Life Beyond Earth: When and How Will it be Found?

00:00:05 foreign director of the center welcome to this program

00:00:40 can you hear me now still not can you hear me okay I met narcissian director of the center Welcome to our program today which was proposed and organized by Professor Chris simpi Professor Chris simpi is a university distinguished professor of astronomy at the University of Arizona he has over 220 ref referee Publications on observational cosmology

00:01:12 galaxies and quasars and he research his research has been supported by 20 million dollars in NASA and NSF grants he has won 11 teaching Awards and has taught three online classes with over 350 000 enrolled in five million minutes of video lectures watched Chris MP is a past vice president of the American Astronomical Society and he has won its Career Education price he's also been NSF distinguished teaching scholar

00:01:44 Carnegie councils Arizona professor of the year and the Howard Hughes Medical Institute Professor he's written 90 popular articles in cosmology astrobiology and education two textbooks a novel called Shadow world and nine popular science books The Living Cosmos How It Ends talking about life how it began dreams of other words humble before the void beyond the future of space travel

00:02:15 Einstein's monsters The Life and Times of black holes and an upcoming book on exoplanets Worlds Without End he was the first person who participated at our first round table at the Helix in 2012 and it was about the beginning and so now he's here again Chris yes warning

00:02:48 um so uh I'm delighted to be here and to add for organizing these I I got from him the eye-watering number of 200 around that he's of these that he's done if you can imagine that an all manner of topics all interesting um so I'm delighted to have been able to invite and then come this illustrious group here we're going to do a little polling but let me introduce them and these are this is a very truncated introduction just doesn't take too long

00:03:19 these are very illustrious people with a lot more information you can read online maybe their Wikipedia articles even if we trust Wikipedia anymore um so um starting here Lisa kalzenegger is a founding director of the Carl Sagan Institute to search for life in the cosmos at Cornell and and anything named after Carl Sagan is just like you know inestimably high in the esteem of any astronomer um she's been named a young innovator by Smithsonian and Time Magazine she's won

00:03:51 many International honors uh I'm a little jealous she's got an asteroid named after her I'm I'm I'm trying to angle for that I don't know quite what the inside track on getting an asteroid is but I'm um I'd like some tips and and if you get time with her you can ask her about what it what it might be like to surf on water worlds um I'll hop around Dave Kipping is uh director of the cool worlds Lab at Columbia University and it's a generally

00:04:22 cool guy of course he's pioneered the search for EXO moons and I hope we get to talk about that and found the first two candidates and that's the pretty much the bleeding edge of looking at exoplanets and there are smaller progeny he's also an expert on techno signatures another topic I hope we get to looking for spectral signatures of technology and not just microbial life on exoplanets and his research ethos apparently is no idea is too crazy so

00:04:54 we'll hold you to that Rebecca Oppenheimer is a professor of astrophysics and curator at the American Museum of Natural History just up the road she holds three patents I'm a little jealous of that too and uh it's fine uh yeah exactly yes and co-discovered the first brown dwarf and her Optics lab is is really pushing the envelope for characterizing exoplanets with the abilities to detect planets smaller than

00:05:25 the Earth orbiting uh cool Stars so that's we've got bleeding edge technology Theory and observation here in the room um Sarah Seeger is a professor of physics planetary science Aeronautics and astronautics don't you want to add a couple to that chemistry one day I hope you don't have the teaching load of four departments or three departments okay at MIT she's a member of the National Academy of Science a MacArthur fellow and has many International Awards including being an officer of the Order of Canada

00:05:58 which is their highest civilian honor and I just imagine it has some incredible regalia that goes with that but it happened during the pandemic so we didn't get it so I want to see picture online of that ceremony um she's Deputy science director for the NASA test mission which is you know successor to Kepler as the sort of Cutting Edge exoplanet search mission um and and we'll talk about it I think but but anytime you can ask her about why star shades are really important

00:06:31 um so these are our people and we're going to do a little uh experiential learning here it's low Tech the people online have a Google form people in the room we're going to do the low-tech style you know because when the apocalypse happens and we lose all our apps in the internet I still want to be able to teach and do things so we'll use paper so we're just going to ask three simple questions just to set the scene to where you're thinking about this subject is um so this is like origami 101 you just have to figure out what to do with this but basically fold it in half

00:07:03 and fold it in half again and then a panel is exempt from this of course because they're biased sample um and then based on the question you know you just pulled up pointing forward your answer to each question the online people are using a Google form so we get the data um so we'll start with the first one about the existence of any form life of any kind beyond Earth just what do you think about that is it A B C or D this

00:07:34 will give you a minute to organize your folds and then when you're ready just don't want to see but over there yeah so we'll just see what you think okay it's that's a lot of a a lot of a a little bit of the other three okay [Music] um so we'll go to the next question which is very similar

00:08:04 but can we scroll and then who has control those slides it's a good question yeah I don't have control of the slides your life in the uh no that that would that's a very good suggestion but it would take our entire time so we'll we'll loop back to that we won't ignore it um so the second question is really only

00:08:35 different in one word it's the issue of intelligent life beyonder or something we might be interested in same question same method and now it's a little more equivocal there's probably yes so this is an interesting difference we'll see what the online numbers are because I think they're more online than in the room so it's a less certain here some probabilities and and then the last question is uh

00:09:06 if I found Earth is found for the first time what will it be quite interesting these are not all mutually exclusive as you can imagine so quite interesting front page news for a little while profound for astronomy and biology or scientific event of this yeah oh okay all of the above we got one all

00:09:36 of the above so that's that's pretty emphatic majority opinion that it's the scientific discovery of the century and I agree that's fine you're not astrobiologist but you're obviously I think this subject is important and if it does happen you know Nobel Prize will be awarded someone in this room maybe not me I'm a cosmologist I wouldn't know an exoplanet unless it bit me in the ass pardon my French and not any of you I think but um

00:10:07 so we're here to talk about the state of the search for life in the universe which is it an interesting phase so I'll just start just a quick go around and you don't have to be held to what you say particularly because we'll unpack it all at leisure um if you were going to just Hazard a guess of a time frame and a method by which the first life beyond Earth will be found what would you say Lisa I would say catching the lights of the planet with the telescope like the James Webb Space Telescope is

00:10:38 our first ever opportunity to do so so if life's everywhere can be we have a shot if it's not we need to build a bigger telescope but I'm quite hopeful but I'm very positive on this that we get the first whiff of something really interesting within the next five to ten years because we have to add up the data okay Rebecca I guess I would say um on a similar time scale 10 20 years oh you you doubled it actually yeah okay

00:11:08 but that's fine that's right that's insane I mean it matters personally I suppose but um my sense is that this might happen in a more dramatic and unpredictable way than we can know at the moment and in fact it may be within our own solar system and perhaps we'll come back to that but okay good yes we will Dave um I think the question just to

00:11:38 speculate like this is something I'm going to push back a little bit because because I think to be honest none of us really know and uh when I'm talking to the public you know I'm putting on my scientist hat and it's one thing to talk to my friend or you know over a couple of beers and speculate wildly about life in the universe but if I'm talking as a representative of the community then as a scientist I have to say I have no evidence as to whether there's life out there sorry to me on that voting card I want to see I don't know that that should be for me the answer we give and

00:12:11 I don't want to assume whether it's jwst or whether it's techno signatures or something else because I don't want to close my mind to what might end up being because as Rebecca said it could be a total surprise the way we just set it so and if we set it at all so I'm just I try to remain very agnostic about this question and which paths will lead to the right answer okay absolutely since I'm last I will agree with everybody I definitely think we're going to find something but we're not going to know what it is or it's going to be very hard to be sure of it so if I had one single

00:12:43 vote I would put it on our solar system and I would put that to sample return it's kind of a new buzzword NASA wants to bring rocks back from Mars we want to bring parts of Venus clouds back even people talk about even more complicated destinations but like to test something in our laboratory with tools we have that are incredibly sensitive is probably our best bet for a definitive detection but whether life is there or not of course is not up to us right okay well let's go with that because we're going to have plenty of time for exoplanets but two of you

00:13:14 mentioned the solar system fine it's our backyard um Mars is slightly habitable maybe um and there are other places so let's drill into that a little more I'm many people in the audience probably remember the um the fervor over the Allen Hills meteorite and the press conference with Bill Clinton and then the sort of disappointment that's set in slowly and some people just right but let's not forget it could definitively be shown to be incorrect whereas when we think about an exoplanet think about the sky at

00:13:45 night and the Stars you can see they're just points of light and so it's much harder to say one way or the other so that's why I'm voting for sample return right so I I actually like the idea I've always imagined it'd be wonderful if we put um something on Europa and so that is these icy moons in the outer solar system melt down into the ocean if you turn on the camera and there's a fish looking back at you and then you can you know get Elon Musk who have some billion dollar Sushi and you know go out there and forget that so that would be definitive

00:14:17 if you saw fish or even you know whatever something swimming around I don't think anyone would have you know a question of course they would say it was fabricated in Hollywood but you know and there is breakthrough Enceladus I haven't followed the news on that it got about 100 million dollars from Yuri Milner I suppose and uh you know no no not that much there was a study you know if one could do it for 100 million then this billionaire would consider sending a mission to fly through the plumes like there's like a

