英國皇家天文學家馬丁·里斯訪談：宇宙、政治、新冠、地外生命、后人類物種等

Astronomer Royal Martin Rees discusses the most extraordinary aspects of his distinguished career, from black holes to billionaires in space and the prospects of life beyond Earth

英國皇家天文學家馬丁·里斯討論了他杰出職業(yè)生涯中的一些最非凡的方面，從黑洞到太空中的億萬富翁，以及對地球以外的生命的推測。

AS ASTRONOMER Royal, you have to assume Martin Rees isn’t in it for the money: ￡100 a year is the reward for advising the UK monarch on all matters astronomical.
It is just one of many hats Rees has worn, though – including president of both the Royal Astronomical Society and the Royal Society and, since 2005, as an appointed member of the UK’s House of Lords. His work as a government adviser and public face of science has come on the back of an equally distinguished career in cosmology stretching back more than half a century, encompassing seminal research on the nature of the big bang and black holes, extreme phenomena throughout the cosmos, the search for life elsewhere in the universe and, latterly, humanity’s own fate within it.

“英國皇家天文學家”這個頭銜，必須承認馬丁·里斯不是為了錢而獲得的：每年100英鎊的報酬 是為英國君主就所有天文問題提供建議的獎勵。不過，這只是里斯戴過的眾多頭銜之一——包括皇家天文學會主席和皇家學會主席，以及自2005年起成為英國上議院的成員。他作為政府顧問和科學家形象出現(xiàn)在公眾面前工作是在半個多世紀以來同樣杰出的研究宇宙學的職業(yè)生涯的背景下完成的，包括對大爆炸和黑洞本質的開創(chuàng)性研究，以及整個宇宙的極端現(xiàn)象，尋找宇宙其他地方的生命，以及以后人類在其中的命運。

Richard Webb: When you started out in cosmology, the idea that the universe began in a big bang wasn’t even accepted science. How have things changed in the past half-century?
Martin Rees: Amazingly. When I started research in the mid-1960s, the [late] astronomer Fred Hoyle was still advocating the idea of a steady state universe that had existed from everlasting to everlasting. Evidence for the big bang theory was very weak. The debate was settled in most people’s minds in 1964 when cosmic microwave background radiation was found – a relic of a hot, dense, early phase of the universe.
It was a good time to be starting research. obxts such as black holes and neutron stars were being found where Einstein’s general relativity was important, not just a tiny correction as it is in our solar system. At the same time, theorists like Roger Penrose were developing new techniques to solve Einstein’s equations, which was a big leap forward.

【1】理查德·韋伯：當你開始研究宇宙學時，宇宙起源于大爆炸的想法甚至沒有被科學接受。在過去的半個世紀里，情況發(fā)生了怎樣的變化？
馬丁·里斯：令人驚訝。當我在1960年代中期開始研究時，[已故的]天文學家Fred Hoyle仍在倡導一個從永恒存在到永恒的穩(wěn)態(tài)宇宙的想法。大爆炸理論的證據(jù)非常薄弱。1964年，當宇宙微波背景輻射被發(fā)現(xiàn)時，爭論在大多數(shù)人的頭腦中得到了解決——宇宙微波背景輻射是一個熾熱、密集的早期階段的遺跡。
這是開始研究的好時機。在愛因斯坦的廣義相對論的重要幫助下，科學家發(fā)現(xiàn)了黑洞和中子星等物體，而不僅僅是對我們太陽系中的微小修正。與此同時，像羅杰·彭羅斯這樣的理論家正在開發(fā)求解愛因斯坦方程的新技術，這是一個巨大的飛躍。

Is the big bang theory set in stone now?
As in all of science, every advance opens up new questions. We can understand the physics of the universe right back to when it was a microsecond old. That’s an amazing achievement. But why is the universe expanding the way it is? Why does it contain the mixture of atoms, radiation and dark matter that it does? And why did it have the kind of irregularities that resulted in it not remaining a uniform gas, but developing clusters of galaxies?
The answer to those questions lies before the first microsecond, when the entire universe was just the size of a tennis ball. As yet, we’ve got no experimental foothold on the very extreme physics involved.

