Sean Carroll's Mindscape: Science, Society, Philosophy, Culture, Arts, and Ideas - 131 | Avi Loeb on Taking Aliens Seriously

Episode Date: January 25, 2021

The possible existence of technologically advanced extraterrestrial civilizations — not just alien microbes, but cultures as advanced (or much more) than our own — is one of the most provocative questions in modern science. So provocative that it's difficult to talk about the idea in a rational, dispassionate way; there are those who loudly insist that the probability of advanced alien cultures existing is essentially one, even without direct evidence, and others are so exhausted by overblown claims in popular media that they want to squelch any such talk. Astronomer Avi Loeb thinks we should be taking this possibility seriously, so much so that he suggested that the recent interstellar interloper `Oumuamua might be a spaceship built by aliens. That got him in a lot of trouble. We talk about the trouble, about `Oumuamua, and the attitude scientists should take toward provocative ideas. Support Mindscape on Patreon. Abraham (Avi) Loeb received his Ph.D. in plasma physics from the Hebrew University of Jerusalem. He is currently the Frank B. Baird Jr. professor of science at Harvard University. He served as the Chair of Harvard's Astronomy department from 2011-2020. He is Director of the Institute for Theory and Computation of the Harvard-Smithsonian Center for Astrophysics, and Founding Director of Harvard's Black Hole Initiative. He is chair of the Advisory Committee for the Breakthrough Starshot Initiative. His new book is Extraterrestrial: The First Sign of Intelligent Life Beyond Earth. Harvard Astronomy web page Center for Astrophysics web page Wikipedia

Hey, everyone, it's Cal Penn. I'm inviting you to join the best-sounding book club you've ever heard with my podcast, Earsay, the Audible and I-Heart Audio Book Club. Every episode, I nerd out with amazing guests and dive into the best new audiobooks available on Audible. It's the book club for your ears. Listen to Earsay, the Audible and I-Heart Audio Book Club. On the I-Heart Radio app or wherever you get your podcasts. Exema's Unrelenting, Itch and Rash.

If you know the feeling, you should know the facts. The eczema medication you're taking may not be right for you. Visit MyRodtruth.com and talk to your dermatologist about your symptoms and treatment options. Hello, everyone, and welcome to the Mindscape Podcast. I'm your host, Sean Carroll. Some of you may remember back in October 2017, astronomers announced they had discovered an interstellar interloper in our solar system. There was an object, which they dubbed Amuamua, which was flying through our solar system.

It was much like a comet, but comets come from the outer solar system. They're in orbit around the sun very gently, and then something knocks them out of their orbit, so they dive in closer to the sun and we can see them. Amuamuwa, by contrast, was moving so fast that it was clearly not bound to the sun gravitationally. It came from way beyond the solar system, and after it zoomed by the sun, it's going to return back to interstellar space. So of course, astronomers are very excited by this. This is the first ever interstellar object in our neighborhood that we could see up close and personally. And many of them analyzed it. They wrote papers.

One such paper came out a year later by Avi Loeb, who was a professor at the Harvard-Smithsonian Center for Astrophysics, and Shmuel Biali, who was a postdoc at Harvard also. And it had the dry title of, could solar radiation pressure explain Amuamua's peculiar acceleration? And they go through and they do calculations and all these things. Near the end of that paper, there's one little paragraph which offhandedly they say, You know, it's possible Muamua is not a rock. It's possible that it's not just a naturally occurring object at all, but is in fact constructed by an advanced technological civilization outside of our solar system,

and it was targeted to go near the sun, perhaps with a solar sail or something like that. Again, one little paragraph, they didn't make a big deal out of it. But guess what? The world made a big deal out of it. This was discovered by people on the Internet, and suddenly Harvard scientists suggesting alien presence here in the solar system, right? So when that happens, you know, you have to understand when scientists think about different hypotheses for explaining the world,

they're very ready to explore all sorts of different possibilities. Just because they say that a possibility is conceivable, doesn't mean they think that it's likely you should get excited about it, right? We're going to put all the hypotheses on the table and then decide what we want. But given all this pressure, the sort of different things you could do,

you could say, well, oh, sorry, you know, don't take me too seriously. We didn't really mean it, et cetera. Avi Loeb in particular decided to go the other way. He doubled down. He said, no, no, no. This really is possible. We should really take this seriously

and got an enormous amount of criticism for that. Many other astronomers and many people in the media said that's not a good hypothesis. It does not fit the data. And they offered reasonable reasons to say that. So I'm not going to personally judge whether it is likely that a muamua was or was not an alien artifact.

We'll talk about that in this podcast interview with Avi Loeb. But I think that there are more important things that we're talking about. So one thing we're talking about is a muamua. Okay, we're going to talk about whether or not it is reasonable to think that this is an alien artifact or is it something else, right? Is it, you know, a rock or a comet or whatever? The second thing we're going to talk about is what is the attitude we should have toward more dramatic ideas, okay?

So should you hide them? Should you put them front and center? Should you talk about them to other professional scientists but hide them from the public? What should you do? The third thing we're going to talk about is the general idea of alien civilization. Should we be looking for them? Are they likely to be out there? What should humanity,

attitude B toward this idea that we are not alone in our nearby universe. And finally, we're going to talk about the nature of science as it is being done right now. We talked a little bit about this in last week's podcast with Frank Wilczak, where Frank offered the opinion that a lot of his theoretical physicist friends had wandered a little bit away from data. Avi Lube has similar opinions. You know, Avi's been a great, extremely respected and successful theoretical astrophysicist for a long time. He's also not afraid of poking the hornet's nest now and then. So Avi has very strong opinions about how science should be done, how it is being done, and we have a wonderful conversation about that. So whatever we might

eventually decide about the nature of this particular thing that flew through the solar system, I'm entirely on the side of the idea that we should explore the dramatic ideas and we should take them seriously. And if they're wrong, if we have good reason to believe that they're very unlikely, we can discard them and get on with our lives. But as much as there is a bias towards shiny objects, right? We're saying, ooh, this is a cool idea. Let's think about this. There's a countervailing bias, especially among professional scientists, which say, look,

we're bombarded with absurd scientific nonsense in the popular media all the time. It's our duty to stamp it out. And therefore, we should not even give any attention to these wilder ideas. But I think we should be honest about how difficult it is to really draw the distinction between an interesting, crazy idea that is worth pursuing. and something you should be dismissed out of hand. So that's one of the issues very, very much on the table for this conversation. I think you'll like it.

Let's go. Avila, welcome to the Minescape Podcast. Thank you for having me. So we're going to get into some details, obviously. You talk a lot in your book about this visitor we had from interstellar space, Amuamua. But I thought it would be very useful to sort of lay the groundwork by letting the audience know a little bit about what sort of background beliefs, professional physicists,

and astronomers bring to this kind of thing. So just to let people know, would you agree with me that most professional astronomers or astrophysicists spend approximately zero time thinking about alien life elsewhere in the universe? Yes, I agree, and that's unfortunate. Yeah. So, but you had, even before this recent thing, you had started becoming interested in it. Right.

Actually, I worked mostly on cosmology, on the first generation of stars in the universe, and on black holes. But in studying cosmology, one of the interesting frontiers that I helped develop was imaging hydrogen in the infant universe based on the very faint radio emission at 21-scentimeter wavelength that it produces. And for that purpose, there were a number of observatories constructed on Earth whose goal was to detect this low-frequency radio emission. from the early universe.

And then in 2007, during a lunch, I joked with Matthias Zaldaraga about the fact that, you know, the biggest obstacle to making these observations is radio interference from radio stations and TV stations on Earth because they operated similar frequencies. And so if that poses a challenge,

why wouldn't the same observatories be used to eavesdrop on signals from alien civilizations that are produced just by leakage of radio and TV broadcast. And then we went, so Mathias said, why don't we check the numbers? We checked the numbers and we found that out to distances of tens of light years, we should be able with existing observatories targeting cosmology.

