Why Have We Not Found Any Aliens? - with Keith Cooper

[Music] well thank you everybody for coming to listen to me talk if I seem a little bit nervous this is the hallowed grounds where all the famous Christmas lectures have been held including as Martin mentioned my idol Carl Sagan Carl Sagan was one of the leading rights in in SETI and it's a real privilege for me to be here especially as it's something very dear to me a book I've been working on for quite some time and a subject that I just find to be completely wondrous and amazing which is SETI the search for extraterrestrial intelligence so what is SETI it's not flying saucers or UFOs or abductions or anything like that it's a scientific search for intelligent life out there somewhere among the stars we don't know if it's there but the only way we're going to know really is to look and see if we can see any evidence of their presence there and you know many of you will have seen the film contacts starring Jodie Foster based on the book of the same name by Carl Sagan and that's all about receiving a radio signal from from outer space from an advanced civilization and Jodie Foster gets to go and meet them briefly and you can see there she's listening to signals from outer space on our headphones with the radio telescope in the background I think in the film she's kind of sat on a car bonnet in the desert by the radio telescope just chilling out listening to these signals from outer space it's not quite as glamorous as that unfortunately computers do most of the analyzing of the signals but by radio you know we're talking about an advanced civilization maybe millions billions of years older than us why would they use something as low-tech as radio surely they'd use some kind of hyper dimensional means of communication well maybe they do but we can't really detect that because we don't know what that is so first of all we're a little bit limited to detecting things that we know about the second reason why we use radio is in 1959 to astronomers Philip Morrison who I believe has given Christmas lectures here and Giuseppi cocconi they wrote a very famous paper in the scientific journal Nature and they were investigating what the best means of transmitting a message to nearby stars would be and so they looked at the electromagnetic magnetic spectrum of lights and things like x-rays and gamma-rays and they decided that radio would be the best for several reasons now you have to understand back in 1959 radio was a maturing technology had developed a lot in the Second World War everybody had Wireless is in their houses and listening to BBC one and things like that and a new frontier was opening up in astronomy of radio astronomy and radio is really good because as you can see this is a snapshot of the Milky Way part of the Milky Way galaxy he loads loads of stars and some nebulae in there you see this big black band running through the middle and that's all dust it's all interstellar dust space isn't a vacuum it's filled with all kinds of stuff and you can see that the dust airs it's black it's blocking out the light from the stars behind so if you try to send an optical signal of some kind it wouldn't get very far before it's absorbed by dust but radio waves pass straight through the dust like it wasn't there so you can detect signals from much further away and to give you an idea of how far away we can detect radio signals many of you will be familiar with this image it was released earlier this year this is the first ever image of a black hole it was taken with the event horizon telescope which isn't just one telescope it's a network of large radio telescopes all around the world working together and this shows the the hot disk of gas around the the supermassive black hole in the galaxy Messier 87 which is 54 million light years away and those radio waves granted it did take a lot of large telescopes to detect them but those radio waves have traveled unhindered throughout space 51 million light years to reach us so after Baconian larson published their paper this chap here Frank Drake he also came up independently with the same conclusion that wager would be a really good way of communicating between the stars and in 1960 in April 1960 he performed the first ever radio SETI search which called Project Ozma was named after the princess from The Wizard of Oz stories and he targeted two nearby stars Epsilon Eridani which is ten point five light-years away and Tau Ceti which is I think is about 12 light-years away so fairly close among the very first day he found a signal they probably sat back in his chair and thought cranky this is easy turned out not to be aliens it was actually a u-2 spy plane flying overhead it was top secret nobody knew about it at the time I think this was a month before Gary Powers was shot down and you can see here he's writing on on his whiteboard an equation and this is the famous Drake Equation what he's most famous for don't take it literally it is a way of well basically they were having a the first ever SETI conference at the Green Bank radio Observatory where Frank Drake worked in 1961 and Drake was put in charge of organizing the agenda I mean you thought cranky what on earth am I going to talk about I don't know anything about aliens nobody does so he came up with this equation as a way of just stimulating discussion about how many extraterrestrial civilizations may be out there and what factors may be involved in the likelihood of them existing and it's really fun to plug numbers in and see what kind of results we get so I've done that on the next slide so the first factor is the rate of star formation in our galaxy which is about one solar mass per year all that gas in the galaxy is converted into a on average one star per year the fraction of stars with planets well NASA's Kepler space telescope which you may have heard of it launched in 2009 went and retired in 2018 it was a space mission designed to detect exoplanets which are planets orbiting other stars and based on the system the statistics of the planets it found it scientists conclude that pretty much every star has planets and probably more than one there's probably more planets in the galaxy than there