Sara Seager: Search for Planets and Life Outside Our Solar System | Lex Fridman Podcast #116
the following is a conversation with sarah seeger a planetary scientist at mit known for her work on the search for exoplanets which are planets outside of her solar system she's an author of two books on this fascinating topic plus in a couple days august 18th her new book a memoir called the smallest lights in the universe is coming out i read it and i can recommend it highly especially if you love space and are a bit of a romantic like me it's beautifully written she weaves the stories of the tragedies and the triumphs of her life with the stories of her love for and research on exoplanets which represent our hope to find life out there in the universe quick summary of the ads three sponsors public goods that's the new one power dot and cash app click the links in the description to get a discount it really is the best way to support this podcast as a quick side note let me say that extraterrestrial life aliens i think represent our civilization longing to make contact with the unknown with others like us or maybe others that are very different from us entities that might reveal something profound about why we're here the possibility of this is both exciting and at least to me terrifying which is exactly where we humans do our best work if you enjoy this thing subscribe on youtube review it with five stars on apple podcast support it on patreon or connect with me on twitter at lex friedman as usual i'll do a few minutes of as now and never any ads in the middle that could break the flow of the conversation i try to make these ad reads interesting if you do listen but if you like i give you time stamps so you can skip to the conversation but still please do check out the sponsors by clicking the special links in the description it's the best way to support this podcast this show is sponsored by public goods the one-stop shop for affordable sustainable healthy household products their products have a minimalist black and white design that i find to be just 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conversation with sarah seeger when did you first fall in love with the stars i think i've always loved the stars one of my first memory is of the moon i remember watching the moon and i was in the car with my dad who my parents were divorced and he was driving me and my siblings to his house for the weekend and the moon was just following me just had no idea why that was yeah so like looking up at the sky and there's this glowing thing how do you make sense of the moon that at that age at age at like age five there's just no way you can i think it's one of the great things about being a kid it's just that curiosity that that all kids have you know i was thinking because there's these uh uh almost uh out there ideas of of that our earth is flat uh floating about on the internet and it made me think you know when did i first realize that the earth is um like this ball that's uh flying through empty space i mean it's terrifying it's uh awe-inspiring i don't know how to make sense of it it's uh it's hard because we live in our frame of reference here on this planet yeah it's nearly impossible none of us are lucky to go to see the curvature of earth i mean do you remember when you realized understood like the physics like the layout of the solar system this is it was it like did you first have to take physics to really uh like high school physics to really take that in i think it's hard to say i had this book when i was a child it was in french i grew up in canada where french is supposedly taught to all of us english-speaking canadians and it was this friend book in french was about the solar system and i just love flipping through it it's hard to say how much you know you or i understand when we're kids but it was really a great book what about the stars when did you first learn about the stars like i do have this very incredible distinctive memory and again it had to do with my dad he took us camping now my dad was from the uk and he was the type who you'd find wearing a tie on weekends so camping was not in his sphere his comfort zone we had a babysitter every summer we got a baby we every summer we had a babysitter and one summer we had tom he was barely older than we were he was 14 my brother was 12. i would have been 11 or 10 maybe and we went camping because tom said camping's the thing we should we should try it and i just remember i didn't aim to see the stars but i walked out of my tent in the middle of the night and i looked up and wow so many stars the dark night sky and all those stars just like screaming at me i just couldn't believe that honestly like my first thought was this is so incredible mind-blowing like why wouldn't anyone have told me this existed can anyone else see this have you have you had an ex have you experienced like that with anything like yeah i've had that i mean i don't know if maybe you can tell me if it's the same uh i've had that with robots uh there's a few robots i've met where i just fell in love with this like is anyone else seeing this is anyone else seeing that here in a robot is our ability to engineer some intelligent beings intelligent beings that we could love that could love us that we can interact with in some rich ways that we haven't yet discovered like uh almost like when you get a puppy it needs to have a dog and there's this uh immediate bond and love and on top of that ability to engineer it it was you know i had to just pause and and hold myself i imagine i don't have kids i imagine there's a magic to that as well or it's a totally new experience it's like what well yeah the stars though unlike kids or the puppy it's only a good thing so you felt you weren't terrified like it's to me when i look at the stars it's almost paralyzingly scary how little we know about the universe how alone we are i mean somehow it feels alone i'm not sure if it's a it's just a matter of perspective but it feels like wow there's billions of them out there and we know nothing about them and then also immediately to me somehow mortality comes into it i mean how did that make you feel at that time i think as a child without articulating it i felt that same way just like wow this is terrifying what's out there like what is this what does it mean about us here uh you you're a scientist an exo world class scientist planetary scientist astronomer uh now i'm a bit of an idiot who likes to ask silly questions so some questions are a little bit in the realm of speculation almost philosophical because we know so little and one of the awesome things about your work is you've actually put data and real science behind some of the biggest questions that we're all curious about but nevertheless many of the questions might be a little bit speculative so on that topic uh just in your sense do you think we're alone in the universe human beings do you think there's life out there well lex the funny thing is is that as a scientist i so don't even want to answer that you do you really don't i will answer them yeah but i just loved you resisted naturally yeah we naturally resist that because we want numbers and hard facts and not speculation but i do love that question it's a great question and it's one we all wonder about but i have to give you the scientist answer first yeah sure which is we'll have the capability to answer that question soon even starting soon how do you define soon how do i define science what do you so much happen in the last 100 years right right and there's a difference right if it's 10 years or 20 years or 100 years yeah there's a difference in that well soon could be a decade or two decades and then by the way journalists usually don't like that or the people want like tomorrow they want the news but what it's going to take is telescopes space telescopes or very sophisticated ground or space telespace telescopes to let us study the atmospheres of other planets far away and to look what's in the atmospheres and to look for water which is needed for life as we know it to look for gases that don't belong that we might attribute to life so we have to do some really nitty-gritty astronomy so the the promising way to answer this question scientifically is to look for hints of life that's where like many of your ideas come in of what kind of hints why might we actually see about this right right that's exactly what we need to do and i like the word you chose hint because it's going to be a hint it's not going to be a 100 percent yay we found it and then it will take future generations to do more careful work to hopefully even find a way to send a probe to these distant exoplanets and to really figure this out for us i mean we'll talk about the details those are fun but like uh back to the speculation zoomed out big pictures yes i believe absolutely there is life out there somewhere because there the vastness of the universe is incredible it's so breathtaking when we look at the night sky if you can go to that dark sky you can see you know many many hundred or even if you have good eyesight and you're somewhere very dark you could see thousands of stars but in our galaxy we have hundreds of billions of stars and our universe has hundreds of billions of galaxies so think about all those stars out there and even if planets are rare even if life is rare just because the number of stars is so huge things have to come together somewhere someplace in our universe yeah it's so amazing to think that somebody might be looking up on another planet in a distant galaxy and get back to in our lifetime at least the short term we have to we only have the nearest stars to look at it's true that there are so many stars so many hosts for planets that might have life but in the practical question of will we find it it has to be a star quite close to earth like a few light years tens of light years maybe hundreds of light years and by the way you've introduced me to a tool of eyes on exoplanets i think that nasa has put together isolated clinics that's it software you guys that's so cool uh but anyway uh can you give a sense of like who our neighbors are like you said uh hundreds of light years like how many stars are close by at like what what's our neighborhood like we're talking about five ten stars that we might actually have a chance to zoom in on i'm talking about maybe a dozen or two dozen stars and those are that's with planets that look suitable for us to follow up in detail for life right one thing that's really exciting in this field is that the very nearest star to earth called proxima centauri it's part of the alpha centauri star system cool name by the way yeah approximately whoever names them nearby okay but it sounds cool proxima proxima centauri appears to have a planet around it that's an earth map about an earth mass planet in the so-called habitable zone or the goldilocks zone of the host star so think about how incredible that is like out of all the stars out there even the very nearest star has planets and has a planet of huge interest to us yeah okay so can we talk about that planet what uh uh what what does it mean to be maybe possibly habitable habitable uh you know what uh what is how does size come into play how does um you know what we know about gases and what kind of things are necessary for life you know what are the factors that you make you think that it's habitable and by the way i mean maybe one way to talk