We should be able to detect the radio signals from civilizations like ours. And of course, we started transmitting about a century ago. And that's an interesting coincidence that we can detect things out to the distance that our light was traveled in the meantime. And so we might hear a response from those distances if there is anyone out there. Well, that's the thing. I mean, I think that part of what I want to get down here is, you know, thinking like a good basie and what our priors should be, what our expectations. are. So I know a lot of this is old ground, but let's talk about what we expect. I mean,

there's the Drake equation, there's the Fermi paradox, all that stuff. In your mind, do you think that life is ubiquitous throughout our galaxy, or is it rare? And how often do you think it might be intelligent or otherwise? Or is it just one of these things we have no idea? Right. Well, science is about evidence. That's one thing that Galileo taught us, that, you know, you can have beautiful philosophical ideas that we are at the center of the universe, that the sun moves around the earth. Aristotle was a very wise person, but he was wrong. And Galileo realized that and said to philosophers, look through my telescope and you will figure it out as well. And they said, no, we know the answer. The sun moves around the earth and they put him in house arrest. That didn't

change the fact that the earth moves around the sun. So the bottom line is prejudice should not guide us. evidence should. And we should, evidence or facts are those things that do not go away, irrespective of what we think. And that's what science could be all about, collecting evidence without prejudice. Now, one piece of evidence that we collected recently,

actually, this year is that sun-like stars have a planet of the size of the Earth in their habitable zone, roughly half of, in half of the cases. You know, and that means that the Earth sun system is very common. You know, there are billions of such systems within the Milky Way galaxy, and you roll the dice of life so many times, it's very likely that we are not special, you know.

And one of the big questions asked by Fermi, Enrico Fermi, during a lunch as well in Los Alam, about 70 years ago, was, you know, if there is life out there, where is everybody? Why don't we hear from them? Now, to me, that's not a serious concern because, you know, when a pedestrian goes on a sidewalk, the pedestrian doesn't check every ant that is under his or her feet, you know, And we might be so common that we are of no interest to anyone. And moreover, we might not be smart enough to figure out that there are signals out there. Our instruments may not be sensitive enough.

We are not using sophisticated enough artificial intelligence to analyze our data. And so it's just like having a fishing net that has too big of holes in it so that the fish go through the holes. And so the fact that we can't detect them and that they don't show up on our planet, I don't think it makes any difference. We just need to search with more sensitivity. If you look at the gravitational wave search, for example, LIGO, for many years, LIGO did not detect anything. And then in 2015, it reached a threshold sensitivity,

and suddenly there was a flood of events. and by now we have more than 50 events and the Nobel Prize was given for the first one of Black Hole mergers. And it just shows that once you reach a threshold sensitivity, you can detect a lot of signals, but before you do that, you detect nothing. Yeah, you know, I have sort of conflicting impulses

pulling me in different directions here. On the one hand, let's go with the one hand first. The version of the Fermi paradox, the idea that there could be so many civil out there, why haven't we heard them yet? The version that I've always found most compelling is the von Neumann replicator version, where John von Neumann suggested that you could imagine building a machine that would go out into the universe, stop by different solar systems, replicate itself, and then send out

multiple copies of itself. And if this happened even once in the history of the galaxy, you know, the galaxy doesn't take that long to just fill up with these replicated machines. So that's the kind of thing you might think would be easy to find here in the solar system. Do you put any credence in that kind of argument? Well, it turns out that it's not so easy to find because, you know, right now with the PanStar survey, we can detect objects of order 100 meters at the distance of order the earth's sun separation because we monitor the sky with high enough sensitivity.

We couldn't have done that before. And that's why the first interstellar object was discovered. in 2017. Bigger objects are more rare and we have to wait longer before one of them crosses these distances so we can see it.

And so it depends how big these phoenomen objects are. And if there are of other tens of meters or less, then we would have a hard time seeing

them. If they move very fast also astronomers would dismiss them as astronomical sources because they move too fast across our sky. Most of the time we look for rocks within the solar system that move at tens of kilometers per second. If something would move at the speed of light across our sky, I can guarantee that no astronomer will pay serious attention to it. Right. And so you think that maybe we are surrounded by at least some density of these replicating machines. It's possible we just haven't noticed them yet. Yeah, and I think what we should do is develop better and more sensitive instruments and analyze the data without prejudice. I always remember when I was a postdoc, the field of gravitational lensing became very popular. And it turned out that

gravitational lenses were discovered decades earlier. And if you go through the astrophysicism, journal at images of clusters of galaxies, those images included giant arcs that were not interpreted. Nobody paid attention to them. People said, oh, maybe it's cut at light. We don't know what it is. And so only when the field became popular, suddenly people realized, oh, you know, these ancient images included already data that indicates that gravitational lensing takes place. And I think it requires us to be open-minded, attentive to a normal-minded, attentive to a normal

The most important thing is to pay attention to anomalies and not shove them under the rug of conservatism. Because most of the time what people say, oh, there is something unusual. Let's not tell anyone. Let's just say, well, you know, it's just noise or something. Instead, as scientists, we should recognize that breakthroughs and discoveries occur only when you pay attention to anomalies. If you are not open to wonderful things, to new things, you will never discover. of them. And so I think it's a self-fulfilling prophecy by the scientific mainstream to basically say, we don't want to consider anomalies. We don't want to look at extraterrestrial

civilizations, the possibility that they might exist. And with that state of mind, obviously we will never find evidence for those things. But I think it's arrogant on our behalf to believe that we are special and unique. You know, my daughters, when they were infants, they tended to think that they're at the center of the world, that everything focuses on them. Then they went to the street and saw other kids, and they got a better perspective. So the only way for us to mature as a civilization is to find evidence that we are not alone. And only then people will get the right perspective. Now, if scientists refuse to look through the telescopes with that notion in mind, then we will never find it. It's just like the philosophers in the days of Galileo.

I don't think we learn the lesson. Exercise and working out are really important, but if you're like me, it can be problematic sometimes to stay motivated or to try to do something a little bit more, to push yourself a little bit. That's why it's so helpful to have an instructor or a trainer. But at home, that's hard to do. Fortunately, Peloton is to the rescue. With world-class instructors curated music and endless fitness variety, Peloton has created an

unmatched fitness experience to help keep you motivated and focused workout after workout. And Peloton isn't just game-changing cardio. You can add a strength class to your ride, where combine cardio and strength in one workout with bike boot camp to get a total body fitness experience. From beginner programs to Tabata intervals, Peloton meets you at every step in your fitness journey. As you progress, choose from a wide range of cycling classes that meet your level and keep you challenged every time you clip in. So get started on your Peloton journey today and download the Peloton app before January 31st, 2021 for a two-month free trial. That's two free months when you download the Peloton app on your phone, tablet, or smart TV. This is a huge set of questions here

that I do want to get to later in the podcast, but it would distract us from extraterrestrial life and intelligent civilization. So let's footnote that for right now, bracket it off. Because I want to I talk about this idea of the probes one more time because there's the idea of probes that just sort of zip by and we can't notice them. But it's also someone pointed out to me that if you think about listening for communications from extraterrestrials by radio waves or something like that, that sounds like a huge long shot just because you need to be listening to them at exactly the right time that they would be. giving out those radio waves and maybe most civilizations are not as wasteful as us just beaming stuff out into the sky. It might be better to imagine that if other civilizations wanted to make contact with us, they would send a kind of probe to come to the solar system and stay here, either in orbit around somewhere or landing on a planet, you're like a monolith kind of hypothesis

a la 2001, because then you can integrate over time and you can just be ready for whenever the local life forms are ready to talk to you. Yeah, that's a little. an excellent point, but I don't think that we are sufficiently interesting for them to pay attention to us. That's one thing I wanted to mention, because probably our form of life is quite common. The conditions that we have on Earth are reproduced in so many other places that there is no reason for me to expect us to be, you know, the sharpest cookie in the jar. Not only that we are common, but we are not really necessarily particularly intelligent or interesting. You know, when you look at recipe books, you can make many different cakes out of the same

ingredients. And so the ingredients on earth, the chemical soup that was on earth early on, made life as we know it and us. But I'm sure we are not the most tasty cake that one can imagine out of the same ingredients. You can have much more sophisticated cakes, much more advanced civilizations, also that existed for longer than us and therefore have more advanced technologies. And why would they be interested in us in any way? But the other thing I wanted to reinforce is your point of view that if you look at us, the way we behave, we are not doing the best things that would guarantee our survival in the long term. We are, by developing our technologies, we develop the means for our own destruction.

And the same could happen for another civilization. And it's possible that technological civilizations are short-lived because of the fact that they change the climate on their planet or they go into wars with each other or all kinds of other reasons. And if that is the case, most of the time you will find dead civilizations if you were to look at the sky. And you might think, oh, well, then I cannot establish any. evidence for their existence, that's not true because on Earth, there used to be cultures that disappeared and we find them through archaeology. We dig into the ground and we find relics that they left behind. And the same thing we can do in space. We can do space archaeology and find, for example, burnt up surfaces of planets, industrial pollution of atmospheres of planets

where the industries that polluted the atmosphere are not around anymore, but the molecules that they produced are still around. We can find the photovoltaic cells coating planets. For example, if they have a permanent dayside, they might want to use the light on that permanent dayside to illuminate the dark side.

