The Search for Space Aliens

We're looking for that techno signature. What's happened on planet Earth probably isn't a miracle. There are lots of planets out there. That's the fundamental problem. We just don't have the data. Do you think intelligent space aliens exist? Hello and welcome to the fifth anniversary edition of the supermassive podcast from the Royal Astronomical Society. The science journalist Izzy Clark and astrophysicist Dr. Becky Smethurst. I think it's too late in January to say happy new year now. But anyway, bring on a supermassive 2025, I guess is what I will say. Yeah, I can't believe we've been doing this for five years. That has flown by. Where did the time go? And also, how are we only getting to the topic of extraterrestrial life right now? Yeah. I honestly can't believe we haven't done this episode too now. So this episode is all about the scientific search actually for extraterrestrial life. Yeah. Where are astrophysicists looking? How do they search for signals? And what the heck is the plan if we find extraterrestrial life? I'm sure people would like to know. All of that is coming off in the show. But before I get into it, I need to do a little bit of admin. Okay. Fun. So all of us here in the supermassive team wanted to let you know that from next month we are going to start having adverts on the podcast. We want to keep this podcast free for everyone and this is just simply to help keep the show running. However, if you really don't want to hear adverts and would be interested in paying for an ad-free version, do get in touch on emails or on Instagram. We don't actually know how to do that yet. But... But is he real figuring it out? Yeah, I'll figure it out. And it's just, if this is something that people want, we will look into it. So yes, just email us. Or message us on Instagram. We'll work it out. No, right. Admin, done. Let's get into the good stuff. Absolutely. Dr. Robert Massey, the deputy director of the Royal Astronomical Society is here too. And I have to ask you both, do you think intelligent space aliens exist? I mean, who knows, right? But I guess I do simply because the universe is so, so big. But as for how many there are, how frequently civilizations emerge and end, we really don't know. It's one of those fascinating fields where we just simply don't have. We have a lot of ideas about how life might develop, how intelligent life develops, philosophical ideas about the demise of civilizations, but no data. That's the fundamental problem. We just don't have the data confirming that life is anywhere else in the universe yet. But I guess, you know, if there's a thing we're going to try and solve in the 21st century in astronomy, surely this one, surely by the end of the century, you'd like to think that maybe we'll be in a position where we say, you know what, we probably are alone. Or guess what, we found life, maybe at least bugs elsewhere in the server system. We'll find out. Yeah. For me, like if I start off with the, like, do I think other intelligent life has existed somewhere in the universe at some time or other in the past 13.8 billion years in the universe's history? I'm like 100%. Yes. Like distant galaxy, whatever flash in the pan, like life, intelligent existed and then died out again. Fine. But then as I start to qualify that more, I guess I'm like, what about in our own galaxy? I'm like, now I start to doubt it. And then if I start thinking about, well, not just in our own galaxy, but like, what about at the same time as we exist? I think it's the bigger one because we think about how long it's took for life to develop on Earth, like billions of years. And then we think about how long humans have been around for. I don't know. I don't know. I don't know. I feel like tens of thousands, hundreds of thousands of years. And then we think how long humans have been around for intelligent enough to observe the sky and understand what we're seeing. Like that's less than 100 years. And the fact that like there could be a chance that, you know, a similar civilization to us existed out there in the universe that we could find, not only in the universe, but that we could find in our own galaxy, the Milky Way. Like it seems less and less likely to exist at the same time as us. Yeah. And I think you and I on the very much the same page on that aspect, it's like the probability of the two coexisting at the same time, trying to communicate with each other. It's slim, but we'll still try. And we start saying that when people are like, why haven't we found aliens? It's like, well, we just want the timing right, you know? A relationship. I just don't have a timing right, you know? It's not working for both of us. And Robert, there is an equation that can be used to help us on this search for potential intelligent civilization. So can you talk us through that? Yeah, sure. I don't propose to read out the whole equation, but it's famously the Drake equation. It was developed by astrophysicist Frank Drake in 1961, who was also something of an enthusiast for the idea of searching for extraterrestrial life, you know, directing radio observatories to do that and so on. And his idea was to try and estimate the number of civilizations currently in the Milky Way galaxy that could be communicating. So, you know, going back to what Becky was saying about, are they here now in our galaxy? And it's based on the sort of average star for a ratio and rate, the fraction of those stars that have planets, the number of planets that can support life per star that has planets, the fraction of planets that could support life that actually developed life, the ones that go on to develop intelligent life, the fraction of those that develop the technology to communicate, to transmit their existence into space, and then the length of time for which these civilizations exist or are actually able to transmit signals into space. And based on that, you know, in theory, you can calculate how many civilizations are out there and communicating right now. But obviously, the big problem is that we only know really the first three or so of those terms. So we know, you know, we have an idea about the average rate of star formation. We now, because of telescopes like Kepler and all the work that's been done on detecting planets around other stars, we have a better idea about the fraction of those stars that have planets. That's changed a lot in the last 35 years. And we are getting to the point, I think, slowly where we can talk about the number of planets that can support life around a star, you know, that actually has planets. But the rest of them, of course, or the rest of it that talks about whether life exists and how many of those are advanced civilizations, how many transmitting, we just don't have any data. So it's an equation where you've got the first three terms, and then the rest of it, they're blanks, they're question marks, you know, so you multiply a question mark by a number, you basically add a question mark, and that's where we are. So we do not know. The other idea around this is the Fermi Paradox. And that was physicist Henri Coferme, who is the quote attributed is sort of where is everybody or, you know, if there are aliens, why aren't they here? And it was the physicist Henri