00:14:48 geyser and to like see if there was any sign of a byproduct of life or anything but it you can't do it for 100 million that sounds like a lot but everything in space think about it like costs 100 times more than on the ground at least for now it was an intelligence in Europa they're kind of a different Beast almost to thinking about Venus and and Mars as well the challenge with detecting life if we did to Pet Life on Mars or Venus would be is it truly an independent origin of life or was that some panospermia contamination back and forth between the earth your broken cells it's

00:15:19 harder to imagine that happening because it's protective thick oh I see lid and so I would be much more excited about the discovery of life in Europe because to me that would be more compelling that there was a second independent origin and thus I'd feel better about the chances of life elsewhere so is that uh asterisk always going to hang over anything we bring back from Mars I think maybe Sarah might be a person I mean I think my feeling is you'd have to do some kind of genetic sampling or something to try and establish an independent origin but what that in

00:15:49 practice would look like is something you have to ask the biologists I think one of the other thing to bring on to this is like for Mars specifically right we have this Warrior they might we we might have just brought hitchhikers along with us on the earlier missions that could survive so it doesn't even have to be panspermia right and then when you think about spermia where you could bring life from one place to the other everything else being equal if we assume that we need water for life and a surface then the Earth actually provides the longest and best condition so I know

00:16:21 that it sounds much much better people want to think they're from Mars right maybe the life Came From Mars or from somewhere else but just by we don't know how life started or we know that we have life right and we know that we had water for a long time here and there's chances are that if we find similar in life somewhere else it probably came from our planet so they were like earthlings that happened to live on Mars if it's the same origin is more likely than everybody being immersling because water just wasn't around that long on Mars but

00:16:51 how however that may be and if we find Life on Mars and Venus in Enceladus are you Robert if it has the exact same chemistry in the DNA pairs right so we're going back to bio we will wonder we will always wonder if there was a contamination in the best possible sense that life spread so what we really want what we really really want the scientists to find is something that has just a different chemistry in the DNA pair just one I don't care right

00:17:22 something that is just different and then as David was saying then you know there's a second origin of life and if there's a second within our solar system and it's few planets and moons right then the chances are just so much higher that it could have evolved somewhere else too and this is why even finding like a bacteria somewhere that looks different that might not be the life that we all envision communicating with or so that's what that gives us the the

00:17:52 chance that this should have happened somewhere else too if it happened twice in our own solar system so so let me with Sarah um you know we can talk about how much more information you get by bringing the perseverance Rover is stashing rocks right now to bring back 20 30-ish uh and then when on Earth they can be analyzed molecule by molecule I'm not a geochemist but that's obviously a lot of information compared to a noisy

00:18:23 exoplanet Spectrum so what might we what level of information would we get from a Mars Rock of known provenance as opposed to the meteorites that well I mean it depends what's there it's what Lisa's saying if we could find a really complicated molecule like so complicated that it's extremely unlikely it could just be made in nature like our DNA molecule I think everyone agrees there's no way that could be made but a different type of DNA not our own if we could see that we'd be like wow that's just awesome so I think that's kind of are the best

00:18:54 well to stream that we find there is life we look at the molecules there's something so complicated that it's just nothing you would normally find lying around to the most frustrating situation will be if Martian life did truly start independently of us and it just converged to us genetic solution okay so I've done my team has like found all these obscure paper they're not obscure to the people who work on them but so you know our DNA we you know the latter it's the so-called base pairs acgt and some person out in San Diego

00:19:25 figured out how to change a couple of those base pairs like a different type of Base it doesn't even hydrogen bond it bonds a different way suck it into a bacteria then that period bacteria survives and replicases and reproduces with like this different DNA with these different this different rung and now of course they started up a company to try to like they have a startup that's supposedly going to make new drugs you know because it's like a different type of bacteria so like the fact like that it would converge like the identical DNA is just I think not a

00:19:56 biologist but from this one example I gave you that it was if someone could do it in 10 or 20 years presumably nature would have way more use your time and so we don't need to it to be the same right so so it is compelling to bring the material back from Mars like I'm not saying I necessarily want to do that I'm just saying that like having been a part of this I'll just maybe like give a brief explanation as I can I'll give you two separate things so this idea of finding a gas in the atmosphere that doesn't belong it turns out we can take credit right for past astronomers

00:20:27 astronomer James jeans nearly 100 years ago wrote it in a footnote that oxygen here on Earth it's so reactive it shouldn't be here it's only here because it's produced by life and that maybe we should look for oxygen elsewhere so this idea that we should look for a gas that doesn't belong supposedly it's been around for over nearly 100 years I was part of a team I was just perfectly involved with the big Discovery where we found a gas that isn't made by life it shouldn't exist it's called phosphine in the planet Venus when we got burned so badly by the community tiny signal maybe people who

00:21:01 people looked at the data didn't recover the signal other people recovered it wanted to attribute to a different gas there's like this huge story that I couldn't unpack for you you just have to dial back 20 years and in different totally different ground-based astronomer you are all you two at least were here Mike mama he found methane on Mars with the ground-based telescopes methane could be made by life it could be made by geology but the pushback was so severe and even now I just found out that there's been a Rover that's detected it and supposedly an Orbiter uh it's still not believed so

00:21:34 this idea of like gases that don't belong I'm also trying to be provocative so someone will disagree but you know it's very um contentious the flip side of the gases that don't belong is is David Lovelock you know Gaia telling the telling NASA in the 70s you're wasting your time you know Mars is dead you know it's I mean that was a blanket statement not enough information but let me jump in What Sarah was saying so I think what you get from us right now is also the this is 20 years of experience that we

00:22:04 had I'm repping for you right now so if you have a rock and that rock has super complicated molecules and you have it in the lab and you can get it to 10 different Labs on Earth people will agree that doesn't to me necessarily mean and I completely get reserves coming from right because phosphane and methane and so on but I think what what we are allowed and that's by chance because there's so many stars out there that happen to have Planet at the right

00:22:34 distance that might or might not be like the Earth right but those ones we cannot get to because if you have our own solar system and you shrink it to the size of a cookie then the next star over in the same scale is about two football fields away so we can't get there we cannot get a sample we can but we have numbers that are forever in our favor we have thousands of these stars and it turns out that every Star has at least a planet could be like Jupiter or

00:23:06 Saturn like you're big or small but every fifth one has one that's small enough to be Rock like the Earth and at the right distance so not too hot and not too cold so what we lose in terms of we can touch this and everybody will agree to this cannot be made otherwise right this is a different base pair of DNA and so on we gain in numbers because if we have this combination not on Earth and love blocking 65 of one of

00:23:37 the first people who who uh who made the argument of the pairs of gases that would react together that would be oxygen and methane that usually go to CO2 and water thus if you find oxygen and methane at the same time and they haven't gone to CO2 and water yet some things producing this in big amounts right now or they would have reacted that's basically the argument and then you have to trace back do you have any way to get these gases that require no

00:24:09 biology right that's the first thing you want to do can you get this without any biology involved in this specific combination of gases and there are some caveats we can talk about but basically this specific combination of gases we can't get in a normal temperate Planet without life at least not that we know it right we have no solution other than at least the oxygen is created with life but you need the other gas there to make sure that it would have reacted to CO2

00:24:39 and water so that there's really a lot that oxygen makes right now so dialing this all back there's going to be a fight in the scientific Community about whether or not the specifics are right but I think that's being an optimist again if we were to find the combination that we cannot explain with everything else but life that indicates life on our own planet that I think for at least half of the

00:25:09 scientific Community would be the Smoking Gun so there will always be voices against that right so I think the thing to do is have the panel discussion when we have that exciting date in hand and have people right exactly I can disagree here actually I have this I have a sidebar question but go ahead Rebecca but I have my sidebar question is your crew right or have you got your dibs in on rocks from perseverance yeah we have some Mars rocks so yeah over across the street across the park um and we also have some of the Stardust

00:25:40 Comet dust over there when you assume that you know what you're going to find you're making a huge mistake and I this is my biggest theme of my career has been look for things that with the least uh restrictions on what you're going to find when we discovered the this brown dwarf back in 1995 it had very clear signatures of methane

00:26:12 water carbon monoxide carbon dioxide it turns out a little bit of ammonia as well an immediate reaction of the theorist was this data is fabricated it's all wrong this can't be true because my models don't show this to happen there was one theorist in Japan who did predict it and then suddenly everybody decided oh hang on this is a natural thing um so and the way we found that was not by biasing our survey to look for strange

00:26:44 things orbiting nearby Stars it was to open the parameter space as much as possible whatever is there um all we had to show was that it was orbiting that star and that would tell you how big it was and how what its temperature what so I I find these arguments that we have to find this combination of molecules not very convincing to me scientifically that's because I I mean it gets back to this whole question of a second origin of life that we have no evidence that

