Sara Seager: Search for Planets and Life Outside Our Solar System #116

Transcript

00:00:00 The following is a conversation with Sarah Seager, a planetary scientist at MIT known

00:00:06 for her work on the search for exoplanets, which are planets outside of our solar system.

00:00:12 She’s an author of two books on this fascinating topic, plus in a couple days, August 18th,

00:00:18 her new book, a memoir called The Smallest Lights in the Universe, is coming out.

00:00:23 I read it and I can recommend it highly, especially if you love space and are a bit of a romantic

00:00:29 like me.

00:00:30 It’s beautifully written.

00:00:32 She weaves the stories of the tragedies and the triumphs of her life with the stories

00:00:36 of her love for and research on exoplanets, which represent our hope to find life out

00:00:43 there in the universe.

00:00:45 Quick summary of the ads.

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00:00:58 Just a quick side note.

00:00:59 Let me say that extraterrestrial life, aliens, I think represent our civilization longing

00:01:06 to make contact with the unknown, with others like us, or maybe others that are very different

00:01:12 from us, entities that might reveal something profound about why we’re here.

00:01:18 The possibility of this is both exciting and, at least to me, terrifying, which is exactly

00:01:25 where we humans do our best work.

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00:05:27 And now here’s my conversation with Sarah Seeger.

00:05:32 When did you first fall in love with the stars?

00:05:34 I think I’ve always loved the stars.

00:05:37 One of my first memory is of the moon.

00:05:39 I remember watching the moon and I was in the car with my dad who my parents were divorced

00:05:44 and he was driving me and my siblings to his house for the weekend and the moon was just

00:05:47 following me.

00:05:49 Just had no idea why that was.

00:05:51 So like looking up at the sky and there’s this glowing thing, how do you make sense

00:05:55 of the moon at that age?

00:05:57 Like age five.

00:05:58 There’s just no way you can.

00:05:59 I think it’s one of the great things about being a kid is just that curiosity that all

00:06:03 kids have.

00:06:04 You know, I was thinking because there’s these almost out there ideas of that our earth is

00:06:11 flat, floating about on the internet.

00:06:14 And it made me think, you know, when did I first realize that the earth is like this

00:06:21 ball that’s flying through empty space?

00:06:25 I mean, it’s terrifying.

00:06:27 It’s awe inspiring.

00:06:28 I don’t know how to make sense of it.

00:06:31 It’s hard because we live in our frame of reference here on this planet.

00:06:34 It’s nearly impossible.

00:06:35 None of us are lucky to go to see the curvature of earth.

00:06:38 I mean, do you remember when you realized, understood like the physics, like the layout

00:06:43 of the solar system?

00:06:45 Was it like, did you first have to take physics to really, like high school physics to really

00:06:51 take that in?

00:06:52 I think it’s hard to say.

00:06:53 I had this book when I was a child.

00:06:55 It was in French.

00:06:56 I grew up in Canada, where French is supposedly taught to all of us English speaking Canadians.

00:07:01 And it was this book in French was about the solar system, and I just love flipping through

00:07:05 it.

00:07:06 It’s hard to say how much, you know, you or I understand when we’re kids, but it was

00:07:10 really great book.

00:07:11 What about the stars?

00:07:12 When did you first learn about the stars?

00:07:14 Like I do have this very incredible distinctive memory.

00:07:17 And again, it had to do with my dad.

00:07:19 He took us camping.

00:07:20 Now, my dad was from the UK, and he was the type who you’d find wearing a tie on weekends.

00:07:26 So camping was not in his sphere, his comfort zone.

00:07:29 We had a babysitter.

00:07:31 Every summer we had a babysitter, and one summer we had Tom.

00:07:34 He was barely older than we were.

00:07:36 He was 14.

00:07:37 My brother was 12.

00:07:38 I would have been 11 or 10 maybe.

00:07:40 And we went camping because Tom said camping is the thing.

00:07:42 We should try it.

00:07:43 And I just remember I didn’t aim to see the stars, but I walked out of my tent in the

00:07:48 middle of the night, and I looked up, and wow, so many stars.

00:07:55 The dark night sky and all those stars just screaming at me.

00:07:59 I just couldn’t believe that.

00:08:00 Honestly, my first thought was, this is so incredible, mind blowing.

00:08:04 Why wouldn’t anyone have told me this existed?

00:08:07 Can anyone else see this?

00:08:08 Have you had an experience like that with anything?

00:08:12 Yeah.

00:08:13 I’ve had that.

00:08:14 I mean, I don’t know if maybe you can tell me if it’s the same.

00:08:17 I’ve had that with robots.

00:08:20 There’s a few robots I’ve met where I just fell in love with this.

00:08:23 Is anyone else seeing this?

00:08:25 Is anyone else seeing that here in a robot is our ability to engineer some intelligent

00:08:34 beings, intelligent beings that we could love, that could love us, that we can interact with

00:08:39 in some rich ways that we haven’t yet discovered?

00:08:44 Almost like when you get a puppy, instead of a dog, and there’s this immediate bond

00:08:49 and love, and on top of that, ability to engineer it, I had to just pause and hold myself.

00:08:58 I imagine, I don’t have kids, I imagine there’s a magic to that as well, where it’s a totally

00:09:03 new experience.

00:09:04 It’s like, what?

00:09:05 Well, yeah, the stars though, unlike kids or the puppy, it’s only a good thing.

00:09:13 So you felt, you weren’t terrified?

00:09:15 Like to me, when I look at the stars, it’s almost paralyzingly scary how little we know

00:09:23 about the universe, how alone we are.

00:09:26 I mean, somehow it feels alone.

00:09:28 I’m not sure if it’s just a matter of perspective, but it feels like, wow, there’s billions

00:09:34 of them out there and we know nothing about them.

00:09:39 And then also immediately to me, somehow mortality comes into it.

00:09:42 I mean, how did that make you feel at that time?

00:09:45 I think as a child without articulating it, I felt that same way.

00:09:48 Just like, wow, this is terrifying.

00:09:50 What’s out there?

00:09:51 Like, what is this?

00:09:52 What does it mean about us here?

00:09:55 You’re a scientist, an exo world class scientist, planetary scientist, astronomer.

00:10:02 Now I’m a bit of an idiot who likes to ask silly questions.

00:10:06 So some questions are a little bit in the realm of speculation, almost philosophical

00:10:12 because we know so little and one of the awesome things about your work is you’ve actually

00:10:17 put data and real science behind some of the biggest questions that we’re all curious

00:10:20 about.

00:10:21 But nevertheless, many of the questions might be a little bit speculative.

00:10:25 So on that topic, just in your sense, do you think we’re alone in the universe, human

00:10:33 beings?

00:10:34 Do you think there’s life out there?

00:10:36 Well, Lex, the funny thing is, is that as a scientist, I so don’t even want to answer

00:10:40 that.

00:10:41 I will answer it though, but I just love to say, yeah, we naturally resist that because

00:10:46 we want numbers and hard facts and not speculation.

00:10:49 But I do love that question.

00:10:51 It’s a great question and it’s one we all wonder about, but I have to give you the scientist

00:10:55 answer first, which is we’ll have the capability to answer that question soon, even starting

00:11:01 soon.

00:11:02 How do you define soon?

00:11:03 How do I define soon?

00:11:05 So much happened in the last hundred years.

00:11:07 Right, right.

00:11:08 And there’s a difference, right, if it’s 10 years or 20 years or a hundred years.

00:11:11 Yeah, there’s a difference in that.

00:11:14 Well, soon could be a decade or two decades.

00:11:18 Journalists usually don’t like that or the people want like tomorrow, they want the news.

00:11:23 But what it’s going to take is telescopes, space telescopes, or very sophisticated ground

00:11:28 or space telescopes to let us study the atmospheres of other planets far away and to look what’s

00:11:35 in the atmospheres and to look for water, which is needed for life as we know it, to

00:11:38 look for gases that don’t belong that we might attribute to life.

00:11:42 So we have to do some really nitty gritty astronomy.

00:11:45 So the promising way to answer this question scientifically is to look for hints of life.

00:11:51 That’s where like many of your ideas come in of what kind of hints might we actually

00:11:55 see about this life.

00:11:57 Right, right.

00:11:58 That’s exactly what we need to do.

00:11:59 And I like the word you chose, hint, because it’s going to be a hint.

00:12:02 It’s not going to be a 100% yay, we found it.

00:12:05 And then it will take future generations to do more careful work to hopefully even find

00:12:12 a way to send a probe to these distant exoplanets and to really figure this out for us.

00:12:17 I mean, we’ll talk about the details.

00:12:19 Those are fun, but like the back to the speculation, the zoomed out big picture is, yes, I believe

00:12:26 absolutely there is life out there somewhere.

00:12:30 Because the vastness of the universe is incredible.

00:12:33 It’s so breathtaking.

00:12:35 When we look at the night sky, if you can go to that dark sky, you can see many, many

00:12:40 hundred or even if you have good eyesight and you’re somewhere very dark, you could

00:12:43 see thousands of stars.

00:12:44 But in our galaxy, we have hundreds of billions of stars and our universe has hundreds of

00:12:51 billions of galaxies.

00:12:53 So think about all those stars out there.

00:12:57 And even if planets are rare, even if life is rare, just because the number of stars

00:13:02 is so huge, things have to come together somewhere, someplace in our universe.

00:13:06 Yeah.

00:13:07 So amazing to think that somebody might be looking up on another planet in a distant

00:13:14 galaxy.

00:13:15 I have to interrupt your reverie and get back to, in our lifetime at least, the short term.

00:13:22 We only have the nearest stars to look at.

00:13:24 It’s true that there are so many stars, so many hosts for planets that might have life.

00:13:29 But in the practical question of will we find it, it has to be a star quite close to Earth,

00:13:36 like a few light years, tens of light years, maybe hundreds of light years.

00:13:40 And by the way, you’ve introduced me to a tool of Eyes on Exoplanets, I think that NASA

00:13:46 has put together.

00:13:47 Eyes on Exoplanets.

00:13:48 It’s a great software.

00:13:49 You can download it.

00:13:50 It’s so cool.

00:13:51 But anyway, can you give a sense of who our neighbors are?

00:13:56 You said hundreds of light years.

00:14:00 How many stars are close by?

00:14:04 What’s our neighborhood like?

00:14:05 Are we talking about five, 10 stars that we might actually have a chance to zoom in on?

00:14:12 I’m talking about maybe a dozen or two dozen stars.

00:14:16 And those with planets that look suitable for us to follow up in detail.

00:14:22 For life.

00:14:23 Right.

00:14:24 But one thing that’s really exciting in this field is that the very nearest star to Earth

00:14:29 called Proxima Centauri, it’s part of the Alpha Centauri star system.

00:14:34 Cool name, by the way.

00:14:35 Yeah, Proxima.

00:14:36 Whoever names them.

00:14:37 Nearby.

00:14:38 Okay, but it sounds cooler than Proxima.

00:14:40 Proxima Centauri appears to have a planet around it.

00:14:44 It’s about an Earth mass planet in the so called habitable zone or the Goldilocks zone

00:14:49 of the host star.

00:14:50 So think about how incredible that is.

00:14:52 Like out of all the stars out there, even the very nearest star has planets and has

00:14:56 a planet of huge interest to us.

00:14:58 Yeah.

00:14:59 Okay.

00:15:00 So can we talk about that planet?

00:15:04 What does it mean to be maybe possibly habitable?

00:15:12 How does size come into play?

00:15:14 How does you know what we know about gases and what kind of things are necessary for

00:15:21 life?

00:15:22 You know, what are the factors that you make you think that it’s habitable?

00:15:26 And by the way, I mean, maybe one way to talk about that is people know about the Drake

00:15:31 equation, which is a very high level, almost framework to think about what is the probability

00:15:39 that, correct me if I’m wrong, that there’s life out there and intelligent life, I think.

00:15:46 I don’t know.

00:15:47 But then you have a equation named after you now, which I think nicely focuses in on the

00:15:54 more achievable and interesting part of that question, which is on whether there is habitable

00:16:01 planets out there or how many, I guess.

00:16:04 Right, right.

00:16:05 So the funny thing is, was one time I met Frank Drake and I asked if he minded if I

00:16:11 took his equation and kind of revamped it for this new field of exoplanet astronomy.

00:16:17 He was totally cool with it.

00:16:18 He’s totally cool.

00:16:19 He got total approval.