about that is people know about the drake equation which is a very high level almost framework to think about what is the probability that correct me if i'm wrong that there's life out there uh and intelligent life i think i don't know but then the equation named after you now which i think nicely focuses in on the more achievable and interesting uh part of that question which is on whether there is habitable planets out there or how many i guess right so the funny thing is was one time i met frank drake and i asked if he minded if i took his equation and kind of revamped it for this new field of exoplanet astronomy he was totally cool with it he's he got total approval well maybe uh okay so i'm not sure if he'd actually read the stuff about my equation but he was cool with it he was cool with it uh okay so i just said like 15 different things but maybe can you tell from your perspective what is the drake equation and what is sorry the seeger equation sure well the drake equation as you said it's a framework it's a description of the number of civilizations out there of intelligent beings that are able to communicate with us by radio waves so if you think of like if you think of the movie contact you've seen contact right we're hoping to get we're listening in actually it's an active field of research listening to other stars at radio wavelengths hoping that some intelligent civilizations are sending us a message and the drake equation came like at the start of that whole field to put the factors down on paper to sort of illustrate what is involved to kind of estimating and there's no real estimate or a prediction of how many civilizations are out there but it's a way to frame the question and show you each term that's involved so i took the drake equation and i called it a revised drake equation and i recast it for the search for planets by more traditional astronomy means we're looking at stars looking for planets looking for rocky planets looking for planets that are the right temperature for life looking for planets that might have life that outputs gases that we might detect in the future it's the same spirit of the drake equation it's not going to give us any magic numbers so i'm going to say hey here's exactly what's out there it's meant to kind of guide guide of where we're going although the jerk equation did i mean the initial equation proposed actual numbers for those variables oh yes the equation proposed numbers and you can still plug your own numbers in and there's this really cute website that lets you for both the drake and my revised equation plug in some numbers and see what you get so yeah so okay so what are what are i mean what are the variables but maybe also what are like the critical variables so in my equation i set out to what are the numbers of inhabited planets that show signs of life by way of gases in the atmosphere that can be attributed to life i could just walk through the terms that's super simple the first thing i say is what are the number of stars available and it's not that those trillions and trillions of stars everywhere it's what are available to like a specific search and so for example the mit led nasa mission tess is surveying the sky looking for all kinds of planets but it can also it also has stars it has about 30 000 red dwarf stars so we just take a number of stars that a given survey can access so that's what the number of stars is then i wanted to know what kind of stars are uh quiet a quiet i called it a fraction of those stars that is quiet in the case of tess the way it's looking for planets is planets that transit the star they go in front of the star as seen from the telescope but it turns out that some stars are very active they're variable and they brighten and dim with time and that interferes with our observation i apologize to interrupt so it's a transiting planet so you're really looking for a black blob essentially that blocks the light we're looking for a black blob that blocks light and then trying to say something about the size of the planet uh from the frequency of that black blobs appearance and the size of that black blob that kind of thing yeah but let's just say that out of all the stars there are accessible to whatever telescope some of them are just bad for whatever reason you're not gonna be able to find planets around them so i need to know the fraction of those that are that are good so again we have the number of stars the fraction of them that we can actually find planets around um and by the way is our sun set one such is is our sun quiet our sun is quiet okay so i have actually two terms one describes how quiet they are and one is if we can find a planet around that star these transiting planets for example not all planets transit because the planet would have to be orbiting that star in this kind of plane as viewed from you but if a star is for example orbiting in the plane of the sky it will never transit it will never go in front of the star so in that case we have to have a fraction that takes into account that kind of geometric factor and hopefully it's right i mean you can assume that it's uniformly distributed hopefully yes we can assume and there's evidence that it's uniformly distributed yes so then the next so all of these factors so far number of stars accessible to whatever telescope you're thinking about how many stars are quiet fractional stars that are quiet fraction that are observable in this case for the geometric factor those are all things we can measure and there's one more term in the seeger equation we can measure i call it fraction of planets in the habitable zone because believe it or not we have a handle on that for a certain set of stars we know from our the kepler space telescope that operated for a number of years we have estimates for how many planets are in the so-called habitable zone of the host star for a certain type of star so all those we have measurable and then like the drake equation itself there are some terms we can not measure and those ones i call them fl fraction of all those planets that have life on them because we don't know what that is and fs i called for spectroscopy the fraction that have we can use our telescope and instrument tools to look for light actually fs was the ones that the planets that that have life that actually gives off a gas a useful gas that might accumulate in the atmosphere so we could eventually observe it uh how do the fl and fs interplay so these are separate terms separate terms and so so for example you could imagine so for example you could imagine life like us humans we breathe out carbon dioxide but our planet earth we already have a lot of carbon dioxide on it well we have hundreds of parts per million but it has a really strong signal so us humans breathing out carbon dioxide it's not helpful for any intelligent beings that are looking back at earth because there's already a lot of there's already enough carbon dioxide we're not adding to it so if there is life on a planet and it's outputting a boring gas that's not helpful for us to uniquely identify as being made by life versus just being there anyway then it's not helpful so i separated those two terms out soon i think we'll have evidence that planets that can support life at least are common so okay this is such an awesome topic i have a million questions uh what okay i know it's a little bit of speculation but what's your sense about that uh i think fs which is like that uh life would produce interesting gases that would be able to detect like is there one is there scientific evidence and and second is there some intuition around life producing gases detectable hints in terms of chemistry so interestingly enough that entire question relates to i'm gonna say almost my life's work yeah the work i'm doing now and the work i'm doing for the next 20 years and i wish i could give you a concrete number like one percent like on the worst days it's one percent let's say in my mind you know in the best days it's like 80 and i could actually go into a lot of detail here but i'll just give you the simplest things so first of all we make an assumption that like us and our life here on earth life uses chemistry so we use chemistry because we eat food we breathe air and we have metabolism that to break down food to get energy to store energy and then ultimately to use it and all life here has some kind of byproduct in doing all that some kind of waste product that goes into the atmosphere so i like to think that life everywhere uses chemistry some people have imagined like uh let's imagine like a windmill like mechanical energy just getting energy and using it without storing it and if there was life like that it might not need to output a gas so we make this basic assumption of chemistry that's the first thing the second more complicated thing that i and my team work on is what happens to the gas once it is produced by life it goes into the atmosphere and a lot of gas is just destroyed immediately actually by ultraviolet radiation or by oxygen oxygen's incredibly um destructive to a lot of gases so the gas can be produced by life but it could be just completely destroyed by its environment i guess we should pause on that that you mentioned your life's work i mean this is just a beautiful idea that uh it's kind of paralyzing when you look out there and you wonder is there a life out there a b is it's the first paralyzing actually before i encountered your work i feel like an idiot but you know uh it feels like there's no tool to answer that question and then what you kind of provided is this cool idea that it might be possible to answer that by looking at the gases i mean that's a really interesting that's a beautiful idea and uh yeah so we could just pause on like that's as a powerful tool i think that uh to build the intuition wrong because i was totally clueless about it and that was kind it's kind of exciting i mean i'm sure there's a folks probably early on in your life uh who were very skeptical about this notion well maybe i'm not sure but it's generally you would want to be skeptical it's like well all these kinds of other things could generate gases you know all those oh that's so true and that's a big part of this growing field is how to make sure that this gas isn't produced by another effect but i do want to you know again pausing on that and going back a bit it's incredible to think but like at least almost 100 years ago there's a record of someone talking about the idea of a gas being an indicator of life elsewhere oh that idea was floating about it was totally floating about and it comes down to oxygen which on our planet fills our atmosphere to 20 by volume and you know we rely on oxygen to breathe you know when they you hear about the people on mount everest running out of air they're really running out of oxygen well they're running out of oxygen because the air is getting thinner as you they climb up the mountain but without plants and bacteria there's plants that bacteria that also photosynthesizes and produces oxygen as a waste product without those we would have virtually no oxygen our atmosphere would be devoid of oxygen so yeah what uh if you were to analyze uh earth is oxygen the strong indicator here oxygen is a huge indicator and that's what we're hoping that there is an intelligent civilization not too far from here around a planet orbiting a nearby star with the kind of telescopes we're trying to build and they're looking