Think Forward: Conversations with Futurists, Innovators and Big Thinkers

Think Forward EP 142 - Hunting for Another Earth with Dr Sara Seager

• Steve Fisher • Season 1 • Episode 142

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Welcome to this special crossover episode from our other show, Going Off World.

In this episode, the hunt for alien life isn’t a sci-fi dream. It’s a patient, high-stakes investigation unfolding across labs, observatories, and space missions—and Sarah Seager is charting the course. We sit down with the MIT exoplanet pioneer to unpack how a field once defined by four puzzling worlds grew into a catalog of thousands, each challenging our assumptions about what planets can be and where life might take hold.

We trace Dr Sarah Seager’s path from early skepticism about hot Jupiters to leading-edge missions seeking signs of life in exoplanet atmospheres and even the acid clouds of Venus. The conversation blends technology, theory, and personal resilience to map the long road to finding another Earth.

If you care about exoplanets, biosignatures, Venus, and the future of discovery, this conversation is a guided tour of what it will take to spot another Earth and how that finding could reshape our place in the cosmos. If you enjoyed this episode, follow the show, share it with a friend who loves space, and leave a review to help more curious minds find us.

• how exoplanet science matured from four planets to thousands
• why hot Jupiters reshaped formation theories
• Kepler’s impact and TESS’s role in finding follow-up targets
• what biosignature gases are and why they matter
• starshade and direct imaging to see Earthlike worlds
• red dwarf habitability, tidal locking, and stellar flares
• Venus phosphine debate and sulfuric acid cloud chemistry
• realistic timelines, tech limits, and the long view
• career foundations, generalist leadership, and mentorship

Find her over at SarahSeager.com. She is also on Facebook, Instagram, LinkedIn, and a bunch of other social media platforms. You can just search for her name, Sarah Seager.

Thanks for listening to the Think Forward Podcast. You can find us on all the major podcast platforms and at www.thinkforwardshow.com as well as on YouTube under Think Forward Show.

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Thank you for joining me on this ongoing journey into the future. Until next time, stay curious, and always think forward.

SPEAKER_03:

Of course they had to. There was aliens involved. But what we found in exoplanets is that planets literally come in all allowable masses, radii, and orbits.

SPEAKER_01:

Yes.

SPEAKER_03:

Honestly, we probably have planets of every mass that can still be a planet. So two mass, the star. Yeah you know, not enough massive, it would be an asteroid or something. But literally anything that could, we literally fill it into all the decimal places.

SPEAKER_02:

Welcome, friends, and fellow big thinkers. Today we're venturing beyond our usual terrestrial futures to explore humanity's greatest cosmic question. Are we alone in the universe? Well, our guest has dedicated her life to answering this question, not through speculation or philosophy, but through rigorous science and ingenious innovation. She's an MIT professor and a MacArthur fellow. She pioneered the study of exoplanet atmospheres, developing methods to detect chemical signatures of life across vast distances of space. In a special crossover with our going off world show, we'll explore how she's searching for biosignature gases, the atmospheric fingerprints that only life can leave behind. We'll learn about her quest to find an Earth twin orbiting a distant star, her surprising work on Venus as a potential harbor for aerial life, and her role leading NASA's groundbreaking test mission. But this conversation goes beyond telescopes and scanning. It's about the future of discovery itself, how we'll recognize alien life when we find it, and what it means for humanity's place in the cosmos, and why this search for life beyond Earth is fundamentally a futurist endeavor. Her work represents an intersection of cutting-edge technology, audacious vision, and patient persistence. From developing the starshade concept to compiling exhaustive lists of potential biosignature gases, she's building the roadmap for perhaps the most significant discovery in human history. Expect to explore the questions about habitable zones, the challenges of detecting life at cosmic distances, and what it really means to find another Earth. This future's thinking in its most profound. Contemplating not just our future, but the future of life itself in our galaxy. Welcome to a special Think Forward episode: Hunting for Another Earth with Dr. Sarah Seeger. So for those who don't know you, could you provide kind of your journey?

SPEAKER_03:

Hi, everyone. I'm Professor Sarah Seeger at the Massachusetts Institute of Technology, MIT, where I've been a professor for nearly 20 years. I work primarily on exoplanets, planets orbiting stars other than the sun, where 25 years ago I started working on it and got to literally lay down the foundation for exoplanet atmospheres, which today studies are flourishing with the James Webb Space Telescope. In parallel to that, I worked on numerous space missions. Most recently, I'm proud to be leading a series of missions to Venus.

SPEAKER_02:

Did that kind of spark your path in the career, kind of your passion for space?

SPEAKER_03:

I mean it's like for training because you can always look back and rewrite history. But when I do look back at my childhood, one of the threads is certainly astronomy. And there are these punctuated memories through time. Do you have that as well?