00:16:20 Well, maybe.

00:16:21 Okay.

00:16:22 So sorry.

00:16:23 I’m not sure if he’d actually read the stuff about my equation, but he was cool with it.

00:16:26 He was cool.

00:16:27 He was cool.

00:16:28 Okay.

00:16:29 So I just said like 15 different things, but maybe can you tell from your perspective,

00:16:33 what is the Drake equation and what is, sorry, the Seager equation?

00:16:37 Sure.

00:16:38 Well, the Drake equation, as you said, it’s a framework.

00:16:41 It’s a description of the number of civilizations out there of intelligent beings that are able

00:16:48 to communicate with us by radio waves.

00:16:53 So if you think of the movie Contact, you’ve seen Contact, right?

00:16:58 We’re listening in, actually.

00:16:59 It’s an active field of research, listening to other stars at radio wavelengths, hoping

00:17:03 that some intelligent civilizations are sending us a message.

00:17:07 And the Drake equation came like at the start of that whole field to put the factors down

00:17:12 on paper to sort of illustrate what is involved to kind of estimating.

00:17:18 And there’s no real estimate or prediction of how many civilizations are out there, but

00:17:21 it’s a way to frame the question and show you each term that’s involved.

00:17:25 So I took the Drake equation and I called it a revised Drake equation and I recast it

00:17:32 for the search for planets by more traditional astronomy means.

00:17:37 We’re looking at stars, looking for planets, looking for rocky planets, looking for planets

00:17:42 that are the right temperature for life, looking for planets that might have life that outputs

00:17:49 gases that we might detect in the future.

00:17:52 It’s the same spirit of the Drake equation.

00:17:53 It’s not going to give us any magic numbers.

00:17:55 So I’m going to say, hey, here’s exactly what’s out there.

00:17:58 It’s meant to kind of guide, guide of where we’re going.

00:18:01 So the Drake equation did, I mean the initial equation proposed actual numbers for those

00:18:06 variables, right?

00:18:07 Oh yes.

00:18:08 The equation proposed numbers and you can still plug your own numbers in.

00:18:12 And there’s this really cute website that lets you for both the Drake and my revised

00:18:15 equation plug in some numbers and see what you got.

00:18:19 So yeah.

00:18:20 Okay.

00:18:21 So what are, I mean, what are the variables, but maybe also what are like the critical

00:18:24 variables?

00:18:26 So in my equation, I set out to what are the numbers of inhabited planets that show signs

00:18:33 of life by way of gases in the atmosphere that can be attributed to life.

00:18:37 I could just walk through the terms as far as I’m aware.

00:18:39 So the first thing I say is what are the number of stars available?

00:18:43 And it’s not that those trillions and trillions of stars everywhere.

00:18:47 It’s what are available to like a specific search.

00:18:51 And so for example, the MIT led NASA mission TESS is surveying the sky, looking for all

00:18:57 kinds of planets, but it can also, it also has stars.

00:19:01 It has about 30,000 red dwarf stars.

00:19:04 So we just take a number of stars that a given survey can access.

00:19:08 So that’s what the number of stars is.

00:19:11 Then I wanted to know what kind of stars are quiet.

00:19:16 I called it fraction of those stars that is quiet.

00:19:19 In the case of TESS, the way it’s looking for planets is planets that transit the star.

00:19:23 They go in front of the star as seen from the telescope, but it turns out that some

00:19:27 stars are very active, they’re variable and they brighten and dim with time and that interferes

00:19:32 with our observation.

00:19:33 I apologize to interrupt.

00:19:35 So it’s a transiting planet.

00:19:37 So you’re really looking for a black blob, essentially that blocks the light.

00:19:42 We’re looking for a black blob that blocks the light and then trying to say something

00:19:45 about the size of the planet from the frequency of that black blobs appearance and the size

00:19:51 of that black blob, that kind of thing.

00:19:53 Yeah.

00:19:54 But let’s just say that out of all the stars there are accessible to whatever telescope,

00:19:58 some of them are just bad for whatever reason.

00:20:00 You’re not going to be able to find planets around them.

00:20:02 So I need to know the fraction of those that are, that are good.

00:20:05 So again, we have the number of stars, the fraction of them that we can actually find

00:20:09 planets around.

00:20:10 And by the way, is our sun one such, is our sun quiet?

00:20:16 Our sun is quiet.

00:20:17 Okay.

00:20:18 So I have actually two terms.

00:20:20 One describes how quiet they are and one is if we can find a planet around that star.

00:20:25 These transiting planets, for example, not all planets transit because the planet would

00:20:30 have to be orbiting that star in this kind of plane as viewed from you.

00:20:36 But if a star is, for example, orbiting in the plane of the sky, it will never transit.

00:20:40 It will never go in front of the star.

00:20:43 So in that case, we have to have a fraction that takes into account of that kind of geometric

00:20:47 factor.

00:20:48 And hopefully, I mean, you can assume that it’s uniformly distributed, hopefully.

00:20:52 Yes, we can assume and there’s evidence that it’s uniformly distributed, yes.

00:20:56 So then the next, so all of these factors so far, number of stars accessible to whatever

00:21:01 telescope you’re thinking about, how many stars are quiet, fraction of stars that are

00:21:06 quiet, fraction that are observable, in this case for the geometric factor, those are all

00:21:10 things we can measure.

00:21:11 And there’s one more term in the secret equation we can measure.

00:21:14 I call it fraction of planets in the habitable zone.

00:21:18 Because believe it or not, we have a handle on that for a certain set of stars.

00:21:23 We know from our, the Kepler Space Telescope that operated for a number of years, we have

00:21:28 estimates for how many planets are in the so called habitable zone of the host star

00:21:31 for a certain type of star.

00:21:33 So all those we have measurable.

00:21:34 And then like the Drake equation itself, there are some terms we can not measure.

00:21:39 And those ones, I call them FL, fraction of all those planets that have life on them.

00:21:46 Because we don’t know what that is.

00:21:47 And FS, I called for spectroscopy, the fraction that have, we can use our telescope and instrument

00:21:55 tools to look for light.

00:21:58 The FS was the ones that, the planets that have life that actually gives off a gas, a

00:22:03 useful gas that might accumulate in the atmosphere, so we could eventually observe it.

00:22:10 How do the FL and FS interplay?

00:22:12 So these are separate terms?

00:22:14 Separate terms.

00:22:15 And so?

00:22:16 So for example, you could imagine, so for example, you could imagine life, like us humans,

00:22:23 we breathe out carbon dioxide.

00:22:26 And our planet Earth, we already have a lot of carbon dioxide on it.

00:22:29 Well, we have hundreds of parts per million, but it has a really strong signal.

00:22:33 So us humans breathing out carbon dioxide, it’s not helpful for any intelligent beings

00:22:37 that are looking back at Earth, because there’s already a lot of, there’s already enough carbon

00:22:41 dioxide, we’re not adding to it.

00:22:43 So if there is life on a planet, and it’s outputting a boring gas that’s not helpful

00:22:47 for us to uniquely identify as being made by life versus just being there anyway, then

00:22:54 it’s not helpful.

00:22:55 So I separated those two terms out.

00:22:57 Soon I think we’ll have evidence that planets that can support life at least are common.

00:23:04 So okay, this is such an awesome topic, I have a million questions.

00:23:11 What okay, I know this is a little bit of speculation, but what’s your sense about that,

00:23:16 I think FS, which is like, that life would produce interesting gases that would be able

00:23:23 to detect, like, is there, one, is there scientific evidence and, and second, is there some intuition

00:23:30 around life producing gases with detectable hints in terms of chemistry?

00:23:36 So interestingly enough, that entire question relates to, I’m going to say almost my life’s

00:23:43 work, the work I’m doing now and the work I’m doing for the next 20 years, and I wish

00:23:46 I could give you a concrete number, like 1%, like on the worst days, it’s 1%, let’s say

00:23:51 in my mind.

00:23:52 You know, in the best days, it’s like 80%.

00:23:54 And I could actually go into a lot of detail here, but I’ll just give you the simplest

00:23:58 things.

00:23:59 So first of all, we make an assumption that like us, and our life here on Earth, life

00:24:05 uses chemistry.

00:24:07 So we use chemistry because we eat food, we breathe air, and we have metabolism that to

00:24:13 break down food to get energy to store energy, and then ultimately to use it.

00:24:18 And all life here has some kind of byproduct in doing all that, some kind of waste product

00:24:22 that goes into the atmosphere.

00:24:24 So I like to think that life everywhere uses chemistry.

00:24:28 Some people have imagined, like, let’s imagine like a windmill, like mechanical energy, just

00:24:34 getting energy and using it without storing it.

00:24:37 And if there was life like that, it might not need to output a gas.

00:24:40 So we make this basic assumption of chemistry, that’s the first thing.

00:24:44 The second more complicated thing that I and my team work on is what happens to the gas

00:24:47 once it is produced by life, it goes into the atmosphere.

00:24:51 And a lot of gas is just destroyed immediately, actually, by ultraviolet radiation or by oxygen.

00:24:59 Oxygen is incredibly destructive to a lot of gases.

00:25:03 So the gas can be produced by life, but it could be just completely destroyed by its

00:25:07 environment.

00:25:08 I guess we should pause on that, that you mentioned your life’s work.

00:25:13 This is just the beautiful idea that it’s kind of paralyzing when you look out there

00:25:19 and you wonder, is there a life out there?

00:25:22 It’s the first paralyzing, actually, before I encountered your work, I feel like an idiot.

00:25:27 But you know, it feels like there’s no tool to answer that question.

00:25:32 And then what you kind of provided is this cool idea that it might be possible to answer

00:25:40 that by looking at the gases.

00:25:41 I mean, that’s a really interesting, that’s a beautiful idea.

00:25:45 And yeah, so we could just pause on like, that’s a powerful tool, I think, to build

00:25:55 the intuition around, because I was totally clueless about it.

00:25:57 And that was kind of exciting.

00:25:59 I mean, I’m sure there’s folks probably early on in your life who were very skeptical about

00:26:05 this notion.

00:26:06 Well, maybe I’m not sure, but generally you would want to be skeptical, it’s like, well,

00:26:13 all these kinds of other things could generate gases, you know, all those kinds of things.

00:26:17 Oh, that’s so true.

00:26:18 And that’s a big part of this growing field is how to make sure that this gas isn’t produced

00:26:23 by another effect.

00:26:24 But I do want to, you know, again, pausing on that and going back a bit.

00:26:29 It’s incredible to think, but like, at least almost 100 years ago, there’s a record of

00:26:33 someone talking about the idea of a gas being an indicator of life elsewhere.

00:26:38 That idea was floating about somewhere.

00:26:40 Yes, it was totally floating about.

00:26:42 And it comes down to oxygen, which on our planet fills our atmosphere to 20% by volume.

00:26:48 And you know, we rely on oxygen to breathe.

00:26:50 You know, when you hear about the people in Mount Everest running out of air, they’re

00:26:54 really running out of oxygen, well, they’re running out of oxygen because the air is getting

00:26:57 thinner as they climb up the mountain.

00:27:01 But without plants and bacteria, there’s bacteria that also photosynthesizes and produces oxygen

00:27:08 as a waste product.

00:27:09 Without those, we would have virtually no oxygen.

00:27:13 Our atmosphere would be devoid of oxygen.

00:27:15 So yeah, if you were to analyze Earth, is oxygen the strong indicator here?

00:27:21 Oxygen is a huge indicator.

00:27:22 And that’s what we’re hoping, that there is an intelligent civilization not too far from

00:27:26 here around a planet orbiting a nearby star with the kind of telescopes we’re trying to

00:27:31 build.

00:27:32 And they’re looking back at our sun and they’ve seen our Earth and they see oxygen.

00:27:36 And they probably won’t be like 100.0% sure that there’s life making it.

00:27:41 But if they go through all the possible scenarios, they’ll be left with a pretty strong hint

00:27:45 that there’s life here.

00:27:46 Yeah.

00:27:47 Okay, but how do you detect that type of gases that are on the planet from a distance?

00:27:55 And that’s going back to that, that’s what people were skeptical about.

00:28:00 When I first started working on exoplanets a long time ago, people didn’t believe we

00:28:04 would ever, ever, ever study an exoplanet atmosphere of any kind.

00:28:09 And now dozens of them are studied.

00:28:11 There’s a whole field of people, hundreds of people working on exoplanet atmospheres

00:28:14 actually.