back at our sun and they've seen our earth and they see oxygen and they they probably won't be like 100.00 sure that there's life making it but if they go through all the possible scenarios they'll be left with a pretty strong hint that there's life here yeah okay but how do you detect that type of gases that are on the planet from a distance and that's going back to that that's what people were skeptical about when i first started working on exoplanets long time ago people didn't believe we would ever ever ever study an exoplanet atmosphere of any kind and now dozens of them are studied there's a whole field of people hundreds of people working on exoplanet atmospheres actually wow but first there was a point where people didn't even know there was exoplanets right when was the first exoplanet detected the first exoplanet around a sun-like star anyway was detected in the mid-1990s that was a big deal i kind of vaguely remember that well at the time it was a big deal but it was also incredibly controversial because in exo you know planets we only had one example of a planetary system our own solar system and in our solar system jupiter our big massive planet is really far from our star and this first exoplanet around a sun-like star was incredibly close to its star it's star so close that people just couldn't believe it was a planet actually so maybe zoom out what the heck is an exoplanet an exoplanet is our name like is the name that we call a planet orbiting a star other than our sun right extra solar i guess is the number you can call it extrasolar exoplanet is simpler but i think it's worth pausing to remember that each one of those stars out there in our night sky is the sun right and you know our sun has planets mercury venus earth mars etc and so for a long time people have wondered do those other stars or other suns have planets and they do and it appears that nearly every star has a planet has a planet we call exoplanet and there are thousands of known exoplanets already so there's already yeah like there's so many things about space that it's hard to put in into one's brain because it starts filling it with awe so yeah if you visualize the fact that the stars that we see in the sky aren't just stars they're like they're sons and they very likely as you're saying will have planets around them there's all these planets roaming about in this like dimly lit darkness with potentially uh life i mean it's just mind-blowing but um maybe can you give a brief like history of and like of discovering all the exoplanets so there's no exoplanets in the 90s and then there's a lot of exoplanets now so how did that come about so many planets how did it come about well maybe another way to ask is what is the methodology that was used to discover them i can say that but i'd like to just say something else first where so in exoplanets you know the line between what is considered completely crazy and what is considered mainstream research legit is constantly shifting this is awesome yeah so before when i started on exoplanets it was still sketchy like it wasn't considered a career or a thing a place where you should be investing and right now now today it's so many people are working in this field a good i don't know at least a thousand probably more i don't know if that sounds like a lot to you but it's a lot no it's a legitimate field of inquiry yeah legitimate field of increase and what's helped us is everything that's helped everyone else it's software it's computers it's hardware it's like our phones you have a fantastic detector in there like they didn't always have that i don't know if you remember the so-called olden days we didn't have digital cameras we had film you take a film camera you send the film away and eventually it comes back and then you see your pictures and they could all be horrible yeah so yeah it sent me digital it just changed everything data changed everything yeah and so one thing that really helped exoplanets were detectors that were very sensitive because when we're looking for this the transiting planets what we're doing is we're monitoring a star's brightness as a function of time it's like click taking a picture of the stars every few seconds or minutes and we're measuring the brightness of a star like every frame and we're looking for a drop in brightness that's characteristic of a planet going in front of the star and then finishing its so-called transit and to make that measurement we have to have precise detectors and uh the the detectors that are making the measurement can you do it from earth is it uh are they floating about in space like what kind of telescope both so on the ground people are using telescopes small telescopes that are almost just like a glorified telephoto lens and they're looking at big swaths of the sky and from the ground people can find giant planets like the size of jupiter so it's about 10 to 12 times the size of earth we can find big planets because we can reach about one percent precision so i'm not sure how much technical you want to get but well yeah well how many pixels are we talking about like what uh you mentioned phones there's a bunch of uh megapixels i think so for exoplanets you want to think about it as like a pixel or less than a pixel we're not getting any information but to be more technical our telescope you know spreads the light out over many pixels but we're not getting information we're not tiling the planet with pixels it's just like a point of light or in most cases we don't even see the planet itself just the planet's effect on the star but another thing that really helped was computers because transiting planets are actually quite rare i mean they don't all go in front of their star right and so to find transiting planets we look at a big part of the sky at once or we look at tens of thousands or hundreds of thousands or even in some cases millions of stars at one time and so you know you're not going to do this by hand going through a million stars counting up the brightness we so we have computer software and computer code that does the job for us and looks for a you know counts the brightness and looks for a signal that could be due to a transiting planet and you know i just finished a job called uh deputy science director for the mit led nasa mission test and it was my purview to make sure that we got the planet candidates the transiting light curves out to the community so people could follow them up and figure out if they're actual planets or false positives so publish the data so that people could just uh yeah publish data all the all the data scientists out there could crunch and see if they can exactly they can discover something and in fact the nasa policy for this mission is that all the data becomes public as soon as possible so anyone could act it's not as easy as it sounds though to download the data and look for planets but there is a group called planethunters.org and they take the data and they actually crowdsource it out to people to look for planets yeah and they often find fine signals that our computers and our team missed so we mentioned exoplanets what about earth like or i don't know what the right distinction is if is it habitable or is it earth-like planets but what are those different categories and how can we tell the difference and detect each right right so we're not at earth-like planets yet all the planets we're finding are so different from what we have in our solar system they're just easier planets to find but like in which way for example there could be a jupiter-sized planet where an earth should be we find planets that are the same size as earth but are orbiting way closer to their star than mercury is to our sun and they're so close that because close to a star means they also orbit faster and some of these hot super earths we call them their year their time to go around their star is less than a day and they're heated so much by their star they're heated so much by the star we think the surface is hot enough to melt rock so instead of running out by the bay or the river you'll have like liquid lava there'll be liquid lava lakes on these planets we think and life can't survive way too hot the molecules for life would just be molecules needed for life just wouldn't wouldn't be able to survive those temperatures we have some other planets one of the most mysterious things out there factoid if you will is that the most common type of planet we know about so far is a planet that's in between earth and neptune size it's two to three times the size of earth and we have no solar system counterpart of that planet that is like going outside to the forest and finding some kind of creature or animal that just no one has ever seen before and then discovering that is the most common thing out there and so we're not even sure what they are we have a lot of thoughts as to the different types of planet it could be that people don't really know i mean what are your thoughts about what it could be well one thought and this is more when we want to be rather than might be is that these so-called mini neptunes we call them that they are water worlds that they could be scaled up versions of jupiter's icy moons such that they are planets that are made of more than half of water by mass so yeah and what's the connection between water and life and the possibility of seeing that from a gas perspective okay so all life on earth needs liquid water and so there's been this idea in astronomy or astrobiology for a long time called follow the water find water that will give you a chance of finding life but we could still zoom out and the kind of the community consensus is that we need some kind of liquid for life to originate and to survive because molecules have to react if you don't have a way that molecules can interact with each other you can't really make anything and so when we think of all the liquids out there water is the most abundant liquid in terms of planetary materials there really aren't that many liquids like i mentioned liquid rock way too hot for life we have some really cold liquids like almost gasoline like ethane and methane lakes that have been found on one of saturn's moons titan that's so cold though and for exoplanets we can't study really cold planets because they're just simply too dark and too cold so we usually so we're usually just left with looking for planets with liquid water and to your point it's remember as we talked about how planets are less than a pixel in in that way to say so we can't see oceans on planet we're not going to see continents and oceans not yet anyway but we can see gases in the atmosphere and if it's a small rocky planet and this is going into some more detail it's a small if we see a small rocky planet with water vapor in the atmosphere we're pretty sure that means there has to be a liquid water reservoir because it's not intuitive in any way but water is broken up by ultraviolet radiation from the star or from the sun and on most planets when water is broken up into and o the h the hydrogen will escape to space because just like when you think of a child letting go of a helium-filled balloon it floats upwards and hydrogen's a light gas and will leave from earth leave from the planet so ultimately if you have water unless there's an ocean like a way to keep replenishing water vapor in the atmosphere that water vapor should be destroyed by ultraviolet radiation got it so there's a okay so there's a need