And the civilization may be dead by now, but we can find evidence for photovoltaic cells from the reflectivity of the surface, from the reflectivity as a function of wavelength, there would be an edge. Photovoltaic cells have a spectral edge in their reflectance. And so, you know, there are various ways by which we can find evidence,

megastructures that are left behind. And I think we should search. The key is not to believe that you know the answer in advance. Sure. That's the lesson from Galileo. Yeah, but I mean, of course, I do want to talk about this.

later, and I'm torn between the idea that, yes, we should absolutely search. And, you know, it would be one of the most groundbreaking world-changing discoveries of all time, where we're to discover an extraterrestrial civilization. And at the same time, we have to be able to distinguish between, you know, hypotheses that have a 1% chance of being right and hypotheses that have a 10 to the minus 10 chance of being right. Those are very different things that we should act about them differently, right? You would agree? Yeah. But we do have one data point here, and that is that we exist and that we have life on Earth, okay? And then the second data point is that Earth is not rare.

In fact, you find a lot of planets, the size of the Earth, at the right distance from their host star, to have liquid water on the surface, and potentially the chemistry of life, as we know it. So these two facts combined, to me, indicate that we're probably not alone, that at least, you know, as a matter of the scientific inquiry of... what exists out there. You know, right now, if you look at astronomy, it's all focused on physical objects, right?

We're talking about the cosmic microwave background. We are talking about planets. We are talking about stars. All physical objects. We don't think about biological entities out there. And in fact, they may be very prevalent. It's just that the signals associated with them are weak. It's not easy to find primitive life.

You know, you could search for oxygen and methane in the atmospheres of planet. It's not easy. The signals of a spaceship, you know, are very faint. I did the calculation. No telescope on Earth can detect even a giant spaceship at the edge of the solar system, you know. The city of, just to give you an example, the city of Tokyo, if you put it on Pluto, then that will be at the limit of the Hubble Space Space Teles. telescope, if it integrates for a few weeks, it would be able to see it. So, you know, it's really

challenging to see evidence for life at great distances. And given that and given the fact that we exist here and the conditions are replicated in so many other places, I would say that it's very likely that we are not alone. It's just that it's challenging to find evidence for that. Yeah, I mean, I have to push back against this a little bit just because there's a little little bit of a leap from there are many, many planets out there, many of them undoubtedly habitable in some broad classification by how we would think about it. But then you're multiplying that big number, a la the Drake equation, by the fraction of planets on which, number one, life comes to exist. Number two, it becomes complicated and multicellular. And number

three, it becomes technological. Number four, it still survives, if it's still surviving now. You know, personally, I'm very happy to accept the idea that maybe the galaxy is full of life, but I'm also perfectly happy to imagine that life doesn't very often come into existence, or when it does, it just remains unicellular. Well, I call it the principle of cosmic modesty. I just believe in modesty, being humble and not believing that one is special, because most of the time when you feel that you're special, you're proven wrong. Okay. And so my tendency is to have, based on my experience in life, to adapt the modesty also with respect to the cosmos and not assume arrogantly that we are special or unique. That's a matter of preference. You know, a lot of people prefer to believe that they're special and unique. And, you know, I know of many people that believe so much in that notion that they never find a date. You know, when they're

They go on dates. They never find a mate, someone that they can live with because they feel that they are so special. And, you know, if we adapt this notion and we don't even search, we don't go on a date, you know, we don't even check if there is anyone out there. You know, we will live in ignorance. And that's what I hate to see, that not collecting data because of a wrong prejudice is really a terrible sin for a scientist. I think scientists should look for all the possible evidence without prejudice. Sure, no, I'm 100% in favor of collecting the evidence. But I do think that we need to imagine establishing some credence so we can figure out how much effort we should put into collecting this evidence.

And I have to confess, I'm extremely suspicious of the We Are Not Special argument, because if you say, well, I'm going to be modest and assume that I'm just, a typical, non-special person in the universe, that's not really very modest at all. You can flip that around by saying, I assume that the universe is like it is here, which is actually not very humble. It's pretty presumptuous. So I like to just not quite draw the conclusion. I like to say, well, you know, let's be open-minded about this. I should say this is not a proposal for a thesis. This is just a working, uh, assumption that allows me to go out without prejudice into the world and examine the evidence. So what I'm just asking is not to block the pursuit of evidence.

So for example, just to give you an example, right now, the mainstream of astronomy, because we detected so many exoplanets, the mainstream is advocating the construction of major telescopes, major observatories that will cost hundreds of millions or even billions of dollars to search for oxygen and methane in the atmospheres of planets. And at best, that would indicate primitive life, microbial life. There is zero dollars allocated in those plans for the search for intelligent life. Now, when phosphine was reported in the cloud deck of Venus, scientists, mainstream, scientists argued, well, you know, phosphine indeed is a result of life on Earth, but on Venus,

maybe it's volcanic, maybe it's something else. We don't believe it's necessarily implying life. So I ask the same mainstream astronomers, how dare you advocate that detecting oxygen would be indicative of life when you dismiss phosphine as an indicator of life? Now, if oxygen can be produced by breaking water and by other natural processes, why would that say anything about microbial life? Now, what you ask yourself, so what kind of molecules would convince everyone that there is life? I would say CFCs, those industrial pollutants

that we produced in coolants and industries that cannot be produced by nature. These are molecules that are extremely complex. So if we search for signatures of molecules in the atmospheres of planets, why don't we search for CFCs as much as we search for oxygen? I would say that could be a good argument for building these observatories because everyone would agree if we detect CFCs on another planet, everyone would agree that it's very difficult to make such molecules by natural processes.

Yeah, I mean, I think that, and again, all of the arguments that you have that say that we should go out there and look, I'm entirely on board with. And it's interesting, I mean, maybe let's just delve into the psychology of this, because I do also agree with you that if you say, well, let's go look for this or that molecule, maybe as an indication of primitive life, astronomers and scientists get very excited. And as soon as you say, well, let's look for evidence for technological civilizations, they get nervous, right? I mean, what is the psychology behind that? Is it that they worry that they won't be taken seriously if they act to science fictioning? Well, right now, it's social pressure and bullying and, you know, and herd mentality. But if you ask yourself, why did it get to this point? There is a long tradition of science fiction and reports without scientific credence for unidentified flying objects,

UFOs. These reports are not reproducible. They are not standing up to the scrutiny of scientific evidence. They were taken, they were fuzzy 50 years ago with the cameras that existed back then. Now we have much better cameras and they are also fuzzy. That tells you that something is wrong with these reports because we develop much better instrumentation to detect the unusual phenomena. And these are always on the borderline of believability, you know, the UFO report. So given this background and also given the fact that a lot of our colleagues get a boost to their ego if they belong to an elite club, where they do not necessarily pay attention

to what the public is interested in, but they elevate themselves to discussions on, you know, how many angels can stand on a pin, okay? or in other words, issues related with anti-de-seater space that does not represent reality or issues related with extra dimensions to which we haven't found any evidence yet, that is considered mainstream, you know, in theoretical physics. I do know, yeah. However, it's of little interest to the public. And elevating yourself to do intellectual gymnastics,

just to impress your peers, just to gain honors, awards, and to show that you are smart, that's very much of the academic game rather than, you know, echoing interest of the public. And I think it's a self-inflicted wound that academia is considered part of the elite, because, you know, it's also the scientists to blame that they are not paying attention to what the public is interested in. And we have the technology to address the question of whether other intelligent life exists out there, it's just that we choose not to use this technology in that, to answer this question. We choose not to invest funding, even at the 10% level in search for techno signatures, whereas the rest, you know, much more funds are allocated

to the search for biosignatures. And I think it's a matter of choice. It's not a matter of reason. And my goal in writing this book and also I have a textbook coming out in June 2021, 800 pages long about the search for both intelligent and primitive life with Manasvilingam, my former postdoc. My goal is to bring it to the mainstream. Yeah, now I'm completely on board in the message. And it's weird and it's hard to analyze. the biases of the academic community in an objective way, because, you know, who has the perspective of being completely unbiased? But I do think that there is a certain stuffiness, a certain insularity

that marks certain pursuits as not academically respectable and others as perfectly okay. And so that's one of the reasons why I wanted to invite you on the podcast. I'm a little skeptical of Muamua, but I'm very much enthusiastic about pursuing this as a serious intellectual endeavor. Let me give you another example that I actually was involved in, and that is cosmic inflation. So I was in a debate with Alan Gooth, in which Alan basically said that it's a silly question to ask whether inflation is falsifiable, that in fact it's a framework that cannot be falsified, that whatever data we collect about cosmology, about the universe, can be accommodated in some version of or some model of inflation,

cosmic inflation. Now, that is allowed. That is part of the mainstream, and Alan Goof represents cosmic inflation that is very widely accepted. However, people would say the possibility that a signal that we detected is artificial should not be considered because an artificial origin could explain almost everything, like pulsars, other unusual phenomena. So I would say there is a lack of intellectual honesty in, for example, treating something

like inflation or extra dimensions, or even some proposals for the dark matter. you know, we invested hundreds of millions of dollars searching for the dark matter, and many of these searches failed. We believe that it's not all the weekly interacting massive particles. That parameter space is ruled out, but nobody complains, of course, you know, it was worth checking if that idea bears any fruit. So the dark matter is not the traditional weekly interacting massive particles. That's good to know.

