Joseph Silk, "Back to the Moon: The Next Giant Leap for Humankind" (Princeton UP, 2022)

Welcome to the new Books Network. Hello everyone and welcome to another episode of the Princeton University Press Ideas podcast. A joint production of Princeton University Press and the new Books Network. I'm Mark Clovis and today I'm speaking with Joseph Silk off through the book Back to the Moon, the next giant leap for humankind. Hello, welcome to the new Books Network. Hello everybody. I was worried if you could start us off by telling our listeners something about yourself. Right, so I am a research scientist. I was previously a professor and now I'm retired from that and I just do research. And my research consists of the field of astrophysics trying to understand the origin of things we see in the universe, anything from stars to the universe itself. And that might mean such typical questions as what is the nature of the dark matter that's such an enormous part of our universe around us in all the galaxies we see and throughout space in fact. And why is the universe beginning to speed up its expansion? Another big question. Where did the universe come from? How did it begin? And even touching on such issues as are we alone in the universe? Are there other beings out there yet to be discovered on distant planets? So those are the themes I do. My background is that I began as an England as a student. I was at Cambridge University and there I got interested at the end of my stay there as a student in questions about the universe and went on to go to the US actually to Harvard to learn all about astronomy. And I did my thesis on the formation of the galaxies. And from then on I never really looked back and I stayed in this field of the distant universe really. And it was a great time actually because the knowledge horizon was expanding dramatically when I was a student. It's fascinating to hear that vast sweep of your focus in terms of your study, especially when I compare it to the book that you've written, which seems in some ways the opposite that you've taken this vast scale. And you've written a book now that's about our nearest celestial neighbor. I was very eager perhaps to explain what it was that led you to write this book and how it connects to what it is that you do. Well for a long time I worked on the Hubble Space Telescope. Maybe you remember but when it was first launched it had a severe optics problem. And so it had to be redesigned with a special corrector lens. I wasn't directly involved in that process but it caught certainly quite attention. And then a few years later it was time to upgrade the telescope and fit it with a new camera. And that's something I did get involved in listening to many discussions on advisory committees about how best to design this new system, this new lens and camera. And that worked very successfully. It led to many of the most beautiful images that we see now are taken with the Hubble Space Telescope. So that was my background and then many years later the newest telescope is launched, the successor to Hubble. And I'm following that with great interest to see the reproduction of even more beautiful images of the distant universe. What is the most beautiful thing to see? So how exactly does all these wonderful images and all this new knowledge that we're gaining contribute to your call for us to return to the moon? In one sense that all of these telescopes that we're launching, all these machines that we're sending out to explore to study the universe are doing the job for us. Why do you think do they correct you that we should then return to the moon? So here's the problem. The telescopes you've had in the past are not very large. For example, the Hubble is a couple of meters across. The web is some six meters across. We can build bigger telescopes on the ground on high mountains. Right now the largest telescope where it's under construction in Chile and the Atacama mountains is some 39 meters across huge size. The bigger the diameter of the telescope, the more light it collects. But we've run into a frustrating time because we're finding that all our current telescopes are producing more questions than answers. We still haven't converged on a full understanding of the beginning of the universe, where it came from, what was the origin of the Big Bang. Also, we're seeing lots of distant planets and we'd love to know if conditions are suitable for life and so far with our current telescopes we can only scratch the surface of this problem because we just don't have the light gathering power to look far away and deep into the universe. So the reason I got into the moon is that that's a place where you can build big telescopes, huge telescopes. Why? Well, the gravity is much lower. There are no winds, nothing will blow the telescopes down. So you're not really limited by size. And what's more, there's no atmosphere on the moon, there's no ionosphere, which traps radio waves. So you can build telescopes that receive ordinary light, that receive radio waves of unprecedented size and with far superior conditions for reception of this and signals. So I really think that our limitation so far is simply light gathering power or for radio telescopes radio wave gathering power. And the only thing that can improve this is sheer size and the moon gives us a stable platform. There are no significant moonquakes where we can build big things and therefore see much further away, much deeper into the universe. That's the goal. And as you explain, that's just one goal. It serves in a sense as a just one example as to how the moon can vastly expand our understanding of the universe. And in your book, you explain all the things