00:27:15 that didn't happen here on Earth in fact there could be pockets of life here on Earth that have not interacted with us um one could they don't necessarily have to be on the surface there's plenty of life that's not on the surface this is the shadow biosphere yeah this kind of thing oh there's there's one there's the other one there's a silurian hypothesis that there was a technological civilization that we can't see yeah it's a Doctor Who episode who couldn't like that one thing I'm a little bit uncomfortable about with looking for

00:27:46 gases that don't belong or pairs of molecules like this you can extend this right so you can say you're looking for anything which doesn't belong and that's kind of what tetna signatures do we look for things which we think planets by themselves shouldn't be doing what stars by themselves shouldn't be doing and you can extend that you can look for things in the solar system that shouldn't be long artifacts or you can look in the sky and see something in the sky that doesn't look like it belongs and think that's an alien flying through and so the danger is whenever you see something that that you don't recognize in your current understanding you leap to life

00:28:17 and you leap to aliens every time it's a god of the gaps type uh way of deducing life and it's not very satisfying if that's your if that's your means of claiming aliens and we have to be cognizant of the fact that our understanding of biology chemistry physics solar system is finite and is ever evolving and growing and so it's very challenging how do you look for something which but you know is outside of known laws when your knowledge of those known laws is itself incomplete that's always going to be a challenge if

00:28:48 that's your definition for looking for life well I'm going to follow up a little because um you know when it comes to an unknown metabolism what we we know Gil Levin you know swore for decades that there was the indeterminate result from Viking was impossibly a positive on a you know something that we weren't looking for so just because you've mentioned it and we do talk about it techno signature when you're talking about can you just elaborate on how we think of those and what does that mean I mean attention to is very Broad in in traditionally when

00:29:21 we sort of seti the search of extra intelligence it was pretty much radio focused it was looking for radio Transmissions maybe a prime number sequence or something and that would be fantastic because then the ambiguity be very low I think that's always been the great appeal of techno signatures is that if you if you get something like that like a message with Rich information encoded and compressed there'd be very little doubt it was artificial um and as as time has gone on we we've realized that we are using radio less and less for communication so we shouldn't just limit ourselves to radio

00:29:52 and so techno signatures has now broadened out to include really anything could be climate change on the planet it could be the heat island effect that we have in New York City that you could thermally map from afar um it could be the satellites were pinning up like starlink that you could maybe detect the glint off so any any sign about technology um and then the problem there is that you're now making speculations about alien technology which is again where you get into this very slippery problem and of course we had this with omo mua we had this with boyajin star two very

00:30:23 weird astrophysical effects that were detected and again it's God of the gaps as soon as you see something you don't understand there's always going to be an astronomer that that will come in and say well it could be an alien because an alien can explain anything absolutely anything he's a very smart astronomer so he writes a book yeah well there you go so that is another problem there can Sarah can you analogously you know for our audience to Define biosignatures and you know the problems or we Loosely call a biocentric gas it's a gas that is

00:30:54 made by life that accumulates in an atmosphere of a planet far away and one that we can detect remotely with our space telescopes that's a very straightforward forward definition but it turns out to be incredibly hard to actually find one and unpack that and we're not quite there yet reflect and Spectra would you include that it's true the red Edge or something because you've written you wrote a paper where you opened up the universe of possible chemicals and right well my team had worked

00:31:27 every single molecule that's in gas form like at some kind of plausible range of temperature some pressures and we found so many gases like 14 000. and the large number of those gases believe it or not they have like a halogens they have like a fluorine or something that's very light attached to it and we wanted to know if how many of these are made by life like are they all made by life I would challenge anyone here who's not a chemist to think of a gas and the Chance is it's actually made my life it turns out that every molecule in our atmosphere that is

00:31:59 there to the part per trillion level tiny tiny amounts is actually made by life although it usually has a dominant Source that's not life like even ozone is produced inside some cells so what if you found a a couple of neon lines on a planet but I forgot to say one thing though I know I forgot that whole story about Wednesday signature because our inert gases don't really do anything life doesn't use them yeah that would be awesome okay but so

00:32:30 the idea is that they're just so many gases like the mold in your fridge I think everyone has that that smells bad that's a biocentric acid the Pine Forest we were in Central Park today it was so beautiful the flowers are coming out on the trees those are bio signatures but most of them just aren't in produced in high quantities right you're walking around you're not like overpowered by like lilacs everywhere only when you walk by that one tree so there's an analogy of this with minerals you know as the Earth evolved geochemically that number of mineral species Grew From dozens to hundreds and thousands are

00:33:02 implicated with Biology so if you're doing reflective spectroscopy and Counting mineral species in some yeah think about these gases by the way it ended up being a bit of a wild goose chase because molecules if you think about a water molecule it's an oxygen and two hydrogens the atoms have round like those of us who have to teach it I'm sure Lisa can do this better than I can it's the cheerleading molecule so it could go like this it can go like this you know the atoms if I'm oxygen and my hands are hydrogen it has a lot of ways to move around so it turns out all these 14 000

00:33:34 molecules if they have like an end point you know that would be like water it would show similar features to water in the Spectrum I'm oversimplifying that but the point is that molecules have similar what we call functional groups and they may appear the same to an astronomer so it's kind of um we actually found other useful thing it sort of hit what Rebecca's saying that if you set out to do one thing you might find something else completely unexpected and that project kind of went in a different direction you don't know what you're looking for but just to all of our credit because we share a similar thing of

00:34:05 being around like at the beginning as Lisa too but um you know we always set out to like make a framework so all this hard work we're doing we think we're predicting and understanding but in the end we're just making a framework so we find the thing we don't understand we can fit it in because even though the people didn't believe you you got good reason to believe it because you know Jupiter is methane and you know you knew that's what we did you know yeah I remember yeah a really interesting point which is this the evolution of the chemistry of Earth you know sent over the past four and a half billion years it's gotten much much

00:34:36 more complicated with time but what happens for another 5 billion years before the sudden you know before it seems unlikely life would exist here although I always imagine it'd be fun if the Earth got ejected from the solar system we'd probably carry on I I don't think we need the Sun but carry on we saw this channel no I'm not kidding for New York in New York

00:35:06 the thing is yes we could all die we could wipe out our human survive yeah you know like when you were a kid too I mean we have a lot of Technology now we don't need the Sun but life doesn't matter [Laughter] so let me just loop back a bit to just momentarily to Venus because they've mentioned it first bracketing it with Mars and so we have you know methane on Mars and phosphate on Venus as being

00:35:36 these low concentration tantalizing biomarkers but you you you bracketed Venus and Mars so you're still a little you're holding the door open for well just just because the panspermia situation so I'd still want to see maybe yeah we could get in the bar tree bring it back and really slice and dice it and see what was really going on maybe maybe they're not going to be convinced but I think just detecting life on either of those too is insufficient at least to establish that how there's life elsewhere beyond the universe and by the

00:36:07 way when we talk about life yeah the question was life beyond Earth I mean a lot of cosmologists would say the universe is infinite so if universe is infinite then of course there's there's life elsewhere it's just Infinite Space for that to happen I think we're really interesting is life in a vicinity to us that we can observe it and have scientific evidence for it and so it's kind of a moot point to worry about life on either side of the universe because it just of course can't interact with us so I think when we're talking about life we are interested in the nearby stars that wst will be

00:36:37 targeting the solar system and maybe even our own Galaxy because obviously if there was a roaming civilization our galaxy that would seem to have some potential implications to us go ahead so just to jump back and what we were saying and so what we have and I completely completely agree like with Rebecca and everyone that as scientists we're looking for everything right but we had discussed the problem that we're having to uh to to come back to the

00:37:08 thing is like is this really a a form of life right and so now when we throw in life as we don't know it completely don't know it right and we cannot make it in the lab that's our biggest problem if we could make it in lab we could change things right we could figure out how life changes what the gases is the change for example that goes into the atmosphere we could figure out how some of the geochemistry is going so of course we're looking for anything that we cannot explain too right so we're not limiting ourselves at all but it is a really uh I think also a valid question

00:37:39 for somebody to say so uh you want to go and look for everything what we do what I do but so what's he going to tell you right and so there is a subset and especially because Rebecca just brought up and you brought up before how our planet evolved through time that's the first paper I've ever written actually about how our planet evolvings through time would look like seen from a telescope and it was much harder than I ever anticipated and luckily I didn't know how hard it would be because I don't think I would have ever written that

00:38:09 paper it was like took me three years to get the model together because we understand so little about our Earth the further we go back in time and so I think one thing and then more than happy to jump to actual Finance I think one thing that we have to um base our search in is the one planet we know that has life ours and there it is critical that we actually look at the whole thing through through time

00:38:39 and also at the incredible diversity of biota we have so yes most likely it's not going to be a planet like the Earth right now with green plants right there would you would have like all these things that would have to get exactly right right and if you're trying to look for humans then you probably would need something like an asteroid impact and the dinosaur is dying out or you might have dinosaurs who send signals you know who knows but even if you return the evolution of our own Planet the argument

00:39:10 is in the biological community you wouldn't end up with us because something else would have been just a little bit different evolved life absolutely but probably just not us right or just the conditions outside a little bit different no asteroid impact not us something else so I think our planet provides us with a wide range of life that actually lives here if you go to Yellowstone for example you see all these beautiful colors that are different kinds of life and so in a way

