Astrobiology Adventures: Exploring Life Beyond Earth

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Jonti Horner: Hi there.

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Andrew Dunkley: Thanks for joining us again. This is Space

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Nuts, where we talk astronomy and space

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science. And my name is Andrew Dunkley, your

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host. Great to have your company. Now,

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normally I'd be joined by Professor

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Fred Watson Watson, but he is away, uh,

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visiting family at the moment. And because he

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was going to be away and then I'm going to be

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away and we tried to cram episodes in and,

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uh, we just couldn't do enough in the amount

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of time we had. Uh, we invited Professor

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Jonty Horner to join us and we're, uh, going

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to do some specials. You might have heard the

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last one, uh, which was very engaging

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and interesting and fascinating and long. Uh,

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this time we, we're going down a different

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road. We're going to focus the whole

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programme on

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astrobiology. Strap in.

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We'll do that right now. 15 seconds.

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Guidance is internal. 10,

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9. Ignition sequence.

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Jonti Horner: Star. Space nuts. 5, 4, 3, 2.

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Andrew Dunkley: 1. 2, 3, 4, 5, 5, 4, 3,

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2, 1.

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Jonti Horner: Space nuts.

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Andrew Dunkley: Astronauts report it feels good. And here he

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is again, professor of astrophysics at the

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University of Southern Queensland, Johnty

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Horner. G', day, Johnty G'.

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Jonti Horner: Day. How are you going?

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Andrew Dunkley: I'm well. Good to see you again.

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And, uh, we've got a lot to talk about, so I

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think we're going to just dive on in.

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Now, in preparation for this astrobiology

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chat, you sent me a paper that you wrote,

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uh, and published on the Arxiv website.

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Uh, it's, um, ancient.

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Yeah, it's, it's coming up on 16

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years since you wrote that. But one of the

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interesting parts was, um, look, it's

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been a couple of decades now that we've been

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finding exoplanets. And as technology

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improves, it's only a matter of time before

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we start finding Earth like planets. And

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that's really going to make the search for

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life beyond our solar system really,

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really interesting. So those 16 years have

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passed. Have we got the. Have we got the

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equipment yet? I suspect we have.

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Jonti Horner: It depends where you're looking, I think. I

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mean in terms of looking at the planet. Round

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of the stars. We can now learn a lot more

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about them than we could 16 years ago when I

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wrote the paper, that particular paper. But

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we're still not there yet. And it's a

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perpetual thing. No matter how hard you work,

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there's always more to do. The other thing

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that goes along with it, which I think is

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worth saying right up at the very start, is,

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uh, searching fly false worries going to be

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one of the hardest things we've ever done.

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And, um, absence of evidence is not

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necessarily evidence of absence.

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What I mean by that is we could, in a

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remarkable turn of events in the next few

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months, find life elsewhere. You know, that's

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kind of the ultimate extreme, soonest

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possible. Um, very unlikely to happen.

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Alternatively, we might still be looking in a

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century. If we're still looking in a century.

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That doesn't mean that there isn't any life

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out out there, but what it will suggest

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to us is that life is relatively scarce.

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So to me, the sooner we find life elsewhere,

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that 8 will be awesome. Because, hey, look,

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we found life elsewhere, and we've answered

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the ultimate question, are we alone? But the

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sooner we find life elsewhere, the other

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thing it's telling us is that life must be

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fairly common in the universe. The scarcer

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life is, the harder it will be to find, and

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therefore the longer it will take us to find.

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And now the ultimate extreme of that is that,

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uh, this is the only place that there is

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life. And it'll be very hard

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to conclude that even if we were talking

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through a time warp, in 10,000 years, when

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humanity is taking its fledgling steps into

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the galaxy or whatever, if we haven't found

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life by then, we'll be confident that life is

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very rare and very precious. That doesn't

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mean that there is not life somewhere else in

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the universe. And it's one of the challenges

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with this. I would like to think that we'll

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find the answer to that question in our

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lifetime. But the only way we'll get an

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answer to the question, are we alone, um,

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within our lifetime? As if the answer is no,

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if that answer is that there is life

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elsewhere. And this is one of the big,

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really, really big open questions for

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humanity, open questions for science. You

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know, when I was a kid, when you were a kid,

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one of the big questions was, is the solar

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system unique? Or are there planets around

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other stars? And we'll talk about that more

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in the next episode. But there is nobody

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under the age of 30, 31 alive on

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this planet that grew up in that shared

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universe with you and I. So that fundamental

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question got answered and answered in ab.

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And answering that question is the first real

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step to say, is there life elsewhere

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beyond the solar system? Because in order to

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find life beyond the solar system, we first

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need to know that there's somewhere that life

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could exist. The question of life in the

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solar system is a different one. And that's

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all part of astrobiology. So if you bundle

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all of this together, that question of how we

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alone, um, is there life elsewhere? Which

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brings with it Questions like, what is the

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origin of life, why are we here? How did life

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begin, how did it get established, what are

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the processes needed? Everything like that,

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yeah, is what gets bundled in, in

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astrobiology. And astrobiology is a very,

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very weird science. I know certainly early in

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my career, a lot of older scientists viewed

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astrobiology in a similar way to the way a

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lot of astronomers view astrology almost. You

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know, they viewed it as being speculation,

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fiction and hook, you know, total bogus waste

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of time stuff. But it really isn't.

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Yeah, but one of the real challenges is, uh,

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it's not a question that one single

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discipline on its own can answer. Right. It's

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not like in astronomy, you, you're studying

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how, so you talk to astronomers in

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astrobiology, if we're looking at everything

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to do with life, astronomers like myself

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can't do it on their own, biologists can't do

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it on their own. You need geophysicists, you

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need chemists, you need every area of human

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scientific endeavour to come together.

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Because as scientists, our knowledge is

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somewhat siloed. I think I've said in

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previous episodes, the further you go away

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from what your speciality is, the more out of

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debt and the more superficial your knowledge

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is. So I always view my knowledge as being

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almost like a Christmas tree shape. I've got

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a lot of knowledge about a very narrow area

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at the top. And the further you go from that

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area, the less knowledge I have, but the

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broader my knowledge base gets. And I think

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every human's like that. And um, you can

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almost imagine that if you're trying to

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answer the question of what you need for

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life, where we should look, which, what we'll

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talk about a lot today. You need a level

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that's above a certain point on that

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Christmas tree of knowledge to be able to

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contribute to that from a scientific

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advancement point of view. And the area

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that you can cover yourself is generally

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fairly small. There's a lot of knowledge that

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is needed that is outside your silo.

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And so that's where the interdisciplinary

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nature comes in. No one discipline can answer

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it their own. And that means astrobiology

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conferences tend to be mind bogglingly

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bonkers. And you get people from very

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different disciplines along

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and you learn a lot that updates your

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knowledge from when you went to high school.

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You also learn a lot that isn't about the

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science, but is about the scientists.

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And it's really interesting because we all

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think we're individuals. It's like that Monty

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Python thing, isn't it? We're all individuals

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and there's a Voice at the back that goes,

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I'm not, I'm not. Yeah, it's a bit like that.

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Uh, we all think, we're all individuals and

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we're very unique in the way we think and the

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way we present. But when you go to one of

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these conferences, that's so

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multidisciplinary. The different

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disciplines present in different ways to one

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another. But within the discipline there are

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similarities, you know. So if you see the

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talks I give, I have beautiful pictures and

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bright text, white or yellow on them, limited

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text, usually a dark background. And that's

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really common for astronomers. You go to a

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talk by a kind of plate tectonics person

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and suddenly you've got this mishmash of

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colours on a total different background where

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there's a bit more text. But the colour

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schemes are a bit, to me, kind of psychedelic

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and like something you'd see out of a 1970s

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cartoon, you know, because they're used to

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working with these geological maps that, uh,

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um, have a very different colour palette and

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sensibility, I think. And then you get talks

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from the biologists where they've got the

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name of one bacterium and it fills half of

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the page because it's such a lengthy

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scientific name. And they've got loads of

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texts. And so you learn a lot about how

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what you study at university and what

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discipline you go into trains you to

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think and transit to problem solve. Because

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it trains you in a lot of different ways,

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essentially, programmes, people. And, um, you

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know, I find that side of things really

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fascinating because it's a good way to learn

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to improve your communication skills. And you

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also pick up all this abundance of,

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wow, I never knew that, you know. And that's

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what we need if we are to answer questions

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like, how did life begin? Where did life come

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from? Are we alone? Um, yeah.

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Andrew Dunkley: And that's really an interesting question

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because, uh, it could be life

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not as we know it.

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Like we, you know, we're assuming carbon

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based life forms, but there could be life

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forms that have been created out of a

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completely different soup mix. Two, uh,

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things I want to get out of the way quickly.

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The Drake Equation, which was, uh, created

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to try and assess how much intelligent

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life that was able to communicate existed in

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the universe. And the answer is still one.

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And the Fermi paradox, which says, you know,

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um, that statistically there's a

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high probability of extraterrestrial life.

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So where is everybody? And

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that's what astrobiology is really, isn't it?

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Where is everybody? And. And will they be

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people or will they be microbes?

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And I suppose my first question to you

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is, uh, you're talking about finding life

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outside the solar system. Aren't we likely

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to find it first within the solar system?

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Jonti Horner: So that's a really good question. I was going

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to talk about that a bit as well, because I

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think there are two different places.

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In a broad sense, we're looking for life

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elsewhere. One is in the

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outer solar system or on Mars, you know, in

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our solar system, on one of the planets or,

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uh, on the icy objects. And the other is

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beyond the solar system. And those two

257
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things have very different

258
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characteristics. What I mean

259
00:09:54.040 --> 00:09:56.760
by that is that, uh, objects that are in our

260
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solar system are in our backyard. They're the

261
00:09:59.160 --> 00:10:01.080
only things in astronomy that we can get up

262
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close and personal with. So in the solar

263
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system, the search for life elsewhere is

264
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being driven by robotic exploration. In the

265
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Moon. Yes, there's a little bit of

266
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observation from Earth. We saw that with the

267
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phosphine storey on Venus that I ranted about

268
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a little bit last week. Um, and, um, the

269
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wonderful caution shown by scientists that

270
00:10:20.400 --> 00:10:21.840
was not necessarily reflected in the

271
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coverage. Um, but a lot of the research

272
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in the solar system is robotic in nature. We

273
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send spacecraft to places to study them up

274
00:10:30.660 --> 00:10:33.020
close and personal. And we can't do that

275
00:10:33.020 --> 00:10:35.020
around other stars. Around other stars. It's

276
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very much a remote sensing type deal. So

277
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there are different ways of doing it. Now, I

278
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think there is a realistic chance we'll find

279
00:10:41.900 --> 00:10:44.260
life elsewhere in the solar system. There's a

280
00:10:44.260 --> 00:10:46.980
lot of good reasons for that. Now, before I

281
00:10:46.980 --> 00:10:48.740
dive into that a little bit, I'll just take a

282
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step back and come back to that point you

283
00:10:50.100 --> 00:10:51.980
made about life like us and carbon based life

284
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versus other things. Because it's really

285
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important to make explicit what is normally

286
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an implicit bias when

287
00:10:58.920 --> 00:11:01.080
scientists are talking about astrobiology.

288
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It's really made clear when you think about

289
00:11:03.640 --> 00:11:06.080
NASA and Issa's efforts on the moon, where

290
00:11:06.080 --> 00:11:08.200
they have. On, um, Mars, sorry, where they

291
00:11:08.200 --> 00:11:10.240
have aggressively said the strategy to look

292
00:11:10.240 --> 00:11:12.040
for life is to follow the water.

293
00:11:13.240 --> 00:11:15.880
What they're doing there is making

294
00:11:16.040 --> 00:11:18.400
an implicit assumption. That is an assumption

295
00:11:18.400 --> 00:11:20.480
that is not always written out and is clear,

296
00:11:20.480 --> 00:11:23.150
but is at the back of it, that life

297
00:11:23.230 --> 00:11:25.790
that we look for will be life like us. And I

298
00:11:25.790 --> 00:11:28.390
mean life like Earth life. Now we can

299
00:11:28.390 --> 00:11:30.310
imagine. You see it on science fiction all

300
00:11:30.310 --> 00:11:32.190
the time. You know, life that is very other.

301
00:11:32.190 --> 00:11:34.550
It might be molten metal monsters on a magma

302
00:11:34.550 --> 00:11:36.230
planet, or it might be an intelligent

303
00:11:36.230 --> 00:11:37.870
hydrogen cloud that nevertheless wants to

304
00:11:37.870 --> 00:11:40.110
flirt with Captain Kirk. It's

305
00:11:40.670 --> 00:11:42.510
very different kinds of life, but

306
00:11:42.990 --> 00:11:45.150
Fundamentally we only know of one type of

307
00:11:45.150 --> 00:11:47.990
life that does exist, and that's life

308
00:11:47.990 --> 00:11:50.740
like Earth life. And so when we

309
00:11:50.820 --> 00:11:53.660
look for life elsewhere, at ah, least in

310
00:11:53.660 --> 00:11:56.460
what is the early stages still, it is really

311
00:11:56.460 --> 00:11:58.220
important to look for something that we know

312
00:11:58.220 --> 00:12:01.060
can exist and does exist, rather than

313
00:12:01.060 --> 00:12:02.860
looking for things that we could speculate

314
00:12:02.860 --> 00:12:05.059
might exist. If you've got to focus your

315
00:12:05.059 --> 00:12:08.020
efforts with limited resources, it

316
00:12:08.020 --> 00:12:10.140
makes sense to follow the kind of well

317
00:12:10.140 --> 00:12:12.340
trodden footsteps of what we know about life

318
00:12:12.340 --> 00:12:14.580
on Earth. And um, from an astronomer's point

319
00:12:14.580 --> 00:12:16.860
of view, life on Earth needs three things.

320
00:12:16.860 --> 00:12:19.190
You know, it needs liquid water, it needs a

321
00:12:19.190 --> 00:12:20.830
source of energy and a source of nutrients.

322
00:12:20.830 --> 00:12:22.550
And quite often those two are the same thing,

323
00:12:22.550 --> 00:12:25.390
but not always. And wherever we find those

324
00:12:25.390 --> 00:12:27.470
things on Earth, we find life in abundance.

325
00:12:27.470 --> 00:12:29.310
And once life gets there, it's really hard to

326
00:12:29.310 --> 00:12:31.510
get rid of. You know, anybody who's had ants

327
00:12:31.510 --> 00:12:33.710
getting into their kitchen or the mice plague

328
00:12:33.710 --> 00:12:36.590
that we talked about last week knows just how

329
00:12:37.310 --> 00:12:40.110
life, once it gets established, keeps going.

330
00:12:40.590 --> 00:12:43.150
And so it makes sense. And a lot of what I'll

331
00:12:43.150 --> 00:12:45.190
talk about for all the rest of the episode is

332
00:12:45.190 --> 00:12:47.430
kind of based on this assumption that we're

333
00:12:47.430 --> 00:12:50.180
looking, at least initially for life like

334
00:12:50.180 --> 00:12:52.900
us, has the same needs as us. Where the US is

335
00:12:52.900 --> 00:12:55.220
abroad, the entire panel play of life on

336
00:12:55.220 --> 00:12:58.220
Earth rather than us as in me and the having

337
00:12:58.220 --> 00:13:00.540
this chat back and forward. What

338
00:13:00.860 --> 00:13:02.900
that leads to though is a lot of studies that

339
00:13:02.900 --> 00:13:04.500
have been done for the solar system are very

340
00:13:04.500 --> 00:13:07.500
water driven. And if you go back decades, you

341
00:13:07.500 --> 00:13:10.220
could go back to the late 1800s when people

342
00:13:10.220 --> 00:13:12.060
were obsessed with this idea that there was

343
00:13:12.060 --> 00:13:14.220
an advanced technological civilization on

344
00:13:14.220 --> 00:13:16.720
Mars that was running out of time because the

345
00:13:16.720 --> 00:13:19.000
planet was desolate and barren. And this was

346
00:13:19.000 --> 00:13:21.160
all motivated by the observations of the

347
00:13:21.160 --> 00:13:23.960
canali, the channels on Mars that don't

348
00:13:23.960 --> 00:13:26.680
exist, which were mistranslated as canals and

349
00:13:26.680 --> 00:13:28.720
canals on Earth are a very clear sign of

350
00:13:28.880 --> 00:13:31.720
human activity. Yeah, People at

351
00:13:31.720 --> 00:13:33.800
that time were so certain that we'd already

352
00:13:33.800 --> 00:13:35.520
found life that when there was a prize

353
00:13:35.520 --> 00:13:38.240
awarded, um, a prize laid

354
00:13:38.240 --> 00:13:39.960
out, sorry, in announced, I think it was like

355
00:13:39.960 --> 00:13:42.520
in 1899 or something, for the search for

356
00:13:42.520 --> 00:13:44.440
life, for the first person to discover life

357
00:13:44.440 --> 00:13:46.000
elsewhere, to find evidence of life

358
00:13:46.000 --> 00:13:48.420
elsewhere. That prize explicitly

359
00:13:48.420 --> 00:13:51.100
excluded Mars because it was felt that life

360
00:13:51.100 --> 00:13:53.140
on Mars was so well established that that was

361
00:13:53.140 --> 00:13:55.260
a no brainer. You know, it was such a thing

362
00:13:55.260 --> 00:13:56.780
in popular culture that when the War of the

363
00:13:56.780 --> 00:13:58.900
Worlds broadcast happened in the 1930s,

364
00:13:59.300 --> 00:14:01.380
people thought it was live news coverage and

365
00:14:01.380 --> 00:14:01.940
panicked.