But at the same time, people say, why should we spend? money on searching for other civilizations if we know that we might not find anything. Well, we do the same thing in many other aspects of science. We search for things and we are not guaranteed to find an answer. I think there's still some parameters based left for weekly interacting massive particles. But let's not get into that. That's a different podcast. But I also want to just emphasize one point that you made and it went by pretty quickly, which is that when you, You are thinking about looking for evidence for extraterrestrial civilizations, advanced life forms elsewhere. You are not thinking about, you know, the CIA releasing some fuzzy videos.

We're recording this. We should tell people a couple of days after a retired Israeli general says, oh, yeah, we're totally talking to the Galactic Federation. The Israeli and U.S. governments have just hushed it up. You are not talking about that. Not at all. I think this is complete nonsense. I think our governments are not sufficiently competent to hide such an important revelation. And obviously, if we had conclusive evidence for anything, we, you know, everyone would know about it.

Yeah, yeah. Okay. And then the final thing before we get on to the details of your book, this has two many things to talk about here. You mentioned the fact that, you know, some of these civilizations could be archaeological finds. They could have gone away and we could find their remnants. But let's just get the time scales into people's brains here. If they don't go away, then we would expect that a typical galactic technological civilization would be millions, if not billions of years more advanced than us, right? That's right. And that is quite interesting because if you look at our technologies, they are evolving exponentially right now on a few-year time scale. So just imagine, I mean, we cannot really imagine what our technologies would look like 100 years from now, but giving them a thousand years, a million years or a billion years. Basically, it would look like magic to us. We would see things that look like miracles that we cannot really understand.

Well, it creates a dilemma for those of us who would want to do science on this, which is it's hard to know even what we would be looking for, right? Exactly. So what often you do, if you never met people and you're about to meet the first people, then you look at the mirror and say, well, maybe they look just like me. And then it works actually. They look similar to you as long as you have a common genetic heritage, you know, that you were connected. But when you deal with life that formed on completely disconnected planets, that is not guaranteed at all. You know, the grass on Proxima Centauri B might not be green because that star is producing infrared light. It's not producing visible light. So just think, and obviously if there are animals on the permanent day side, they have infrared eyes that look very different than our eyes. And so just imagining the same of, you know, the same, more of the same is the wrong.

And I think the wrong approach. And I think we will be shocked, both if we were to meet life from another planetary system, or if we were to meet the technologies that emerged on more mature civilizations than ours. And so we are out to a shock. And of course, that could be one reason why we haven't seen it yet because we're not looking at the right places. Even for someone who writes all the time, certain writing projects are a little bit more challenging than others.

Maybe you're writing an email to your landlord, a note to your boss, or a long message to a friend. Grammarly Premium might be the solution. Grammarly Premium gives you real-time feedback and insights to help you elevate your writing. through tone, word choice, clarity, and more. If you do write a lot, you can find yourself falling into traps, falling into repetitive things you do over and over again.

Grammarly Premium helps you tighten up your prose, make things more clear, make you come through more concisely and crisply by cutting out unnecessary words and redundant words, vary up your vocabulary by avoiding overused words. So elevate your writing with 20% off Grammarly Premium by signing up at Grammarly.com. That's 20% off grammarly premium at g-r-a-m-m-a-r-l-y-com slash mindscape. Yeah, I mean, one of the possibilities for why we haven't seen extraterrestrial life yet, even if it is ubiquitous in the universe, is the idea that we can upload ourselves, our consciousnesses, our brain states, into computers at some point.

And right now, we embodied biological organisms are driven by, all of these impetus and instincts that are given to us by evolution, to survive, to eat, to reproduce, to learn. But maybe when we upload ourselves, sort of that biology goes away and those motivations go away, and people just sort of lose interest in exploring the rest of the universe. What do you think about that one? Yeah, that's quite possible. And I think very advanced civilizations might develop social distancing on a cosmic scale. They might create their own cocoons

and basically close themselves off and not interact with anyone because they have a very comfortable habitat that they created and they don't need anyone. Now, that doesn't mean that we cannot detect them. They always need to produce trash because of the second law of thermodynamics.

So just like investigative journalists that are going to the trash cans of Hollywood celebrities, we might be able to learn something about them by looking at their trash. But it's quite possible that they have no interest in establishing contact. Now, I should mention to you an anecdote. You know, one of the biggest puzzles in cosmology is what happened before the Big Bang. Okay, what started the universe?

And I have one possible solution for that. that, you know, suppose we develop theory of quantum gravity, which we don't have right now, and we understand how the universe started, okay? And we realize that we can actually produce a baby universe in the laboratory. Suppose we realize that. Then there is a solution to what happened before the Big Bang. And the solution is that a universe like ours produces a civilization like ours,

that gets to be intelligent enough to figure out how to make a baby universe. And then a new universe comes out of us, and that will allow another civilization inside of it to create another universe and so forth. And if we were to ask, where did we come from? It will be from a laboratory of a previous species that created our universe. I like that idea. It's very similar to a paper that I actually published. But we had a natural way of making baby universes.

They were not artificially created in the lab. But the spirit of it is very much the same. And to be fair, we should give credit to Alan Gooth, who was one of the first people to show us how to build a baby universe in the laboratory. Definitely. He did a very important work. It's just that I do not agree with some of the premises in his late life. Sure.

Okay. So finally, 2017, we got a visitor from outer space. Why don't you tell us a little bit about that? Yes, on October 19th, 2017, the Pantstar's Observatory on Mount Haleakala in Maui, Hawaii, discovered the first object near the earth that came from outside the solar system. And we could tell because it moved too fast to be bound to the sun. And they gave it the name Omuomua, which means scout in Hawaiian. Interestingly, by coincidence, I visited Mount Halea Kala just a few months earlier. And at that time, Omuamua was approaching the earth rather than moving away from the earth.

It was discovered once it started running away from us at a very high speed that no rocket that we have built in the past could have caught up with it. But if we would have known about it when I visited in July 2017, then we could have designed a space mission that would meet it halfway and take a photograph. But anyway, the immediate reaction of the astronomy community was, oh, great, we have an interstellar object. It's probably either a comet or an asteroid. And most likely a comet because comets are icy rocks, that many of which can originate from the outermost part of the solar system, the orcloud.

And so if other stars have an art cloud, these are objects that are loosely bound and can easily be torn apart from their host star. And so most of the time you will get an icy rock coming from interstellar space that would look like a comet with a cometary tail. Right. Unfortunately, Omoomua did not show a cometary tale.

it looked as if it's just maybe just a rock. So people said, well, okay, so then it's an asteroid. But then when they monitor the light from it, the light changed the brightness of the object, which is just reflected sunlight, changed by a factor of 10 as it tumbled. And that means that the area of the object on the sky that reflects sunlight changes by a factor of 10 as it spins around.

and that is very extreme. We have not seen something like that before in the solar system, and it means that the object has an extreme geometry. And if you try to fit the light curve, it turns out that at the 90% confidence, you can show that it should be flattened, not elongated, not cigar-shaped, but rather pancake-shaped.

So that's another peculiar fact about this object that became clear. And the more we learn about it, the more peculiar it became. And then in May 2018, there was a paper published saying that this object exhibited an excess push away from the sun beyond the gravity of the sun. And such a push can be obtained, for example, from the rocket effect on a comet. when the ice on the surface of the comet evaporates, it pushes the comet in the opposite direction. But there was no cometary tail, and the Spitz of Space Telescope looked very carefully

at the environment of this object and didn't detect any carbon-based molecules or dust or anything that makes cometary tails, usually. And so that was a puzzle. What is pushing this object? So I wrote a scientific American essay in which I said maybe it's an artificial object. And then I wrote another more extensive paper mentioning all the peculiarities. There were six of them of this object.

It also originated in a very special frame of reference, which is I call it the galactic parking lot, where if you place your car there, nobody would know where the car came from. So this is called the local standard of rest. So it's the frame of reference that is obtained from averaging the motion of all the stars in the vicinity of the sun. And it was at rest in that frame, just like a buoy on the surface of an ocean. And the sun or the solar system collided with it because of its motion relative to that frame. Only one in 500 stars is so much at rest in that frame as Umuamua was. It was not moving at all in our local frame.