for liquid i mean i guess what is water well is water essential is other liquids i mean the chemistry here is probably super complicated there's not it does but you know there's not an infinite number of liquids right there's maybe like five liquids that can exist inside or on the surface of a planet and water is the one that exists for the largest range of temperatures and pressures and it's also the easiest type of planet for us to find and study as one with water vapor rather than a cold planet that has ethane and methane lakes what's your personal in terms of solar systems and planets that you're most hopeful about uh in terms of our closest neighbors that you kind of have a sense that there might be uh somebody living over there whether it's bacteria or somebody that looks like us i'm hopeful that every star nearby has has a planet has some life because it almost has to for us to make progress we have to have that dream condition so the dream condition is like life is just super abundant out there yeah the dream yes the dream condition is that life is super abundant and it's based on the thought that if there is a planet with water and continents that it also has the ingredients for life and that the kind of base does the base the base kernel thought is that if the ingredients for life is there life will form that's what we're holding on with the relatively high probability yes that's that's it okay let's go into land of speculation uh what about intelligent life uh us humans consider ourselves intelligent surprisingly or unsurprisingly do you think about from your perspective of looking at planets from a gas composition perspective and in general of how we might see intelligent life and uh your intuition about whether that life is even out there i think the life is out there somewhere the huge numbers of stars and planets i like to think that life had a chance to evolve to be intelligent i'm not convinced the life is anywhere near here only because if it's hard for intelligent life to evolve then it will be far away by definition well the sad thing is uh maybe from the artificial intelligence perspective is it makes me sad there might be intelligent life out there that we're just not like the pathways of evolution can go in all these different directions where we might not be able to communicate with it or even know that or even detect its intelligence or even comprehend its intelligence yeah convince cats are more intelligent than humans that that we're just not able to comprehend the the measures the the proper measures of their intelligence my dog is so funny he's the golden doodle his name's leo we joke that he's either a really dumb dog and so he's not here to defend himself but he's either really dumb or he's a super genius just pretending to be dumb yeah i mean it's possible he's he's a multi-dimensional projection of alien life uh here monitoring uh one of the you know one of the top scientists in the world trying to find aliens just to make sure just just to make sure that humans don't get out of hand that's funny oh i'm definitely going to go in and ask him ask him about that ask him about that he's on to something yeah what might we look for in terms of signs of intelligent life from your toolkit do you think there are things that we should we might be able to use or maybe in the next couple of decades discover that would be different than life that's like bacteria that's primitive life i still love seti search for extraterrestrial intelligence i like to hope that if there is a civilization out there they're trying to send us a message i think like think about it i don't know what are your thoughts like if you think about our earth there's no structure we've built that intelligent civilizations could see from far away there's literally nothing not even the great wall of china and so to think like why would this other civilization build a giant structure that we could see yeah so with seti the idea is that we're both trying to hear signals and send signals right we haven't sent one they call that medi messaging and there's a big kind of fear over medi because do you want to tell them you're here it's kind of this like let's wait till they call us yeah so uh we should have a dating game we have to like how how many days do i wait before i call kind of thing yes it and so but the funny thing is if no one's sending us a message if everybody's only listening how do you make progress that's right and so i mean but there's also there's the voyager spacecraft so we we have these little pixels of uh robots flying out all over the place some of them like the voyager reach out really far and they have some stuff stuff on them okay i just we do we have the voyager but they're not really going anywhere in particular and they're moving very very slowly on a cosmic scale yeah and let me say they're far is kind of silly because yeah it's all relative in astronomy it's all relative yeah yeah i just i so from uh if you look at earth from an alien perspective from visually and from gas composition i wonder if it's possible to determine the degree of maybe um productive energy use i wonder if it's possible to tell like how busy these earthlings are well let's zoom out again and think about oxygen so when cyanobacteria arose like billions of years ago and figured out how to harness the energy of the sun for photosynthesis they re-engineered the entire atmosphere 20 of the atmosphere has oxygen now like that is a huge scale you know they almost poisoned everything else by making this what was apparently very poisonous to everything that was alive but imagine so are we doing anything at that scale like are we changing anything in like 20 of the earth with a giant structure or 20 of this or 20 of that like we aren't actually yeah yeah that's that's uh that's humbling to think that we're not actually having that much of an impact i know but we are because in a way we're destroying our entire planet but it's humbling to think that from far away people probably can't even tell but from the perspective of the planet when we say we're destroying you know global warming all that kind of stuff um what we really mean is we're destroying it for a bunch of different species including humans but like i think the earth will be okay oh the earth will be the earth will remain whatever whatever happened to us the earth will still be here and it'll still be difficult to detect any difference like it's sad to think that if humans destroy ourselves except potentially when you clear war it'd be hard to tell that anything even happened yeah it will be hard to tell from far away that anything happened what about what are your thoughts now this is really getting into speculation land there you've you've mentioned exoplanets were in the realm of you know there's this beautiful edge between science and science fiction that uh some of us a rare few are brave enough to walk i think in academia you were brave enough to do that i think in some sense artificial intelligence sometimes walks that line a little bit um there is so much excitement about extraterrestrial life and aliens in this world i mean i don't know what how to comprehend that excitement but to me it's great to see people curious because to me extraterrestrial life and aliens is at the core a scientific question and it's almost looks like people are excited about science they're excited by discovery discovery right and then the possibility that there's alien life that visited earth or is here on earth now is is uh excitement about discovery in your lifetime essentially i mean what do you make what do you make of that there's recent events where darpa um or dod released footage of uh these um unmanned aerial phenomena they're calling them now uap they got everybody like super excited like maybe there is like what what what's what's here on earth uh do you follow the this world of people who are thinking about aliens that are already here or have visited i don't really follow it they follow me i'd say because in this field if you're a scientist of any kind you get the people contact us me there's a lot of them about hey i have stuff you should see hey the aliens are already here i need to tell you about it and i know there are people out there who really believe there's a psychology to it there's a psychology to it and it's fascinating but okay so it's similar to artificial intelligence but i still but like you i'm still enamored with the point that it is out there and that people believe so strongly and that so many people out there believe i believe and uh i don't know i i i'm not as allergic to it as some scientists are because ultimately if aliens showed up or do show up or have showed up you know these are going to be very difficult to study scientific phenomena like in fact like going back to cats and dogs like i just i think we should be more open-minded about uh developing new tools and looking for intelligent life on earth that we haven't yet found or even understanding the nature of our own intelligence because it kind of is an alien life form the thing that's living you know in our skull it's so true when we don't understand consciousness yeah it's true we don't understand how biology is hard you know unpacking it and working it all out it's a stretch and they say too that our thinking mind is like the tip of the pyramid that everything else is happening under the hood and but what is happening but the thing with so the typical scientists response to you know are there aliens here is that we need to see major evidence not like a sketchy picture of something we need some cold hard evidence and we just don't have that that's exactly right but from my perspective i admire people that dream and i think that's beautiful the thing i don't like there's two sides of the of the folks uh that probably listen to this this podcast is oh those that dream i think is beautiful that uh that wonder what's out there what's here on earth and then the other ones who are very conspiratorial in thinking that stuff is being hidden right becomes about institutions okay i have a funny thing to tell you about that so one of my colleagues had a really good answer to that and it's not me saying this so i can say this but he said look he works with nasa not at nasa he works with government not in the government it's kind of me but he'd say trust me they couldn't hide it if they tried do you know what i'm saying like everybody we're not we're not smart enough or good enough not we or not me or not you but whoever to cover it up it just it's sort of a myth yeah it makes it sad because um the people at nasa the people at mit the people in academia the people in these institutions and yes even in government are often trying they're like just curious descendants of apes they're just they they want to do good they want to discover stuff they're not trying to hide stuff in fact most of them would in terms of leaks would uh love to discover this and release this kind of stuff and there's a did you ever watch this show called the x-files yeah scully and mulder yeah and what i love actually i used to put it up during my talks my public talks there's a picture of a ufo or what looks like ufo and it says i want to believe so that's that's where i think a lot of us are coming from i want to believe and it's so great and one time i put that up and this very very nice couple approached me really nervous afterwards and they said hey can we take you out