366
00:14:01.940 --> 00:14:04.220
Andrew Dunkley: Yes. You know, the night that panicked

367
00:14:04.220 --> 00:14:04.740
America.

368
00:14:04.900 --> 00:14:07.620
Jonti Horner: Yeah. And there's this whole heritage of

369
00:14:08.420 --> 00:14:10.740
our expectation of life being common

370
00:14:11.220 --> 00:14:13.620
and it being lifelike, us requiring water.

371
00:14:14.770 --> 00:14:17.130
When we went to Mars, like in the 1960s with

372
00:14:17.130 --> 00:14:19.850
spacecraft, Mars was shown to be the

373
00:14:19.850 --> 00:14:21.450
desolate, arid world we knew today. And that

374
00:14:21.450 --> 00:14:23.490
put to an end the thoughts of an advanced

375
00:14:23.490 --> 00:14:26.210
civilization there. And, um, from that time

376
00:14:26.210 --> 00:14:28.930
onwards there was a period where arguments in

377
00:14:28.930 --> 00:14:30.730
astrobiology fell very much out of favour,

378
00:14:30.730 --> 00:14:32.010
out of fashion. And it was kind of viewed

379
00:14:32.010 --> 00:14:34.010
much more likely that life was almost unique,

380
00:14:34.010 --> 00:14:36.490
we were alone, um, there was no way you could

381
00:14:36.490 --> 00:14:36.650
look.

382
00:14:36.650 --> 00:14:39.090
And there's this argument that I often hear

383
00:14:39.820 --> 00:14:42.540
espouse that water is scarce in the universe.

384
00:14:43.180 --> 00:14:45.060
And that makes my head hurt. I think this is

385
00:14:45.060 --> 00:14:47.660
one of those big myths that is a myth of

386
00:14:47.660 --> 00:14:50.300
miscommunication or a myth of

387
00:14:51.420 --> 00:14:53.980
language being a personal

388
00:14:54.060 --> 00:14:56.900
thing. What I mean by that is, and I'm

389
00:14:56.900 --> 00:14:58.580
always trying to be very aware of this when

390
00:14:58.580 --> 00:15:01.100
I'm, uh, as a communicator, the

391
00:15:01.260 --> 00:15:03.620
words have different meanings to different

392
00:15:03.620 --> 00:15:06.460
people. And so the same word that I

393
00:15:06.460 --> 00:15:08.660
say you'll hear and it doesn't always mean

394
00:15:08.660 --> 00:15:10.380
the same thing to you or me. And one of the

395
00:15:10.380 --> 00:15:12.100
best things, best examples of this is when

396
00:15:12.100 --> 00:15:14.900
you get people who are trying to argue

397
00:15:14.900 --> 00:15:17.140
against an area of science, maybe vaccines,

398
00:15:17.140 --> 00:15:19.100
maybe climate change, maybe something less

399
00:15:19.100 --> 00:15:21.420
controversial. You'll often hear people say

400
00:15:21.420 --> 00:15:23.620
that, well, climate change is just a theory,

401
00:15:23.620 --> 00:15:25.820
or, uh, vaccines are just a theory, or the

402
00:15:25.820 --> 00:15:28.420
Big Bang is just a theory. And to a lot of

403
00:15:28.420 --> 00:15:31.420
people a theory just means a loose

404
00:15:31.420 --> 00:15:34.140
idea. A lot of people will say,

405
00:15:34.780 --> 00:15:36.380
why isn't your car starting this morning?

406
00:15:36.380 --> 00:15:39.160
Well, I've got a theory. To a scientist, a

407
00:15:39.160 --> 00:15:41.160
theory is a very different beast and it's

408
00:15:41.160 --> 00:15:43.080
tied to the ability to make testable

409
00:15:43.080 --> 00:15:45.880
predictions and, um, repeated testing.

410
00:15:46.120 --> 00:15:48.400
There's a lot of philosophy of science. I did

411
00:15:48.400 --> 00:15:50.470
a philosophy of physics course at, uh,

412
00:15:50.470 --> 00:15:52.160
university when I was 18 and I wish I'd done

413
00:15:52.160 --> 00:15:53.600
it when I was at the end of my degree. Not

414
00:15:53.600 --> 00:15:54.880
the start, because I'd have got a lot more

415
00:15:54.880 --> 00:15:56.880
out of it. But there are people who've

416
00:15:56.880 --> 00:15:59.520
aggressively studied the philosophy of the

417
00:15:59.520 --> 00:16:02.240
scientific method and even that philosophy

418
00:16:02.240 --> 00:16:03.520
varies a little bit, discipline to

419
00:16:03.520 --> 00:16:05.760
discipline. A lot of other disciplines that

420
00:16:05.760 --> 00:16:07.750
are the experimental ones are a very much

421
00:16:07.750 --> 00:16:10.710
more hypothesis driven than astronomy,

422
00:16:10.710 --> 00:16:12.190
where we say, I'm interested in what this is,

423
00:16:12.190 --> 00:16:13.590
let's have a look. There's not really a

424
00:16:13.590 --> 00:16:15.110
hypothesis. I just want to look at it and

425
00:16:15.110 --> 00:16:17.990
find out. At least that's how I work. But you

426
00:16:17.990 --> 00:16:20.430
also have this thing where, at least from my

427
00:16:20.430 --> 00:16:22.390
philosophy, you can never prove a Theory, but

428
00:16:22.390 --> 00:16:24.870
you can disprove a theory. What I mean by

429
00:16:24.870 --> 00:16:27.630
that is if you test a theory a million times

430
00:16:28.110 --> 00:16:30.750
and each time it's backs it up, you haven't

431
00:16:30.750 --> 00:16:32.870
proven that theory. You've just shown that

432
00:16:32.870 --> 00:16:34.790
theory is a very good approximation to what's

433
00:16:34.790 --> 00:16:36.790
actually happening. So take the example of me

434
00:16:36.790 --> 00:16:39.130
flipping a coin, I can have a theory theory

435
00:16:39.130 --> 00:16:41.730
that says coins will always land heads or

436
00:16:41.730 --> 00:16:44.530
tails. Test that a million times and odds are

437
00:16:44.530 --> 00:16:46.410
a million times you'll land heads or tails.

438
00:16:46.410 --> 00:16:48.210
But you've not proven that theory. You've

439
00:16:48.210 --> 00:16:50.010
just said it's a very close approximation to

440
00:16:50.010 --> 00:16:52.170
the truth. You could toss them 10 million

441
00:16:52.170 --> 00:16:53.650
times and one time your coin lands on its

442
00:16:53.650 --> 00:16:55.570
edge and balances. Yeah, that one

443
00:16:55.570 --> 00:16:57.010
observation. So as long as it's well

444
00:16:57.010 --> 00:16:58.690
documented and is repeatable is enough to

445
00:16:58.690 --> 00:17:00.610
kill that theory. And then you need to

446
00:17:00.610 --> 00:17:03.130
develop something more complex. You know,

447
00:17:03.610 --> 00:17:04.810
that's where it goes from.

448
00:17:04.810 --> 00:17:07.210
Now, that's a very roundabout way of coming

449
00:17:07.210 --> 00:17:10.080
back at this water being scarce myth.

450
00:17:10.880 --> 00:17:13.640
I think where that comes from is when you

451
00:17:13.640 --> 00:17:16.150
talk to me about water, I am,

452
00:17:16.150 --> 00:17:18.880
um, just thinking about the molecule.

453
00:17:18.960 --> 00:17:21.880
I'm not thinking about the physical state. So

454
00:17:21.880 --> 00:17:23.960
to me, water can be water ice, it can be

455
00:17:23.960 --> 00:17:26.520
liquid water, it can be water vapour. But to

456
00:17:26.520 --> 00:17:28.800
most people, if you say water, they visualise

457
00:17:28.800 --> 00:17:31.400
liquid water. Yeah, if, if I say, would you

458
00:17:31.400 --> 00:17:33.040
like some water? You're not expecting me to

459
00:17:33.040 --> 00:17:35.160
immediately start steaming your face. You're

460
00:17:35.160 --> 00:17:36.720
expecting a glass of water. Right.

461
00:17:38.530 --> 00:17:40.330
What that means is that when people look out

462
00:17:40.330 --> 00:17:42.090
of the solar system and look everywhere else,

463
00:17:42.090 --> 00:17:44.050
we see this thing that Earth is the only

464
00:17:44.050 --> 00:17:46.850
place where we have abundant liquid water all

465
00:17:46.850 --> 00:17:49.770
the time on the surface. And so people

466
00:17:49.770 --> 00:17:51.530
have this idea that water is scarce, where

467
00:17:51.530 --> 00:17:54.130
what they're really thinking is liquid water

468
00:17:54.450 --> 00:17:57.170
on the surface of an object is scarce.

469
00:17:58.050 --> 00:18:00.650
But that drove a lot of this idea that life

470
00:18:00.650 --> 00:18:02.370
will be scarce because life needs liquid

471
00:18:02.370 --> 00:18:04.580
water. On Earth, the earthy and lipidates

472
00:18:04.580 --> 00:18:06.700
with liquid water, ergo, uh, life will be

473
00:18:07.020 --> 00:18:09.660
scarce. That's moved on though, in about the

474
00:18:09.660 --> 00:18:11.460
last three or four decades, partially with

475
00:18:11.460 --> 00:18:13.580
the exploration of Mars, where we're getting

476
00:18:14.060 --> 00:18:16.380
an overwhelmingly greater amount m of

477
00:18:16.380 --> 00:18:18.100
evidence that Mars in the past was warm and

478
00:18:18.100 --> 00:18:20.260
wet, that it had oceans and lakes. They may

479
00:18:20.260 --> 00:18:21.580
have been slushy or they may have been

480
00:18:21.740 --> 00:18:24.140
properly liquid, but it had oceans and lakes

481
00:18:24.140 --> 00:18:26.380
for a long time of liquid water. And we've

482
00:18:26.380 --> 00:18:27.860
even got evidence that there is permanent

483
00:18:27.860 --> 00:18:29.820
liquid water on Mars as we're talking now in

484
00:18:29.820 --> 00:18:31.290
the form of liquid water in the Martian Mars

485
00:18:31.520 --> 00:18:33.800
polar ice caps. And you get temporary liquid

486
00:18:33.800 --> 00:18:36.040
Water running on the surface. The other thing

487
00:18:36.040 --> 00:18:38.240
we found in the solar system is liquid water

488
00:18:38.880 --> 00:18:41.520
in astonishing abundance in the outer solar

489
00:18:41.520 --> 00:18:44.520
system, protected by shells of ice on the

490
00:18:44.520 --> 00:18:47.160
icy satellites of the giant planets. On the

491
00:18:47.160 --> 00:18:48.920
dwarf planet Pluto, or inside the dwarf

492
00:18:48.920 --> 00:18:51.650
planet Pluto, probably in the larger, uh,

493
00:18:51.650 --> 00:18:53.280
Edgeworth Kuiper Belt objects, Trans

494
00:18:53.280 --> 00:18:55.880
Neptunian objects, maybe in other places as

495
00:18:55.880 --> 00:18:58.080
well, even in places as small as Enceladus.

496
00:18:58.870 --> 00:19:01.030
So there's been this revolution from the

497
00:19:01.030 --> 00:19:02.670
point of view of the solar system through my

498
00:19:02.670 --> 00:19:05.310
lifetime that actually liquid water isn't

499
00:19:05.310 --> 00:19:08.030
scarce. Coupled to the fact that the Earth is

500
00:19:08.030 --> 00:19:10.230
actually remarkably dry as a planet, that

501
00:19:10.230 --> 00:19:11.910
suddenly opened up people's perspectives

502
00:19:11.910 --> 00:19:13.790
again that the solar system is a good place

503
00:19:13.790 --> 00:19:16.270
to look for life. And that's driving a lot of

504
00:19:16.270 --> 00:19:17.870
exploration, a lot of missions. All the Mars

505
00:19:17.870 --> 00:19:20.350
exploration past and, um, future focused

506
00:19:20.350 --> 00:19:22.590
around that idea. The fact that we've got two

507
00:19:22.590 --> 00:19:24.630
missions going to the Jovian IC satellites at

508
00:19:24.630 --> 00:19:26.710
the minute Juice and, um, the Jupiterizing

509
00:19:26.710 --> 00:19:29.110
Moons Explorer and the Europa Clipper, which

510
00:19:29.110 --> 00:19:31.350
are to characterise those moons better to

511
00:19:31.350 --> 00:19:33.230
prepare for potential future landings in the

512
00:19:33.230 --> 00:19:35.830
2000-40s or-50s to get through the ice and

513
00:19:35.830 --> 00:19:37.790
look at what's underneath. We've got the

514
00:19:37.790 --> 00:19:39.910
Dragonfly mission going out to Titan,

515
00:19:40.070 --> 00:19:41.750
launching in a couple of years time, probably

516
00:19:41.750 --> 00:19:44.310
next year, ah, hoping to get there 2034.

517
00:19:44.630 --> 00:19:46.670
That will land on the only other place that

518
00:19:46.670 --> 00:19:49.270
has liquid on its surface exposed to the

519
00:19:49.270 --> 00:19:50.910
atmosphere in the solar system, and that's

520
00:19:50.910 --> 00:19:52.750
Titan. With lakes of liquid methane and

521
00:19:52.750 --> 00:19:54.830
ethane. The water there is harder than

522
00:19:54.830 --> 00:19:57.060
granite and makes up the mountain. But

523
00:19:57.060 --> 00:19:58.780
there's this huge effort to explore our solar

524
00:19:58.780 --> 00:20:00.940
system and actually go there and look, which

525
00:20:00.940 --> 00:20:02.980
we can't do when we're looking at planets

526
00:20:02.980 --> 00:20:05.660
around other stars. And by going there and

527
00:20:05.660 --> 00:20:08.500
looking if there is anything there, past or

528
00:20:08.500 --> 00:20:11.100
present, eventually we'll find it. Now, that

529
00:20:11.340 --> 00:20:13.420
immediately then poses a really fascinating

530
00:20:13.420 --> 00:20:16.260
one. So if we find life on Mars or find life

531
00:20:16.260 --> 00:20:18.860
on Europa, if we can

532
00:20:19.020 --> 00:20:21.660
look at that life and figure out

533
00:20:22.270 --> 00:20:25.110
its heritage, figure out its DNA, and I'm not

534
00:20:25.110 --> 00:20:27.150
a biologist, so I'll be a little woolly on

535
00:20:27.150 --> 00:20:29.710
that. It will be very quick and very

536
00:20:29.710 --> 00:20:31.510
apparent whether that life has a shared

537
00:20:31.510 --> 00:20:33.590
origin to life on Earth or whether it has a

538
00:20:33.590 --> 00:20:35.990
separate origin to life on Earth. Now, the

539
00:20:35.990 --> 00:20:37.669
separate origin would mean that life got

540
00:20:37.669 --> 00:20:40.630
started simultaneously on two

541
00:20:40.630 --> 00:20:43.590
objects in the same planetary system in

542
00:20:43.590 --> 00:20:46.110
an icy backwater of a fairly unremarkable

543
00:20:46.110 --> 00:20:48.960
galaxy. If it got started two places side

544
00:20:48.960 --> 00:20:51.080
by side, surely that means life gets started

545
00:20:51.080 --> 00:20:53.960
more easily than we expect. Therefore, life

546
00:20:53.960 --> 00:20:56.320
should be common in the universe. That would

547
00:20:56.320 --> 00:20:59.080
be an obvious logical continuation. The other

548
00:20:59.080 --> 00:21:00.960
option is that we find life elsewhere in the

549
00:21:00.960 --> 00:21:02.720
solar system and it has a shared heritage to

550
00:21:02.720 --> 00:21:04.810
life on Earth. What that means is that, uh,

551
00:21:04.810 --> 00:21:06.880
we analyse its makeup, we find that it has

552
00:21:06.880 --> 00:21:09.680
DNA like Earth, DNA that has a shared

553
00:21:09.680 --> 00:21:12.040
universal common ancestor. And what that

554
00:21:12.040 --> 00:21:13.800
suggests is that once life gets started

555
00:21:13.880 --> 00:21:16.200
somewhere, it's transmissible. You know,

556
00:21:16.200 --> 00:21:17.600
you've got that old thing of don't go near

557
00:21:17.600 --> 00:21:19.440
Earth, it's got humans, they're contagious.

558
00:21:20.240 --> 00:21:22.720
This is the same kind of idea. If we find

559
00:21:22.720 --> 00:21:24.520
life on Mars and that life has a shared

560
00:21:24.520 --> 00:21:26.960
heritage with life on Earth, that

561
00:21:27.120 --> 00:21:29.680
validates strongly support c idea of

562
00:21:29.680 --> 00:21:32.200
panspermia, which I've had a student just

563
00:21:32.200 --> 00:21:35.000
submit his PhD thesis studying the

564
00:21:35.000 --> 00:21:36.680
idea that life can transfer between the

565
00:21:36.680 --> 00:21:39.280
planets. Now, again, if life can transfer

566
00:21:39.280 --> 00:21:40.760
easily enough to be found in multiple

567
00:21:40.760 --> 00:21:42.640
locations in the solar system from a simple

568
00:21:43.140 --> 00:21:45.690
single origin and, uh, maybe even Earth, uh,

569
00:21:45.700 --> 00:21:47.380
wasn't that origin. You know, maybe we're

570
00:21:47.380 --> 00:21:50.140
Martians, maybe we're Venusians or Venerians.