are stars which is quite amazing considering that in the early 90s we didn't even know if there were any other planets in this you know beyond the solar system so the next factor is the number of habitable planets per star well we can't have or maybe a rough guess of that because we know of a region around the stars called the habitable zone this is the distance from a star where temperatures should be just about right for liquid water to exist on the surface providing there's an earth-like atmosphere so there's lots of if buts or maybes there it's not necessarily mean that planets within the habitable zone are habitable so maybe we should look at our own solar system well we know earth is habitable cos we're here but are there any of the worlds in the solar system that could potentially be habitable and I think there is there's Mars we know we're looking for life on Mars microbial life not intelligent life but you know this could still be life there then there's Jupiter's moon Europa which is an icy moon it's covered by a thick crust of ice but below that ice is a global ocean and it's possible that conditions there could be right to support life and similarly Saturn's moon Enceladus also has a global ocean underneath the ice and could support life so I'm going to be really optimistic and I'm gonna say based on our solar system that four moons or worlds around a star can have life it doesn't mean they necessarily have life and that's the next factor the fraction of those planets that develop life well in our solar system as far as we know only Earth has developed life and similarly only earth has developed intelligent life and only Earth has life that is transmitting messages radio leakage into space the final factor is the most interesting I think the lifetime of a civilization that that sends signals into space so this isn't necessarily the lifetime of a civilization from you know its origins all the way through to is extinction it's just really talking about the amount of time that it spends transmitting into space although you would expect a technological civilization to be sending signals for most it's existence whether deliberate or just accidental leakage we've been sending signals into space for about a hundred years since we started started broadcasting radio hopefully we're going to be broadcasting signals for a lot longer than 100 years otherwise it means we've gone extinct other civilizations think for 10,000 years and million years even a billion years we don't know and as you can see on the next slide I multiply all those numbers and I estimate there are 100 civilizations in our galaxy right now and it's just a guess it nobody really knows but as you can see it gives you a way of considering the factors that are involved and you can also see there that the larger L is the larger the lifetime is the more civilizations there are and that's because the longer lived the civilization is more chanceries that it's going to overlap in time with other civilizations if you know if a civilization exists and dies out and then another civilization arises they're not going to detect the one that's died out so they need to overlap to be able to detect although of course distances in space mean that it could take many years for a radio signal to reach us we may detect a radio signal from a civilization that has already gone extinct so back to radio and this is a radio map of our galaxy and this has been imaged at the 21 centimeter neutral hydrogen lines so neutral had hydrogen atoms in our galaxy emit radio waves when when excited at the wavelength of 21 centimeters and this is mostly the wavelength that astronomers observe the the universe at because they want to study the hydrogen it's the most common gas in the universe the most come on Adam and maybe aliens will know that we're already going to be looking at the radio universe at that wavelength so they'll send their signals at that wavelength because we're already going to be looking so we'll see them and back in 1960 when Frank Drake performed project Ozma we could only look at one wavelength channel at a time we didn't have the equipment the technology to look at many more channels all at once today things are different we can look at billions of narrowband radio channels all at once so we can scan the radio spectrum so whatever wavelength they would be transmitting out we should be able to detect it and you have to understand that SETI it been looked down on back in that by the scientific community probably because there's a little bit of a snigger factor there people do think of aliens flying saucers little green men and for much of its history it hasn't really been funded very well miss scrimped and saved and in the early 90s it looked like NASA we're going to have a massive SETI project whether we're going to put millions and millions of dollars into it but at the last moment this got cut off at the knees by the US Congress that cancelled NASA's funding for SETI so ever since then it's been relying on donations and that means we haven't been able to do many SETI searches and those that we have done just look at a few stars now you might say well city's been going on for 60 years why haven't we discovered anything yet it's because we've only sampled a small portion of the galaxy let me make an analogy if you went to the seaside with a beaker of glass scooped up some water would you expect to find fish in it probably not that doesn't mean there's not fish in the ocean it just means we haven't sampled enough for the ocean to find those fish and it's the same with SETI we haven't sampled enough of the universe yet to find if there are any aliens out there but in 2016 this chap here on the left yuri milner he's a billionaire philanthropist he launched the breakthrough listen project it's a 10-year project at least where he's putting in a hundred million dollars over the course of those ten years and what's that going to do to SETI it's going to revitalize it it is revitalizing it right now before this we've looked at maybe a thousand stars in detail closely listening for signals from from aliens and when I say listening closely I'm talking about we listen for maybe half an hour with a