into science.

我对不明飞行物声称的最大问题是我们甚至无法将其纳入科学。

So yes, there’s a lot of planets and star systems and moons within that range, but we haven’t had civilizations for hundreds of thousands of years.

所以，是的，这个范围内有很多行星、恒星系统和卫星，但我们已经有数十万年没有文明了。

We’ve had civilization, as you said, really just for a few thousand, and we’ve only had technology for a couple hundred years, right?

正如你所说，我们的文明只有几千年的历史，而我们的技术也只有几百年的历史，对吗？

A couple hundred years, and it’s unclear that our technology is sustainable, that we’ll be able to keep having electricity and energy for everybody on this planet sustainably.

几百年后，我们的技术是否可持续，我们是否能够持续为这个星球上的每个人提供电力和能源，尚不清楚。

So we might only have had a few hundred years of technology total, and that might be it.

因此，我们的技术总共可能只有几百年的历史，仅此而已。

So you’re talking about trying to overlap across these incredibly vast spatial distances in this incredibly long timescales in a bleep, right?

所以你说的是尝试在这个令人难以置信的长时间尺度上重叠这些令人难以置信的广阔的空间距离，对吗？

An absolute bleep.

绝对是哔哔声。

And then it becomes, well, if we do overlap, then probably there are a whole huge ton of civilizations ’cause then they’re in our backyard, and they came really close, and then by coincidence, they overlapped with us in time.

然后，如果我们确实重叠，那么可能存在大量的文明，因为它们就在我们的后院，而且它们非常接近，然后巧合的是，它们及时与我们重叠。

And if we don’t, well, you know, that kind of seems like, yeah, maybe that’s just the odds.

如果我们不这样做，那么，你知道，看起来，是的，也许这只是可能性。

Welcome back to The Joy of Why .

欢迎回到“为什么的喜悦”。

We’ve been speaking with Columbia University astronomer David Kipping about the probability of life in our universe.

我们一直在与哥伦比亚大学天文学家大卫·基平讨论宇宙中存在生命的可能性。

So you’ve used this sort of deep statistical thinking not just to analyze theoretical concepts like the Drake equation, but really importantly, to actually search for places where life might emerge, and we already mentioned it lightly, but the idea that moons are a really interesting place to consider.

因此，您不仅使用这种深入的统计思维来分析德雷克方程等理论概念，而且非常重要的是，实际寻找可能出现生命的地方，我们已经简单地提到了这一点，但卫星是一个非常值得考虑的有趣地方。

From our own experience in our system moons are plentiful.

根据我们自己在我们系统中的经验，卫星是丰富的。

There are hundreds of moons in our solar system, which is really kind of amazing.

我们的太阳系中有数百个卫星，这真是令人惊奇。

What advantage are the exomoons offering you over an exoplanet in the search for life?

在寻找生命的过程中，与系外行星相比，系外卫星有什么优势？

Then there’s just the pure, like, uniqueness question.

然后就是纯粹的、独特性的问题。

Maybe come back down to that more kind of mechanistic astrophysicist view.

也许回到机械天体物理学家的观点。

Just how did we get here?

我们是怎么到这里的？

What’s our origin story?

我们的起源故事是什么？

Is the Moon like a one-off fluke that just very rarely happens, or is that an inevitable part of terrestrial planet formation, that you end up with these large, almost quasi-binary objects?

月球是一种非常罕见的一次性事件，还是类地行星形成过程中不可避免的一部分，最终会形成这些巨大的、几乎是双星的物体？

There’s lots of strange moons, and it’s like Triton goes around backwards around its parent planet.

有很多奇怪的卫星，就像海卫一绕着它的母星倒转一样。

You’ve got Uranus tilted over with its moon system.

天王星及其卫星系统倾斜了。

So there’s lots of curiosities in the solar system that from a singular example, it’s difficult to know, like, really how does this story play out in other environments.

因此，太阳系中有很多令人好奇的地方，从一个单一的例子来看，很难知道这个故事在其他环境中到底是如何发生的。

So I think just uniqueness is another reason.

所以我认为独特性是另一个原因。

And the fourth one is kind of subtle, and that’s thinking about next generation missions.

第四个有点微妙，那就是考虑下一代任务。

I mentioned we wanna build a successor to James Webb one day, probably called at the moment the Habitable Worlds Observatory, HWO.

