A Little Talk About Aliens: Techno-Signatures and the New Science of Life in the Universe.

one my name is andrew fracknoy i'm the emeritus chair of the astronomy department at foothill college and it's a pleasure for me to welcome all of you to this remotely controlled program in the 21st year of the silicon valley astronomy lectures these program this whole program is co-sponsored by four distinguished organizations the foothill college science technology engineering and math division the seti the search for extraterrestrial intelligence institute the astronomical society of the pacific and the university of california observatories which includes the lick observatory the first uh permanently uh inhabited observatory in the world and all these organizations contribute to the publicity and to finding distinguished lecturers like the one we have tonight i want to remind you that if you are viewing this on youtube we do encourage you to ask questions during the first airing of the program and that email through which you ask questions will flash below it's astronomy at foothill.edu so we encourage you to leave questions if you're viewing a rerun of this later then may 26th of course it's too late to ask questions now let me introduce tonight's speaker um dr adam frank is a leading expert on the final stages in the life of stars like the sun but his current work also focuses on life in the universe his research group at the university of rochester has developed advanced supercomputing tools for studying how stars form and how planets evolve he is also a popular author his most recent book is light of the stars alien worlds and the fate of the earth which won the 2019 phi beta kappa award for science he has written two other popular books the constant fire beyond the religion and science debate and about time cosmology and culture at the twilight of the big bang dr frank is the co-founder of the blog 13.8 on bigthink.com and an on-air commentator for npr's all things considered he's also contributed pieces to the new york times nbc the washington post and other media and amidst all this scientific and popularization work he found time to serve as the science consultant for marvel's film doctor strange frank's work in public outreach was recently honored via the american physical society's 2020 joseph a burton forum award so ladies and gentlemen it's a pleasure for me now to introduce dr adam frank giving us a little talk about aliens techno signatures and the new science of life in the universe dr frank thank you very much uh so it's a real pleasure to be with everyone um let me share my screen so we can get started here and we'll go there and we'll push that button there we go we're getting started so greetings everyone from the uh deck of the rossonate here behind me um my favorite show the expanse you should watch it if you're not watching it but that's not what i'm here to talk about i'm here to talk uh uh giving you a little talk about aliens i want really what i want to do today is uh talk about the um let me start my timer here so i don't go on too long um what i'd like to talk to you about is where we are in thinking about life in the universe particularly thinking about uh intelligent life in the universe um so here's a little uh table of contents it's always good to know where you're going um so we're going to start with is a wii history a little bit about the what i would call the heroic age of seti the search for extraterrestrial intelligence and then we're going to talk about the exoplanet revolution which has really changed everything in thinking about life in the universe and that is going to lead us to thinking about what are called bio signatures um and then that will lead to this new phase in the history of or thinking about intelligent life or exo civilizations as i like to call them uh and then we're gonna spend a little bit more time thinking about techno signatures and what's happening right now with this whole field um and then finally we're going to see how this all relates to us what i call the astrobiology of the anthropocene what does the search for intelligent life in the universe have to do with what's happening to us right now the particular crisis uh the climate crisis that we're in now okay so let's start at the beginning at the beginning of the modern age of thinking about intelligent life in the universe and that starts in 1950 at los alamos national labs when uh four friends four physicists are walking to lunch at the cantina and um uh the the leading light among them is enrico fermi a nobel prize winning physicist who was also just a super genius um and then he had three friends edward teller y kaminosky uh and howard york and they were as they were walking to the um to the to lunch they uh the i uh one of them recently had seen this cartoon in the new yorker which blamed uh um uh the missing trash cans on ufos people had already the the ufo sightings had already begun 1947 was then they began and so that led to a story for you know led to a conversation as will happen with physicists about faster than light travel and aliens and you know civilizations and then they forgot about the conversation when elsewhere to other topics in science and then you know an hour later over lunch fermi suddenly blurts out but where are they right and all the friends laughed because they knew this was fermi this was fermi capturing immediately the essence of the problem and for him the problem here was like well look if there's civilizations forming everywhere across the universe across the galaxy and they can travel even close to the speed of light um then why aren't they here right now so that was kind of the first time this question about alien or alien intelligence is going to be posed by a scientist in a way that's gonna have that's gonna resonate um so then we now uh go eight years uh in the future and we have frank drake the great hero of seti who in 1958 is a young man there he is and he gets hired by the green bank radio national radio observatory um and uh you know he uh convinces his his fellow researchers it's a small team there that hey can we maybe use this giant antenna we have to look for signals um of of other civilizations and so you know uh it doesn't they're they're they're willing and so he does an actual search they they design the detectors they need and they search for um a number for signals from a number of close by solar type stars they don't find anything but it gets lots of attention the press descend on them you know this captures the imagination of uh of the world and it's the first true search for uh um extraterrestrial intelligence other civilizations and then a couple of years later so after this frank drake will say that you know he was kind of like looking over his shoulders wondering who was going to be laughing at him for doing this but in fact actually when he gets a call he gets a call from the national academy of sciences asking him to lead a meeting with the topic interstellar communications and this is a fascinating story of how this meeting came together they pulled together uh uh um drake and the head of the national academy of sciences space division pulled together a list of seven people uh all of whom you know have some interest uh and this uh there's the list uh sagan otto struva and others and the idea of the meeting is you know somehow they're you know they want to talk about the possibilities what's involved if we want to think about you know finding other intelligences how do we break the problem up and the most important result of this comes from frank drake just trying to set the agenda how will we actually organize this meeting how will we organize what we want to talk about and out of that comes the famous drake equation and so let's just run from many of you may have seen this before but let's just run through what the drake equation says what it's about basically what we're interested what drake was interested in is how many civilizations are there out there that you could that we could communicate with that might be sending us messages so that's n the number of civilizations and he broke this up into seven factors each one is going to be a different problem so the first one is the rate of star formation how often stars are forming the next term f sub p is the fraction of those stars that have planets the next uh term is going to be the number of planets if they exist uh that are in the right place for life to form what we call the habitable zone where um the planet is not too hot and not too cold so life could form the next term is the fraction of those planets where life evolves the next term is the fraction of that life that goes on to become intelligent the next term is the fraction of that intelligence that goes on to develop a technological civilization and then finally the last term is the lifetime of those civilizations so what drake did with this equation and it became you know it just it changed the way we think about this problem because what he did was what was brilliant about this is he broke this very hard problem into a seven smaller hard problems some of which you could imagine trying to solve um so for example at the time of the uh when he proposed this equation r sub star which is the rate of star formation people were already getting a handle on that all the rest of the terms nobody knew but at least our substar already they had gotten their hand on so this was a big uh moment in the in in seti in the history of seti also another important