 Now, I am sad to say that we are nearing the end of our show here at the Royal Society's Summer Exhibition, but we have just enough time for a very special guest who's going to tell us about a seven-year mission to the icy moons of Jupiter. That's coming up next. Michelle Docherty is a space physicist who specializes in the giant planets Saturn and Jupiter and their moons. He's currently leading on the JUICE mission, which hopes to confirm if there are liquid oceans under the frozen surfaces of Europa, Ganymede and Callisto, and if so, could they support life? Michelle, thank you so much for joining us today. Thank you for inviting me. Tell me a little bit about how long your search for alien life has been going on. Probably my own involvement, the last 15 or 20 years, because I was involved in the Cassini spacecraft mission that went to Saturn, and my team made a discovery of outgassing of water vapor from one of the small moons called Enceladus. We realized that there was a liquid water ocean underneath the surface of Enceladus, but I think for me, probably one of the most important realizations planetary scientists have come to in the last 15 to 20 years is the fact that if you're looking for liquid water in our solar system, you don't have to look close to the sun. You can look much further away from the sun in the outer planets, but it's not on the surface. It's underneath the surface. Yes, even though it's really far away and not getting much of the sun's heat, that's not necessarily required to create liquid water. That's right. And there's a ball. There is a ball. Just conveniently just there. I will make use of. So what we think is happening at the three moons that we're going to is that as they orbit around Jupiter, their orbit is not quite circular. And so at times, they're closer to Jupiter and its gravitational field than on others. And when they're closer, the moon gets squeezed a bit. And so as it's orbiting around, it gets squeezed at different rates as it's going around. And that's helping keep the interior molten. Because of this movement. Because of the movement of the moon under the effect of the gravitational field of Jupiter. It's called tidal forcing or tidal heating is a better way to describe it. So as it's orbiting around Jupiter, the interior changes shape as it's going around Jupiter. That's really interesting. Now, tell me a little bit, let's rewind back. What was your story about coming into the career and science in the first place? It was quite weird. You know, I said yes to some things. I wasn't sure if I could do. And if we go back to when I was a child in South Africa, my dad built his own telescope. I remember he ground the sort of mirror of the telescope. And my sister and I did what we thought was the most important thing. And that was mix the concrete for the actual base of the telescope. I mean, concrete is the most important thing. As a structural engineer, I completely grew. There you go. There you go. And you know, if we hadn't been able to do that, then the telescope wouldn't have been able to stand up by itself. The foundations are the most important thing. Absolutely. In fact, my first view of Jupiter and its moons was through the telescope in our front garden. Wow. And I also saw Saturn and its rings as well. How old were you at this point? I was about 12 or 13. So quite a formative sort of experience, I guess. Yes, but I was at an all-girls school in South Africa and they didn't teach science. Not at all. And so, in fact, I did maths and biology and accountancy, I think. Those were my main three subjects. So no physics. Right. But I was good at maths and I didn't know what I wanted to do. And I was fortunate my dad worked at the local university and so I could get in for free. That's good. And they took a chance on me. The physics department took a chance on me and they said, okay, why don't you do a BSC? I didn't know if I could do it. But turns out I really enjoyed physics. But I got a PhD in applied maths. I then went to Germany on a two-year fellowship and then I was offered a job at Imperial College. And after about six months at Imperial College, I was asked if I wanted to put a magnetic field model together for a spacecraft mission that was going to Jupiter. I didn't know anything about it, but it sounded quite cool. So I said, yes. It sounds like this is a good philosophy in life to do things that we're not really sure we can do. I think so. There are times you need to be brave and you sort of learn on the job. I now think I vaguely know what I'm doing, but I said yes to something I wasn't sure of, but it was really exciting. And so that's how I got into planetary science. It's absolutely incredible. Now tell me about this very exciting sounding project, JUICE. What does it stand for? What is it doing? Okay. So it's a rather long-winded acronym, but it stands for Jupiter IC Moon Explorer. I like it. But what was really interesting is when we came up with the name, the European Space Agency said to us, really, JUICE, is that the best you can do? We're going to change the name after launch. Right. And then we were launched a couple of months ago and I said to them, are you going to change the name? Oh, no, we quite like it. So JUICE is what it's going to do. It's memorable. Yeah. So the mission is going to take about seven and a half years, you mentioned. What is the objective of the mission? Okay. So there are two different objectives. One is to try and understand the Jupiter system. But the one that I think is the real driver is to get an understanding about whether there's the potential for life to form. And that's in these kind of subterranean liquid water environments. That's right. So there are three moons, three of the large Galilean moons, which we're almost certain have got liquid water oceans underneath the surface. And can you give us an idea of the scale of these compared to planet Earth of the moons? Okay. The biggest moon is Ganymede and it is about the same size as Mercury. So it's about a third of the size of the Earth. And if there is this liquid water ocean on Ganymede, which we're almost certain there is, if it's a global ocean, there'll be more water in that ocean than there is on the water oceans on the Earth. So that gives you an idea about how much water there will be out there. Yeah. Yes. But so if you're looking to see where the life can exist, there are four things that you need. Yeah. You need liquid water. You need a heat source of some kind. You need organic material. And then you need those first three ingredients to be stable enough over a long enough period of time that something can actually happen. And so that's what we want to do with juice is we want to confirm that there's liquid water there, confirm their heat sources, we're almost certain there are because the water wouldn't be liquid if there wasn't a heat source. See if there's organic material. And then those are three of the four ingredients that we're actually searching for. And are you going to find like Loch Ness under there or are we looking at the little... Not with juice, we won't. No. What we're thinking will be there is bacteria of some kind. So I'm trying to think back was maybe the 1980s, there was a submersible that was sent to the deepest parts of the oceans on the earth where it's really cold, really dark, and they found bacteria close to vents. These vents. Yes. Yeah. Those are the kind of things that we're thinking about. Amazing. Yeah. Really exciting. And for you, from Professor Brian Cox, so should we have a listen to that? Of course. OK. Michelle, I have a question and it's probably a very unscientific question. So feel free to say I'm not answering that. But what I'd love to ask you is when juice arrives in Jupiter orbit and it makes those low flybys of Europa, perhaps it finds plumes emanating from the oceans of Europa. If I forced you to guess, do you think that we'll find evidence for biological activity in Europa's ocean? So what do you think? It's only a little question. I would be very surprised if we didn't. We won't do it with the two juice flybys, but we might do it with the NASA Europa clipper spacecraft that's got 50 flybys of Europa. All you need to do is you need to find organic material in the plumes. And then the implication is that that organic material is coming out from the ocean itself. So these are going to collect kind of material from the plumes to then analyze? Yes. Yes. So, you know, I think of the three moons, Europa, Ganymede and Callisto. Europa is the one where we think its liquid water is in contact with the silicate mantle. And so silicates will be leaking away from that mantle. But if we can fly through a plume as it's going off, or if we can't have clipper, NASA clipper mission can fly through the plume, then we can almost taste what's in the plume. I mean, that sounds very exciting, but there's a little bit of time to wait, I guess. Oh, I know. I know. Don't remind me. We can do that. We'll be back here in seven and a half years. Absolutely. If I'm still standing, I'll be back here. You will be. And we're going to talk about Loch Ness again. Okay. Maybe not. So...