我提到我们希望有一天能够建造詹姆斯·韦伯的继任者，目前可能被称为宜居世界观测站，HWO。

But it will hopefully one day take a photo of another Earth.

但希望有一天它能拍到另一个地球的照片。

It’ll be a single pixel.

它将是一个像素。

It’ll be a single blob of light.

它将是一团光。

They’re like the pale blue dot.

它们就像淡蓝色的点。

And from that pale blue dot, we’ll split the light up into a rainbow, essentially like the prism, like Newton did, and we’ll look for those atmospheric biosignatures that we’re so interested in.

从那个淡蓝色的点，我们将把光分成彩虹，本质上就像棱镜，就像牛顿所做的那样，我们将寻找那些我们非常感兴趣的大气生物特征。

And moons here can really screw us over.

这里的卫星真的可以把我们搞砸。

If anyone’s ever seen that famous pale blue dot image that I think it was Voyager 1 took, as it looked back at, sort when it was like the orbit of Neptune.

如果有人见过那张著名的淡蓝色圆点图像，我想那是航行者一号拍摄的，当它回头看时，排序它就像海王星的轨道一样。

It turned around, it looked back and took a picture of the Earth.

它转过身来，回头看了一眼，拍下了地球的照片。

It’s this beautiful image if you’ve never seen it before.

如果您以前从未见过，这就是这张美丽的图片。

And in that image, it’s not a pale blue dot, even though Sagan described it as a pale blue dot.

在该图像中，它不是一个淡蓝色的点，尽管萨根将其描述为一个淡蓝色的点。

It’s a pale blue-gray dot because the Moon’s in there.

它是一个淡蓝灰色的点，因为月亮在那里。

The Moon’s right, it’s photobombing right along, right?

月亮是对的，它正在轰炸，对吧？

You can’t distinguish it.

你无法区分它。

You can’t separate it.

你无法将它分开。

They’re just one smudge of light.

它们只是一抹光。

So when HWO takes these images, it’s gonna be in the same situation.

所以当 HWO 拍摄这些图像时，也会处于同样的情况。

It’s seeing what it thinks is a planet, but it’s really a planet plus however many moons it has.

它看到了它认为是一颗行星的东西，但它实际上是一颗行星加上无论它有多少卫星。

And when we look at moons like Titan.

当我们观察像泰坦这样的卫星时。

Titan has a methane atmosphere, methane lakes.

土卫六有甲烷大气层、甲烷湖。

It’s full of interesting hydrocarbons.

它充满了有趣的碳氢化合物。

You could easily, if you didn’t know that was a separate moon, get confused.

如果你不知道那是一颗独立的卫星，你很容易会感到困惑。

You could imagine having an ocean world, a terrestrial ocean world, where the water undergoes photolysis, and that means that the H2O splits into hydrogen and oxygen.

你可以想象有一个海洋世界，一个陆地海洋世界，其中的水进行光解，这意味着水分解成氢气和氧气。

So you’ve got an oxygen-rich planet.

所以你有一个富含氧气的星球。

No life involved, just oxygen from UV radiation.

不涉及生命，只有紫外线辐射产生的氧气。

That’s it.

就是这样。

And then you’ve got Titan mixed in there, which has methane.

然后泰坦混入其中，其中含有甲烷。

So now, from the astronomer’s perspective, everything looks beautiful.

所以现在，从天文学家的角度来看，一切看起来都很美丽。

You’ve got methane, you’ve got ozone, you’ve got oxygen.

你有甲烷，你有臭氧，你有氧气。

You’d be like, “We’re done.

你会说：“我们完成了。

That’s life.” But it’s a confounder.

这就是生活。”但这是一个混杂因素。

It’s just something we hadn’t thought of.

这只是我们没有想到的事情。

So that’s why I think moons are really important.

这就是为什么我认为月亮非常重要。

I don’t know how we could even look for life with HWO unless we resolve the moon problem.

我不知道除非我们解决月球问题，否则我们如何利用 HWO 寻找生命。

There’s so much we don’t know about chemistry and geochemistry and other planetary environments that it feels like we are doomed to always be caught out by those things.

关于化学、地球化学和其他行星环境，我们有太多不了解的地方，感觉我们注定要永远被这些东西所困扰。

And I think what we know for sure is that Kepler, which as I said, was this transformative mission, had this sensitivity down to about Earth-sized stuff – moons, planets, whatever it.