moment comes when 1960 when physicist freeman dyson proposes that you know may one thing that advanced civilization might do is try and capture all of the energy from their star to do amazing things and they would do this by you know surrounding their star with a you know a sphere that would have solar collectors on the inside in this way they could harness the entire energy that you know the the cataclysmic energies involved in uh a star um so you know this idea is going to resonate also through the whole history of seti so uh the the idea of dyson spheres is going to be something that is going to find its way you know through studies for the next until now another important uh um milestone in this was the uh development by of what's called the kardashev scale and here is kardashev he was a soviet physicist and he came up with this idea that if you want to detect civilizations you want to what you want to do is you want to think about how they would use energy and so he had these this idea of the kardash kardashev scale for civilizations where there were three different types a type one civilization would use all the power that fell on the planet so you know in some sense you could imagine covering your planet in solar panels right um a type 2 civilization would use all of the power available from the home star in some sense they would they would cover the star or surround the star with a dyson sphere right a type three civilization would use all the power available from all the stars in a galaxy and this kardashev scale this idea echo is going to echo down um uh you know for the rest of of of history and thinking about um uh uh seti so these are the sort of seminal ideas that are being put into place in this classic era of seti that will have you know that will really guide our thinking um another important moment was when fermi's question that he asks actually becomes uh what we now call formally the fermi's fermi's paradox and this actually came from a paper by heart in 1975 and what he realized was that it would if you had even a single civilization that had the capacity to send out probes you know slower than light probes uh or or or or settlement ships colonizing ships that actually um the the time it would take for these ships to hop from one uh star system to another was even if they were traveling at say a tenth of the speed of light was uh very short compared to the age of the galaxy in fact he calculated it and found the time for this colonization wave to spread across the galaxy was about 600 000 years which is way shorter than the billions of years the 10 billion years which is the age of the galaxies so from this he derived a very important for him conclusion so what he figured was since this time is so short the settlement front or the colonization front from anywhere in the galaxy should have spread over the earth by now it should it will have contacted it will have spread over the earth um and so he called he then said he then proposed fact a as he called it which said look there's no settlers here now so what that must mean is there's no settlers anywhere there's no other civilizations other than our own we are alone so this fact a uh became the fermi paradox the paradox part is that well you know there should be civilizations everywhere we don't see any so therefore there we're alone okay now others uh rebutted this there were a number of papers that tried to respond to heart uh including by sagan and collaborators and but there everybody was sort of focusing on this idea that like well this settlement wave this expansion wave of ships hopping from one star system to the other and settling those uh the planets in that star system that you know maybe that front stalls or it stops for some reason so it just it never reached us that's why we don't there's no one here now it's because it never reached us so that was an ongoing debate and we're going to come back to this uh later on um now there was it turns out that as time as people started talking about this there there came to be what was called there was another version of the fermi paradox that people talked about um and this was the idea that there was this great silence so this other fermi paradox remember that the first fermi paradox is why aren't they here now why don't i see any aliens when i walk around uh why aren't they you know why aren't there already you know uh buildings that the aliens live in so that was a like the idea of direct detection we would actually see them indirect detection the idea that you know okay frank drake is looking with a radio telescope and he doesn't see anything um people came to say people came to to think that well we've done seti searches and we haven't found anything so there it therefore is this great silence or um so david brin came up with that term the great silence and it was the the the presupposition was here that we've looked enough uh with our seti searches of distant galax or distant stars and we haven't found anything so therefore there must be a great silence and along with that came the idea of the great filter and the great filter was the idea that well the reason we don't find any other civilizations is because there must be something in the evolution of life that keeps civilizations from either getting to our point or even if they get further that cuts them off so there's some filter evolutionary filter that keeps advanced civilizations from from forming so this has been discussed again and again and again we're also going to look at this at the end you know as we get towards the end of the talk um and so then in the 70s what we get is you know there was frank drake uh and the people who were involved with him they were the first generation the real pioneers of seti but then comes this second generation of you know it's like 10 years later 15 years later and you get people like jill tarter and woody sullivan who was a professor of mine at the university of washington who was a radio astronomer who was also interested in setting he's the one who introduced me to it and then seth shostak and others um and uh you know they were the ones who really you know they they picked up the ball you know with immense courage because the field still you know there was still what we were going to call the giggle factor and what's really amazing you know all of them they were all courageous but we have to really give a shout out to jill tarter because as we've learned over the last 10 years um what women in science have to put up with uh from their male colleagues you know everything from uh you know from sexual harassment to just being you know ignored and here comes jill tarter who is just going to take on the most controversial subject in the field and like a pit bull is going you know jaws are gonna lock on and she's just gonna you know with with intrepid scientific intuition and skills it's just gonna you know go ahead plow ahead would not be stopped so you know we we all owe a debt of gratitude to jill tarter as well as these others um so so uh so you know we're kind of concluding an important piece of the history i just want to give you the background because the ideas that come from this era are going to resonate through with what's happening now um but let's end this uh this little section with um where things stood by sort of the mid-80s or the 70s and the 80s uh and um one of the things people really wanted to do was build like this giant they call it project cyclops they were going to build this immense radio telescope that was going to be sensitive enough and powerful enough to detect to try and detect uh uh signals from distant stars um but you can also ask why was there this emphasis on radio like during this epoch really seti is about radio and there's reasons for that scientific reasons one was sensitivity radio um uh was was going to be particularly sensitive um and also particularly sensitive across across you know from one end of the galaxy to the other optical wavelengths visual light gets obscured by dust in the galaxy so you really can't see from one end of the galaxy to the other radio waves because the they're longer can actually penetrate that or get through those clouds of dust and so um radio was the natural way of thinking um but no matter what uh you know with radio or anything it's going to be a challenging search and particularly because um uh you know at this time nobody knew where to look right so the basic search strategy well you know so the challenge here was you didn't know where to look which stars should you look at okay sound like stars great that still leaves you know a lot of stars you don't know when should you look you know uh you know when are messages emitted how often should i look you know uh what frequency should i look with should i look every hour should i look every day should i look every month um and you really don't know what to look for what kind of signal am i looking for so the bet the best bet that people were sort of pushing for was the idea of beacons that someone was going to send you a purposeful message the idea was that an advanced civilization would want others to know that they existed so they would send a you know a powerful uh uh message beamed um into space that could then be detected and we're gonna see how different that is from uh you know some of the possibilities that are available now but we're really going to end this a little history on a sad note because what happens to seti in 1978 is that uh you know nasa was prepared to do a big project to fund