SPEAKER_02:

Yeah. When I was about 11 or 12, I would lay on the ground outside the house in the back. We lived in a pretty rural place, but I remember distinctly I had binoculars, pretty good basic telescope to see the moon and the craters. I think what really did it for me was even through binoculars, seeing the four moons, what Galileo saw, the four moons of Jupiter, the patterns off what he documented. And I was passionately into astrophotography. So I had an old Nikon and I started to just I didn't have anything fancy to track it, but I started to capture images and things that you really couldn't see. And it was just I I wanted to study astronomy and I just became really into especially the my my passion probably would have, if I would have continued in engineering, would have been around propulsion. Because I was fascinated with the way because the way we are now and how we get off the planet's very rudimentary listen change. But when it comes to things now, Kirby Drive or just even fusion. And when I was at a conference, I met Freeman Dyson and talked to him about the Orion. He talked about the Orion Project, which was yeah, fascinating project. It never got off, it never I think of Wern of Vernon Braun was a hero for me as a kid. I mean, obviously, his past is obviously colored with a lot of things, but his genius, and it was interesting to learn about the history of how he approached and wanted to go to space. Think about it if beauty read up on your career and I and our conversation. We talked about moving from physics into astronomy. So, what was that during the university years? What was that shift? Because you always had astronomy as that ground, which you wanted.

SPEAKER_03:

Right. Well, I always loved astronomy, but you really need a background in physics to explore astronomy as a professional. When I went to undergrad, I was just trying to study general science and narrow that down to physics. Astronomy and physics were a bit separated while I was an undergrad. I what got a summer job at an observatory. But they came together later on when I got further into graduate school.

SPEAKER_02:

So what did graduate school do for you? Was it a repositioning of how you saw your career from?

SPEAKER_03:

Yeah, more of an application of physics to astronomy.

SPEAKER_02:

Yeah.

SPEAKER_03:

What are some things you remember as a kid? The star parties like things like Well, I grew up in the city, so we didn't have too many stars. But I remember the constellation Orion. I remember seeing it in the floor cold where I grew up in Canada. So I knew when Orion showed up, it was going to be winter.

SPEAKER_01:

Yeah.

SPEAKER_03:

But I also remember as a child, I had literally one experience to go away from the city one summer. My dad was a single dad, and we got to live with him in summertime. And we had a babysitter every summer to take care of us. We had this babysitter, Tom. He was a teenager, and he was shocked we'd never been camping. And how could a family never have tried that? So he borrowed all his family stuff and got my dad to drive us all away from the city one weekend. And it was just amazing. I was so lucky that it was a dark sky, no moon, clear. And I wandered out of the tent in the middle of the night and I looked up. And for the first time in my life, wow, I saw all the stars, so many stars. It was just mind-blowing. And that always stayed with me. It was just almost terrifying.

SPEAKER_02:

Yeah, it is. You feel very humbled how small you are.

SPEAKER_03:

But I had no idea what it was. No one had ever told me about it. I'd seen the stars, I'd been to the planetarium, but to see it for real for the first time stayed with me.

SPEAKER_02:

There's an adult experience from that my wife and I went to the Amazon. I went to Peru and we were in an eco village. They everything would shut down at night, but we went out on a canoe, guided to look for all kinds of stuff. But everyone's looking for climbing alligator, you know, little crocodiles. I'm looking at the sky because it's complete, it's actually the first time seeing the Milky Way, seeing also it was another hemisphere. Because we went to Africa a few years later and to see the Southern Cross, to see a completely different sky.

SPEAKER_03:

Amazing. I can imagine going there. It's just confusing, right? You're not seeing what you used to. I heard Orion's upside down.

SPEAKER_02:

Yeah, Orion wasn't in the sky at that time. What was really wild, you talk about Orion. I can completely relate because it's here in the fall in in New England. It's that crisp fall air, and you see Orion, you see the Big Dipper, you see Pleities, you see all the it's that comfort of that sky, right?

SPEAKER_03:

I find it comfort when it's in the springtime, and I know that summer spring. It's warm.

SPEAKER_02:

Well, you and I are both, you and I, you're in I'm in Metro West Boston. So for those listening, we're about an hour away from each other. But yeah, it's definitely the cold is here. You can definitely feel the crisp skies. Your early work, we want to shift to the career impact. Your early work on hot Jupiter atmospheres, that was met with a lot of skepticism. How did you maintain the conviction, staying your ground in the research for you?