00:39:41 we did and in my team is we just took this and then I call it bag borer and steel we basically talked to every biologist we could find we happen to have something in the lab that was colorful that they did something else we were like so don't you want to send this to us you know we're gonna measure it and see how it would look to my telescope because you could imagine let's go to an ocean planet so there would be like more oceans watches let's go to a planet with an ocean and you would have an algae bloom red algae that covers the whole ocean

00:40:12 that'd be something that for a planet close by as David was saying absolutely like you want something close by so we get enough light to identify if there's life on it that's something that you'd be able to see in a reflection Spectra not now but with the next generation of telescopes as for example Sarah has figured out how to help us do that get enough light and so this is just the one thing before we jump off that I wanted to move in that we have an incredibly diverse set of life especially when you

00:40:42 look through time on our own planet and to me it would be foolish not to use it to its fullest extent if we look for Life somewhere else and then of course life could be very different and we look for anything that's out of the ordinary that we can't explain but I love your I will borrow your phrase now David it's the god of the gaps or what do you call it beautiful goddess of gaps because everyone was like aliens but it's so easy right if we don't understand something in science it's great if you you can call it aliens because then it's

00:41:14 done you know it's just like it's just aliens that's just a core truth of astrobiology we have to learn as much as we can from the history of our planet as much as we know it and if we don't and what's the role of contingency and so on so I want to do leave do you want to leave the solar system behind get out of our backyard but one more question uh of the objects mentioned and talked about in some lying of Mars Venus Enceladus Europa nobody mentioned Titan yeah we're missing Life as we don't know

00:41:45 it so what what should we how should we think about Titan we've got dragonfly we've got some interesting ways to approach Titan but I think it's really fascinating and it's it's a very cold world so the chemistry is quite different from what we know here it's only 93 Kelvin which is way below zero Fahrenheit Celsius um I think it's a very compelling place to go and look for things and as you mentioned we're sending some helicopters there we should send a code quadcopter

00:42:16 okay it's technically technically way easier than Mars because the atmosphere is thicker than there yeah exactly the same yeah I think the pressure the atmospheric pressure on the surface is about a bar right it's the same as here in this room so you could fly things easily but you could also put a submarine in the methane Lakes what were you finding there I mean if it would even survive but I think that's really really cool place to go look for anything weird I mean it may not be

00:42:46 biology but there's some very strange stuff going on on that world so in your parsing of possibilities where the what is Titan Titan's awesome it's a bit harder to get to it's so cold there might not be as much variety of chemistry that could happen but I think it's amazing the problem is there's too many planets two and moons too little money yeah and we're and when we talk about these the sort of cryogenic bias for this outer solar system moons and so on uh you know referencing back to how far how hard it is to detect an accident why didn't you

00:43:18 tell us why EXO moons are so hard to do for people who think well you've got thousands of exoplanets how hard could an exome moon be well I mean I've spent like my entire career trying to do that um I guess I guess it's hard because if it depends on how big the Moon gets um and it turns out you know we were optimistic when we started the search we thought moons could be as big as you know Earth or even larger than that super Earth and of course we built this mission called Kepler which detected thousands of transiting plants plants passing in front of their star and it

00:43:49 found plants as small as the Earth quite often um and so that immediately tells you that it could find earth-sized moons and we didn't I mean we looked really hard for those things so my feeling is that earth-sized moons are pretty rare if they're out there um however we know in our own solar system that moons have formed in at least three major different ways it like impacts circumstellar discs around Jupiter and uh Saturn and you have captures like Triton around Neptune so there seems to be at least several ways of making big-ish moons and so I would

00:44:19 eat my hat if those types of moons don't exist out there and I guess what's so exciting is that wst is finally giving us that capability to detect those moons I do think it's interesting because um uh there's an interesting psychology thing that I've learned about looking for moons that is relevant to this dialogue about life and experiment is biased that we've talked about this human element and you know I've been one of the few people looking for Moons for a long time and I've always known personally if I claim an EXO Moon it would be really good for my career right

00:44:50 because you know we all have a sense of ego and we all know that science rewards success it doesn't reward no results but I've been just publishing no results for years on this um and so you whenever you see that hint you know many times I've looked at a Transit and seen that that Moonlight dip I was looking for and it turned out to be a false positive I I always have to control my assignment the most because I know I have the most in it I'm I'm the most biased person looking at this data set there could possibly be because I have a personal

00:45:24 um weight riding on it and so I think about that a lot in the search for life that we all want the answer to be yes I think well most of us want the answer to be yes and so it does every time you look at that little spectral signature that looks like life it's so easy to get over excited and jump into it and that's something I've learned from the Moon story and I think it could be relevant yeah I've had an not with life but I've hadn't that experience more than once where you're like wow I found the most amazing thing and then you might do whatever you can to the data that amazing thing is there until you go back

00:45:54 to the telescope take new data nothing I want to know if that happened to you oh all the time oh yeah sometimes it's like you have to be very careful I mean you know like like David was just saying you find something that's truly remarkable or some extreme thing like the brightest star ever seen or the largest galaxy or I don't know you have to be very very careful with how you evaluate that because your initial calculations may tell you something nuts but responsible scientist has to confirm and

00:46:26 confirm and confirm like with the round dwarf stuff we waited well over a year to publish that because we needed to confirm it well that's a it's such a good example because the the field is littered as with the First exoplanets with the bodies of people's reputations yeah but people are like oh you publish this garbage but they usually get it in nature or science you know one of those Publications I don't publish there anymore one of my favorite stories in this just to just to add this in is is Percival LOL with

00:46:59 Martian canals yeah because you read his uh books which I studied quite extensively uh when I was learning about him and he was convinced there was life in the universe everywhere that was just his opinion and he was convinced further that Mars must have life on it because he saw the ice caps he was like there's water there there's water there's like he was just he was he was a slam dunk in his mind there was life there he just didn't have any evidence and then he went and looked at you know through his telescope at that thing and he was told by an ophthalmologist in Boston that he had the greatest eyesight he'd ever seen

00:47:30 and so he was pre-loaded to a think that everything he saw was real and B that aliens are everywhere and so as soon as he saw a mirage these streaks across Mars he immediately interpreted it to be Martian canals and he finished you know one of the best telescopes in the world at Mars's closest approach for 30 or 40 years so yeah does anyone know how the story goes like when he found out it wasn't it was just a of his right it was just the well he he never never popular books on it I'm

00:48:00 grateful in a sense to him because his Knight assistant was a Douglas who you know said no that's wrong it's not there he got fired and he went down the road he founded Stewart Observatory that's why I have a job so yeah but um okay let's let's let's pivot or move out to the the exoplanet regime and and maybe we should start because it's in the news all the time and people have such expectations uh and I don't want you to pour cold water on those great

00:48:30 expectations but James Webb what can and can't James Webb do in this field in the next years anyone all of you I'm sure can tell me this I think just Lisa's really the expert I was I was reading her papers to learn about this subject so I've really enjoyed her stuff on this I owe you a coffee okay for the first time gets us to the edge of technical possibility to look at the atmosphere

00:49:01 off a planet that is about the size of the Earth but it has to orbit a star that's much smaller like a small red star is it going to be easy no because stars have their own characteristics so the biggest problem we're facing is that we have to take the effect of a changing star out of a very small signal because if you have a planet like the

00:49:31 Earth uh think of the atmosphere so David was saying when the like when the planet goes in front of the Star right it blocks some of the light from the Star this is how we find the planets but while that's happening part of the light from the Star gets filtered through the atmosphere of the planet before it hits my telescope and Sarah made this amazing I actually am not half as good as doing the cheerleading thing about when light hits a molecule it makes it swing and rotate thus part of the light actually doesn't get to my telescope producing

00:50:03 basically a passport stamp of what molecule the light hit on its path to me so that's the story but now the problem is this atmosphere if it's a giant planet is quite extended lots of gas so lots of gas that the light can actually filter through now if you go to an earth then the atmosphere is basically like the peel of an apple and so that's what you have where the light can actually go through so your signal is Tiny so the James Webb Space Telescope for

00:50:34 the first time allows us enough light capturing capability so that we can figure out if there are differences in this peel off the apple right so the light that's let's say green that goes through hits the molecule doesn't come through because the molecule swings and rotate the light that's a little bit less green goes through because it doesn't have the right energy to make the molecule rotate and swing that's how we read an atmosphere but now on top of this the

00:51:05 star will change that's my background and the signal is so small that I actually cannot do it in one pass so if I collect the light of the planet going around the star right that's should be it but it's just not enough so I have to wait until the planet comes by again and add that light and I have to make the assumption that the star didn't change much and then the planet didn't change much for the opponents probably

00:51:36 true because you see the whole thing so if it's winter here and some are here and then some are here in winter here probably the same but the star could have changed just because it's so much brighter just tiny changes of the stars and red dwarfs are fairly active very active and so I'm just paraphrasing this because we have the first time the opportunity to actually do this Earth's size planets at the right distance in this habitable sound around this small red stars have we encountered issues yes