radio telescope before moving on to the next one well maybe the aliens run a tea break or something and we didn't pick up their signal who knows it's not enough time to be sure whether there's anybody out there or not brick through listen is going to look at a million stars in close detail still only going to be looking for a half an hour or an hour at each star but still it's a huge both in coverage it's going to be performing surveys of the night sky sweeping across the sky listening for large beacons it's going to be scrutinizing the galactic center where we can see most of the stars in our galaxy and it's even going to be looking to distance galaxies in case there's a powerful beacon being beamed our way who knows we won't know unless we look so break through listen it's really changing things and that produces a lot of data you saw Jodie Foster with her headphones listen to signals from space well she can't do that with all this data that's part too much of it and to show how fast SETI has come since the early days now they use machine learning algorithms to search for patterns amidst the radio static there's a kind of an artistic representation of a I guess a robotic Jodie Foster with her with her headphones and the radio telescope in the background now this is our galaxy you can see the Sun we're 26,000 light-years from the center of the galaxy our galaxy contains 200 billion stars give or take that's a huge number of stars to search through so the odds are still against breakthrough listen detecting anything let's say we did the Drake Equation and came up with a value of 10,000 civilizations in our galaxy we'd still have to search 20 million stars before we found one of those civilizations on average Brickley listen is only going to listen carefully to a million stars so it's still not enough we have to be really patient doing SETI we could find a signal tomorrow or it may take 10 years may take 100 years maybe we'll never find a signal but we won't know until we look other any ways that we can improve our chances well we don't have to stick through radio I know what I said at the beginning about radio being really good because it can pass through all the interstellar dust but you know there are other means what if aliens are sending messages not by radio but by lasers in 1960 when Drake did his project Ozma the laser was just being invented when it was invented scientists at the time were they didn't didn't see what good the laser would do they thought it was a solution without a problem they said on earth we do do with the laser which sounds faintly ridiculous now because we use lasers everywhere in everyday life and this isn't a this is not a laser being sent into space with a message this is actually an artificial this this is the this is the very large telescope in Chile and basically they fire lasers at the sky to create an artificial Stan it allows the telescope to lock onto that artificial star and compensate for the blurring effects of the atmosphere you know how you see stars twinkle but it looks good so I thought I'd put it in now this is a serious laser this is the laser at the National Ignition facility at the Lawrence Livermore National Laboratory in California it has it reaches a petawatt which is thousand trillion watts so you know how many light bulbs could you light up with with that and what did they use such an overpowered laser far well they used it for nuclear fusion experiments so you can see on the lasers shining down and you can just about see an arm coming out from the bottom at the end of that arm they have fuel pellets and the lasers heats the fuel pellets to millions hundreds of millions of degrees to the point that the atoms within them fuse and release energy and it's hoped that by the middle of this century that we'll have nuclear fusion providing electricity to the National Grid we'll see but these lasers for perhaps a fraction of a second can shine brighter than the Sun which is remarkable so you can imagine pointing these lasers outwards into space and sending pulses containing messages and are we looking for them yeah we're looking for them and lasers have an advantage over radio radio suffers from what's called dispersion so as I've mentioned space is not empty it's full of atoms and molecules and particles and in particular when radio waves encounter electron particles the electron particles interact with the radio waves and cause the longer wavelength radio waves to be delayed so they arrive at their destination behind the shorter wavelength rate radio waves and then you know your message gets scrambled upon arrival which isn't great that does not happen with laser-light this been calculated that if we shined one of those petawatt lasers into space with a message by about a distance of a thousand light-years about 90 percent of that light would have been absorbed by dust so it's limited in range but can we beat that well yes we can because infrared can pass through some of that dust astronomers observe the universe in infrared to see inside dusty star and planet forming regions so professor Shelly writes we can see in the background here came up with the idea of building an instrument designed to look for infrared laser pulses she's holding a infrared detector there it's on the nickel telescope at Lick Observatory again she hasn't found anything yet but it's a new way of doing SETI we've only just started and perhaps she will space actually if we had an infrared satellite in space dedicated to looking for infrared lasers that would be more beneficial because our atmosphere does absorb some infrared light this is upon Lick Observatory up on top of a mountain so it's above much of the atmosphere but still unfortunally space missions are expensive so SETI I'm gonna get one of them just yet are there any other ways that we could search for life in the universe and indeed there is this is an artistic representation of an earth-like planet around another star and we can't really image these planets we don't know what they look like yet the way we that we discovered them mostly is through something called transits and here is a video so a planet will move in front of its star and it causes a dip in