00:28:15 Wow.

00:28:16 But first there was a point where people didn’t even know there was exoplanets, right?

00:28:20 When was the first exoplanet detected?

00:28:23 The first exoplanet around a sun like star anyway was detected in the mid 1990s.

00:28:27 That was a big deal.

00:28:29 Kind of vaguely remember that.

00:28:30 Well, at the time it was a big deal, but it was also incredibly controversial.

00:28:34 Because in exoplanets, we only had one example of a planetary system, our own solar system.

00:28:41 And in our solar system, Jupiter, our big massive planet, is really far from our star.

00:28:48 And this first exoplanet around a sun like star was incredibly close to its star, so

00:28:53 close that people just couldn’t believe it was a planet actually.

00:28:56 So maybe zoom out, what the heck is an exoplanet?

00:29:00 An exoplanet is our name, like is the name that we call a planet orbiting a star other

00:29:05 than our sun.

00:29:07 Right.

00:29:08 Extrasolar, I guess is another.

00:29:09 You can call it extrasolar.

00:29:10 Okay.

00:29:11 Exoplanet is simpler.

00:29:12 But I think it’s worth pausing to remember that each one of those stars out there in

00:29:17 our night sky is a sun.

00:29:18 And you know, our sun has planets, Mercury, Venus, Earth, Mars, etc.

00:29:23 And so for a long time, people have wondered, do those other stars or other suns have planets?

00:29:29 And they do.

00:29:30 And it appears that nearly every star has a planet, has a planet we call exoplanet.

00:29:34 And there are thousands of known exoplanets already.

00:29:37 So there’s already, yeah, like, there’s so many things about space that it’s hard to

00:29:42 put into one’s brain, because it starts filling it with awe.

00:29:47 So yeah, if you visualize the fact that the stars that we see in the sky aren’t just stars,

00:29:54 they’re like, they’re suns.

00:29:57 And they very likely, as you’re saying, would have planets around them.

00:30:03 There’s all these planets roaming about in this like, dimly lit darkness, with potentially

00:30:11 life.

00:30:12 I mean, it’s just mind blowing.

00:30:14 But maybe can you give a brief, like, history of discovering all the exoplanets?

00:30:23 So there’s no exoplanets in the 90s.

00:30:26 And then there’s a lot of exoplanets now.

00:30:28 So how did that come about?

00:30:29 So many planets.

00:30:31 How did it come about?

00:30:32 Well, maybe another way to ask is, what is the methodology that was used to discover

00:30:37 them?

00:30:38 I can say that.

00:30:39 But I’d like to just say something else first where, so exoplanets, you know, the line

00:30:43 between what is considered completely crazy.

00:30:47 And what is considered mainstream research, legit, is constantly shifting.

00:30:51 This is awesome.

00:30:52 Yeah.

00:30:53 So before, when I started on exoplanets, it was still sketchy.

00:30:56 Like, it wasn’t considered a career, a thing, a place where you should be investing.

00:31:01 And right now, now, today, it’s so many people are working in this field, a good, I don’t

00:31:06 know, at least 1000, probably more.

00:31:08 I don’t know if that sounds like a lot to you, but it’s a lot.

00:31:10 No, it’s a legitimate field of inquiry.

00:31:13 Yeah.

00:31:14 Legitimate field of inquiry.

00:31:15 And what’s helped us is everything that’s helped everyone else.

00:31:18 It’s software, it’s computers, it’s hardware.

00:31:21 It’s like our phones.

00:31:22 You have a fantastic detector in there.

00:31:23 Like, they didn’t always have that.

00:31:25 I don’t know if you remember the so called olden days.

00:31:28 We didn’t have digital cameras.

00:31:29 We had film.

00:31:30 You take a film camera, you send the film away, and eventually it comes back, and then

00:31:33 you see your pictures.

00:31:34 And they could all be horrible.

00:31:35 Yeah.

00:31:36 So yeah, I mean, digital.

00:31:37 It just changed everything.

00:31:38 Data changed everything.

00:31:39 Yeah, and so one thing that really helped exoplanets were detectors that were very sensitive.

00:31:45 Because when we’re looking for the transiting planets, what we’re doing is we’re monitoring

00:31:51 a star’s brightness as a function of time.

00:31:53 It’s like click, taking a picture of the stars every few seconds or minutes.

00:31:58 And we’re measuring the brightness of a star, like every frame.

00:32:02 And we’re looking for a drop in brightness that’s characteristic of a planet going in

00:32:06 front of the star, and then finishing its so called transit.

00:32:11 And to make that measurement, we have to have precise detectors.

00:32:15 And the detectors that are making the measurement, can you do it from Earth?

00:32:22 Are they floating about in space, like what kind of telescope?

00:32:25 So on the ground, people are using telescopes, small telescopes that are almost just like

00:32:30 a glorified telephoto lens.

00:32:32 And they’re looking at big swaths of the sky.

00:32:35 And from the ground, people can find giant planets like the size of Jupiter.

00:32:38 So it’s about 10 to 12 times the size of Earth.

00:32:41 We can find big planets, because we can reach about 1% precision.

00:32:46 So not sure how technical you want to get.

00:32:48 Well, how many pixels are we talking about?

00:32:53 You mentioned phones, there’s a bunch of megapixels, I think.

00:32:56 So for exoplanets, you want to think about it as like a pixel or less than a pixel, we’re

00:33:01 not getting any information.

00:33:03 But to be more technical, our telescope spreads the light out over many pixels, but we’re

00:33:08 not getting information.

00:33:09 We’re not tiling the planet with pixels.

00:33:12 It’s just like a point of light, or in most cases, we don’t even see the planet itself,

00:33:16 just the planet’s effect on the star.

00:33:17 But another thing that really helped was computers, because transiting planets are actually quite

00:33:22 rare.

00:33:23 I mean, they don’t all go in front of their star.

00:33:25 And so to find transiting planets, we look at a big part of the sky at once, or we look

00:33:29 at tens of thousands or hundreds of thousands, or even in some cases, millions of stars at

00:33:34 one time.

00:33:35 And so you’re not going to do this by hand, going through a million stars, counting up

00:33:39 the brightness.

00:33:40 So we have computer software and computer code that does the job for us and counts the

00:33:47 brightness and looks for a signal that could be due to a transiting planet.

00:33:51 And I just finished a job called Deputy Science Director for the MIT led NASA mission test.

00:33:59 And it was my purview to make sure that we got the planet candidates, the transiting

00:34:05 light curves, out to the community so people could follow them up and figure out if they’re

00:34:10 actual planets or false positives.

00:34:13 So publish the data so that people could just, all the data scientists out there could crunch

00:34:19 and see if they can discover something.

00:34:21 They can discover something.

00:34:22 And in fact, the NASA policy for this mission is that all the data becomes public as soon

00:34:26 as possible.

00:34:28 It’s not as easy as it sounds, though, to download the data and look for planets.

00:34:33 But there is a group called PlanetHunters.org, and they take the data and they actually crowdsource

00:34:38 it out to people to look for planets.

00:34:40 Yeah.

00:34:41 And they often find signals that our computers and our team missed.

00:34:44 So we mentioned exoplanets.

00:34:46 What about Earth like, or I don’t know what the right distinction is, is it habitable

00:34:51 or is it Earth like planets, but what are those different categories and how can we

00:34:55 tell the difference and detect each?

00:34:57 Right, right.

00:34:58 So we’re not at Earth like planets yet.

00:35:01 All the planets we’re finding are so different from what we have in our solar system.

00:35:06 They’re just easier planets to find, but like…

00:35:08 In which way?

00:35:09 For example, there could be a Jupiter sized planet where an Earth should be.

00:35:14 We find planets that are the same size as Earth, but are orbiting way closer to their

00:35:20 star than Mercury is to our sun.

00:35:24 They’re so close that, because close to a star means they also orbit faster.

00:35:29 And some of these hot super Earths we call them, their year, their time to go around

00:35:33 their star is less than a day.

00:35:36 And they’re heated so much by their star, they’re heated so much by the star.

00:35:40 We think the surface is hot enough to melt rock.

00:35:42 So instead of running out by the bay or the river, you’ll have like liquid lava.

00:35:47 There’ll be liquid lava lakes on these planets, we think.

00:35:51 And life can’t survive.

00:35:53 Way too hot.

00:35:54 The molecules needed for life just wouldn’t be able to survive those temperatures.

00:35:59 We have some other planets.

00:36:00 One of the most mysterious things out there, factoid, if you will, is that the most common

00:36:07 type of planet we know about so far is a planet that’s in between Earth and Neptune size.

00:36:12 It’s two to three times the size of Earth.

00:36:15 And we have no solar system counterpart of that planet.

00:36:19 That is like going outside to the forest and finding some kind of creature or animal that

00:36:24 just no one has ever seen before and then discovering that is the most common thing

00:36:27 out there.

00:36:29 And so we’re not even sure what they are.

00:36:30 We have a lot of thoughts as to the different types of planet it could be, but people don’t

00:36:34 really know.

00:36:35 I mean, what are your thoughts about what it could be?

00:36:37 Well, one thought, and this is more when we want to be rather than might be, is that these

00:36:43 so called mini Neptunes, we call them, that they are water worlds, that they could be

00:36:48 scaled up versions of Jupiter’s icy moons, such that they are planets that are made of

00:36:54 more than half of water by mass.

00:36:57 And what’s the connection between water and life and the possibility of seeing that from

00:37:02 a gas perspective?

00:37:03 Okay, so all life on Earth needs liquid water.

00:37:07 And so there’s been this idea in astronomy or astrobiology for a long time called follow

00:37:12 the water, find water, that will give you a chance of finding life, but we could still

00:37:16 zoom out and the community consensus is that we need some kind of liquid for life to originate

00:37:24 and to survive because molecules have to react.

00:37:28 You don’t have a way that molecules can interact with each other.

00:37:31 You can’t really make anything.

00:37:32 And so when we think of all the liquids out there, water is the most abundant liquid in

00:37:38 terms of planetary materials.

00:37:39 There really aren’t that many liquids.

00:37:40 Like I mentioned, liquid rock, way too hot for life.

00:37:44 We have some really cold liquids, like almost gasoline, like ethane and methane lakes that

00:37:49 have been found on one of Saturn’s moons, Titan.

00:37:52 That’s so cold though.

00:37:53 And for exoplanets, we can’t study really cold planets because they’re just simply too

00:37:57 dark and too cold.

00:38:00 So we usually are just left with looking for planets with liquid water.

00:38:05 And to your point, remember as we talked about how planets are less than a pixel in that

00:38:12 way to say, so we can’t see oceans on planet.

00:38:15 We’re not going to see continents and oceans, not yet anyway, but we can see gases in the

00:38:19 atmosphere.

00:38:20 And if it’s a small rocky planet, and this is going into some more detail, if we see

00:38:26 a small rocky planet with water vapor in the atmosphere, we’re pretty sure that means there

00:38:31 has to be a liquid water reservoir because it’s not intuitive in any way, but water is

00:38:37 broken up by ultraviolet radiation from the star or from the sun.

00:38:42 And on most planets when water is broken up into H and O, the H, the hydrogen will escape

00:38:47 to space.

00:38:48 Because just like when you think of a child letting go of a helium filled balloon, it

00:38:53 floats upwards and hydrogen is a light gas and will leave from the planet.

00:38:58 So ultimately if you have water, unless there’s an ocean, like a way to keep replenishing

00:39:03 water vapor in the atmosphere, that water vapor should be destroyed by ultraviolet radiation.

00:39:08 Got it, so there’s a, okay, so there’s a need for liquid, I mean, I guess it was water.

00:39:16 Is water essential or are the liquids, I mean, the chemistry here is probably super complicated.

00:39:21 It does, but you know, there’s not an infinite number of liquids.

00:39:24 There’s maybe like five liquids that can exist inside or on the surface of a planet.

00:39:28 And water is the one that exists for the largest range of temperatures and pressures.

00:39:32 And it’s also the easiest type of planet for us to find and study is one with water vapor

00:39:37 rather than a cold planet that has ethane and methane lakes.

00:39:41 What’s your personal, in terms of solar systems and planets that you’re most hopeful about

00:39:48 in terms of our closest neighbors that you kind of have a sense that there might be somebody

00:39:57 living over there, whether it’s bacteria or somebody that looks like us.

00:40:02 I’m hopeful that every star nearby has a planet.

00:40:06 That has some life.