SPEAKER_03:

Well, when I started working on exoplanets, there were only about four known. Today there are thousands, like several thousand known, several thousand exoplanet candidates waiting to be confirmed. At the time, the reason why there was such skepticism was we were expecting to find solar system copies, like a Jupiter many, but instead people found what was easy to find based on biases of the observing techniques, which are big planets really close to the star. And this just was ludicrous. How could you have a Jupiter mass planet many times closer to its star than Mercury is to our sun? It just makes no sense at all. And when we see disks around newborn stars, there's not enough material that close to the star to form a Jupiter mass object. So the very discovery of these early exoplanets meant that the Jupiter had to form where there is enough material and somehow it migrate inwards and then stop. So people were generally skeptical. They wanted to explain exoplanets away by astrophysical noise from the star, perhaps the stars pulsating in a certain way to mimic the planet signal. It wasn't that I was definitively 100% sure the planets were real. It was more of like starting out on an adventure that seemed exciting. It's like climbing a mountain, you know, you might not get to the top. You always know that's a possibility, but you're still going to go and try. So I partly just thought it was an amazing opportunity. Partly some people around me were convinced they were real planets, namely my thesis committee. So that was really great. But partly I knew that if the exoplanets ended up not being real, I was still gaining a valuable skill in graduate school. Thinking hard, learning how to computer program, studying radiation. And I knew I would get some kind of job.

SPEAKER_02:

Okay.

SPEAKER_03:

Finally, I wasn't committed to a career in science. What are we exploring? I had no alternative either, but I think a lot of young people are starting out, they get on a path, and you don't necessarily know it's the right path to stay on.

SPEAKER_02:

Yeah.

SPEAKER_03:

And so I think it's really common. I really want to emphasize that because I'm sure you also know a lot of young people, and most of them, a good number of young people, they've I don't say they have no idea what they're doing, but you start out on something because your parents told you, or it seemed like a natural next step. But it evolves, right? Count countless adults today, they started out doing one thing and now they're doing something else. And so I always knew that was a possibility that getting trained was why I was there. And it didn't work out, or if I didn't feel like doing it later, I would do something else.

SPEAKER_02:

Yeah, I wanted to be an astronaut, either science or flight. And I always wanted to fly as a kid. I took lessons as a kid, got my pilot's license, went to flight school, and in a year I was, yeah, I don't want to do this. It's just that your hobby is not your job thing. And my family, I come from a family that does real estate and builds, and it was something that in engineering, my father's an engineer, and he wanted me to be a specific kind of civil engineer, and I just didn't want to do that. And but when I finished my degree, my degree is an accounting of all things, right? And I'm a designer and I studied architecture, I studied product design, and it's amazing how much that fundamental skill helps run companies. I knew it would devolve, I needed something foundational.

SPEAKER_03:

Right, exactly. Let's pause on that. We need something foundational, and then it can take you on your original path. Me, I stuck to my original path, or you and many others, that foundational thing. You can leverage that, combine it with new skills you're gonna learn, apply it in new areas. So just like that, I wasn't, you said you went to pilot school, eventually you realized it's not for your career. But sometimes you can't know that until you start on that path. So I just wanted to make that I really like that part of our conversation. But I always worked with astronomy. That's what I had to guide me. And even if I didn't necessarily like what I was doing or didn't know if it was going to go anywhere, I loved astronomy so much. And I'm just really so privileged and thrilled that I get to do it as my job.

SPEAKER_02:

I'm jealous, a bit jealous of what you do. I mean, you look at the last 30 years. You said when it was just there's a couple out there that we found with the telescopes, but I keep thinking about science fiction. There was a lot, you know, Star Trek, all the speculation that these planetary systems existed. You read Doom. It was almost an expectation that we would figure it out, but many people just were that they're just stars. We really don't know. And now it's now on a search to find the smaller how Yeah, I like what you said.

SPEAKER_03:

It used to be science fiction when we were kids. Right. I don't know what Star Trek you watched. We had to watch the reruns.

SPEAKER_02:

Yeah, I don't know. I watched the reruns with my dad, but yeah, it's next generation. I watched them all.

SPEAKER_03:

Yeah, you watch them all, and but yeah, we just speculated there were planets, crazy planets with crazy life form.

SPEAKER_02:

Right. Because we could get into old science fiction conversation, but when you think about your your work has really spanned from the theoretical models to this, obviously practical space missions. How do these approaches, how do they complement each other when understanding exoplanets? Yeah. So you go from the theoretical to the practical, right? How do the approaches, how do they complement each other when you're trying to understand?