And then we bumped into it like a ship bumping into a buoy. And so there were a number of these very strange facts about Umuamua. And over the summer of 2018, I realized, well, you know, maybe it's artificial. Maybe. And then at the same time, I had a new postdoc join my group, Shmuel Biali, and I suggested to him that perhaps this person, push that the object exhibited is as a result of sunlight bouncing off the surface of this object. And in order for that to be effective, you need the object to have a large surface area

for its weight. And we figured out that a solar sail, a light sail, would do it if it has a thickness of less than a millimeter. And so we published, we submitted a paper to the astrophysical journal letters. it was accepted within a few days. They were three actually said, you know that actually there is supporting evidence that this object appears to be most likely flat

rather than elongated, and that supports your idea. And so, and that's it. We didn't have a press release or anything, but then a couple of bloggers wrote about it and the subject became viral. To my surprise, I should say, because, you know, just a year before that, I wrote a paper suggesting that the dark matter may be, may have an electric charge, a very small electric charge.

And to me, that's a bigger speculation. And nobody, you know, paid too much attention to that, even though it was published in a prestigious journal. So then, of course, there was a lot of response from both the public and the scientific community to this idea. But what I would like to mention is an anecdote that just this year in September 2020, there was another object discovered that was not identified. There was no cometary tale. But this object seemed to move in an orbit similar to that of the Earth. And it was given the name 2020S.

discovered in September 2020. And then the astronomers integrated the orbit of this object back in time and found that it must have coincided with the Earth in 1966. And it turns out that in 1966 there was a failed mission called the Surveyor 2 Moonlander and the booster of that rocket. was kicked into space. And most likely, that is what we've seen as 2020 SO. And clearly an artificially made object,

and it was hollow. And they found that there is evidence from its orbit, actually, for a deviation as a result of the push by sunlight. Right. And they wrote about it. And it's in today's New York Times science section. It says there is evidence. that the sun pushes this object

and that's evidence that it is hollow. And, you know, that's interesting because we are able to recognize artificial object like 2020 SO based on their orbit and the fact that they don't show a cometary tale. And to me, it's reminded of Umuamua, except Umuuu was not produced by us.

So, um, and the other thing I wanted to mention is, you know, when, when I go on vacation, I often like to be close to a beach and I look at the seashells on the surface of the beach and the seashells are naturally produced and each of for them looks different from the others but every now and then I encounter a plastic bottle that is artificially made

and it's clear that there was a civilization that produced this plastic bottle So perhaps Omuomua is a message in a bottle from another civilization if it is a light sail. And that's a hypothesis that we can falsify by looking for additional objects similar to it in the future. Yeah, no, I think it's definitely one worth taking seriously. So let's just because a lot of the listeners are not going to be experts in the techniques of modern astrophysics. Let's talk first about how astronomers tackle something like this. I mean, we have telescopes and we pointed at it, but we don't have an image of what the thing looked like.

We tried. We tried to look for that commentary tail, but it's just too small and faint. Is that right? That's right. It's point like the only way to get an image is to get close enough to it. And that is possible if the object, for example, is approaching us because you don't need to move very fast. you just meet it. And so hopefully next time around,

if we see an object as weird as umu-a, we will see it when it's approaching us. And it came, you were sort of remarkably close to the sun. It was inside the orbit of Mercury. And maybe that's a selection effect that if it had not passed within the orbit of Mars, then it just never would have even been noticed.

Yeah, it was noticed on its way out, but it definitely had to come very close to the Earth, within the Earth's sun separation for us to notice it. with PAN stars. And before PAN stars, we just didn't have the instruments that would allow us to detect such objects. And, you know, so it's clear. Now, the other thing I wanted to mention is a decade ago, we wrote a paper with Amaya Morrow Martin and Ed Turner forecasting how many interstellar objects we should expect and whether

pan stars should see any of them. And we concluded, no, if we just make a forecast based on what we know about the solar system and the rocks that exist in the solar system that could have been ejected over the lifetime of the solar system, we predicted an abundance of objects that is short by a factor of a hundred to a hundred million than the population needed to explain omuamua.

So the mere detection of this object is by itself a surprise. Right. And you did say about the inferred shape of it. So talk me more because this is, I was an undergraduate astronomy major and even a graduate student, though I don't do astronomy in any real sense. But I've always been enormously impressed by the ability of astronomers to take these little fragments of data like a light curve

and spin a rather elaborate tale about what we can learn. So where do you get information about, is it elongated or pancake shaped or anything like that? Yeah, so this is based on the amount of light that is reflected as a function of time. So the object, so let's imagine that we can resolve it. So basically there is a certain surface area that it occupies on the sky. It occupies a certain area. And the sun reflects of the object. We can think, for example, on satellites.

Okay, so suppose we look at communication satellites, you know, when they pass over the sky, and by the way, that's a problem for astronomy in the future. There will be tens of thousands of them that are. are planned for launch by SpaceX and other companies, and that would pose a problem for the Vera Rubin Observatory. But the point is, whenever sunlight reflects off them, we can detect the amount of light that we receive. And even if we don't resolve the object,

we see how much light we get from this point of light. And the amount of light that we get changes in time because either the object changes its surroundings, orientation relative to us, or because it spins, you know, it tumbles. So most of the rocks do not maintain the same face in our direction because they spin. And Oumu was spinning with a period of eight hours. So every eight hours, its brightness went from up, down, and then up again. So that was a full period of them.

And we can monitor how much light we get when, you know, it reflects the most amount of light versus when it's dimmer because it shows a smaller surface to us. And so if you imagine a pancake-like object, the change in the amount of light that you get as the object is spinning would be different than if you were to have a cigar-shaped object spinning. And so you can try and model it. Now, the one thing that you don't know is the reflectivity of the surface, you know, potentially there are spots on the surface that are more reflected, reflective than other parts. And that's something we don't know. But if you assume, let's say, a uniform reflectance, then it's very easy to try and constrain the geometry of the object from the light curve because we know what the sun is located. We know where the object is located in its orbit around the sun, and we can try and model that. It's not too complicated.

I think even a high schooler can do it. And is the consensus that it is more likely pancake-shaped than cigar-shaped? Yeah, there was a paper that did the analysis in great detail just a year ago by Mashchenko, Sergey Mastchenko, and demonstrated that and argued that at the 90% confidence level, it's a pancake shape. Before that, there was also the argument that if you wanted to fit the light curve, it turns out that the object with

the most amount of random internal motions, so if you imagine umu-huma being kicked around by all kinds of objects, obstacles along the path of its trajectory, then you would expect it to occupy

the highest energy state that it can get. And the highest energy state for it would be associated with a pancake. A cigar shape would be associated with the least, the lowest energy state, and that's less likely. So that argument was already made early on with the detection of Umuamua. But what was done later with all the data that was collected was to try and model the light curve. And that by Maschenko argued that at the 90% confidence is its pancake shape. Do we have any idea of what it's massive? So the mass depends on the geometry. So if you imagine it being even razor thin, like a light sail we were talking about,

it's very unlikely that it would be edge on when we look at it, right? So a change by a factor of 10 can apply also to a very thin object. We just don't know how thick it is. And the amount of mass that it carries depends on how thick it is. All we know is that one projected on the size. the sky as it spins around, the area of the object changes by a factor of 10. And the amount of mass, I should say, if you were to assume that it's a rock, you know, with characteristic density of a rock and dimensions of, let's say, 100 meters

in length and 10 meters in width, then you would get something that is something that is from the fact that it's a member of a population of objects of similar properties, you would get that you cannot easily explain its existence with what we know about planetary systems. We are off by orders of magnitude. It's just difficult to produce. You need a quadrillion such objects produced per star, and the amount of mass that each of them carries makes it quite difficult to explain. And Amaya Moro Martin wrote a couple of papers on that, how difficult it is to produce if it's a rock.

So many of them so that we will see one within a few years with pan stars. However, if you make it like a light sail, it doesn't carry as much weight, actually. It could be a quadrillion such objects would carry the mass of an asteroid that has a size of roughly a kilo. or so. So in principle, there will not be a lot of mass associated with umu-umua if it's very thin. All right, quick quiz for the hiring managers out there. What's worse? Being understaffed or being poorly staffed? Well, that's a trick question, because both are recipes for chaos. Either way, just say to yourself, this is a job for indeed sponsored jobs. You'll get matched with candidates that meet the skills, certifications, and everything else you're looking for.

Or go a different way and get no traction. Seriously, sponsored jobs posted directly on Indeed are 95% more likely to report a hire than non-sponsored jobs. It really is a no-brainer. Spend less time searching and more time actually interviewing candidates who check all your boxes. Less stress, less time, more results. When you need the right person to cut through the chaos,

this is a job for Indeed sponsored jobs. And listeners of this show will get a 75% dollar sponsored job credit to help your job get the premium status it deserves at indeed.com slash podcast. Just go to indeed.com slash podcast right now. Indeed.com slash podcast. Terms and conditions apply. Need to hire?