【2】大爆炸理論現(xiàn)在已經(jīng)被確認了嗎？
與所有科學一樣，每一次進步都會帶來新的問題。我們可以從宇宙僅一微秒年齡的時候開始了解宇宙的物理性質。這是一項了不起的成就。但是為什么宇宙會以現(xiàn)在的方式膨脹呢？為什么它包含原子、輻射和暗物質的混合物？為什么它有那種不規(guī)則性，導致它沒有保持均勻的氣體，而是發(fā)展出星系團？
這些問題的答案存在于宇宙生命的第一微秒之前，那時整個宇宙只有網(wǎng)球那么大。到目前為止，我們在所涉及的非常極端的物理學上還沒有實驗立足點。

Clearly, our knowledge is incomplete. We know dark matter behaves like neutral particles in a swarm that don’t collide with each other. We notice about five times as much mass in that form as within atoms, and that allows us to get a good model of how galaxies form. What it is, we don’t know. But it is easy to envisage particles we haven’t discovered yet and that are harder to discover. There’s no reason why everything in the universe should shine.
Dark energy is telling us something we don’t understand about space itself. It’s saying that the vacuum itself has properties: it exerts a force that causes the universe to accelerate when you’d expect it to be decelerating through gravity’s pull. I think this is one of the big challenges related to the very, very early universe. With dark matter, I think there’s a reasonable hope, within the next 20 years, of making progress. With dark energy, I think it will be much longer.

【3】當宇宙的95%以我們無法解釋的形式出現(xiàn)時，我們能聲稱有任何理解嗎？也就是說，暗物質和暗能量？
顯然，我們的知識是不完整的。我們知道暗物質的行為就像一群不會相互碰撞的中性粒子。我們注意到這種形式的質量大約是原子內(nèi)部的五倍，這使我們能夠獲得一個很好的星系形成模型。它是什么，我們不知道。但是很容易想象我們還沒有發(fā)現(xiàn)的粒子，而這些粒子更難被發(fā)現(xiàn)。沒有理由宇宙中的一切東西都會發(fā)光。
暗能量告訴我們一些我們對空間本身不了解的事情。據(jù)說真空本身具有特性：它施加的力會導致宇宙加速，而你預計它會因重力的拉動而減速。我認為這是與非常非常早期的宇宙相關的重大挑戰(zhàn)之一。對于暗物質，我認為在未來 20 年內(nèi)取得進展是有合理希望的。而對暗能量的研究，我想需要更長時間。

Meanwhile, cosmology is increasingly embracing outlandish concepts such as the multiverse. Do you subscribe to that idea?
The multiverse comes from the theory of inflation, the best theory we have to explain why the universe is as large and uniform as it is now. It implies that it started off small enough that quantum fluctuations could have shaped the entire universe. One idea developed out of that, mainly by the cosmologist Andrei Linde, is eternal inflation, this idea that inflation might go on, producing many big bangs and many universes.
I was once at a panel discussion with Linde. Someone asked: would you bet your goldfish, your dog or your life on the multiverse? I said I was dealing with a dog level. Linde said he had spent 25 years on this theory, so he would almost bet his life. When asked his views at a later conference, [physics Nobel laureate] Steven Weinberg said he would happily bet Martin Rees’s dog and Andrei Linde’s life. But I think Andrei Linde, my dog and I will all be dead before it’s settled.

【4】與此同時，宇宙學越來越多地接受諸如多元宇宙之類的古怪概念。你同意這個想法嗎？
多元宇宙來自宇宙大爆炸理論，這是我們必須解釋為什么宇宙像現(xiàn)在這樣大而均勻的最佳理論。這意味著它開始時足夠小，以至于量子漲落可以塑造整個宇宙。主要由宇宙學家安德烈·林德（Andrei Linde）由此產(chǎn)生的一個想法是永恒的膨脹，這個想法認為膨脹可能會繼續(xù)，產(chǎn)生許多大爆炸和許多宇宙。
我曾經(jīng)和林德一起參加小組討論。有人問：你會把你的金魚、你的狗或你的生命賭在多元宇宙上嗎？我說我處理的是狗級別的。林德說，他在這個理論上花了25年時間，所以他幾乎賭上性命。在后來的一次會議上，當被問及他的觀點時，[諾貝爾物理學獎獲得者]史蒂文·溫伯格說，他很樂意以馬丁·里斯的狗和安德烈·林德的生命為賭注。但我認為安德烈·林德、我的狗和我都會在一切塵埃落定之前死去。