Coferme, who said this in the 1950s. And his argument was that if intelligent extraterrestrial life is common, then there should be a lot of advanced civilizations in the galaxy. And at least some of them or their space probes at least should be here. Because if they, but if you look at the age of the galaxy, you know, and the age of the universe, 13 billion years, 10 billion years over the Milky Way, then it seems reasonable most of those advanced civilizations would be older than us. And if they've been around even for a few million years, they ought to have had time to reach us. So, you know, setting is, you know, I'm not going to dismiss alien abductions and all the rest of it. Basically, there's no evidence of alien life having reached the earth. And so the argument, the conclusion that might be perhaps we are alone, which in itself is a pretty challenging idea too. So, you know, but you can see there's a lot of big unknowns in this whole discussion, which is what makes it so interesting. Yeah, I guess it's kind of like even if every intelligent civilization is sent out like an equivalent of Voyager, right? Yeah. Millions of years, it should have got somewhere by now and flowed through something. Yeah. It's kind of depressing to think about. It's just timing again, you know. It's all down to timing. Cheers Robert. We'll catch up with you later in the show for some more questions. And of course, this month's Stargazing Tips. There are various methods to search for intelligent life, but where to begin. And what classifies as intelligent life? Are we intelligent life? Am I? Not sure. I have my good days. So, I reached out to the SETI Institute in America. This is a research organization with a multidisciplinary approach aiming to search for and understand life beyond Earth. I spoke with their senior astronomer, Seth Shostak, and you'll hear us mention SETI a lot. So, that is the search for extraterrestrial intelligence. Well, SETI is actually just kind of a scientific experiment, or maybe you should say a science experiment, trying to find any cosmic company, any other inhabitants of nearby space that might be intelligent enough to build a radio transmitter so that we could pick them up. And do you think there's alien life out there? Well, obviously I do, because I work for a SETI Institute. But yeah, I think that the usual argument for why the aliens must be out there is simply the principle of mediocrity, as it's called, which is to say that what's happened on planet Earth probably isn't a miracle. There are lots of planets out there. There are roughly a million, million planets just in our galaxy. Some of them may have cooked up intelligence, and ours is probably not the only locale where there are thinking beings. And so, if that's the case, and I just feel that that's only reasonable, then it certainly doesn't hurt to try and find them. And so, for you, what classifies as intelligent life? Well, intelligent life, I mean, you know, there's just the operational definition. If they can build a radio transmitter, then they're intelligent life. Or if they could build a big laser and flash signals into space. If they can do something that makes them able to communicate across the distances between the stars, then we call them intelligent. We don't require anything else. We don't have to write good books or, you know, pass an IQ test or anything like that. We just have this operational definition, right? Okay. And so, how do you look for life? You know, where to even begin on that search? Yeah. Well, I mean, there are two kind of separate disciplines here. One is just looking for extraterrestrial life, and the other is looking for extraterrestrial intelligence, which is a little different. If you're, if you would be happy with just finding some biology on another world, then probably your best bet is to look in our own solar system, because we can send spacecraft to places like Mars or some of the moons of Jupiter that probably have hidden oceans, and there may be life there. Now, mind you, that life might not be terribly interesting to invite to your book club, because it's probably going to be things like bacteria and so forth. If you're interested in looking for intelligent life, that's a different thing, and that's something like SETI, or, I mean, there are other approaches that you could take too. How does SETI do it? Talk me through it. What's the process of looking for signals, for example? Yeah. Well, it has been traditionally a search for signals, and that goes back to about 1960, when an observatory in West Virginia, the National Radio Astronomy Observatory, constructed a new antenna. And one of the people that was working at the observatory at that time was a postdoc by the name of Frank Drake, and the director of the observatory said, Frank, we got this new antenna, think of something to do with it. And there are many things he could have suggested, studying certain categories of active stars, including the motions of the gas between the stars and so forth. But he said, look, let's try and eavesdrop on signals that might be out there being produced by transmitters on other worlds. And that was, if you will, the start of SETI. And how has that developed over the years? Yeah, I mean, people will ask, okay, you're trying to eavesdrop on the ET, but how would you know that a signal is actually from an alien as opposed to something else? I mean, there are plenty of natural radio transmitters in the universe, if you will, you know, pulsars and quater stars and other other objects, even planets of that matter. But the signature of a signal that's being produced by a transmitter as opposed to natural phenomena is that it's narrow band. It's confined on the radio dial to one small set of frequencies there. That's a transmitter. Can you talk me through that a bit more? What frequencies are you looking at and how extensive is this search? Yeah. Well, I mean, that is a good question. The idea that you might find ET by, you know, finding a radio signal that they're transmitting is straightforward enough. They might be producing such signals either to try and get in touch with you, which strikes me as a little bit unlikely. But, you know, they may be using radio for their own purposes to communicate with colonies or whatever. But where on the radio dialed the tune? How do we know? And we don't know. I mean, that's the bottom line. The most straightforward approach is just to, you know, search all frequencies that at least the ones you can build receivers that could tune in on those frequencies. That is kind of an approach that's been frequently used. But if you say, well, I can't monitor all the frequencies or if I can, it takes too long to do the experiment. Then you can say, well, if the aliens are really trying to get in touch, then they will pick frequencies that we can guess, such as the frequencies of the neutral hydrogen line, as it's called. This is a, you know, a natural emission produced by gas, hydrogen gas between the stars. And any aliens that do any radio astronomy, they will know that frequency. Their radio dials will be marked for that frequency. So, you know, if they're trying to get in touch, they might do something like that. But this is a whole industry in itself, if you will, trying to