我想我们可以肯定的是，正如我所说，开普勒是一项变革性的任务，它对地球大小的物体——卫星、行星，等等——都有这种敏感性。

And it really didn’t throw out many candidates.

而且它确实没有淘汰很多候选人。

There’s just not a lot there.

那里的东西并不多。

So out of the 4,000, 5,000 candidate exoplanets, we have just a couple of hints of moons in that entire database.

因此，在 4,000、5,000 颗候选系外行星中，我们在整个数据库中只找到了一些卫星的线索。

So that already tells you Earth-sized moons are not that normal.

所以这已经告诉你地球大小的卫星并不那么正常。

I’m not saying they never happen, but they’re certainly not par for the course.

我并不是说它们永远不会发生，但它们肯定不符合标准。

We did find a couple of interesting candidates that I hinted at there, but they both have been very surprising because they’re so large.

我们确实发现了我在那里暗示的几个有趣的候选者，但它们都非常令人惊讶，因为它们太大了。

They are Neptune-sized or even mini Neptune-sized moons orbiting Jupiter-sized or super-Jupiter-mass planets.

它们是海王星大小甚至迷你海王星大小的卫星，围绕木星大小或超木星质量的行星运行。

So nobody really expected that.

所以没有人真正预料到这一点。

I mean, reminds me a bit of hot Jupiters, some of the first exoplanets ever found.

我的意思是，这让我想起了一些热木星，这是有史以来第一批发现的系外行星之一。

They’re Jupiter-like worlds but are about 10 times closer to their star than Mercury is around the sun.

它们是类似木星的世界，但距离恒星的距离大约是水星绕太阳距离的十倍。

But we now know they’re definitely real because we’ve just found like so many of them, and it still puzzles us how they got there.

但我们现在知道它们绝对是真实的，因为我们刚刚发现了很多这样的东西，但我们仍然困惑它们是如何到达那里的。

We still don’t understand it.

我们还是不明白。

And so we found these two large moons.

所以我们发现了这两颗大卫星。

1625b-i And then there’s also Kepler-1708b-i.

1625b-i 然后还有 Kepler-1708b-i。

So the b is the planet, the number plate is the star, and then the -i is the moon.

所以 b 是行星，车牌是恒星，然后 -i 是月亮。

Those are the only two we’ve found.

这是我们找到的仅有的两个。

Other teams have seen hints in different observations as well.

其他团队也在不同的观察中看到了暗示。

No one yet has like a crisp, clear slam dunk signal.

目前还没有人发出像这样清脆、清晰的灌篮信号。

And I think that’s what we really need.

我认为这就是我们真正需要的。

The field’s in desperate need of that kind of clear signal.

该领域迫切需要这种明确的信号。

Obviously, a big thing close to the star is the easiest signal you can possibly get.

显然，靠近恒星的大物体是最容易获得的信号。

And I think a general story in astronomy is that often the first examples of things we discover are not typical.

我认为天文学中的一个普遍现象是，我们发现的第一个例子通常并不典型。

They’re often very unusual beasts, and the reason we find them first is ’cause they’re so loud.

它们通常是非常不寻常的野兽，我们首先发现它们的原因是它们的声音太大。

They’re disproportionate.

他们不成比例。

They’re tail-end members of their population.

他们是人口的尾端成员。

They’re not representative.

他们不具有代表性。

And so it wouldn’t surprise me if these things turn out to be real, but they’re still requiring follow-up to ultimately figure out what they are.

因此，如果这些事情被证明是真实的，我不会感到惊讶，但它们仍然需要后续行动才能最终弄清楚它们是什么。

But James Webb has been opening up a lot of doors for that.

但詹姆斯·韦伯已经为此打开了很多大门。

Another experiment we’ve been doing is actually measuring the oblateness of exoplanets, which has never been done before.

我们一直在做的另一个实验实际上是测量系外行星的扁率，这是以前从未做过的。

But you can actually tell whether the planet is a pure sphere, or slightly ellipsoidal—which of course planets really are.

但你实际上可以分辨出这颗行星是纯球体还是略呈椭球体——当然行星确实是这样的。

They’re oblate spheroids, because as they rotate, they bulge out at the sides.