One idea associated with the multiverse is the anthropic principle – that certain features of the universe are just so because if they were any different, we wouldn’t exist to observe them. Isn’t that a bit of a cop-out?
One of the theories that would explain what happened under the extreme conditions of the big bang – string theory – suggests that empty space, the vacuum, is not simple. It’s got a microstructure, so there may be many different versions of it. Many big bangs might cool down in such a way that they ended up with a space with different conditions – a different strength of gravity or nuclear forces, a different mass of the electron. Only a subset of them would have had the properties that allowed life to emerge: for example, if gravity was very strong, obxts as big as us couldn’t exist without being crushed, so we need gravity to be important, but very weak. It’s all speculative, but what it’s saying is that reality is very complicated. There are many things we can’t predict: the weather a month ahead, for example, because of chaos theory. What we now regard as universal laws prevailing throughout the observable universe may, in the grander perspective of the multiverse, be just parochial bylaws applying in our cosmic patch. I don’t think you can call that a failure, just as you can’t blame weather forecasters for not giving an exact weather forecast.

【5】與多元宇宙相關的一個想法是人擇原理——宇宙的某些特征之所以如此，是因為如果它們有任何不同，我們就不會存在那里和觀察它們。這不是有點逃避嗎？
可以解釋大爆炸極端條件下發(fā)生的事情的理論之一——弦理論——表明空曠的空間，即真空，并不簡單。它有一個微觀結構，所以它可能有許多不同的版本。許多大爆炸可能會以這樣一種方式冷卻下來，最終形成一個具有不同條件的空間——不同的重力或核力強度，不同的電子質量。它們中只有一部分具有允許生命出現(xiàn)的特性：例如，如果重力非常強，那么像我們這樣大的物體不可能存在而不被壓碎，所以我們需要重力很重要，但是很弱。這都是推測性的，但它所說的現(xiàn)實非常復雜。有很多事情我們無法預測：例如，由于混沌理論，未來一個月的天氣。我們現(xiàn)在所認為的普遍存在于可觀測宇宙中的普遍規(guī)律，從多元宇宙的更宏大的角度來看，可能只是適用于我們宇宙補丁的狹隘章程。我認為你不能稱之為失敗，就像你不能責怪天氣預報員沒有給出準確的天氣預報一樣。

（圖：“地球升起”——在阿波羅 8 號登月任務上拍攝的標志性照片，美國國家航空航天局/比爾安德斯）

We have just seen the launch of the James Webb Space Telescope. What answers will it give us?
There are two important fields that it’s going to illuminate. One is the very early stages of galaxy formation. About a half a million years after the big bang, the universe enters a literal dark age until the first stars form and light it up again. We’d like to know whether these first stars form already in galactic structures or separately.
The second is the search for life in the universe. One of the most exciting developments in the past two decades has been the realisation that our solar system isn’t that special. If there were an Earth-like planet around one of the nearest stars, the Webb telescope might be able to take a crude spectrum of its light.
We might be able to use this to show evidence of life. It is probably just about the limit of what it can do. But if I look ahead 50 years, I would hope there will be large telescopes in space that will not merely detect light from extrasolar planets, but even a blurred picture revealing their surface features. It would be great if by 2068 – 100 years after the famous ‘Earthrise’ – we could display an image of another Earth.

【6】我們剛剛看到了詹姆斯韋伯太空望遠鏡的發(fā)射。它會給我們什么答案？
它將闡明兩個重要領域。一是星系形成的早期階段。大爆炸后大約50萬年，宇宙進入了真正的黑暗時代，直到第一顆恒星形成并再次點亮它。我們想知道這些第一顆恒星是在銀河結構中形成還是單獨形成。
二是在宇宙中尋找生命。在過去的二十年中，最令人興奮的發(fā)展之一是我們意識到我們的太陽系并不是那么特別。如果最近的一顆恒星周圍有一顆類地行星，韋伯望遠鏡或許能夠獲取其光的粗略光譜。
我們也許可以用它來展示生命的證據(jù)。這可能只是它可以做的極限。但如果我展望未來50年，我希望太空中會有大型望遠鏡，它們不僅能探測到來自太陽系外行星的光，甚至還能通過模糊的圖片來揭示它們的表面特征。如果到2068年——著名的“地球升起”100周年后——我們可以展示另一個地球的圖像，那就太好了。

Is not just life, but intelligent life, out there?
My view is that any intelligent life is unlikely to be a flesh-and-blood civilisation, but some exotic and possibly malfunctioning electronic entity. The timespan of our technological civilisation is just a few thousand years, and it could be less than another 1000 before it’s usurped by electronic entities. That is a very thin sliver of time, not only compared with the three and a half billion years of Darwinian evolution, but also to the billions of years that lie ahead. If there were another planet in the galaxy that had evolved like ours, it would be most unlikely we would catch it in this sliver.