571
00:21:50.140 --> 00:21:52.260
I think that Venerian used to be the

572
00:21:52.260 --> 00:21:53.980
adjective for Venus. Adjective, the right

573
00:21:53.980 --> 00:21:55.540
word, used to be the word for Venus in the

574
00:21:55.540 --> 00:21:57.620
way that Martian was for Mars, but it was a

575
00:21:57.620 --> 00:21:59.860
bit too close to venereal, um, because.

576
00:22:01.140 --> 00:22:03.340
So they changed it. But anyway, um, but we

577
00:22:03.340 --> 00:22:05.940
could be venereal creatures. Um, we don't

578
00:22:05.940 --> 00:22:07.700
know. But what that suggests is that if life

579
00:22:07.700 --> 00:22:10.570
is transferred easily and effectively once it

580
00:22:10.570 --> 00:22:12.570
originates, life could be coming in the

581
00:22:12.570 --> 00:22:15.330
universe. So to me, finding life in the solar

582
00:22:15.330 --> 00:22:16.810
system would be awesome. I think it's

583
00:22:16.810 --> 00:22:19.210
eminently feasible. And either way, it will

584
00:22:19.210 --> 00:22:21.490
shed new light on the commonality of life

585
00:22:21.650 --> 00:22:24.410
beyond the solar system. We will be looking

586
00:22:24.410 --> 00:22:27.090
for life like us. It is possible to imagine

587
00:22:27.090 --> 00:22:28.770
life that is not like us, that has different

588
00:22:28.770 --> 00:22:30.410
requirements, but that will probably be a bit

589
00:22:30.410 --> 00:22:33.410
harder to find and we don't know

590
00:22:33.410 --> 00:22:36.060
what it would be. Whereas with life like us,

591
00:22:36.060 --> 00:22:38.340
we know things to look for. So that makes it

592
00:22:38.340 --> 00:22:40.220
a bit easier for us to look for life like us.

593
00:22:40.700 --> 00:22:43.020
It also makes it, I'd say,

594
00:22:43.500 --> 00:22:45.620
a little bit stronger as a case when you're

595
00:22:45.620 --> 00:22:47.780
asking for funding because you can say, well,

596
00:22:47.780 --> 00:22:49.820
we already know this kind of life can exist,

597
00:22:50.140 --> 00:22:51.620
so we're going to look at a place where the

598
00:22:51.620 --> 00:22:53.060
conditions are similar to where we know it

599
00:22:53.060 --> 00:22:54.980
does exist and, um, see if we find it there

600
00:22:54.980 --> 00:22:55.420
as well.

601
00:22:55.820 --> 00:22:58.660
Andrew Dunkley: Okay, let's take a short break. Uh, this

602
00:22:58.660 --> 00:23:01.020
is Space Nuts with Andrew Dunkley and

603
00:23:01.020 --> 00:23:02.700
Professor Jonty Horner.

604
00:23:05.210 --> 00:23:06.250
Yeah, I'm going to step off the

605
00:23:06.250 --> 00:23:06.810
Jonti Horner: lamb now

606
00:23:09.050 --> 00:23:11.370
that's one small step for man,

607
00:23:14.410 --> 00:23:16.730
one giant leap for man.

608
00:23:17.290 --> 00:23:18.330
Space nuts.

609
00:23:19.290 --> 00:23:21.130
Andrew Dunkley: It's not Professor Fred Watson Watson at the

610
00:23:21.130 --> 00:23:22.970
moment. He's away. We've got Professor John

611
00:23:22.970 --> 00:23:25.330
T. Horner, and we're talking astrobiology in

612
00:23:25.330 --> 00:23:27.450
this little, uh, special edition.

613
00:23:28.050 --> 00:23:30.650
Um, one thing I heard in the news recently,

614
00:23:30.650 --> 00:23:32.330
and I think Fred Watson and I talked about it

615
00:23:32.330 --> 00:23:34.210
was, uh, you know, we've been talking about

616
00:23:34.210 --> 00:23:36.090
water. And if you want to find the people,

617
00:23:36.470 --> 00:23:38.750
find the water, that sort of thing. But there

618
00:23:38.750 --> 00:23:41.210
was one particular study that was, uh,

619
00:23:41.430 --> 00:23:43.190
recently released that says if you want to

620
00:23:43.190 --> 00:23:45.990
find the people, find the coal. What do you

621
00:23:45.990 --> 00:23:46.790
think of that theory?

622
00:23:47.190 --> 00:23:49.430
Jonti Horner: That's an interesting one. So that's the idea

623
00:23:49.430 --> 00:23:51.310
that, uh, if you want to find somebody to

624
00:23:51.310 --> 00:23:53.950
talk to, there needs to be something to fuel

625
00:23:53.950 --> 00:23:56.230
an industrial revolution. And again, this is,

626
00:23:56.870 --> 00:23:58.950
I think, science fiction sometimes. Does this

627
00:23:58.950 --> 00:24:00.990
really ask these really interesting questions

628
00:24:00.990 --> 00:24:03.760
of almost is the path that we

629
00:24:03.760 --> 00:24:06.680
have followed the one that everyone

630
00:24:06.680 --> 00:24:08.280
will follow? You know, because there's so

631
00:24:08.280 --> 00:24:10.960
much to some degree randomness in

632
00:24:11.040 --> 00:24:13.840
the things that have driven our knowledge

633
00:24:13.840 --> 00:24:16.280
and our development of things. You know, um,

634
00:24:16.280 --> 00:24:18.600
obviously a good example is a famous myth

635
00:24:18.600 --> 00:24:21.080
about penicillin that if, um, you leave your

636
00:24:21.080 --> 00:24:22.920
bread out and it goes mouldy, that makes your

637
00:24:22.920 --> 00:24:25.720
poultice more effective. Um, and that was an

638
00:24:25.720 --> 00:24:28.600
incredible scientific revolution driven

639
00:24:28.600 --> 00:24:30.220
by that discovery. There was.

640
00:24:31.490 --> 00:24:33.490
Who's to say other civilizations would have

641
00:24:33.490 --> 00:24:36.050
the same discoveries in the same order. Now,

642
00:24:36.850 --> 00:24:39.650
to advance, we have required advances in

643
00:24:39.890 --> 00:24:42.210
energy in order to allow us to better

644
00:24:42.850 --> 00:24:44.930
develop technology and develop the things

645
00:24:44.930 --> 00:24:46.850
that everything's made of. You know, if we

646
00:24:46.850 --> 00:24:49.010
didn't have anything that you could burn,

647
00:24:49.570 --> 00:24:51.730
it would be very, very challenging to smelt

648
00:24:51.730 --> 00:24:53.810
metal. If you couldn't smelt metal, how do

649
00:24:53.810 --> 00:24:55.010
you build electronics?

650
00:24:55.250 --> 00:24:57.170
Andrew Dunkley: You are spot on. That's exactly what the

651
00:24:57.170 --> 00:25:00.010
article was all about. And, uh, the

652
00:25:00.010 --> 00:25:02.650
bottom line was, uh, that because of the

653
00:25:02.650 --> 00:25:05.650
timing required, it lessens

654
00:25:06.130 --> 00:25:09.130
the likelihood of us finding, uh, people

655
00:25:09.130 --> 00:25:11.730
like us. It reduces the odds.

656
00:25:11.890 --> 00:25:14.050
Jonti Horner: And this is where there's a difference

657
00:25:14.050 --> 00:25:16.010
between the search for extraterrestrial

658
00:25:16.010 --> 00:25:18.450
intelligence and the search for life. So the

659
00:25:18.450 --> 00:25:20.290
search for extraterrestrial intelligence is

660
00:25:20.290 --> 00:25:22.610
like a subset of the search for life? Yeah,

661
00:25:22.610 --> 00:25:25.210
search for life is a search for bacteria as

662
00:25:25.210 --> 00:25:27.610
much as the search for, uh, communicative

663
00:25:27.610 --> 00:25:30.470
aliens. And there's been a lot of stuff

664
00:25:30.470 --> 00:25:32.950
written and discussed about whether

665
00:25:33.190 --> 00:25:35.630
evolutionary quirks have benefited us by

666
00:25:35.630 --> 00:25:37.550
being here. You know, in terms of we're a

667
00:25:37.550 --> 00:25:39.430
social communal animal that shares resources

668
00:25:39.430 --> 00:25:42.190
and shares learning. There have been other

669
00:25:42.190 --> 00:25:43.910
ones like that from Ant Colins. And I'm

670
00:25:43.910 --> 00:25:46.430
listening to a very Chill and very

671
00:25:46.430 --> 00:25:48.950
silly, um, lit

672
00:25:48.950 --> 00:25:50.790
rpg, I think would be the description of the

673
00:25:50.790 --> 00:25:53.270
genre series of books called Chrysalis at the

674
00:25:53.270 --> 00:25:55.990
minute, where a young boy who dies for

675
00:25:56.070 --> 00:25:58.660
reasons is reincarnated in the bottom born

676
00:25:58.810 --> 00:26:01.570
body of an ant. And it's a book about him

677
00:26:01.570 --> 00:26:03.490
as an ant and his life in the colony and

678
00:26:03.490 --> 00:26:06.230
stuff, and it's bonkers. But, um,

679
00:26:06.570 --> 00:26:08.770
you've got an advanced social species there

680
00:26:08.770 --> 00:26:11.050
and he finds ways, without too many spoilers,

681
00:26:11.050 --> 00:26:12.610
of giving them intelligence and what happens

682
00:26:12.610 --> 00:26:14.970
afterwards. There's a few species in the

683
00:26:14.970 --> 00:26:16.650
history of Earth that have that kind of

684
00:26:16.650 --> 00:26:19.530
communal sharing of information thing. We're

685
00:26:19.530 --> 00:26:20.930
the only ones that have achieved what we've

686
00:26:20.930 --> 00:26:23.730
achieved. Some arguments are that's down to

687
00:26:23.730 --> 00:26:26.160
the development of language and our ability

688
00:26:26.160 --> 00:26:28.320
to produce complex language, and also the

689
00:26:28.320 --> 00:26:30.640
opposable thumb being quite important. So

690
00:26:30.640 --> 00:26:33.280
there's a lot of stuff that there are many

691
00:26:33.280 --> 00:26:35.520
steps between the development of life and the

692
00:26:35.520 --> 00:26:38.080
development of intelligence. And, uh, the

693
00:26:38.080 --> 00:26:39.840
development of intelligence itself doesn't

694
00:26:39.840 --> 00:26:41.160
necessarily mean the development of

695
00:26:41.160 --> 00:26:43.480
technological intelligence. You know, a lot

696
00:26:43.480 --> 00:26:45.680
of discussions about all the things octopi or

697
00:26:45.680 --> 00:26:48.520
octopods or octopiddles, octopi could

698
00:26:48.520 --> 00:26:50.760
achieve if they lived for more than three

699
00:26:50.760 --> 00:26:52.240
years. And if they were a social animal,

700
00:26:52.870 --> 00:26:54.550
they've got incredible brands. We're learning

701
00:26:54.550 --> 00:26:56.630
more and more about some of the brain power

702
00:26:56.630 --> 00:26:59.510
that birds exhibit, but

703
00:26:59.510 --> 00:27:01.110
none of them have become technological

704
00:27:01.110 --> 00:27:02.430
intelligences. And the search for

705
00:27:02.430 --> 00:27:05.150
extraterrestrial intelligence is very much

706
00:27:05.150 --> 00:27:07.190
centred around a technology

707
00:27:08.309 --> 00:27:10.870
that allows civilizations to communicate with

708
00:27:10.870 --> 00:27:13.750
one another. That therefore is based on many

709
00:27:13.750 --> 00:27:15.550
prerequisites that lead to the development of

710
00:27:15.550 --> 00:27:17.390
the ability to broadcast your existence to

711
00:27:17.390 --> 00:27:18.070
the cosmos.

712
00:27:18.470 --> 00:27:20.710
The coal thing's interesting. I mean, I'm not

713
00:27:21.110 --> 00:27:23.440
sufficiently archaeologically

714
00:27:23.520 --> 00:27:26.320
minded to be able to

715
00:27:26.320 --> 00:27:29.040
say with certainty that without coal we

716
00:27:29.040 --> 00:27:30.600
wouldn't have got here. And, uh, the reason

717
00:27:30.600 --> 00:27:32.480
that I express caution on that coal and oil

718
00:27:33.040 --> 00:27:35.440
is that we have things that people burn for

719
00:27:35.440 --> 00:27:37.520
energy that are not coal and oil.

720
00:27:38.239 --> 00:27:40.120
And I think a lot of the smelting that was

721
00:27:40.120 --> 00:27:41.680
done, and I may be wrong on this because I'm

722
00:27:41.680 --> 00:27:43.160
not an archaeologist, I just picked bits up

723
00:27:43.160 --> 00:27:45.280
when my partner's watching Time Tim and

724
00:27:45.280 --> 00:27:46.880
things like that. She loves her archaeology,

725
00:27:46.880 --> 00:27:49.160
so I get a little bit of that as a very thin

726
00:27:49.160 --> 00:27:51.320
veneer. But I think a lot of this times when

727
00:27:51.320 --> 00:27:53.560
people smelted metals, talking about bronze

728
00:27:53.560 --> 00:27:55.900
and iron, they used wood or they used

729
00:27:55.900 --> 00:27:57.980
charcoal, which is a byproduct of burning

730
00:27:57.980 --> 00:27:58.380
wood.

731
00:27:58.620 --> 00:27:59.100
Andrew Dunkley: Yeah.

732
00:27:59.820 --> 00:28:02.780
Jonti Horner: So maybe it would be more challenging without

733
00:28:02.780 --> 00:28:05.540
the easy available energy of fossil

734
00:28:05.540 --> 00:28:07.460
fuels, without the easy available energy of

735
00:28:07.460 --> 00:28:10.379
coal, oil, gas, but it might be that

736
00:28:10.379 --> 00:28:12.060
that wouldn't be an insurmountable hurdle,

737
00:28:12.060 --> 00:28:13.740
but it would result in a different path being

738
00:28:13.740 --> 00:28:16.660
followed. You know, what would we get

739
00:28:16.660 --> 00:28:18.740
in terms of seam power if we were using wood

740
00:28:18.740 --> 00:28:21.260
and if we were using charcoal rather than

741
00:28:21.980 --> 00:28:23.940
other things? Would it lead to an earlier

742
00:28:23.940 --> 00:28:26.020
adoption of renewable energy in the form of

743
00:28:26.020 --> 00:28:28.900
wind power, which was actually being used for

744
00:28:28.900 --> 00:28:30.540
hundreds of years? You go back to Europe and

745
00:28:30.540 --> 00:28:32.820
you see the windmills people use and water

746
00:28:32.820 --> 00:28:35.260
mills peoples use. So I.

747
00:28:35.580 --> 00:28:37.100
I don't know whether.

748
00:28:38.380 --> 00:28:40.420
And this is a problem with all of

749
00:28:40.420 --> 00:28:42.540
astrobiology and it's a problem with a lot of

750
00:28:42.540 --> 00:28:43.820
the stuff that I'll talk about later, about

751
00:28:43.820 --> 00:28:45.500
what makes a planet more suitable or less

752
00:28:45.500 --> 00:28:48.300
suitable. People have this tendency to

753
00:28:48.300 --> 00:28:50.620
find something that is unusual about us.

754
00:28:51.400 --> 00:28:52.920
And there's a lot that's unusual about us. I

755
00:28:52.920 --> 00:28:54.120
mean, there's a lot that's unusual about me.

756
00:28:54.120 --> 00:28:56.400
And I hold my hand up about that. But they

757
00:28:56.400 --> 00:28:59.300
find things that are unusual. And, um,

758
00:28:59.400 --> 00:29:01.320
they say we are, as far as we know, unique in

759
00:29:01.320 --> 00:29:03.320
the cosmos. We are a technologically advanced

760
00:29:03.320 --> 00:29:05.160
civilization able to have this discussion.

761
00:29:06.200 --> 00:29:08.600
There has to be a reason that we're here.

762
00:29:09.240 --> 00:29:12.080
Everything that is unusual quite often gets

763
00:29:12.080 --> 00:29:14.960
held up as could this be the switch? If you

764
00:29:14.960 --> 00:29:17.770
didn't have this, we would not be here. And I

765
00:29:17.770 --> 00:29:19.570
tend to view them not as an on off switch,

766
00:29:19.570 --> 00:29:22.410
but as a slider. They're like. And again, a

767
00:29:22.410 --> 00:29:23.890
gaming analogy would be varying the

768
00:29:23.890 --> 00:29:26.450
difficulty on your game. Some games, it's

769
00:29:26.450 --> 00:29:28.810
very kind of on off, hard mode, easy mode.

