Lab-made life possible very soon – Nobel Prize-winning astronomer

SS: Alright, so you study exoplanets. And that's what brought you the Nobel Prize. And the closest exoplanet known to this day is 9000 times further away from Earth than Neptune. How do you search for something that is just so far away?

DQ: Well, it's difficult to find a planet, because it's very close to a very bright object that is the star. So we have to do tricks, we’re using what we call indirect effect of the planet on the star. So there are two main effects that you can use. The first one is, when the planet is orbiting the star, the star is moving a little bit, it’s a tiny motion. But if you have a very sensitive machine to measure these motions, if you use, for example, the change of the speed of the star, you can detect the planet that way. The other way is, if you got lucky, and the planet is just crossing the line of sight between you and the star, it makes for a brief moment a slight shadow, we call that transit, and we see a slight decrease of the light of the star. And we use that to get the size of the planet. Essentially, all the planets that have been found, have been detected by these two techniques so far.

SS: We hear a lot during the last decade that our galaxy might be teeming with trillions of Earth-like planets, yet finding them looks like searching for a needle in a haystack as they’re insanely far away and actually, they don't produce light like stars. So what makes your fellow scientists so sure there must indeed be many of them out there? How do you know?

DQ: Oh, that's pretty sure. When you detect these two specific signals, there is no way to do that but having a planet. So we’re absolutely sure there are planets orbiting the stars. But what is interesting about your questions is, some time ago, we found that all the planets would look like our own system with a small planet next to it, like the Earth, and then the giant planet far away. Actually, we have realised that is a bit more complicated than that. We have a lot of planets which are orbiting stars way closer, closer than the orbit of Mercury. And that was a big shock when we found the first one, that was a planet like our own Jupiter, really a big planet full of gas. Jupiter is very far away, it takes more than 10 years for Jupiter to orbit the Sun, while the planet like Jupiter we found 25 years ago, took only four days to go around the star, so that means the planet is very close. So that was really the big surprise. And we have learned since then, that our own system is maybe one amongst many, that's not the archetype, that's not the standard way to have a planet. And that was a shock because everybody was expecting planets to look all the same. So we have, you’re right, a lot of stars. But we also have a lot of very different kinds of planets.

SS: Now, there are thousands of exoplanets out there and to find a truly habitable one scientists look if they have an atmosphere, liquid water, if they're rocky. I understand the first two, but can you explain why a planet needs to be rocky to be seen as potentially habitable? It's not like the variety of landscape that makes life possible, is it?

DQ: Yeah, that's correct. I think you're perfectly right. I think we don't know exactly what we need when you're talking about life. Habitability is a very specific definition with something coming from the fact that when you have a rocky planet, it defines the possibility for that rocky planet to have liquid water. That said, the only thing that describes habitability. But you could imagine planets that are different from this one that could still be inhabited. So these are completely different stories. Habitability is sometimes a bit confusing because it comes just by the definitions of liquid water. Now, if you look in the Solar System, our own system, of course, we have Mars, we have Venus, we have the Earth. Actually, these three planets are all within the habitability. Well, it's not the case because Mars has lost most of its atmosphere, Venus has a very thick acidic atmosphere. So it's way beyond habitability, but technically speaking, they could be habitable. Now, we also have some satellite of a giant planet that has a crust of ice. And we know that under it, there is liquid water. So we don't really know whether there’s a chance that life has started there. And that's the beauty of the problem. So I think you're right by saying that being rocky is not an absolute prerequisite for a planet’s habitability. But it’s simple for astronomers: when you think about a rocky planet, and there are plenty of rocky planets, we can just ask ourselves, whether there is an atmosphere on this planet, and we can try to understand what this atmosphere is made of. And that's the kind of program that we will be doing in the next 20 years.

SS: To find life on some exoplanet, not in theory but in practice, we have to send a robot there at least to collect soil samples, etc., which doesn't seem to happen anytime soon. Will the search for a habitable Earth-like planet remain solely on paper until the technology is in place, or are there ways to find out sooner?