00:52:09 are we working on them yes and this is the Royal we because there's a lot of amazing young scientists who actually get this to work so I'm now one of the older gear who says good luck I I this this is going the right direction I see the third question how is will it work will it work I mean I think some people are convinced it will but if it if we can't solve this problem of the background star changing we're not doing this at all and in fact it's not even just transit to Transit it's in a single Transit there's spectral features from the star that

00:52:40 overwhelm the planet because you know star spots people just think they're cooler Stars they're not right their Spectra is very different sorry we sound very serious here but it's like it could be a showstopper for us and then also James Webb was you know designed it was it was specked before exoplanets were really weird things it's probably not optimized for this experiment instrumentally however I would say and I completely agree sir you know we finding what the showstoppers could be but that is exactly like what Rebecca said before right you find something that you didn't know existed like a brown dwarf or some

00:53:11 chemistry in an atmosphere off a star right that you just never had the capability to see because your instruments weren't good enough now our instruments are good enough and to me what's our Saving Grace in a way because this is at the edge of technology is that the launch of James Webb was so perfectly executed that instead of getting five years that's a nominal timeline we think we get 15 extra and those 15 extra because we have enough fuel on the James Webb allows us to

00:53:44 learn from this data that we now in addition get from the Star what do we need to learn about the star what do we need to learn to get the signal right we were basically all a little bit panicking and this is now me interpreting this for everyone else so like if we have five years and we need three or four years to get the signal right right we don't have much wiggle room if anything is different than we expect and we know it will be different because our instrument got better and so that's why I'm hopeful and we've written a lot of our a couple of what we could

00:54:15 do with the James Webb Space telescopes theoretically of course but now Sarah is part of the James Webb Space Telescope team I am I don't know I think you guys are not on it again but yeah I don't accept my proposals it's too radical but basically scientists can ask for time of the James Webb but what I just mean is like so Sarah and me happen to be on two different instrument teams and when you make an instrument and when you put so much time into deciding how to make the instrument they give you some guaranteed

00:54:46 time up front to make up for all the time you spent writing this and making the instrument and thus we've seen the data that I'm not allowed to tell you anything about but we've seen the data and the data is exquisite and there are problems but we are addressing them it's not as if we're like oh my God there's no way in hell we can figure this out it's kind of like okay we expected there to be more that we didn't know yet and a lot of amazing young scientists and all the scientists but mostly young scientists are actually

00:55:18 figuring out how we get around it and so um with the extended lifetime of James Webb I'm actually very hopeful that if there's life where it could be anywhere it can be and if it changes the atmosphere in a way that we cannot explain other than with life we have a really 15 years though it's a long it's a long way well and if you're talking about 15 years so we put a lot of our tips on James Webb but there are three large telescopes under construction they're all going to take first light in

00:55:48 the next five to seven years we think um with 10 20 25 times more collecting area than James Webb if the Adaptive Optics however on the ground yeah so so what should we expect from these large new ground-based telescopes and will can they do things that James Webb cannot do well I mean this is something I've spent 30 years working on it I think you got the idea from me earlier that if you want to detect life you need to do it definitively by seeing the fish right or whatever

00:56:18 um that's a theme of I have seen that movie it's not working out well oh that Europa talk about fish um with the exoplanets that has been my directions directly seeing them that that to me you can learn so much more about them than with these indirect methods which is that the way the majority of them have been found either through the motion of the star due to the mutual gravitational attraction of

00:56:50 the two um or by it passing in front as you know you guys have done a lot of work on that um I recently got into one of these indirect areas and we had a conference in Santa Barbara last week and I decided I'm getting out of this because it's just too complicated I want to see the damn thing I want to see you know see it move around when are the first slight instruments that can do that on the any of these three large telescopes yes yes so are they first light or are they second lighting yeah

00:57:22 they're planning chronographs on these things so chronographs are basically instruments and I developed a lot of the technology that's being used in new major missions and the large telescopes now um the ideas you block out the light of the star so that you can see something paint next to it very trivial way to think of it is you know at night there's a car you're standing on the side of the road the car is coming toward you with these bright headlights on you hold up your hand and you can see a lot more around that otherwise the light is blinding you

00:57:53 so we've developed a lot of different very precise ways of doing this with Starlight in astronomical Optics and I the reason it has interested me so much is that you see the thing you're not you're not um you know assuming that there's something there that's doing this that is a planet you actually see it and once you see it then you can dissect its light into the Spectra and find funky molecules and

00:58:24 whatnot it's a much more convincing way I think in in terms of even though I I'm not saying RVs or transits are are crap I'm saying um if you want to convince a large number of people when you see it it's there I mean right and I guess the problem from the ground is as opposed to space is you you're looking through all this Gunk that happens yeah include water and oxygen which is exactly what you're looking for so it's just a romantic image just saying right about the pale blue dot and yeah

00:58:56 to be the first photo yeah yeah it would be spectacular to see that so we have image uh quite a number of planets and and what what you call a planet becomes sort of a question in and of itself it's kind of like a uh one of the people here have said earlier um the whole question of what is life is is very philosophical you can ask the same thing about planets and stars you know physically what are the differences here what are we talking about and

00:59:27 they're kind of blurry lines you know nature doesn't have fine luck there are no there's no such thing as a straight line in nature who let alone a demarcation um so we should expect just to you know punctuate it for people who don't know the three large telescopes under construction or we have the John Magellan telescope in Chile 22 and a half meter the Caltech California telescope is 30 meters a little stalled out on Mauna Kea but maybe they'll get built there and the Europeans have a larger the largest

00:59:59 of the three most advanced of the three funded by European treaties so that money rolls in like the tides as opposed to the entrepreneurials are winning an American system which sometimes doesn't work so these telescopes will be doing these experiments in the same this time frame we're talking about and it's going to be very exciting but maybe let's go back to it I think it's going to be amazing to do this from the ground because we can actually fix it and the telescopes are going to be there not just for a five or luckily now probably a 20-year time scale but

01:00:31 the big problem Rebecca just brought up is if you want to find life and gases that characterizes an earth analog like our planet now you're starting to have the problem not just that the atmosphere between you and the Stars moves and blurs your image that you can take out to a certain extent but the problem is like the water concentration in our own atmosphere the oxygen concentration in our own atmosphere we do not know down to the level that we would see a tiny

01:01:03 signal from another planet right so the only way we can do this and we there's a lot of amazing people working on this is to say look the other planet moves around its start so there is a differential it it moves compared to us and when something moves this is also why we know that the universe is expanding then the lines that indicate that like energy hit light hit a water molecule for example or an oxygen molecules those

01:01:35 lines shift still the same barcode so we know this is water but it's not exactly where we find it in the lab it's a little bit redder If It Moves away from us or a little bit Bluer If It Moves towards us so what you need to do is you need to find the small Earth analog Planet at the biggest change of speed compared to us to shift those line as far as possible away from the lines we have in our own air and this is where

01:02:06 even with the 40 meter telescope it will be at the limit of possibility because that now limits how long you can observe right because the line smear if this thing moves and it also limits um when you can observe when you can observe this planet because if the lines of just overlapping then there's no way you can tell them apart and so anything that's not an earth analog is going to be amazing with these telescope from the

01:02:36 ground but anything that's an erst analog will be extremely extremely hard because you're just looking for the stuff that you that that your light passes through in our atmosphere as well and so just to paraphrase I think we can do a lot from the ground but for earth analogs like real analog planets like the Earth we might have to go to space because it becomes so complicated to tell the difference between our

01:03:07 oxygen and any potential of the oxygen and just some subtext here we're talking about these different methods there's also different solar systems and I think we've danced around this a little bit in this discussion so we're talking about these methods like transits or this method of like looking for the spectral lines this is probably only going to work for small stars from jwst it's only going to work for the smaller stats red dwarf stars very very common and you have earthlight or we think Earth-like plants pretty close to them but are they truly earth like we don't know and then you have sun-like stars like our own sun and those of

01:03:38 course they have to be further away to be in the habitable zone and they're really only direct Imaging is the only game in town for really having any attempt at getting the buyer signatures in our sort of near-term lifetime because jwst this star's just too big you would never be able to detect these buyer signatures in the transets and I think that's important because we live around a sunlight star so we know sun-like stars have life around them we do not know about these red dwarf stars they are the most common type of star in the universe they live far longer than

01:04:09 the Sun and from the early statistics we have from transit surveys they appear to have more rocky-sized plants and hydro Zone around them than some like stars do so there's three things that like look great about them but then it is such a different environment they they flare a lot we've already talked about their activity and so we have many legitimate concerns about whether these red dwarf stars could truly be habitable and we might not get an answer to the sunlight stars for for a little

01:04:40 bit longer yeah this is uh the experiments are hard so I think we're also alluding to for for people not in the field the fact that even with by far the largest telescope we've ever put in space approaching the by far the largest telescopes on the ground these are hard experiments and the target selection becomes important and so I want to go back to Sarah on the fact that you know everyone knows the success of Kepler most of those are hundreds of light years away and it could tell us why test