【7】不只是生命，還有智慧生命，存在嗎？
我的觀點是，任何智能生命都不太可能是有血有肉的文明，而是某種奇異的、可能出現(xiàn)故障的電子實體。我們科技文明的時間跨度只有幾千年，再過1000年就被電子實體篡奪了。與達爾文進化的35億年的達爾文進化相比，與未來的數(shù)十億年相比，那是非常短的時間。如果銀河系中還有一顆像我們一樣進化的行星，我們不太可能在這塊碎片中捕捉到它。

Why stop at electronic organisms?
I completely agree. Since we are not the culmination of intelligence, we’ve got to be mindful that there could be aspects of reality of which we are unaware, which our brains couldn’t grasp. And so it could be that there is complexity and intelligence out there of a kind different from anything we can envisage.

【8】為什么要停留在電子有機體上？
我完全同意。由于我們不是智力的頂峰，我們必須注意現(xiàn)實中可能存在我們不知道的方面，而我們的大腦無法掌握這些方面。因此，可能存在與我們所能想象的任何事物不同的復雜性和智能性。

Talking of lifespans, two decades ago, you put the probability of our own extinction by 2100 at about 50 per cent.
I’ve since refined the arguments. I think the chance of something wiping out every human is small. On the other hand, I think the chance of some serious global setback to civilisation is quite high. This century is special: it’s the first in which one species has the power to determine the future of life on Earth. Of course, we started saying things like that when nuclear weapons were developed. But they are expensive, they need special facilities to build and we can monitor them. Now we have bio and cyber weapons and genetic modification, for example “gain of function” experiments to make a virus more virulent or transmissible. Threats that can cause a serious setback to our interconnected civilisation can be created in labs, or even in someone’s bedroom.

【9】談到壽命，二十年前，你認為我們自己到2100年滅絕的概率約為50%。
我已經(jīng)完善了這些論點。我認為某種東西消滅每個人的可能性很小。另一方面，我認為全球文明嚴重倒退的可能性很高。本世紀很特別：這是第一個物種有能力決定地球生命未來的世紀。當然，當核武器研制出來時，我們就開始這么說。但是它們很昂貴，需要特殊的設施來建造，我們可以監(jiān)控它們。現(xiàn)在我們有了生物和網(wǎng)絡武器以及基因改造，例如“功能獲得”實驗，以使病毒更具毒性或傳播性?？赡軐ξ覀兿嗷ヂ?lián)系的文明造成嚴重挫折的威脅可以在實驗室甚至某人的臥室中制造。

How should we be responding to these threats?
One thing we need is more resilience. Covid-19 has shown how dependent we are on networks: suppose the internet had failed during lockdown. We shouldn’t depend on supply chains where a single lix disrupts manufacturing, and we should keep a lot more slack in our hospitals.
But the ability of a few disaffected people to create a global catastrophe means we’re also going to have to contend with a tension between three things we want to preserve: freedom, privacy and security. We may be forced to accept more intrusive surveillance as the price we have to pay to minimise the risk of catastrophe.

【10】我們應該如何應對這些威脅？
我們需要的一件事是更有彈性。Covid-19顯示了我們對網(wǎng)絡的依賴程度：假設互聯(lián)網(wǎng)在封鎖期間出現(xiàn)故障。我們不應該依賴可能被單一環(huán)節(jié)擾亂生產(chǎn)的供應鏈，同時我們應該在醫(yī)院增加更多床位。
但少數(shù)心懷不滿的人制造全球災難的能力意味著我們也將不得不應對我們想要保護的三件事之間的緊張關系：自由、隱私和安全。我們可能被迫接受更具侵入性的監(jiān)視作為我們必須付出的代價，以盡量減少災難的風險。

（圖：英國劍橋郡伊利大教堂，伊萬·沃多文/阿拉米）

Climate change and biodiversity loss represent a different form of existential threat that we are failing to tackle…
The problem is that when something sudden like covid-19 happens, politicians and the public are immediately aware that they must do something about it, whereas, with these slow-burners, we are rather like the frog in the pot of water that is being heated – not taking action until it is too late to escape.