它们是扁球体，因为当它们旋转时，它们的侧面会凸出。

And so they get these kind of love handles, like the Earth has, you know, slightly wider equator than it does the North-South Pole.

所以他们得到了这种爱的把手，就像地球的赤道比南北两极稍宽一样。

And Saturn’s actually pretty extreme.

土星实际上相当极端。

That’s actually quite detectable with James Webb.

詹姆斯·韦伯（James Webb）实际上很容易察觉到这一点。

So it’s such an impressive machine.

所以这是一台令人印象深刻的机器。

There’s no need to use it to find planets, ’cause it can really characterize the planets, and especially atmospheres.

没有必要用它来寻找行星，因为它可以真正描述行星的特征，尤其是大气层。

And even in those very favorable conditions, the signal we’re looking for is that the planet effectively appears different sizes at different wavelengths of light, and the wavelengths of light corresponding to, say, ozone absorption, you see the planet puff up a little bit.

即使在那些非常有利的条件下，我们正在寻找的信号是，行星在不同波长的光下实际上呈现出不同的大小，并且对应于臭氧吸收的光波长，您会看到行星有点膨胀。

And what that’s telling us is that there’s a molecule, ozone in that case, that really likes to absorb that wavelength of light and therefore make the planet appear a little bit larger.

这告诉我们，有一种分子，即臭氧，非常喜欢吸收该波长的光，从而使地球看起来更大一些。

So we think that’s how you would potentially detect ozone.

所以我们认为这就是检测臭氧的潜在方法。

It’s just that the telescope isn’t quite sensitive enough, unfortunately, to get most of those biosignatures.

不幸的是，只是望远镜不够灵敏，无法获得大部分生物特征。

We think of things like methane, ozone, phosphine, dimethyl sulfide has been proposed recently as well.

我们认为最近也提出了诸如甲烷、臭氧、磷化氢、二甲硫醚之类的物质。

There was a claim actually of dimethyl sulfide, maybe some your listeners might know in that using James Webb, but it’s really spectacular levels compared to what we have on the Earth, so a lot of people are skeptical it’s remotely possible that could be a biosignature.

实际上有一种说法是二甲硫醚，也许你的一些听众可能知道詹姆斯·韦伯的说法，但与我们在地球上所拥有的相比，它的水平确实非常惊人，所以很多人怀疑这是否有可能是一种生物特征。

There’s just way too much of it to make sense for certainly an Earth-like biosphere.

对于类似地球的生物圈来说，它的意义实在是太大了。

But there’s a lot of controversy with some of these detections, but I think most of my colleagues think that it’s just beyond the ability of James Webb to detect biosignatures, but that’s fine.

但其中一些检测存在很多争议，但我认为我的大多数同事都认为这超出了詹姆斯·韦伯检测生物特征的能力，但这没关系。

Probably a more basic question you might ask is, do Earth-like planets even have atmospheres to begin with?

您可能会问的一个更基本的问题是，类地行星是否有大气层？

Or are they barren rocks?

或者它们是荒芜的岩石？

’Cause the Moon doesn’t have an atmosphere, Mars doesn’t have much of an atmosphere, Mercury doesn’t have an atmosphere.

因为月球没有大气层，火星没有大气层，水星没有大气层。

And so there’s a huge program right now with James Webb called the Cosmic Shoreline Program, which is to look at a group of planets which are Earth-sized in the habitable zones of their stars.

因此，詹姆斯·韦伯现在有一个名为“宇宙海岸线计划”的庞大计划，该计划旨在观察位于其恒星宜居带中的一组地球大小的行星。

And the question is whether the planets even have atmospheres, because M dwarfs are quite active.

问题是这些行星是否有大气层，因为 M 矮星非常活跃。

They throw out these huge coronal mass ejections, these stellar flares, and so there is a concern that maybe the atmospheres are gone.

它们抛出了这些巨大的日冕物质抛射，这些恒星耀斑，所以人们担心大气层可能已经消失了。

Maybe these planets can’t even sustain an atmosphere.

也许这些行星甚至无法维持大气层。

James Webb can answer that question, so that’s what this program’s doing.

詹姆斯·韦伯可以回答这个问题，所以这就是这个程序正在做的事情。

So it should be able to tell whether Earth-sized habitable zone planets have an atmosphere or not.

因此它应该能够判断地球大小的宜居带行星是否有大气层。

And that would already be a massive breakthrough.