light and then when it moves away from the star the brightness of the star goes back up and is the the solar system roughly to scale a jupiter-like planet would cause a dip in lights of about 1% an earth-like planet much smaller would create a dip in light of about not point not 8% but our photometers that count photons from these stars are able to measure such minut dips in light and detect that the light curves as we call them and there's a real-life light curve of an exoplanet now what else can transits do well as a planet moves in front of its star some of the star light shines through its atmosphere and the atoms and molecules within that atmosphere will absorb some of that light and then we will look at the star spectra is some examples of stellar spectra when the molecules absorb the light they create dark absorption lines in the spectrum at specific wavelengths so if there's oxygen in the atmosphere that will cause an absorption line that's a certain wavelength similarly carbon dioxide or methane and we can then look for biosignatures gases that can be produced by a life and if we find them in certain abundances in a planetary atmosphere that might be a sign that there's life there of course it wouldn't tell us whether that life is microbial or animal life or intelligent life but would certainly know there was something there another way that we could look for alien life this is just an artist's representation of the of the surface of an exoplanet I believe this is Proxima B which is the planet orbiting the nearest star to the Sun Proxima Centauri just 4.2 light-years away but another way that we can look for for life is to search for something called techno signatures now this is this is the buzzword in SETI at the moment it was coined by when upset his most famous astronomers Jill tarter and techno signatures refer to evidence of extraterrestrial technology now technically radio signals and laser signals would count as evidence of extraterrestrial technology but so could in interstellar probe or maybe if they're mining asteroids that might reduce dust that we could detect or perhaps they like building things megastructures dyson sphere's is an artists representation of a Dyson Sphere this is a concept that has dreamt up by the famous physicist Freeman Dyson again in 1960 there was a lot going on at that time and he reasoned that an advanced civilization would want energy the same way that our civilization uses energy a lot now the Sun radiates out having 400 trillion trillion watts in all directions and only a small portion of that falls on earth so we only get a little bit of the sun's energy enough for life on this planet but advanced civilization may want more there may be hungry for more and then we want some more of that's solar energy so they could build a great swarm of solar energy collectors to surround the star and in the media this is often depicted as a solid sphere that would be unstable gravitational perturbations could pull it apart or send it spiraling into its star inside destroying it so more likely if aliens don't like doing this they would build a swarm of solar collectors or here we see interlinking acts not connected and that's much more stable and you might wonder well how would we go about building something so immense sighs well Dyson just casually said well we could just dismantle Jupiter I have no idea how we would dismantle Jupiter to get the raw materials for a Dyson Sphere but we don't have to we could bootstrap the process we could start building solar collectors now just a few of them and then the energy that those solar collectors collect could help go into building more solar collectors that collect more energy and so on and so forth we could gradually build it up and I always like to joke that to be you know the way that we you know leave construction sites have finished we'll look around the galaxy we won't find Dyson spheres will find Dyson Hemet Dyson hemispheres that never got finished being built now have we ever discovered a Dyson Sphere no but a couple of years ago we thought we may have so this is a light curve like the one I showed before on the animation when the planet transited is stabbed but you can see it looks nothing like that nicely symmetrical light curve in the animation this is I mean goodness knows what's going on here you know we've got dips of all kinds of different magnitudes and sizes there's no obvious periodicity which would expect from a planet in orbit so this was found by citizen scientists on the planet hunters website where the cause Kepler produce so much data astronomers had to enlist citizen scientists help go through it all so they started this website planet hunters calm you can still go on it today and they put samples of light curves on stars and you scroll through it and if you saw something that looked like a transit of a planet flag it up another professional astronomer would follow up now citizen scientists started finding really weird transits like this on the star kic eight four six two eight five two for some reason astronomers have a tendency to give stars and planets telephone numbers for names so this came to the attention of an astronomer Louisiana State University called Tabitha Boyajian she collected all the the data together and found that there were swarms of mysterious objects transiting this star didn't seem to be any rhyme or reason behind it at one point a quarter of the star's light was blocked remember what I said about Goethe blocking 1% so whatever was blocking the light was huge now the audience first there was maybe it's a swarm of giant comets each comets the size of a moon and you can see in this artist's impression how that could create weird dips the problem was we have no idea how a swarm of comets the size of moons could farm that would be completely beyond what we know so then it was suggested well perhaps it's aliens perhaps aliens have been building something in orbit around their stand that's what we're seeing this mega structure transiting its star and for a while this was actually taken seriously and it was really cool because that you know the public got enthusiasts through enthusiastic about it but so did the scientific