for lunch sometime and i said sure and they were like the nicest people and just one of many who has an alien alien abduction story and the woman um could never have kids they were older but they didn't have kids which for them was a real source of regret but it was because the aliens who had abducted her had made it so that she couldn't have kids and she had apparently something implanted behind her ear which was somehow unimplanted later and they were just so sincere and they're such a lovely couple they just wanted to share their story that's that's a real whatever that is that's the real thing the mystery of the human mind right is more powerful than any alien or i mean it's uh as interesting i think as the universe and i think they're somehow intricately linked maybe getting a sense of numbers how many stars are there in maybe i don't know what the radius that's reasonable to think about i don't know if the observable universe is like way too big to think about but in terms of when we think about how many habitable planets there are what are the numbers we're working with in your sense what are the scales honestly the numbers are probably like billions of trillions of stars yeah you know in the uk i think i don't know if we do that here but they will call a billion trillion where you put like 1 billion followed by a trillion yeah it's kind of weird but here i don't even know how to say the number 10 to the 20. like if you know what that is that's 1 followed by 20 zeros that's a big number and we don't have a name for that number there's so many per star i think we kind of mentioned this is there a good sense there's probably argument about this but per star how many planets are there is there we don't have that number yet per se you know we're not really there but some people think that there's many planets per star there's this analogy of filling the coffee cup like you know you don't usually just pour one drop you fill it and that planetary systems we see stars being born that have a disk of gas and dust and that ultimately forms planets so the idea this kind of concept is that planets so many planets form too many and eventually some get kicked out and you're left with like a full planetary system a dynamically full system and so there have to be a lot because so many form and a bunch survive that i mean that that makes perfect intuitive sense right like why wouldn't that happen right well there's other thoughts too though these big planets that are really close to the star we think they formed far away from the star where there's enough material to form and they migrated inwards and some of these planets migrating inwards due to interaction with other planets or with the disk itself they may have cleared it out like kicked other planets out of the system so there's a lot of ideas floating around we're not entirely sure and what about earth-like planets is that that's another level of uncertainty that it's a level of uncertainty if we think of an earth-like planet being an earth around a sun in the same orbit an earth-like planet being an earth-sized planet in an earth-like orbit about a sun-like star we're not there yet you know we're not able to detect enough of those to to give you a hard number some people have extrapolated and they will say as many as one in five stars like our sun could be hosting a true earth-like planet wow on the topic of space exploration there's been a lot of exciting developments with nasa with spacex with other companies successfully uh getting rockets into space with humans and getting them to land back uh especially with spacex what are your thoughts about elon musk and spacex crew dragon well working with nasa to launch astronauts what's your sense about uh these exciting new developments well spacex and other so-called commercial companies are only good news for my field because they're lowering the cost of getting to space by having reusable rockets it's just been it's incredible and we need cheaper access to space so from a very practical viewpoint it's all good about getting people there's this dream that we have to go to mars boots on boots on mars what do you think about that you mentioned probes what's the value of humans uh is that interesting to you from both scientific and a human perspective human mostly i think it's such in our desire to explore because part of what it means to be human so wanting to go to another planet and and be able to live there for some time it's just just what it means to be human you know oftentimes in science and engineering big huge discoveries are made when we didn't intend to so often this kind of pure exploratory type of research or this pure exploration research it can lead to something really important like the laser we couldn't really live without that now at the grocery you scan your foods there's surgery that involves involved lasers gps we all use our gps we don't have gps because someone thought hey it'd be great to have a navigation system and so i do support i do i just but i really think it comes primarily just from the desire to explore do you think something there's a lot of criticism and a lot of excitement about mars do you think there's value in trying to go to put humans on mars first of all and second of all colonize mars do you think there's something interesting that might come from there i i'm convinced there will be something interesting i just don't know what it is yet but i don't think i don't think having some commercial value or value in the metric of something useful is really what's motivating us so really uh you see exploration is a long term investment into something awesome that eventually be commercial value yeah i do actually yeah i do so what about visiting okay i apologize but i mean there's an exciting longing to um visit earth-like planets elsewhere so what's the closest uh earth-like planet you think is worth visiting and how how hard is it wow it is very hard i mean our nearest call it earth mass planet it's orbiting a star very different from our own sun an m dwarf star a small red star proxima centauri it's over four light years away and we can't travel at the speed of light we can't even try i mean it would take tens of thousands of years to get there with conventional methods so you know the movies like multi-dimensional yeah this movie passenger have you seen that movie passenger it's about a big spaceship that is traveling to another planet and everyone's hibernating i won't give you the spoiler alert because one person wakes up and then it's kind of a problem okay got it but yeah the multi-generational ships i mean when you think about where we're headed as a species maybe we don't send people maybe we end up sending raw biological materials and instructions to print out humans it sounds kind of far-fetched but already we're printing like liver cells in the lab and beating heart cells we're starting to reconstruct body parts i mean the thing is it is so hard to get to another planet that this thought of printing humans or printing life forms actually could be easier yeah that's somehow so sad to think to think of the idea that we would launch a successful spaceship that has multi-generational like non-human life and it's going to reach other intelligent life and by the time they figure out where it came from human civilization will be extinct wow yeah that is really exciting that's so that's one you there's a there's a tempting thing to think about what are the possible trajectories so uh you know elon keeps talking about multi-uh planetary us becoming multi-planetary species i mean sure mars is a part of that but like the dream is to really expand outside the solar system and it's it's not clear just like as you said like what the actual scientific engineering steps that are required to to take it seems like so daunting so daunting so like this the smart thing seems to be to do the most achievable near daunting task even if there doesn't seem to be a commercial application which i think is colonizing mars but like from your perspective is there some manhattan project style huge project in space that we might want to take on and you've had roles you had scientist hat roles and then you also have roles in terms of being on like committees and stuff determining where funding goes and so on so like is there a huge like multi-trillion we've been throwing the t word around recently a lot but these huge projects that we might want to take on well first of all we want to find the planets like earth first like just even finding those earth-like planets is a billion dollar endeavor billions of dollars endeavor and that's so hard because an earth is so small so less massive and so faint compared to our sun it's the proverbial needle in a haystack but worse and we need very sophisticated space-based telescopes to be able to find these planets and to look look at them and see which ones have water and which ones have signs of life on them yeah the the star shade project that your shade starship yeah this is probably the most badass thing i've ever seen right you know what's interesting so what's amazing about starshade is it was first conceived of in the 1960s imagine that and revisited every decade until now when we think we can actually build it and starshade is a giant specially shaped screen it is about there's different versions of it but think about 30 meters in diameter so you're blocking out the sun you're effectively blocking out the star yeah so that you can see the planet directly and starshade would have a spacecraft attached to it and it would fly in space far away from earth's gravity and it would have to formation fly with a space telescope so the idea is that starshade blocks out the starlight in a very careful way and it has to block that starlight out so that the planet that is 10 billion times fainter than the star that only the planet light goes to the telescope yeah so in formation meaning the telescope flies and um as you're giving a presentation on this but like it it would fly like and um this is extremely high precision endeavor yeah we had this analogy like asking a friend to hold up a dime five miles away yeah perfectly like at the perfect line of sight with you yeah and the shape of it is pretty cool i mean uh i don't know exactly what the physics of that like what the optics are that require that shape i can tell you it turns out that if you block out a star imagine blocking out a star with a circle circularly or a square shaped screen you wouldn't actually be blocking it because the star acts like a wave the starlight can act like a wave and it would actually bend around the edges of the screen and so instead of blocking out the light you're expecting to see nothing you would see ripples and the analogy that i love to give it's like throwing a pebble in a pond you get those ripples you get these concentric ripples and they go out and light would do something quite similar you'd actually see ripples of light and those ripples of light they're actually way brighter than the planet we'd be looking for so yeah so they would introduce this noise that's yeah noise and so this star shade it's like a mathematical solution to the problem of diffraction it's called and this is what the first person who thought about star shade in the 1960s worked out the mathematical shape or one solute one family of solutions and the idea is that when the star shade this very special shape like a giant flower with petals when it