a big project and then senator william proxmeyer uh names the nasa seti project he gives it what he called the golden fleece award which he awarded to projects that he said were a waste of time right and of course this gets a lot we shouldn't give money for defined little green men um and so nasa is literally not allowed to fund seti right if nasa is told you cannot fund seti then in the 1990s nasa tries again to fund some seti pro programs in the early 90s and once again nasa steps in because this is a great thing for congressmen at the time you know to make some headlines you know look like they're being you know budget hawks so for example congressman conte says why should i spend why should we spend millions on seti went for 75 cents i can buy a tabloid and see pictures of aliens that's not a direct quote but it's kind of like the quote and then senator richard bryan cuts all the funding for these projects and says this will hopefully be the end of martian hunting season at the taxpayers expense so nasa gets burned nasa really gets burned and you know uh you know there becomes you know so this is not an official history but you know my sense is that nasa really just doesn't wants to stay away from this because every time they try and get near it you know congress just jumps all over them so this is really the funding for nasa for for seti dries up other than a few uh uh people who are will a few private donors there's just no money for seti anymore that means no graduate students no postdocs the field really goes enters a period of you know great difficulty but nature and science had other plans as we shall see so let's talk about exoplanets so there's this question that has been around for 2500 years and that question is are there any other stars that have planets and you can actually see this question coming up over and over again so for example aristotle and democritus had a big fight about this and you can see them yelling at each other uh where aristotle was like where the you know the earth is the only planet that's the only planet could have life there's no other planet like it anywhere and democritus was like no no no you know uh i believe in atoms and atoms you know uh fill the the universe and they take many different forms so there should be lots of planets with lots of different kinds of life right um and then you know sometime around uh you know i mean the debate goes on during the medieval period around in the mid 1700s uh there's a renewed interest and there begins to be a sense that there should be planets orbiting other stars and so this is the front piece of a famous um dialogue that defontenelle writes uh which shows all these little circles here are actually other stars with other planetary systems right um and then for example so the hunt gets on is astronomy modern astronomy is born telescopes get better people are always hunting for planets and many a career in astronomy was ruined by the claim to find a planet so for example in 18 in their around the 1890s this is uh jay thomas c who was an astronomer um who everybody hated very interesting story nobody liked this guy because he was a jerk but and he claimed to have discovered uh uh exoplanets that he claimed to find uh evidence for planets orbiting other stars he was completely wrong he never admitted and that contributed to his downfall so anyway exoplanets the idea of planets orbiting other stars is an ancient question right and um and the interesting thing was is that uh you know as in the modern era as technology got better particularly driven by the seti folks there was a push at nasa to try and develop the instruments that you would need to be able to detect exoplanets what we're going to call exoplanets planets orbiting other stars so in particular these two meetings and this is the um one of the reports from them in 1978 and 1979 driven in large part by the seti community to you know what do we need to do to develop the technologies what what are those technologies for detecting planets um so this was a huge uh um uh uh you know uh push to you know they knew it was gonna take a lot of time and a lot of effort to figure this out and the reason why the seti community was interested in this is we if we go back to the drake equation the second two terms in the drake equation are about planets f sub p is the fraction of planets or the fraction of stars that have planets n sub e is the number of you know if you have a star that actually has planets n sub e is the average number of planets in the right place for life to form so this is why the seti community was so interested in this so what happens is eventually in 1995 omg we find planets we find 1995-96 is when we find the first planet orbiting a sun-like star um and that the the dam is broke and when you think about it how often in life does a 2500 year old question get answered right but in our lifetime or at least you know those of us who are around then um the question has been answered we now know definitively that there are other planets orbiting other stars and in particular there is the kepler mission which was launched in um you know about 10 uh 15 years ago or so that just um uh you know just really started finding planets wholesale and so now we're at the point where not only do we know lots of planets we also know that there are planets we found planets in their so-called habitable zone planets that might be or the planets are in the right place for life to form and so now actually we've discovered more than 4 000 exoplanets and this is an interesting plot this is a plot of the size of planets relative to the earth and this is their orbital period in days so remember the earth has an orbital period of 365 days so the earth is here this is one earth radius so the earth is uh somewhere right around here and what you see is we have found lots and lots of planets and lots of all your planets of different types we found things like jupiter you know cold large planets we found hot you know planets like jupiter planets that are jupiter size but are like parked right up against their star we have found worlds that we found planets that are uh we don't even have in our own solar system what are called uh super earths um uh we have found lots of rocky planets that's great we found rocky planets that are so close to their star that literally they're molten rock um and uh the the real frontier is actually finding more earth-like planets on earth-like orbits uh but we certainly have found planets in the right place for life to form because the habitable zone the size of the habitable zone depends on the kind of star so for smaller stars the habitable zones are smaller um closer to the star and we definitely found lots of those okay so this was the exoplanet revolution we now know lots and lots and lots about planets orbiting other stars but there were a couple other revolutions that happened that were also going to be important for now where we are in thinking about other planets and life and exo civilizations so one of them was the fact that we have now sent robots to every kind of body in the solar system every planet has been visited every type of asteroid and comet um not all not we haven't visited every asteroid but all the main types that have been already been visited and so this picture here's an interesting picture you look at this picture and that could be the mojave desert or something but it's not it's mars we mars is now a planet that is entirely inhabited by robots okay um and these robots have been trundling around for a while taking pictures and drilling holes and things um and one of the things we've learned from this exploration of mars is that mars was most likely a blue world for a while that it you know mars experienced climate change it used to have a very different climate where there was liquid water on its surface now there's lots of questions about the state of that but we're absolutely sure that there was liquid water rushing around on the surface of mars so by studying our everything in our solar system we've also learned an enormous amount about how planets work and then the other revolution that we need to note is studying the earth or what we call the earth systems and the earth systems are the oceans the hydrosphere the ice the cryosphere the um uh the lithosphere the rock and then the biosphere and we've been able to map out the entire 4.5 billion year history of the earth you know some things we know better than others but we know pretty well about the fundamental changes that the earth has gone through so you know i like this little diagram that shows you these are all the different eras of the earth going from the archaean you know uh uh billions of years ago um all the way up to the holocene where we are now so i always like to show this picture and ask people because this sort of prove you know sort of makes my point about what we've learned from the earth's history uh relevant to studying other planets is here's the question which of these is the earth so i'll give you a minute to think about it and some of you may know the answer is all of them so these are six different uh representations of the different planets that the earth has been through its history so here we have the earth right after it formed and it was literally uh had a molten ocean um this is the earth early on before continents formed so there weren't always continents earth was a a a water world with sort of small islands there's also been times when there's been the earth has been so hot that