770
00:29:28.970 --> 00:29:30.530
Others, particularly some of the role playing

771
00:29:30.530 --> 00:29:33.290
type games people play, have sliders for

772
00:29:33.290 --> 00:29:36.290
everything. And so you can change things to

773
00:29:36.290 --> 00:29:39.210
the nth degree to tweak the challenge

774
00:29:39.210 --> 00:29:41.370
level. And I think all of these things, like

775
00:29:41.370 --> 00:29:44.220
the existence of call that get proposed

776
00:29:44.300 --> 00:29:47.180
as being a boundary, as being

777
00:29:47.180 --> 00:29:48.980
something that would be a block if you didn't

778
00:29:48.980 --> 00:29:51.060
have it, are actually probably more like one

779
00:29:51.060 --> 00:29:52.620
of those sliders. They're things that can

780
00:29:52.620 --> 00:29:55.580
facilitate. But it's really interesting

781
00:29:55.580 --> 00:29:57.660
to discuss them because we don't know how big

782
00:29:57.660 --> 00:29:59.940
a filter they are. We don't know how big a

783
00:29:59.940 --> 00:30:02.340
hurdle they are without digging into it more.

784
00:30:02.340 --> 00:30:04.420
And the more we can suggest these things, the

785
00:30:04.420 --> 00:30:06.180
more we can narrow them down. But ultimately

786
00:30:06.180 --> 00:30:08.740
the only way we can finally test them is when

787
00:30:08.740 --> 00:30:11.100
we get a response to us, when we find

788
00:30:11.420 --> 00:30:14.270
technologically advanced life and

789
00:30:14.270 --> 00:30:16.350
then we learn about their heritage. What path

790
00:30:16.350 --> 00:30:19.030
did they follow? Did they invent fire

791
00:30:19.030 --> 00:30:21.270
before the wheel? Did they invent

792
00:30:21.910 --> 00:30:24.150
modern medicine before fire?

793
00:30:24.790 --> 00:30:27.670
And I've seen there's a fabulous

794
00:30:28.150 --> 00:30:30.150
famous old thread I don't know. It wasn't

795
00:30:30.150 --> 00:30:32.190
from Reddit, predates Reddit, but from one of

796
00:30:32.190 --> 00:30:34.990
the old messaging boards that talks

797
00:30:34.990 --> 00:30:37.750
about humans as the horror

798
00:30:37.750 --> 00:30:40.650
movie monsters of the universe. Because we

799
00:30:40.650 --> 00:30:42.570
always, in science fiction, all the monsters

800
00:30:42.570 --> 00:30:44.530
we face, all the aliens we face, are usually

801
00:30:44.690 --> 00:30:47.010
more something than us. And we overcome

802
00:30:47.010 --> 00:30:49.490
incredible odds to beat them. But this is

803
00:30:49.490 --> 00:30:51.010
taking the other perspective of another

804
00:30:51.010 --> 00:30:52.610
species kind of looking at us and going,

805
00:30:52.610 --> 00:30:54.570
those humans are terrifying. And it's listing

806
00:30:54.570 --> 00:30:55.850
all the ways we are. You know, we're an

807
00:30:55.850 --> 00:30:58.610
exhaustion hunter. We didn't beat things by

808
00:30:58.610 --> 00:31:00.370
speed or anything. We'd follow them until

809
00:31:00.370 --> 00:31:03.290
they died of exhaustion because we

810
00:31:03.290 --> 00:31:05.730
can go longer than they can. Where are you?

811
00:31:05.890 --> 00:31:07.290
They were saying, you know, it's the only

812
00:31:07.290 --> 00:31:09.120
intelligent technological species that, uh,

813
00:31:09.130 --> 00:31:11.300
invented amputation before painkillers.

814
00:31:12.490 --> 00:31:14.250
You know, we've got things like this that are

815
00:31:14.250 --> 00:31:17.090
very bizarre about us. And so that takes

816
00:31:17.090 --> 00:31:19.650
this perspective I've got of these things are

817
00:31:19.650 --> 00:31:22.570
a hurdle. And you develop things, you know

818
00:31:22.730 --> 00:31:24.330
that things are not on an off switch, but

819
00:31:24.330 --> 00:31:26.810
they're more of a slider. And the idea of

820
00:31:27.369 --> 00:31:29.130
will things naturally be developed in the

821
00:31:29.130 --> 00:31:31.370
same order? And turns it around and said,

822
00:31:31.370 --> 00:31:33.170
what would another species think looking at

823
00:31:33.170 --> 00:31:35.730
us? And I always find that really good fun.

824
00:31:35.730 --> 00:31:37.410
And it's effectively leads to the thing that

825
00:31:37.410 --> 00:31:39.690
humans are space orcs and where this

826
00:31:39.690 --> 00:31:42.170
terrible, terrifying, weird little species.

827
00:31:42.490 --> 00:31:44.390
And maybe that's what it'll turn out to be.

828
00:31:45.270 --> 00:31:48.110
Andrew Dunkley: Well, yeah, look, uh, I don't

829
00:31:48.110 --> 00:31:51.030
dispute that because look how we treat each

830
00:31:51.030 --> 00:31:52.790
other or have treated each other,

831
00:31:53.160 --> 00:31:55.750
um, since civilization began,

832
00:31:55.910 --> 00:31:58.910
basically. I don't think you could add up

833
00:31:58.910 --> 00:32:00.710
how many wars we've fought against each

834
00:32:00.710 --> 00:32:03.630
other. I

835
00:32:03.630 --> 00:32:05.230
don't think that would stop. If we found

836
00:32:05.230 --> 00:32:07.230
another intelligent life form, I don't think

837
00:32:07.230 --> 00:32:09.310
we'd go in saying, hi, hey, we're really

838
00:32:09.310 --> 00:32:12.100
nice. I got a feeling we'd, you know,

839
00:32:12.100 --> 00:32:13.740
there'd be a bit of adversarial.

840
00:32:15.100 --> 00:32:17.380
Jonti Horner: It's a really, it is a really interesting

841
00:32:17.380 --> 00:32:17.540
one.

842
00:32:17.540 --> 00:32:19.700
It's one of the things that people factor

843
00:32:19.700 --> 00:32:22.500
into a lot of the discussions about the, the

844
00:32:22.500 --> 00:32:25.020
rights and wrongs of active seti.

845
00:32:25.659 --> 00:32:27.500
So active SETI is sending out a message

846
00:32:27.500 --> 00:32:29.340
saying, hi, we're here. Please talk to us.

847
00:32:29.660 --> 00:32:31.620
Whereas passive SETI is listening for people

848
00:32:31.620 --> 00:32:33.100
saying, please turn neighbours off. We're

849
00:32:33.100 --> 00:32:34.380
sick of seeing it. You know, they're

850
00:32:34.380 --> 00:32:36.380
effectively the two ways you can do seti.

851
00:32:37.250 --> 00:32:39.250
There are, uh, a lot of people in the past

852
00:32:39.250 --> 00:32:41.210
that have argued that active set is a bad

853
00:32:41.210 --> 00:32:42.810
idea because it will attract the wrong kind

854
00:32:42.810 --> 00:32:45.010
of attention. Well, Stephen Hawking certainly

855
00:32:45.010 --> 00:32:47.570
thought that, um, and throwing

856
00:32:47.570 --> 00:32:49.970
noshead. I think the great Mark Commode,

857
00:32:49.970 --> 00:32:52.770
who's a film reviewer in the uk, um, often

858
00:32:52.849 --> 00:32:54.410
says, you know, uh, other opinions are

859
00:32:54.410 --> 00:32:56.050
available. They're wrong, but they are

860
00:32:56.050 --> 00:32:58.610
available. I mean, this, I think, is a case

861
00:32:58.610 --> 00:33:01.530
of that. I think, if any, for me, and I will

862
00:33:01.530 --> 00:33:03.530
admit I'm an optimist, I'm also not exactly

863
00:33:03.530 --> 00:33:06.300
the world's most aggressive person. But for

864
00:33:06.300 --> 00:33:08.420
me, if you have survived as a species for

865
00:33:08.420 --> 00:33:11.100
long enough to be a thriving civilization to

866
00:33:11.100 --> 00:33:12.700
the point of wanting to communicate to the

867
00:33:12.700 --> 00:33:15.340
upscale upstarts that are broadcasting, you

868
00:33:15.340 --> 00:33:16.940
know, Big Brother and all the rest of it, to

869
00:33:16.940 --> 00:33:19.740
the universe, that suggests that to some

870
00:33:19.740 --> 00:33:22.160
degree you've overcome your martiality. Um,

871
00:33:22.260 --> 00:33:25.100
because I think for us to survive to the

872
00:33:25.100 --> 00:33:27.380
point where we're moving out into the stars

873
00:33:27.700 --> 00:33:29.700
will require us not to first wipe ourselves

874
00:33:29.700 --> 00:33:32.490
out. And the more advanced you get, the more

875
00:33:32.490 --> 00:33:35.050
you disperse, probably, fingers crossed,

876
00:33:35.050 --> 00:33:37.770
hopefully, the less likely that becomes. Now,

877
00:33:37.770 --> 00:33:39.130
we look at the world around us today, and

878
00:33:39.130 --> 00:33:40.890
without digging into politics, there's always

879
00:33:40.890 --> 00:33:43.330
something nasty going on. There's many, many

880
00:33:43.330 --> 00:33:45.250
tragedies that are both frontline in the news

881
00:33:45.250 --> 00:33:47.890
and forgotten by the news. But

882
00:33:48.130 --> 00:33:50.530
I saw a great article a few years ago

883
00:33:51.010 --> 00:33:53.250
that was arguing that, you know, when was the

884
00:33:53.250 --> 00:33:54.810
worst time to ever live, and saying that

885
00:33:54.810 --> 00:33:57.290
actually, despite the fact that all this war,

886
00:33:57.290 --> 00:33:59.130
all this aggression, all this violence is so

887
00:33:59.130 --> 00:34:02.010
front and centre, this is actually the safest

888
00:34:02.010 --> 00:34:03.850
era to live in that humanity's ever

889
00:34:03.850 --> 00:34:06.730
experienced. The number of people dying

890
00:34:06.730 --> 00:34:08.810
before their time, dying before they reach

891
00:34:08.810 --> 00:34:11.770
senescence, is lower per thousand people, up

892
00:34:11.770 --> 00:34:13.450
a hundred thousand people than ever before.

893
00:34:14.410 --> 00:34:16.370
You have a much lower chance as an average

894
00:34:16.370 --> 00:34:18.130
person of ever fighting in a war, of ever

895
00:34:18.130 --> 00:34:20.810
being murdered or assaulted. So

896
00:34:20.810 --> 00:34:22.770
we're already moving that way if it doesn't

897
00:34:22.770 --> 00:34:25.050
feel like it. And so to me, with that

898
00:34:25.050 --> 00:34:27.940
optimistic viewpoint, I would like to

899
00:34:27.940 --> 00:34:30.420
think that there is no reason for conflict

900
00:34:30.420 --> 00:34:32.340
and no reason for friction. And I think a lot

901
00:34:32.340 --> 00:34:35.100
of the arguments that humanity's, uh, future

902
00:34:35.500 --> 00:34:38.420
encounters with aliens must by necessity be

903
00:34:38.420 --> 00:34:41.300
violent is telling you more about people than

904
00:34:41.300 --> 00:34:42.860
it's telling you about aliens. Because it's

905
00:34:42.860 --> 00:34:44.900
saying when we look in the mirror, we see the

906
00:34:44.900 --> 00:34:47.220
angry, snarling, tribalist ape rather than

907
00:34:47.220 --> 00:34:49.860
the rational modern human that is a

908
00:34:49.860 --> 00:34:52.460
veneer. On m top. We're still a tribal

909
00:34:52.460 --> 00:34:55.070
species, we're still the product of our

910
00:34:55.070 --> 00:34:57.750
evolution and society is a veneer that we put

911
00:34:57.750 --> 00:35:00.350
on top of that as we learn, um, to be

912
00:35:00.750 --> 00:35:02.470
better, to be the kind of thinking social

913
00:35:02.470 --> 00:35:05.350
app, I guess. And the

914
00:35:05.350 --> 00:35:06.990
evidence is that over time we're getting

915
00:35:06.990 --> 00:35:08.910
better at that. Even though we're now more

916
00:35:08.910 --> 00:35:10.910
capable of killing each other than we ever

917
00:35:10.910 --> 00:35:13.150
were before. Yeah. We're doing it less often.

918
00:35:13.550 --> 00:35:14.430
Andrew Dunkley: Yes, we are.

919
00:35:14.760 --> 00:35:16.550
M. All right, we'll take a quick breather

920
00:35:16.550 --> 00:35:19.310
because I want to get into the, um, the

921
00:35:19.310 --> 00:35:22.230
area of, um, finding this

922
00:35:22.230 --> 00:35:25.110
life beyond our solar system. How, how are we

923
00:35:25.110 --> 00:35:26.650
going to. At where we're going to look and

924
00:35:26.650 --> 00:35:27.690
Jonti Horner: what we've got to look for.

925
00:35:27.690 --> 00:35:30.210
Andrew Dunkley: That's all coming up on this edition of Space

926
00:35:30.210 --> 00:35:30.810
Nuts.

927
00:35:35.210 --> 00:35:36.250
Jonti Horner: Space Nuts.

928
00:35:36.490 --> 00:35:38.730
Andrew Dunkley: So, Jotty, look, lead the way. Where do you

929
00:35:38.730 --> 00:35:40.690
want to go from here? We're gonna, uh, this

930
00:35:40.690 --> 00:35:41.769
is our final segment.

931
00:35:41.850 --> 00:35:44.850
So, um, I suppose if you're going to try and

932
00:35:44.850 --> 00:35:47.210
find life beyond our solar system,

933
00:35:48.160 --> 00:35:50.010
uh, you've got to find the right environment.

934
00:35:50.780 --> 00:35:53.490
Um, you know, rocky planet, habitable zone,

935
00:35:53.490 --> 00:35:54.990
perhaps. Um,

936
00:35:56.270 --> 00:35:58.190
and there's a lot more to it than that. It's

937
00:35:58.190 --> 00:36:00.990
not just, uh, a planet with perhaps liquid

938
00:36:00.990 --> 00:36:03.340
water on its surface. Uh,

939
00:36:04.270 --> 00:36:05.990
you've got to have, I suppose, the right kind

940
00:36:05.990 --> 00:36:08.030
of star. You don't want a red dwarf because

941
00:36:08.030 --> 00:36:10.030
you probably just, you know, get really bad

942
00:36:10.030 --> 00:36:12.910
sunburn. Uh, there's a lot to take

943
00:36:12.910 --> 00:36:13.470
into account.

944
00:36:14.110 --> 00:36:15.950
Jonti Horner: There's a huge amount of depth to it. And I

945
00:36:15.950 --> 00:36:18.150
think, as we saw with the previous episode,

946
00:36:18.150 --> 00:36:20.190
we could have talked another hour and we

947
00:36:20.190 --> 00:36:21.630
could have talked another week. To be honest,

948
00:36:21.630 --> 00:36:23.230
when we're talking about this stuff, one of

949
00:36:23.230 --> 00:36:25.790
the things I, I most adore about

950
00:36:25.790 --> 00:36:28.510
science is the infinite complexity. So you

951
00:36:28.510 --> 00:36:30.190
ask a question, when you get an answer that

952
00:36:30.190 --> 00:36:32.070
isn't it. But you get another 10 questions

953
00:36:32.470 --> 00:36:34.110
and the more you know about a subject, the

954
00:36:34.110 --> 00:36:36.110
more complexity there is. To me, that's just

955
00:36:36.110 --> 00:36:38.750
a wonder. And that's fascinating and this is

956
00:36:38.750 --> 00:36:41.670
a really good example of that. Now, one of my

957
00:36:42.630 --> 00:36:45.190
strongest arguments through my career

958
00:36:46.070 --> 00:36:49.070
has been that we can't just, when we're

959
00:36:49.070 --> 00:36:50.270
trying to think about where we're going to

960
00:36:50.270 --> 00:36:52.910
search for life beyond the solar system, use

961
00:36:52.910 --> 00:36:54.670
a habitable zone. Um, and that's it. You

962
00:36:54.670 --> 00:36:57.630
know, it seems like a lot of coverage and a

963
00:36:57.630 --> 00:36:59.670
lot of papers just go, Earth, like planet

964
00:36:59.670 --> 00:37:00.790
found in the habitable zone.

965
00:37:00.790 --> 00:37:01.150
Andrew Dunkley: Whee.

966
00:37:01.790 --> 00:37:04.110
Jonti Horner: And ah. And um, that's about it. Now the

967
00:37:04.110 --> 00:37:06.870
habitable zone has become a really effective

968
00:37:06.870 --> 00:37:08.750
communication tool in much same way the Drake

969
00:37:08.750 --> 00:37:11.110
Equation has. The Drake Equation is this

970
00:37:11.110 --> 00:37:12.950
fabulous tool with all the sliders where you

971
00:37:12.950 --> 00:37:15.430
can make your own, um, inhabited universe

972
00:37:15.430 --> 00:37:17.510
with lots of few aliens by varying the

973
00:37:17.510 --> 00:37:20.160
variables. The habitable zone has become

974
00:37:20.160 --> 00:37:22.160
another of these catch all kind of

975
00:37:22.160 --> 00:37:24.240
visualisations. And it's born of the idea

976
00:37:24.240 --> 00:37:26.640
that life needs liquid water with the

977
00:37:26.640 --> 00:37:29.640
implicit extension of that, that life needs

978
00:37:29.640 --> 00:37:31.400
liquid water on a planet's surface.