DQ: What is going to happen is there are three ways to look for life and each is telling you something about life. The first way is to just look at life as we know it. The only life we know is the life we have on Earth. There is only one single life on Earth, so people can study the chemistry of life on Earth and can look to understand the origins of life. We have not really understood that yet. But you can look for that on other planets of the Solar System. So that's the first way to do that, you have real chemistry and real objects. We can think about bringing rocks from Mars, we can think about bringing rocks from Venus, it's possible to study whether you find some ancient sign of life there or actual sign of life in the system. So that is something you can do as well. The problem there is you may find the same kind of life we have on Earth. Now, when you're talking about planets around other stars, that's true to say that it's very unlikely we'll go there very soon because it's tremendously difficult. And we may even never be able to reach that place. But we can remotely study the atmosphere of these planets, and we may find something strange. Well, of course, I mean, having one planet with a strange atmosphere will not tell you the real story. So I used to describe this as like doing a painting. You do a big painting but when you do a little bit of a detail of one painting, you don't understand the global shape of the painting. So one planet will tell you one part of the story. But the big difference with studying few planets in the Solar System, we have potentially a lot of planets we can study, and a lot of planets are slightly different and have a slightly different composition. So, we will do a kind of a global picture. Each of them will not tell you really anything. But the hope is when we will have studied thousands of atmospheres, it’s like a big painting, then we will start seeing the big picture. And we will combine what we have learned with a detailed study on specific pieces of rocks, like you said, from the material coming from other planets of our own system.

SS: So even if someone finds a perfect exoplanet, it will still be so far away from us that travelling to it will be impossible in any practical way, travelling from it I think is just impossible. So why all this fuss? What is the use of finding it? Okay, we’ve found a planet but we can't go there and we can't come from there.

DQ: Well, I used to say there are three profound questions that everybody keeps asking and the humankind has tried to answer almost since the beginning. The first one is the origins or the nature of the matter of the world. Where are we? What are things around us? That's one big question and it collects a lot of sciences. The second one is the origin and the nature of life. It remains a profound mystery. Matter at some point can become alive, and that's quite amazing. So this is the second question. The third one is consciousness. At some point, you build up consciousness. Well, when you're dealing with life on the planet, actually, you are addressing one and maybe two of these questions together to try to understand. And the only way to understand is to look and to study. That's what we're doing. What we're going to find – I don't know. My understanding is life is some kind of chemistry that went a little bit on its own, and to control of itself is able to produce by itself the own chemistry needed for life, it's kind of an independent structure that is able to build its own material or matter making this system alive. And this should have happened elsewhere. Now, what we’re going to see, maybe we’re going to find out that all this life when it becomes very clever or civilised, calling life like that, it self-destroys, and it's clearly something that is a very practical outcome when you see all much thermonuclear weaponry we have on Earth right now. And we have the power of god of self-destruction. Maybe we’re going to see a planet that will have clear evidence that life has been extinct because we will see the remaining massive outcome of a big war that completely destroyed life on this planet. So it's all about ourselves, in a way, what we're talking about. It's all about the origins of life, the nature of life, and maybe it will tell us something about our capability of survival. And maybe we're going to learn something.

SS: You famously predicted that we'll find alien life within 30 years. When asked what makes you so sure you said that since life is basic chemistry, we just have to find the perfect combo of elements and conditions that are going to make life possible. So how do you know that a combination like that even exists somewhere?

DQ: Well, chemistry is the same everywhere. You can point a radio telescope and you realise that there are plenty of molecules, there is plenty of water. All the chemistry element you have on earth they are the same on Mars, they are the same on other stars, it’s exactly the same kind of functioning. So there is no, I mean, profound difference between any of this chemistry. What makes a difference is the fine-tuning of this. Now, I agree that maybe the fine-tuning on Earth was very special, that makes us very special. But there are so many stars, there are so many planets. So I can't believe that the fine-tuning has to be so precise that you have only one case. I just can't believe that because life doesn't seem to be that special. It looks special because we don't understand how to make it. But the day when we will have understood it, I think we will say, ‘Oh, yeah, that was just this. As soon as we have this ingredient, as soon as we have this element together, it happens.’ So it's just a matter of understanding what we're talking about. Now it looks magical because we don't understand. It’s a bit like any physical phenomenon, you could have people trying to understand 1000 years ago, that could have been magic because you don't understand why a bird is flying, it's magic. Now we can compute that; it’s very well known equations, and we building planes, we building rockets, we are going to the moon. So all this is okay. But it may not be easy, but we know to do that. So it's exactly the same. So 30 years is kind of a timescale, which is very long in science, it's impossible to predict. So it's usual time that everybody is using to say, ‘Oh, 30 years, everything is possible.’ So I think it was a good number to drop to the press.