community you'd expect them to be sniffy about it but they weren't it turned out in the end that whatever is causing the the dips is dust interstellar dust we don't know if it's an orbit around the star or whether it's just between us and the star we don't know whether just has come from so it's still a puzzle it's a fascinating mystery but it isn't aliens unfortunately but I think this and plus break from listeners really revitalized SETI for the public and for the scientific community it's in the news a lot more now people write books and and I think it's good news even though it didn't turn out to be aliens does that mean that we haven't detected any evidence whatsoever that there's life out there I wouldn't say that in 1977 astronomers in Ohio at the big ear telescope we're doing a safety experiment now you can see the telescope there at the bottom left it doesn't look like your typical radio telescope with a dish pointing up at the sky it's about the size of it's supposed to be about the size of three football fields and on the ground is aluminium plating that prevents the ground from absorbing the radio waves and you can see two walls on either side the wall on the right could be tilted to look at different heights above the horizon and radio waves would come down from space they would reflect off their tilted wall on the right reflect over to the wall on the left and then go into the two feedhorn so you can just see in the picture or you can see better in the picture in the background and that's where the receivers were and the telescope was fixed on the ground so it couldn't go on point at an object it had to wait for the Earth's rotation to work in its favor and to bring whatever objects it wanted to look at overhead and the object would move in the field of view and be detected by the receivers in the first feedhorn it would move a bit further across the sky and be detected in the receivers in the second seven second feedhorn and then to move out the field of view and there were no astronomers actually at the telescope doing this it was all automated in every few days and the Strummer our technician would have to travel up there and bring back all the data now back in 1977 they didn't have huge hard drives it was all printed out on that horrible perforated printer paper reams and reams of the stuff so just after the 15th of August of that year astronomer Jerry Amon went up to get the data and he was perusing it found something really odd something he'd never seen before is the part of that the printout with the with the signal I can see lots of numbers and letters there the numbers and letters denote the the strength of signals detected by the telescope above the background level so a number of one is one times stronger than the background level so the one two nine were background strengths one to nine times higher than the background and then the letters signified strengths ten are above so you can see there where he circled it so you have six I'm stronger then it got even stronger possibly as it moved more into the field of view of the receivers II that's 14 times stronger you thirty times stronger than the background so you circled it because this was the most powerful radio signal he'd ever seen he got Wow in the margin and the SETI legend was born the WoW signal now we don't know what caused it it could have been terrestrial interference maybe it was some kind of Astrophysical phenomenon may be a black hole swallowing a star a burst of radio waves its final death throes maybe it was aliens we don't know Amon for his part is convinced it was an extraterrestrial signal he's ruled out terrestrial interference and other things but we don't know until we detect it again we'll never know now we have gone back and tried to find it again but as I mentioned said he hasn't had much funding and searches have been scammed we have tried looked for an hour or two but we haven't detected and detected anything perhaps its psyche the signal is cycling around planets and will eventually come back to point at Earth sometime in the future we just have to be looking off to catch it or maybe it was just a one-off Astrophysical event that would never know what it was it's so tantalizing and so frustrating at the same time so that's kind of a quick potted history of city so far as kind of a racks to relative riches story with the funding now from breakthrough listen but in telling that story what I haven't done is really talk about the assumptions that we make in setting and how those assumptions affect our search and our likelihood of success now here's a secret don't tell anybody I don't know anything about aliens neither do you you know just as much as I do and together we know just as much as the professional astronomers because nobody has ever met an alien so how do we know what they might do well we can extrapolate from human civilization what would we do in the future if we had advanced technology how would we behave how is society going to change in some ways that's really good because allows us to look more closely at our own civilization and understand ourselves better but that also brings a whole set of assumptions about extraterrestrial life alien life may not be like us but we're kind of looking for something similar to us we're looking for human civilization modern-day civilization extrapolated into the future so what kind of assumptions is that great well we're looking for technological intelligence now we always seem to equate intelligence with technology as if one automatically leads to the other there's no evidence that that's the case we don't fully understand yet the origin the evolution of scientific thinking and technological thinking perhaps most life in the universe is like dolphins dolphins are intelligent but they're never going to build a radio telescope with flippers and you know studies have shown that perhaps most planets in habitable zones around stars could be water worlds maybe Dolphin life is prevalent and our kind of life isn't there could be loads of planets out there with the similar kind of life to dolphins we would not detect them because we're looking for civilizations that produce radio telescopes and transmit