there's been no ice pretty much anywhere so we've been a jungle world there's been other times when we were almost entirely ice what we call snowball earth phases um and then here's the earth now our happy little planet uh and then unfortunately another billion years or so the um planet the sun is going to heat up to the point where um the oceans will evaporate so be careful about your long-term investments okay all right so we had this exoplanet revolution which now showed us that there are planets everywhere uh we also had the revolution of studying our own solar system and studying the earth what does that do for us what does it do for seti well first of all the drake equation it gives us new data that we didn't have so in particular remember this equation now we know that term 100 we know that term 100 percent we have now where we started off with only knowing one term in the drake equation the exora planet revolution has tripled our uh what we know about uh these terms right so we know that f sub p is one every star in the sky has a family of worlds orbiting it that's incredible tonight when you walk outside look up every one of those stars has a family of worlds they're all places you can stand on them or at least you know a lot of them um you know the the a lot of them are going to have oceans and snow falling and mountaintops and wind blowing okay um we also know what n sub e is it's around one-fifth or so this keeps getting updated but it's around one-fifth which means that basically count up five stars when you look tonight one of them is going to have a planet in the right place for life to form okay so that's huge now what can you do with that well in 2016 uh woody sullivan and i wrote a paper that showed by sort of manipulating the drake equation you could answer one particular kind of question you could ask yourself what is the probability that we're the only time in cosmic history that life and civilizations have formed and so what you learned from the draco this new form of the drake equation is that well you know there's basically 10 to the 22 or 10 billion trillion planets in the universe right so what are the odds that that you know if if each one of those planets constitutes an experiment that nature ran in the evolution of life and the evolution of civilizations what are the odds that none of them ever formed a civilization well that would be 1 over 10 to the minus 22 or 1 in 10 billion trillion so here's how we call this the pessimism line because it turns out if now we don't know what nature actually sets for the odds that we don't know how evolution works on those you know in that way but what we do know from this is that if nature chooses a probability per habitable zone planet of less than 10 to the minus 22 for civilizations to form yep then that's it we're it you've run out of planets nobody else there's no other life existing on the other hand if the probability that nature has set through evolution is greater than 1 in 10 billion trillion and that's not that hard because 1 in 10 billion trillion is a very small number if it's greater than that then you know what we're not the first time it's happened now i can't say whether or not there's anyone else around now but i can say that as long as nature as long as the probability that nature sets is greater than 10 to the minus 22 then there have been other experiments in civilizations and for me what this means is is that you know uh um unless nature is really really biased against life in civilizations because that 10 to the mind that's what that 10 to the minus 22 would mean then uh unless it's really biased against it then this has happened before now that's not that's not a concrete argument that's just an argument by you know by sort of you know playing with numbers but but at least now we have a number to play with right we didn't have that before okay so now we can get to say now we can enter the modern era and ask what does the exoplanet revolution change for seti uh in particular you know in terms of what we're going to do and here's the most important thing we've got all these planets we now know exactly where to look right we know which planets we should be focusing on the ones in the habitable zone the ones that are in the right place for life to form um so we know exactly where to look and now as i'm gonna show you we're starting to learn exactly what we should look for okay so let's begin to think about this so let's talk about biosignatures so a biosignature is what scientists call um what they what they're referring to is the imprint of an exobiosphere in the atmospheric chemicals uh that you can see via spectroscopy so for example in the uh in the earth's atmosphere the only reason there's oxygen in the atmosphere is because of life if all the life disappeared tomorrow it would take some amount of time before the uh the oxygen would all react and combine with other chemicals and there'd be no life in the uh sorry there'd be no oxygen in the atmosphere which means somebody looking from a distance could take a spectra of the light from earth break it up and look at what you know look at the the imprint the other the the finger the chemical fingerprints that are in that light and they'd see um um you know they if they looked at us now they'd say oh there's oxygen in that atmosphere and that could be a biosignature that most likely indepen indicates that there's life there's a biosphere there producing that that um oxygen so biosignatures are the uh the chemical fingerprints of of um compounds molecules etc that can that are produced by life so things like methyl chloride methyl bromide these are all chemicals that life produces that um if you looked at a spectra the spectra is when you take light and pass it through a prism and then uh you know uh do a readout of it any chemicals that are um that are in the medium that is emitting or that the light is passing through are gonna show up they're gonna have a fingerprint what's called an absorption spectra in that light so you're using the light to look for signatures of chemicals uh uh from life in the planet's um atmosphere so that's what's called a biosignature and so you know there's been an enormous amount of work since the exoplanet revolution there's been an enormous amount of work on this and uh over time what people have found is that uh you know the earth's biosignatures change we've mapped this out of how you know during the early earth there's different biosignatures than during the earth uh what the earth would look like now so this is a really thriving business so they're what i could call the rise of biosignature science people have done an enormous amount of work now and it's really sophisticated on what bio signatures we should look for how not to be fooled by you know what we call false positives etc so biosignatures are is now a mature science and all the new telescopes that are going up there's going to be a huge component of what they do which will be looking for biosignatures and that means now we enter the idea of techno signatures right so if nasa's already spending and the nsf et cetera are spending a lot of money searching for biosignatures which would be signatures of what we could call dumb life like microbes it's really microbes that are producing that produce the oxygen in the atmosphere why exclude smart life right remember that nasa sort of got burned by by by congress and so it was like oh i don't really want to do this anymore um and they did some they did some but not the way you know many people would have wanted because they couldn't um so uh uh so but but with the exoplanet revolution nasa jumped all the way in with biosignatures and so you know there was this sense of well what about techno signatures what about signatures of technology so what amazingly happens is and the techno signatures was a name that uh jill tarter gave to the idea that look if you're looking for bio signatures technology will produce signatures as well so amazingly in 2018 congress adds puts language in the budget that says you should search for techno signatures and uh how this happened was lamar smith the congressman from texas who was the head of the congressional science committee who was actually a vehement climate denier uh you know which is strange and if i ever get to talk him i'm going to ask him about that but he was the one you know to his credit it was like yeah you should be studying techno signatures so nasa then holds in 2018 its first meeting on uh techno signatures and this was a momentous event in the field and i was lucky enough uh to be able to go to this and it was like everybody was like kids at a candy store oh my god we're gonna get to talk about it because what nasa was asking for was look if we're going to fund any of this tell us what we should do what are what you know what kind of projects should we be doing and so what came out of that meeting was a rebirth of sort of thinking about life in the universe i mean other people obviously been thinking about it a lot but now there was a sense of the community of like oh my god there could really be some some some some funding to actually do something and so one of the things that came out of this was like for example we started to think systematically about it in a new way um so one of the things that came out of it was uh this idea of techn of figures of merit axes of merit if we're gonna think about techno signatures how should we do it and so this was from sophia chic uh she did a um a paper where she sort of