SPEAKER_03:

Yeah, that's a really good question. Traditionally, people just focus on one thing. You're either an engineer building something, yeah, or you're an observational astronomer observing something and working with data. Yeah, sure. Most people specialize in one thing, like you would be the engineer that builds the telescope or spacecraft, or you would be the person who creates an observing program and analyzes data, or you would be a theorist who makes computer models to understand the physical planet and interpret the data. I try to do all three. You know, the more you know, the better you can get your job done. So I don't pretend to be an expert in everything, but getting a deep conceptual knowledge or studying deeply two out of the three while being an expert at one. But I'm sure you have your own analogy from business, the business world. Like it pays to know more than one thing, even if you don't know all of them super well. So I bring them all together because if you want to envision a mission or lead a team, you sure have to know. You know, that's what I tell people to be the chef, the top chef, you've got to have worked on every area, basically, where you can't do the best job.

SPEAKER_02:

There's a the approach I take, the generalist's view where you have to get a certain knowledge of how things work in if you're building a software company. You have to understand the roles and the different things and certain things you can do. But there's the thing that you do as a specialist, the thing that you focus on the best of the things.

SPEAKER_03:

Yeah, exactly.

SPEAKER_02:

Knowing that, the other thing is you have to know how to hire it and how to get the right things out of people. You don't have to be the expert in it, but you have to know enough to be able to get the things from the people to get your work done, right?

SPEAKER_03:

You have to know enough to hire the right people, to know if what they're doing is legit, to steer them in the right direction, if they've sort of fallen off the main path. So that's partly why I've spent so much time studying and learning and working in many different areas, so that I can be the leader that's going to find signs of life beyond Earth.

SPEAKER_02:

Yeah, you have a really great saying I found in your research for exoplanets. Anything is possible under the laws of physics and chemistry.

unknown:

Right.

SPEAKER_02:

For anyone, anything. Yeah, go ahead.

SPEAKER_03:

You're talking about that. Even Star Trek, Star Wars, they envisioned a certain kind of planet. Of course, they had to. There was aliens involved. But what we found in exoplanets is that planets literally come in all allowable masses, radii, and orbits.

SPEAKER_01:

Yes.

SPEAKER_03:

Honestly, we probably have planets of every mass that can still be a planet. So two masses, the star, you know, not enough massive, it would be an asteroid or something. But literally anything that could, we literally fill it into all the decimal places. So half an Earth mass through, you know, up to 12, 13 Jupiter masses and every single thing in between. Same with planet size, same with planet orbits. I mean, there's a planet that has an almost cometary orbit. There are planets in between Earth and Neptune size that are very average. We don't know what they're made of. Anything is possible. Nature is more creative and clever than we are in many ways. So anything's possible.

SPEAKER_02:

How has our understanding evolved? You've you had talked about when it was four, and we now we have so many, and there's thousands now. How has our understanding evolved? Of what's kind of has there been markers, milestones, things of which brought us here to where we are?

SPEAKER_03:

Big milestones. I mean, what's cool about astronomy is anytime you get a new telescope, it opens up a new regime. For the initial telescopes that found exoplanets, they could almost only find one kind of planet. And we're really lucky that nature gave us that planet, the massive planets, the Jupiter's close to the star. So we found those right away, or not right away, but those were the first exoplanets around sun stars. The big milestone was the Kepler Space Telescope, NASA's telescope that was designated for planets only. And Kepler's job was to stare at one giant field of stars for literally four whole years of one spot. And Kepler's goal was to look for transiting planets, planets that go in front of the star, as seen from our viewpoint. And these have to be specially aligned. So they're very rare. But if you look at enough stars, you're going to catch them. And what Kepler did was because of its incredible sensitivity, our detectors got better and more sensitive. Kepler did such a phenomenal job in showing us all the kinds of planetary sizes out there. It was literally breathtaking. And Kepler's observational ability is what really launched us into what is our modern era of exoplanets.

SPEAKER_02:

Would you say that that's the technological advancement that's most excited you?

SPEAKER_03:

Well, the best, the more exciting things are always in the future for us. Okay because there's always the next big thing. But at the time, Kepler was definitely probably in all of exoplanets. It gave us the most, the largest leap forward, I would say. It found crazy things. It found compact planetary systems that are almost as flat as a record player in their orbits, with several planets orbiting tightly, all in a plane, interior to what would be Mercury or Venus's orbit. It found the most common type of planet out there is this planet between Earth and Neptune size. We have no solar system counterpart, don't know what they're made of. Kepler definitely birthed the field in a big way. It took us to the next level and generated a ton of data, so much data that lots of people could enter the field and find something to do.

SPEAKER_02:

That's great.

SPEAKER_03:

Well, also, I don't know how it works in every industry, but do you know how in the business world stuff's proprietary? You figure something out, you keep it for yourself because you got to sell. Well, NASA's for the public, it's our taxpayers' dollars at work. So our data is all made public. And not only is it made public, but it's archived nicely with different levels of data products. So you could get raw data, but you might not know what to do with it. Or you could get at the other end calibrated light curves that are kind of the end product. That was also a big boost for the community.