radio signals another assumption that we make is that aliens are going to be able to detect us that it's going to be easy for them to detectors or to transmit their own signals after all their advanced aliens millions or billions of years older than us surely there's nothing they can do nothing that they can't do rather could they really detect us through our radio leakage well this is a representation of our galaxy similar to the one I showed earlier and you can see inset in that box you can just see an arrow pointing to little blue kind of dots that dots is 200 light-years in diameter at the scale of the galaxy and that is the volume of space with which our radio signals have reached so far it's not a lot is it compared to the rest of the galaxy surface you know if there's a an alien over on the other side they're not going to know we're here but it's interesting to talk about our radio leakage because you've probably heard that aliens will know we're here because they can detect our TV signals but even if they were say 50 light years away could they really detect our signals could they be watching EastEnders well I'm skeptical about that and so incest you're stuck at the the SETI Institute he's done some calculations that this is the Arecibo radio telescope it's one of the biggest radio telescopes in the world it used to be the biggest but now the Chinese have the 500 meter aperture telescope in much bigger and but anyway szostak calculated that if we put another Arecibo on Alpha Centauri on a planet around Alpha Centauri which is this four point three light years away that Arecibo could not detect our radio and television signals there would be too faint would you kind of expect because you know when we broadcast TV and radio is intended for a terrestrial audience not an extraterrestrial audience so the signals are going to be pretty faint well what about an hour see Bo detecting another Arecibo if aliens had a telescope the same size as Arecibo could they detect transmissions from our Arecibo well just that calculated that up to a maximum distance of 400 light-years they could beyond that even our C Bose transmissions would be too faint and we have sent messages transmissions using Arecibo in 1974 Frank Drake as I mentioned the father of SETI he was the director of the Arecibo radio telescope and it just had a refurbishment is that big ball that you saw had just been we paneled and they'd added a transmitter and Drake wanted to play around with the transmitter so at the reopening ceremony he transmitted this message to the star cluster on the Left Messier 13 which is 22,000 light-years away now it's a little bit of a fool's errand because by the time our signal reaches m4m 13 and 13 is going to move it's orbiting the galaxy so it's not going to be there that's beside the point really so he created this signal in binary code intended for aliens to understand people here understand that not many not many so at the top we have those white dots they're the binary numbers 1 to 10 and they're meant to be used as a key to understand the rest of the message underneath there we have descriptions of the atoms hydrogen carbon oxygen nitrogen phosphorus which are the building blocks of nucleotides which in themselves are building blocks of DNA and RNA and you can see in the middle there this meant to be a representation of a DNA helix I'm not entirely sure how aliens are meant to figure that one out underneath there we have a stick figure of a human being probably the most recognizable thing in the picture we recognize it aliens going to recognize that that is a life-form that that is us and what are they going to think if they think that says so and there's the population of Earth at the time which is 4.3 billion underneath there you can see reputation representation of the solar system the third planet out Earth is raised above to try and signify that that's where the signal came from and you can see there's nine planets there because at the time Pluto was considered to be a fully fledged planet and at the bottom that is meant to be the Arecibo radio telescope so this brings up issues of its own in you know in terms of how will a Lian's be able to understand their radio signals but now there is a reason there's a squirrel there so the gist that I'm trying to get to is that it is difficult to transmit signals and it's difficult to receive signals szostak calculated that if aliens had a radio telescope oh the size of the metropolitan area of Chicago which is twenty five thousand eight hundred kilometres square then they would be able to tech detect our radio leakage hundreds of light-years away thousands of light-years the only problem is such a telescope in our economy would cost 53 trillion pounds no obviously aliens aren't going to have the same economy that we are then I've got pounds and dollars and we don't know what resources they would have exactly but the point is it's going to require a lot of effort and a lot of resources and all of energy to build telescopes to detect radio signals and more importantly to out messages of their own for us to hear and they don't just be in them at once if they want to be heard they have to beam them out constantly in all directions because they don't know where we are and that requires a lot of power now why should they do that probably got better things to do with their time than devote disproportionate amount of resources just trying to message somebody who might not even be out there they may never get a reply they don't know if anybody's out there just as we don't so what would prompt somebody to do that well in SETI SETI scientists think well aliens are advanced not just technologically but altruistically as well they're perfect beings they're going to be kind and welcoming and have all this pure selfless altruism so they'll be happy to spend all their money and all their resources to build radio transmitters really I don't think so in nature there are two kinds of altruism that are dominant so the first one is something called kin selection and that is why I have a picture of a squirrel so I've got two dogs and every morning I'd fridge through wet muddy fields with them and around this time of year