that we could potentially learn or that or questions that the moon could potentially answer for us if we returned there and basically make a presence there permanent. I was very think could maybe talk a bit about some of these other motivations. And in particular, how the by going back to the moon and studying the formation of the moon, we can then learn things about our own planet. Well, we certainly will when we get to the moon learn how to preserve a pristine environment, something with notoriously fail to do on the earth so far. So that's one lesson for the future, I hope. But in the meantime, there are many activities we will do on the moon that will enlighten us greatly and satisfy many of our needs and wishes and desires that we have on the earth. To give you one simply of the most pressing needs that people have now, it is as mundane as tourism. Many people wish to go to more exotic places and there's nothing more exotic. You can imagine than a vacation on the moon. And this is something that will happen in 20, 30, 40 years. We will be preparing the moon for tourism now already the long cues of people signing up for trips to the moon. One would go in something like one of the starryx space craft and there are others being planned on a tour that would initially circle the moon several times and come back to earth. One could buy tickets for that already. But in the longer term, there will be landing on the moon. There will be building resorts hotel resorts on the moon and there will be endless tourism activities. Now at the beginning, I'm sure this will be for the super rich. I mean, already a ticket for an orbit around the moon costs some, I think the price, but ticket may be up to 50 million or something dollars. And that clearly is not for the average person, but in the long term, I feel confident there will be mass transport to the moon. Just as happened with the aviation industry, think back to the early years of a year. aviation transport tickets were incredibly higher first not for the average person but look how they've come down Now with the budget airlines and all that anybody can really fly Around the world for their holidays if they so wish and I imagine that'll be the case Indicates time for trips to the moon. So that's one of the great things will have an amazing place to Which will be preserved But to see new things that we can't possibly imagine on the earth That's one aspect then there's a commercial aspect to One of the great drivers on the moon which will help the earth greatly is the fact that on the earth we're running out of rare elements For example one of the rare earths European is forecast to have a thousand year supply on the earth in terms of being mined now That may strike you as a very long time But a thousand years is nothing compared to the ages we're talking about we hope that the earth will have a flourishing Civilization for if we don't sort of mess things up and we need a larger supply I mean in time and in not so very long actually that as the rare earths become rarer And more difficult to extract by mining on the earth the prices will zoom up So it will become a very attractive activity for mining companies to explore places on the moon whether or deposits of rare earths and Mind them and bring them back to earth and I should say but there is enormously more Rare earth material and other rare elements stocks of this on the moon that on the earth People estimate thousands of times more or more and that's simply because the moon has been bombarded Billions of years by asteroids depositing Their materials on the surface of the moon so there are deposits of many rare elements stuff which on the earth would Possibly when approaching the earth these asteroids would have burnt up at the atmosphere And so we would not have such reserves coming to us from space our reserves are being Plenished and what's more it's even highly toxic to mine some of these materials so interestingly enough in many countries So this activity is really very limited because of the of the dangerous nature of the All of the side products of the mining on the moon. There's no problem whatsoever because all the debris the rare material Can be shipped into the sun and the sun will burn all up. It's the most important incinerator of garbage You can possibly imagine a miseffective one and because of the gravity on the moon the launching spacecraft to the sun will not be difficult So I mean that that's the sort of future whereby the earth will benefit and Moon the moon will provide a key to the future Corve your book is constructed around your Description of how when we get to the moon again that we can use it to better understand our past and we're not talking about Historical discoveries of the Apollo landings. We're talking about the very Origin of of of the universe and life itself. I was worried you could perhaps elaborate a bit upon what you described earlier in terms of how getting to the moon Benefits are study of the of the origins of the earth the origins of the universe and how it is we can do things on the moon that we can't possibly do on earth to understand these things the moon formed some Billions of years ago not too long after the earth formed by we think The collision of a giant asteroid actually more than asteroid really something more or less the size of Mars with the earth and this huge catastrophic impact There was a giant splash of debris that later condensed around the earth to form the moon and we Can tell that something like this most likely happened from comparing the composition of the moon with that of the earth that It may be related to impacts that we do record on the earth that in terms of composition Now this