blocks out the light the light bends around the edges but interacts with itself in a way to give you a very very dark image it would be like throwing a pebble in a pond and instead of getting ripples the pond would be perfectly smooth like incredibly smooth to one part in 10 billion and all the waves would be on the outer edges far away from where you dropped that petal pebble and so what this camera would be able to uh this camera this telescope would be able to get uh get some signal from the planet then yes and it would be hard because the planet is so faint but with the star out of the way the glare of that bright bright bright star with that out of the way then it becomes a much more manageable task so how do we get that thing out there we're working with unlimited money okay working with unlimited money um we have some more engineering problems to solve but not too many more we've been burning down our so-called tall pool list and then we just what kind of list we call it tall techno uh technology tall pole it's the phrase where you have to figure out what are your hardest problems and then break those down to solve so the starshade one of the really hard problems was how did formation fly at tens of thousands of kilometers it's like wow that is insane and the team broke that down actually into a sensing problem because of the star shade how do you see the star shade precisely enough to to control it because if you're shining a flashlight you know the beam spreads out so the star shade has a beacon an led or a laser it's going to spread out so much by the time it gets to the telescope the problem wasn't how do you tell the star shade how to move around fast enough to stay in a straight line the problem was how do you how are you able to sense it well enough so problems like that were broken down and money that came from nasa to solve problems is put towards solving it so we're we've got through most of the hard problems right now another one was that star shade even though it's looking at a star light from our own sun could hit the edges of the star shade and bounce off into the telescope believe it or not and that would actually ruin it because we're trying to see this tiny tiny signal so then the question is how do you make a razor thin edge like those petal edges would be like have to be like a razor what materials can you so there's a series of problems like that so wow so there's a materials problem in there some of them and there's one so we almost finished solving all those problems and then it's just a matter of building one and testing it in a full scale size facility and then building the telescope it's just a matter of time to build everything and get it get it up for lunch so this is an easy close engineering yes this is an engineering project it's a real engineering project so i actually can tell you about two other projects that are not mine i like to call starshade mine because it was my project that i helped make it mainstream where that line is constantly shifting when i started when i got this leadership role on starshade i remember telling people about it and it was definitely not on the mainstream okay line it was on the giggle factor side of the line and people would just laugh like that's dead like you could never formation fly or they'd say why are you working on that that's just so not it's not this is so awesome there's a there's a few things you've done in your life and that's when i first saw starshine i was like what really and then like it sinks in i mean it's the same thing i felt with like elon musk or certain people who do crazy stuff like and then and they get they actually make it work i mean if you get started in formation flying to like together i mean how awesome is that if you actually make that happen even like from a robot i'm sorry from the robotics perspective even if it doesn't give us good data that's just like a cool thing to get out there i mean it's really exciting really cool so there's two other topics that aren't mine but i still love them one of them let's just talk about it briefly because it's not a probe but it's the idea to send a telescope very far away to 500 times the earth sun distance and this is way farther than the voyager spacecrafts are right now and to use our sun as a gravitational lens to use our sun to magnify something that's behind it it's got to sink in for a minute yeah exactly but i mean i don't know what the physics of that is like how to use the sun in astronomy and einstein thought about this initially we can use uh massive objects bend space and so light that should be traveling like straight it actually travels around the warped space and somehow you figure out a way to use that for magnification you have a way to use that for magnification that's right there are galaxies uh that are lens so-called gravitational lens by intervening galaxy clusters actually and there are microlensing events where stars get magnified as an unseen gravitational lens star passes in between us and that very distant star it's actually a real tool in astronomy yeah using gravitational lens to magnify because it bends more rays towards you than normally would you normally see and again we're trying to get more higher resolution images that are basically boiled down to light well it boils down to light and then you can maybe get more information about well in this case you would ask me let's say if this thing could get built it would take like something like they'd like to say 25 years to get from here to there 25 years and then it could send some information back to us and then you'd say so sarah how many pixels and i wouldn't say one or less than one i'd say you know it could be like 10 by 10 pixels it could be 100 pixels which would be awesome i mean it's still crazy that we can get a lot of information from that crazy right and it's crazy for a lot of other reasons because again you have to line up the sun and your target you'd only have one telescope per target because every star is behind the sun in a different way so it's a lot of complicated things but what about the second the second one it's called starshot you know starshot means like big dreams and it's an initiative by the breakthrough foundation and starshot is the concept to send thousands of little tiny spacecraft which they now call star chip so instead of star ship it's star chip and there's a little chip and the star chip so like sending like thousands of little turtles being born they're not all going to make it mm-hmm because they used to send lots of them and each of these star chips once they're launched into i guess low-earth orbit they will deploy a solar sail that's a few meters in diameter and they'd use it on earth we would have a bank of this one is still a bit on the other side of the line but we'd have a bank of telescopes with lasers there'd be like a gigawatt power and these lasers would momentarily shine upwards and accelerate they'd hit these sails they'd be like a power source for the sail and would accelerate the sails to travel at about a 20th the speed of light is that is that as crazy as it sounds well like like any good well like any good engineering project it has to be broken down into the crazy parts and the breakthrough initiative like to their huge credit is sponsoring you know getting over these actually they've listed initially they listed 19 challenges yes it's broken down to concrete things like one of them is well you have to buy the land and make sure the airspace is okay with you sending up that much power overhead another one is you have to have material on the sail where the lasers won't just uh vaporize it and well so there's a lot of a lot of issues but anyway these sails would be accelerated to 20th speed of light and their journey to the nearest star would now wouldn't would no longer be tens of thousands of years but could be 20 years okay 20. so it's not not as bad as tens of thousands yeah and this um these thousands or whatever however many make it they'll go by the nearest star system and snap a few snap some images and radio the information back to earth because they're traveling so fast they can't slow down but they'll zoom by take some photos send it back high res yeah but see just what i want you to pause on for a second is that just by making that a real concept and the money given won't make it happen but we'll but what it's done is it's planted the seed and it's shifted that line from what is crazy to what is a real project it's shifted it just ever so slightly enough i think to plant the seed that we have to find a way to somehow find a way to get there that is again to stay on that that is so powerful take a big crazy idea and break it down into smaller crazy ideas order it in a list and knock it out one at a time uh i don't know i've never heard anything more inspiring from an engineering perspective because that's how you solve the impossible things so you open your new book discussing rogue planet pso j318 i never said this out loud 0.522 so a rogue planet which is just this poetic beautiful vision of a planet that that as you right lurches across the galaxy like a rudderless ship wrapped in perpetual darkness it's surface swept by constant storms as black skies raining molten iron just like the vision of that the scary the the darkness the just how not pleasant it is for human life just the intensity of that metaphor i don't know and the reason you use that is to paint in a feeling of loneliness and despair and despair and um why maybe on the planet side why does it feel maybe it's just me why does it feel so profoundly lonely on that kind of planet like what uh like what i think it's because we all want to be a part of something a part of a family or a part of a community or a part of something and so our solar system and by the way i only it's sort of like a like when you treat yourself to like eating an entire tub of ice cream like i sometimes treat myself to imagine things like this and not just be so cut and dried but when you imagine that this plan is not because i don't want to give emotions to a planet per se but the planet's not part of anything it's somehow probably um it's just all on its own just kind of out there without that warm energy from its sun it's just all alone out there to me it was a little discovery that i actually feel pretty good at being part of the solar system it felt like we have a sun we have like a little family and it felt like it sucked for the rogue planet yeah to just floating about uh not floating of flying uh rudderless by the way how many rogue planets are there in your sun you don't know totally i mean there's some rogue planets that are just born on their own i know that sounds really weird to be how can you be born an orphan but they just are because most planets are born out of a disk of gas and dust around a star but some of these small planets are like totally failed stars they're so failed they're just small planets on their own but we think that there's probably honestly there's another path to a rogue planet that's one that's been kicked out of its star system by other planets like a game of billiard balls something just gets kicked out we actually think there's probably as many rogue planets as stars no flying out there um fundamentally alone so the book is uh as a memoir is about your life and it uh weaves both your fascination with planets outside the solar system and the path of your life and you lost your husband