Searching For Alien Life : TED Radio Hour Are we alone in the universe? Are we one of a crowd? This hour, we travel the cosmos with TED science curator David Biello, exploring where we are in the search for alien life.

Searching For Alien Life

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MANOUSH ZOMORODI, HOST:

David.

DAVID BIELLO: Yes.

ZOMORODI: Tell me about the Fermi paradox.

BIELLO: The Fermi paradox is, simply put, the question, why aren't the aliens here? Why haven't we seen them? With so many worlds out there and the seeming simplicity of life to develop, why haven't the aliens already visited us?

ZOMORODI: OK, but this question was first posed in 1950. That's kind of a while back. Do we still think that aliens may be out there?

BIELLO: I think we do.

ZOMORODI: It's the TED Radio Hour from NPR. I'm Manoush Zomorodi, and on today's show, where we are in the hunt for an answer to perhaps the biggest question about life in the universe - are we alone? TED's science curator, David Biello, takes us through the newest ideas and projects investigating if extraterrestrial life is out there, what it may look like, how we'll even know if we've found it. David, welcome back to the show.

BIELLO: Thank you for having me, Manoush.

ZOMORODI: OK. So, David, you have been on this show several times. And man, I am excited about this conversation that we're about to have. And we have to start this hour off by talking about the James Webb Space Telescope. This is the most powerful telescope ever launched into space. It was launched on December 25, 2021. You have kind of got an inside track on the scientists who built it.

BIELLO: That's right. I was lucky enough to work with John Mather on a TED Talk recently.

(SOUNDBITE OF TED TALK)

JOHN MATHER: When I was 6, my father told me that I was made out of tiny cells filled with chromosomes that would control my fate. I thought, that's amazing. There are so many mysterious things in there, and I want to know more. I read about Galileo and Darwin, and I became a scientist.

BIELLO: He is a Nobel Prize-winning physicist for building an earlier telescope - you know, no big deal, just a small prize you may have heard of. And when that research kind of came to a close, his bosses at NASA came to him and said, you know, what's next? How do you follow up a Nobel Prize-winning piece of equipment? And they proposed that, hey; we ought to send a telescope out to a Lagrange point, where it can just sort of sit in space and make these perfect observations.

ZOMORODI: What's a Lagrange point?

BIELLO: Lagrange points are these perfectly poised spots in space where Earth's gravity and the gravity of other bodies around us hold something in place so it never moves. And it's also a great place to stay very, very cold. And that's the key for James Webb because keeping it as cold as possible means that it can see in the infrared from the earliest moments of the universe.

(SOUNDBITE OF TED TALK)

MATHER: So the next thing is, what did we see?

ZOMORODI: I think by the time that John gave his TED Talk, they had tested the telescope, and they knew it was performing as they had hoped.

BIELLO: That's right. You can see in that TED Talk the images prepared of a pretty ordinary sector of space, some stars and whatnot, from an older telescope versus the focusing image of the James Webb.

(SOUNDBITE OF TED TALK)

MATHER: So the fuzzy picture is the Spitzer Space Telescope, launched in 2003. The sharp picture is the new Webb telescope. We were so thrilled that it worked. We got a nice, sharp image of the star, and we can calculate now the sensitivity of this object that if you were a bumblebee, a square centimeter object hovering at the distance of the moon from the Earth away from the telescope, we would be able to see you, both the sunlight you reflect and the heat you emit. So there are no bumblebees in space, but there's something out there that we don't know, and I'm so sure that we're going to get a great surprise from this telescope.

ZOMORODI: OK, whoa, that they could see you if you were a bumblebee on the moon. But surprises like what, David? Give us some ideas of what this telescope may show us in the years to come.

BIELLO: Well, so it's going to see with unprecedented clarity in both infrared and visible light, hopefully to answer some questions that we still have, like why is the universe expanding as it seems to be, and what determines that rate? So, you know, some pretty foundational questions, but it's also going to enable us to look at other planets or planetary-like bodies, whether that's here in our own solar system, peering more closely at some of the moons of other planets where we think there might be life, but also some of these many thousands of exoplanets that we're discovering every day that are orbiting distant stars. And the Webb will be able to peer at those in ever finer detail so that we can determine some of the characteristics of their atmospheres, which might give us some clues as to whether there is life on those planets or not.