【11】氣候變化和生物多樣性喪失代表了我們未能解決的另一種形式的生存威脅……
問題是，當像covid-19這樣的突發(fā)事件發(fā)生時，政客和公眾會立即意識到他們必須對此采取措施，然而，有了這些慢熱的人，我們就像是鍋里溫水中的青蛙，正在被加熱——一直不采取行動，等想要逃跑時為時已晚。

Do you despair at our inability to think longer term?
There’s a paradox that strikes me whenever I visit Ely Cathedral, an amazing building just a few miles away from where we are sitting. It was built by masons as a structure that wasn’t to be finished in their lifetime, but which still inspires us 800 years later. We can’t think long term like they did. I think the reason is that those masons thought their grandchildren would live similar lives to them. Now, however, the pace of technological change means we don’t know enough about the preferences of people half a century in the future to be able to make confident plans. Although our horizons in space and time have hugely expanded, our capacity to do reliable long-term planning is less than it was in medi times.

【12】您對我們無法長期規(guī)劃感到絕望嗎？
每當我參觀伊利大教堂時，都會遇到一個悖論，這是一座離我們坐的地方只有幾英里遠的令人驚嘆的建筑。它是由泥瓦匠建造的，持續(xù)幾代人才能完成，但在800年后仍然激勵著我們。而我們卻不能像他們那樣長期規(guī)劃。我認為原因是那些泥瓦匠認為他們的孫子會過著與他們相似的生活。然而，現(xiàn)在技術變革的步伐意味著我們對未來半個世紀的人們的偏好還不夠了解，無法做出自信的計劃。盡管我們在空間和時間上的視野已經(jīng)大大擴展，但我們進行可靠的長期規(guī)劃的能力卻不如中世紀。

So meeting climate targets isn’t enough to plan for future generations?
Even if a country such as the UK meets its net-zero target by 2050, that is only a small contribution. What’s more important is what happens to the 4 billion people who will be in India or sub-Saharan Africa by 2050, and who are going to need more per-capita energy if they are to develop. If we can somehow enable them to leapfrog directly to clean energy, just as they’ve leapfrogged directly to smartphones having never had landlines, then that will be something which does more for the world than simply meeting our own targets.

【13】那么滿足氣候目標還不足以為子孫后代做長遠規(guī)劃嗎？
即使像英國這樣的國家到2050年實現(xiàn)凈零排放目標，這也只是很小的貢獻。更重要的是，到2050年，將在印度或撒哈拉以南非洲的40億人發(fā)生什么變化，如果他們要發(fā)展，他們將需要更多的人均能源。如果我們能夠以某種方式使他們能夠直接跨越到清潔能源，就像他們從沒有固定電話直接跨越到智能手機一樣，那么這將比簡單地實現(xiàn)我們自己的目標對世界更有幫助。

When you started out as a scientist, it was the middle of the space race. Now, we’re back there again. Is space the solution to our problems?
I think it’s a dangerous delusion to imply, as Elon Musk does, and as my late colleague Stephen Hawking did, that there could be mass migration to Mars to avoid Earth’s problems. Dealing with climate change on Earth is a doddle compared to terraforming Mars to make it habitable.

【14】當你開始成為一名科學家時，那是太空競賽的中間階段?，F(xiàn)在，我們又回到了那里。太空是解決我們問題的方法嗎？
我認為，正如埃隆馬斯克和我已故同事斯蒂芬霍金所做的那樣，暗示可能會有大規(guī)模遷移到火星以避免地球的問題，這是一種危險的錯覺。與改造火星使其適合居住相比，應對地球上的氣候變化是一件輕而易舉的事。

Should we be sending astronauts to space at all?
If I was from the US, I wouldn’t want my tax money to go to NASA’s space programme for human space flight. Miniaturisation and robotics are advancing fast, so the practical case for astronauts is getting weaker all the time.

【15】我們應該把宇航員送上太空嗎？
如果我來自美國，我不希望我的稅款用于NASA的載人太空飛行太空計劃。小型化和機器人技術正在快速發(fā)展，因此宇航員的實用價值一直在變?nèi)酢?/b>

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