second guess how the aliens will produce a signal that we can find. And how important are exoplanets in this? Because obviously that is, well, in the grand scheme of astronomy, a relatively new discovery, you know, the last 30 years or so. Yeah, there's no doubt that if we knew or if we had a list of exoplanets 30 years ago or 40 years ago or 50 or 60, we would point our antennas in the directions of those exoplanets. But we didn't. We could do that now, and we do occasionally do that. But I think that the real importance of the discovery of exoplanets is not to give us new targets to look at. It's simply the statistics of that kind of phenomenon. How many planets are likely to be out there? What fraction of stars, at least stars that are somewhat like the sun, have planets? And you know, what fraction of those planets are somewhat like the Earth? In other words, having liquids on their surfaces of water, whatever oceans, atmospheres, all the sorts of things that might cook up some interesting aliens. And that's really astronomy. And that field is, you know, obviously more advanced than it was in 1960. And it's estimated, I saw this estimate at least, that maybe one out of every three or four star systems whose stars are somewhat like the sun has a planet somewhat like the Earth in terms of size, mass, and so forth, and temperature. And okay, that means that there are literally many hundreds of billions of Earth-like planets out there just in our galaxy. And that's where you would presumably start. And so finally, what excites you most about this work? What would you say are the next steps for the field? Well, I think that what excites me about this is that we happen to be living in a kind of special time. This is the first time in the history of Homo sapiens, which after all is, you know, measured in millions of years now, I guess. But this is the first time that we've had the technology to establish some sort of communication. If not that, at least, you know, discovery of other inhabitants of the universe who are as clever as we are, or maybe much more so. I think that, you know, 100 years from now, or maybe 200 years now, well, whatever, the history of humankind will be defined by the period before we found the aliens and the period afterward. Thank you to Seth Shostak. So Becky, where are scientists looking for signs of extraterrestrial life? Where could life flourish? Everywhere? Is that the kind of answer for where we're looking for? Down, everywhere. Down, down. Yeah. Seriously though, like as Seth touched on, right, you've got various different sort of like focuses going on, like within the scientific community. So you've got specialized missions that are aiming to explore the solar system that are focused on finding, say, microbial life on like Saturn or Jupiter's moons, like you've just got the Aeroclipper mission that launched at the end of 2024, or you've got like the Dragonfly mission to Titan, that's that upcoming mission to send a little like drone around the moon of Titan, you know. So there's lots of missions in the solar system going on, and obviously you've still got like, you know, the sample return missions from Mars, for example, where it's drilled for rock and we're hoping to bring them back to Earth, and we're going to try and find signs of life. You've had all of the asteroid return missions as well, right, like Hayabusa and Osiris Rex, things like that. Then you've got the search for what's known as biosignatures, so like biological signs of life. And in that aspect, like the focus is on the atmospheres of exoplanets, so planets in orbit around other stars, and we're doing that with the likes of JWST, for example, right, JWST in the infrared light that it looks at, in the infrared parts of the spectrum, you see things like, you know, water and methane and calm dioxide and things like that. And so what we're looking for with that is that the light from a star is passing through an atmosphere of an exoplanet, and there's molecules in the atmosphere that have absorbed some specific color of light. And if it's missing in the atmosphere, when we look at it, we're like, okay, that molecule is present. So we're looking for a molecular combination of molecules that only the chemistry of life could produce. And then obviously combining that with the right, you know, the conditions for life in terms of the planet size. So you have the right kind of like, you know, mass and size to give you that this gravity, you know, that wouldn't just squish you on the planet or you wouldn't float off. And of course, the same, the distance from it starts that it would have like a, you know, a temperate atmosphere for life to exist on. And then of course, you've got projects like SETI and also Breakthrough Listen as well, that keep an eye on the sky for these weird signals that we can't explain that could quite literally come from anywhere that could be some new astrophysics object that we've never, you know, observed before, or could be aliens, or could just be interference from something on Earth that we didn't realize where it came from. But this is the stuff I love. It's just like, it's the what could be. And that just sparks something which are like, this is really exciting. So let's talk about Breakthrough Listen, actually. So this is a project from the University of Oxford. So these are your colleagues. So what are they working on? What's their approach? Yeah. So I mean, the Breakthrough Listen folks are brilliant. They're doing targeted searches, so in both optical light and radio light as well, for what's known as technosignatures. So I mentioned biosignatures before, like a biological sign of life would be like a molecule, you know, some chemistry biology that's going on. Technosignatures mean like a technological signature, right? So, you know, some sort of radio signal, if you think about like on Earth, right, you know, in the times that we've been communicating, sending, you know, radiosignals, TV signals, communications, they're all done by radio light. And we've just been sort of broadcasting that into space since what, the 19, like, we're here, we're here. Exactly, right? So we're looking for that kind of technosignature, a sign of an advanced civilization, if we can be arrogant enough to call ourselves an advanced civilization. So what Breakthrough are doing is, you know, instead of waiting for something to sort of just go back and then look for it, they're doing like a few comprehensive, like targeted surveys. So first of all, they're keeping watch basically on all the stars within a hundred light years of Earth, like in great detail. Just to check, you know, because like we aren't putting out specifically strong radio signals, like all the time as like a beacon, you know, gone to all the beacon, we're over here kind of thing. So, you know, it's whether something would be quite faint or if, you know, all of a sudden, the civilization on that planet would be like, hey, should we send out a big like we are here signal? Is anyone going to be listening? You know, we just want to make sure that those are watched kind of thing and doing it for the hundred closest stars. It makes sense, right? Because if, you know, we were going to find anything, those are the only ones that we'd have a hope