ZOMORODI: In addition to exoplanets, which are just planets outside our solar system, the Webb telescope is also going to be looking at planets that are closer to us and moons like the ones circling Jupiter, specifically one called Titan.

(SOUNDBITE OF TED TALK)

ZIBI TURTLE: Picture a world with a variety of landforms. It has a dense atmosphere within which winds sweep across its surface and rain falls. It has mountains and plains, rivers, lakes and seas, sand dunes and some impact craters - sounds like Earth, right? This is Titan.

ZOMORODI: That's a very brief description of the moon Titan from another TED speaker, the wonderfully named Zibi Turtle.

BIELLO: Yes. Zibi is the scientific lead for the Dragonfly mission to Titan launching in just a few short years.

(SOUNDBITE OF TED TALK)

TURTLE: Indeed, Titan is one of several ocean worlds, moons in the cold outer solar system beyond the orbits of Mars in the asteroid belt with immense liquid water oceans beneath their surfaces. Titan's interior ocean may have more than 10 times as much liquid water as all of the Earth's rivers, lakes, seas and oceans combined. And at Titan, there are also exotic lakes and seas of liquid methane and ethane on the surface. Ocean worlds are some of the most fascinating places in the solar system, and we have only just begun to explore them.

ZOMORODI: The key thing about Titan is, because there's water, there could be life, right?

BIELLO: Yes. Well, there are two ways there could be life on Titan, as I understand it. The liquid ocean, the water trapped under some layers might harbor, let's say, deep life. And then on the surface, this kind of hydrocarbon world...

ZOMORODI: Hydrocarbons - that's basically the stuff in oil and gas.

BIELLO: That's right. This is literally something that you use for your barbecue gas grill. But it's a liquid on Titan, and it rains hydrocarbons. There's nothing to say that life on other planets couldn't use completely different substances than we do to have life.

ZOMORODI: But the most talked about thing about the Dragonfly probe besides what it is looking for is what it looks like because it is so cool, David. It's this giant helicopter drone, kind of like the one sent to Mars recently but much bigger. And it can do a lot more. So give us the basics.

BIELLO: Yeah. It's basically a larger version with some unique characteristics of that Mars helicopter, which was indeed the first human-built aerial vehicle to fly on another world, which is a pretty cool thing. But...

ZOMORODI: Yeah.

BIELLO: Dragonfly's going to be even cooler because the world it's going to fly on has low gravity. So you know how you've seen probably video of the astronauts bouncing around on the moon. It's a kind of similar situation out there - makes it a little easier to fly. But in addition to that, it has a dense atmosphere, which also makes it easier to fly. So Dragonfly's going to be tooling around the whole planet, checking out these hydrocarbon lakes, hopefully not running into too much severe hydrocarbon weather and hopefully, you know, just sending back reams of data of what this world is like. And in some of that data, maybe we'll see that there are signs of life.

(SOUNDBITE OF TED TALK)

TURTLE: In many ways, Titan is the closest known analog we have to the early Earth, the Earth before life developed here. From Cassini-Huygens measurements, we know that the ingredients for life, at least life as we know it, have existed on Titan. And Dragonfly will be fully immersed within this alien environment, looking for compounds similar to those that might have supported the development of life here on Earth and teaching us about the habitability of other worlds. Habitability is a fascinating concept. What's necessary to make an environment suitable to host life, whether life as we know it here on Earth or perhaps exotic life that is developed under very different conditions?

ZOMORODI: David, can we talk about the point that Zibi is making there? I mean, not to be a Debbie Downer, but we have never seen alien life, or at least not to our knowledge. So how will we know if what we're seeing even qualifies as life?

BIELLO: It's a great question. And honestly, we won't know until we see it. And there will be a robust debate on whether we have seen it. You might recall that there have been such debates already. Sometimes we've picked up methane on Mars, and people have been like, it's life. And other people have been like, no, it's not. There was a meteorite from Mars that I think was found in Antarctica. And some folks said, hey; there are signs of life in this meteorite. And other folks were like, no, that's nuts. And usually, it's not aliens, but one day, perhaps, it will be aliens.

And the trick here is it might be easy. The aliens might look a lot like us. It might be - I'm not talking about little green men. I'm talking about bacteria. They might be, you know, cells with DNA and all the things that we recognize from life on Earth. Or life on other worlds might make it hard for us. It might be much more exotic. It might be harder for us to detect, in which case we'd be looking for signs of processes that are organic versus inorganic, meaning in the same way that there is oxygen in Earth's atmosphere solely because of photosynthesis on Earth, that oxygen would not last.