thought about well what are the things we should think about if we're thinking about techno signatures okay well can the search only be done in the future or can it be done now well if it can be done now that's the kind of thing you should do are we looking for techno signatures that are short-lived or long-lived from a civilization yeah of course you want long-lived are we looking for uh things that are had don't have much information or have lots of information so this was the beginning of sort of like okay look we really want to try and put this field on a good firm basis how do we do it and then actually the first grant got funded it was that was a grant that i was the pi on it was part of this team that you can see here of lots of talented people um and we put in a proposal and this was the first techno signature grant that nasa funded um and it funded uh you know for two years it's a two-year multi-institutional study to develop a library of atmospheric techno signatures and it's very exciting um and you know we're now two years into it i'm going to show you some of the results and uh we're now you know looking at a renewal and then some there's been some other grants that have been funded as well so it's a really really exciting moment uh in the field um so let's now talk about what are techno signatures what are some examples of techno signatures well i'm going to talk about a few of them city lights or heat islands that might be you might be able to see on a planet large-scale deployment of solar panels atmospheric pollutants like chlorofluorocarbons and orbiting megastructures uh this picture here this image here comes from a very large grant that we put in jason wright was the pi of this didn't get funded but you know it sort of showed that the community's organizing itself to try and do you know very ambitious things and so we will put this grant in again the next time there's a chance uh and hopefully that one will get funded all right so let's talk about some techno signatures here's one alien megastructures right so this is the idea that um you know you have large structures orbiting a star that you might be able to see as they pass in front of a star so uh the the the term for this is a dyson swarm so it's not a full dyson sphere but it's like a dyson swarm uh um and uh as these things pass in front of the star you would see uh uh the starlight dim a little bit now the amazing thing about this is we actually saw something pretty amazing in what was called uh boy ion star um where this is a this is uh uh uh what are called transits this is the transit data from the kepler telescope of uh uh boy iron star um and you can see that it it's like the light is just dipping up and down in very irregular ways not at all like a planet uh or like a planet passing in front of the star and so for a while people were like totally perplexed by this and you know jason wright and others uh in their paper um suggested like well look one of the things we have to at least consider is maybe these are alien mega structures they had lots of other things to consider like comets but you know uh um eventually we found that uh you know our astronomers found that no uh you know actually um you know it's not alien megastructures uh you know most likely it's dust balls of dust but this just shows you this is the kind of thing you would look for you might find if you had orbiting mega structures the other possibility another techno signature are city lights there are telescopes on the drawing boards right now that could be used to map features on an exoplanet so the next generation of telescopes uh like the extremely large telescope um if say this is this this is a map of the earth right looking with a telescope like this you would be able to recover something of you know be poor resolution but of a map of um of you'd be able to see where the continents were and you might even be able to see either city lights or heat islands with infrared of industrial centers so that's you know that's not terribly far in the future um if there were if you're another techno signature would be if a civilization you know uses large-scale um solar energy collectors then there's light reflected off those collectors and it would show up in the reflectance spectra from that planet people have long known that the earth shows a very clear edge they call it the red edge um in the earth's reflectance spectra because of uh plants and so what um avi loeb uh and uh manozvi lingam showed was that solar panels would impose a sharp edge in the reflectance in the uv so um our group is actually trying to uh do more work with this right now uh something a paper we just our group just produced um uh that jacob hock mizrah and ravi uh um kaparipu uh have led is uh what about you know let's just take let's just start with a chemical that we know about on earth that could only be produced uh by industry and those are chlorofluorocarbons these are the things that have to be banned because they have ozone uh they cause problems for the ozone but what um uh uh jacob and ravi did and their and their other collaborators um is they actually you know ran climate models they ran three-dimensional models of a planet's climate a planet orbiting a small star um and they put you know different levels of chlorofluorocarbons in either one x or ten times you know uh you know the the the level we have now 10 times the level we have now 100 times the level we have now and then they let the climate settle um because chlorofluorocarbons are actually they heat their great greenhouse gas um so they let the climate settle and then they took what we call synthetic spectra they actually looked for what the light the spectra of the if we took a spectra of this planet what would we see in the light and what you see is this is the spectra this is um uh you can think of this as brightness or whatever versus wavelength and right here these um these lines right here these come from the chlorofluorocarbons and you can see that they really stand out right and most importantly what we found is this plot takes a little bit of thinking about it but what we found what we looked for was how much signal signal would we be able to get if we observed um uh a planet um uh uh say you know like proxima b the clear closest planet using um if we had 10 hours 100 hours 300 hours 600 hours 1200 hours of observing time for you know one of the telescopes that are about to go up and what you find is in order for a firm detection you need what they call the signal-to-noise ratio to be greater than five so that's five there and what you find is is that with just a hundred hours of observing time you could get a clear indication a clear detection of chlorofluorocarbons at earth's level um with with these telescopes so this actually turns out to be a huge milestone for uh for techno signatures because what we've shown is that a a civilization like earth that had the same amount of cfcs that earth has would be detectable with earth levels of technology meaning telescopes we have right now so that was that was one of you know that was actually a milestone to be able to show that's true and not only that it would require this would require less time than observing some biosignatures so this was huge i mean at least we consider this to be huge and this paper hasn't been reprieved yet so who knows but you know we feel confident in this conclusion um so you know this is a techno signature which you know with with jwst even the james webb space telescope which is going to be launched next year we you know should be able to if we had enough time if it was there we would be able to detect it now the other thing that happened with this new you know this renaissance of um techno signatures is that we've been able to start thinking about the field again systematically there's there's this new you know group of people young people coming in and starting to ask questions about techno signatures trying to really be systematic to break it down in a way so that you know we kind of can figure out what we should do what are the right directions to go in so there's questions like what's the expected age of a civilization that we will likely detect is there really a fermi paradox how common are techno signatures how what's the lifetime of techno signatures so i don't have much time left but i'm going to try and just take you through this through some of this briefly and i want so i'm not gonna spend a lot of time on it but um uh uh in a discussion with uh the the uh uh astronomer david kipping um uh caleb sharp and i we were asking this question of of you know how well will most civilizations be older than us or younger than us um and particularly the ones we detect will they be older or younger than us and david kipping who is a very good mathematician did some serious math kung fu using what's called bayesian statistics and he was able to show i'm not going to go through this plot because it would take enough time but he did the math and this plot reflects the math and what he was able to show is that you know even if most civilizations are short-lived the ones we're going to detect the ones we are most likely go are going to detect are going to be older than us so that's really interesting because what it means is we're going to have to think about very long-lived civilizations and what kind of techno signatures they're going to produce and that's a real interesting challenge um and so uh so that's one thing that already has come out of this you know the the