This is a job for Indeed sponsored jobs. Love bread, bake goods and pasta, but not the way they make you feel? What if I told you there are macro-friendly options that don't taste like sawdust and sadness? Satisfying sandwiches, fully loaded bagels, noodles that can stand up to your favorite chunky sauces, All delicious. Craveworthy and smart, each serving of Hero Bread has up to 19 grams of protein and 32 grams of fiber and just zero to five grams net carbs and zero grams sugar. Hero Bread bakes with heart-healthy olive oil and delivers this soft, fluffy, flavorful experience you love. Breakfast burritos, smeared-loaded bagels, real mac and cheese.

Hero Bread bakes loaves, bagels, and tortillas that don't taste or feel like cardboard. Noodles that don't fall apart in hearty sauces. Plus, limited edition small batch bakes like the 2 grams net carb. hero croissant or one gram net carb hero cheddar biscuit handmade in a sonoma based french bakery shop now on hero.co use code iHeart for 10% off that's hero dot co. That's hero.co. For serving metalo calorie foods and products contain aliasi nutrition info on hero.com for sodium and sugar content. Yeah so in the interest of still normalizing the expectations for what kinds of things might be out there for our audience you know astronomers have thought about this a lot but maybe the people in the

street haven't. You've mentioned rocks and you've mentioned comets. And so those are a little bit different, right? Rocks are solid and comets are made of ice or other volatile things that can light up when they come near the sun. And maybe there's some sort of in-between thing where there's a loose agglomeration of rocky and icy things. And we think that all these things are in our solar system, right? We find them, but the Orch Cloud and maybe the Khyper Belt very far away are more icy, more rocky? What kind of stuff do we expect? The story actually, since you did your PhD at Harvard, I should mention the story starts with Fred Whipple that used to be at Harvard. And I think he got the idea, it wasn't clear at his time what these comets are. And he came after going through Harvard Yard,

during a snowstorm, he came up with the idea that, you know, they might be dirty ice. Or it turns out that they're more likely icy dirt. So in other words, it's mostly a rock. I mean, comets are mostly a rock and they have some water ice on them. Now, one thing about water ice to keep in mind is it doesn't go to liquid if you, warm it up in space. In order for water to go to liquid, as we find on earth, you need an atmosphere, you need an external pressure. And that doesn't exist on a small rock in space. And so if you warm it up, when the rock gets close to the sun, the ice sublimates directly into gas. And that's

what we see is the cometary tale. We see the gas that is created by warming up the ice. And so the solar system had basically the debris that was left over from the formation of the sun created this protoplanetary disk, a disk of material that was orbiting the sun. And the small dust particles collided to make bigger and bigger rocks. And beyond a certain distance from the sun, there was ice, water ice, because it was too cold in that disk. and water could not exist in gas form, so it solidified into ice. And that's how you get these icy rocks in the outer part of the solar system

where the conditions were cold enough for them to form. And these are relics of the formation of the solar system. You have all these rocks moving around, and some of them were kicked by planets and occupied the or cloud. And some of them were donated to our solar system from other stars as well.

So they are orbiting the sun at great distances that go out to 100,000 times the Earth's sun's separation. And whenever one of them passes close to the sun, we see it as a comet. And every now and then, we also get some objects to collide with the Earth. That's what killed the dinosaurs. Unfortunately, the dinosaurs didn't have science and astronomy,

so they couldn't have studied the sky and as a result, they saw this giant rock heading their way and they couldn't do anything about it, hopefully, you know, we, by pan stars, by monitoring the sky, can alert us to any dangerous rock that is heading our way and perhaps we can give it a nudge

so that it will not hit the earth. Here in our solar system, then, you know, we have these rocky things and these snowballs, these comets, and presumably some of them are kicked out of the solar system, right? from either random jinglings due to planets or maybe in other circumstances

there could be explosions or collisions. So therefore we would expect some flux of interstellar visitors here visiting us, right? Definitely. In fact, the or cloud extends halfway to the nearest star, the Alpha Centauri system. And those old clouds, if each star has an old cloud around it,

you can think of them as billiard balls that are touching each other. So space is full of these or clouds. And it's easy for a star to pass near an old cloud of another star and tear it apart, basically get some objects kicked out. And therefore, the interstellar space is full of object. And it should not be a surprise that some of them enter the solar system. And that's what we calculated a decade ago. But we just didn't expect an abundance so large as to explain a umu-a-a-like object because what we calculated

is the natural density or abundance of such objects is not high enough for pan stars to detect any of them. But apparently, it did. I should say there was a second object, interstellar object, detected, and that is by an amateur

Russian astronomer called Genadi Borissov. And he built a telescope and detected what looked like a regular comet that is not bound to the sun. And then people came to me and said, well, this one looks just like a regular comet, this interstellar object. Doesn't it convince you that Omoaumua was also natural? And my answer to that was, you know, when I went on a date,

the first date with my wife, she did look special to me. And the fact that I met many other people afterwards didn't change that opinion. So the fact that we saw Borisov looking like a typical comet didn't make Omuamua more typical. I guess the thing that is most provocative about Amuamua is the combination of the fact that on the one hand, it did accelerate, right? I mean, there was some non-gravitational push, which by itself is not surprising because comets do that when gases light up and push away. But on the other hand, we didn't see any such outgassing. Is that right? Is that the real tension that we're working to fix here? That's the main peculiarity that it exhibited an extra push without a cometary tale. And that led a few mainstream astronomers to come up with innovative ideas.

For example, maybe it's a hydrogen iceberg, something that we have never seen before. The problem with that, and we wrote a paper about this with Thim Huang, showing that a hydrogen iceberg would not survive the journey. It would evaporate over the millions of years that it takes it to reach us from a distant molecular cloud. And the reason that a hydrogen iceberg was proposed is because in that case, you would not see a regular cometary tale. It would be made of hydrogen that is invisible, an invisible gas. And also it would give, because of a it's so light, it would give more of a push. But I don't think, well, first of all, hydrogen icebergs were never seen.

But moreover, we have good theoretical reasons not to expect them to exist. And then another idea was maybe it's a dust bunny, you know, the kind of things you find at home when you don't clean home very often. And the idea there is that maybe it's an object that is a hundred times less dense than air. So it's very fluffy and porous. And that kind of an object can be pushed by sunlight. So it doesn't need to be a light sail.

It could be a dust bunny. Here again, I have a problem with its survival over millions of years in the interstellar medium. I just have a hard time imagining a dust bunny of the size of a football field, spinning around every eight hours, and surviving a journey of millions of years. And, you know, it's just less plausible to me.

But I should say that, you know, while people were coming with these challenging scenarios and these are people from the mainstream, other people from the mainstream were arguing, forget about it. It's natural and that's it. End of argument. There is nothing to discuss. And I find this to be a very strange situation where some people have a hard time explaining the facts that we know and others are claiming forget about the fact.

Let's move on business as usual. Yeah. So, I mean, the nice thing about the light sail hypothesis is that it would be something which would be big and flat, very, very thin, but also robust against just surviving for a long time in interstellar space. Exactly. That's one thing we checked in the paper. That was the first thing we checked. Will it survive all the dust that is bumping against it and the interstellar medium, the radiation, so forth? And we found that there shouldn't be any problem. So, I mean, this is a falsifiable, unlike inflation, it's falsifiable, a falsifiable hypothesis in the sense that, you know, we just need to find another object that shows similar properties and then, you know, take a photo. graph of it or just get more data on it. I'm just proposing this conjecture as a testable hypothesis, and there is nothing different from suggesting, this is nothing different from suggesting that the dark matter has a small electric charge that you can test in the laboratory in principle or any other scientific inquiry. And it's only the emotional blockage or the taboo that is put by

the scientific community that prevents us from going in these directions right now. My impression is that the biggest challenge to the light sale idea is the tumbling. You wouldn't quite expect a light sale to tumble in the exact way that this one does. But am I right about that or did I make it up? Yes, you're right if it's functional. If it's something that was designed to maintain its integrity in a way that, you know, it's operational right now. But if it's, you know, just a piece of equipment that is defunct by now,

or serve some other purpose. I'm not sure. This is guesswork. The question is what really physically speaking, what is this, what is this object? What's the geometry? What is it made of? Is it shiny, just a shiny rock?

Or is it shiny because it's made of metal? You know, that's a simple question. It turns out that the Spitzer Space Telescope did not detect any heat coming from it And given the amount of sunlight that it reflected, it looks like it was more shiny than average, an average asteroid or comet. So it's just a very simple question. What is it made of? How does it look?