of having a very slow one way conversation with because of the distances. Very very slow two way conversation because of the distances. They're also, though, surveying the million closest stars to Earth as well. Obviously not in as great detail. So as in when I say detail, I mean, like not as great a cadence. So like, obviously, you can't keep an eye on all a million at once. You sort of look at a few and then come back to the other few and a few days later and stuff like that. So you don't have quite have the same sort of time coverage as you do for the closest 100. And then also they're doing a survey of the hundred closest galaxies as well to keep an eye on those in case, you know, they didn't find anything in them as well. And so they're doing all that with like, you know, like the big classic radio dishes. You've like got Green Bank in West Virginia. You've got the big parks dish down in Australia as well. That's absolutely massive. But they're also using like the big arrays of radio telescopes to like me cap down in South Africa, as well as like a precursor to the big square kilometer array that's coming very soon. All the radio astronomers are very excited about. What it means is that breakthrough have huge amounts of data, like literally daily they get terabytes worth of data. So to do this, like they're using a lot of like advanced machine learning and AI techniques to sift through the noise and identify any potential signals that might be of interest, which obviously is very useful for the search for techno signatures and extraterrestrial life, but also for anything else in astrophysics as well. Right. This is a lot of the techniques in that field. But what it means is that a lot of the people that work on this and who are in the breakthrough listening collaboration tend to be experts in lots of different things because they don't know what they might happen to find and what might pop up. Right. You know, the hope is a techno signature, but more often than not, it might be some weird pulsar or a supernova or unexplained object that they had to investigate further and explain and explain why it's an astrophysics object and not the techno signature that they were looking for. Right. But obviously the data they do collect is, you know, for targeted techno signature search and, you know, they're looking for things like say you have a planet in orbit around a star that's giving off a radio signal. The way you might actually find that is because the radio signal drifts as the planet orbits the star. So as it comes closer to you and then moves away again, you sort of get this, like, you know, a Doppler effect, like an ambulance siren where it's like, that's kind of like what? That's what it's like. That's what they're searching for with radio, like, essentially. But yeah, all sorts of things pop up in the process. So it's a really fun team, I think, to be part of their really great bunch of people. And yeah, the you never know. Yeah. Five when you go in their office, they're like, oh, this thing, you know, yeah, it's very fun. Oh, I love that. And I suppose, as you say, like, if you're scanning that that much and you're looking for all these different things, can that data then be used for other things to look at other astronomical objects? And, you know, we've got the data, so may as well, multi-purpose use. Yeah, exactly that. Yeah. And I think that's what's so great. And all of their data is very much like they work on like an open data model that's just available for the whole community as well. You know, it's very much kind of like nothing's behind closed doors. So it's a really cool initiative. So we've already heard about different approaches and different institutions involved in the search for life beyond Earth. But what type of signal are we actually looking for? And how would scientists distinguish between some sort of communication from extraterrestrial life and all the other signals always aiming to space? And what is the protocol if we find a signal? That's what everyone wants to know. Please help. Help. Break glass. These are all questions that Dr. John Elliott from the University of St. Andrews ponders on a regular basis. He's co-founder of the UK SETI Research Network and is the coordinator of the SETI Post-Detection Hub. Post-Detection Hub, I love that. I know, I know. Go get the PDH. We finally got a signal. Yeah, basically, he's the man with the plan. If we ever find a signal, failings. We use the SETI acronym at the beginning of the post-detection hub because it is the recognizable acronym for the search for life out there. But if you restrict intelligence just to something like us or beyond, then that really removes what we're also trying to do. And they look for life out there of any type. And actually, intelligence within life was displayed in our earliest microbes because it would use intelligence to avoid harmful environments. So, you know, it's a dimmer switch. Intelligence is a dimmer switch, I would say. And it started very early and it took three billion years to get a brain. Not that we've done a lot of great things with it, but one day. But SETI themselves, yeah, looking for technology, looking for and listening for, of course, evidence of technology and a signal is the prime example of that. So the scenario of us hearing a technological beacon or even a message through a way of an intergalactic email or a radio broadcast are the things we're really looking for. And so how do you look for them? How do you find that intergalactic email? I like that. We've been listening across a range of frequencies, but the thing really is that we've been listening out there for a signal that is like our own radio technology. It's tightly focused. It's only off just a few hertz bandwidth. It'd be reasonably powerful. That depends on how far it's been coming, of course. But our signals for radio, as you would typically sort of listen to a radio, especially an old fashioned radio with the dials on, then you'd be sort of scanning across the different frequencies to try and pick up a radio program. And you'll be getting a lot of static, a lot of noise. And suddenly you get this sort of squawk or this sort of sudden sound. There's much higher volume and you're getting something recognisable out of it. But how do you decipher any sort of communication? Because there's lots of different ways that that could work, I suppose. Start with what you know, what you can actually look at. Hope for the best. Yeah, it's not far from the truth. With my research going way back over a quarter of a century, I've been playing with this and looking at different human languages. I've analyzed over 60 that really represent all the different ways we communicate or have communicated over our history. So even the hieroglyphs are in there from ancient Egypt. So the different forms and ways we've written down our communication. So for the intergalactic email, I get in my best stab at being able to identify communication in its written form, but also audio and looking then beyond just even human communication, but into the animal kingdom like dolphins, birds, whalesong, these sort of things. And is it by looking at the audio of that you can see sort of patterns and things like that, because as an audio editor, if I