techno signature studies now another thing that's come out of trying to think systematically about it is uh this possibility the idea of freeing techno signatures from biosignatures and what i mean by that is this um there's a claim that made some people make that techno signatures must be shorter lived than bio signatures you know these these imprints of these uh signatures from technology well they're not going to be around as long as the signatures from biology because of course a technosphere meaning you know the the the um a planet having all this technology around it that should be a shorter lived planetary phase than a biosphere biospheres last billions of years but we don't know how long civilizations last you know looking at ourselves who knows you know maybe you only get a thousand years or so however there was this lovely paper by uh balbi and uh circovic which showed that really gave the really nice argument that look technospheres meaning civilizations are not techno signatures what that means is a single civilization could last for you know 10 000 years but it could produce millions of techno signatures in the sense of like what if it produced uh uh spaceships that would travel you know uh interstellar probes that were traveling from one place to the other um robot probes that such that even after the civilization died these techno signatures would still be out there perhaps still you know sending signals around in their robot ways so there's a you know techno techno signatures and civilizations they go together but they don't have to go together they don't have to be uh uh they don't have to overlap in time forever right a civilization can produce techno signatures that then spread out and continue to live while the civilization dies that was an important realization um uh and along with these lines is thinking about long-term techno signatures uh one of the things we're working on right now is this idea of how do you think about these long-lived civilizations and so what we're drawing into this is something called scenario analysis uh because you could say like oh my god it's impossible how do you possibly think about you know long-term future well you know if you're working in climate studies you have to think about long-term futures because you know you want to know what's going to happen 100 years from now 200 years from now what kind of technologies are we going to have so there's a well-developed study that the ipcc which is you know the people who study climate use called scenario analysis and we're going to apply this to to uh the the evolution of civilizations because what you can imagine is if this is time right you have one possibility that civilization evolves and there's no new laws of physics and really they the civilization can never travel faster than the speed of light like basically the laws of physics we know are the laws that we know now are the actual laws of physics well if that's the case then um uh then the civilization's gonna evolve a certain way if there are no new laws um but you can have warp drives which are a possibility in science fiction um uh you know uh with einstein theory of relativity well how does the civilization evolve in that case so you can sort of lay out these scenarios in a um and so that's something that's possible as well so all right i don't want to spend a whole lot more time on the rest of this people can ask me questions about it um but i want to get uh so i'll sort of sum up now because i don't want to go um on too much longer the one thing i want to leave you with there's one thing i do want to leave you with is the fermi paradox so this is where we'll end right remember i said that there was the indirect fermi paradox fermi paradox where people said look we've done all of these steady searches and we haven't found anything the there's the great silence but as uh jason wright uh in a study that he did based on a study that jill tarter actually did is they looked at all the seti searches that have been done and how much parameter space has actually been explored you know like you know which radio frequencies have we looked at how long have we looked at how what what how often do we look at you know the the there's this giant parameter space that you're going to have to explore the the haystack that you're looking for the needle through and what they found was by looking at the entire history of seti is that if this parameter space where the ocean then the entire amount of water that we've looked at looked for looked through for aliens is a hot tub right so this is like saying you know oh i want to find dolphins and you look into hot tubs worth of water and go no dolphins well that's it there's no dolphins in the ocean so there is no fermi there's this kind of fermi paradox it doesn't exist anybody who tells you that does just doesn't understand what's going on people have this idea that scientists are astronomers every night are looking for uh using telescopes to look for aliens but that's not true there's been no money to look for this it's only recently because of things like the breakthrough initiative which has been uh our breakthrough listen uh which has been so powerful and giving money for to buy telescope time you know now we're starting to actually look but up to now we really haven't looked all right so um i'm gonna end there people can ask me questions about this other stuff if they want um but i'm gonna end with just the idea that there is so much work ahead this is such an exciting time in thinking about uh uh techno signatures and exo civilizations and that you know we're we're just setting sail on this journey and in the next few decades we're gonna have data we're going to have data relevant to the question of life i don't know what the data is going to say but we're finally going to have data which is better than just yelling at each other so i want to end just with an acknowledgement of you know another pioneer we have to point out is carl sagan who is just all over this story carl sagan was amazing and and and how many you know uh parts of this story his his fingerprints are on so i'll end there and thank you thank you so much uh dr frank i think carl sagan would have been proud indeed of your summary of the situation in this lecture and uh i want to say that this is the last talk of the 2020 uh 2021 school year but we will be back in the fall and now we're going to take questions and as i said at the beginning we encourage you to send your questions to the email address astronomy at foothill.edu and it's now my pleasure to introduce dr jeff matthews who is the astronomy professor at foothill college and he is going to be the curator of the question and answer period so jeff matthews i'm going to hand things over to you thank you very much andy and uh thank you uh dr frank for coming out and speaking with us this evening that was a great talk and i would also like to thank all the folks who have been emailing in questions um so i've got a lot that have come in i'm probably going to do a little bit of grouping when people have asked similar questions yeah if i'm going to just break in sorry dr frank would you stop sharing the slides and that way we can see you in larger detail all right good okay great thank you so much thank you so much so um so so there were several people who are off asking questions just about the nature of life right and how that might affect our searches so um so several people ask uh questions related to sort of finding ecosystems so so with one person saying uh life is never a singular example but a system you know so so what is like a minimally functional ecosystem and i think i'll add on to that question you know how can we search for different types of ecosystems well that's really what we're searching for that's what biosignatures are about bio signatures mean you're not searching for like you know a you know a little green man well you know let's forget about civilizations but we're not searching for like a you know a plant what we're searching for are entire planetary ecosystems it's the planetary ecosystem which pumps the the gases the chemicals into the atmosphere and we're using the atmosphere as a life detector so what we're doing is is we are it is the sum total of ecosystems that we're actually looking for you know we can't we're not going to be able to see the plants or the microbes we're going to see the effect of the plants and microbes on the atmospheric composition got it so so not seeing the life directly but it's effects otherwise right okay and so then um there was a question what about things that are really different what about the possibility of intelligent life that's not you know like biological organisms even you know that's maybe like robots or that's um you know even in just some other form that we haven't thought of well that listen i mean that that's a great question and and you know there's a certain way in which you got to begin with what you know and then try and work your way out from there but you know as i always like to say aliens are not magic you know um they're going to obey the laws of physics and you know like one law of physics that nobody's ever going to be able to get around is the second law of thermodynamics which is that you know if you use energy you produce waste right so one of the things to look for you know whether they're robots or you know um you know clouds of nanoparticles if they're using energy they're going to produce you know waste like heat um and so we can you