If photosynthesis shut off tomorrow, the oxygen would leave pretty quickly, and any aliens who are watching would know that that form of life on Earth had gone away. Without life, no oxygen. That's how we might find aliens who are very different from us via these trace evanescent gases in the atmosphere that say, hey; there's something strange and unique going on here.

ZOMORODI: All right, strange and unique being the key terms for a humanities major. In a minute, TED's science curator and I will be back to talk about the potential for alien neighbors next door - and, no, not on Mars but on Venus. You're not going anywhere, right, David?

BIELLO: I won't leave you.

ZOMORODI: OK, good. You're listening to the TED Radio Hour from NPR. Stay with us.

(SOUNDBITE OF MUSIC)

ZOMORODI: It's the TED Radio Hour from NPR. I'm Manoush Zomorodi. On the show today, the search for alien life. And with me is David Biello, TED's science curator. David, hello again.

BIELLO: Hello.

ZOMORODI: So, so far, we have talked about the Webb telescope and Dragonfly, a mission to suss out Jupiter's moon for any life forms. But as we mentioned, these scientists are unlikely to come across little green people, but they might find certain molecules. And that brings us to our next speaker.

BIELLO: Yes. I had the unique privilege of working with a quantum astrochemist - not everybody can say that.

ZOMORODI: No.

BIELLO: Her name is Clara Sousa-Silva, and she is looking for signs of life on these exoplanet atmospheres and, in particular, was focused on a stinky little molecule called phosphine.

ZOMORODI: OK, so here's Clara Sousa-Silva on the TED stage.

(SOUNDBITE OF TED TALK)

CLARA SOUSA-SILVA: I'm a quantum astrochemist, which means I study the quantum interactions between molecules and light in space. We can't see these molecules or even the planets they're on. When life from a star goes through an alien atmosphere, each molecule within it leaves a unique fingerprint in the star light that I can see from here. And I look for the fingerprints of molecules that could be associated with life, or biosignatures.

In the context of Earth, oxygen is a wonderful biosignature, but oxygen is not that hard to make. So my specialty is to look for unusual molecules that have fewer false positives for life because they're so difficult to make that they're rarely made spontaneously. And my favorite of those unusual molecules is phosphine.

ZOMORODI: Apologies, David. I have never heard of phosphine. What is phosphine? Why is it important?

BIELLO: So phosphine is just a unstable molecule incorporating phosphorus and other elements. And it's not something that you're likely to find produced by - I don't know - a lightning strike. So it's important as a potential signal that something strange and unique must be going on in order for that phosphine to be produced. And that strange and unique thing that might be going on is life.

ZOMORODI: And that's what she found - right? - those clues.

BIELLO: That's right.

(SOUNDBITE OF TED TALK)

SOUSA-SILVA: An astronomer, Jane Greaves, reached out to me asking for help with interpreting a telescope signal, then months later, another signal that seemed to indicate that phosphine might be present, not on a distant planet but right next door on the clouds of Venus. So did we do it? Did we find life beyond Earth? We don't know. These Venus observations were noisy and preliminary, so we still need to confirm without a doubt that the signal is real. And if it is, we need to make sure it's not another molecule mimicking phosphine's fingerprint. And if it is unambiguously phosphine, we still need to figure out what or who is making it.

ZOMORODI: OK, so what do they currently think now? They've seen these signs, but do they think phosphine is a sign of life on Venus?

BIELLO: Well, much like the argument around the methane on Mars, other astronomers have looked at Venus in similar fashion and think that maybe it's not phosphine, that maybe what we're seeing is just the sulfur dioxide that we would expect to see in these highly acidic clouds of Venus. That said, this is the perfect opportunity to stress test such a finding. If we found something on an exoplanet tens of light years away, we cannot go there to double check the math...

ZOMORODI: Right.

BIELLO: ...Or the detection. We can't go there. But, Venus, we can go there. We can send a probe to see if there is phosphine in the clouds of Venus. And if there is, well, then maybe that probe can look for the life that may have created it.

(SOUNDBITE OF TED TALK)

SOUSA-SILVA: As much as I love phosphine, I don't think that's how we'll find life. The detection of life will likely not come from a single molecule, no matter how special it is. We'll have to detect a whole biosphere producing a complex network of gases that together form a message that reads we're alive. This will not be the last time that we have the discovery of a biosignature on a potentially habitable planet. And next time, we won't be able to just go there and check.