这已经是一个巨大的突破了。

I mentioned very briefly the Allan Hills meteor, which was a rock on Mars 4 billion years ago that knocked off, it landed on the Earth, landed in Antarctica, I think in 1984 or something.

我非常简短地提到了艾伦·希尔斯流星，它是 40 亿年前火星上的一块岩石，它脱落后落在地球上，落在南极洲，我想是在 1984 年左右。

And they collected it, they studied it, and they found these, like things which looked like little worms under the electron microscope.

他们收集了它，研究了它，他们发现了这些，就像电子显微镜下看起来像小蠕虫的东西。

And so that was essentially a biosignature.

所以这本质上是一个生物特征。

It’s not a gas, but it is a biosignature.

它不是气体，而是一种生物特征。

It’s a signature of biology.

这是生物学的标志。

And it turned out that even though it looked like life, other geochemists and scientists were able to show that you can make structures like that without biology involved whatsoever, just basically through water and high pressure water in particular.

事实证明，尽管它看起来像生命，但其他地球化学家和科学家能够证明，你可以在不涉及任何生物学的情况下制造出这样的结构，基本上只需通过水，特别是高压水。

And so that really killed the momentum behind that claim.

这确实扼杀了这一主张背后的动力。

Another example, if we go really far back, would be Martian canals.

另一个例子，如果我们追溯到很久以前，就是火星运河。

Seems silly now, but Percival Lowell—he thought there was canals on Mars ’cause he thought that was a biosignature.

现在看来很愚蠢，但珀西瓦尔·洛厄尔——他认为火星上有运河，因为他认为这是一个生物特征。

He saw these lines on Mars, and he thought, “I know what causes that.

他在火星上看到了这些线条，他想：“我知道是什么原因造成的。

It’s a canal system.” So often we are tripped by what we don’t know.

这是一个运河系统。”我们常常被我们不知道的事情绊倒。

It’s not Percival Lowell’s fault that he didn’t know about those psychological biases ’cause nobody had published on them yet.

珀西瓦尔·洛厄尔不了解这些心理偏见并不是他的错，因为还没有人发表过有关这些偏见的文章。

And a very recent example was DMS, dimethyl sulfide.

最近的一个例子是 DMS（二甲硫醚）。

Dimethyl sulfide was claimed, as we mentioned earlier, in the, in an exoplanet atmosphere recently, K2-18b.

正如我们之前提到的，最近在系外行星大气层中的 K2-18b 中发现了二甲硫醚。

Cambridge University did a huge press release talking about this being, you know, a historic moment in the search for life.

剑桥大学发布了一份大型新闻稿，谈论这是寻找生命的历史性时刻。

But we now know that DMS is on comets in the solar system.

但我们现在知道 DMS 存在于太阳系的彗星上。

Unless you think there’s living creatures on all the comets, it seems difficult to believe that this is an unambiguous biosignature anymore.

除非你认为所有彗星上都有生物，否则似乎很难相信这是一个明确的生物特征。

So just time after time after time, it’s like Groundhog Day, Janna.

所以一次又一次，就像土拨鼠日一样，迦娜。

You just keep waking up, we hear these claims of life, and then we all know what’s gonna happen.

你只要不断醒来，我们就会听到这些关于生命的说法，然后我们都知道会发生什么。

Happens every time.

每次都会发生。

It just dissolves.

它只是溶解了。

So I’ve been thinking about this really hard recently.

所以我最近一直在认真思考这个问题。

And yeah, I do kind of make the case that I think the current approach we’re using just will never work, and we do need to really rethink how we do this.

是的，我确实认为我们目前使用的方法永远不会奏效，我们确实需要重新思考如何做到这一点。

So the confounder rate’s the same between the two samples, but the life rate is different.

所以两个样本之间的混杂率是相同的，但寿命是不同的。

And so really then you’re doing a differential measurement.

那么你实际上是在进行差分测量。

Any difference you observe in biosignatures between those two populations, therefore, in a differential sense, has to be due to life.

因此，从差异的意义上来说，你在这两个群体之间观察到的任何生物特征差异都必须归因于生命。

It doesn’t tell you how much life there is in an absolute sense.

它并没有告诉你绝对意义上有多少生命。

You still don’t know, but you know that that excess must be driven by life.

你仍然不知道，但你知道这种过度一定是由生活驱动的。

So that statistically is very clean.