which is a kind of central part of the book that created a feeling of the rogue planet by the way what's the name of the book the name of the book is the smallest lights in the universe what's up with the title what's the meaning the title has a double meaning on the face of it it's the search for other earths earths are so dim compared to the big bright massive star beside them searching for the earth's is like searching for the smallest lights in the universe it has this other meaning too i really hope that you or the other people listening never get to the place where you're just you've fallen off the cliff into this horrible place of huge despair and once in a while you get a glimmer of a better life of some kind of hope and those are also the smallest lights in the universe well maybe we can tell the full story before we talk about the glimmer of hope um what did it feel like to first find out that your husband mike was sick it was incredibly frustrating like lots of us have had some kind of problem that the doctors completely ignore just that they kept blowing him off it's nothing are they paid to just say something i mean it's just insane i was just so angry and we finally got to a point where he was really sick he was like in bed not able to move basically and it turned out all the things they ignored and not done any tests he had like a 100 percent blockage in his intestine like a hundred percent like nothing could get out nothing could get in and it was pretty pretty shocking to even hear then that it could be nothing what was the progression of it in the context of the maybe the medical system the doctors i mean what did it feel like did you feel like a human being uh i felt like a child like the doctors were trying to water down the real diagnosis or treat us like we couldn't know the truth or they didn't know you know i felt mixed like it's not a good situation if you think the doctor either has no idea what he or she is doing or if the doctor is purposely let's just say lying to you to sugarcoat it like i didn't know which one of it was but i knew it was one of those what were what were the things he was suffering from well initially he just had a random stomachache i hate to say that out loud because i know a lot of people will have a random stomachache yeah but so he just had a bad stomach ache and then this is weird a few days later another bad stomachache kind of gets worse might go away for a few weeks might come back and at the time all i knew was my dad had had that same thing not the same identical system but he had these really weird pains and he ended up having the worst diagnosis one of the worst diagnosis you can get from a random stomachache is pancreatic cancer because the time the pancreas like you can't feel anything so by the time you feel pain it's too late it's spread already so i was just like beside myself i'm like this is like wow this guy he's a random stomachache all i know is another man i loved had a random stomachache and it didn't end well how did you deal with it emotionally psychologically intellectually as a scientist what was that like that that whole because it's not immediate it's a it's a long journey it's a long journey and you don't know where the diagnosis is going so anyone who's suffered from a major illness there's like always branches in the road so you know he had this intestinal blockage i can't imagine someone in their 40s having that and that be normal but the doctor is like it could be nothing could just cut it out you don't need most of your intestines it's a repeating pattern just cut that out it could be fine but it ended up not being fine and he was diagnosed as being terminally ill well it really changed my life in a huge way first of all i remember immediately one summer the summer when this happened i started asking everyone i knew i would ask you i know it's my job to put you on the spot i'd say you have one year to live or two or three what will you do differently about your life now lex you have one year to live what would you do i mean it's hard i don't know if you want to answer no no no i think about it a lot i mean that's a really good thing to meditate on we can talk about maybe how uh why you bring that up what if it is or not a heavy question but i get uh i i think about mortality a lot and for me it feels like a really good way to focus in on is what you're doing today the people you have around you the family you have is it uh does it bring you joy does it bring you fulfillment and basically uh for me of long ago tried to be ready to die any day so like today i you know i kind of woke up look if i was nervous about talking to um i've i really admire your work and the book is very good and super exciting topic uh but then you know there's this also feeling like if this is the last conversation i have in my life you know if i die today will this be let's be uh the right like am i glad today happened and it is and i am glad today uh happened so that that's the way and that's so unique i never got that answer from a single person the busyness of life there's goals there's dreams there's like planning plans very few people make it happen that's what i learned and so a lot of these people oh like you run out of time it's not so much time but i'd come back later and be little okay why don't you do that if that's what you would do if you're gonna die a year from now why don't you why don't you make it real simple things spend more time with family like why don't you do that and no one had an answer it turns out unless you usually unless you have you really do have a pressing end of life people don't do their bucket list or try to change their career and some people can't so we can't like for a lot of people they can't do anything about it and that's that's fine but the ones who can take action for some reason never do and that was uh one of the ways that mike's death or at the time his impending death really really affected me because you know for these sick people what i learned he had a bucket list and he was able to do some of the bucket lists it was awesome but he got sick pretty quickly so if you do only have a year to live it's ironic because you can't do you can't do the things you wanted to do because you get too sick too fast what were the bucket list things for you that you realize like what am i doing with my life that was the major cons of him after he died i didn't know like i i was just lost because when something that profound happens all the things i was doing um most of the things i was doing were just meaningless it was so tough to to find an answer for that and that's when i settled on i'm gonna devote the rest of my life to trying to find another earth and to find out to find that we're not alone what is that longing for connection with others um what's that about what do you think why is that so full of meaning i don't know why i mean i think it's how we're hardwired like one of my friends some time ago actually when my dad died he never heard someone say this before but he's like sarah you know why are we evolved to take death so harshly like what kind of society would we be if we just didn't care people died like that would be a very different type of world how would we as a species have got to where we are so i think that is tied hand in hand with why do we why do we seek connection it's just that we were talking about before that subconsciousness that we don't understand yeah coupled you know the other side the flip side of the coin of connection and love is a fear of loss it's like that was again i don't know that's what makes you appreciate the moment is that the thing ends yeah it's definitely a hard one the thing ends but and it's hard to not you you wouldn't want to limit like it's like my dog who i love so much i'll start to cry like i can't think about the end i know he'll age much faster than i will and someday it will end right but it's too sad to think of but should i not have got a dog right which i've not brought this sort of joy into my life because i know it won't be forever it's well there's a there's a philosopher ernest becker who wrote a book denial of death and just uh uh and warm with the cores and there's another book talks about terror management theory sheldon solomon i just talked to him a few weeks ago uh he's a brilliant philosopher a psychologist that their theory whatever you make of it is that um the fear of death is at the core of everything everything we do so like you're that you think you don't think about the mortality of your dog but you do and that's what makes the experience rich like there's this kind of like in the shadows lurks the the knowledge that this won't last forever and that makes every moment just special in some kind of uh weird way that it the moments are special for us humans i mean sorry to use romantic terms like love but what do you make what did you learn about love from from losing it from losing your husband well i learned to love the things i have more i learn to love the people that i have more and to not let the little things bother me as much what about the rediscovery or like the discovery of the little lights um uh in the darkness so you the book i think you brilliantly describe the dark parts of your journey uh but maybe can you talk about how you were able to rediscover the lights they came in many ways and the way like to think about it is like grief is an ocean you know with tiny islands of the little like like the little lights and eventually that ocean gets smaller and smaller and the islands like become continents with lakes so initially be like the children laughing one day or my colleagues at work who rallied around me and would take me away from my darkness to work on a project later on it turned out to be a group of women my age all widows all with children in my town and it would be even though it was a bit morose getting together um still very joyful at the same time what was the journey of rediscovering love like for you so refining i mean is there some by way of advice or insight about how to um how to rediscover the beauty of life of life it's a hard one i think you just have to stay open to being positive and just to get out there do you still think do you think about your immortality so you mentioned that that was a thing that you would meditate on as a question when it was right there in in front of you but do you still think about it i think i will after talking to you but no it's not really something i think about i mean i do think about the search for another earth and will will i get there will i be able to conclude my search and is there one like as time goes by you know that window to solve that problem gets smaller what would bring you again i apologize if this makes concrete the fact that life is finite but what um what would bring you joy if we discovered while you're still here will bring me joy finding another earth an earth like planet around a sun-like star knowing that there's at least one or more out there being able to see water that it has signs of water and being able to see some gases that don't belong so i know that the search will continue after i'm gone enough to fuel the next generation ah so just like opening the door and there's like this glimmer of what do you think it will take to realize that i mean we've talked about all these interesting projects starshade especially but is there something that you're particularly kind of uh hopeful about