So my biggest concern is not that we will fail to find a habitable planet in our lifetimes. My biggest concern is that we'll point our very expensive telescopes directly at an inhabited planet and just not know we did it. But I am determined to not miss life. So, yes, I'll keep looking for the strange and scary biosignatures like phosphine. But crucially, I will look for all the molecules that can together paint a holistic picture of a biosphere - all of this so that one day, we'll know life when we see it.

ZOMORODI: I mean, David, do arguments and debates about what is or isn't an indicator of life in the universe happen all the time? Like, it's methane. It's phosphine. It's sulfur. Like, is that what we're talking about here? I mean, I think it's hard for those of us who maybe only took chemistry in high school - maybe college...

BIELLO: (Laughter).

ZOMORODI: ...To understand that that's what it comes down to.

BIELLO: Yeah, well, actually, these are new debates. We did not have the capacity to detect potential signs of life, these biosignatures, even 50 years ago. So these debates are a new thing, and they are becoming more relevant thanks to these new, powerful tools, like the James Webb Space Telescope or the missions that will go to Venus and Titan and elsewhere in our solar system. We stand on the cusp of, for the first time, being able to see a biosignature and then go check it out and determine, OK, is that really a sign of life, or is it just another phantom in the wind?

ZOMORODI: (Laughter) Phantom in the wind.

BIELLO: (Laughter).

ZOMORODI: OK, so we've been talking about humans searching for alien life, but I want to switch tack now and ask, you know, what if the aliens are looking for us? So, David, let's talk about the first-detected interstellar visitor that our solar system ever got. It happened in 2017. It's an intriguing story from astrobiologist and astronomer Karen Meech. And it's not just a little molecule. This is a story about something far larger.

BIELLO: Yeah, a very weird rock or chunk of ice or something else flew into the solar system at high speed in 2017, and Karen and her colleagues were lucky enough to catch it with some ground-based telescopes.

ZOMORODI: To be clear, when you say catch it, you mean take photographs?

BIELLO: Correct. To see it. Yes, that's right, not reach out and touch it and catch it and bring it in...

ZOMORODI: (Laughter).

BIELLO: ...But to visualize it. But this is the first time we had ever caught such an interstellar object moving through our solar system. So it was, again, a strange and unique observation, although perhaps these things aren't that rare after all.

ZOMORODI: And it was given the name - I hope I say this right - Oumuamua, which essentially means, in Hawaiian, scout or messenger.

BIELLO: That's right. Because of its status as the first interstellar visitor, it was given that name and, in particular, a name from the Hawaiian language because it was telescopes in Hawaii that first detected it.

ZOMORODI: OK, here's Karen Meech in 2018 giving her talk about the discovery.

(SOUNDBITE OF TED TALK)

KAREN MEECH: NASA's been expecting to see an interstellar comet pass through the solar system since the 1970s. But until now, we'd never seen anything. Our own solar system is huge, so even getting a package from the nearest star system 4.4 light-years away would take over 50,000 years. So this is a really big deal. The interstellar visitor entered our solar system from above the plain of the planets, coming from the direction of the constellation Lyra, and it passed closest to the sun on September 9, 2017, passing inside the orbit of Mercury. Now, this isn't a particularly close approach or unusual distance. It's just much easier to see objects close by. On October 14, before we discovered it, it made its closest approach to the Earth, within about 15 million miles. This is really close by astronomical standards.

ZOMORODI: OK, it's like out of a movie, David - an asteroid or comet coming for us. But scientists are always monitoring anything out of the ordinary. How do they do that, usually?

BIELLO: Yeah. I mean, we're just scanning the skies with all these different telescopes. And I should add, it's not just scientists; it's also amateur enthusiasts who oftentimes do discover a new asteroid or comet and get the chance to name it. So you, too, could discover an interstellar object if you got really, really, really lucky. But as that clip intimates, we didn't see this until it was already on its way out of the solar system, and we were only able to sort of backtrack its path after the fact, after we had seen it reflected in the sunlight. And that's how we knew it had come from interstellar space, and that's also how we knew that it was back on its way out into interstellar space.

ZOMORODI: So did they ever find out for sure that Oumuamua was a comet or asteroid?