00:40:07 Because it almost has to for us to make progress.

00:40:09 We have to have that dream condition.

00:40:12 So the dream condition is like life is just super abundant out there.

00:40:16 Yeah, the dream, yes, the dream condition is that life is super abundant and it’s based

00:40:21 on the thought that if there is a planet with water and continents, that it also has the

00:40:27 ingredients for life and that the kind of base kernel thought is that if the ingredients

00:40:36 for life is there, life will form.

00:40:37 Life will form.

00:40:38 That’s what we’re holding on to.

00:40:39 With a relatively high probability.

00:40:41 Yes, that’s it.

00:40:43 Okay, let’s go into land of speculation.

00:40:46 What about intelligent life?

00:40:49 Us humans consider ourselves intelligent, surprisingly or unsurprisingly.

00:40:56 Do you think about from your perspective of looking at planets from a gas composition

00:41:02 perspective and in general of how we might see intelligent life and your intuition about

00:41:10 whether that life is even out there?

00:41:12 I think the life is out there somewhere.

00:41:14 The huge numbers of stars and planets.

00:41:17 I like to think that life had a chance to evolve to be intelligent.

00:41:21 I’m not convinced the life is anywhere near here, only because if it’s hard for intelligent

00:41:26 life to evolve, then it will be far away by definition.

00:41:29 Well, the sad thing is maybe from the artificial intelligence perspective is it makes me sad

00:41:36 there might be intelligent life out there that we’re just not like the pathways of evolution

00:41:43 can go in all these different directions where we might not be able to communicate with it

00:41:47 or even know that or even detect its intelligence or even comprehend its intelligence.

00:41:52 I’m convinced cats are more intelligent than humans that we’re just not able to comprehend

00:41:59 the measures, the proper measures of their intelligence.

00:42:04 My dog is so funny.

00:42:06 He’s a golden doodle.

00:42:07 His name’s Leo.

00:42:08 We joke that he’s either a really dumb dog and sorry, he’s not here to defend himself,

00:42:12 but he’s either really dumb or he’s a super genius just pretending to be dumb.

00:42:16 Yeah.

00:42:17 And it’s possible he’s a multidimensional projection of alien life here monitoring one

00:42:25 of the top scientists in the world trying to find aliens just to make sure that humans

00:42:33 don’t get out of hand.

00:42:34 That’s funny.

00:42:35 Oh, I’m definitely going to go in and ask him about that when I get home.

00:42:39 She’s onto something.

00:42:40 Yeah.

00:42:41 What might we look for in terms of signs of intelligent life?

00:42:46 From your toolkit, do you think there are things that we might be able to use or maybe

00:42:54 in the next couple of decades discover that would be different than life that’s like bacteria,

00:43:00 that’s primitive life?

00:43:03 I still love SETI, Search for Extraterrestrial Intelligence.

00:43:06 I like to hope that if there is a civilization out there, they’re trying to send us a message.

00:43:10 I think, like, think about it, I don’t know.

00:43:13 What are your thoughts?

00:43:14 Like, if you think about our Earth, there’s no structure we’ve built that intelligent

00:43:18 civilizations could see from far away.

00:43:20 There’s literally nothing, not even the Great Wall of China.

00:43:23 And so to think, like, why would this other civilization build a giant structure that

00:43:27 we could see?

00:43:28 Yeah, so with SETI, the idea is that we’re both trying to hear signals and send signals,

00:43:33 right?

00:43:34 Well, we haven’t sent one.

00:43:35 They call that METI, messaging.

00:43:37 And there’s a big kind of fear over METI, because do you want to tell them you’re here?

00:43:42 It’s kind of this, like, let’s wait till they call us.

00:43:45 Yeah.

00:43:46 It’s like a dating game, you have to, like, how many days do I wait before I call, kind

00:43:51 of thing.

00:43:52 Yeah.

00:43:53 But the funny thing is, if no one’s sending us a message, if everybody’s only listening,

00:43:57 how do you make progress?

00:43:59 That’s right.

00:44:00 And, I mean, but there’s also, there’s the Voyager spacecraft that we have these little

00:44:04 pixels of robots flying out all over the place.

00:44:09 Some of them, like the Voyager, reach out really far.

00:44:13 And they have some stuff on them.

00:44:15 Okay, I just…

00:44:16 We do, we have the Voyager, but they’re not really going anywhere in particular.

00:44:19 And they’re moving very, very slowly on a cosmic scale.

00:44:21 Yeah.

00:44:22 And me saying they’re far is kind of silly.

00:44:24 Yeah.

00:44:25 It’s all relative in astronomy.

00:44:26 It’s all relative.

00:44:27 Yeah.

00:44:28 Yeah.

00:44:29 I just…

00:44:30 So from the, if you look at Earth from an alien perspective, from visually and from

00:44:36 gas composition, I wonder if it’s possible to determine the degree of maybe productive

00:44:44 energy use.

00:44:45 I wonder if it’s possible to tell, like, how busy these Earthlings are.

00:44:51 Well, let’s zoom out again and think about oxygen.

00:44:55 So when cyanobacteria arose like billions of years ago and figured out how to harness

00:45:00 the energy of the sun for photosynthesis, they reengineered the entire atmosphere.

00:45:05 20% of the atmosphere has oxygen now.

00:45:09 Like that is a huge scale.

00:45:11 You know, they almost poisoned everything else by making this, what was apparently very

00:45:15 poisonous to everything that was alive.

00:45:17 But imagine…

00:45:18 So are we doing anything at that scale?

00:45:19 Like, are we changing anything at like 20% of the Earth with a giant structure or 20%

00:45:23 of this or 20% of that?

00:45:24 Like we aren’t actually.

00:45:26 Yeah.

00:45:27 Yeah.

00:45:28 That’s humbling to think that we’re not actually having that much of an impact.

00:45:32 I know.

00:45:33 But we are because in a way we’re destroying our entire planet.

00:45:35 But it’s humbling to think that from far away, people probably can’t even tell.

00:45:40 But from the perspective of the planet, when we say we’re destroying, you know, global

00:45:45 warming, all that kind of stuff, what we really mean is we’re destroying it for a bunch of

00:45:51 different species, including humans.

00:45:54 But like, I think the Earth will be okay.

00:45:55 Oh, the Earth will be, the Earth will remain, whatever happens to us, the Earth will still

00:46:00 be here.

00:46:01 And it’ll still be difficult to detect any difference.

00:46:03 Like it’s sad to think that if humans destroy ourselves, except potentially with nuclear

00:46:09 war, it’d be hard to tell that anything even happened.

00:46:12 Yeah.

00:46:13 It’s hard to tell from far away that anything happened.

00:46:15 What about, what are your thoughts now?

00:46:17 This is really getting into speculation land.

00:46:21 You’ve mentioned exoplanets were in the realm of, you know, this is beautiful edge between

00:46:28 science and science fiction.

00:46:31 That some of us, a rare few are brave enough to walk, I think in academia, you were brave

00:46:37 enough to do that.

00:46:39 I think in some sense, artificial intelligence sometimes walks that line a little bit.

00:46:47 There is so much excitement about extraterrestrial life and aliens in this world.

00:46:52 I mean, I don’t know what, how to comprehend that excitement, but to me, it’s great to

00:46:59 see people curious because to me, extraterrestrial life and aliens is at the core, a scientific

00:47:06 question.

00:47:08 And it’s almost looks like people are excited about science.

00:47:11 They’re excited by discovery, discovery, right?

00:47:16 And then the possibility that there’s alien life that visited earth or is here on earth

00:47:21 now is, is a excitement about discovery in your lifetime, essentially.

00:47:29 I mean, what do you make, what do you make of that?

00:47:33 There’s recent events where DARPA or DOD released footage of these unmanned aerial phenomena.

00:47:44 They’re calling them now UAP.

00:47:46 They got everybody like super excited.

00:47:48 Like maybe there is like what, what, what’s, what’s here on earth.

00:47:52 Do you follow the, this world of people who are thinking about aliens that are already

00:47:58 here or have visited?

00:48:00 I don’t really follow it.

00:48:01 They follow me.

00:48:02 Because in this field, if you’re a scientist of any kind, you get, people contact us, me.

00:48:11 There’s a lot of them about, Hey, I have stuff you should see, Hey, the aliens are already

00:48:15 here.

00:48:16 I need to tell you about it.

00:48:17 And I know there are people out there who really believe there’s a psychology to it.

00:48:22 There’s a psychology to it and it’s fascinating, but okay.

00:48:25 So it’s similar to artificial intelligence, but I still, but like you, I’m still enamored

00:48:29 with the point that it is out there and that people believe so strongly.

00:48:32 And that’s so many people out there believe, believe.

00:48:37 And I don’t know, I I’m not as allergic to it as some scientists are because ultimately

00:48:44 if aliens showed up or do show up or have showed up you know, these are going to be

00:48:50 very difficult to study scientific phenomena.

00:48:55 Like in, in fact, like going back to cats and dogs, like I just, I think we should be

00:49:01 more open minded about developing new tools and looking for intelligent life on earth

00:49:08 that we haven’t yet found.

00:49:10 Or even understanding the nature of our own intelligence because it kind of is an alien

00:49:15 life form, the thing that’s living, you know, in our skull.

00:49:19 It’s so true.

00:49:20 And we don’t understand consciousness.

00:49:21 Yeah.

00:49:22 It’s true.

00:49:23 We don’t understand how biology is hard, you know, unpacking it and working it all out.

00:49:28 It’s a stretch.

00:49:29 And they say too that our thinking mind is like the tip of a pyramid and that everything

00:49:34 else is happening under the hood and, but what is happening?

00:49:37 But the thing with, so the typical scientist response to, you know, are there aliens here

00:49:42 is that we need to see major evidence, not like a sketchy picture of something.

00:49:50 We need some cold hard evidence and we just don’t have that.

00:49:53 That’s exactly right.

00:49:54 Yeah.

00:49:55 But from my perspective, I admire people that dream and I think that’s beautiful.

00:50:00 The thing I don’t like, there’s two sides of the, of the folks that probably listened

00:50:05 to this, this podcast is, oh, those that dream, I think is beautiful, that, that wander what’s

00:50:12 out there, what’s here on earth.

00:50:14 And then the other ones who are very conspiratorial and thinking that stuff is being hidden and

00:50:19 it becomes about institutions.

00:50:20 Right, right, right.

00:50:21 Okay.

00:50:22 I got it.

00:50:23 I have a funny thing to talk about that.

00:50:24 So one of my colleagues had a really good answer to that and it’s not me saying this,

00:50:28 so I can say this, but he said, look, he works with NASA, not at NASA.

00:50:32 He works with government, not in the government.

00:50:35 It’s kind of mean, but he’d say, trust me, they couldn’t hide it if they tried.

00:50:37 Do you know what I’m saying?

00:50:39 Like, we’re not smart enough or good enough.

00:50:42 Not we or not me or not you, but whoever to cover it up.

00:50:45 It just, it’s sort of a myth.

00:50:47 Yeah.

00:50:48 It makes it sad because the people at NASA, the people at MIT, the people in academia,

00:50:57 the people in these institutions and yes, even in government are often trying, they’re

00:51:03 like just curious descendants of apes.

00:51:06 They’re just, they, they want to do good.

00:51:08 They want to discover stuff.

00:51:09 They’re not trying to hide stuff.

00:51:11 In fact, most of them would, in terms of leaks, would love to discover this and release this

00:51:18 kind of stuff.

00:51:19 There’s a, did you ever watch the show called The X Files?

00:51:23 Yeah.

00:51:24 Scully and Mulder.

00:51:25 Yeah.

00:51:26 And what I love actually, I used to put it up during my talks, my public talks.

00:51:29 There’s a picture of a UFO or what looks like UFO and it says, I want to believe.

00:51:35 So that’s, that’s where I think a lot of us are coming from.

00:51:38 I want to believe.

00:51:40 And it’s so great.

00:51:41 And one time I put that up and this very, very nice couple approached me really nervous

00:51:46 afterwards and they said, Hey, can we take you out for lunch sometime?

00:51:49 And I said, sure.

00:51:50 And they were like the nicest people.

00:51:52 And just one of many who has an alien, alien abduction story and the woman, um, could never

00:51:59 have kids.

00:52:00 They were older, but they didn’t have kids, which for them was a real source of regret.

00:52:02 But it was because the aliens who had abducted her had made it so that she couldn’t have

00:52:06 kids.