is just a theory of course but only by going to the moon and digging deep into the moon and exploring Its structure and how the mantle of the moon was formed the learn all of that we'll be able to reconstruct its history So we'll certainly be able to understand far more about the About how the solar system of the earth originated by studying the moon So it'll be a key to a deeper understanding of The earth's formation longer go so that's one of the driving things for scientists and perhaps the other Activity that I foresee is once we Can explore the far side of the moon that's an area that's Completely blocked from the earth just as we don't see the far side from the earth if you're on the far side You don't see the earth. Why is that such a good thing if you're on the far side? Well, if you want to study radio waves from the distant universe then the earth is a huge source of Emission television emission cell phone emission radar emission all of this which could give you a terrible background and Distort any signal you would get by looking deep into the universe or going to the far side is a wonderful place to do radio astronomy and It's not very difficult with our current technology to build huge radio telescopes on the moon and we would want to do this by going to the far side and One could do much of this construction by bringing some material from the earth and perhaps constructing much of it locally there and With this we could look far into the universe because we'd be looking for radio waves That have come from far far in the past and have been their wavelengths have been greatly stretched out by the Expanded universe which means we'd be looking at very very low frequencies and can only access these Again really from the far side of the moon because on the earth Arionosphere and all the local radio noise would make it impossible So that's how the moon will take us To the beginning of the universe we able to look at these radio waves that were coming in space from Far before the first galaxies formed would be studying our beginnings basically and that that that that's a great motivation for Exploring the moon and doing some science at astronomy when we get there And it's not just exploring the origins of the universe that we can do with Better access to radio waves on the moon you also talk about how it can benefit the study of life In the universe and answer one of the you know largest questions we have which is whether or not we're alone So are we alone indeed? You know people have made the argument that our earth is not very old compared to the Age of the universe really we're about four and a half billion years old, but most stars around us are Much older maybe even twice as old and this means that their planets around all those stars And we know that most stars have lots of other planets We are older far older than we are now our civilization on the earth is only you know in terms of Modern technologies only a few centuries old Imagine a civilization that had thousands millions of years to evolve We can't even begin to dream of its power in terms of exploration and of knowledge et cetera and this of course There's some chance it had destroyed itself along the way That we don't know The risks of that really how how likely that is or not we certainly have the power now on the earth to destroy civilization on the earth For example by nuclear wars that sort of thing But even if that Potestry would have happened on some distant planet Then you know life is very capable of rebirthing really and one could imagine after again It might take a long time and to thousands of years But one has enormous amounts of time to to redesign to grow new technology to even greater Strelson before and one would hope that when cycles like that happen Knowledge is gained and one would avoid some of these terrible Antastrophes that might be human made That would have led to ecological disasters of course. There are natural catastrophes such as giant asteroids slamming into the planet and effectively Destroying all life on the planet or the the host star of the planet exploding and that would burn the planet to a cinder Well, that's a lot of then you'd want to go to another planet further from the start. But there are so many planets that we surely would expect to find traces of life somewhere. Now the problem is that because of all these potential catastrophes and the other thing I should mention is that we have no idea how difficult it is to begin life and a planet like the Earth, it might be a very rare and difficult thing to have done. We know it worked once, that's for sure, we hear. So the only response to searching for life then is to have many, many targets. What you want to do is find planets, distant planets that are near stars like the Sun and don't have a giant methane at rich atmospheres like Jupiter but have more oxygen-rich atmospheres like the Earth. That means that it has to be the right distance from the Earth's planet, not too hot, not too cold. And we know already there must be vast numbers of these exoplanets as we call them, billions of them in the universe, trouble is most of very far away. So that brings us back to looking for them and for that we need huge telescopes because you just have to look farther and farther away, not just in our neighbourhood a few light years away but hundreds or thousands of light years to have a chance of picking up many, many potential life-bearing planets and with luck, you know, a small number of these might have livable atmospheres and seasons and conditions that are conducive to life. And if we have enough of these planets, which is possible, we might even find signs of life. So that is the hope and it