所以统计数据是非常干净的。

It resolves a lot of these problems and these unknowns.

它解决了很多这样的问题和未知数。

But you might reasonably question whether it’s even possible to set up such an experiment, and that’s what I’m thinking about now.

但你可能会合理地质疑是否有可能进行这样的实验，这就是我现在正在考虑的问题。

It is perfectly consistent with everything we know about the universe that we are alone.

我们是孤独的，这与我们所知道的关于宇宙的一切完全一致。

There’s nothing we know about the universe that rules that out.

我们对宇宙一无所知，无法排除这种可能性。

I think the only exception to this I can imagine is actually a really strong information-rich SETI signal.

我认为我能想象到的唯一例外实际上是一个非常强大、信息丰富的 SETI 信号。

So if it was like a laser beam with a video transmission encoded within it, there’s just no plausible natural confounder to that.

因此，如果它就像一束激光束，其中编码了视频传输，那么就没有合理的自然混杂因素。

You just can’t imagine it.

你根本无法想象。

It just seems impossible.

这似乎是不可能的。

But with biosignatures, those gases are very information weak.

但对于生物特征来说，这些气体的信息非常薄弱。

Really, all you measure is that gas is there and an abundance maybe, if you’re lucky.

事实上，你所测量到的只是那里有天然气，而且如果你幸运的话，可能还很丰富。

And that’s about it.

就是这样。

So it’s that informatics perspective, I think, that really endangers biosignatures.

所以我认为，正是信息学的观点真正危及了生物特征。

They just don’t carry a lot of information to begin with.

它们一开始就没有携带很多信息。

However, am I an optimist or a pessimist?

然而，我是乐观主义者还是悲观主义者？

I’d honestly try to be, it’s a little bit of a cop-out, but agnostic and forcefully agnostic because I’m so terrified of experimenter’s bias.

老实说，我会尽力做到这一点，这有点逃避现实，但我是不可知论者，而且是强烈的不可知论者，因为我非常害怕实验者的偏见。

And we’ve seen this so many times in history of scientists even claiming life, claiming this comet is an interstellar ship, claiming this little rock on Mars is a face, claiming this fossil from the Allan Hills meteor—Bill Clinton stood on the White House lawn and talked about that as evidence for life on Mars, and now nobody believes it.

我们在历史上已经多次看到科学家声称存在生命，声称这颗彗星是一艘星际飞船，声称火星上的这块小岩石是一张脸，声称这块化石来自艾伦山流星——比尔·克林顿站在白宫草坪上谈论这是火星上存在生命的证据，但现在没有人相信。

So many times we’ve got caught up in that excitement of optimism, and I think the lesson for me has always been like just try and remain sober.

很多时候，我们都陷入了乐观的兴奋之中，我认为对我来说，教训就是尽量保持清醒。

Just try and look at it objectively and require those high standards of evidence that we apply in all other aspects of our science.

只要尝试客观地看待它，并要求我们在科学的所有其他方面应用这些高标准的证据即可。

It is not different when we look for life.

当我们寻找生命时，情况并没有什么不同。

So I try to remain objective, and I think honestly, it is perfectly consistent with everything we know about the universe that we are alone.

所以我努力保持客观，老实说，这与我们对宇宙的了解完全一致，即我们是孤独的。

There’s nothing we know about the universe that rules that out.

我们对宇宙一无所知，无法排除这种可能性。

It is within the realms of possibility.

这是在可能性范围之内的。

Like, I always get a little bit depressed when we’re asked sometimes as scientists to defend the technologies or industrial applications of searching the universe for gravitational waves or something.

就像，当我们作为科学家有时被要求捍卫在宇宙中寻找引力波或其他东西的技术或工业应用时，我总是有点沮丧。

Sure, there is many side benefits, and we can list those off.

当然，还有很多附带好处，我们可以一一列举。

But in a very pure sense, the reason for doing it is the same reason why we do poetry.

但从非常纯粹的意义上来说，这样做的原因与我们创作诗歌的原因是一样的。

It’s the same reason why we do art.

这和我们做艺术的原因是一样的。

It’s that, what is the point of being on this Earth if our sole interest is bread on the table, feeding myself, going to sleep, waking up the next day, going back to work, and that’s your whole life?