look at a waveform, if someone says the word, um, I know what that looks like. So is that is that sort of a similar approach that you sort of can look at waveforms and start seeing the patterns and seeing if it is what I suppose irregular, is it is it something like that rather than like if a pulsar is going off and that's kind of a regular pattern. Is that what you're discounting? Yes. Yeah. The first thing is that we've picked something up and it's all that's interesting. Now we've got to filter out either just random noise or natural phenomenon, like you should say pulsars, quasars, anything that the galaxy, the universe may throw at us as a natural phenomenon that really we're not interested for this particular purpose. We're trying to find something alien made or human, you know, like human. The structures that comprise such communication is the thing I've been looking at. So whether it's in the audio, so whether it's our animals, dolphins, you know, this sort of thing, or all the different ways humans have put it together, it's become a template for the starting point of what communication could look like and how we could unpick it. It's the structures, the patterns and how they interrelate is the important thing. If you just think about you're in a room and you're the only person that speaks English, but everybody else in there is speaking a language you do not know, but you understand that they are speaking language. You could even understand that they're telling a joke. It's the rhythm, the structure, a lot of things in there. Underly what I'm talking about, about what communication really is and how it's put together. And then it's doing the reverse and unpicking it from those understandings. Yeah, it's fascinating. But as we've touched on, there is a lot of noise out there from other astronomical objects. So what is the process of kind of filtering through all of that? Yeah, so say we pick up the signal, we've got to first find out where we can pick the patterns, all the things that make up the signal, where they put together, where they're encoded, laboriously going through all the different possibilities until you actually have an indication that you've found the patterns if they exist. Now, I don't want to get into the maths complicated, but there is a way of having mathematical models and algorithms in there that I've developed or extended from other types of models that are helpful for this purpose. So we do all that, we go through all the number crunching. And if the patterns are in there, the elements that actually form these patterns will find them. And then it's looking at the relationships between those patterns and how it's built up. If we find those and we find what I would term internal structure, now we're getting to a phase that actually is telling us that this is likely to be a message or a communication in there, something with meaning behind it because of the way it's put together. But what is that plan? If, say, we establish some form of communication, we find a signal and a sign of life beyond Earth, what is the plan? Because, OK, scientifically, it would be incredibly exciting, but it will have a huge impact on society. Surely it's almost you need a global collaboration to understand what the process is. Yeah, this is where the SETI Post-Detection Hub comes in at St Andrews. I've been advocating that we have something meaningful like this as a what happens next provision. Yeah. And torn intensive purposes, apart from the odd sort of minor dable, something like this, it really hasn't occurred until now because it brings just about all the sciences together to understand how we can plan, strategize, look at all the different scenarios and then also at the same time represent humanity as a whole rather than just some sort of Western philosophy. So we have everything in place for just about any scenario we can think of when it happens. And do you think it's taken seriously by those in power? Like, are we ready? Yes, we're indicators of that in a year ago. There was an article in the UK government's magazine called The House where I was interviewed on this topic. And then very quickly, there was a question within the House on are we prepared? So immediately this members of parliament thinking, well, this sounds like something we should be involved in, especially when the expertise is centred in the UK. I've been in discussions with representatives from the Space Directorate on and off. I know we've had an election in the middle that sort of tripped things up a bit. But hopefully we will, like we need to do is to have dialogue, have open conduits with governmental stakeholders, decision makers all the way through to the UN, such as that when this happens, all our science, all our hard work that puts together the technology, whether it's computer programs, AI, all this sort of thing enabling us to do analysis through to all the societal legal preparation documents. All this, we can then advise the decision makers with all this knowledge and this preparation. Thank you to John Elliott from the University of St Andrews. He was very cool. I really like John. This is the Supermassive podcast from the Royal Astronomical Society with me, astrophysicist Dr Becky Sethurst and the wonderful science journalist Izzy Clark. That's me. OK, on to the questions. So Robert Facto Medi on Instagram asks, does extraterrestrial life have to be made of the same elements that we're made of? And Agelug said something similar, which was would extraterrestrial life be carbon based or not necessarily? Yeah, these are really good questions, Facto and Agelug. And the answers are complicated. And in truth, we don't quite know. So as it stands, life generally contains a lot of different compounds, a lot of the elements even in trace amounts. You know, if you want evidence of that, just look at the back of a multivitamin box and look at the number of things that are listed in tiny amounts. But to take the first one, there are experiments allowed to see whether life that we know about can work with things that are sometimes even toxic like arsenic. And so far, it doesn't really seem to be the case. So, you know, there was some work done on whether a bacteria could take up arsenic. And then it turned out whether we're just tolerating it, you know, not dying was the kind of result. And they're up. Nevertheless, they persisted. Nevertheless, they existed. Yeah, but it wasn't like going to take it. So that's, you know, so there is work going on to try and do that, but only with life that we've got here on earth. And there are obviously also bacteria that can tolerate things like sulfuric acid, for example. So and then there's speculation on what life could use and particularly other solvents. So substances that dissolve a solid liquid or gas. And the most common of those obviously is water, the one we're familiar with. And on places like Saturn's Moon Titan, the idea is, you know, you could look at something like ammonia in that regard, because that's there in liquid form. And if some life could use it as a solvent, and that would open it up as a kind of very exotic habitat, you know, one that operating at minus 180 degrees C. So, you know, really a very, very cold environment. It's like the East Coast of the