know the way i really like to think about the problem is we should be looking for the overlap the venn diagram between what civilizations can't help but do and the things that we can't help but but detect right so you know any civilization is a system it's a system and what does a civilization do it's a system for you you know harvesting energy and putting it to work that's kind of like almost the definition of a civilization and so if that's what's happening then there are going to be consequences um in terms of things like the second law of thermodynamics uh in in waste heat in chemical you know you know entropy what's called entropy being generated in terms of the different kinds of species uh a chemical species so you know that's what we should look for there's there's no way of getting around certain kinds of uh of of um consequences of being a civilization waste heat is inevitable enough infrared emissions exactly inevitable got it so we got a question uh from curtis regarding the pessimism line so uh i believe that the early universe did not have much in the way of heavy elements so until the first round of supernovas started making heavy elements life as we know it could not have formed does the drake equation take this start time into account that's a great question very well informed question um the thing is is that you know the the the fir which is amazing the first stars form you know the first galaxies in form stars form pretty dang early in the universe so you know it's really you know with it less than a billion years into the universe's history that you're starting to get the first generation of stars which then make the next generation of stars which make the next generation of stars so you know you could try to take that into account that there's not medals until a certain point but it's it's really not going to matter it's not going to change that number you know significantly so but it's a good question okay and so then um transitioning into the questions talking about like search techniques so i'm gonna try to keep these grouped up a little bit here um so somebody asked um i guess this is referring way back to earlier in the talk um when you were mentioning that radio passes through dust so are there any other advantages to a radio search uh besides that the fact that it passes through dust uh you know i'm not a radio astronomer so others you know radio striver might be able to say other you know other other uh again sensitivity also because you can build such giant you know that radio telescopes in general are very not only can you build large telescopes you can build interferometers where you chain together lots of telescopes individual telescopes to get a really huge telescope um so uh you know that is you know so that's another advantage um of radio telescopes as well um so uh yeah so that was that was why it was logical in the beginning to start with radio i mean there's still radio going on and that's what breakthrough listen is about they're doing really great work with radio so you should still keep doing radio as well uh and searching through all the frequencies and everything but now that we have exoplanets that also means that we've got a place to look with optical um uh we can use the the the transmission the light from the star passing through the planet's atmosphere to do this kind of spectroscopy to look for the chemical composition of the atmosphere okay so i'm going to cheat a little bit and throw my own question in here on that so you mentioned the detectability of cfcs with sort of present or very soon technology but you know you just mentioned like the light of the star passing through the atmosphere which is this super thin layer around the planet and so what are the prospects for that detectability people are already doing it there's all there's already it's called atmosphere characterization and we already have characterized the atmospheres of you know um of uh some some jupiters and neptunes so yeah i know it's crazy but it works and you know so i know it it's amazing right that right it's this thin veil but you know it's you you know you get enough time i mean and obviously what you're going to do is you know if you've got a transiting planet transiting mean when the planet passes in front of the star you're going to do it you're going to add that up you know every transit you're going to do it again and again and again and again and again and you know you may have to take you you may need like you know 100 transits to build up enough signal but yeah you can do it and and we already know we already know the atmosphere characterization of some giant planets all right so there are several people asking about um sort of the possibility of techno signatures a bit closer to home so i've got a question from jim asking what does dr frank think about techno signatures on earth for example some of the navy declassified videos yeah that's interesting um you know so i just actually have a op-ed i just wrote for the new york times which hopefully will be in next week um you know so those navy videos are interesting but you know the idea that they're that they're connected to aliens is a huge leap right there there's really nothing about those videos and that data that should that that you know that would lead you to say like oh it's aliens right so so you know what do we have actually from those videos is we've got uh a bunch of pilots talking about what they saw right um and you know the problem is you know if you look at it you know each individual pilot has their own story but somehow in the public's mind these all get lumped together so not every pilot saw the thing doing some you know saw whatever the unidentified object making some kind of crazy turn one of them does but the other you know the other one didn't so but somehow in the public's mind every pilot saw the you know saw the same you know strangely shaped object move in some way that couldn't be possible so that's one thing to remember another thing is that um uh you know these you know uh so so the the first person accounts right eyewitness testimony is notorious for being unreliable right you know it's it's you cannot use first person you know uh um testimony to really prove much of anything and listen if you really want to know what's going on you got to use science and science can't use first-person testimony because what do you got right you got somebody saying well i saw something that would look close well how close can't tell that from what their testimony is i saw something move in a way that i you know that couldn't be possible well how fast was it moving you can't tell that from a first person so then what do you have is you have the videos right now those videos already people have you know have looked at the videos and had you know there's been a number of of skeptics who've like actually taken those cameras and it always seemed to be the same type of camera on the same type of plane and they have um they've shown that this you know that these effects that seemed where the thing seems to be you know moving very fast over the surface are easily reproduced as being uh problems or just you know effects in the optics of the camera right so right there there's a there's a plausible explanation you know a possible plausible explanation for you know for what's being seen and the thing about science i always like to say if you want to know something extraordinary right there's only one way to go and that's science right and so you know the the the level if i were to say that i found a techno signature right let's say i said let's say i claim that i find cfcs on the um on a planet i am going to ex i have to expect the most extreme skepticism from my colleagues as it should be i am going to have to exhaustively like for months and months and months go through every possible way i could be wrong all the possible errors and all the possible alternative explanations before i can ever say and anybody will ever believe me that um that that this is actually a techno signal this is a so with ufos you know it's got to be this if you want to say ufo equals aliens it's got to be the same process and it's just not even close now let me tell you what i think they will be from some of the readings i've done so i've been reading some of the military literature and um uh you know there's a group of military strategists who point out that um even with drones even with simple drones um you could you know what you and in fact you want to do this if you're they call it a pure um peer state enemies a pier state enemy would want to use drones or radar reflecting balloons around these kinds of like these are military maneuvers that are being done why because then the pilots see it the pilots turn at it they turn on their detecting equipment and those drones can then suck up all of the you know they can characterize there's the word characterized the the the electronic emissions that are coming from the plane thereby giving the adversary some understanding of what our um our electron our very advanced electronic detection systems look like in fact the united states even did this in the 1960s we actually put up radar reflecting balloons so that soviet pilots would you know turn to them turn on their radars and we could characterize their radar so that is much more likely and that is i think why the military is like hey man we really got to figure out what this what uh what's going on here so that is just so much more likely than um you know than uh you know