979
00:37:32.440 --> 00:37:34.800
Now, that's initially motivated by the fact

980
00:37:34.800 --> 00:37:36.360
that the Earth is the only place with life

981
00:37:36.440 --> 00:37:38.600
and back when this was being discussed, the

982
00:37:38.600 --> 00:37:41.040
only place with liquid water that we knew. So

983
00:37:41.040 --> 00:37:42.720
therefore it was natural to say you need

984
00:37:42.720 --> 00:37:45.060
surface liquid water. As we discussed

985
00:37:45.060 --> 00:37:46.460
earlier, there are plenty of places in the

986
00:37:46.460 --> 00:37:48.860
solar system that do not have liquid water on

987
00:37:48.860 --> 00:37:50.860
the surface, but do have it underneath.

988
00:37:50.860 --> 00:37:53.340
They've got soft centres. But the habitable

989
00:37:53.340 --> 00:37:55.980
zone, um, says you need liquid water

990
00:37:56.460 --> 00:37:58.700
on the surface of a planet for that planet to

991
00:37:58.700 --> 00:38:00.259
be considered suitable for life to be

992
00:38:00.259 --> 00:38:03.140
habitable. Now, that isn't entirely

993
00:38:03.140 --> 00:38:05.700
true, but for the purposes of this, it's

994
00:38:05.700 --> 00:38:08.620
still useful because life buried beneath

995
00:38:08.620 --> 00:38:10.860
ice is so hard to find that we can't find it

996
00:38:10.860 --> 00:38:12.380
in our own solar system. Because the ice is

997
00:38:12.380 --> 00:38:14.430
in the way, we wouldn't have a chance to run

998
00:38:14.430 --> 00:38:16.790
planets around other stars. So even though I

999
00:38:16.790 --> 00:38:18.230
think the habitable zone is a bigger

1000
00:38:18.230 --> 00:38:20.110
oversimplification, I see merit to it,

1001
00:38:20.110 --> 00:38:22.670
because life on a planet's surface with

1002
00:38:22.830 --> 00:38:25.550
only atmosphere above is much more likely to

1003
00:38:25.550 --> 00:38:27.350
be detectable than life buried deep in the

1004
00:38:27.350 --> 00:38:29.310
interior. So, fair enough, we'll go with it.

1005
00:38:29.710 --> 00:38:31.630
The idea of the habitable zone, though, is

1006
00:38:31.870 --> 00:38:33.630
that the closer you are to a star, the hotter

1007
00:38:33.630 --> 00:38:35.670
you are, the further away you are, the cooler

1008
00:38:35.670 --> 00:38:37.670
you are. And just like Goldilocks and the

1009
00:38:37.670 --> 00:38:39.030
Three Bears, which is why it's often called

1010
00:38:39.030 --> 00:38:40.630
the Goldilocks Zone, there's a place where

1011
00:38:40.630 --> 00:38:42.470
it's just right, it's not too hot, not too

1012
00:38:42.470 --> 00:38:44.780
cold, and therefore there could be liquid

1013
00:38:44.780 --> 00:38:47.260
water on the surface of the planet. Now, a

1014
00:38:47.260 --> 00:38:49.100
lot of the time when people say a planet is

1015
00:38:49.100 --> 00:38:52.100
in the habitable zone, um, that's

1016
00:38:52.660 --> 00:38:55.500
often taken as meaning that planet could and

1017
00:38:55.500 --> 00:38:57.260
potentially will have liquid water on the

1018
00:38:57.260 --> 00:38:59.460
surface. But actually, what it's saying is,

1019
00:38:59.700 --> 00:39:02.420
if you took the Earth as the Earth is today,

1020
00:39:02.900 --> 00:39:05.300
and put it in that system, would it still

1021
00:39:05.300 --> 00:39:06.780
look like the Earth? Would it have liquid

1022
00:39:06.780 --> 00:39:09.110
water on its surface? Now, now

1023
00:39:09.430 --> 00:39:11.710
we've extended a bit beyond that. There are a

1024
00:39:11.710 --> 00:39:13.390
couple of fabulous papers a bit more than a

1025
00:39:13.390 --> 00:39:15.480
decade old now that set. What are our very,

1026
00:39:15.480 --> 00:39:17.790
uh, contemporary scientific, mathematical

1027
00:39:17.790 --> 00:39:19.910
definitions of the habitable zone, um, that

1028
00:39:19.910 --> 00:39:22.470
people use for their papers, and they take

1029
00:39:22.470 --> 00:39:24.710
the flux from the star, take into account the

1030
00:39:24.710 --> 00:39:27.230
different colours of the stars and, um, there

1031
00:39:27.230 --> 00:39:29.150
are two versions. There's the optimistic and

1032
00:39:29.150 --> 00:39:31.470
conservative versions, where the

1033
00:39:31.470 --> 00:39:34.070
optimistic version is a wider set of

1034
00:39:34.070 --> 00:39:35.910
distances and the conservative version is a

1035
00:39:35.910 --> 00:39:38.270
smaller set of distances, but it effectively

1036
00:39:38.270 --> 00:39:40.890
uses Venus and Mars as A roughinger edge in

1037
00:39:40.890 --> 00:39:42.810
our solar system and then scales that window

1038
00:39:42.810 --> 00:39:44.770
up and down depending on the kind of star

1039
00:39:44.770 --> 00:39:47.330
you're around. But that illustrates

1040
00:39:47.410 --> 00:39:49.970
immediately that this is an

1041
00:39:49.970 --> 00:39:51.850
oversimplification, because you can do a

1042
00:39:51.850 --> 00:39:53.850
thought experiment. Let's take our solar

1043
00:39:53.850 --> 00:39:56.689
system. Venus is way too hot, Mars is way too

1044
00:39:56.689 --> 00:39:58.450
cold and the Earth is just right. All well

1045
00:39:58.450 --> 00:40:01.330
and good. Swap the Earth. Sorry, swap Mars

1046
00:40:01.330 --> 00:40:03.690
and Venus around. If you put Venus where Mars

1047
00:40:03.690 --> 00:40:06.090
is, Venus's thick atmosphere and greenhouse

1048
00:40:06.090 --> 00:40:07.610
effect would mean it'd be warming up liquid

1049
00:40:07.610 --> 00:40:09.250
water on the surface. It wouldn't have cooled

1050
00:40:09.250 --> 00:40:11.770
as much as Mars. So Venus will be

1051
00:40:12.010 --> 00:40:14.890
habitable on the surface, outside the

1052
00:40:14.890 --> 00:40:17.090
habitable zone. Um, if you put m Mars, where

1053
00:40:17.090 --> 00:40:18.970
Venus is, with its very thin and tenuous

1054
00:40:18.970 --> 00:40:21.890
atmosphere, it doesn't have much greenhouse

1055
00:40:21.890 --> 00:40:24.250
effect at all. Mars would potentially still

1056
00:40:24.250 --> 00:40:27.050
be habitable where Venus is, when

1057
00:40:27.050 --> 00:40:29.770
Venus isn't. And so that's immediately

1058
00:40:29.770 --> 00:40:31.370
pointing that the storey is actually

1059
00:40:31.370 --> 00:40:33.850
significantly more complex. Yeah. That

1060
00:40:34.410 --> 00:40:37.410
you can't just say, let's calculate the

1061
00:40:37.410 --> 00:40:38.930
habitable zone, let's calculate the

1062
00:40:38.930 --> 00:40:41.450
equilibrium temperature on a planet, which is

1063
00:40:41.450 --> 00:40:44.250
a temperature it would have if it didn't have

1064
00:40:44.250 --> 00:40:46.370
a greenhouse effect, that it was a certain

1065
00:40:46.370 --> 00:40:48.570
reflectivity and it was in equilibrium with

1066
00:40:48.570 --> 00:40:50.450
the light coming in and light coming out. And

1067
00:40:50.450 --> 00:40:52.530
if that temperature is from about minus 20

1068
00:40:52.530 --> 00:40:54.850
upwards, it's probably warm enough for water

1069
00:40:54.850 --> 00:40:55.970
because, well, you'll have a bit of an

1070
00:40:55.970 --> 00:40:58.410
atmosphere. To me, that's never been enough.

1071
00:40:58.490 --> 00:41:00.930
Now, the reason it's really important, at

1072
00:41:00.930 --> 00:41:02.940
least from my perspective, is that, uh,

1073
00:41:03.010 --> 00:41:05.250
finding planets is hard. We'll talk about

1074
00:41:05.250 --> 00:41:08.250
that in another episode. But once you find

1075
00:41:08.250 --> 00:41:11.130
the first of something, astronomy, history

1076
00:41:11.130 --> 00:41:12.850
and probably every other form of scientific

1077
00:41:12.850 --> 00:41:14.450
endeavour history tells us finding the first

1078
00:41:14.450 --> 00:41:16.490
of something is hard. But once you've got

1079
00:41:16.490 --> 00:41:18.210
one, you quickly find more and more as your

1080
00:41:18.210 --> 00:41:20.970
technology gets better. Finding evidence of

1081
00:41:20.970 --> 00:41:23.730
life on a planet that is similar to the Earth

1082
00:41:24.210 --> 00:41:26.650
is fundamentally at least an order of

1083
00:41:26.650 --> 00:41:29.040
magnitude, if not more harder than finding

1084
00:41:29.040 --> 00:41:31.400
that planet was. So it'll take time for our

1085
00:41:31.400 --> 00:41:33.440
technology to get good enough to search

1086
00:41:33.680 --> 00:41:36.480
comfortably for life elsewhere. So initially

1087
00:41:36.480 --> 00:41:38.400
that search is going to be very restricted

1088
00:41:38.400 --> 00:41:40.840
because we've got limited resources. So

1089
00:41:40.840 --> 00:41:42.320
you're only going to be able to look at a few

1090
00:41:42.320 --> 00:41:45.120
planets aggressively at first, to try and

1091
00:41:45.120 --> 00:41:47.120
tease out any indication of life.

1092
00:41:47.920 --> 00:41:49.400
But you're going to have loads to choose

1093
00:41:49.400 --> 00:41:52.120
from. How should you choose? Well, to me, it

1094
00:41:52.120 --> 00:41:53.520
can't just be the habitable zone.

1095
00:41:56.090 --> 00:41:58.900
Andrew Dunkley: Yeah, that's a valid point. Um,

1096
00:41:59.370 --> 00:42:01.930
and we've reached a point where we've found

1097
00:42:02.010 --> 00:42:04.850
thousands upon thousands of Exoplanets and

1098
00:42:04.850 --> 00:42:06.770
counting like we haven't stopped. We're

1099
00:42:06.770 --> 00:42:09.490
finding them more and more and more often of

1100
00:42:09.490 --> 00:42:12.260
all different shapes of, uh, sizes. Um,

1101
00:42:13.930 --> 00:42:16.250
some rocky planets, uh, they've been harder

1102
00:42:16.250 --> 00:42:18.450
to find because they're usually much smaller

1103
00:42:18.450 --> 00:42:21.130
and don't sort of indicate

1104
00:42:21.130 --> 00:42:23.090
themselves like a gas giant does.

1105
00:42:24.050 --> 00:42:26.540
But we're getting better at finding rocky,

1106
00:42:26.540 --> 00:42:27.410
uh, planets.

1107
00:42:27.880 --> 00:42:30.770
Um, I suppose the big

1108
00:42:30.770 --> 00:42:33.570
question is, given how much we are finding,

1109
00:42:34.050 --> 00:42:36.770
how do you identify prime targets for life?

1110
00:42:37.490 --> 00:42:40.090
Jonti Horner: Yeah, and that is what the paper that I put

1111
00:42:40.090 --> 00:42:42.610
together with Barry Jones back in 2010 was

1112
00:42:42.610 --> 00:42:45.370
all about. So Barry was a very dear friend of

1113
00:42:45.370 --> 00:42:47.330
mine. He was my boss when I moved to the open

1114
00:42:47.330 --> 00:42:49.590
University from 2000 and 22,006 to 2009. I

1115
00:42:49.590 --> 00:42:50.830
think he knew Fred Watson very well as well.

1116
00:42:50.830 --> 00:42:52.870
So you can always mention to Fred Watson that

1117
00:42:52.870 --> 00:42:54.910
we talked about Barry. I started work at the

1118
00:42:54.910 --> 00:42:57.550
Open University in 2006 on the day Barry was

1119
00:42:57.550 --> 00:42:59.350
forced to retire by the government because

1120
00:42:59.350 --> 00:43:02.110
he'd hit 67. So he hired me and promptly

1121
00:43:02.110 --> 00:43:04.789
retired. But, um, he kept working anyway as

1122
00:43:04.950 --> 00:43:07.950
emeritus professor and Barry and I

1123
00:43:07.950 --> 00:43:09.790
did a lot of work on this during my time that

1124
00:43:09.790 --> 00:43:11.470
Barry unfortunately passed away a little bit

1125
00:43:11.470 --> 00:43:13.510
more than a decade ago. So he's fondly

1126
00:43:13.510 --> 00:43:15.880
remembered. I organise a, an award in the UK

1127
00:43:15.880 --> 00:43:18.880
in his memory every couple of years. What

1128
00:43:18.880 --> 00:43:21.640
we did in this 2010 paper was

1129
00:43:22.280 --> 00:43:24.480
to essentially have the thought process we

1130
00:43:24.480 --> 00:43:27.200
just outlined. So we're going to have a huge

1131
00:43:27.200 --> 00:43:29.920
number of potential exo Earths, planets that

1132
00:43:29.920 --> 00:43:32.480
could potentially be Earth like that could be

1133
00:43:32.480 --> 00:43:35.080
places to look for life. But we're only going

1134
00:43:35.080 --> 00:43:36.640
to be able to search a, ah, handful of them

1135
00:43:36.640 --> 00:43:39.320
initially. So what should we do to select the

1136
00:43:39.320 --> 00:43:41.960
best target? Now obviously the

1137
00:43:41.960 --> 00:43:44.320
closer the planet's host star is to the solar

1138
00:43:44.320 --> 00:43:46.280
system, the easier the observations will be.

1139
00:43:46.840 --> 00:43:49.080
That's just a fundamental thing of if you're

1140
00:43:49.080 --> 00:43:50.920
twice as far away, we only receive a quarter

1141
00:43:50.920 --> 00:43:53.200
as much light from you. But also if you're

1142
00:43:53.200 --> 00:43:55.200
twice as far away, the separation between the

1143
00:43:55.200 --> 00:43:57.240
planet and the star on the sky will be half

1144
00:43:57.240 --> 00:44:00.040
as much because the angle gets

1145
00:44:00.040 --> 00:44:01.800
smaller the further away you go. Essentially

1146
00:44:02.040 --> 00:44:03.840
we, uh, will want targets that are far enough

1147
00:44:03.840 --> 00:44:05.400
from the star in the sky that with future

1148
00:44:05.400 --> 00:44:06.880
missions like potentially the Habitable

1149
00:44:06.880 --> 00:44:09.370
Worlds Observatory, we can separate the light

1150
00:44:09.370 --> 00:44:11.050
from the planet from the light from the star.

1151
00:44:11.850 --> 00:44:14.050
So probably even more important than the

1152
00:44:14.050 --> 00:44:16.650
habitable zone, um, is this proximity thing.

1153
00:44:16.890 --> 00:44:19.650
The planets in the main found by the Kepler

1154
00:44:19.650 --> 00:44:21.850
space telescope won't be suitable for this

1155
00:44:21.850 --> 00:44:23.810
search because they're mainly very far from

1156
00:44:23.810 --> 00:44:26.290
the sun. And so therefore they'll be very

1157
00:44:26.290 --> 00:44:27.850
hard to study. We want to look locally,

1158
00:44:27.850 --> 00:44:30.570
that's a given. But

1159
00:44:30.730 --> 00:44:32.930
we want to look for places where there is the

1160
00:44:32.930 --> 00:44:34.730
possibility of liquid water on the surface

1161
00:44:35.390 --> 00:44:37.190
because that means that the life will be in

1162
00:44:37.190 --> 00:44:38.590
contact with the atmosphere and that might

1163
00:44:38.590 --> 00:44:40.270
generate a signature we can detect in the

1164
00:44:40.270 --> 00:44:42.230
atmosphere. And that's where the habitable

1165
00:44:42.230 --> 00:44:45.030
zone comes from. But there's actually much

1166
00:44:45.030 --> 00:44:47.190
more to it than that, I think, and I'm far

1167
00:44:47.190 --> 00:44:48.990
from able to give an exhaustive list because

1168
00:44:48.990 --> 00:44:51.029
I'm not an expert in, uh, all areas of

1169
00:44:51.029 --> 00:44:53.830
astronomy. But we decided to put together a

1170
00:44:53.830 --> 00:44:56.510
review paper which, about 32

1171
00:44:56.750 --> 00:44:59.230
pages long, probably a little bit outdated

1172
00:44:59.230 --> 00:45:01.810
now because science has moved forward, but

1173
00:45:01.810 --> 00:45:04.490
was saying, effectively you can't just use a

1174
00:45:04.490 --> 00:45:07.410
habitable zone. We need to think about

1175
00:45:07.490 --> 00:45:09.250
all of the different factors that can

1176
00:45:09.250 --> 00:45:10.890
contribute to make a planet more or less

1177
00:45:10.890 --> 00:45:13.370
suitable for life. Now, many of these have

1178
00:45:13.370 --> 00:45:15.090
been in the past suggested as that on off

1179
00:45:15.090 --> 00:45:17.010
switch. And I do think that they're more

1180
00:45:17.250 --> 00:45:18.770
sliders, like the numbers in the Drake

1181
00:45:18.770 --> 00:45:21.410
equation or sliders on a mixing desk. But

1182
00:45:21.410 --> 00:45:22.850
there are a lot of different things that have

1183
00:45:22.850 --> 00:45:24.690
been suggested and as I dug into the paper,

1184
00:45:25.090 --> 00:45:26.810
there were even more than I thought of. You

1185
00:45:26.810 --> 00:45:29.190
can broadly break them down m into four

1186
00:45:29.190 --> 00:45:32.070
areas. The first is galactic influences.