就是说，如果我们唯一的兴趣就是桌上的面包、自己吃饭、睡觉、第二天醒来、回去工作，这就是你的全部生活，那么我们在这个地球上还有什么意义呢？

It’s just this pure machine-like process.

这只是一个纯粹的类似机器的过程。

We’re more than that, I believe.

我相信，我们不仅如此。

And I think looking out and wondering about the universe, it enriches our soul, enriches our human nature.

我认为向外观察并思考宇宙，它丰富了我们的灵魂，丰富了我们的人性。

I would hate to live in a world where we didn’t ask these questions.

我讨厌生活在一个我们不问这些问题的世界。

And I think it’s a real privilege, certainly, that I’ve had a career where I’ve been able to dwell on some of these questions and think about them so much.

我认为这确实是一种荣幸，在我的职业生涯中，我能够深入思考其中的一些问题并进行深入思考。

And so I think it can both be the dreaming blue skies approach and have implications for the future of humanity.

因此，我认为这既可以是梦想中的蓝天之路，也可以对人类的未来产生影响。

I think Earthrise is a very good example of that.

我认为《地出》就是一个很好的例子。

Looking back at the Earth as it rose over the moon in the Apollo missions initiated environmental movements.

回顾阿波罗任务中从月球升起的地球，引发了环保运动。

It really gave people a strong sense of connectivity on the Earth and kind of the limitations and evils of tribalism.

它确实给了人们一种强烈的地球联系感以及部落主义的局限性和罪恶感。

So it changed culture, right?

所以它改变了文化，对吗？

It changed civilization.

它改变了文明。

So I think we can do both those things.

所以我认为我们可以做这两件事。

You know?

你知道？

I mean, this, here we’re getting into theology and ethics and all of that, but maybe science, which is often seen as somehow separate from all of that, is really a very good teacher about how to live ethically.

我的意思是，我们在这里讨论神学和伦理学以及所有这些，但也许科学，通常被认为在某种程度上与所有这些分开，实际上是关于如何道德地生活的非常好的老师。

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

《The Joy of Why》是来自《Quanta》杂志的播客，《Quanta》杂志是一份由西蒙斯基金会支持的独立编辑出版物。

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 .

西蒙斯基金会的资助决定不会影响本播客或广达杂志的主题、嘉宾或其他编辑决定的选择。

The Joy of Why is produced by PRX Productions.

《为什么的喜悦》由 PRX Productions 制作。

The production team is Caitlin Faulds, Jade Abdul-Malik, Genevieve Sponsler, and Merritt Jacob.

制作团队包括 Caitlin Faulds、Jade Abdul-Malik、Genevieve Sponsler 和 Merritt Jacob。

The executive producer of PRX Productions is Jocelyn Gonzales.

PRX Productions 的执行制片人是乔斯林·冈萨雷斯 (Jocelyn Gonzales)。

Edwin Ochoa is our project manager.

埃德温·奥乔亚是我们的项目经理。

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

Quanta 杂志的 Simon Frantz 和 Samir Patel 在 Samuel Velasco、Simone Barr 和 Michael Kanyongolo 的支持下提供了编辑指导。

Samir Patel is Quanta’s editor-in-chief.

萨米尔·帕特尔 (Samir Patel) 是广达的主编。

The episode art is by Chanelle Nibbelink and our logo is by Jaki King and Kristina Armitage.

剧集艺术由 Chanelle Nibbelink 创作，我们的徽标由 Jaki King 和 Kristina Armitage 创作。

Special thanks to Garth Avery at the Cornell Broadcast Studio.

特别感谢康奈尔广播工作室的 Garth Avery。

I’m your host, Janna Levin.

我是你们的主持人，詹娜·莱文。

If you have any questions or comments, please email us at [email protected] .

如果您有任何问题或意见，请发送电子邮件至 [email protected]。

Thanks for listening!

感谢您的聆听！

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获取发送到您的电子邮件收件箱的最重要新闻的摘要

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《Quanta》杂志对评论进行审核，以促进知情、实质性、文明的对话。

Abusive, profane, self-promotional, misleading, incoherent or off-topic comments will be rejected.

辱骂、亵渎、自我推销、误导、语无伦次或偏离主题的评论将被拒绝。

Moderators are staffed during regular business hours (New York time) and can only accept comments written in English.

版主在正常工作时间（纽约时间）有工作人员，并且只能接受英文评论。