BIELLO: We still don't know what it was or is. Again, this is the first interstellar object that we've ever observed, an n of 1 as the scientists would say. And an n of 1 doesn't tell you that much. That said, there are likely to be many more of these now that we know what to look for. We might be able to figure out or gain a better understanding of what these objects are and why they're here, whether it's aliens sending a probe, the least likely explanation.

ZOMORODI: But that is one of the theories.

BIELLO: That is definitely one of the theories. It's just the least-likely one - to, you know, a piece of space junk, by which I mean not the remnants of an alien spaceship but, like, the remnants of planetary formation and other processes that go on out there all the time in the universe and fling these bits of matter all around the universe.

ZOMORODI: OK, so we still don't know exactly what Oumuamua is, but just looking at drawings based on the data, some people think it looks like a giant cigar. To me, it looks like a giant door wedge hurling itself through space.

BIELLO: Right, like a splinter of an asteroid.

ZOMORODI: Yes.

BIELLO: We think it was that shape. It actually could have been several other shapes as well. It all comes down to the way that it reflected the light and the way that the material was coming off of it.

(SOUNDBITE OF TED TALK)

MEECH: It started faint, and then it got brighter, fainter, brighter and fainter again as sunlight is reflected off of four sides of an oblong object. The extreme brightness change led us to an unbelievable conclusion about its shape. Oumuamua is apparently very long and narrow, with an axis ratio of about 10 to 1. Assuming it's dark, this means it's about half a mile long. Nothing else in our solar system looks like this.

Oumuamua was varying in brightness every 7.34 hours - or so we thought. As more data started to come in from other teams, they were reporting different numbers. Why is it the more we learn about something, the harder it gets to interpret? Well, it turns out that Oumuamua is not rotating in a simple way; it's wobbling like a top. So while it is rotating around its short axis, it's also rolling around the long axis and nodding up and down. This very energetic, excited motion is almost certainly the result of it being violently tossed out of its home solar system. Now, how we interpret the shape from its brightness depends very critically on how it's spinning. So now we have to rethink what it may look like. We think that Oumuamua may be more of a flattened oval.

BIELLO: So, really, more mysteries than answers at this point. And the hope is that we'll see other interstellar visitors so we can begin to solve some of those mysteries. But, yeah, it could be a UFO. We don't know.

ZOMORODI: OK. Can we - I feel as though we need to tackle this question. We need to talk about just regular people's fascination with UFOs. I am a little disappointed that Oumuamua didn't land on our planet. I would have loved to have seen it. But people love to talk about UFO sightings, right?

BIELLO: Oh, yeah. I mean, strange and unusual doings in the sky - what's not to love? That has been around for years, some of which can probably be attributed to, you know, the development of top-secret military aircraft...

ZOMORODI: Right.

BIELLO: ...And some of which can't be explained, at least not in any way that we publicly know of. You know, I myself hope one day to see a UFO, but hasn't happened yet.

ZOMORODI: I mean, I feel like when I was growing up, it was mostly about conspiracy theories.

BIELLO: (Laughter).

ZOMORODI: But now it's become more mainstream in some ways.

(SOUNDBITE OF ARCHIVED RECORDING)

RONALD MOULTRIE: It's a privilege to be here with you today to address your questions regarding unidentified aerial phenomena, or UAP.

ZOMORODI: I mean, in May 2022, for the first time in, like, I think over 50 years, the U.S. Congress had hearings on UFOs. They call them UAPs.

BIELLO: Yeah, unidentified aerial phenomena. And, again, this gets into definitions. So there are a lot of unidentified flying objects out there. All that means is we saw something in the sky. It was flying. And we don't know what it is. Ninety-nine times out of 100, or probably many more nines and many more zeros...

ZOMORODI: (Laughter).

BIELLO: ...It's not going to be aliens - sad but true.

ZOMORODI: OK, but so then, why has NASA recently weighed in on UFOs, or UAPs, as well? They said that they're going to be opening a new study into them. What are they doing?

BIELLO: Well, it's a mystery. In the same way that Oumuamua continues to present mysteries, these unidentified flying objects are mysterious to our best scientists and defense planners, it appears. And we want to know. If it is aliens, we want to know that. If it is some secret flying object from a foreign adversary, say, we want to know that, too. Identifying the unidentified flying objects is the goal of both the Department of Defense and NASA and, really, anybody else studying these phenomena.

ZOMORODI: But can you explain, though? - because I thought that NASA was always searching for alien life. Didn't the SETI Institute come out of NASA?