in the next 10 20 years that might give us that that exact glimmer of hope that there's earth like planets out there i have to i stand behind star shade in all cases so but there is this other kind of field that i that everyone is involved in because star shade is hard earths are hard but there are there's another category of planet star type that's easier and these are planets orbiting small red dwarf stars they're not earth-like at all think like earth cousin instead of earth twin but there's a chance that we might establish that some of those have water and signs of life on them that's nearer term than starshade and we're all working hard on that too let me ask uh by way of recommendations i think a lot of people are curious about this kind of stuff what three books technical or fiction or philosophical or anything really uh had an impact on your life and and or you would recommend besides of course your book there's one book i wish everyone could read i'm not sure if you've read it it's actually a children's book like a young adult book it's called the giver yes and it is the book that kids in school read now and i only sorry that that's not that's wow uh sorry that that caught me off guard uh so when i first came to this country i didn't speak much it's really what made me uh it had a profound impact on my life and i'm at a really important moment because they they give it to kids like i think middle school i think or maybe yes something like that i'm so surprised you've even heard of this book yeah so they give but like it's the value of giving the right book to a person at the right time uh i was as because it's very accessible do we want to share what the story is without spoiling it uh yeah you can without spoiling right it's follows this boy in this very utopic society that's like perfect it's been all clean cut and made perfect actually and as he kind of comes of age he starts realizing something's wrong with his world and so it's part of that question are we going to evolve this i mean this isn't what's there but it made me wonder you know are we evolving to a better place is there a day when we can eliminate you know poverty and hunger and crime and sickness in this book they pretty much have in the society that the boy's in and sort of follows him and he becomes a chosen one to be like a receiver the giver is the old wise man who retains some of the harshness of the outside world so that he can advise the people as the sort of boy comes of age and is chosen for the special role he finds the world isn't what he expects and i don't know about you but it was so profound for me because it jolts you out of reality it's like oh my god what am i doing here i'm just going with the flow with my society how do i think outside the box and the confines of my society which surely carries negative things with it that we don't realize today yeah and also in the flip side of that is if you do take a step outside the box on occasion uh what's the psychological burden of that like is that is is that your is that a step you want to take is that the journey you want to take what is that life like i don't know i felt like from the book you have to take it i found from the book i never thought like now that you're saying it i see what you're saying the burden is huge but i always feel like the answer is yes you absolutely want to know what's out what's outside but you can't do that if you're very it's hard to be objective about your own reality yeah i mean it's a very human instinct but uh it also the book kind of shows that it has an effect on you and this it's a really interesting question about our society taking a step out it's by lois lowry i think is how you pronounce it i really do hope everyone created and it is a young adult book but it's still it's incredibly i'm really glad i only read it because my kids got it for school i just thought okay well why don't i just see what this is about and i just wow yeah yeah i i think it's also the value of education i think i think i'm surprised you mentioned i've never really mentioned to anybody i'm sure a lot of people had some experience like me and maybe it's a generational thing though because like the book came out i think in the 90s so if you're older then like me that book didn't exist when we were in middle school so i just do think a lot of people won't have heard of it but it's an interesting question of like those books i mean i'm reminded often i suppose the same is true with other subjects but books are special at the early age like middle school maybe early high school this those can change like the direction of your life and also certainly teachers they can change completely the direction of life there's so many stories about teachers of mathematics teachers of physics of any kind of subjects basically changing the direction of a human's life that's like not to get on the uh the whole almost like a political thing but you know we uh we undervalue teachers uh it's a special it's a special position that they hold so true yeah well i do have two other books or two other things one is something i came across just a few days ago actually it's actually a film called picture a scientist and when you picture a scientist you probably don't picture the women and women of color in this film and it is a way to get outside your box i really think everyone interested in science even just peripherally should watch this because it is shocking and sobering at the same time and it talks about how well i think one of the messages across is you know we really are like i don't know if we're hardwired to just like people like ourselves but we're excluding a lot of people and therefore a lot of great ideas by not being able to think outside of how we're all stereotyping each other so it's it's it's hard to kind of convey that and you can just say oh yeah i want to be more diverse i want to be more open but it's a nearly impossible problem to solve and the movie really helps open people's eyes to it this book i put third because unlike the giver people may not want to read it it's not as relevant but when i was in my early 20s i went to this big this like 800 people large conference call us run by the wilderness canoe association in my hometown of toronto and there's a family friend there who i met and he said read this book it'll change your life and it actually changed my life and it was a book called sleeping island by an author pg downs who just coincidentally lived in this area lived in the boston area he was a teacher i think at a private school and every summer he would go to canada with a canoe often by himself and he wrote this book maybe in the 40s or 50s about a trip he took in the late 1930s and it was i was just shocked that even at that time although that was a long time ago there were large parts of canada that were untouched by white people and he went up there and interacted like with the natives he called the book it had a subtitle that was called there's something like journey in the barren lands and when you go up north in canada you pass the tree line just like on a mountain if you hike up a mountain you get so far north there aren't any trees and he wrote eloquently about the land and about being out there there weren't even any maps of the region like in that time and i just thought to myself wow like that you could just take the summer off and explore by canoe and go and see what's out there and it led to me just doing that that very thing of course it's different now but going out to where the road ends and putting the canoe in the water and just well we had to have a plan we didn't just explore but go down this river rivers with rapids and travel over lakes and portages and just really live so just really explore screw it that doesn't like it doesn't or just use from a topo map from a topographical map from the library and those things um there were scary elements about of it out of it but part of the excitement or the joy or the desire was to be scared like was to go out there and have live on the edge and persevere yeah and persevere yeah do you have an advice that you would give to a young person today that would like to help you maybe on the planetary science side discover exoplanets or maybe bigger picture just succeed in life i do have some advice just to succeed it's tough advice in a way but it is to find something that you love doing that you're also very good at in some ways the stars have to align because you've got to find that thing you're good at or the range of things and it actually has to overlap with something that actually you love doing every day so it's not a tedious job that's the best way to succeed what were the signals that in your own life were there to make you realize you're good at something that you're you're like what were you good at that made you uh pursue a phd and made you pursue the search i mean that was the one sentence version in my case it was a long slog and there were a lot of things i wasn't good at initially but so initially you know i was good at high school math i was good at high school science i loved astronomy and i realized those could all fit together like the day i realized you could be an astronomer for a job it has to be one of my top days of my life i didn't know that you could be that for a job yeah i was good at all those things and although my dad wanted me to do something more practical where he could be guaranteed i could support myself was another option but initially i wasn't that good at physics it was a slog to just get through school and grad school is a very very long time but ultimately when faced with a choice and i had the luxury of choosing knowing that i was good at something and also loved it it really carried me through now i asked some of the smartest people in the world the most ridiculous question uh we already talked about it a little bit but let me ask uh again why why are we here so uh i think you've uh raised this question when your presentations as like what one of the things that we kind of as humans long to to answer and the search for exoplanets is kind of part of that but what do you think is the meaning of it all of life i wish i had a good answer for you i think you're the first person ever who refused to answer the question it's not so much refusing i just yeah i mean i wish i had a better answer it's it's why we're here it's almost like the meaning is uh wishing there was a meaning that we wishing wishing we knew i love that that's a great way to that's a great way to say it so like i said uh the book is excellent i admired you work from afar for a while i'm i think you're one of the the great stars at mit and makes me proud to be part of the community so thank you so much for your work thank you for inspiring all of us thanks for talking today thank you so much lex thanks for listening to this conversation with sarah seeger and thank you to our sponsors public goods power dot and cash app click the links in the description to get a discount it's the best way to support this podcast if you enjoy this thing subscribe on youtube review the fire starters on apple podcast support it on patreon connect with me on twitter alex friedman spelled i'm not sure how just keep typing stuff in until you get to the guy with the tie in the thumbnail and now let me leave you with some words from carl sagan somewhere something incredible is waiting to be known thank you for listening and hope to see you next time you