US, right? Yeah, yeah. Well, that's going to say that, well, yes, this is the better. Yeah, but exactly rather colder than we've had it recently. And as for not using carbon, well, this is this is a sort of mainstay idea. It's been around for a long time. And the most popular idea is silicon, because that also forms quite complex molecules. However, some of the evidence against that is at least in our setting on Earth. It's silicon is really common. There's 135 times as much silicon as carbon on earth in things like sand, for example. Life doesn't really use it. And that's probably because the carbon based compounds are more complicated. You can develop more complicated molecules, which is good for life and more stable in the presence of water. And the kind of temperatures you have here on Earth now. And the other idea was, well, if it does exist, then it might get out, competed out, evolved by its carbon based counterpart. But the exception could be if you say you had a really high temperature world where silicon molecules might do better because they're more stable. So say if it was 300 degrees or 600 degrees, that, you know, they might do better in that environment. And it's really very much a kind of science fiction mainstay as well. It's I remember it's been back in the 1960s. I don't remember it being transmitted, but one of the episodes in the original Star Trek series has exactly that premise, you know, life existing based on silicon, very, very hot. And it's really exotic. We simply don't know. But people are asking the question, probably it's harder to make life out of something like silicon than it is carbon, just because the chemistry. This question pops up for me all the time when people ask about like J.D.R.S.T. search for life with those biosignatures that I was talking about before. People were like, but why are we looking for biosignatures like water and, you know, methane, ozone, it could be very different to life on earth. And I'm like, yeah, but we, you this it could be anything like we don't know. That's the point. So that's why we look for what we know, because we have no idea what it could be otherwise, because we've never been able to, you know, I just said, like, construct any life made from silicon or get stuff to survive in any other way. So yeah, absolutely. And Becky, Leif Candlecoe asks, is there a possibility that in the past Venus developed life? I mean, never say never. I don't think we're going to hedge our bets. Yeah. Like, I don't think we can fully rule anything like that out, because if you think about it, Venus is technically on the edge of like the habitable zone, right? The Goldilocks zone around the summer. It's not too hot, not too cold for life. And Venus was once thought to have had oceans of water, which if we think about its history of life, then that's where we think life started on earth as well as in is in the oceans. Now, obviously, since then, Venus doesn't have oceans now. Venus was thought to have gone through a runaway greenhouse effect, right? The oceans evaporated, that exacerbated the greenhouse effect with all of that water vapor in the atmosphere as well, trapped a load of energy from the sun, warming the surface of the planet to a very toasty four hundred and sixty four Celsius. Now, obviously, those conditions are incredibly extreme for life as we know it anyway. However, you know, we have seen that those little tardigrades, the little tiny micro animal water bears that are absolutely adorable, you know, like a tiny bug, they can survive decades in extreme conditions, right? And they've even survived when they've been exposed to the vacuum of space as well. So in the words of Jurassic Park, life finds a way, which is what I don't want to say. You never say never. Now, we have never found any evidence that life exists on Venus, though, right? At least current life. There was that result of phosphine, so pH three, ammonia and H3, but not nitrogen with phosphorus. That was found in the atmosphere back in 2020. If people are cheering them, hazy days of lockdown. I think that eventually people concluded that was, you know, very much unknown chemistry and was not going to be life. There were some questions raised about whether that detection was even there. But I think people have agreed now it is actually there. But that raised a lot of questions about, OK, the venerary emissions back in the 60s and 70s, Divina's. Maybe, you know, they didn't follow a lot of the decontamination protocols necessarily that are as strict today. You know, they had some, but they weren't very strict. And so, you know, have we perhaps polluted the atmosphere of Venus with sort of Earth life is a question. As for life in the past on Venus, which I think actually was the question that Leif asked, I did find a paper from 2023 by Warren and Kite that looked at this by modeling Venus's history. And essentially what the authors concluded was that at least for 70% of Venus's history, it was definitely not habitable to life as we know it. So I think the question is more of like, OK, whether in the other 30% of Venus's history, there was enough time for the sun to settle down after forming, first of all, and then life to develop because it is a very slow process, as we know on Earth, it took a very long time. And so, you know, it's just whether there was enough time on Venus before the runaway green house effect happened and it made it what we think, you know, is inhospitable to life or not. And I think that's, yeah, exactly. I think it's a really, you know, the point there is people look at extremophiles and they say there's life in these very extreme environments, but but they probably evolved from a more clement environment. You know, they didn't start off in this incredibly toxic setting. You know, you sort of imagine that life was it was driven by those extremes rather than rather than emerging there. So I think that's the really complicated questions. You know, if there were life on Mars, was it was it panspermia? You know, was it meteorites throwing it around the solar system? Or how did it get there in the first place? Did it develop there or not? Or did it develop on somewhere else on Mars or Earth and get carried there? Just don't know. Yeah, that's always the thing that fascinates me the most, Robert, like when we talk about does life exist elsewhere in the solar system? Is that question of if we do find it somewhere else? Does it look like Earthlife or is it completely different? Because if it looks like Earthlife, then that suggests that we have had a common origin like panspermia, this idea that life was seeded by life on asteroids or something like that. Or if it looks really different, then that means that life can start in two separate places and evolve completely differently. And all you just needed was the ingredients and to turn the oven on, basically. Yeah, but on that point of decontamination, you know, I think that's a really good point for when there's all this talk about what we do with Mars. I think it's like, is it just a pristine little experiment that we shouldn't go and grabby hands all over? I just think we please not send you a smart. Please, we're full of germs. So exactly it. Yeah, sending people to there. You can't decontaminate people. No, no. OK, Robert, we've