this being aliens let me say one last thing about this because this is my favorite thing okay so what we always hear when we talk about ufos is because here's the question what if these are really aliens why don't they just land on the white house lawn and be like yo man what's up we're here and so when you talk to you know people who are really into ufos you often hear well they don't they want to remain hidden right they they don't want us to know because we're not ready to know no but you really hear this is often part of the um you know the way sort of uh uh theory the ufo theory goes but here's my thing if this symbol is if these are these are civilizations that can cross the mind-boggling distances across the stars can't they turn off their high beams right like can't they you know if they and then they want to be you know they want to be hidden they want to be secret well if their mission is to you know to watch us in secret they're doing a terrible job of it right you know why are there lights in the sky why can't they uh remain hidden you know uh from a bunch of hairless monkeys with you know primitive infrared cameras right it just doesn't make sense so that's one of the reasons there's a bunch of reasons why you know i think there's some i think those those that stuff should totally be studied and it should be open and we should do a full scientific study of it it's worth that but the lit the the jump to extraterrestrial civilizations is just not warranted so that's my spiel i hope that's i'm i'm gonna jump in for just a second because i've spent the last week dealing with this issue in the media and i'll just say for people who are interested in following up on the very smart things that you've said about ufos there is an investigator in england whose name is mick west mick and if you google mick west and ufos you will come to a series of videos in which he does that kind of analysis that you were just describing right you can see very clearly what some of these famous pictures that the uh media are so gullible about what they're really about so that's one one way to show the kind of work that you've been talking about mick west is the name sorry jeff go ahead oh no no thanks for jumping in um so uh we got another question in sort of continuing with the close to home theme um what is your thinking about umuah oh that's interesting yeah so omua moa um you know i i think right there's been sort of the debate with avi and i know avi um abi loeb but i think that you know um was really interesting because it showed us what a possible uh you know what what a possible target techno signature might be i don't think there's you know the problem with of course is you know it came through and it left right and so you know and it took us by surprise so we didn't have a whole lot of time to look at it i don't find the arguments for it being a solar sail convincing you know i think it was it's interesting there's lots of unanswered questions but it's certainly not a slam dunk um so uh yeah i don't think oh you know i you know i think again there's more there are easier more plausible explanations for omua moa than it being a techno signature but you know um uh avi was right to raise the question as uh as he did and that's really what's interesting happening now just like jason wright in the paper about uh um uh you know the the kepler the the boy i have a hard time pronouncing it i'm gonna call it tabby's star but it's boy boy alien star um uh that that you know in their paper they pointed out like oh these data you know it could be you know we have to consider it so we know we have to get past the giggle factor where like we consider the possibility like okay one possible explanation is it's a techno signature and then you do all the work that you have to do to show that uh you know that that's the that you know that that there's other there's other easier explanations but you know the idea that that you're going to get laughed at for raising the possibility those days are over okay since since you mentioned boyajian's star um how could we be sure that the aliens are not disguising their megastructure using dust well you can't be sure that you know you can't right um but um but again you know then okay now you're starting to do kind of a science fiction e story that they don't want to be seen it's you know etc but but you're right you can't you know and so then what you have to do is you have to look for other traces other signals you know um if you you know listen if the aliens were clever really clever and they didn't want to be found they wouldn't be found and that's just the way it's going to be um so that that's something that we have to we'll have to deal with um but uh you know we have to hope you know the important thing to understand is also what uh jason wright likes to call the mono uh culture fallacy right just because one culture one civilization wants to do that doesn't mean everybody will so you know perhaps there are some civilizations that are really determined to not be found but you know um if they're if you know if there are more than one civilization perhaps the others don't so that's just we have to hope for in this search okay so i think we've got enough time for a couple more questions um yeah and so um we have somebody asking about um with the with the ice moons being ice moon oceans being discovered in our own solar system are there any particular bio signatures for worlds like that sadly probably not you know which is which is really interesting right we have found i keep talking about the habitable zone right this zone where uh the temperatures are right for life to form but actually you know the the you know europa this this ice covered yeah this ice covered moon with a with a deep deep ocean underneath it uh orbiting jupiter is outside the traditional habitable zone so that just like you know that adds a whole new layer of complexity to it and you know if if some if there were if there was life underneath those ice we would not be able to find it from a distance and so you know now you have to hope that perhaps if they you know if it becomes intelligent in you know and build civilizations that they would eventually come out of the ice and there might you know and they might build you know things in space and such but you know for for bio signatures and techno signatures for for things that really are under that 10 miles of ice i just don't see how you'd ever be able to find them from a distance bummer yeah all right um so so here we go into our final question for the evening um and so the question is uh what do you think of the great filter and i think me i'm gonna tack on to that i'm gonna take you back on that you know is that helpful to us thinking about that is that helpful to us here on earth in any way well um the interesting thing about the great filter one thing is that it's tied to the to the to the fermi paradox that version of the fermi paradox which i said doesn't exist so right now we have no reason to think there is such a thing called a great filter because we haven't really looked for civilizations long enough to say that they don't exist so you know so the great filter is still an interesting idea but there's no reason to think there is one okay but the great filter is actually interesting for thinking for of our own what's happening to us now and unfortunately i didn't have time to sort of go into my spiel about the astrobiology of the anthropocene but humanity is clearly uh in the middle of an existential crisis that could easily um uh mean the end of civilization it doesn't necessarily mean the end of human beings because that would ask a lot but this you know global networked high-tech energy-intensive civilization is definitely up for grabs with so with uh climate change um and i've done a lot of work that was what my last book the light of the stars was about i was looking at um the degree to which uh an anthropocene a era of climate change may be common for any civilization that that you know emerges and evolves and one of the things we found in our studies is that yes it probably will be you know when you start to harvest enough energy you have a climate impact so um in that sense you know uh uh the climate change and the or the anthropocene may be a kind of great filter that we are right now in our adolescence uh um you know as a species uh and you know adolescence is a dangerous transition but it's a natural transition and so you know hopefully we'll make it through but it's perhaps not all civilizations do well thank you so much we end with the issue of whether there's intelligent life on earth let's hope the answer to that is yes but dr frank thank you for a fascinating evening we really appreciate your being with us everyone if you are happy to have talks like this we encourage you to subscribe the very same page you're on at youtube allows you to subscribe and then you'll be notified of future lectures as we put them on again we're going to take a little break over the summer we'll resume probably toward the beginning of october with more silicon valley astronomy lectures thank you everyone you

Channel: SVAstronomyLectures

Views: 30,661

Rating: 4.6370654 out of 5

Keywords: astronomy, science, astrophysics, science news, space science, SETI, technosignatures, Drake Equation, Fermi Paradox, Great Silence, life elsewhere, exoplanets, astrobiology, biosignatures, life in the universe, Adam Frank

Id: 9NyZ2GY9968

Length: 79min 26sec (4766 seconds)

Published: Thu May 27 2021