And we can answer this question with existing technology. We just need to monitor the sky for more of the same. So, I mean, let's, you know, we've been talking and been serious scientists for a while now. We can let ourselves speculate a little bit more. if it is artificially constructed by an alien civilization, why would they do it? What is your idea about what purpose this thing could have served to its initial constructors? Yeah. So again, I go back to the evidence.

And this object was in the local standard of rest and sort of the galactic parking lot, a place where you can't really trace where it came from. And why would it be in that frame? And one possibility is that there is an array of these things, and they are used for navigation or for relay stations, for communication. There could be many possibilities. Why would you construct a set of systems that are at rest in the galactic frame? So that's one possible use, that if you were to navigate through the low,

volume of the galaxy, you want to have signposts, or if you wanted to communicate, perhaps relay stations, if you send out spacecrafts. I don't know. I mean, it's not clear to me, and it could just be some debris, you know, left over from equipment that is dysfunctional by now. But the point of the matter is that we can tell, we can tell something artificial, can tell the difference from a piece, from a rock. And clearly, you know, if a caveman were to find a cell phone, the caveman, based on experience, would say it must be a shiny rock,

because that caveman saw rocks all of his life. You know, that's the thing that he's familiar with. But obviously, with more sophistication, the caveman will conclude, oh, this is an unusual object and not something that I have seen before. And so we can do the same. We can attempt to do the same

by getting more data, rather than claiming one thing or another based on prejudice. Presumably, we did listen to see whether there were any radio signals or other things being given off that would be manifestly artificial coming from a mua, but we didn't find any? Yeah, in fact, a couple of weeks after it was detected, I visited Uri Milner's home in Palo Alto and discussed with him the possible use of the telescopes. that the breakthrough listen has access to, to monitor if there is any radio signals coming from Oumuua,

that was done and nothing was detected. But it doesn't tell us much because perhaps we are not listening at the right frequencies. Sure. You know, even if it's transmitting, it could be transmitting at times that are special, not when it was passing near us. So although interesting that, you know,

that possibility, there was no signal detected, that possibility is ruled out that it was transmitting at the frequencies that we were listening to. I mean, it's of limited use for ruling out an artificial origin. Well, so you mentioned, let's again be a little bit more speculative now late in the podcast. This is how we get. So you mentioned the, was it, the breakthrough Star Shot program? You're heavily involved, Mumu Aside, in our attempts to contact or communicate or visit potential alien civilizations elsewhere. Yes, so I chair the advisory board for Breakthrough Starshot, which is an initiative attempting to develop the technology that would allow us to visit other stars.

And the idea there is that by physically visiting the neighborhood of a planet, we can learn much more about whether life may exist there. And the only problem is that the nearest star, Proxima Centauri, is four and a quarter light years away. So it takes light four and a quarter years to reach us from that star. And in fact, if there is, in fact, next to Proxima Centauri, there is a planet, Proxima B, in the habitable zone. And if there are people out there, they still do not know the results of the election of 2000. 2016 because those signals will get there only in February 2021. And it just shows you how long it takes for signals to get from one star to another. But that means that if you want to reach the nearest star within our lifetime,

meaning within 20 years or so, which is the goal that Yuri Milner posed when he came to my office and asked whether I would like to lead this project, if you want to do that, you need to send a spacecraft that moves at the fifth of the speed of light. And that is very challenging. And that's the technology that breakthrough starshot is focusing on. And I told him, when he asked me, I told him, well, I have to think about it with my students and postdocs. We thought about it for six months. And then we came up with the suggestion that the only technology that works is pushing a light sail with a very powerful beam.

and having a payload that is very lightweight, only a gram of material that has a camera, communication device, navigation device. That's possible with present-day miniaturization of electronics. And with a light-cell technology, if you have a laser of 100 gigawatt shining on a sail that has roughly the size of a person outside the atmosphere. You can launch the sail to a fifth of the speed of light over a few minutes,

by which time it will be five times farther than the moon is from us. And then if you launch it in the right direction, it can carry the electronics to the destination and take a photograph of the planet. So that would be a way of, getting there quickly enough. And otherwise, if we were to send, for example, New Horizons or Voyager 1 and 2 like missions,

it would take them 50,000 years to reach Proxima Centauri. And, you know, that's the time that elapsed since the first humans left Africa. So if you wanted to get there today, we would have needed to launch the spacecraft when the first humans left Africa. But these breakthrough star shot, one gram little fellows, would be, they wouldn't be landing anywhere.

They'd be passing through these other solar systems at point five. And by the way, and by the way, I should mention that, you know, if there are one gram spacecrafts flying through the solar system, we would never notice them.

Well, I was going to say that the idea of this, you know, you would push it and it's, it's, you're pushing the one gram by itself, or is there a little sail attached to it? There is a sail attached to it, and the sail weighs roughly a gram as well. Yeah, okay.

But since it's so thin, it's less than a micron in thickness, maybe a tenth of a micron, and roughly the length, the height of a person, you know, that is sufficient, you know, to bring the payload to a fraction of the speed of flight. payload is attached to it. There is the question of what geometry to give to the sale.

You know, it's not clear that the flat geometry is optimal because it may not ride in a stable fashion on the laser beam. So we consider, for example, a sphere or other geometries. But it's still work in progress. We are currently addressing three challenges in this project. One is developing what we call the photon engine, which is the laser that produces the very powerful beam on earth. And the second challenge is the light sail,

making it of a sufficiently strong material that is highly reflective and doesn't absorb much of the laser light because otherwise it will burn up quickly. And the third challenge is communication at those great distances. That's not easy. If you want to transmit a photograph from the, distance of Proxima Centauri B to the earth. It's a major challenge, actually. Yeah, no, no, I can imagine that. And just to be super duper clear, the idea that you're sketching kind of bears a family

resemblance to your idea for Amuamua with the very large difference that a Muamua is not moving anywhere near that fast. That's right. You know, the reason I thought about the light sale in the first place is because I was engaged in this project. Now, you know, you know, If you look at the history of the search for extraterrestrial signals, when we developed radio technology for communication purposes, then we started to search for radio signals from the sky. When we developed lasers, we started to look for that. And I mean, obviously our imagination is limited by the technologies that we have.

And we cannot imagine things that we have not mastered ourselves. So I find it completely natural to consider what we know. So since we are developing light sails and, you know, breakthrough starshot is not the first to embark on this challenge. And the planetary society launched Lightsail 2. And at Jaxsa, the Japanese Space Agency, had a demonstration of a light sale. So, you know, this is maybe the wave of the future in terms of space exploration.

And if we are working on that, Why not imagine that another civilization already mastered this technology and it's very common? Well, given that we are just beginning to even contemplate these technologies and think about them, whereas other civilizations we might bump into have been around for, who knows, hundreds of millions of years longer, is there some credence to the idea that we should be prudent and not draw attention to ourselves? Should we be worried about letting people know that we're here? I think it's prudent to actually look.

and not make too much noise. But unfortunately, you know, the cat is out of the box. We already transmitted. We were careless over the past century. The most loud, the loudest signals that we produced were with anti-ballistic missile radars. So after the Second World War, there were these radars, very powerful radio transmitters. that were searching for ballistic missiles from the ground,

and their beams were extremely powerful. They can be seen by our radio telescopes across distances of tens of light years. So we already left some imprint, and we should hope that nobody hostile is on the other end, receiving it, because eventually we will find out, if there is such entity, I think it's prudent not to make too much noise

to just search for evidence for what is out there. Because based on human history, there were lots of predators, cultures that were more advanced and were trying to conquer new lands to harvest the resources there and dominate those lands. And so there is no reason for us to,

be too loud. I think we should be quiet and first listen. That certainly makes sense to me. I know some people are very eager and convinced themselves that if a technology, if a civilization becomes especially technologically advanced, it must also be benevolent. But it's a big risk to take, right, when we don't really know for sure. Yeah, it's a big risk. And by the way, speaking about risk, I do think right now all of our eggs are in one basket, the earth. And it would make a lot of sense to spread the eggs in different baskets so that if something catastrophic happened on Earth because we misbehave or because of some catastrophe,

at least humanity will exist somewhere else. And it's sort of like the Gutenberg revolution with the printing press. And before that, there were very few copies of the Bible, and each of them was handwritten and very precious. But as soon as you made the duplicates with a printing press, each copy was not as valuable. If something bad happened to it, you could always find other copies. And I think we, as a civilization, if we find life, as we know it, very precious,

we should produce copies and send them to places. And so going to Mars is a good idea. Going to beyond the solar system is a good idea. We cannot rest assured that if we stay here on. earth, the things will go our way. What is your attitude toward the fact that other stars are very far away vis-à-vis our ability to get there? Do you think that it makes sense for human beings to try to extend?