1187
00:45:32.870 --> 00:45:35.590
So the impact of the galaxy itself, where you

1188
00:45:35.590 --> 00:45:37.510
are in the galaxy, stuff like that, you've

1189
00:45:37.510 --> 00:45:39.550
then got stellar influences, so the role of

1190
00:45:39.550 --> 00:45:42.110
the star. You've got the planetary system and

1191
00:45:42.110 --> 00:45:44.030
then you've got the planet itself. So they're

1192
00:45:44.030 --> 00:45:46.750
the kind of four broad areas, the

1193
00:45:46.750 --> 00:45:49.150
galactic influences. One is probably the

1194
00:45:49.150 --> 00:45:50.790
least useful and the least well constrained.

1195
00:45:50.790 --> 00:45:53.230
But the idea of the galactic influence is

1196
00:45:53.230 --> 00:45:55.450
tied a bit to a theory that's been put

1197
00:45:55.450 --> 00:45:57.170
forward by a few people called the Galactic

1198
00:45:57.170 --> 00:46:00.050
Habitable Zone. It's an idea that

1199
00:46:00.930 --> 00:46:03.130
ties back to the origin of stars and planets

1200
00:46:03.130 --> 00:46:05.210
and also to the dangers that are experienced

1201
00:46:05.210 --> 00:46:07.770
because of your environment. The idea that as

1202
00:46:07.770 --> 00:46:09.730
time goes on, the universe is becoming more

1203
00:46:09.730 --> 00:46:12.730
metal rich and by that I mean enriched in

1204
00:46:12.730 --> 00:46:14.290
everything other than hydrogen and helium,

1205
00:46:14.290 --> 00:46:16.370
because generations of stars run their

1206
00:46:16.370 --> 00:46:18.250
furnaces and turn the light elements to the

1207
00:46:18.250 --> 00:46:20.020
heavy ones and put them back into the cosmos.

1208
00:46:20.650 --> 00:46:22.290
You need a certain amount of heavy elements

1209
00:46:22.290 --> 00:46:24.370
to form planets like the Earth and to have

1210
00:46:24.370 --> 00:46:26.490
the carbon, nitrogen, phosphorus for life.

1211
00:46:27.690 --> 00:46:29.690
So as time goes on, the universe getting more

1212
00:46:29.690 --> 00:46:32.010
enriched is a good thing. But there's also

1213
00:46:32.010 --> 00:46:34.290
possibilities that too much enrichment will

1214
00:46:34.290 --> 00:46:36.009
change the chemistry or it will make planet

1215
00:46:36.009 --> 00:46:38.570
formation too easy. There's all sorts there,

1216
00:46:38.730 --> 00:46:40.850
so you might have a sweet spot from that side

1217
00:46:40.850 --> 00:46:43.770
of things. Now in the middle of the galaxy,

1218
00:46:43.930 --> 00:46:46.090
star formation occurs at a more rapid pace

1219
00:46:46.090 --> 00:46:48.660
and stars live and die quicker. So you get

1220
00:46:48.980 --> 00:46:51.820
faster change in the abundance of

1221
00:46:51.820 --> 00:46:54.140
materials. So you can imagine we have this

1222
00:46:54.140 --> 00:46:56.060
concept in astronomy called metallicity,

1223
00:46:56.060 --> 00:46:58.540
which is the amount. It's usually measured in

1224
00:46:58.540 --> 00:47:00.540
the amount of hydrogen compared to the amount

1225
00:47:00.540 --> 00:47:03.220
of iron in a star. And that gives you a

1226
00:47:03.220 --> 00:47:05.820
number on a logarithmic scale. And that is an

1227
00:47:05.820 --> 00:47:08.300
approximation to when the star formed and how

1228
00:47:08.300 --> 00:47:10.460
enriched the world was at the time. And as

1229
00:47:10.460 --> 00:47:12.060
time goes on, things get more and more metal

1230
00:47:12.060 --> 00:47:14.700
rich within our galaxy. You'd expect there to

1231
00:47:14.700 --> 00:47:16.420
be a gradient in this, so the things near the

1232
00:47:16.420 --> 00:47:18.340
middle will be much more enriched in heavy

1233
00:47:18.340 --> 00:47:19.770
elements of things, things near the outer

1234
00:47:19.770 --> 00:47:21.890
edge. And there's probably sweet spot in the

1235
00:47:21.890 --> 00:47:24.330
middle that moves outwards over time where

1236
00:47:24.330 --> 00:47:26.100
conditions to form planets like the Earth,

1237
00:47:26.100 --> 00:47:27.850
uh, and planetary systems like the solar

1238
00:47:27.850 --> 00:47:30.570
system are perfect. So that's part of the

1239
00:47:30.570 --> 00:47:32.290
galactic habitable zone idea. But the other

1240
00:47:32.290 --> 00:47:35.049
idea is that if you're too close in and the

1241
00:47:35.049 --> 00:47:37.610
stellar density is too high, eventually the

1242
00:47:37.610 --> 00:47:39.290
stellar density gets, uh, so high that the

1243
00:47:39.290 --> 00:47:41.370
likelihood of life being exterminated by

1244
00:47:41.370 --> 00:47:43.970
nearby supernovae or planetary systems being

1245
00:47:43.970 --> 00:47:46.400
stripped and disrupted becomes too high. So

1246
00:47:46.400 --> 00:47:48.600
there's always been this idea that location

1247
00:47:48.600 --> 00:47:50.480
within the galaxy is important.

1248
00:47:51.520 --> 00:47:54.400
The challenge to that is twofold. Firstly,

1249
00:47:54.560 --> 00:47:56.560
the proximity argument. We're gonna have to

1250
00:47:56.560 --> 00:47:59.200
look at stars that are very nearby, which are

1251
00:47:59.200 --> 00:48:00.600
all at the same distance from in the middle

1252
00:48:00.600 --> 00:48:03.360
of the galaxy as we are. So where you are in

1253
00:48:03.360 --> 00:48:06.320
the galaxy won't realistically impact this

1254
00:48:06.320 --> 00:48:07.560
search because we're going to be looking

1255
00:48:07.560 --> 00:48:10.120
locally. The other thing so is that stars

1256
00:48:10.120 --> 00:48:12.460
have a huge degree of mobility. There was a

1257
00:48:12.460 --> 00:48:14.980
recent storey talking about finding solar

1258
00:48:14.980 --> 00:48:16.980
twin stars that have the same chemistry as

1259
00:48:16.980 --> 00:48:19.180
the sun, that may have formed with the sun,

1260
00:48:19.660 --> 00:48:22.380
and a suggestion that the sun and other stars

1261
00:48:22.380 --> 00:48:24.460
may have formed as much as 10,000 light years

1262
00:48:24.460 --> 00:48:26.020
nearer the middle of the galaxy than we are

1263
00:48:26.020 --> 00:48:28.300
now. Stars are getting scattered inwards and

1264
00:48:28.300 --> 00:48:30.860
outwards. So seeing a star here now doesn't

1265
00:48:30.940 --> 00:48:32.940
imply that it's always been here.

1266
00:48:33.180 --> 00:48:33.620
Andrew Dunkley: Yeah.

1267
00:48:33.620 --> 00:48:36.220
Jonti Horner: So the galactic influences, I'm not going to

1268
00:48:36.220 --> 00:48:38.260
go into really any more than that, but it's

1269
00:48:38.260 --> 00:48:40.110
worth knowing that they're there, there. It's

1270
00:48:40.110 --> 00:48:41.430
worth knowing that it's a point of discussion

1271
00:48:41.430 --> 00:48:42.950
and that there is good research going on

1272
00:48:42.950 --> 00:48:45.270
about this. It's really interesting area, but

1273
00:48:45.270 --> 00:48:47.470
it doesn't, I think, impact our initial

1274
00:48:47.470 --> 00:48:49.830
search for life, because we're going to be

1275
00:48:50.870 --> 00:48:52.910
searching our local area. So it's a bit like

1276
00:48:52.910 --> 00:48:54.750
me saying, I Want to search for signs of life

1277
00:48:54.750 --> 00:48:57.270
on Earth, It's a lot easier for me to search

1278
00:48:57.350 --> 00:49:00.070
in Kingstorp, where I live, than to search in

1279
00:49:00.070 --> 00:49:02.830
Mumbai or in London. Places like this,

1280
00:49:02.830 --> 00:49:05.230
you've got to look locally. Now, talking

1281
00:49:05.230 --> 00:49:06.870
about that, you know, what would I expect to

1282
00:49:06.870 --> 00:49:09.420
find? I'm, you know, the people in Kingsop

1283
00:49:09.580 --> 00:49:11.500
have not all, but many of them have a similar

1284
00:49:11.500 --> 00:49:13.220
background to me, formed in similar ways with

1285
00:49:13.220 --> 00:49:16.060
similar cultural, the rest of it. So

1286
00:49:16.060 --> 00:49:18.660
this is not a great analogy, I

1287
00:49:18.660 --> 00:49:20.780
admit, but we've got to look locally. So the

1288
00:49:20.780 --> 00:49:22.220
galactic influencer stuff is

1289
00:49:23.339 --> 00:49:26.060
interesting, but I wouldn't say it

1290
00:49:26.060 --> 00:49:28.820
is a big factor, but it's worth. Okay, I

1291
00:49:28.820 --> 00:49:29.180
guess.

1292
00:49:30.220 --> 00:49:31.580
Andrew Dunkley: So that leads us on to,

1293
00:49:32.230 --> 00:49:35.220
um, I don't know, finding the right

1294
00:49:35.220 --> 00:49:38.100
targets. Uh, and, and if we do find

1295
00:49:38.100 --> 00:49:41.100
those targets, what, what do

1296
00:49:41.100 --> 00:49:43.940
we do then to look for potential

1297
00:49:43.940 --> 00:49:45.220
life on those targets?

1298
00:49:45.300 --> 00:49:47.100
Jonti Horner: Absolutely. And that's a very hard question.

1299
00:49:47.100 --> 00:49:48.939
Now, in terms of finding the right targets,

1300
00:49:48.939 --> 00:49:50.580
there's a lot that comes into it from the

1301
00:49:50.580 --> 00:49:52.740
star itself. Now,

1302
00:49:53.540 --> 00:49:56.100
stars live very long lives.

1303
00:49:56.900 --> 00:49:58.780
First question then is, how old is a star?

1304
00:49:58.780 --> 00:50:00.460
Now, if we look at life on Earth, the oldest

1305
00:50:00.460 --> 00:50:02.990
star fossils on Earth that are widely

1306
00:50:02.990 --> 00:50:04.750
accepted are about three and a half thousand

1307
00:50:04.750 --> 00:50:06.870
million years old, are in the Pilbara, which

1308
00:50:06.870 --> 00:50:08.700
is about a billion years after the Earth, uh,

1309
00:50:08.790 --> 00:50:10.750
formed. There are some that are older that

1310
00:50:10.750 --> 00:50:13.030
are still controversial, possibly as old as 4

1311
00:50:13.030 --> 00:50:14.630
billion years. But if we take the 3 1/2

1312
00:50:14.630 --> 00:50:17.630
billion years as a threshold and we do what

1313
00:50:17.630 --> 00:50:19.110
we're doing with the liquid water thing, and

1314
00:50:19.110 --> 00:50:20.910
we say we expect life to follow a similar

1315
00:50:20.910 --> 00:50:23.590
path, to us, the fact that it took a billion

1316
00:50:23.590 --> 00:50:25.310
years for life to get established enough to

1317
00:50:25.310 --> 00:50:27.680
leave fossils we could find possibly means

1318
00:50:27.680 --> 00:50:29.240
that it might have taken a similar length of

1319
00:50:29.240 --> 00:50:30.880
time for that life to modify its environment

1320
00:50:30.880 --> 00:50:33.200
enough to be detectable from elsewhere. So we

1321
00:50:33.200 --> 00:50:35.560
can put an arbitrary kind of timer here

1322
00:50:35.560 --> 00:50:38.280
saying that any planetary system younger

1323
00:50:38.280 --> 00:50:41.040
than, say, a billion years may have planets

1324
00:50:41.040 --> 00:50:42.479
that are suitable for life, but that life

1325
00:50:42.479 --> 00:50:44.320
might have not had enough time to get

1326
00:50:44.320 --> 00:50:47.320
established yet. So that might

1327
00:50:47.640 --> 00:50:50.200
immediately say that's not as good a place to

1328
00:50:50.200 --> 00:50:51.800
look as a star that is more like the edge of

1329
00:50:51.800 --> 00:50:54.010
the sun, while life's had 4 billion years to

1330
00:50:54.010 --> 00:50:56.930
get going. Now, tied to that is

1331
00:50:56.930 --> 00:50:59.490
the fact that the lives of stars are very

1332
00:50:59.490 --> 00:51:01.850
dependent on the mass. So the more massive a

1333
00:51:01.850 --> 00:51:03.410
star is, the brighter it shines, but the

1334
00:51:03.410 --> 00:51:06.370
shorter its life is. And at a very rough

1335
00:51:06.450 --> 00:51:08.289
level, this number varies a little bit

1336
00:51:08.289 --> 00:51:09.530
depending on the mass of the star. But

1337
00:51:09.530 --> 00:51:12.050
typically, the luminosity of a star Is

1338
00:51:12.050 --> 00:51:14.050
proportional to its mass to the power four.

1339
00:51:14.370 --> 00:51:16.170
So if you've got a star that is 10 times the

1340
00:51:16.170 --> 00:51:18.050
mass of the sun, it will be roughly 10,000

1341
00:51:18.130 --> 00:51:20.740
times brighter than the sun. But these

1342
00:51:20.740 --> 00:51:22.620
stars are burning their own material. They're

1343
00:51:22.620 --> 00:51:24.100
turning hydrogen to helium, and they're made

1344
00:51:24.100 --> 00:51:26.500
of hydrogen. So a star that is 10 times the

1345
00:51:26.500 --> 00:51:28.820
mass of the sun will only have 10 times as

1346
00:51:28.820 --> 00:51:31.060
much fuel as the sun, but it's burning that

1347
00:51:31.060 --> 00:51:33.700
fuel 10,000 times quicker, which means it'll

1348
00:51:33.700 --> 00:51:36.100
run out a lot quicker. And what that means is

1349
00:51:36.100 --> 00:51:37.620
that, uh, the more massive a star is, the

1350
00:51:37.620 --> 00:51:40.540
longer, the shorter its life will be. And the

1351
00:51:40.540 --> 00:51:42.180
less massive a star is, the longer its life

1352
00:51:42.180 --> 00:51:45.020
will be. That means that beyond

1353
00:51:45.020 --> 00:51:47.140
a certain, uh, stellar mass, the star will

1354
00:51:47.140 --> 00:51:50.070
die before that billion year cutoff. So we

1355
00:51:50.070 --> 00:51:52.110
can probably rule out the most massive stars.

1356
00:51:52.190 --> 00:51:54.350
They'll just live fast, die young, and it's

1357
00:51:54.350 --> 00:51:55.830
unlikely that life will get well enough

1358
00:51:55.830 --> 00:51:58.390
established. On the flip side, the dim little

1359
00:51:58.390 --> 00:52:00.230
red dwarfs will just go forever. You know,

1360
00:52:00.230 --> 00:52:02.030
Proxima Centauri will still be trundling

1361
00:52:02.030 --> 00:52:03.950
along in a trillion years when we're a decent

1362
00:52:03.950 --> 00:52:06.230
memory. So they might be a good place to

1363
00:52:06.230 --> 00:52:08.580
look. The challenge there though is, uh,

1364
00:52:08.580 --> 00:52:11.190
those stars are, uh, quite active quite

1365
00:52:11.190 --> 00:52:13.990
often. And um, to be in the habitable zone

1366
00:52:13.990 --> 00:52:15.390
around them, you've got to be very close in

1367
00:52:15.390 --> 00:52:16.750
because they're called little embers. You've

1368
00:52:16.750 --> 00:52:18.810
got to snuggle up to the fire. So there's a

1369
00:52:18.810 --> 00:52:20.730
lot of discussion about the fact that m dwarf

1370
00:52:20.730 --> 00:52:22.930
planets, planets around these coolest,

1371
00:52:22.930 --> 00:52:25.210
smallest stars are probably not ideal places

1372
00:52:25.210 --> 00:52:27.650
to look for knife initially, few reasons. One

1373
00:52:27.650 --> 00:52:29.850
is that activity and a lot of discussions

1374
00:52:29.850 --> 00:52:31.530
that the activity of red dwarfs when they're

1375
00:52:31.530 --> 00:52:33.450
young could scour a planet's atmosphere away.