seems clear that only by building huge telescopes can you get there and we simply can't build them on the Earth. We could impressively do this in space but it's incredibly expensive to imagine doing this in space whereas the Moon is a whole different kettle of fish. We're going to the Moon. We're going to build telescopes there. It's part of our future strategy. The funding is there for some of this. It's a logical thing to do to build bigger and bigger telescopes on the Moon that will enable our search for distant life and try to answer this question of, you know, are we alone in the universe? Now there are some who argue that, you know, doing this is a waste of resources that this is an argument that goes back to the 1960s where, you know, why should we spend this money exploring things like the, you know, whether or not there's life in the universe when we have to deal with life on our own planet. And yet you then, in your book, you go on to explain how getting to the Moon and, you know, studying the Moon and, for lack of better word, exploiting the Moon is something that can benefit humanity, that can actually aid our ability to survive, you know, into the future. I was wondering if you could perhaps elaborate a bit upon that about how the, as you demonstrate, as you explained, the investment in resources in getting to the Moon will have a beneficial return for us here on this planet. Well, first of all, let's get this right. It really is an expensive actually. What is expensive is getting to the Moon and developing infrastructures on the Moon. And that decision has been taken already. Yeah, major space agencies, not just NASA, but also in China and Russia. I determined to do this and there are commercial benefits too. And my argument is simply that for a tiny fraction of this cost of building the infrastructure on the Moon, one could build giant telescopes. It would just be a few percent of the cost. And with that one could do amazing science. Now you may think, well, you know, that's still billions of dollars most likely, but it's a tiny fraction of a total. And if I look back at what we've done before in space, I can see that these amazing images which we obtained with the Hubble telescope, everyone has seen those, they're incredible things. They really are. They give us a psychological lift when we look at them, many people, they have things of beauty. Well, the cost of the Hubble telescope was just a few percent of the cost of the space shuttle, which took us to the space station and that as well. So we had this amazing project to build space shuttles now over and the space station still ongoing. And the telescope's a tiny byproduct of that in terms of cost. And we did that because it was clear that one needed to go more than the commercial route with the space station, but to do things that would uplift humanity. And the same thing is now true for the moon, even more so I would say because we have these huge commercial targets which many nations are interested in, which we have yet to regulate, but we hopefully will achieve all of this for the moon. And by just devoting a tiny fraction of the cost of pursuing all of these and maybe even turning some of the profits into use for science, can we, will we be able to develop telescopes and so forth through these amazing things. And this will be, I think, a great boost for us, for humanity to answer these amazing questions, where have we come from? Are we alone in the universe? I think we've never posed such important questions until recently, we've begun to realize, you know, the last century how what a small part of the universe we are, we want to know more, we want to understand more about where we came from. And I think we can best do this by building structures, telescopes like structures on the moon as a small part of our lunar adventure. So that I see as a immensely valuable contribution to humanity, just as, you know, poetry is or literature is, you know, we're not going to ban those for human activity because we'll say, oh, it's much more important to, you know, to manufacture shoes or something. We have to do other things, we do do other things. And it's important for our, you know, for our vision of the future, for our psychology, for our philosophy, for many things. And to me, the moon offers a similar vision, similar vision for the future. And it's not just a vision that is necessarily abstract and long term. You conclude your book by talking about how the effort to get to the moon might aid us in this planet by contributing to international collaboration. I was wondering if you could perhaps talk about that process, you kind of how it is that, you know, how we're trying to arbitrate the competition to get to the moon now. And also how you see us benefiting from, you know, that joint effort or that competitive effort going forward in terms of how that affects us here on this planet. Well, the one issue that we have that's driving much of this exploration of the moon, other commercial benefits to be had. What we're already doing and planning and many countries revolved in this is surveying the moon for deposits of rare earths because we know they're going to be incredibly important in the future as they run out on the earth for all of, you know, our television screens, our scanners, our energy producing devices such as women, all that, all of this stuff relies on having critical contributions from rare earth elements. So all of this is clear that we need to look for our resources that will come from the moon. So I see that as the major upside and that will benefit us greatly, but the danger is the following that right now there are just perhaps two or three space agencies that