 SS: I remember talking to the biochemist looking into the origins of life on Earth, and he says we're likely to find bacteria on other planets, sure, but not complex life forms like us. What's your take on this?

DQ: Yeah, that's a very interesting opinion. I don't know. Is there any, I mean, fundamental fact that prevents life to evolve? I don't know. That's a good point. And nobody knows this. Well, the most difficult bit is to start life. As soon as you start it, I think it's difficult to stop it. The reason why life is there we are on Earth, I mean, we have to remind ourselves, anything living here is alive, it's the same way, it's the same mechanisms, the same machinery, there is no difference between the piece of grass and between us in terms of functioning. Now, it seems that as soon as you find a trick to make it work, nothing can stop it. So the fact you are multicellular or monocellular, I think it's a detail to me, I just don't believe this is a fundamental limit here. Now there is a way more fundamental aspect – the concept of consciousness. I mean, do we always have as an end product of life some entity that is in a way aware or conscious and is impacting on its environment like us? This I don’t know. Maybe you need a lot of luck to happen, you need something, you need to get rid of dinosaurs to have mammifer moving ahead, and you need maybe some comet impact there. But there is a lot of stuff falling on earth anywhere. And there is a lot of deliveries. And so it's not that unlikely that a similar story could have happened on other planets as well. So I don't really know that. But I can't believe there is any locking mechanism, the most difficult part is to get the beginning, starting, as soon as you started, it seems to be a machine that nothing can stop and you have it, the only way to stop it is to have the system itself decided to put an end on it. That's it. Otherwise, I don't think you're going to stop it. Well, maybe the sun will decide at some point but in four billion years, we have still some time.

SS: So how accurately can we now reconstruct the conditions on Earth billions of years ago, when life is, you know, thought to have appeared?

DQ: Yeah, that is very difficult. Because Earth has the capability to heal itself or to self-rebuild itself so the plate tectonics is essentially removing any traces of ancient life. We do have this stromatolite , we know that this has happened. We know that there are some ancient rocks and we know that exactly the composition of the Earth at that time. But we're missing the early beginnings. This is why we're very excited to go to another planet like Mars or Venus. Mars is fascinating because Mars, we absolutely sure, had water, at least for the first billion years. Then something stopped, the plate tectonics stopped and the planet became in a way dead, never to evolve anymore. So Mars is possibly a planet that had some kind of co-evolution like the Earth for the first billion years. So going to Mars is maybe a way to probe what was the Earth in the first billion years. And the other way to do that would be to detect other planets on other stars and to look for other stars having a similar age that the earthly sun. And this is also something which is pretty cool in astrophysics because we don't only have many options, we can also look at different ages, we can pick a star, which is slightly younger or older, and we can compare the time evolution of a planet which, I think, is also a very important aspect that we need to study. So we should be able to get some hint of the evolution of the planet by looking at plenty of other planets orbiting other stars later on, and to compare these planets with the ones we have in our solar system.

SS: So finding out what exactly the Earth was like when life appeared will help us look for other planets like that and perhaps we will find life out there. But doesn't that mean that even if we do, we'll still have to wait like three billion years for some kind of amino acid to evolve into a thinking species?