1376
00:52:33.610 --> 00:52:35.290
And that seems to have possibly been backed

1377
00:52:35.290 --> 00:52:38.130
up with the Trappist 1 planets that all seem

1378
00:52:38.130 --> 00:52:41.130
to be airless worlds. The other is that those

1379
00:52:41.130 --> 00:52:43.570
planets, if they are close enough in to be

1380
00:52:43.570 --> 00:52:45.130
warm enough for liquid water on the surface,

1381
00:52:45.130 --> 00:52:47.370
would have to be tidally locked like the moon

1382
00:52:47.370 --> 00:52:49.640
is to the Earth. Which means they'll keep one

1383
00:52:49.640 --> 00:52:51.360
face permanently pointed towards the star and

1384
00:52:51.360 --> 00:52:54.160
the other permanently away, which may make it

1385
00:52:54.160 --> 00:52:56.000
harder to look for life on them. It might be

1386
00:52:56.000 --> 00:52:57.760
the case, uh, any life would be on the

1387
00:52:57.760 --> 00:52:59.880
sunward side. And that's kind of hard to

1388
00:52:59.880 --> 00:53:01.320
observe because when that side is best

1389
00:53:01.320 --> 00:53:04.119
presented to us, it's near the star. So

1390
00:53:04.119 --> 00:53:06.280
that's challenging. Another thing that

1391
00:53:06.280 --> 00:53:08.400
factors into it ties into something called

1392
00:53:08.400 --> 00:53:10.720
the faint early sun paradox on Earth.

1393
00:53:11.360 --> 00:53:13.960
The lives of

1394
00:53:13.960 --> 00:53:16.120
stars. They shine brightly, their brightness

1395
00:53:16.120 --> 00:53:18.270
Is measured good compared to their mass, but

1396
00:53:18.270 --> 00:53:20.590
their brightness increases with time. Stars

1397
00:53:20.590 --> 00:53:22.270
get more luminous as they age a little bit,

1398
00:53:22.270 --> 00:53:24.870
and it's a slow process. But with the sun,

1399
00:53:25.190 --> 00:53:27.590
we think the sun was 30 dimmer

1400
00:53:28.150 --> 00:53:31.150
when it was born to how it is now. So

1401
00:53:31.150 --> 00:53:33.350
that means the Earth at the time got 30% less

1402
00:53:33.350 --> 00:53:35.950
energy, which would have put it, with its

1403
00:53:35.950 --> 00:53:38.950
current atmosphere, too cold to support

1404
00:53:38.950 --> 00:53:41.910
life. Um, that was offset by the

1405
00:53:41.910 --> 00:53:43.510
fact we had a very different atmosphere than

1406
00:53:43.510 --> 00:53:46.220
in a significant greenhouse effect,

1407
00:53:46.540 --> 00:53:48.620
which was lessened due to the influence of

1408
00:53:48.620 --> 00:53:51.180
life stripping out carbon dioxide,

1409
00:53:51.180 --> 00:53:53.020
particularly from the atmosphere, and keeping

1410
00:53:53.020 --> 00:53:55.620
us mostly there and thereabouts. But what

1411
00:53:55.620 --> 00:53:57.740
that means is that if we find a planet now

1412
00:53:58.380 --> 00:54:00.180
and that planet is near the outer edge of the

1413
00:54:00.180 --> 00:54:02.220
habitable zone, um, everybody will go, well,

1414
00:54:02.220 --> 00:54:03.820
it's in the habitable zone. That's great.

1415
00:54:04.300 --> 00:54:06.460
Whereas my question would then be, but how

1416
00:54:06.460 --> 00:54:08.060
long has it been in the habitable zone?

1417
00:54:08.460 --> 00:54:10.960
Because when the SAR was younger, it was a

1418
00:54:10.960 --> 00:54:13.000
little bit dimmer. The habitable zone would

1419
00:54:13.000 --> 00:54:14.400
have been closer in, and that planet might

1420
00:54:14.400 --> 00:54:16.520
well have been outside it. So I don't

1421
00:54:16.520 --> 00:54:18.320
necessarily think that that 1 billion year

1422
00:54:18.320 --> 00:54:20.880
clock would start until the planet was in the

1423
00:54:20.880 --> 00:54:22.440
habitable zone. So we'll probably then be

1424
00:54:22.440 --> 00:54:25.080
able to rule some planets out on the

1425
00:54:25.080 --> 00:54:28.080
basis of the fact that they could be

1426
00:54:28.080 --> 00:54:29.520
in the habitable zone, uh, now, but they

1427
00:54:29.520 --> 00:54:32.040
haven't been full long enough. Yeah, the star

1428
00:54:32.040 --> 00:54:34.120
has all these effects. Never mind the fact

1429
00:54:34.120 --> 00:54:36.560
that astronomers often joke that three out of

1430
00:54:36.560 --> 00:54:38.240
every two stars are in a multiple star

1431
00:54:38.240 --> 00:54:41.050
system. Them multiple, um, stars are

1432
00:54:41.050 --> 00:54:43.690
very, very common. And uh, that adds a whole

1433
00:54:43.690 --> 00:54:46.610
extra level of complexity, Both to

1434
00:54:46.610 --> 00:54:48.490
the understanding of the lives of the planets

1435
00:54:48.490 --> 00:54:50.970
in those stars, but also in our ability to

1436
00:54:50.970 --> 00:54:52.850
study them. Because you've got more than one

1437
00:54:52.850 --> 00:54:54.930
stars like to factor rain all close together.

1438
00:54:55.410 --> 00:54:57.890
It's much nastier and much more complicated.

1439
00:54:58.530 --> 00:55:00.090
So there's a lot of ways that the stars can

1440
00:55:00.090 --> 00:55:01.950
factor in. And I think that's only a, ah,

1441
00:55:02.010 --> 00:55:04.930
very, very broad brushstrokes view, but

1442
00:55:04.930 --> 00:55:07.600
you can see how. So what I'm thinking is you

1443
00:55:07.600 --> 00:55:10.480
can bring in all these different ideas and

1444
00:55:10.480 --> 00:55:13.120
halve them as a slider. This kind of star

1445
00:55:13.120 --> 00:55:14.800
could have planets around it with life, but

1446
00:55:14.800 --> 00:55:17.680
it's not as good a target as this one. Now,

1447
00:55:17.680 --> 00:55:19.160
everybody could build their own algorithm out

1448
00:55:19.160 --> 00:55:20.480
of this, But I'd like to think that when

1449
00:55:20.480 --> 00:55:22.600
we're trying to pick the target, you take

1450
00:55:22.600 --> 00:55:25.120
into account the star that it's going around,

1451
00:55:25.120 --> 00:55:28.000
how active it is. Is it a single star, Is

1452
00:55:28.000 --> 00:55:30.600
it old enough, all these kind of factors

1453
00:55:31.240 --> 00:55:33.450
and Then you can start looking at the

1454
00:55:33.450 --> 00:55:35.530
planetary system that it's in. And there's a

1455
00:55:35.530 --> 00:55:37.010
lot to talk about there, I think.

1456
00:55:37.410 --> 00:55:40.330
Andrew Dunkley: Yes, absolutely. Uh, and in

1457
00:55:40.330 --> 00:55:42.930
our next, um, ah, special,

1458
00:55:43.460 --> 00:55:46.290
um, between Q and A episodes, we will,

1459
00:55:46.360 --> 00:55:49.249
um, look more into, um, the, the

1460
00:55:49.250 --> 00:55:50.370
planet side of things.

1461
00:55:50.530 --> 00:55:53.490
I, I guess just to conclude, um, I'll throw

1462
00:55:53.570 --> 00:55:56.490
one at you. Um, and, and this answer is

1463
00:55:56.490 --> 00:55:58.130
always different, depending on who you ask.

1464
00:55:58.130 --> 00:56:00.830
But, uh, we. What do you think the odds are

1465
00:56:00.830 --> 00:56:03.510
that we will find some form of life?

1466
00:56:05.510 --> 00:56:08.350
Jonti Horner: I'm an optimist. I think the answer to

1467
00:56:08.350 --> 00:56:10.510
it will be yes, we will find some sort of

1468
00:56:10.510 --> 00:56:12.630
life. I think the harder question is when?

1469
00:56:13.670 --> 00:56:16.630
Now, if we find life in

1470
00:56:16.630 --> 00:56:18.230
a million years time when we're not even

1471
00:56:18.230 --> 00:56:19.670
human anymore, but we've hung around, we've

1472
00:56:19.670 --> 00:56:22.190
managed to survive. That's not very edifying

1473
00:56:22.190 --> 00:56:23.550
for me and you because it's long time to

1474
00:56:23.550 --> 00:56:25.790
work. But as I said earlier on, I don't think

1475
00:56:25.790 --> 00:56:27.400
it's a question of if, it's a question of, of

1476
00:56:27.400 --> 00:56:30.080
when. Because I find it vanishingly

1477
00:56:30.400 --> 00:56:32.640
improbable for us to be the only

1478
00:56:33.360 --> 00:56:36.240
system with life. And it's a numbers game for

1479
00:56:36.240 --> 00:56:38.040
me. You know, we've got a galaxy with between

1480
00:56:38.040 --> 00:56:40.560
200 and 400,000 million

1481
00:56:40.560 --> 00:56:43.440
stars. There are more galaxies in the

1482
00:56:43.440 --> 00:56:46.160
visible universe, certainly than there are

1483
00:56:46.640 --> 00:56:49.200
planets in our galaxy, probably more than

1484
00:56:49.200 --> 00:56:51.560
there are grains of sand in our galaxy. All

1485
00:56:51.560 --> 00:56:53.000
of them with hundreds of thousands of

1486
00:56:53.000 --> 00:56:55.970
millions of stars to say that

1487
00:56:55.970 --> 00:56:58.370
out of. If you run the numbers, you get

1488
00:56:58.370 --> 00:57:00.610
sextillions, septillions, even

1489
00:57:00.610 --> 00:57:03.610
octillions bonkersly full

1490
00:57:03.610 --> 00:57:06.490
on numbers of planets out there that

1491
00:57:06.490 --> 00:57:09.490
were the only place that got life. That tells

1492
00:57:09.490 --> 00:57:11.290
you that life is effectively impossible and

1493
00:57:11.290 --> 00:57:14.250
we're a fluke. Now, that

1494
00:57:14.810 --> 00:57:16.610
could be the case. If that's the case, what

1495
00:57:16.610 --> 00:57:18.210
we've got here on Earth becomes even more

1496
00:57:18.210 --> 00:57:20.570
precious. And there is an even greater

1497
00:57:20.570 --> 00:57:23.420
incentive for us to keep an eye on what

1498
00:57:23.420 --> 00:57:25.860
we're doing so that Earth is still capable of

1499
00:57:25.860 --> 00:57:28.220
hurting life in the future. But I think in

1500
00:57:28.220 --> 00:57:30.540
reality, life will actually be more common

1501
00:57:30.540 --> 00:57:32.220
than that. And you don't need to be much more

1502
00:57:32.220 --> 00:57:34.980
common than that for life to be abundant in

1503
00:57:34.980 --> 00:57:37.940
the galaxy. Let's imagine that life is

1504
00:57:37.940 --> 00:57:40.580
found on one planet in one

1505
00:57:40.740 --> 00:57:43.020
billion. That's billion with a B. So one in a

1506
00:57:43.020 --> 00:57:45.820
thousand million. Now we're finding that on

1507
00:57:45.820 --> 00:57:47.780
average, all stars have planets, probably

1508
00:57:47.780 --> 00:57:49.780
have a number of planets. So if we say

1509
00:57:49.780 --> 00:57:51.580
roughly there are 10 planets per star, there

1510
00:57:51.580 --> 00:57:54.230
will be 4,4 trillion planets in our galaxy.

1511
00:57:54.710 --> 00:57:57.710
If one in a billion had life on

1512
00:57:57.710 --> 00:58:00.190
it, that will mean there were 4,000 inhabited

1513
00:58:00.190 --> 00:58:03.110
planets in our galaxy. Not a

1514
00:58:03.110 --> 00:58:04.910
big number. The nearest one will be so far

1515
00:58:04.910 --> 00:58:06.510
away. In that case we wouldn't find life for

1516
00:58:06.510 --> 00:58:09.430
a long time. But life could be common

1517
00:58:09.670 --> 00:58:11.710
and we still wouldn't find it. The more you

1518
00:58:11.710 --> 00:58:14.610
increase that likelihood of life, the nearer

1519
00:58:14.610 --> 00:58:16.790
uh, the nearest examples will be in, the

1520
00:58:16.790 --> 00:58:18.150
sooner we'll find it. And that's why I think

1521
00:58:18.150 --> 00:58:20.700
proximity will tell us a lot about the

1522
00:58:20.700 --> 00:58:23.220
probability of life and that

1523
00:58:23.380 --> 00:58:26.380
if we find life, the next step is to

1524
00:58:26.380 --> 00:58:28.340
figure out we are not alone, we know we're

1525
00:58:28.340 --> 00:58:31.140
not alone, how common is life. Now the other

1526
00:58:31.140 --> 00:58:33.100
thing I think factors into it, I think is a

1527
00:58:33.100 --> 00:58:35.740
lovely kind of sci fi thing to discuss all

1528
00:58:35.740 --> 00:58:36.980
the way through. You mentioned early on

1529
00:58:36.980 --> 00:58:39.220
carbon based life and technologically

1530
00:58:39.220 --> 00:58:42.100
advanced life and we drifted away. The

1531
00:58:42.100 --> 00:58:45.060
one place where I think that life that is

1532
00:58:45.060 --> 00:58:46.740
different to us is something we could

1533
00:58:46.740 --> 00:58:49.290
possibly find is silicon based life.

1534
00:58:50.170 --> 00:58:53.170
Now the reason for that is not from

1535
00:58:53.170 --> 00:58:56.050
the point of view of um, silicon

1536
00:58:56.050 --> 00:58:59.050
people who have evolved in the way we have

1537
00:58:59.050 --> 00:59:01.330
done. I'm thinking more kind of second

1538
00:59:01.330 --> 00:59:03.970
generation life. Now our exploration of the

1539
00:59:03.970 --> 00:59:06.690
solar system is done by our robot envoys and

1540
00:59:06.690 --> 00:59:08.690
we're sending them near enough to harm that

1541
00:59:08.690 --> 00:59:11.370
we can tell them what to do. But we are

1542
00:59:11.370 --> 00:59:14.050
developing to certain controversy at the

1543
00:59:14.050 --> 00:59:15.810
current time. We're developing a greater and

1544
00:59:15.810 --> 00:59:17.710
greater ability to visualise, develop things

1545
00:59:17.710 --> 00:59:19.110
that can make decisions for themselves

1546
00:59:19.110 --> 00:59:21.830
without human input, things like AI and other

1547
00:59:21.830 --> 00:59:24.350
systems. And if we get to the point where we

1548
00:59:24.350 --> 00:59:26.830
want to explore around other

1549
00:59:26.830 --> 00:59:29.790
stars, we'll need to develop spacecraft that

1550
00:59:29.790 --> 00:59:31.310
have enough autonomy to make their own

1551
00:59:31.310 --> 00:59:34.070
decisions. You go back to the idea and I

1552
00:59:34.070 --> 00:59:35.190
don't know what's happened to it in recent

1553
00:59:35.190 --> 00:59:36.870
years, but the idea of Project Starshot,

1554
00:59:36.870 --> 00:59:38.790
where they made a little spacecraft, shot

1555
00:59:38.790 --> 00:59:40.470
them off with laser, then they got to proxima

1556
00:59:40.470 --> 00:59:43.310
Centauri in 25 years, travelling at a fifth

1557
00:59:43.310 --> 00:59:45.550
of the speed of light. You do that,

1558
00:59:46.350 --> 00:59:48.270
they get to Proxima Centauri. If they've got

1559
00:59:48.270 --> 00:59:49.990
to ask us what to do, they send a signal to

1560
00:59:49.990 --> 00:59:52.270
us. Takes four and a bit years to get here,

1561
00:59:52.510 --> 00:59:54.190
takes five years to get back, and by the time

1562
00:59:54.190 --> 00:59:55.830
it reaches them, they're a light year beyond

1563
00:59:55.830 --> 00:59:57.870
the system and it's like, well too late. So

1564
00:59:57.870 --> 00:59:59.190
we have to give them a certain level of

1565
00:59:59.190 --> 01:00:01.310
autonomy. And the more complex their mission

1566
01:00:01.310 --> 01:00:03.030
is going to be, the more autonomous it have

1567
01:00:03.030 --> 01:00:05.790
to be. Which leads to uh, the very science

1568
01:00:05.790 --> 01:00:08.750
fiction idea that when we move out beyond the

1569
01:00:08.750 --> 01:00:10.670
solar system, if we move out beyond the solar

1570
01:00:10.670 --> 01:00:13.080
system, we will be preceded by

1571
01:00:13.400 --> 01:00:15.640
a wave of life that is not us,

1572
01:00:16.200 --> 01:00:18.720
that is our life that has a

1573
01:00:18.720 --> 01:00:21.440
creator. That creator is humanity. That is

1574
01:00:21.440 --> 01:00:23.640
silicon based life that we send out, whether

1575
01:00:23.640 --> 01:00:25.640
they're von Neumann machines, whether they

1576
01:00:25.640 --> 01:00:28.200
are incredibly advanced AI machines without

1577
01:00:28.200 --> 01:00:31.000
the capacity to reproduce themselves. We

1578
01:00:31.000 --> 01:00:33.800
will send out artificially

1579
01:00:34.440 --> 01:00:37.440
built silicon life forms. And again,

1580
01:00:37.440 --> 01:00:40.050
that's a lovely, fairly lost X

1581
01:00:40.210 --> 01:00:42.370
sci fi series called the Bobby Verse,

1582
01:00:42.810 --> 01:00:45.370
um, which follows that kind of idea in terms

1583
01:00:45.370 --> 01:00:48.370
of future Earth. Well, guy

1584
01:00:48.370 --> 01:00:50.730
in the current day dies, but has invested in

1585
01:00:50.730 --> 01:00:53.290
cryogenics and his head is frozen and he

1586
01:00:53.290 --> 01:00:55.810
wakes up and he's essentially put into a Van

1587
01:00:55.810 --> 01:00:57.810
Neumann machine and shot out into the stars.