01:05:12 is such an important part of this picture in terms of feeding us the best targets for the next wave of experiments well test is designed to just look at so-called nearby stars but there's still tens hundreds of light years away it's think of like just four glorified telephoto lenses bolted to a platform staring at a giant strip of the sky for a month and then tiling each hemisphere of the night sky in a year so that's what Tess is doing you know it's not really friendly in every like maybe half of the web or less planets are from tests okay and I mean I think

01:05:44 there's so many we could just I mean once we get going it would be I think too tedious though we could go through like every method and all the different options but there's so many of them but I think maybe can I just add something on to what David was saying it was a really really good point right this is a completely different environment and what we found with Kepler what we found with tests is Sarah was just pointing out and you were pointing out Chris you know uh it's just easier to find planets that are the right temperature around small stars because they have to be closer it's like a bonfire a big bonfire

01:06:16 it's warm you stand further away small bonfire Closer by but that means the clothes should buy for a planet is that it comes around more often so in all of our methods except for direct Imaging we actually find them easier and then by chance nature seemed to make more of those Rocky worlds around the small Stars so good for us because these are the ones we can find by chance but the point I wanted to jump on and what David was saying is really great right so now you have a different environment

01:06:47 that doesn't mean that it can be life but it might mean we'll never find it because it has to be subsurface to actually shelter itself from radiation or maybe the atmosphere is not as permanent you know or it has to be forever in an ocean right because water also mitigates radiation it's not a problem you just have to be further down and why don't we know and this brings us back to the solar system if there's life on Europa and Enceladus because it's subsurfaced we'll have to go there and

01:07:18 drill a hole in the ice to see if there's a fish hopefully not but if there's some life hopefully in those oceans and if you put that star 10 light years away from me and I can get to it anymore I can't do that so there will be a subset when we haven't talked about and so it's great that David brought this up of planets that will be habitable that will have a striving biosphere that will not be accessible to remote observations and this is why when we're

01:07:50 selecting our targets we're trying to learn as much as we can from the diversity of life on the earth to hopefully make a first good guess about which ones are good targets and then there's necessity if we can only look at small planets around small Stars right and we have no other option then it's definitely worth looking because we cannot as we said before discarded to say like ooh you and me I I usually when I teach this I say you and me landing on

01:08:22 the planet really bad idea because we're not used to radiation we'll die but life that developed there may be subsurface or in an ocean could have completely different mitigation strategies for Harsh radiation because it would have had to evolve for it we didn't so there's the subset of where life can be actually visible and change the biosphere but you and me wouldn't survive cockroaches would going back to Sarah's point about New York uh but

01:08:52 cockroaches here what are you talking about okay there's no cockroaches here I'm sorry but then there's also this really interesting subset of life that we'll be striving out there but we won't see it because it's not remotely detectable and you just have to accept that so the the field is obviously heavily driven by technical capabilities instrumentation and so on and and James Webb as remarkable is is one of the it's a general purpose telescope that's Hubble Is and you know and the exoplanet

01:09:22 Niche has fitted into these and some cosmologists like our esteemed discussion leader might want to use it for something else than finding life for the Universe I don't know Sarah was a cosmologist and she just jumped she jumped ships yes she saw the way the wind was blowing cosmology was kind of a dead end field you know so but tell us why we need another yet another generation of you know purpose but we've been talking about these red dwarf stars but if we want to find and have options of like planets orbiting

01:09:54 sun-like stars true or twins we have to get above the blurring effects of its atmosphere and go to space do the chronograph or we have the external version called starshade people have always known about this it's like me saying I want to do sample return you know that's because we think it's the easiest way to get a job done not because it's the best way and we might all agree that's what the red dwarf stars are it's the easiest thing we can do it's not the right way we really want to do it and so these more this next generation of capabilities that one in particular that you're involved in what does it do

01:10:25 that James Webb cannot well and will not do it's going to block out the Starlight so we can see the planet directly just like what Rebecca's talking about but from space instead of the ground and it's challenging technically incredibly hard it's one of the hardest like we can barely do it under the laws of physics that we have you think about like how small an atom is or various other physical factors we're just lucky we're going to be able to get the job done but people have thought about this for decades it's just only recently become technically feasible and so challenging we're still another one or two decades out

01:10:55 what's really interesting is that the design of this telescope is very sensitive to how how close is the nearest Earth-like planet with life on it that's maybe you want to survey say a hundred and you hope that one out of 100 have life on it but then the question is how what fraction of stars have those earth-like planets around them and that's the number that that Kepler was designed to answer that would inform the engineering requirements for this this telescope that we're talking about now and frustratingly it didn't quite get

01:11:27 all the way there because it turned out stars were more tricky than than we thought and then there was a little engineering failure on board at three and a half years with the Gyros so there's some reaction Wheels know that I'm just looking at an instrument Builder but they knew there was a problem with the reaction Wheels before Kepler launched apparently they opened it all up and looked at it but but you can't just go and buy one like go to the store and get a replacement I feel like in New York I don't know I've just been here for the weekends but everything's available like whatever you want there's 24 hour store you just go and get it

01:11:58 this one reaction says you can't buy used books anymore in New York Strand Strand Bookstore really amazing still you see so think about this you're going to launch the super expensive thing you know you have a problem are you gonna wait three more years to get a new part like no to sort of cross their fingers there were four they only needed three but you know one failed then another failed yeah but people got really clever without it but the point one of the points was that nature didn't cooperate so people would joke like our sun is not a sun-like star

01:12:28 which is silly because it's like the icon right but all the other stars were so variable so we need to double the amount of time but the telescope didn't last double the amount of time they always do like what Lisa was saying about Webb how it launched so perfectly now it gets 15 extra years almost every thing we've put in space lasts like way longer than it's supposed to except for Kepler that's kind of like if you buy a new washing machine it's got a warranty and it feels like one day after that warranty expires that's just exactly what happened yeah I said I just wanted anyway so the point was we don't know

01:12:59 the number how common are we have a big uncertainty on the number yeah it's like not knowing at all I mean the uncertainty is so big it's like not knowing yeah so it doesn't matter we can just come in there's one thing that's been alluded to indirectly I mean we you know we have the archetype this and recognizing that the Red Dwarf opportunity is is a is a good one because it's what we can do and then the archetype of the Earth-like planet around the sun-like star but I've heard or I understand that you know super Earths are may be super habitable and

01:13:29 maybe the Earth is not the best of all possible worlds a leibniz quote or whatever so um well I'd take issue with that actually and it's based on some work that this guy did over here I think we're on a super Earth but if you look at the physics of rocky planets there's an inflection point at about twice the size of the Earth where things start to look more like Neptune for example yeah yeah it's like less than two or 1.6 to 1.9 yes so it's a good

01:14:00 number we're on a super this is about as big as they get so if you're looking for a place like this they're not they may be much smaller actually um so I that I that super Earth idea you know maybe we are on a planet that is outrageously inhabited with light right there's also a fun statistical argument that probably cosmologists would appreciate as well that if you uh you know a random Soul born into a random country you're most likely to be born in a country with a high population rather than a small population mediocrity

01:14:31 principle right and so if you're born into a random Planet you'll most likely to be born on a planet that has close to the maximum capacity of population rather than one of the smallest capacities so there's been some clever Bayesian arguments made not by me but my I think Fergus Simpson wrote this paper showing that you can you can predict at the upper size limit just from that one data point is about one and a half Earth radii for the maximum size which turned out to be what we basically found observationally so we may indeed be on one of the largest Rocky plants for life but I think we can also go back to and I

01:15:03 agree where you come from Chris right it's like astronomers are incredibly good at naming stuff right so you have a string that's bigger than the earth you wanted to find an earth you want to get it published and you want people to be excited about it it's like oh we'll call it supers right we call things a black hole like oh it's dark right oh it's super doesn't mean it's better at all it's just that astronomers have learned how to name things to not be told by every journal in the world but every

01:15:33 journalist is like why would you care right naming is half of the convention of getting a foot in the door to tell you why it's so interesting that we found these things so you know super is under quotes Ultra Cool is one of the best so so just momentarily back to the the place where this subject will hit the popular imagination and Consciousness when results being our start to get published um sort of I'm not timed on expectations but just just remind everyone why

01:16:06 there's no well we've already sort of pretty much covered why there's no smoking gun biomarkers but why the the claim is that the person bold enough to claim they've detected exobiology why that's going to be such a hard thing to do with any particular set of data is that because it's true right I mean it's because pretty much every single gas can be made another way other than life that's why so where do you say when you're doing the experiment I've only found one gas uh that exists in our

01:16:38 atmosphere that's not made okay by life actually so where do you set the bar for yourself and the experiment if you're Imagining the experiment well the bar is gone unfortunately okay in this case so I would I would make a little bit of a connotation of what Sarah just said the question is like if you're a scientist right if you want to be a hundred percent 100 sure of anything let's do the Big Bang because your cosmologists right we're not 100 sure of the Big Bang we're 99 something percent sure right and so I

01:17:09 think in science I do the same for the biosignature right have I found something that I cannot explain with anything else than life then to me that's step one that's incredibly exciting then I'll as a scientist will throw everything I have at it to try to dismantle it we I have data now that geologists and chemists and other people can use to figure out if they find another explanation for this right if it still holds up it now reached the second level so we with everything we know