SPEAKER_02:

Now you have that you described in the search, there's this concept I read called Shade.

SPEAKER_03:

Star Shade.

SPEAKER_02:

So could you is that a bit different than what Kepler did?

SPEAKER_03:

Yeah, yeah. Ways to find exoplanets. So many ways, like six or seven very solid ways. And each of these ways will have their time. Like we started out with the radial velocity technique. That was the only game in town for quite a while. Then we had Kepler doing transits, and the transits are still going strong.

SPEAKER_02:

Cool. Okay.

SPEAKER_03:

So starshave will be a giant specially shaped screen that will have a spacecraft attached and that will go to space above the blurring effects of Earth's atmosphere and block out the starlight. Because the other methods we have to find planets aren't quite working for Earth. A true Earth twin, an Earth orbiting a sun-like star. Now our Earth is incredibly faint. It is ten billion times fainter than our sun. B billion. So we have to block out that starlight incredibly precisely so we can see the planet directly. Now this star shade right here is a very special shape. Because if we were to put a circular screen in space and block out a star, believe it or not, we wouldn't be blocking it out. It sounds crazy, but starlight can act like a wave. And it would bend around the outer edges of a circular screen, creating ripples. So it would be like dropping a petal in a pond. You'd get ripples. Ripples of light.

SPEAKER_02:

So for those listening on the audio version, Sarah's got a large metal disc. It almost looks like a paper sun pointing outward.

SPEAKER_03:

And it well large petals.

SPEAKER_02:

Large petals. It looks like a flower. Okay.

SPEAKER_03:

And what it is, it's called starshade. And the reason why it's so specially shaped is if it was just a circle and you block out a point source, you would get ripples. Like dropping a pebble in a pond, you get waves. These are like light waves. So with starshade, it would be like the light goes around the petals and interacts with itself to cancel itself out. What I showed you is a 1% scale model. 1%. So starshade would be a hundred times bigger.

SPEAKER_02:

Oh wow.

SPEAKER_03:

What isn't? Do you want to describe it for the listeners? That relates to the lensing I just showed you, that ginormous black structure.

SPEAKER_02:

Oh big. Yeah, and that's one of the petals.

SPEAKER_03:

One of the petals.

SPEAKER_02:

Yeah, there's a so it's like a long it is. It's a yeah, it's it's enormous. So you're building that now to launch.

SPEAKER_03:

Starshade has been developed by NASA and it's reached quite a level of maturity. But right now, we don't have a plan for it, doesn't have a funding plan to go forward right now, say.

SPEAKER_02:

So let's talk about missions. So you're deputy science director of TESS. What is TESS and what are some of the discoveries it's made for those who don't know it?

SPEAKER_03:

Sure. TESS is a transit mission. It launched in April 2018. TESS is basically four glorified telephoto lenses, about 10 centimeters in aperture. Each has a giant baffle. They're very custom made up. It's kind of a glorified telephoto lens.

SPEAKER_02:

Is there anything that's been a discovery that really surprised you that it came out with?

SPEAKER_03:

Sure. Let me just finish describing the mission. It has these four telephoto lenses and they're bolted on a platform, and the whole mission orbits Earth in a very highly inclined, highly elliptical orbit to have as much time in the dark away from Earth as possible. And it looks at a giant strip of the sky and covers tens of thousands of stars, a million stars every month. Tess has found, I mean, its goal was to find a lot of planets that could be followed up with the James Webb Space Telescope, transiting planets whose atmospheres we could try to observe. So in that regard, Tess has found a few hundred prime candidates for the James Webb Space Telescope to follow up. And it's definitely been succeeding at that goal. It's found a lot of things. I mean, I can't point to one specific thing that would be the next thing's like. But you know, it's found a combination of things. It's found many planets transiting small red dwarf stars that are easily accessible. Tess has found some planets transiting very, very young stars, stars as young as just a few million years old to help us understand planet formation. Because most mature systems are not millions, but they're billions of years old. And studied a lot of things outside of exoplanets.

SPEAKER_02:

The system that's closest to us, the Proxima Apha Centauri. Do you think that they'll find planets? I mean, do you think there's a there's a chance that there'll be something habitable for us?

SPEAKER_03:

Absolutely. In fact, our nearest star, Proxima Centauri, it's a red dwarf star, smaller than our sun by about half or a bit smaller. It has evidence for an Earth-mass planet in its habitable zone.

SPEAKER_02:

With a red dwarf, what would be different? So people that obviously we live here on Earth, if you were living on a red dwarf or say we tried to, what would be the light, the light spectrum would be different? But what would be different for somebody living there?