squirrels are out in force hunting for nuts and other tidbits to take away to star overwinter and my dogs love to chase squirrels love it and every now and then you hear a school shout a warning from a tree or a branch or wherever presumably in school language it means run for your lives there's a crazy dog on the loose now that squirrel doesn't know any better it just thinks dog could be a predator so it's crying out this warning to its offspring to its nieces nephews run save yourselves and in doing so it puts itself at risk it reveals its location - this supposed predator why would it do that it's doing that because it's safeguarding its offspring its safeguarding its genetic information so it can still be passed on to future generations if they all get eaten by the predator because the squirrel didn't cry out a warning well that's the end of their lineage so Nature has this inbuilt mechanism to help us protect our genetic information and we even kind of do it you know if we have children there are things that we do unconditionally for them that we wouldn't do for other people because they carry our genetic information and we want to help them prosper another kind of altruism is called reciprocal altruism basically you do something for me and I'll do something for you and it's how much of the world works really and it's you know that's fine but could it work over interstellar distances could that kind of altruism prompt to civilization to throw loads of resource resources into building a transmitter to send messages out with the vague hope that maybe they'll hear back from somebody well possibly but distances and time spans of space kind of work against it they don't know we're here and even if we are here they may not get a signal back for hundreds or even thousands of years given the distances between us so I don't know I'm skeptical that that would work and this all works against SETI and our odds of finding evidence for extraterrestrial intelligence because if their signals are too weak or they deem it not worth the effort to send out messages we're not going to find them so some people have suggested maybe we should send out our own messages instead if they're not beaming messages towards us maybe we should be the ones to say hello and provoke them to respond and this has caused great arguments in the SETI community because some people think it's dangerous we don't know what is out there maybe what is out there is malevolent maybe it can be a War of the Worlds scenario or something like that and I think that's a straw man argument because the distances involved would mean that it is unlikely they could mount an invasion expedition not the interstellar travel is impossible so here we have an artist representation this this is URI Milner's other project that he's doing breakthrough starshot he wants to launch a fleet of tiny spacecraft called star chips and beamed them Rag them on laser beams that would push them all the way to all the way to Alpha Centauri it reach fifth of the speed of light and get there within 20 years now there's still technological obstacles to overcome focusing the lasers figuring out how these little spacecraft when they get to their destination are going to be able to collect information and beam it back to us but in theory it could work and this isn't the first time that we've thought about sending spacecraft other stars in the 1970s and the British interplanetary society developed the project Daedalus which was a fusion powered starship and there are modern-day equivalents project Icarus project dragonfly it's fine building spacecraft on paper it's completely different thing to build one in real life and that's why we haven't built an interstellar spacecraft yet but in theory we could we already have the Voyager spacecraft venturing into interstellar space there's no reason why aliens couldn't send a probe to us it's possible so it's possible that they could send some kind of invasion fast but I wouldn't worry about that the analogy that or the example that a lot of people bring up is when the Europeans went over to the Americas and the conquest the doors went to the Aztecs and all the trouble that followed a hundred million people died in that European colonization but it wasn't all through violence most of those deaths were caused by diseases being brought over by the Europeans which the Native Americans had no inbuilt defense against now again we don't have to worry really about diseases from aliens because even if they did come here in some kind of biological farm our biology would probably be completely incompatible so we probably wouldn't have to worry about that so I think that's a bad example but I think we do have to be concerned a little bit about provoking contact to early flowers tulips what on earth what kind of trouble could de cars well actually in fifteen sixteenth century Holland they caused a lot of trouble so tulips were imported over to the Low Countries around that time and the Dutch loved them they loved tulips and they started to buy and sell them for ridiculous amounts of money and it created an economic bubble the bubble eventually burst people lost their money lost their homes I called it tulip mania now that was just that the chaos wrought by a simple flower now imagine we make contact with an extraterrestrial civilization and they give us some of their technology it could be far more advanced than any technology we have and maybe we wouldn't even understand how it works but it could do amazing things now technology that we invent causes those problems social media in the internet it's great it's for the interconnectivity we you know people from all around the world are able to connect but social media is changing society you know right in front of ISM we don't know how that's going to change us and it's obviously there are bad things about it and good things unintended consequences of that technology just as simple technology of the internet motorcars that get us from A to B you know the great for the economy but they produce like all kinds of air pollution and that we bulldoze the countryside for roads and car parks an unintended consequence of our own technology now imagine