00:52:07 And she had apparently something implanted behind her ear, which was somehow unimplanted

00:52:12 later.

00:52:13 And they’re just so sincere and they’re such a lovely couple and they just wanted to share

00:52:18 their story.

00:52:19 That’s a, that’s a real, whatever that is, that’s the real thing.

00:52:23 The mystery of the human mind is more powerful than any alien or, I mean, it’s as interesting

00:52:30 I think as the universe.

00:52:32 And I think they’re somehow intricately linked, maybe getting a sense of numbers.

00:52:38 How many stars are there in, um, maybe, I don’t know what the radius that’s reasonable

00:52:46 to think about.

00:52:47 I don’t know if the observable universe is like way too big to think about, but in terms

00:52:52 of when we think about how many habitable planets there are, what are the numbers we’re

00:52:56 working with in your sense?

00:52:58 What are the scale?

00:52:59 Honestly, the numbers are probably like billions of trillions of stars.

00:53:03 Yeah.

00:53:04 You know, in the UK, I think, I don’t know if we do that here, but they will call a billion

00:53:07 trillion where you put like one billion followed by a trillion.

00:53:10 Yeah.

00:53:11 It’s kind of weird, but here, I don’t even know how to say the number 10 to the 20.

00:53:14 Like if you know what that is, that’s one followed by 20 zeros.

00:53:17 That’s a big number.

00:53:18 We don’t have a name for that number.

00:53:20 There’s so many per star.

00:53:22 I think we kind of mentioned this.

00:53:23 Is there a good sense, there’s probably argument about this, but per star, how many planets

00:53:30 are there?

00:53:31 We don’t have that number yet per se, you know, we’re not really there, but some people

00:53:35 think that there’s many planets per star.

00:53:38 There’s this analogy of filling the coffee cup, like, you know, you don’t usually just

00:53:43 pour one drop, you fill it.

00:53:45 And that planetary systems, we see stars being born that have a disc of gas and dust and

00:53:51 that ultimately forms planets.

00:53:53 So the idea, this kind of concept is that planets, so many planets form too many.

00:53:58 And eventually some get kicked out and you’re left with like a full planetary system, a

00:54:02 dynamically full system.

00:54:04 And so there have to be a lot because so many form and a bunch survive.

00:54:08 I mean, that makes perfect intuitive sense, right?

00:54:11 Like why wouldn’t that happen?

00:54:12 Right.

00:54:13 Well, there’s other thoughts too, though.

00:54:16 These big planets that are really close to the star, we think they formed far away from

00:54:20 the star where there’s enough material to form and they migrated inwards.

00:54:25 And some of these planets migrating inwards due to interaction with other planets or with

00:54:28 the disc itself, they may have cleared it out.

00:54:32 And kicked other planets out of the system.

00:54:34 So there’s a lot of ideas floating around.

00:54:36 We’re not entirely sure.

00:54:39 And what about Earth like planets?

00:54:41 That’s another level of uncertainty.

00:54:43 It’s a level of uncertainty.

00:54:44 If we think of an Earth like planet being an Earth around a sun in the same orbit, an

00:54:51 Earth like planet being an Earth sized planet in an Earth like orbit about a sun like star,

00:54:55 we’re not there yet.

00:54:56 You know, we’re not able to detect enough of those to give you a hard number.

00:55:00 Some people have extrapolated.

00:55:03 And they will say as many as one in five stars like our sun could be hosting a true Earth

00:55:08 like planet.

00:55:09 Wow.

00:55:10 On the topic of space exploration, there’s been a lot of exciting developments with NASA,

00:55:15 with SpaceX, with other companies successfully getting rockets into space with humans and

00:55:23 getting them to land back, especially with SpaceX.

00:55:27 What are your thoughts about Elon Musk and SpaceX, Crew Dragon, while working with NASA

00:55:33 to launch astronauts?

00:55:35 What’s your sense about these exciting new developments?

00:55:39 Well, SpaceX and other so called commercial companies are only good news for my field,

00:55:46 because they’re lowering the cost of getting to space by having reusable rockets.

00:55:50 It’s just been it’s incredible.

00:55:52 And we need cheaper access to space.

00:55:53 So from a very practical viewpoint, it’s all good.

00:55:56 Without getting people, there’s this dream that we have to go to Mars, boots on Mars.

00:56:01 Boots on Mars.

00:56:03 What do you think about that?

00:56:04 You mentioned probes.

00:56:06 What’s the value of humans?

00:56:08 Is that interesting to you from both scientific and a human perspective?

00:56:13 Human mostly.

00:56:14 I think it’s such in our desire to explore because part of what it means to be human.

00:56:19 So wanting to go to another planet and be able to live there for some time.

00:56:23 It’s just just what it means to be human.

00:56:26 You know, oftentimes in science and engineering, big, huge discoveries are made when we didn’t

00:56:32 intend to.

00:56:33 So often this kind of pure exploratory type of research or this pure exploration research,

00:56:37 it can lead to something really important like the laser, we couldn’t really live without

00:56:41 that now.

00:56:42 At the grocery, you scan your foods, there’s surgery that involves lasers, GPS, we all

00:56:46 use our GPS.

00:56:47 We don’t have GPS because someone thought, hey, it’d be great to have a navigation system.

00:56:53 And so I do support, I do, I just, but I really think it comes primarily just from the desire

00:56:58 to explore.

00:56:59 Do you think something, there’s a lot of criticism and a lot of excitement about Mars.

00:57:06 Do you think there’s value in trying to go to put humans on Mars, first of all, and second

00:57:12 of all, colonize Mars?

00:57:15 Do you think there’s something interesting that might come from there?

00:57:18 I’m convinced there will be something interesting.

00:57:20 I just don’t know what it is yet, but I don’t think, I don’t think having some commercial

00:57:24 value or value in the metric of something useful is really what’s motivating us.

00:57:29 So really, you see, exploration is a long term investment into something awesome that

00:57:33 eventually will be commercial value.

00:57:35 I do actually.

00:57:36 Yeah.

00:57:37 I do.

00:57:38 So what about visiting, okay, I apologize, but Amy, there’s an exciting longing to visit

00:57:48 Earth like planets elsewhere.

00:57:51 So what’s the closest Earth like planet you think is worth visiting and how hard is it?

00:57:59 Wow, it is very hard.

00:58:01 I mean, our nearest, call it Earth mass planet, it’s orbiting a star very different from

00:58:05 our own sun, an M Dwarf star, a small red star, Proxima Centauri.

00:58:10 It’s over four light years away and we can’t travel at the speed of light.

00:58:15 We can’t even travel, I mean, it would take tens of thousands of years to get there with

00:58:18 conventional methods.

00:58:19 So, you know, the movies like multigenerational, yeah, this movie Passenger, have you seen

00:58:23 that movie?

00:58:24 Passenger.

00:58:25 No.

00:58:26 It’s about a big spaceship that is traveling to another planet and everyone’s hibernating.

00:58:30 I won’t give you the spoiler alert because one person wakes up and then it’s kind of

00:58:33 a problem.

00:58:34 Okay, got it.

00:58:35 But yeah, the multigenerational ships, I mean, when you think about where we’re headed as

00:58:40 a species, maybe we don’t send people, maybe we end up sending raw biological materials

00:58:48 and instructions to print out humans, it sounds kind of farfetched, but already we’re printing

00:58:54 like liver cells in the lab and beating heart cells, we’re starting to reconstruct body

00:59:01 parts.

00:59:02 I mean, the thing is, it is so hard to get to another planet that this thought of printing

00:59:06 humans or printing life forms actually could be easier.

00:59:09 Yeah, that’s somehow so sad to think, to think of the idea that we would launch a successful

00:59:16 spaceship that has multigenerational, like non human life and it’s going to reach other

00:59:23 intelligent life and by the time they figure out where it came from, human civilization

00:59:30 will be extinct.

00:59:31 Wow.

00:59:32 Yeah, that is really, I mean, that’s, so that’s one, there’s a, there’s a tempting thing to

00:59:36 think about.

00:59:37 What are the possible trajectories?

00:59:38 So, you know, Elon keeps talking about multi planetary, us becoming multi planetary species.

00:59:47 I mean, sure, Mars is a part of that, but like the dream is to really expand outside

00:59:55 the solar system.

00:59:57 And it’s, it’s not clear, just like, as you said, like what the actual scientific engineering

01:00:02 steps that are required to take, it seems like so daunting, so daunting.

01:00:08 So like this, the smart thing seems to be to do the most achievable near daunting task,

01:00:15 even if there doesn’t seem to be a commercial application, which I think is colonizing

01:00:20 Mars.

01:00:21 But like from your perspective, is there some Manhattan project style, huge project in space

01:00:30 that we might want to take on and you’ve had roles.

01:00:34 You had scientists hat roles and then you also had roles in terms of being on like committees

01:00:39 and stuff, determining where funding goes and so on.

01:00:42 So like, is there a huge like multi trillion, we’ve been throwing the T word around recently

01:00:48 a lot, but these huge projects that we might want to take on?

01:00:52 Well, first of all, we want to find the planets like earth first, like just even finding those

01:00:56 earth like planets is a billion dollar endeavor, billions of dollars endeavor.

01:01:01 And that’s so hard because an earth is so small, so less massive, and so faint compared

01:01:06 to our sun.

01:01:08 It’s the proverbial needle in a haystack, but worse.

01:01:10 And we need very sophisticated space based telescopes to be able to find these planets

01:01:15 and to look, look at them and see which ones have water and which ones have signs of life

01:01:19 on them.

01:01:20 Yeah, the, the star shade project that you’re part of, star shade, star shade, yeah, this

01:01:24 is probably the most badass thing I’ve ever seen.

01:01:26 Right.

01:01:27 You know what’s interesting?

01:01:28 Can you describe what it is?

01:01:29 So what’s amazing about star shade is it was first conceived of in the 1960s.

01:01:34 Imagine that and revisited every decade until now when we think we can actually build it

01:01:38 and star shade is a giant specially shaped screen.

01:01:42 It is about, there’s different versions of it, but think about 30 meters in diameter.

01:01:47 So you’re blocking out the sun.

01:01:49 You’re effectively blocking out the star so that you can see the planet directly and star

01:01:54 shade would have a spacecraft attached to it and it would fly in space far away from

01:01:58 Earth’s gravity and it would have to formation fly with a space telescope.

01:02:03 So the idea is that star shade blocks out the starlight in a very careful way and it

01:02:08 has to block that starlight out so that the planet that is 10 billion times fainter than

01:02:13 the star, that only the planet light goes to the telescope.

01:02:17 Yeah.

01:02:19 So in formation, meaning the telescope flies in, you gave a presentation on this, but like

01:02:24 it, it would fly like in, um, this is extremely high precision endeavor.

01:02:30 Yeah.

01:02:31 We had this analogy like asking a friend to hold up a dime five miles away perfectly.

01:02:37 Like at the perfect line of sight with you.

01:02:40 And the shape of it is pretty cool.

01:02:41 I mean, uh, I don’t know exactly what the physics of that, like what the optics are

01:02:45 that require that shape.

01:02:47 I can tell you, it turns out that if you block out a star, imagine blocking out a star with

01:02:51 a circle circularly or a square shaped screen, you wouldn’t actually be blocking it because

01:02:57 the star acts like a wave.

01:02:58 The starlight can act like a wave and it would actually bend around the edges of the screen.

01:03:03 And so instead of blocking out the light, you’re expecting to see nothing.

01:03:06 You would see ripples and the analogy that I love to give, it’s like throwing a pebble

01:03:11 in a pond.

01:03:12 You know, you get those ripples, you get these concentric ripples and they go out and light

01:03:16 would do something quite similar.

01:03:18 You’d actually see ripples of light and those ripples of light, they’re actually way brighter

01:03:23 than the planet we’d be looking for.

01:03:26 So they would introduce this noise that’s a noise.

01:03:29 And so the star shade, it’s like a mathematical solution to the problem of diffraction it’s

01:03:33 called.

01:03:35 And this is what the first person who thought about star shape in the 1960s worked out the

01:03:39 mathematical shape or one salute, one family of solutions.

01:03:43 And the idea is that when the star shade, this very special shape, like a giant flower

01:03:48 with petals, when it blocks out the light, the light bends around the edges, but interacts

01:03:53 with itself in a way to give you a very, very dark image.