BIELLO: So SETI is the search for extraterrestrial intelligence, and that's a very different approach than studying UFOs. It's an approach of kind of looking out into the universe and seeing if we can see things that might show signs of life, show signs of intelligence and also sending a message that might be picked up by other intelligent life out there in the universe in a very purposeful way. We are, of course, doing that inadvertently with our radio broadcast here.

ZOMORODI: Right - noisy Earth.

BIELLO: Yes, noisy Earth - exactly. So if there are aliens listening, hello, first of all.

ZOMORODI: (Laughter).

BIELLO: And second of all, please come visit. But, you know, SETI was a much more purposeful approach to this question and attempted to identify both likely candidates and then to send messages to those likely candidates.

ZOMORODI: All right. You just said hello to the aliens, but when we come back, what if, instead of looking for aliens in the universe, we put life out there ourselves? This is a wild idea, David.

BIELLO: Yeah, it is.

ZOMORODI: (Laughter) You're listening to the TED Radio Hour from NPR. I'm Manoush Zomorodi, and TED's science curator, David Biello, and I will be right back.

(SOUNDBITE OF MUSIC)

ZOMORODI: It's the TED Radio Hour from NPR. I'm Manoush Zomorodi, and sharing the hour with me is TED's science curator, David Biello. David, you're still here. Thank you.

BIELLO: I am.

ZOMORODI: We are talking about searching for alien life. What's your philosophy? Like, why do you think we're so desperate to know if something else is out there?

BIELLO: I mean, it's such a fundamental question. Are we alone in the universe? Is humanity special and unique because we're the only intelligent life in all this vastness of space? Are we one of a crowd? And if we are one of a crowd, can we hang out together? Can we talk? Can we learn from each other? My hope is that we're not alone, that there is alien life out there. The only problem is, I'm not entirely convinced that it will be intelligent life.

ZOMORODI: OK, yeah, it could be - what? - a virus or a molecule.

BIELLO: Well, maybe not a molecule, but certainly a cell, a bacteria. So if we found a small, self-replicating life with a memory on Titan, that, for me, would constitute alien life. And that for me would answer, are we alone? Now, other folks are really focused on that intelligence bit...

ZOMORODI: Right.

BIELLO: ...And I think that's a little bit harder.

ZOMORODI: Yeah. And that, really, is bringing me to the next speaker, with whom you worked, physicist and writer Stephen Webb, who we should say has no relation to the Webb telescope. We've talked about how there could possibly be life, but Stephen is saying, yeah, but there's also a lot of reasons why there cannot be life out in the universe because there are hurdles that are just too large to overcome.

(SOUNDBITE OF TED TALK)

STEPHEN WEBB: So where is everybody? It's a puzzle because we do expect these civilizations to exist, don't we? After all, there could be a trillion planets in the galaxy, maybe more. You don't need any special knowledge to consider this question, and I've explored it with lots of people over the years, and I've found they often frame their thinking in terms of the barriers that would need to be cleared if a planet is to host a communicative civilization.

BIELLO: Yeah, he's really noting that the math is against us, and it's because, you know, there aren't that many habitable planets out there as far as we can tell.

(SOUNDBITE OF TED TALK)

WEBB: We need a terrestrial planet in that just-right Goldilocks zone where water flows as a liquid.

BIELLO: We've got a catalog of thousands of exoplanets, and most of them seem very inhospitable for cellular life, let alone, you know, advanced industrial civilizations with intelligence.

(SOUNDBITE OF TED TALK)

WEBB: Abiogenesis, the creation of life from nonlife - that's the second barrier. The basic building blocks of life aren't unique to Earth. Amino acids have been found in comets, complex organic molecules in interstellar dust clouds, water in exoplanetary systems. The ingredients are there. We just don't know how they combine to create life. And presumably, there'll be worlds on which life doesn't start. The development of technological civilization is a third barrier.

BIELLO: This intelligent life would have to persist long enough to develop an advanced industrial civilization capable of sending radio signals across the universe, or rockets or whatever else. And that's perhaps the most distressing hurdle. Space is really, really big. Getting anything across it is really, really hard. And so the chances of us ever being in communication with this potential other intelligent alien life is just vanishingly small.

ZOMORODI: OK, and so here is Stephen Webb and his conclusion.