extraterrestrial technology that we're not ready for maybe they give us a replicator like in Star Trek that can allow anything to materialize what would that do to jobs what would that do to economies what would that do to our drive to accomplish anything well could you press a button and have something materialize on the other hand poverty would be eradicated so there's good and bad as with any contact civilization in human history there are good and bad things about it it's very complex but I don't think we're ready yet for that kind of alien technology and so the worry is that by beaming our own messages out and potentially provoking another civilization to reply remember by beaming our message we've given them our language so they can understand us so them we could then understand them when they reply back we may not be ready for that contact and this is what I call the contact paradox name of my book we spent that time looking for life out there but when we find it we're hesitant about making that contact because of the unintended consequences are the misunderstandings misunderstandings that could occur so is the way out of this paradox I think there is now I mentioned that SETI has been looked down on by the scientific community and I think that's wrong because I think large areas of science are about life cosmology you think what was cosmology got to do with life well the history of the universe here why is the universe fine-tuned for life it seems suspiciously set up to to you know to build stars and planets into a allow life to exist why is that so that's something that particle physics theoretical physicists are investigating it boils down to life in the end we study star and planet farming farming regions because we want to understand better how the Sun formed and how planets like Earth formed and how plants like I've got the water that we need for life astrobiologists want to understand the extremes to which life can survive where life could live and what that tells us about her own life evolved so large areas of science are about life so it seems silly to me the scientists are then shun SETI it's just part of the great story that we're finding and so I think before we attempt to contact anyone who may be out there we should do a little reconnaissance first old you know scientists should come together try and figure out as much as they can about life and to look and see if we can find any using spacecraft such as the test mission we'll see if this animation works so tests is the successor to Kepler it's going to be looking for exoplanets around nearby stars next month in December the European Space Agency are launching the key ops mission which is a mission that's going to characterize some of these exoplanets it's going to find out exactly how big they are and coupling that with our understanding of their mass will be able to work out their density and figure out whether they're solid planets or gaseous planets and whether life could possibly exist there next decade the European Space Agency are going to launch another exoplanet characterizing mission called aerial that's going to study the atmospheres of planets like I talked about earlier and look for these bio signatures we've got other telescopes coming online there's the extremely large telescope in Chile that Webb Space Telescope in the future they have plans for missions that are going to directly image exoplanets potentially earth-like planets and we're still going to keep doing SETI and we're still going to keep doing astrobiology and understanding more about life and where life could live and I'm willing to bet that by the end of this century if there is life on a planet 50 to 100 light years away we're going to have found it so once we find it then we can study it we can learn more about it if it's intelligent life is it warlike are they like us what kind of technology do they have what are they like we can eavesdrop on their own leakage and learn more about them and then once we do know more about them then we can think about making contact and opening those hailing frequencies to me that would be the responsible thing to do that would be what I would expect an advanced civilization to do with us and to treat us with kid gloves rather than converting in so just to end with I think the take-home message is that when we do SETI there's a phrase I use in my book the stars are like a mirror we look to the stars for alien life but we see our faces reflected back when we're doing SETI yes of course we're thinking about alien life but we're also thinking about human life we're extracting extrapolating from our own experience and putting ourselves in context learning about ourselves and in writing the book you know I learned so much about human altruism and human intelligence and how earth formed and created habitable environment and how we may go extinct and when we look at advance when we consider advanced alien civilizations who you know as I said we're really they're a proxy for advanced human civilizations and we have a chance to perhaps one day be one of those advanced civilizations but we won't be if we blow ourselves up or we allow the climate emergency to destroy the environment or pandemic wipes us out or a million other threats that we face so could start right now address these concerns and building a better future and perhaps one day we will be one of those advanced civilizations and we will be able to reach out into the galaxy and meet other civilizations but until then we should learn we should listen and just do what we can to build a better future for everyone so that's it thank you for listening [Applause] [Music] [Applause] [Music] [Applause]

Channel: The Royal Institution

Views: 582,371

Rating: 4.6492186 out of 5

Keywords: Ri, Royal Institution, seti, extra-terrestrial, extraterrestrial, keith cooper, contact, fermi paradox, fermi, aliens, intelligent life, lecture, talk, first contact, alien life, drake equation, universe, astronomy

Id: BV_DkQCNfu4

Length: 51min 37sec (3097 seconds)

Published: Thu Jan 16 2020

Reddit Comments

[u/nick9000]

If you are interested in a very detailed look at the Fermi Paradox then I highly recommend this series of videos..