01:03:57 It would be like throwing a pebble in a pond and instead of getting ripples, the pond would

01:04:02 be perfectly smooth, like incredibly smooth to one part in 10 billion.

01:04:06 And all the waves would be on the outer edges, far away from where you drop that pebble.

01:04:11 And so this camera would be able to get some signal from the planet then.

01:04:19 Yes, and it would be hard because the planet is so faint.

01:04:22 But with the star out of the way, the glare of that bright, bright, bright star, with

01:04:25 that out of the way, then it becomes a much more manageable task.

01:04:30 So how do we get that thing out there?

01:04:32 We’re working with unlimited money.

01:04:34 Okay, we’re working with unlimited money.

01:04:35 We have some more engineering problems to solve, but not too many more.

01:04:39 We’ve been burning down our so called tall pole list.

01:04:43 What kind of list?

01:04:44 We call it technology tall pole.

01:04:47 It’s the phrase where you have to figure out what are your hardest problems and then break

01:04:51 those down to solve.

01:04:53 So the star shade, one of the really hard problems was how to formation fly at tens

01:04:57 of thousands of kilometers.

01:04:59 It’s like, wow, that is insane.

01:05:02 And the team broke that down actually into a sensing problem because of the star shade.

01:05:06 How do you see the star shade precisely enough to control it?

01:05:10 Because if you’re shining a flashlight, you know the beam spreads out.

01:05:13 So the star shade has a beacon, an LED or a laser, it’s going to spread out so much

01:05:17 by the time it gets to the telescope.

01:05:19 The problem wasn’t how do you tell the star shade how to move around fast enough to stay

01:05:23 in a straight line.

01:05:24 The problem was how are you able to sense it well enough?

01:05:27 So problems like that were broken down and money that came from NASA to solve problems

01:05:32 is put towards solving it.

01:05:34 So we’ve got through most of the hard problems right now.

01:05:37 Another one was that star shade, even though it’s looking at a star, light from our own

01:05:41 sun could hit the edges of the star shade and bounce off into the telescope, believe

01:05:46 it or not.

01:05:48 And that would actually ruin it because we’re trying to see this tiny, tiny signal.

01:05:52 So then the question is how do you make a razor thin edge?

01:05:55 Those pedal edges would have to be like a razor.

01:05:58 What materials can you use?

01:05:59 So there’s a series of problems like that.

01:06:01 Wow.

01:06:02 So there’s a materials problem in there?

01:06:03 Some of them.

01:06:04 Mm hmm.

01:06:05 Wow.

01:06:06 And there’s one.

01:06:07 So we almost finished solving all those problems and then it’s just a matter of building one

01:06:12 and testing it in a full scale size facility and then building the telescope.

01:06:18 It’s just a matter of time to build everything and get it, get it up for launch.

01:06:22 So this is an engineering close engineering project.

01:06:26 It’s a real engineering project.

01:06:28 I actually can tell you about two other projects that are not mine.

01:06:32 I like to call, call star shade mine because it was my project that I helped make it mainstream

01:06:38 without line is constantly shifting.

01:06:40 When I started, when I got this leadership role on star shade, I remember telling people

01:06:44 about it and it was definitely not on the mainstream okay line.

01:06:47 It was on the giggle factor side of the line and people would just laugh like that’s dead.

01:06:52 Like you can never formation fly or they’d say, why are you working on that?

01:06:55 That’s just so not, it’s not so awesome.

01:06:58 There’s a, there’s a few things you’ve done in your life and that’s when I first saw star

01:07:01 shade, I was like, what, really?

01:07:04 And then like it sinks in.

01:07:07 I mean, it’s the same thing I felt with like Elon Musk or certain people who do crazy stuff

01:07:11 and like, and then, and they get, they actually make it work.

01:07:15 I mean, if you get star shade information flying to like together, I mean, how awesome

01:07:22 is that if you actually make that happen, even like from a robot, I’m sorry, from the

01:07:27 robotics perspective, even if it doesn’t give us good data, that’s just like a cool

01:07:31 thing to get out there.

01:07:33 I mean, it’s really exciting.

01:07:34 Really cool.

01:07:35 So there’s two other topics that aren’t mine, but I still love them.

01:07:39 One of them, let’s just talk about it briefly because it’s not a probe, but it’s the idea

01:07:43 to send a telescope very far away to 500 times the earth sun distance.

01:07:47 And this is way farther than the Voyager spacecrafts are right now.

01:07:51 And to use our sun as a gravitational lens, to use our sun to magnify something that’s

01:07:56 behind it.

01:07:59 It’s got to sink in for a minute.

01:08:00 Exactly.

01:08:01 But I mean, I don’t know what the physics of that is, like how to use the sun.

01:08:05 In astronomy, and Einstein thought about this initially, we can use a massive objects, bend

01:08:11 space.

01:08:12 And so light that should be traveling like straight, it actually travels around the warped

01:08:16 space.

01:08:18 And somehow you figure out a way to use that for magnification.

01:08:23 You have a way to use that for magnification.

01:08:25 That’s right.

01:08:26 There are galaxies that are lensed, so called gravitational lens by intervening galaxy clusters

01:08:33 actually.

01:08:34 And there are microlensing events where stars get magnified as an unseen gravitational lens

01:08:40 star passes in between us and that very distant star.

01:08:43 It’s actually a real tool in astronomy.

01:08:45 Yeah, using gravitational lensing to magnify because it bends more rays towards you than

01:08:49 normally you’d normally see.

01:08:52 And again, we’re trying to get more higher resolution images that are basically boiled

01:08:58 down to light.

01:08:59 Well, it boils down to light.

01:09:01 And then you can maybe get more information about.

01:09:04 Well, in this case, you would ask me, let’s say, if this thing could get built, it would

01:09:10 take like something like they like to say 25 years to get from here to there, 25 years

01:09:15 and then it could send some information back to us.

01:09:18 And then you’d say, so Sarah, how many pixels?

01:09:20 And I wouldn’t say one or less than one.

01:09:21 I’d say, you know, it could be like 10 by 10 pixels, it could be 100 pixels, which would

01:09:26 be awesome.

01:09:27 I mean, that’s still crazy that we can get a lot of information from that.

01:09:30 Crazy, right.

01:09:31 And it’s crazy for a lot of other reasons, because again, you have to line up the sun

01:09:34 and your target.

01:09:35 You’d only have one telescope per target, because every star is behind the sun in a

01:09:39 different way.

01:09:42 So it’s a lot of complicated things.

01:09:43 What about the second?

01:09:44 The second one, it’s called star shot.

01:09:48 You know, star shot means like big dreams and it’s an initiative by the Breakthrough

01:09:53 Foundation.

01:09:55 And star shot is the concept to send thousands of little tiny spacecraft, which they now

01:10:02 call star chip.

01:10:03 So instead of star ship, it’s star chip.

01:10:06 And there’s a little chip and the star chip, so like sending like thousands of little turtles

01:10:13 being born, they’re not all going to make it.

01:10:15 The idea is to send lots of them, and each of these star chips, once they’re launched

01:10:20 into, I guess, low Earth orbit, they will deploy a solar sail that’s a few meters in

01:10:26 diameter.

01:10:27 And the idea is that on Earth, we would have a bank of, this one is still a bit on the

01:10:34 other side of the line, but we’d have a bank of telescopes with lasers that would be like

01:10:40 a gigawatt power and these lasers would momentarily shine upwards and accelerate, they’d hit these

01:10:48 sails.

01:10:49 They’d be like a power source for the sail and would accelerate the sails to travel at

01:10:54 about a 20th the speed of light.

01:10:57 Is that as crazy as it sounds?

01:10:59 Well, like any good engineering project, it has to be broken down into the crazy parts.

01:11:05 And the Breakthrough Initiative, like to their huge credit, is sponsoring, you know, getting

01:11:11 over these, actually, they’ve listed initially, they listed 19 challenges, so it’s broken

01:11:16 down to concrete things.

01:11:17 Like one of them is, well, you have to buy the land and make sure the airspace is okay

01:11:21 with you sending up that much power overhead.

01:11:24 Another one is you have to have material on the sail where the lasers won’t just vaporize

01:11:29 it.

01:11:30 So there’s a lot of issues, but anyway, these sails would be accelerated to 20th the speed

01:11:33 of light and their journey to the nearest star would no longer be tens of thousands

01:11:38 of years, but could be 20 years, okay, 20, so it’s not as bad as tens of thousands.

01:11:45 And these thousands or whatever, however many make it, they’ll go by the nearest star system

01:11:52 and snap some images and radio the information back to Earth because they’re traveling so

01:11:57 fast they can’t slow down, but they’ll zoom by, take some photos, send it back.

01:12:01 Hi, Rez.

01:12:02 See, just what I want you to pause on for a second is that just by making that a real

01:12:06 concept and the money given won’t make it happen, but what it’s done is it’s planted

01:12:11 the seed and it’s shifted that line from what is crazy to what is a real project.

01:12:15 It’s shifted it just ever so slightly enough, I think, to plant the seed that we have to

01:12:20 find a way to somehow find a way to get there.

01:12:23 That is, again, to stay on that, that is so powerful.

01:12:26 Make a big, crazy idea and break it down into smaller, crazy ideas, order it in a list,

01:12:34 and knock it out one at a time.

01:12:38 I don’t know, I’ve never heard anything more inspiring from an engineering perspective

01:12:43 because that’s how you solve the impossible things.

01:12:46 So you open your new book discussing Rogue Planet, PSO, J318, I never said this out loud,

01:12:55 PSO 1.522, so a Rogue Planet, which is just this poetic, beautiful vision of a planet

01:13:03 that, as you write, lurches across the galaxy like a rudderless ship wrapped in perpetual

01:13:10 darkness, its surface swept by constant storms, its black skies raining molten iron.

01:13:18 Just like the vision of that, the scary, the darkness, just how not pleasant it is for

01:13:27 human life, just the intensity of that metaphor, I don’t know.

01:13:32 And the reason you use that is to paint in a feeling of loneliness, I think, and despair.

01:13:43 And why, maybe on the planet side, why does it feel, maybe it’s just me, why does it feel

01:13:53 so profoundly lonely on that kind of planet?

01:13:57 Like what…

01:13:59 I think it’s because we all want to be a part of something, a part of a family, or a part

01:14:06 of a community, or a part of something.

01:14:10 And so, our solar system, and by the way, I only, it’s sort of like when you treat yourself

01:14:16 to like eating an entire tub of ice cream, like I sometimes treat myself to imagine things

01:14:21 like this and not just be so cut and dried.

01:14:25 But when you imagine that, this planet’s not part, because I don’t want to give emotions

01:14:28 to a planet per se, but the planet’s not part of anything.

01:14:31 It’s somehow, it’s just all on its own, just kind of out there without that warm energy

01:14:37 from its sun, it’s just all alone out there.

01:14:40 To me, it was this little discovery that I actually feel pretty good being part of this

01:14:45 solar system.

01:14:47 It felt like we have a sun, we have like a little family, and it felt like it sucked

01:14:52 for the rogue planet to just floating about, not floating, flying rudderless.

01:14:59 By the way, how many rogue planets are there in your sense?

01:15:04 We don’t know totally.

01:15:05 I mean, there’s some rogue planets that are just born on their own.

01:15:08 I know that sounds really weird to be, how can you be born an orphan?

01:15:11 But they just are, because most planets are born out of a disc of gas and dust around

01:15:17 a star.

01:15:18 But some of these small planets are like totally failed stars.

01:15:21 They’re so failed, they’re just small planets on their own.

01:15:24 But we think that there’s probably, honestly, there’s another path to a rogue planet.

01:15:29 That’s one that’s been kicked out of its star system by other planets, like a game of billiard

01:15:33 balls.

01:15:34 It just gets kicked out.

01:15:35 We actually think there’s probably as many rogue planets as stars.

01:15:39 No flying out there, fundamentally alone.

01:15:44 So the book is a memoir, is about your life, and it weaves both your fascination with planets

01:15:56 outside the solar system and the path of your life, and you lost your husband, which is

01:16:05 a kind of central part of the book that created a feeling of the rogue planet.

01:16:15 By the way, what’s the name of the book?

01:16:17 The name of the book is The Smallest Lights in the Universe.

01:16:21 What’s up with the title?

01:16:22 What’s the meaning?

01:16:23 The title has a double meaning.

01:16:25 On the face of it, it’s the search for other Earths.

01:16:27 Earths are so dim compared to the big, bright, massive star beside them.