SPEAKER_03:

Well, one of the main things that's different is the planet has to be closer to the star because the stars give off very little energy. So for the planet to have the same temperatures our Earth has, it has to be much closer to the star. And the main result of proximity to the star is that the planet ends up in a favorable energy state where the planet rotates one time for every time it orbits. So that's complicated, but one day equals one year. And just like our moon has that with the Earth, due to tides over a long period of time, our moon slowed down until it shows the same face to Earth at all times. Because people don't think about it this way, but the moon is rotating one time for every time it orbits.

SPEAKER_02:

All times.

SPEAKER_03:

Yeah. So these exoplanets, they would be showing the same face to their star at all times. In other words, one side is always in day and one side is always in night.

SPEAKER_02:

Oh the temperature differences would be staggering.

SPEAKER_03:

So well, they might, but as long as the planet had an atmosphere, the atmosphere will recirculate all the energy. Just like here in New England, what happens on a cold day if you open your front door? All the hot air rushes out, the cold air rushes in. So if there's an atmosphere, we're not worried about that. But I want you to imagine for a moment being on one of these planets. Wouldn't that be weird? You either always have day or always night. The sun is always in the same place in the sky at all times.

SPEAKER_02:

Well, I think of Antarctica, the Arctic, your circadian rhythm. So the ability to sleep would be really tough on the system.

SPEAKER_03:

I mean, imagine that on vacation, we astronomers would go to the night side. We just see stars all the time.

SPEAKER_02:

Permanent study, yeah, to place to study.

SPEAKER_03:

Yeah, but there's one more bigger, much bigger problem. It's really that these M dwarf stars, they give off flares. Lots of flares, lots of high-energy particles. You know how here we get excited about the chance to see an aurora because our sun might have given off a little burst. Right. Well, this is much more significant and dangerous. In fact, here on Earth, we had an event in the 1850s called the Carrington event. Have you heard of that?

SPEAKER_02:

Very much so. I've studied a lot about it. Very familiar with the Carrington events, give it a shot. It essentially was a massive solar flare that hit Earth. And during that time, the only technology that really was of any sophisticated nature was the telegraph system. And it essentially fried anything electronic. And telegraph lines exploded, telegraph system it showed that with a massive solar flare, if we had something like that today, the disruption would be catastrophic.

SPEAKER_03:

Yeah, it's great. I mean, it was a flare, and it was a small part of our sun, came off our sun, a coronal mass ejection.

SPEAKER_02:

Yeah.

SPEAKER_03:

And it came hurtling towards Earth. And what people don't realize was that that part of our sun had a magnetic field embedded. And this goes back to physics, but when that magnetic field hit Earth's magnetic field, it induced a current. So literally, that breaking down your story, just to amplify it a bit, our Earth became electrified, literally. And yeah, people are really worried about that now because if it happened today, as you said, we have much more infrastructure that can be damaged here on Earth. It's called Aurora. And it's a book about how there's these disaster book scenarios.

SPEAKER_02:

Oh, yeah. No, I've read a lot of post-apocalyptic shots. Aurora. Yeah, so the Aurora is the book, the book of Rorro.

SPEAKER_03:

Yeah, it's a recent book by David Cope. Oh, yeah. I really like the book. And it's the scenario that this happens again because supposedly it's supposed to happen every 150 years.

SPEAKER_02:

Yeah.

SPEAKER_03:

And this book, disaster scenario, that it happens and what happens to our society. And it follows a couple of characters. One's a prepper who's prepared for disaster, and one is not at all prepared for anything. And it follows these two characters who have a somewhat intertwined story through the almost a pandemic without illness, but it's a pandemic of a different kind, basically. But anyway, yeah.

SPEAKER_02:

Go ahead.

SPEAKER_03:

Just racing ahead. Well, so here we are into this. But imagine living on a planet where it's a normal occurrence. Any one of these weekly or monthly. I imagine here in New England, in the old days, anyway, we had snow days. We get a dump of snow, everyone has to stay off the roads, work is canceled, school is canceled.

SPEAKER_01:

Right.

SPEAKER_03:

Same great day. I imagine in one of these worlds, you have a radiation day where a big burst comes through, it hits your planet. You've got to go into your special basement and stay there for a couple days till that energy disperses.

SPEAKER_02:

How do you really live on a planet like that? It makes me think about the solar radiation, the winds, things that we always talk about going to a place, but what about living in a place? Right.

SPEAKER_03:

Right, right, right. Yeah.

SPEAKER_02:

Yeah. I think that's a really interesting thing you bring up about exoplanets earlier on when I got to know you through your work on Venus. Can you dive deeper into your focus on the possibility of life in Venus's clouds? Like what could led you to explore that direction?