had an email from your neighbour, Ben. And he says, what are your thoughts on intelligent life at the micro dimensional Kardashev scale? So I have to admit, I hadn't heard of this scale before. So it's a method of measuring a civilisation's level of technological advancement based on the amount of energy it's capable of harnessing and using. So it's a measure that was proposed by Soviet astronomer Nikolai Kardashev in 1964. So over to you, Robert. Well, well, thank you, Ben. And this serves me right for sharing our show on our neighbour. What's that? My name is. I love that you do that. That's so good. That's so nice. Trick trickle audience growth, you know. Yeah, so well, anyway, thanks, Ben. Yeah, it's the idea. So the idea of the macro Kardashev scale, the one you want to mention, there is is that as civilisations develop, they're able to able to use more and more energy. So type one civilisation can use all the available energy on its planet. A type two can use all the energy available in its solar system. And this is where you come to those sort of megastructures like Dyson spheres, big things that basically envelop a star and gather all its energy. None of them we've actually found, of course. And then type three, Thierresky could use all the energy available in its galaxy. I love that. Just be like, oh, I think there's a supernova going to go off in five years. Shall we go? Just go and mine that. Yeah, yeah. Yeah, I mean, you know, wildly speculative. But it's also seen as quite an old way of thinking in a sense now, I think, because generally we talk about technological development using less energy quite often or more efficiently than more. So and and Carl Sagan also refined it and put a sort of scale in place. You know, scientists think we don't want to three one steps between them. And on that measure, he assessed humanity being a type point seven civilization, just just a reference. And then there was a Sussex physicist, university, a Sussex physicist, John Brower, who died a few years ago. And he proposed type four, five and six civilizations that could basically draw on eventually the energy, the whole universe. And, you know, Frankie, you start to look a bit like a god, given what he was suggesting. And he also talked about this micro dimensional Kardashev scale that Penning was referring to. And here you've got the idea that civilizations start by making quite big things like buildings, type one minus. And then they work all the way down through the system, through genes and atoms and manipulating those and eventually subatomic elementary particles. So things like quarks and protons and neutrons in the nucleus, the nuclei of atoms. And then, you know, leptons, electrons. So and those are type six minus and then the most advanced, which I think he called type omega minus could even change the fabric of space. I mean, this is this is crazy. Well, I don't know about crazy, but it's certainly, you know, very, very speculative science fiction staple stuff again. So to turn to Ben's question, I think we're basically further along the micro dimensional scale than the macro one. And I guess, yeah, it seems. Celebrate little wins exactly. Yeah, but they're good ones, right? So it also seems to me philosophically better to work on lower energy processes rather than always envisaging ever greater consumption, which, you know, which doesn't have a happy history, right? You know, burning all the oil and gas on earth is not a good idea. And I sort of hope naively and that advanced civilizations do these incredible things, but they minimize the impact on their surroundings. And I guess, you know, the only caveat is that might make them really hard to find. Because if you're doing it on a very sort of, you know, leave no trace basis, the idea that you're you're doing amazing things, but you don't want to impact the wider universe of the planet you live on. Maybe that's going to make it much harder to find you as well. Who knows? I'd still rather that situation. It's not just life, just like tramp around. Yeah. On a less philosophical note than that, when I first started reading about this and started looking into like micro dimensional scales or micro scales, I was like, the borrower's. Are we talking about borrower's building little mini cities? Yes. OK. OK, Becky, very emergency says, what are the odds there's extraterrestrial life that we just straight up can't detect, whether that's microscopic or due to a dark atmosphere? Oh, they're so high. So high, right? I mean, we just talked with Robert right about, like, you know, life that isn't leaving a trace. There's that option. But there's also, you know, not just life that we can't detect, but life that we can confuse for something else or that all the signs of life are there, but we still can't rule out that it's basic chemistry that's going on instead. Like, like picture the scenario, right? We find an earth like version 2.0, right? It's the same size as earth. It's orbiting a star like the sun at a similar distance, getting the same kind of amount of energy. And then in its atmosphere, we find that it's got the same oxygen to nitrogen to ozone to water ratio as earth's atmosphere, maybe with a little sprinkling of ammonia and phosphine and methane and carbon dioxide and all of the byproducts of life on earth. How can we be sure we've actually detected life without actually going there? Right, we could have already observed a planet with life, but not with the right instrument or the telescope to pick out the feature that we need to say that life is there, right? There could be a whole host of these unknown knowns just sitting in our data archives, but like we don't know about them. So I think there is an incredibly high chance that we just straight up can't detect it and in high chance that maybe we have even looked at something that does have life, but we don't even know about it, right? Yeah. And that makes me incredibly excited. And I get goosebumps just thinking about it. Oh, same. Same. But we don't know about it. So. No. It sucks to be honest. OK, thanks everyone. And if you want to send in any questions, please do you can email podcast at ras.ac.uk or find us on Instagram. It's at SupermassivePod. So, Robert, as usual, let's finish with some stargazing. So what can we see in the night sky this month? Yeah, what was still in the situation? Winter constellations are still very, very dominant or summer constellations if you're in the Southern Hemisphere. So you've got Orion and the winter hexagon of bright stars around it and they're good throughout the evening at least. And if you follow the belt of Orion down or up in the Southern Hemisphere, you come to Sirius, which is the brightest star in the whole sky, only eight light years away in Canis Major, the great dog. And it twinkles violently usually because it's low in our atmosphere. And if you look at it, you won't see through a telescope, it's like looking at a bright star. But what you do really notice is this lovely rainbow of colors from the shimmering effect. So even though the star is actually white and above that, you've got Prasine and Canis Major, the little dog and the highest still. You've got Gemini, the twins and three targets there are things like Castor, which