01:16:32 Searching for the Earths is like searching for the smallest lights in the universe.

01:16:38 It has this other meaning, too.

01:16:42 I really hope that you or the other people listening never get to the place where you’ve

01:16:49 fallen off the cliff into this horrible place of huge despair.

01:16:56 And once in a while, you get a glimmer of a better life, of some kind of hope.

01:17:01 And those are also the smallest lights in the universe.

01:17:03 Well, maybe we can tell the full story before we talk about the glimmer of hope.

01:17:11 What did it feel like to first find out that your husband, Mike, was sick?

01:17:17 It was incredibly frustrating.

01:17:19 Like, lots of us have had some kind of problem that the doctors completely ignore.

01:17:25 Just that they kept blowing him off.

01:17:27 It’s nothing.

01:17:28 Are they paid to just say it’s nothing?

01:17:30 I mean, it’s just insane.

01:17:32 I was just so angry.

01:17:34 And we finally got to a point where he was really sick.

01:17:37 He was like in bed, not able to move, basically.

01:17:41 And it turned out all the things they ignored and not done any tests, he had like a 100%

01:17:47 blockage in his intestine.

01:17:48 Like 100%.

01:17:49 Like nothing could get out, nothing could get in.

01:17:53 And it was pretty, pretty shocking to even hear then that it could be nothing.

01:17:58 What was the progression of it in the context of the maybe the medical system, the doctors?

01:18:03 I mean, what did it feel like?

01:18:05 Did you feel like a human being?

01:18:08 I felt like a child.

01:18:11 Like the doctors were trying to water down the real diagnosis or treat us like we couldn’t

01:18:19 know the truth or they didn’t know.

01:18:21 You know, I felt mixed like, it’s not a good situation if you think the doctor either has

01:18:24 no idea what he or she is doing, or if the doctors purposely, let’s just say lying to

01:18:29 you to sugarcoat it.

01:18:30 Like, I didn’t know which one of it was, but I knew it was one of those.

01:18:34 What were the things he was suffering from?

01:18:37 Well, initially, he just had a random stomach ache.

01:18:39 I hate to say that out loud because I know a lot of people will have a random stomach

01:18:43 ache.

01:18:44 But so he just had a bad stomach ache and then, hmm, this is weird.

01:18:47 A few days later, another bad stomach ache, kind of gets worse.

01:18:50 Might go away for a few weeks, might come back.

01:18:52 And at the time, all I knew was my dad had had that same thing.

01:18:56 Not the same identical system, but he had these really weird pains and he ended up having

01:19:01 the worst diagnosis.

01:19:03 One of the worst diagnoses you can get from a random stomach ache is pancreatic cancer

01:19:07 because the time, the pancreas, like you can’t feel anything, so by the time you feel pain,

01:19:12 it’s too late.

01:19:13 It’s spread already.

01:19:14 So I was just like, beside myself, I’m like, this is like, wow, this guy, he’s got a random

01:19:19 stomach ache.

01:19:20 All I know is another man I loved had a random stomach ache and it didn’t end well.

01:19:24 How did you deal with it emotionally, psychologically, intellectually, as a scientist?

01:19:30 What was that like, that whole, because it’s not immediate.

01:19:34 It’s a long journey.

01:19:35 It’s a long journey and you don’t know where the diagnosis is going.

01:19:38 So anyone who’s suffered from a major illness, there’s like always branches in the road.

01:19:44 So he had this intestinal blockage.

01:19:47 I can’t imagine someone in their 40s having that and that be normal.

01:19:50 But the doctor is like, it could be nothing, could just cut it out.

01:19:54 You don’t need most of your intestine, it’s a repeating pattern.

01:19:56 Just cut that out, it could be fine.

01:19:57 But it ended up not being fine and he was diagnosed as being terminally ill.

01:20:01 Well, it really changed my life in a huge way.

01:20:04 First of all, I remember immediately one summer, the summer when this happened, I started asking

01:20:09 everyone I knew.

01:20:10 I would ask you, I don’t know if it’s smart of my job to put you on the spot, I’d say,

01:20:15 you have one year to live or two or three, what will you do differently about your life

01:20:19 now?

01:20:20 Lex, you have one year to live, what would you do?

01:20:26 I mean, it’s hard.

01:20:27 I don’t know if you want to answer that.

01:20:28 No, no, no.

01:20:29 I think about it a lot.

01:20:30 I mean, that’s a really good thing to meditate on.

01:20:33 We can talk about maybe why you bring that up, if it is or not a heavy question.

01:20:41 But I get, I think about mortality a lot and for me, it feels like a really good way to

01:20:52 focus in on is what you’re doing today, the people you have around you, the family you

01:20:57 have, does it bring you joy?

01:21:04 Does it bring you fulfillment?

01:21:07 And basically, for me, long ago, try to be ready to die any day.

01:21:19 So like today, I kind of woke up, look, if I was nervous about talking to you, I really

01:21:27 admire your work and the book is very good and it’s super exciting topic.

01:21:33 But then, you know, there’s this also feeling like, if this is the last conversation I have

01:21:37 in my life, you know, if I die today, will this be, will this be the right, like am I

01:21:43 glad today happened and it is, and I am glad today happened.

01:21:48 So that’s the way.

01:21:49 And that’s so unique.

01:21:50 I never got that answer from a single person.

01:21:54 The busyness of life, there’s goals, there’s dreams, there’s like planning, plans.

01:22:00 Very few people make it happen.

01:22:02 That’s what I learned.

01:22:04 And so a lot of these people.

01:22:05 Oh, like you run out of time.

01:22:07 It’s not so much you run out of time, but I’d come back later and be like, okay, why

01:22:09 don’t you do that?

01:22:10 And if that’s what you would do, if you’re going to die a year from now, why don’t you,

01:22:14 why don’t you make it real?

01:22:16 Simple things.

01:22:17 Spend more time with family.

01:22:18 Yeah.

01:22:19 Like why, why don’t you do that?

01:22:20 And that’s what I had an answer, it turns out, unless you usually, unless you have,

01:22:24 you really do have a pressing end of life, people don’t do their bucket lists or try

01:22:29 to change their career.

01:22:30 And some people can’t.

01:22:31 So we can’t, like for a lot of people, they can’t do anything about it.

01:22:33 And that’s, that’s fine.

01:22:34 But the ones who can take action for some reason, never do.

01:22:38 And that was one of the ways that Mike’s death or at the time his impending death really,

01:22:44 really affected me.

01:22:45 Cause you know, for these sick people, what I learned, he had a bucket list and he was

01:22:48 able to do some of the bucket lists.

01:22:50 It was awesome.

01:22:51 But he got sick pretty quickly.

01:22:54 So if you do only have a year to live, it’s ironic cause you can’t do, you can’t do the

01:22:58 things you wanted to do because you get too sick too fast.

01:23:01 What were the bucket list things for you that you realized like, what am I doing with my

01:23:05 life?

01:23:06 That was the major concept of him.

01:23:08 After he died, I didn’t know.

01:23:09 Like I, I was just lost because when something that profound happens, all the things I was

01:23:16 doing, most of the things I was doing were just meaningless.

01:23:20 It was so tough to, to find an answer for that.

01:23:23 And that’s when I settled on, I’m going to devote the rest of my life to trying to find

01:23:28 another earth and to find out, to find that we’re not alone.

01:23:37 What is that longing for connection with others?

01:23:42 What’s that about?

01:23:43 What do you think?

01:23:44 Why is that so full of meaning?

01:23:45 I don’t know why.

01:23:46 I mean, I think it’s how we’re hardwired.

01:23:48 Like one of my friends some time ago, actually when my dad died, he never heard someone say

01:23:54 this before, but he’s like, Sarah, you know, why are we evolved to take death so harshly?

01:24:01 Like what kind of society would we be if we just didn’t care people died?

01:24:05 That would be a very different type of world.

01:24:07 How would we as a species have got to where we are?

01:24:11 So I think that is tied hand in hand with why do we, why do we seek connection?

01:24:16 It’s just that what we were talking about before, that subconsciousness that we don’t

01:24:20 understand.

01:24:21 Yeah.

01:24:22 A couple, you know, the other side, the flip side of the coin of connection and love is

01:24:28 a fear of loss.

01:24:31 It’s like that was, again, I don’t know, that’s what makes you appreciate the moment is that

01:24:36 the thing ends.

01:24:37 Yeah.

01:24:38 It’s definitely a hard one.

01:24:40 The thing ends, but, and it’s hard to not, you wouldn’t want to limit.

01:24:45 Like it’s like my dog who I love so much, I’ll start to cry.

01:24:49 Like I can’t think about the end.

01:24:50 I know he’ll age much faster than I will.

01:24:52 And someday it will end.

01:24:53 Right.

01:24:54 But it’s too sad to think of, but should I not have got a dog?

01:24:57 Right.

01:24:58 Should I have not brought this sort of joy into my life because I know it won’t be forever.

01:25:02 It’s

01:25:03 well, there’s a, there’s a philosopher and his Becker who wrote a book, Denial of Death

01:25:08 and just, and warm with the cores.

01:25:11 And there’s another book talks about terror management theory, Sheldon Solomon.

01:25:16 I just talked to him a few weeks ago.

01:25:18 It’s a brilliant philosopher, psychologist that their theory, whatever you make of it

01:25:24 is that the fear of death is at the core of everything, everything we do.

01:25:32 So like you’re that you think you don’t think about the mortality of your dog, but you do.

01:25:40 And that’s what makes the experience rich.

01:25:42 Like there’s this kind of like in the shadows lurks the, the knowledge that this won’t

01:25:49 last forever.

01:25:51 And that makes every moment just special in some kind of a weird way that the moments

01:25:58 are special for us humans.

01:26:01 I mean, sorry to use romantic terms like love, but what do you make, what did you learn about

01:26:12 love from, from losing it, from losing your husband?

01:26:18 Well I learned to love the things I have more.

01:26:21 I learned to love the people that I have more and to not let the little things bother me

01:26:28 as much.

01:26:30 What about the rediscovery or like the discovery of the little lights in the darkness?

01:26:41 So you, the book, I think you’ve brilliantly described the dark parts of your journey.

01:26:52 But maybe can you talk about how you were able to rediscover the lights?

01:27:00 They came in many ways.

01:27:02 And the way like to think about it is like grief is an ocean, you know, with tiny islands

01:27:09 of the little, like, like the little lights.

01:27:10 And eventually that ocean gets smaller and smaller and the islands like become continents

01:27:15 with lakes.

01:27:17 So initially it’d be like the children laughing one day or my colleagues at work who rallied

01:27:22 around me and would take me away from my darkness to work on a project.

01:27:28 Later on it turned out to be a group of women my age, all widows, all with children in my

01:27:33 town.

01:27:35 And it would be, even though it was a bit morose getting together, still very joyful

01:27:40 at the same time.

01:27:42 What was the journey of rediscovering love like for you?

01:27:47 So refinding, I mean, is there some, by way of advice or insight about how to, how to

01:27:57 rediscover the beauty of life?

01:28:00 Of life.

01:28:01 It’s a hard one.

01:28:02 I think you just have to stay open to being positive and just to get out there.

01:28:09 Do you still think, do you still think about your own mortality?

01:28:13 So you mentioned that that was a thing that you meditate on as a question when it was

01:28:19 right there in front of you.

01:28:22 But do you still think about it?

01:28:23 I think I will after talking to you.

01:28:26 But no, it’s not really something I think about.

01:28:28 I mean, I do think about the search for another earth and will, will I get there?

01:28:33 Will I be able to conclude my search and is there one?

01:28:38 Like as time goes by, you know, that window to solve that problem gets smaller.

01:28:45 What would bring you, again, I apologize if this makes concrete the fact that life is

01:28:51 finite, but what, what would bring you joy if we discovered while you’re still here?

01:28:58 What would bring me joy?

01:28:59 Finding another earth, an earth like planet around a sun like star, knowing that there’s

01:29:04 at least one or more out there, being able to see water, that it has signs of water and

01:29:09 being able to see some gases that don’t belong.

01:29:12 So I know that the search will continue after I’m gone enough to fuel the next generation.

01:29:18 So just like opening the door and there’s like this glimmer of hope.

01:29:24 What do you think it will take to realize that?

01:29:25 I mean, we’ve talked about all these interesting projects, star shade, especially, but is there

01:29:29 something that you’re particularly kind of hopeful about in the next 10, 20 years that

01:29:36 might give us that, that exact glimmer of hope that there’s earth like planets out there?