DQ: Well, you know, this is the fascinating bit of the story on Earth -we have evidence that life was there after one billion years, which if you forgot the first half a billion when the earth was extremely hot and not really a pleasant environment. As soon as the environment becomes nice in a way in terms of organic chemistry, you have life. So it appears that life is a very fast process as soon as you have the right condition there. But what’s also interesting, life has been slow at the beginning to build up a capability to grow and to become multicellular. But as soon as you find a trick there, everything goes very fast, and the complexity of life, as soon as you have it, it's just zillions of possibilities that happen. So it's not very clear, what is the timescale, there is a possibility that life would start early on but would be very difficult to find because it is a very slow evolution, but that's okay. I think we can study plenty of planets, study the atmosphere, and we may not have any evidence of life there. But we may find an interesting atmosphere with the possibility of life evolution. That's not a problem finding the planet, it’s really finding what looks like the planet and what exactly is the structure and the atmosphere of this planet. And we may find out that the only interesting feature that we may suspect, be related to life, comes very late, and that will be a strong incentive that the life becomes visible at a stage of the atmosphere of a planet very late. I don't really know. But what I do know is we will be able to do that because you're not breaking any law of physics to do that. It just depends on the size of the telescopes and observing the right stars at the right moment.

SS: So we have a working theory about the origins of life – the primordial soup of four main elements somewhere in hydrothermal vents got life started, right? And yet scientists, like yourself, still say that we don't really know and we need to find out how life started. What is wrong with the current theory?

DQ: Well, there's nothing wrong, I think, the theory doesn't exist. This theory is not really built on the foundation of chemistry. The theory is built on comparison. So there has been some idea that at the bottom of the oceans, you have this energy that comes from the crust of the earth, and then you use the complexity of this vent, it's not actually the black smokers, it's really that the very cool vent and much more nice in a way, dark cities and that kind of places. And there is some similarity in the structure of this vent with some other mechanism of life, the one that like the Krebs cycle producing energy, for example. So it's by similarity and it comes essentially from the biologist that just points the possible origins there. Now, what has happened in the last couple of years is that biochemists have challenged this theory quite significantly by telling the biologist that that's fine, but it's not the theory because there is no backing in terms of chemistry. And people have started coming up with a new approach here, trying to reproduce the origin of life in the lab. And what they found out is instead of being on the bottom of the oceans, you can have a more massive life production at the surface of the planet. Essentially, you bring the ingredient you have which is the water, SO3 from the volcanic activity, the H-CN that comes from the delivery of the comet, very neutral atmosphere, the one you get when you build the planet full of CO2, and then a lot of UV radiation from the star that brings the energy mechanism for the chemistry to happen. And they realise that this is a kind of recent series of papers about five to six years old, you produce exactly the 20 amino acid which has been built up for life and then you produce also the ingredient, the key ingredient, that is a foundation like insolations for the future cell, the mechanism to reproduce the crypting and then also the mechanism, which is building the stuff, I mean, the gears in a way, all the proteins, the elements of the proteins there. So this is a kind of a new approach, it's not completely contradicting because in a way life has to happen, it can have chemistry there. But it seems it's not at the bottom of the ocean but the surface of the earth, which in terms of astrophysics is interesting, because we will be able to measure something from the surface, it's way more difficult to get [something] from the bottom, but from the surface of the planet. So we started to engage on that. And to check this theory, one of the easy checks is [to see] whether there is enough energy to make the chemical reaction happen. And we confirmed that recently, and recently, we’ve confirmed all the key steps of the reaction making the pathway to life. So I think there’ll be a serious change within a couple of years, some chemical lab will make life in a lab – life as we know it will be made from zero level, from scratch. And that would be the final demonstration that this is the origins of life.

SS: Well, I hope everything that you say comes true. Thank you very much for this amazing insight. It's always really interesting to dream and wonder if one day we could be living on another planet. So I hope that we get as much information as possible in the nearest future about all that because you know, I still want to be alive when something tangible happens in that area. Anyways, thank you a lot. Good luck with all your future endeavours. And I hope we meet sooner than 10 years to discuss – let's have like a little update on what's going on, okay?

DQ: With great pleasure. Thank you very much.

SS: Thank you so much. Bye.

DQ: Have a good day. Bye.