(SOUNDBITE OF TED TALK)

WEBB: There's an obvious answer. We're alone. It's just us. Depressing, right? I'm arguing the exact opposite. For me, the silence of the universe is shouting, we're the creatures who got lucky. All barriers are behind us. We're the only species that's cleared them, the only species capable of determining its own destiny. And if we learn to appreciate how special our planet is, how important it is to look after our home and to find others, how incredibly fortunate we all are simply to be aware of the universe, which humanity might survive for a while, and all those amazing things we dreamed aliens might have done in the past, that could be our future.

ZOMORODI: All right. In the end, it's hopeful. We're the creatures who got lucky, Stephen says.

BIELLO: Yeah.

ZOMORODI: How do you think, David, accepting that we are indeed alone in the universe would change science, would change the work that you do with researchers?

BIELLO: I mean, honestly, I'm not sure that it would change all that much because as far as we know right now, we are alone. The only thing that might change if we definitively knew that we were alone is we might stop searching. Things like SETI might no longer happen. That said, I don't know how we would ever definitively know that we are alone in the universe. There's always going to be that part of the universe that's just out of our reach, just past what we can see, just past what we can hear. And there's nothing to say that, oh, that's where the aliens are, and we just can't see them.

ZOMORODI: All right, maybe we're alone. Maybe we're not. But I want to bring us to our last speaker, who - whoa. She has quite an extraordinary concept. Dr. Betul Kacar - I saw her give her talk in 2022 which is called "We Could Kickstart Life On Another Planet. Should We?" It kind of blew my mind. Tell me about Betul.

BIELLO: Yeah. So she was presenting a pretty wild idea, and she studies the origins of life on Earth to better understand what might promote the origins of life on another world.

ZOMORODI: Here's Betul in 2021, describing her research from the TED stage.

(SOUNDBITE OF TED TALK)

BETUL KACAR: In the past 10 years, there has been remarkable innovations in our understanding of origin of life. I lead a research laboratory, and we are using statistics and mathematical models and evolutionary systems and infer the sequences of ancient DNA that existed billions of years ago. We then synthesize these ancient DNA molecules and engineer them inside organisms. For the first time, we are able to activate molecules that existed billions of years ago to understand and capture what happened back then. We also simulate ancient environments in the lab to understand the ingredients by creating them from water, air and rocks. This may mean that we would be able to obtain the recipe of life, if you will, and having this recipe would enable us to connect the dots between these two states of living and nonliving.

ZOMORODI: OK, so she thinks that she can recreate the recipe for life from billions of years ago.

BIELLO: That's it. Yes - kind of a chemistry starter kit for life.

ZOMORODI: OK, well, that's extraordinary in and of itself. But then she wants to do what?

BIELLO: Well, Betul also takes it a step further by saying, if we are alone, if Stephen Webb is right and we're alone in the universe, do we have a responsibility, a duty, even, to kickstart life on other worlds, to spread life throughout the universe? Is that our mission, if you will, in life? Let's say we sent it to another solar system out there called TRAPPIST-1. It's a colder star, but the planets are closer in, and they might be the perfect places to provide habitability.

And so once that package arrived, perhaps it could contribute some of the ancient chemistry that was required to kickstart life here on Earth, and then that life would take root on TRAPPIST-1. And hundreds of millions, billions of years later, perhaps, there would be a flourishing biosphere there. Perhaps humans would be long gone, but this life that we had seeded throughout the universe would go on, and perhaps some of that life would persist long enough for an intelligent, advanced alien life to develop.

ZOMORODI: OK. I want to just get a little more clarity. She's suggesting we seed life across the galaxy like a farmer planting crops on a farm? Am I understanding this correctly?

BIELLO: Not quite.

ZOMORODI: OK.

BIELLO: Imagine that the farmer is able to sow the preconditions that allow for the development of the microbes that keep the soil alive and enable the crops to grow and thrive and then ultimately enable the crops to even exist.

(SOUNDBITE OF TED TALK)

KACAR: This would not be seeding them with Earth life. This wouldn't be engineering an Earth organism and pre-adapt them and precondition them in a way that they exist and survive in this other planetary body. This wouldn't be terraforming, altering the environment of this other planet so that whatever we ship there makes it. This would be about empowering and not colonizing these environments. This would be about letting them explore their own unique chemistry, to express their own unique reactions by providing them the missing ingredients.

BIELLO: So it's not so much sending Earth life out into the universe to colonize the galaxy and beyond, so much as...