SPEAKER_03:

Definitely explain that. I was working on exoplanets, or am, coming up with a list of gases that might be a sign of life. Because in exoplanets, we're searching for life beyond Earth, not directly, but indirectly. Here on Earth, for example, we have oxygen that fills our atmosphere to 20% by volume. But without life, plants and photosynthetic bacteria, we would literally have no oxygen in our atmosphere. It's very reactive and needs to be continuously produced, or we would have none. A great sign of life elsewhere would be finding a gas that doesn't belong. We can't explain it away any other way in the context of environment without life. So I was part of a team that made a discovery, reported discovery of a gas on Venus, one that doesn't belong, that can't be made in any significant quantity by lightning, volcanoes, meteoric delivery, or anything. And this gas is called phosphine. Now, phosphine, very few people have heard of it because on Earth, it's only made by us humans as pesticides or found in some oxygen-free environments associated with life. Phosphorus doesn't go with hydrogen to make phosphine, it goes with oxygen to make phosphates. So this report became incredibly controversial the moment we released it. And people, it's still very controversial as to whether phosphine is present. If it is present, what it all means. And this was a problem, actually, a bit of a career crisis for me personally, only because that's my goal and others share the goal to find signs of life elsewhere. But it's really hard to believe. Anyhow, let's put phosphine aside for a moment, because phosphine reinvigorated the idea that there might be life in the Venus clouds, an idea that was started over half a century ago by Carl Sagan himself. And the concept is that the surface of Venus is too hot for life due to the massive carbon dioxide greenhouse atmosphere. But just like here on Earth, if you climb a mountain or go in an airplane, it gets colder and colder, right? As you go up. And so there's some big distance, 50 kilometers above the Venus surface where it's the right temperature for life. So that's how I got involved is through this phosphine discovery because it connected exoplanets to Venus. And then I and others started realizing just how interesting Venus is. And what we also realized is that although people have kept the idea of life in the clouds alive, no one did very much about it. And that's because the clouds aren't made of water. They're made of concentrated sulfuric acid, a very nasty chemical. Yeah.

SPEAKER_01:

Oh, yeah.

SPEAKER_03:

Wow. So nasty. And life has to persist in the clouds where the temperature is good. And we started doing experiments and we've showed, just to the complete astonishment of planetary scientists, who've assumed that concentrated sulfuric acid destroys anything interesting. But we found that, for example, our amino acids are stable in concentrated sulfuric acid, chemically modified, but stable. We have found a growing list of other biomolecules that are stable there. And we're doing these experiments of molecules in sulfuric acid to demonstrate, not that there is life on Venus, but that it's worth exploring. And so hand in hand with these laboratory experiments, we have designed a series of mission concepts, missions to go to Venus to search for signs of life.

SPEAKER_02:

If we found life in the atmosphere, like how do you think it'll change the approach to searching for life elsewhere? Because it's disrupting the status quo, which a lot of people how would that change the approach?

SPEAKER_03:

I think it will help people open up their minds. I mean, honestly, if we would do find life on Venus, it would just be so shocking. And I hope it will open up more people to be bold and to take risks and to just pursue things that others think is ridiculous. I mean, I think it really hopefully would motivate us to uh find the fastest, cheapest way to get to other bodies in our solar system. Because there's a lot of places where there could be life. They're just very hard to explore.

SPEAKER_02:

Yeah, I feel like there's two paths in the search. There's one, which is just search for life in general. Right. And then there's the search for an earth analog, like another humanity, if you will. I mean, we're trying that with other things that are close to us, but can you really sustain humanity for the long term? Not known at this point. But you've shared so many great uh stories. How close this is complete speculation. I mean, with the advanced in technology, with AI analyzing all the data, do you think we're close to finding our unearth analog?

SPEAKER_03:

We're very far from even though we have thousands of planets, yeah, an Earth around the sun, an Earth around a sun-like star is amongst the hardest to find. And so despite the thousands of planets and the huge, fascinating field of exoplanets, we're asking our instruments, our detectors to go so far we're not ready yet. And it's not just that the technology is so difficult to get ready. It's that the methods we have have hit a bit of a plateau because our sun has spots and has granulation from convection and noise in the star itself, our stars themselves, is preventing it. So AI is going to help us, but it's not going to be the magic bullet.

SPEAKER_02:

It was just more about processing data, the speed of which you can pull the things out to take a deeper look.

SPEAKER_03:

Right. I know. There's two things. I have this one for person I knew before who said computers make us dumb because you can throw all the processing power you want. And yes, that will definitely get you some gain. But let's imagine you have a factor of 10 to go, and throwing the computer at it gets you a factor of two, which is amazing. I mean, that's huge. You still have another factor of five. So I think we are working on both at once, using our brains to sort through the information content of all the data and getting the computers to help us for sure. But there's still quite a long way to go, but we're working it.