1588
01:00:58.210 --> 01:00:59.850
And that, that's a really interesting one

1589
01:00:59.850 --> 01:01:01.690
because it's silicon based life that is also

1590
01:01:01.690 --> 01:01:03.570
human. Let me figure that one out. But it's

1591
01:01:03.570 --> 01:01:06.370
good fun following again that very

1592
01:01:06.370 --> 01:01:08.800
dangerous assumption that other life would

1593
01:01:08.800 --> 01:01:10.600
follow the same path where we follow. And it

1594
01:01:10.600 --> 01:01:12.400
seems like we are going down this AI and

1595
01:01:12.400 --> 01:01:15.320
increasing complexity and increasing autonomy

1596
01:01:15.320 --> 01:01:18.280
route. You'd then argue that other species

1597
01:01:18.280 --> 01:01:20.480
sending out craft into the galaxy

1598
01:01:20.960 --> 01:01:23.040
would send out autonomous

1599
01:01:23.120 --> 01:01:25.520
intelligent silicon machines

1600
01:01:26.000 --> 01:01:28.640
before they send themselves out. And

1601
01:01:28.640 --> 01:01:30.360
therefore, you know, I think we're more

1602
01:01:30.360 --> 01:01:32.400
likely, if we're ever to bump into aliens, to

1603
01:01:32.400 --> 01:01:34.200
run into one of these probes or one of these

1604
01:01:34.200 --> 01:01:36.680
machines rather than the aliens themselves. I

1605
01:01:36.680 --> 01:01:38.240
think there is a very real chance that if we

1606
01:01:38.240 --> 01:01:41.120
find intelligent advanced life, it could be

1607
01:01:41.120 --> 01:01:43.440
silicon based rather than carbon based. But

1608
01:01:43.440 --> 01:01:45.600
it's silicon based life that was created by

1609
01:01:45.600 --> 01:01:48.440
carbon based life, which I mean,

1610
01:01:48.440 --> 01:01:50.080
leads to really interesting questions about

1611
01:01:50.080 --> 01:01:52.200
philosophy and religion and all those kind of

1612
01:01:52.200 --> 01:01:54.520
things which are not my forte. But you know,

1613
01:01:54.520 --> 01:01:56.560
it does ask interesting questions about

1614
01:01:56.560 --> 01:01:58.960
origin and creation when you think about it

1615
01:01:58.960 --> 01:02:00.600
from the context of that, which is one of the

1616
01:02:00.600 --> 01:02:02.370
things that driven, like I said, a lot of

1617
01:02:02.370 --> 01:02:04.410
wonderful and wonderfully entertaining sci fi

1618
01:02:04.410 --> 01:02:05.010
over the years.

1619
01:02:05.490 --> 01:02:08.490
Andrew Dunkley: Yeah, yeah, as you said earlier, we could, we

1620
01:02:08.490 --> 01:02:10.850
could talk about this for a week, but we

1621
01:02:10.850 --> 01:02:13.610
can't. Um, but uh, I

1622
01:02:13.610 --> 01:02:16.250
do uh, want to direct people to your paper if

1623
01:02:16.250 --> 01:02:18.690
uh, people are interested in reading your

1624
01:02:18.690 --> 01:02:21.650
paper from 2010. Uh, it's

1625
01:02:21.750 --> 01:02:24.690
uh, called Determining Habitability. Which

1626
01:02:24.770 --> 01:02:27.380
exo Earths, uh, should we search for for

1627
01:02:27.380 --> 01:02:30.100
life? And you can find it on the ARXIV

1628
01:02:30.180 --> 01:02:31.780
website, is that right, John?

1629
01:02:31.860 --> 01:02:33.340
Jonti Horner: Yeah. So that was published in the

1630
01:02:33.340 --> 01:02:35.100
International Journal of Astrobiology in

1631
01:02:35.100 --> 01:02:36.620
2010. So the ones who want the kind of

1632
01:02:36.620 --> 01:02:38.020
scientific reference, it's International

1633
01:02:38.100 --> 01:02:41.100
Journal of Astrobiology, Volume 9, page

1634
01:02:41.100 --> 01:02:44.100
273 onwards. But um, if

1635
01:02:44.100 --> 01:02:46.060
you find it on NASA rads, it'll give you the

1636
01:02:46.060 --> 01:02:48.420
archive link which is the pre print Version,

1637
01:02:48.580 --> 01:02:51.540
which basically means it's in my formatting

1638
01:02:51.540 --> 01:02:53.620
rather than journal formatting. And this is,

1639
01:02:54.450 --> 01:02:56.450
it's actually a, uh, handy aside that I'm

1640
01:02:56.450 --> 01:02:58.130
sure, as we mentioned before, the

1641
01:02:59.170 --> 01:03:01.570
way that a lot of science

1642
01:03:01.810 --> 01:03:04.290
works has led to the creation of the most

1643
01:03:04.290 --> 01:03:06.610
profitable, um, um, and

1644
01:03:06.690 --> 01:03:09.210
problematic, um, companies in the world,

1645
01:03:09.210 --> 01:03:11.450
which are the publishing companies. And so

1646
01:03:11.450 --> 01:03:13.130
the way a scientist works is we do all this

1647
01:03:13.130 --> 01:03:15.410
work, da da da da da. Hooray, hooray, hooray.

1648
01:03:15.410 --> 01:03:17.090
We then write a paper to tell the world about

1649
01:03:17.090 --> 01:03:19.490
it. We send that off to a journal who

1650
01:03:19.910 --> 01:03:21.550
gets another scientist to volunteer their

1651
01:03:21.550 --> 01:03:23.830
time, unpaid for free, to referee it.

1652
01:03:24.870 --> 01:03:27.070
Then they're charged, typically the scientist

1653
01:03:27.070 --> 01:03:28.830
who's written that paper money to publish

1654
01:03:28.830 --> 01:03:31.310
that paper for them and then charge everybody

1655
01:03:31.310 --> 01:03:33.550
for the privilege of reading it. So if I want

1656
01:03:33.550 --> 01:03:35.509
the journal, if I want to read the journal

1657
01:03:35.509 --> 01:03:37.750
versions of my papers. Fortunately,

1658
01:03:37.750 --> 01:03:39.830
universities have paid access to a lot of

1659
01:03:39.830 --> 01:03:41.470
journals, but I'm fundamentally paying to

1660
01:03:41.470 --> 01:03:44.070
read my own work. And this is

1661
01:03:45.030 --> 01:03:47.670
not ideal. Big deal. I think partly because

1662
01:03:47.670 --> 01:03:48.950
as a scientist, you know, I'm paid by

1663
01:03:48.950 --> 01:03:51.550
taxpayers money, people are paying me to do

1664
01:03:51.550 --> 01:03:54.270
this work. To me, it is really important that

1665
01:03:54.270 --> 01:03:55.910
they know what we're doing, they know what

1666
01:03:55.910 --> 01:03:57.590
they're getting for their money. And, um,

1667
01:03:57.590 --> 01:03:59.150
part of that is be a science communicator.

1668
01:03:59.150 --> 01:04:00.950
And I encourage any scientists or budding

1669
01:04:00.950 --> 01:04:03.190
scientists, don't refocus on the science.

1670
01:04:03.190 --> 01:04:04.830
Focus on communication as well, because if

1671
01:04:04.830 --> 01:04:06.510
you do science but can't communicate it, no

1672
01:04:06.510 --> 01:04:09.510
one will know what you've done. But to get

1673
01:04:09.510 --> 01:04:12.450
around that, what we do in astronomy and

1674
01:04:12.450 --> 01:04:14.570
what many disciplines do, is that, uh, we put

1675
01:04:14.570 --> 01:04:17.050
preprints up on a publicly

1676
01:04:17.050 --> 01:04:19.970
accessible free place. And it's in astronomy,

1677
01:04:19.970 --> 01:04:21.970
it's just accepted that with very rare

1678
01:04:21.970 --> 01:04:24.450
exceptions, journals will let you do this. So

1679
01:04:24.450 --> 01:04:26.130
when we get our paper and we've written it,

1680
01:04:27.170 --> 01:04:29.370
some disciplines in astronomy will put the

1681
01:04:29.370 --> 01:04:31.330
paper up on the archive when it's submitted.

1682
01:04:31.970 --> 01:04:33.810
Some will wait until it's accepted by the

1683
01:04:33.810 --> 01:04:35.370
journal when it's refereed. I've always

1684
01:04:35.370 --> 01:04:37.410
waited till acceptance, but occasionally if

1685
01:04:37.410 --> 01:04:38.970
you've made a big discovery, you want to stop

1686
01:04:38.970 --> 01:04:40.910
somebody scooping you to you, you put it up

1687
01:04:40.910 --> 01:04:42.910
at submission. There's a growing effort by

1688
01:04:42.910 --> 01:04:44.430
scientists to put it up at submission, to

1689
01:04:44.430 --> 01:04:46.230
actively solicit feedback from the community

1690
01:04:46.230 --> 01:04:48.950
to improve the work, which is good. But those

1691
01:04:48.950 --> 01:04:50.882
papers go upon arXiv.

1692
01:04:51.098 --> 01:04:53.910
ArXiv, yeah. Um, be very

1693
01:04:53.910 --> 01:04:56.830
careful. There is another platform out

1694
01:04:56.830 --> 01:04:59.230
there where the letters in ARXIV are shifted

1695
01:04:59.230 --> 01:05:01.830
around, which is where a community of people

1696
01:05:01.830 --> 01:05:04.670
who espouse Ideas that are not scientifically

1697
01:05:04.670 --> 01:05:07.210
verifiable will put their work, uh, and

1698
01:05:07.210 --> 01:05:08.650
publish their own little papers. It's a

1699
01:05:08.650 --> 01:05:10.970
different thing. But ARXIV is a

1700
01:05:10.970 --> 01:05:13.770
repository of free to view things. So if

1701
01:05:13.770 --> 01:05:16.570
you are searching for papers, NASA's ADS

1702
01:05:16.570 --> 01:05:18.770
system is wonderful. When you click on a

1703
01:05:18.770 --> 01:05:21.210
given paper in there, most of them, but not

1704
01:05:21.210 --> 01:05:22.850
all of them will have a line that says

1705
01:05:22.850 --> 01:05:25.090
journal version or ADS version. But there'll

1706
01:05:25.090 --> 01:05:27.370
also be a line that says preprint. And if you

1707
01:05:27.370 --> 01:05:28.890
click on the preprint links, it will take you

1708
01:05:28.890 --> 01:05:31.090
to the archive and allow you to read the

1709
01:05:31.090 --> 01:05:33.620
paper for free. Just to be aware that that is

1710
01:05:33.620 --> 01:05:36.340
a version some of the time before

1711
01:05:36.340 --> 01:05:37.820
refereeing, most of the time after

1712
01:05:37.820 --> 01:05:39.980
refereeing, but before publishing in edits

1713
01:05:40.220 --> 01:05:42.420
effectively. So the link you've got to that

1714
01:05:42.420 --> 01:05:45.220
is the pre print version of that paper. The

1715
01:05:45.220 --> 01:05:47.180
other caution I give to people is that uh, it

1716
01:05:47.180 --> 01:05:49.700
is 16 years old. So all of the areas I talk

1717
01:05:49.700 --> 01:05:51.660
about in it have moved on. We've learned

1718
01:05:51.660 --> 01:05:53.860
more, um, we can talk a bit more about it

1719
01:05:53.860 --> 01:05:56.260
next time as well. But always when you read

1720
01:05:56.260 --> 01:05:58.130
things, be conscious of the fact that that

1721
01:05:58.290 --> 01:06:00.570
science, uh, is fluid. Science changes, our

1722
01:06:00.570 --> 01:06:02.770
knowledge changes. I see just in the news

1723
01:06:02.770 --> 01:06:05.570
recently, Jason Isaacs Isaacson,

1724
01:06:05.570 --> 01:06:07.810
who's I think the head guy at Nashville at

1725
01:06:07.810 --> 01:06:10.410
the minute, who's a wealthy multi billionaire

1726
01:06:10.410 --> 01:06:13.210
type guy, um, is arguing that the US is

1727
01:06:13.210 --> 01:06:15.450
wanting to strongly build a scientific case

1728
01:06:15.450 --> 01:06:17.210
why Pluto should be restored as a planet

1729
01:06:17.210 --> 01:06:19.770
because fundamentally we discovered it, so it

1730
01:06:19.770 --> 01:06:21.450
should still be a planet. And Clyde Tomball

1731
01:06:21.450 --> 01:06:22.610
would be turning in his grave.

1732
01:06:24.780 --> 01:06:27.780
That is what it is. But it's, it is

1733
01:06:27.780 --> 01:06:30.740
important to keep in mind that science

1734
01:06:30.740 --> 01:06:33.340
is fluid, it moves. Whereas once something is

1735
01:06:33.340 --> 01:06:35.820
published that's static, you know, it's a

1736
01:06:35.820 --> 01:06:38.500
window on our knowledge at a time rather than

1737
01:06:38.500 --> 01:06:41.500
necessarily the modern version. If I were

1738
01:06:41.500 --> 01:06:43.460
to rewrite that paper now, there'd be

1739
01:06:43.460 --> 01:06:46.340
advances of course, absolutely.

1740
01:06:46.340 --> 01:06:49.260
Andrew Dunkley: But um, yes, um, I think we're trying to

1741
01:06:49.260 --> 01:06:51.100
arrange to put the link on the show notes.

1742
01:06:51.100 --> 01:06:53.550
I'll just have to remind Huw you about that.

1743
01:06:53.790 --> 01:06:55.910
We might wrap it up there. Jonty. Fascinating

1744
01:06:55.910 --> 01:06:58.310
topic and uh, it's one we get a heck of a lot

1745
01:06:58.310 --> 01:07:01.030
of questions about. So, um, yeah, hopefully

1746
01:07:01.030 --> 01:07:03.070
there's a, uh, bit of information in there to

1747
01:07:03.550 --> 01:07:05.790
keep people's minds whirring.

1748
01:07:06.190 --> 01:07:08.510
Johnty, thanks very much. We will, uh, see

1749
01:07:08.510 --> 01:07:09.470
you again real soon.

1750
01:07:09.470 --> 01:07:10.910
Jonti Horner: It's an absolute pleasure. Thank you for

1751
01:07:10.910 --> 01:07:11.310
having me.

1752
01:07:11.870 --> 01:07:13.590
Andrew Dunkley: Professor John Dee Horner, professor of

1753
01:07:13.590 --> 01:07:15.670
Astrophysics at the University of Southern

1754
01:07:15.670 --> 01:07:17.630
Queensland, standing in for Fred Watson

1755
01:07:17.630 --> 01:07:20.260
Watson. And thanks to Huey in the studio. Uh,

1756
01:07:20.260 --> 01:07:23.200
Huw couldn't be with us today. Um, he got,

1757
01:07:23.200 --> 01:07:24.220
uh, a bit confused.

1758
01:07:24.220 --> 01:07:24.500
Jonti Horner: We.

1759
01:07:24.500 --> 01:07:26.740
Andrew Dunkley: We know of one planet where there is life.

1760
01:07:27.380 --> 01:07:29.580
Huw thought we meant that he was the only

1761
01:07:29.580 --> 01:07:32.140
life form on the planet, so he didn't see any

1762
01:07:32.140 --> 01:07:34.620
need to turn up today. And from me, Andrew

1763
01:07:34.620 --> 01:07:36.340
Dunkley, thanks for your company. We'll see

1764
01:07:36.340 --> 01:07:38.180
you on the next episode of Space Nuts.

1765
01:07:38.180 --> 01:07:41.180
Jonti Horner: Bye. Bye. You've been listening to

1766
01:07:41.180 --> 01:07:42.740
the Space Nuts podcast,

1767
01:07:44.340 --> 01:07:47.100
available at Apple Podcasts, Spotify,

1768
01:07:47.340 --> 01:07:50.060
iHeartRadio or your favourite podcast

1769
01:07:50.060 --> 01:07:51.820
player. You can also stream on

1770
01:07:51.820 --> 01:07:53.500
demand@bytes.com.

1771
01:07:53.820 --> 01:07:55.860
Andrew Dunkley: this has been another quality podcast

1772
01:07:55.860 --> 01:07:57.980
production from bytes.um.com.