01:29:43 I have to, I stand behind star shade in all cases, so, but there is this other kind of

01:29:48 field that I, that everyone is involved in because star shade is hard.

01:29:53 Earths are hard, but there are, there’s another category of planet star type that’s easier.

01:29:58 And these are planets orbiting small red dwarf stars.

01:30:02 They’re not earth like at all.

01:30:04 Think like earth cousin instead of earth twin, but there’s a chance that we might establish

01:30:08 that some of those have water and signs of life on them.

01:30:11 It’s nearer term than star shade and we’re all working hard on that too.

01:30:15 Let me ask by way of recommendations, I think a lot of people are curious about this kind

01:30:20 of stuff.

01:30:21 What three books, technical or fiction or philosophical or anything really had an impact

01:30:27 on your life and, and or you would recommend besides of course your book.

01:30:35 There’s one book I wish everyone could read.

01:30:38 I’m not sure if you’ve read it.

01:30:39 It’s actually a children’s book, like a young adult book.

01:30:42 It’s called the giver.

01:30:43 Yes.

01:30:44 And it is the book that kids in school read now.

01:30:48 And I only, sorry, that’s not, that’s wow.

01:30:52 Sorry, that, that caught me off guard.

01:30:57 So when I first came to this country, I didn’t speak much.

01:30:59 It’s really what made me, it had a profound impact on my life and a really important moment

01:31:05 because they give it to kids.

01:31:07 Like I think middle school, I think, or maybe elementary, something like that.

01:31:10 I’m so surprised you’ve even heard of this book.

01:31:12 Yeah.

01:31:13 So they give it, but like it’s the value of giving the right book to a person at the right

01:31:17 time.

01:31:18 Wow.

01:31:19 I was, I was, cause it’s very accessible.

01:31:22 Do we want to share what the story is without spoiling it?

01:31:25 Oh yeah, you can without spoiling, right?

01:31:28 It follows this boy in this very utopic society.

01:31:32 That’s like perfect.

01:31:33 It’s been all clean cut and made perfect actually.

01:31:35 And as he kind of comes of age, he starts realizing something’s wrong with his world.

01:31:41 And so it’s part of that question.

01:31:42 Are we going to evolve as, I mean, this isn’t what’s there, but it made me wonder, you know,

01:31:45 are we evolving to a better place?

01:31:47 Is there a day when we can eliminate, you know, poverty and hunger and crime and sickness

01:31:52 in this book, they pretty much have in a society that the boys in and sort of follows him.

01:31:58 And he becomes a chosen one to be like a receiver.

01:32:01 The givers, the old wise man who retains some of the harshness of the outside world so that

01:32:06 he can advise the people as a sort of boy comes of age and is chosen for the special

01:32:11 role.

01:32:12 He finds the world isn’t what he expects.

01:32:13 And I don’t know about you, but it was so profound for me because it jolts you out of

01:32:17 reality.

01:32:18 It’s like, Oh my God, what am I doing here?

01:32:19 I’m just going with the flow with my society.

01:32:22 How do I think outside the box and the confines of my society, which surely carries negative

01:32:26 things with it that we don’t realize today.

01:32:28 Yeah, and also in the flip side of that is if you do take a step outside the box on occasion,

01:32:36 what’s the psychological burden of that?

01:32:39 Like is that, is that a step you want to take?

01:32:42 Is that the journey you want to take?

01:32:44 What is that life like?

01:32:45 I don’t know.

01:32:46 I felt like from the book, you have to take it.

01:32:48 I found from the book, I never thought like now that you’re saying it, I see what you’re

01:32:52 saying.

01:32:53 The burden is huge, but I always felt like the answer is yes, you absolutely want to

01:32:56 know what’s outside.

01:32:57 But you can’t do that if you’re very, it’s hard to be objective about your own reality.

01:33:01 Yeah.

01:33:02 I mean, it’s a very human instinct, but, uh, it also, the book kind of shows that, uh,

01:33:08 it has an effect on you and this, it’s a really interesting question about our society and

01:33:14 taking a step out.

01:33:16 It’s by, uh, Lois Lowry, I think is how you pronounce it.

01:33:20 I really do hope everyone created it and it is a young adult book, but it’s still, it’s

01:33:24 incredibly, I’m really glad I only read it cause my kids got it for school.

01:33:27 I just thought, okay, well, why don’t I just see what this is about?

01:33:29 And I just, wow.

01:33:31 Yeah.

01:33:32 Yeah.

01:33:33 I think it’s also the value of education.

01:33:35 I think I’m surprised you mentioned, I’ve never really mentioned to anybody.

01:33:38 I’m sure a lot of people had the similar experience like me and maybe it’s a generational thing

01:33:44 though, because like the book came out, I think in the nineties.

01:33:46 So if you’re older than like me, that book didn’t exist when we were in middle school.

01:33:50 So I just do think a lot of people won’t have heard of it, but it’s an interesting question

01:33:54 of like those books.

01:33:58 I mean, I’m reminded often, I suppose the same is true with other subjects, but books

01:34:03 are special at the early age, like middle school, maybe early high school, those can

01:34:09 change like the direction of your life.

01:34:11 And also certainly teachers, they can change completely the direction of your life.

01:34:17 There’s so many stories about teachers of mathematics, teachers of physics, of any kind

01:34:24 of subjects basically changing the direction of a human’s life.

01:34:27 That’s like not to get on the whole, almost like a political thing, but you know, we,

01:34:36 we undervalue teachers.

01:34:38 It’s a special, it’s a special position that they hold.

01:34:42 That’s so true.

01:34:43 Yeah.

01:34:44 Well, I do have two other books or two other things.

01:34:46 One is something I came across just a few days ago, actually.

01:34:50 It’s actually a film called Picture a Scientist.

01:34:54 And when you picture a scientist, you probably don’t picture the women and women of color

01:34:59 in this film.

01:35:01 And it is a way to get outside your box.

01:35:03 I really think everyone interested in science, even just peripherally should watch this because

01:35:09 it is shocking and sobering at the same time.

01:35:12 And it talks about how, well, I think one of the messages across is, you know, we really

01:35:17 are like, I don’t know if we’re hardwired to just like people like ourselves, but we’re

01:35:22 excluding a lot of people and therefore a lot of great ideas by not being able to think

01:35:27 outside of how we’re all stereotyping each other.

01:35:30 So it’s, it’s, it’s hard to kind of convey that and you can just say, oh yeah, I want

01:35:34 to be more diverse.

01:35:35 I want to be more open, but it’s a nearly impossible problem to solve and the movie

01:35:38 really helps open people’s eyes to it.

01:35:42 This book I put third because unlike The Giver, people may not want to read it.

01:35:46 It’s not as relevant.

01:35:47 But when I was in my early twenties, I went to this big, this like 800 people large conference

01:35:56 run by the Wilderness Canoe Association in my hometown of Toronto.

01:36:00 And there was a family friend there who I met and he said, read this book, it’ll change

01:36:04 your life.

01:36:06 And it actually changed my life.

01:36:08 And it was a book called Sleeping Island by an author, PG Downs, who just coincidentally

01:36:13 lived in this area, lived in the Boston area and he was a teacher, I think at a private

01:36:17 school and every summer he would go to Canada with a canoe often by himself.

01:36:23 And he wrote this book maybe in the forties or fifties about a trip he took in the late

01:36:27 1930s.

01:36:28 And it was, I was just shocked that even at that time, although that was a long time ago,

01:36:32 there were large parts of Canada that were untouched by white people.

01:36:37 And he went up there and interacted like with the natives.

01:36:40 He called the book and had a subtitle that was called, there’s something like Journey

01:36:45 in the Barren Lands.

01:36:47 And when you go up North in Canada, you pass the tree line, just like on a mountain, if

01:36:50 you hike up a mountain, you get so far North there aren’t any trees.

01:36:53 And he wrote eloquently about the land and about being out there.

01:36:56 There weren’t even any maps of the region, like in that time.

01:37:00 And I just thought to myself, wow, like that you could just take the summer off and explore

01:37:04 by canoe and go and see what’s out there.

01:37:07 And it led to me just doing that, that very thing.

01:37:10 Of course it’s different now, but going out to where the road ends and putting the canoe

01:37:14 in the water and just, well, we had to have a plan.

01:37:16 We didn’t just explore, but go down this river, rivers with rapids and travel over lakes and

01:37:21 portages and just really live.

01:37:25 So just really explore, screw it.

01:37:27 That doesn’t like, it doesn’t explore just use from a topo map, from a topographical

01:37:31 map from the library.

01:37:33 There were scary elements about it, out of it, but part of the excitement or the joy

01:37:41 or the desire was to be scared, like it was to go out there and have live on the edge.

01:37:45 And persevere.

01:37:46 Yeah.

01:37:47 And persevere.

01:37:48 Yeah.

01:37:49 Do you have a advice that you would give to a young person today that would like to help

01:37:56 you maybe on the planetary science side, discover exoplanets or maybe bigger picture, just

01:38:03 succeed in life?

01:38:04 I do have some advice just to succeed.

01:38:06 It’s tough advice in a way, but it is to find something that you love doing that you’re

01:38:11 also very good at.

01:38:13 And in some ways the stars have to align because you’ve got to find that thing you’re good

01:38:17 at or the range of things, and it actually has to overlap with something that actually

01:38:21 you love doing every day.

01:38:23 So it’s not a tedious job.

01:38:26 That’s the best way to succeed.

01:38:27 What were the signals that in your own life were there to make you realize you’re good

01:38:33 at something?

01:38:35 What were you good at that made you pursue a PhD and it made you pursue the search?

01:38:44 I mean, that was the one sentence version.

01:38:46 In my case, it was a long slog and there were a lot of things I wasn’t good at initially.

01:38:51 But so initially, I was good at high school math.

01:38:53 I was good at high school science.

01:38:55 I loved astronomy and I realized those could all fit together.

01:38:58 Like the day I realized you could be an astronomer for a job, it has to be one of my top days

01:39:02 of my life.

01:39:03 I didn’t know that you could be that for a job and I was good at all those things.

01:39:08 And although my dad wanted me to do something more practical where he could be guaranteed

01:39:11 I could support myself was another option, but initially I wasn’t that good at physics.

01:39:16 It was a slog to just get through school and grad school is a very, very long time.

01:39:21 And ultimately, when faced with a choice and I had the luxury of choosing, knowing that

01:39:26 I was good at something and also loved it, it really carried me through.

01:39:29 Now, I asked some of the smartest people in the world the most ridiculous question.

01:39:34 We already talked about it a little bit, but let me ask again, why are we here?

01:39:42 I think you’ve raised this question in one of your presentations as like one of the things

01:39:47 that we kind of as humans long to answer and the search for exoplanets is kind of part

01:39:52 of that.

01:39:53 But what do you think is the meaning of it all, of life?

01:39:57 I wish I had a good answer for you.

01:40:02 I think you’re the first person ever who refused to answer the question.

01:40:07 It’s not so much refusing, I just, yeah, I mean, I wish I had a better answer.

01:40:11 It’s why we’re here.

01:40:12 It’s almost like the meaning is wishing there was a meaning, wishing we knew.

01:40:20 I love that.

01:40:21 That’s a great way to say it.

01:40:24 Sarah, like I said, the book is excellent.

01:40:27 I admired your work from afar for a while and I think you’re one of the great stars

01:40:33 at MIT.

01:40:34 It makes me proud to be part of the community.

01:40:37 So thank you so much for your work.

01:40:40 Thank you for inspiring all of us.

01:40:41 Thanks for talking today.

01:40:42 Thank you so much, Lynx.

01:40:45 Thanks for listening to this conversation with Sarah Seager.

01:40:47 And thank you to our sponsors, Public Goods, Power Dot, and Cash App.

01:40:53 Click the links in the description to get a discount.

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01:40:57 If you enjoy this thing, subscribe on YouTube, review it with five stars on Apple Podcast,

01:41:02 support it on Patreon, or connect with me on Twitter at Lex Friedman, spelled I’m not

01:41:07 sure how.

01:41:08 Just keep typing stuff in until you get to the guy with the tie and the thumbnail.

01:41:14 And now let me leave you with some words from Carl Sagan, somewhere something incredible

01:41:20 is waiting to be known.

01:41:23 Thank you for listening and hope to see you next time.