01:17:41 right now it's a caveat right we could learn something different tomorrow have no other explanation in life and I think this is never the point is you're never going to have that there's never going to be no other explanation right but there will be um you can think or I think about it in a way that is there any other option yes but is that option going to be likely if you like Model A Thousand planets and and that's that's all I'm just saying is that on Venus let's assume the phosphine is real for a moment I know that's

01:18:12 incredibly controversial we've just gone through that like live and people aren't willing to do probability they're like okay if you get phosphine coming out of volcanoes the volcano has to be more explosive then remember that one volcano that messed up all the air travel more explosive than that you have to have tons of water in your mantel you can model the likelihood of that I mean people they're not willing to go there and so these are exoplanets we have no information on so you're never going to get past a level that's the problem but you can do all your models or you can say I have this

01:18:42 probability but the bottom line is that I'm just telling you what not me now the rest I'm sounding very aggressive but just kind of passing on the rest of the community that's just today what what about the analogous question there never being no other explanation for a techno signature for nitrous oxide chlorophyll carbons whatever you want I don't know there are other explanations there may be some that are hard to have false pluses for like a prime number sequence or something I think is pretty different but even then it could be a hoax uh you know so even then there's still a false positive

01:19:13 um the big you know the big the fundamental problem we have is and we've taught us a few times now but we are trying to detect something where we just don't really understand all the physics and so we don't we call this like the false probability right chemistry right and we don't know we don't know the false probability rate from of chemistry or physics to produce these uh spurious signals that could trick us and so that's where a lot of the work is actually happening right now is trying to quantify these positive rates more and more but I think we all have to be braced for the fact that there will be a claim of life and we've had it many

01:19:43 times in the past before and when that claim is made it is just the start of the Journey of Decades of work of and maybe we'll never maybe the the confirmation is will always be just 99 and never 100 like xeno's arrow in agency never exactly going to get there but we'll be able to converge to some high confidence optimistically assuming we can figure out these difficult problems right and I also think like David just made this beautiful

01:20:16 cannot explain other than with life yes I won't be able to say definitely no other things but this is now we have a start and a journey we're going to learn much more and we're going to figure out what it takes for life on other planets and this is where we're not at yet and I think that's actually the level this is the this is the result I want to get to I want to be part of this exciting real start of the journey where we're not having a bottle of wine and arguing whether there could be life in the universe but where we have to our best

01:20:47 guests right now no other explanation convincing explanation as than this being like and skepticism is such a high quality for any scientist so it's going to be there's going to be a lot of skepticism and as it should be dry that's what we need right yeah so you want to answer this question we just have to go there I wonder if I can jump in I want to ask a question that was brought up at the very beginning by someone about defining life first so where no one's tried to do that and it's interesting because there's like you've

01:21:19 talked about everything around it how you might find it um and of course one of the topics that came up over and over again is something to do with the complexity or some pattern that you might discover that suggests that life caused it because nothing else might explain it well I'll help a bit because since we're all astronomers we get to sweep that definition of like the end of the rug what we say like what is life but what is my thoughts yeah it doesn't mean we haven't thought about it but what does life do life metabolizes and life uses

01:21:49 chemistry to extract energy from the environment to store energy right we just kind of go and it creates certain sorts of patterns it leaves some sort of we're hoping some sort of footprint of that metabolism but it won't necessarily and so that that's a problem that you we could look at uh trappist-1a one of the one of the top targets for years and years and we weren't set to anybody signatures hypothetically but that doesn't mean there's no life there right underneath the surface yeah there could be life like on Earth that eeks out as this a meager existence and some life

01:22:19 only divides itself it sells once every year and that won't show a signature when I was actually trying to drive that is if you find if we well look we can't say anything about things we can't find yet I mean we're looking for things we can find right first of all of course it could be things difficult that we know about right exactly but I'm wondering if something really puzzling arises and there is some sort of phenomenon it's very complex and suggests something that makes many of us think it could be life isn't that also useful to investigate you say well I don't know if it's live

01:22:50 but wow we're gonna have to come up with some interesting models to explain why there's oddly enough on Venus in the atmosphere there are these anomalies there's a tiny amount of oxygen at parts for Milling level there's tens of detection of ammonia there's a massive depletion in the cloud layer of sulfur dioxide and water vapor and this list kind of keeps going and people knew about all this stuff four decades ago and they're just like they couldn't handle it so they shelved it went on the shelf for 40 decades until this whole phosphate on Venus kind of reopened people's attention to it so sometimes no sometimes there's puzzles and people just life could explain all this but they just don't go

01:23:22 there sorry go ahead Lisa I think one other thing to bring in the excellent planets in here right so we have the Earth and we have Venus and our best explanation is that uh Venus could have been like the Earth before then it got hotter hotter hotter it lost all its water into space right and then it ended up a sweetness but what I find very interesting in the search and we have been talking about the search for Life mostly right but we don't understand the evolution of a rocky planet very well we have some data for our own Planet but for example how does Earth get to Venus

01:23:53 and now these exoplanets these Rocky worlds there are some that are closer to their star meaning they get more energy than the earth status and so what we can do is we can slop in basically those as moments in time between Earth and Venus Venus gets a lot more energy right and so when we get to see those planets in addition to a of course are they still showing signs of Life that'd be amazing because that tells you about the future possibility of earth when it gets hotter

01:24:24 and hotter but also how does an earth in the future transition to Venus and did Venus ever have potentially the conditions for liquid water because there's new modeling because of you know the phosphor non-venus and other things that actually super fascinating that indicates that maybe there's a certain if a planet never cools down to a certain level and they assume then Venus didn't and that doesn't mean that's true

01:24:54 it's just like a really interesting new research area then you would never get an ocean and then you will always have just order in the atmosphere because the beginning it's hot because things actually Collide right and then if you never get cool enough to form this first ocean you just lose the water like this and it's it right you have two paths in these new models that might be right or wrong that say Okay a rocky planet can be like super hot immediately or if it forms an ocean and then it becomes like an earth and then we don't know what's happening

01:25:25 later but this is because of all the new things we find and I'm sure also because of phosphate on vedis and also because of these planets we find and that's a completely new area of research that would have never gotten to because we didn't have any data that we could compare these models to and sometimes I think we shelf things up to the point where we have new data to actually tell us yes or no on some of these cases and so I think learning about how rocky planets

01:25:56 work in the first place going back to how our Rock Records becomes more debatable the further you go back in time is also to me an amazing part of this search for life so even if people are not caring about life in the universe caring about how our rocky planets work and how the future of the earth should potentially work is actually I think a really cool part of this journey yeah I think we should maybe yeah I would like to open it up for a question but also

01:26:27 but just before we do if for any of you since we covered a lot of ground we can't do everything but if if any of you have if there's something we just haven't said or that is a topic or an aspect that we have in common these guys have been very patients I'd say one thing um I'm not sure what life is I we have this concept of biological activity and all this sort of thing which clearly interacts with chemistry and physics

01:26:58 right if you look at the history of science we it was actually largely due to astronomy that we figured out that gravity Works outside the solar system outside the planet and Beyond um and then we learned that chemistry works pretty much exactly the same way it does here um through astronomy universally what we do not know is whether there's anything Universal about biology whether DNA has

01:27:28 any meaning in another environment whether there's another mechanism to have activity that you know metabolizes things and certainly you could claim that computers metabolize things so that the concept of life I think is a very deep question but that is Remains the one area of science we have no concept of whether it is at all Universal in the sense that we have it here now we all say we know life when we see

01:27:59 it you see a worm wiggling around you say it's alive right but if you saw you know a river wriggling around in a funny way on a planet would you think that's alive I don't know so that's a that's a very good it's a good reminder it's salutatory to just have that perspective on the biology of this with all these incredible astronomical experiments underway and planned but yes let's let's hear from our gold people are pursuing is to find the

01:28:29 kind of life that you understand yes yeah yeah and that would be good enough we don't need to find the weird biology fundamental discoveries in history of people oh yeah I mean it put there's no question if anyone wants to come up to the microphone here sure and ask a question and while you're thinking about that I want to pose one question that going back to the pan spurbia the concern about Pam spermi as being an explanation for why we've if we find something on mars or Venus that that could be the explanation um I'm a little bit I don't know enough

01:29:01 about this that's why I'm asking you also but aren't the folks who think that panspermia accounts for life on Earth but you can flip it around right you could say that life started on Mars right and potentially arrived on Earth I think it's just way cooler to be a martian yeah I think I totally agree with that and then it goes much easier that way because yeah pulling you in Mars is less right yes Venus has got a thick atmosphere is more massive and you're heading outward so I think that the rates are very different between those two pads I'm wondering how

01:29:32 different we you were explaining earlier David that you know things would have to look quite different for us to think that Pam spermi doesn't explain it but how different because you know even if the let's say there's something like DNA but not DNA you could say that was part of Prebiotic Evolution and you know there was it was a common source and then they'd be split apart I mean I'm not sure I don't know the answer to it it could have panspermia to create all the life in the solar system right and it came from outside and then you've got