ZOMORODI: Sending the fertilizer.

BIELLO: Yeah, sending the conditions that allow those planets to fulfill their destiny, perhaps, if that's not being too grandiose, to fulfill their destiny as homes for alien life, something completely different than what we have here on Earth, but just a little bit of extra chemistry to get that process going. The trick is, you know, it's a fine line between life and nonlife. You know, is a virus alive? By some definitions, you might be able to argue yes.

ZOMORODI: OK, hang on. Hang on. Hang on. Like, the basic premise of sending and seeding lifelike conditions elsewhere - is this a controversial idea?

BIELLO: Oh, 100% it's a controversial idea. You know, this is like tampering with any other natural process. Do we have the right to tamper with TRAPPIST-1? Do we have the right to send something there to interfere with what would have happened anyway? I would say yes, we do, but others would argue strenuously against that. I guess the argument that Betul is making is that it's not so much a matter of rights as, if we are alone, then perhaps we have an obligation to spread life throughout the universe. Perhaps that is our destiny.

(SOUNDBITE OF TED TALK)

KACAR: This is an extraordinary proposition, and it brings up extraordinary dilemma about what it means to be alive. Does life, as a chemical system capable of formulating and in some cases answering questions about its own existence, have a responsibility or should have a prohibition against sponsoring more life across the universe? And what is the ethical difference? And is there any ethical difference between spreading a particular Earth life versus spreading a potential of life across the galaxy? And where does this difference lie? Should we do it just because we can?

ZOMORODI: Clearly, in science, this is not a new question. It's at the heart of science fiction, like "Jurassic Park," CRISPR, gene-editing tools. We can now edit our DNA, but we are just starting to figure out the ethics of when and if we should. Where are we in this conversation about seeding life or the preemptive conditions for life out there in the universe, David?

BIELLO: I mean, for me, personally, I think we better double check, triple check, quadruple check that there isn't already life there before we go about sending life starter kit throughout the universe. It would be a bit of a mean move if there already was life on Titan, but we sent this starter kit to jumpstart some other form of life that then competed with whatever was already there. That's not nice. That's not what good neighbors do.

ZOMORODI: Not nice.

BIELLO: That's not what good neighbors do. So yes, I think the search for life must go on, and then if, and only if, we can completely rule out any other forms of life on that other planetary body, well, then, maybe it is OK for humans to go there or for Earth microbes to go there or, like Betul is arguing, for the starter kit of life to go there so that this planet can kind of express its own unique form of life.

ZOMORODI: All right. Let's push back because I know that there are some people who are likely thinking, you know, why are we spending so much time and money on any of this research when our world, our Earth, is in jeopardy of surviving? Period.

BIELLO: Yeah. This is the ultimate space versus Earth question, and the simplest answer to that is there are lessons to be learned in kind of the cold, unforgiving vastness of space that have real application back down here on Earth. You heard it in some of these talks. If we are alone, maybe that makes Earth slightly more special and we start to treat it that way. If we do see things on other worlds, maybe that teaches us how unique and special life on Earth here is, and we do more to protect it.

The most important thing to remember is that we're all on this particular Earth spaceship together, and we need to bring as many of our fellow travelers along with us into the future as is humanly possible. Our chances of stumbling upon that one radio signal that proves that there's intelligent life out there in the universe are just vanishingly small. But, you know, never tell me the odds, right? Some people are going to go out there and search anyway, and I hope they find something someday. I really do. I think - I hope we're not alone.

ZOMORODI: Oh, David Biello, thank you so much for being with us here. And it means a lot to understand our place in the universe. It is the ultimate question. So thank you.

BIELLO: I agree. Thank you, Manoush. It's always a pleasure to be here.

ZOMORODI: And thank you for listening to our show this week about the search for alien life. To see all the talks that David and I discussed and hundreds more TED Talks, check out ted.com or the TED app. This episode was produced by Matthew Cloutier and James Delahoussaye. It was edited by Katie Simon. Our production staff at NPR also includes Sanaz Meshkinpour, Rachel Faulkner, Katie Monteleone, Fiona Geiran, Rommel Wood and Katherine Sypher. Our theme music was written by Ramtin Arablouei. Our partners at TED are Chris Anderson, Colin Helms, Anna Phelan, Michelle Quint, Sammy Case and Daniella Balarezo. I'm Manoush Zomorodi, and you've been listening to the TED Radio Hour from NPR.

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