I don't think we need to get there. You know, I just wrote a scientific American article called Noach's spacecraft. The idea was, you know, what is the modern version of Noach's arc? So Noah was worried about the flood, and he collected all the animals according to the mythological story of the Bible. He collected representatives of elephants and, you know, monkeys, all the animals put them on a big arc that he constructed so that they would survive the flood, so that the precious life on Earth would survive the flood, the great flood. And you can imagine doing the same thing with a spaceship. But my point is that this could be a

cube set. You don't need Noach's arc, which, by the way, the Bible mentions the dimensions of, and there were 100 meters by 10 meters and so forth, very similar to the dimensions of umu-a-moa. But getting back to the point that, you know, with a CubeSat, you can put a very capable computer on board and a 3D printer and artificial intelligence equipped the computer with the ability to store all the information, the genetic information, let's say about, the life forms that we find on earth. And then if we understand how to make life artificially, then you can imagine that the 3D printer,

you know, once it gets to a place where there are raw materials, it could make life as we know it there. So instead of transporting, like Noach's Ark, transporting people to places, you can reconstruct them there by just carrying the information about their DNA and using 3D printers to make life, as we know it, in distant locations. So that's my version, just a CubeSat. You don't need a giant Nox arc for that purpose.

Well, I have a couple questions about that. Would it be the right thing to do? Would it potentially get in the way of indigenous life growing up? That's a good question. It depends how much you value our life, to what may happen elsewhere naturally. And, you know, if you're a naturalist, like Thoros, I live very close to Walden Pond, where Thorough wrote his book.

And if you're a naturalist like Thoros, then you would argue we should avoid contaminating other places with our life. And as much as possible, because nature is precious, let them, you know, and if we perish on this planet, so be it, because that's our natural way. So you can argue that. You can say, you know, whatever happens to humanity on Earth, you know, that's our fate. And if we perish here and nobody hears about us in the distant future in the universe, who cares? The universe is large, lots of things are happening in it.

And we don't amount to too much, you know, we shouldn't assign significance to our life. But on the other hand, if you think, oh, actually we value life very much and we want to maintain its long-term future, then you want to make many copies of it. And I'm sure, you know, there will be people on both sides. I think the naturalist approach would be less popular based on the way we behave with our industries and how much care we take of our planet. If you look at it right now, I think that most people care. about reproducing themselves

rather than maintaining the environment. So many things to talk about here. Yes, I think that there's, I'm intrigued by this. I would want some sort of dead man switch, some sort of dead planet switch. Like if we destroy ourselves, then we spread ourselves elsewhere,

but otherwise we can be a little bit more circumspect. Yeah, that's, it reminds me of what at some point, a friend of mine said that he wants to have on his web, website button saying click here after I die. And then when you click there, you will find the full obituary that includes all of his scientific accomplishments. It's a similar idea that, you know, when catastrophe hits, only then you activate your plans. Let me give you a chance to say one more thing about what you've alluded to already, which is a

sort of the lessons for this kind of discussion we've been having for how science is done, both within academia, choosing topics and valuing certain kinds of research being done, but also the fact that whether we like it or not, some of our research is carried out in the public eye. And the public, on the one hand, wants to trust science. On the other hand, science is sometimes not done yet. And how do we make that balance? Yeah, so I think the most undervalued. quality that I would like to highlight is innovation.

I think it's extremely important for the scientific community to encourage to cultivate innovation. And right now, it doesn't look like that. A lot of the funding for grants is given to mainstream ideas that, you know, just add a nuance on an existing theme. And the reason is simple, because the people on the committees, the selection committees, are mainstream people that want to create echo chambers where they advocate how significant their contribution to the field was.

And the way to achieve that is by educating students to reproduce what you've done and so that you get this echo chamber of people saying the same things with more details. It's just a mechanism for boosting their ego in some sense. And if you have people like that on selection committees, they would try to fund the projects that support their activity throughout their career and continues to do along the same line rather than innovate and criticize and be open-minded about alternatives.

And I think that's bad for science. And in fact, if you look at the public sector, the commercial sector, you find that companies like Google do have within them blue sky research. And that was true of Bell Labs in the old days. And a lot of innovation came from that, a lot of Nobel prizes. And so if the commercial sector recognizes the value of innovation more than the academic community,

that's an unfortunate situation that we are at. And I think it should change. I think there should be a fixed fraction of the funds allocated to innovative thinking. It will also change the atmosphere that there would be less bullying of anything that looks different. You know, if you go to kindergarten, you see kids always bullying those that look different. And the scientific community does the same thing. You know, whenever a proposal for an idea that is different than the one that is commonly adapted is made, then people bully that proposal.

And that's, I think that's bad for the health. of the field, it's bad for science. We should be open-minded. We should criticize based on evidence and rational arguments. So that's point number one. The second is, you know, kids often are innocent when they explore the world. They don't do it for their own, for boosting their ego and so forth. I would very much like my colleagues to behave more like kids, you know, like being open-minded and discussing possibilities without.

dismissing them ahead of time. And I wrote an article about this to the Harvard Gazette, in which I encouraged my colleagues to behave more like kids. That would be my wish. Both in terms of funding and in terms of interactions with each other, I see that a lot of work needs to be done to make the scientific inquiry more honest and straightforward. No, I'm 100% in agreement with you there, and I've come across the bullying. There's a thing that grows up as a scientist matures where they try to discriminate between good work and bad work, and it's not always completely objective, and they have their biases, and it's just remarkably fast how quick scientists can knock down work that they're not familiar with.

But on the other hand, I recognize there's a lot of crack pottery out there also, and it's not worth supporting. so it's just so hard to get that balance. Exactly. This is called natural selection that, you know, I think the evidence, evidence and data should be the rulers rather than people's opinions. So, you know, what you find are fields that are saturated with subjective judgments as to what is appropriate to look at without any evidence. You have string theory for five decades being very popular, no evidence.

and it's now not even predictive as to what we might look for in order to falsify it. And then, you know, you just have these cultures that are self-pertuating without a need for evidence anymore. Evidence is not the oxygen that drives them. It's more intellectual gymnastics. And I find that dangerous because that's the way Aristotle operated, you know, the ancient Greeks. And we've learned a lot since then that evidence is extremely. important for the progress that we have and we've made progress, but there is some retreat.

And there are even people advocating that we live in a simulation, which I find, you know, just like being on drugs in a way. Well, this is exactly the problem. One person's scientific investigation is another person's, you know, waste of time. So I'm agreeing with you in principle. I don't have any concrete suggestions for making it better, but it's something that we should try to think about. But let's close up by asking a very different question.

You're very well known for working on many different kinds of things. We've been talking about search for extraterrestrial life and Amuamua and stuff like that, but you're also the founder of the Black Hole Initiative and so forth. Let me give you this opportunity to say, what is the most interesting thing you're working on right now that has nothing to do with extraterrestrial life? Well, we think that we discovered the nearest black hole. And it's about a thousand times the mass of the sun. And it's at a distance of a few hundred light years from us.

Completely unexpected. We found some evidence for it. The paper is being refereed right now. To me, that's very exciting. Because, you know, a black hole is a place. If I'm asked, what would I like to visit? I would like to visit the vicinity of a black hole, not get into it. because then you have a limited life inside

before your body gets torn apart, but looking at it from a close distance would be quite amazing. And so actually at a conference, at the annual conference of the Black Hole initiative that we have at Harvard, that I'm the founding director of, I once suggested in my closing remarks, I said, you know, a black hole represents one place

where you can actually test string theory, And the string theories should plan on a field trip. You know, if we have a nearby black hole, we should go there in the next conference so that they can test. They will test the theory by entering the black hole and getting close to the singularity. And when I suggested that, Nimarkani Hamid shouted from the audience, you must have an ulterior motive for sending string theories into a black hole, to which I didn't respond. You did not respond. I will not make you respond right now.

We'll let the audience think about that. So Avi Loeb, thanks so much for incredibly provocative and fascinating conversation. My pleasure. Thank you. In I shop Ashtro. At Astro, I find statement dresses, powerful suits and Afrocentric styles made for my life. Church, celebrations, date nights, moments that matter. From head-turning outfits to the finishing touches, wigs, hats, handbags, and shoes, Astro helps me show up confident.

For me, it isn't just fashion. It's how I express who I am. Shop your style at astro.com. That's ashro.com. What if you could have even more and more and more help to pursue your goals? At LPL Financial, we offer more ways for advisors and their clients to thrive. So what if you could? Paid advertisement. Investing involves risk including potential loss of principal,

LPL Financial LLC member FINRA SIPC.