SPEAKER_02:

Well, my father refused to learn CAD for 30 some years, and he still can use the slide rules. He's in a traditional in that sense, sticking with the tried and true. Advancements in technology, do you think we still need to have that say the next 50 years, 100 years? What do we need to really have to detect life that on an exoplanet? Because it kinds of life.

SPEAKER_03:

Well, there's several things. We need to get our list of our targets, the sun-like stars that have Earth mass or earth-sized planets. That's one step. The second step is we have to do better with what we have. Then we have to go to space above the blurring effects of Earth's atmosphere to study the atmospheres of all these and to see which ones have water vapor indicative of water oceans, to see which have hopefully oxygen or ozone, a sign of life. And we need to then hammer away at those prime candidates to see what else is going on. But ultimately, the thaw scene on Venus lesson is that no one will ever fully believe just a gas far away and noisy data. No one will ever believe a gas on a planet far away with noisy data. We're going to need more. So we can see in our lifetimes, it would be a dream just to have a list of candidates. Hey, here's a planet with water oceans and oxygen. But we'll have to eventually the next step. So since you've given us 50 years, we'll at the same time as stretching our technology to even find this list of candidates, we'll have to start thinking of new paradigms in outer space. We have to find ways to, yeah, get a lot more data. And there are definitely some ideas out there that we need to pursue.

SPEAKER_02:

Yeah, because even solar sales or even the micro devices, I can't remember the name of them, that were going out, they're being starship. Yeah. Those they're going point one. Speed that'll take a hundred years. That's and they even just send back the day. It's this round trip of data. So it is, yeah. It's it's it's the lens of the long view and long view.

SPEAKER_03:

We have to get used to the long view because we're gonna have done the easy things, we'll have our lists of candidates. What can we invest in? What can we be patient with to really know for sure?

SPEAKER_02:

Oh, I I your memoir, which I read parts of it, is the smallest light in the universe.

SPEAKER_03:

So what made you write such a personal well the original thing that motivated me was a major personal tragedy that just was incredibly crushing. But thinking of this tragedy against the vastness of the universe, all the stars out there, the huge expanse, it was definitely hard to reconcile. So, on the whole, I wanted to tell my story. It started out that way because it's been an incredible journey. But it was also to capture this idea of hope and longing that we're all looking for something. Each one of us humans is on a journey of some kind. And although my journey is to find another earth, we all have something. And this title, The Smallest Lights in the Universe, has a double meaning. One is that we want to find the other earths to know that we're not alone. But at the same time, on our personal journeys, it's definitely an up and down. And sometimes you will hit rock bottom. You can't avoid it. And there you've got to hold on to whatever your tiny lights are, those little tiny beacons of hope that are going to get you out from the bottom of that canyon back to where you need to be to complete your journey.

SPEAKER_02:

That's wonderful advice. It made me think about your professor at MIT and you've taught a lot of young minds. Do you add that with other types of guidance?

SPEAKER_03:

I don't usually give advice because I try to stick to the professional. But once in a while there's a crisis, students commit suicide pretty much annually. And then I definitely get into it. And I definitely try to give the vibe or explain. I definitely try to help students. I mean, it's a mix. I try to stay professional, but where it's warranted, I definitely try to communicate. You know, you've got to focus on what matters. And it's usually not your grade.

SPEAKER_02:

To study in this field, what do you think are the most important qualities to be in this type of field? It's very exciting, but journey.

SPEAKER_03:

Well, the main advice I would give is to find something that you love doing, that you're also very good at, and that additionally you can get a job in. It's very hard to line all that up, but if you can, that's recipe to success.

SPEAKER_02:

That's great. I know we have to wrap up, but I'd love to have you on again. I think we can talk for another hour about this. How do people connect with your work? How do people find you?

SPEAKER_03:

Find me from my website, Sarah Seeger.com.space. And I'm also on Facebook, Instagram, LinkedIn, and a bunch of other social media platforms. You can just search for my name, Sarah Seeger.

SPEAKER_02:

Great. Sarah, thanks for your time and just uh great conversation. And uh we'll have to be wonderful talking to you.

SPEAKER_03:

I hope we can continue the conversation.

SPEAKER_02:

This is great. Thanks a lot. Have a have a have a great holiday. Thanks a lot.

SPEAKER_00:

Goodbye.

SPEAKER_02:

Bye.

SPEAKER_00:

Thanks for listening to the Think Forward Podcast. You can find us on all the major podcast platforms and at www.thinkforwardshow.com as well as on YouTube under Think Forward Show. See you next time.

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Steve Fisher

Host