01:30:04 four billion years of evolution yeah where you make up your own can I just point on this and I completely agree that this is the the the the the idea right from outside sorry I'm just like Drawing the Line at outside because you have to hit this thing and there's a lot of space between Stars remember like the cookie and then you have two football fields to the next door so you're jumping to pants yeah and I think there's the problem you have to think about the volume

01:30:35 and we have such troubles getting our missions to the next planet over in this cookie right so it's not a slam dunk that you're going to hit the planet if this one is like no no football feels away so so inside the solar system that wasn't the point way easier to make what I was trying to say was that no matter where this crap comes from it has to originate somewhere right this the complex chemistry and physics of our bodies which we describe as biology

01:31:05 which includes crap by the way yes it's got quite a lot of it and cockroaches yes it has to have grown up come about somewhere um you know unless you don't believe in the Big Bang and we've been here for in you know the universe is infinitely long in time and silly has to start but then still it has to start somewhere a lot of time is infinite so we we have a number oh my goodness is there a lot of questions from our online audience

01:31:36 um okay let me ask this one first I don't think we'll be able to get through them all and there's actually one with a graph oh I'm sorry the graph is a uh an account of the responses to the original okay that's what that was I thought someone embedded some tables and said please respond to us these are high level questions exactly all right so this is from Laura Sanya since the James Webb Telescope only detects infrared light why doesn't it act as a filter blocking out most of the Stellar Spectrum thus allowing us to see exoplanets around brighter Stars it's

01:32:09 not able to block out light but not enough for planets in as we've tried to explain it uses a technique where the planet goes in front of the star and some of the Starlight shines through the atmosphere so all that blocking is happening already before the light gets to the telescope no I think the question is is not it's slightly different there there are coronagraphs on the James Webb Telescope and uh whoever made this point makes a very good one that um many many stars are actually fainter in the infrared than they are

01:32:40 um then the planets actually tend to emit more light in the infrared than they do in the optical and so the contrast between your stars especially a sun-like star and something like a Jupiter is much smaller it's much easier for you to block the light of that star out so you can see the planet itself which is not true for mdorfs which tend to Peak in first which around one micron yeah it's still true with emptorps I think another way to answer this

01:33:11 question is like uh going back to what Chris said when we made the James Webb Space Telescope exoplanets were not known yet nobody knew about it so the James Webb Space Telescope was not designed to have anything on board that could block out the star to the level that we could see a planet around it we just didn't have the time because we didn't know they were there and so there is some of it on it but not good enough to find like a planet and characterize it with the James Webb by blocking out the Stella lights well we'll see okay

01:33:42 we'll see for the big ones it probably will work I'll have to mention that the people who've sent in some questions all seem to have names that a Klingon might have something to do with it anyway the question's been answered yes exactly all right that that question I was corrected by Alex our coordinator was from loraziana um Optimus Prime opportunities yes

01:34:16 that's the name of the questioner um as it's impossible to know for sure that life doesn't exist if in fact it doesn't uh do you think we'll ever give up on the search for life after a very very very long time if we don't find anything in that time I'll just say never works we talked about the Viking experiments people are going to just keep searching or think of orcetti yeah I mean Jill Tarter she's a trooper so it's 60 years you know in big silence yeah keep doing it it's getting better

01:34:46 one answer to this question and it's yes it's out there if you say no you you well I think part of the answer to the question is right is in this field that's so much driven by technology and instrumentation as long as you're doing better and better experiments yes yes no but your head against a wall but we're getting the incredible tools to do this and maybe at some point if you plateau out and the public turns its back on funding science and so no fancy toys for astronomers

01:35:17 well I think that also explains why you know all of you expressed I think a healthy sort of scientific skepticism which is absolutely appropriate in a situation like this but David you said especially emphasized that early on and I'm thinking our entire talk is about looking for life and right I mean there seems to be and there's a lot of money being uh spent on this effort right people really have a strong bias in favor of the answer becoming ultimately yes that doesn't mean we can't be Skeptics at the same time right I think

01:35:48 it must be I think yeah yeah but I think in a way we are in a better position than people before us were because it could have turned out that only one in 50 000 Stars Harbors upon it and Kepler showed us so that's not true right so every fifth one has a potential small right distance right and now the question is is it interesting enough to know that you found these in these places that could be potential Earth to go investigate right that's basically the line where we're at and then the

01:36:19 next question is if we don't find nothing what does that mean and the problem is that if you look at life on the Earth first paper uh for about two billion years it doesn't leave science in the atmosphere that are not also easily explainable by geology it does it makes CO2 it makes CH4 methane and CO2 right it's bacteria that does it but when you see it from remote you won't be able to tell the difference and so there you go back to Carl Sagan

01:36:52 extraordinary discoveries need extraordinary evidence this is why we being very conservative in a way that's where we started out on right that we not just we are looking for everything absolutely everything we can explain but to say that we found something that indicates life we have to have no other explanation then there's life and this is where your question goes back to when do you stop you now have these amazing places that could potentially be like there is so much to learn do you now say

01:37:25 ah I found the place where I could go and look I'll go home and do something else or do you say onwards it's just you know the difficulty of interpreting a null result Michaelson Morley was a null result but it's changed physics forever the no result in this field it's really hard to put your arms around that I'm not sure I take it for granted as much that we'll always continue just that we've seen it with seti you know funding Federal funding was cut from certain it didn't stop people from doing it though

01:37:55 they still kept doing it but I don't think we should um take it for granted that we will always be able to build these large Expressions you know is will people keep funding it versus well people keep looking it takes a lot of effort from science communicators and events like this to try and uh be transparent about what is happening in the field and try and convince people why it's exciting but it it's not impossible because there's been Dark Ages in our history where science went the opposite direction it's not impossible that we would give up on such things or at least the the resources

01:38:27 were no longer available to do that kind of work just as we congregated the group of us before the we started the panel you mentioned that the number of students enrolling in astronomy has been really going up and do you think that's related to this issue in some way or I thought that and then I looked at granted Mission the people who actually applied to grad school at Columbia and and the fraction of people who want to do exoplas is still quite small so there's the you know there's we have like 350 applications for five places last year which is crazy

01:38:58 um and of those you know there's 250 or something who want to do galaxies cosmology or Stellar physics so you can't I mean maybe they were inspired at some point from exopaths I don't know but there's a lot of there's a lot of young people who are interested in lots of other questions in astronomy besides from life by expanding the sample like we did the same granted Mission at Cornell and at Cornell uh it just like my my colleagues are not

01:39:30 very happy with me they were like everyone wants to do exoplanets stop doing the Carl Sagan Institute Outreach right we want the other people to come to Cornell as well what is fine right as David was saying there's a lot of interest in the in in the young people and that's what it should be they should be interested in everything and then I think you get a bit of a fluctuation on one year you get a very exoplanet heavy saying we we did like if you would have asked me instead of David I would have said yes ours is like blown over with

01:40:02 the James Webb and we have people who are in the James Webb instrument teams that have had some press releases and so on so I think this is maybe why we had uh quite a few people being interested so I would have said yes it's crazy but I think it's really good that David brought this up too it's it's not always right I think it's nicely distributed but I think a lot of people that I know who would not have considered astronomy and physics are considering it because

01:40:34 planets in the diversity of what you need to know biology chemistry geology astronomy it appeals to them from wide range somebody who who said I want to know if there's life in the universe can come from it to it from a biology from a geophysics background for example right now I have two postdocs in my lab that are geophysicists and one postdocs who's a microbiologist that's we're sitting together and we're discussing planets right it's a wider range of interest

01:41:04 that exoplanets could potentially help you cover than for example black holes we should remind everyone is that this is core astronomy expertise but astrobiology is a sort of Renaissance subject because it's very interdisciplinary and the NASA the ABS icon meetings every two years uh resisted during parallel sessions they made everyone from their discipline geophysicist astronomer chemist biologist speak to all the other disciplines and you know and bring

01:41:36 everyone along and that's a that's a that's a rare thing now in science at all to be that way just to keep trying to do that so it's one of the little niches of astronomy if you like that subfields that is uh you know holds to this standard of interdisciplinarity because it's the stuff you don't know from that adjacent field you know from the geologist telling you how much free oxygen you might get in and planetary atmosphere oh really six eight percent it's a little scary um whatever so whatever it might be so

01:42:06 so we have the results of their online questionnaire and I think of course it's a little bit of a biased sampling because these are people who are strongly interested in the topic but as far as and I think this comes close to what I observed oh I got another message forgive me um what I observed here when people raised their hands with their cards here the existence of some form of life beyond Earth is almost certain was 52.2

01:42:36 percent um very unlikely it looks like it's about six percent um the next question the existence of intelligent life on Earth it dropped to 35 percent said almost certain 26.1 said very likely and 26.1 also said likely and then lastly what would the news be like right and 52 said the scientific discovery of the century

01:43:06 that's right yeah that's that's uh go tell that to Congress and I think it's part of this enthusiasm we're talking about in general yeah so we that's our time we're wrapping up right I think I think that's it I want to thank everyone for a spectacular uh Roundtable and thank the audience for their attention [Applause] thank you

01:43:38 foreign