is a system of six stars that you can see three of those three of the pairs with the telescope and the nice cluster, Messier 35. But what people are talking about with quite a bit of hype is this so-called planet parade. Now, these things happen quite a bit. If you have a memory, you'll remember those, you know, quite a lot of years. These happen and not that unusually, actually, this is happening because most of the planets are in the solar system on a similar side of the sun. So they're all visible at the same time. And actually, that's not happening on any particular date that was mentioned in 25th of January. But rest assured, you're hearing it after that. But it doesn't matter because the planets are still there. And they're actually visible over some weeks, if you're listening to this in February. And it's possible to see Venus, Saturn, Neptune, Uranus, Jupiter, Mars moving over from the southwest to the east in the evening sky. And, you know, that's not their order of distance in the sun. It's just how they appear strung out across the sky, but it's not reflecting their distance in the sun and Uranus and Neptune, their distant, faint worlds until you need at least really a pair of binoculars or a moderate telescope to see them and certainly to see them as discs. But Mars is really good at the moment. Even though it's not that big with my little telescope, I could see the polar cap quite easily. It's not too bad at all. Give it a give it a shot. I mean, you know, I think just because it's high up in the sky, where as quite often when we see it, when it's close to the earth, it's in the low down in the southern sky. Now it's pretty good. Saturn is almost edge on, barely visible ring right now. In March that will be edge on. Venus is a really beautiful crescent getting thinner and bigger as it gets closer towards the earth and Jupiter's got its weather systems and moons. So all of these things are great. And at the end of the month, Mercury will join in as well. It'll be low down in the southwest after sunset on the 25th and 26th of February near Saturn, and it'll be really well placed in the first half of March. It's quite hard to see, but just occasionally a few times a year. It's not bad. I don't have a clear enough horizon here. Like I think if you've got any sort of house trees on the horizon, try it. Exactly right. Exactly right. Norfolk and it's just, you know, flatlands. Yeah, or get high up. But it's easy than you think if it's actually there. The one thing I should mention as well, if depending on when you listen to this again, there is national astronomy week running from the first to the ninth of February and a lot of amateur astronomy groups and public observatories and so on are running events where you can actually go and look at the planets because the whole theme is called chasing the moon and it's tracking the crescent moon as it goes from one planet to another from the first to the ninth of February. So do have a look on the site. It's astronomyweek.org.uk has got a long list of events. Oh, nice. I'll put that in the show notes as well. So people can find it there. The funny thing about this whole planetary parade that's been like so hyped in the media and I get why they're hyping it because it's fun news. Yeah, the caltis is going on. But like it is this weird date that people have given to it. Like I've seen the 21st of Jan. I've seen the 25th of Jan. And I might look if you've been looking at the sky through December and January, the planets have been there. Yeah, exactly. You can see with your eyes. They've been there the entire time. Yeah. And they're going to be there the entire time in February. The only thing that I could find, Robert, and I don't know if you've seen this to the only thing I could think of as to why that date has appeared out of nowhere is that on the 21st is when it gets to a half moon and it's waning the entire time and by the 25th it's near a crescent. So it's dark. Is it the only thing that I could think of? Like it was like, okay, the moon's not going to be in the way for you to see the planets. But that was it. Like there's nothing special about the 21st and the 25th. So if you keep reading all this media hype, just go for it. And that's the thing. And it's here for a while. It's not like it's on a date. And then you're not going to see it. It's like, no, you can see them now. And I've actually really enjoyed it. It's been lovely. It's beautiful, exactly. And I think this is like when sometimes I get phoned up by journalists, they think it's like, well, will we be able to see it in, say, Yorkshire? And I said, thinking, well, yes. Anywhere in the world. Just exactly. Just as you can in, say, Sussex or Australia. Yeah, it's like, exactly. I like that. It's like, oh, is it rare that they're all in a line? And I'm like, no, because all of the solar system objects take the same path through the sky all the time. Exactly. They're always in a line. If you have two, three, four, five, how many of them are always in a line? Yeah, but at the same time, I do think if you're not familiar with this world, if you don't engage with it, then you are going to have those questions. And I think that's fine. It's each fine. Because for some people, this is just so new. And I kind of like that it gets people talking about it. And you never know. This might be the first time that someone's come to it. And then they're like, well, actually, I remember back in 2025, you know, maybe this is their starting at stargazing. But yeah, fair enough. I guess I covered it from a pessimistic viewpoint of like, if we keep hyping this stuff up and people go outside and they're like, and it like they'll get almost disillusioned with it. So that next time there is a really cool thing, you know, and they're not bothered or something. Yeah. I mean, you're right. You see, it's OK to ask the questions. I think it's just that in the coverage, let's be, you know, it's a really nice thing to flag and to say, look, this is happening this year. By the way, it happened last year and it happened a couple of years before that and so on. But just to put it in those terms. Yeah, I mean, it's very common. It's and, you know, it's also the fact we've got all of them now. You'll remember, I think if you go back a few months, so hardly any planet's visible. And that's because they happen to be all the same. Exactly the same side of the. So and they'll all drift around and Venus, Mars and so on and Mercury will move pretty quickly around the sun. So yeah, in a few months time, this won't happen, but it will come again. I'm losing Saturn soon as well. We're losing Saturn's rings as well. Temporarily doesn't pop out from the side of the sun until May. And I'm like, oh, what are you going to do? But the rings will come back then. So you've got that. Yeah, I'll get me through winter. Well, that is it for this month. We'll be back next time with an episode on sample return missions. And there'll be a bonus episode taking on more of your questions in a few weeks. As always, contact us if you try some astronomy at home. It's at SupermassivePod on Instagram, or you can email your questions to podcast at res.ac.uk and we'll try and cover them in a future episode. But until next time, everybody, happy stargazing.