have the power, the ability to send large spacecraft to the moon. The US is ahead at the moment with the recent launch of NASA's larger replacement for Saturn 5 of the Apollo era. Now the worry I have is that will it be first come first served on the moon? Will the first humans to land on the moon stake out territory? Will they lay claim? Then the others will come in, other countries may come in later and dispute those claims. Will exploration of the moon be a return to the Wild West? I really hope not. That will be terrible if that would happen and we need international collaboration. Now this can work, it did work for exploration of the Antarctic. We have an Antarctic treaty that really does control commercial activity and mining out for all sorts of things at the South Pole. That seems to have worked. But frankly for the Antarctic, that's small. The commercial gains there are tiny compared to what is available will be potentially available on the moon. So the gains are much higher potentially and it's going to be correspondingly harder to reach international records. Now fortunately there is one outer space treaty that was passed the United Nations some decades ago with more than 100 signatures to it and that does lay down some very interesting rules that these countries signed up to. One of them is no military activity on the moon. Another one is no pollution on the moon and so on. The problem is although many countries signed but not all yet we have to revisit this. There is no obvious means of enforcement of this treaty. What if there are crimes on the moon? How do you control that? What if territorial disputes? What if someone says I want this patch? I'm going to take it from you because as a certain rare earth I need for critical reasons back on the earth you know to make some medical instruments but make critical for saving thousands of lives. I'm going to have a better claim to this than you. So how do we enforce this? Well I really don't know at the moment. We are talking now of having police forces on the moon. Again perhaps the NASA and the US have announced some thing along these lines already. Other countries I'm sure will not be far behind. So we have to be optimistic and hope that long before we get to the serious commercial exploitation stage on the moon will come to an enforceable international agreements that will divide the moon up areas of the moon that different countries need in a way that's peaceful and legal and controllable. I hope that happens. I think it will happen because we're beginning to realize with all the discussion of global warming what mistakes were previously made on the earth. I don't think we want to repeat those on the moon. So let's hope that we come to our senses and develop a legal framework for lunar exploitation. We appreciate the time you've taken to speak with us but before we go could you tell us what you're working on now? So my current interests are what is the dark matter in the universe. So it's a it's a very bizarre fact but something like 95% of the universe, all the stuff in the universe is invisible. I mean we see lots of stars obviously and with radio telescopes we can see gas clouds. So all this stuff we see in the universe we see even what we call nebulae hot nebulae meeting x-rays and ultraviolet like amazing things are seen in our space telescopes but 95% is missing. Now we know this because we can use the motions of the stars to test gravity locally in different places in the galaxy other galaxies and we just realize that 95% simply is not a counter for but the stars we see. So what is that stuff? So I'm working on trying to elucidate what this dark matter might be and I should say that right now we have a couple of candidates but it's a little bit like you know looking in the dark when you've lost your car keys where do you look? Well you go to the nearest street light okay and look around there because maybe you drop them when you're walking home elsewhere it's impossible. It's a bit like that unfortunately with the dark matter we have some favorite candidates for what the dark matter might be but right now we can test for those but there are so many other possibilities. We're very good actually we scientists that inventing new ideas that could be possible great candidates for dark matter and then we think of ways to test them they turn out to be very difficult and they will happen someday no doubt but in many years time. So it's a never ending process searching for the dark matter a key component of the universe and that is what's keeping me busy at the moment to think of you know exotic candidates for the dark matter which so far we simply haven't found despite intense searches for the post two decades building bigger and bigger machines that look are designed to look for invisible matter because even this invisible matter has very feeble interactions with no matter it should occasionally blow in the dark if I have enough material to search for it and put it deep underground where it's very dark and very clean and shielded from cosmic rays that's the sort of thing we're doing but so far nothing we have to continue looking because it's one of our greatest problems in astronomy to find the dominant component of mass in the universe. Well I wish you the best of lung of luck in terms of finding the answer to that question sounds like an enormous question or one that it definitely is you know hopefully we can finance through someday. I really hope so and I'm confident we'll get more things but whether it's in 10 years or 50 years we simply can't say it about it. Well thank you very much for taking some time to speak with us Joe I hope you have a wonderful day. Thank you so much Mark.