Astrobiology Adventures: Exploring Life Beyond Earth | Space Nuts: Astronomy Insights & Cosmic...

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Hi there. Thanks for joining us again.


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This is Space Nuts, where we talk


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astronomy and space science. And my name


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is Andrew Dunley, your host. Great to


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have your company. Now, normally I'd be


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joined by Professor Fred Watson, but he


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is away visiting family at the moment.


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And because he was going to be away and


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then I'm going to be away and we tried


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to cram episodes in and uh we just we


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couldn't do enough in the amount of time


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we had, uh we invited Professor Jotty


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Horner to join us and uh we're going to


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do some specials. You might have heard


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the last one, uh which was very engaging


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and interesting and fascinating and


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long. Uh this time we we're going down a


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different road. We're going to focus the


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whole program on astro biology. Strap


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in. We'll do that right now.


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>> 15 seconds. Guidance is internal. 10 9


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Ignition sequence start.


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>> Space nuts.


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>> 5 4 3 2


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>> 1 2 3 4 5 5 4 3 2 1


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>> Space nuts.


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>> Astronauts report. It feels good.


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>> And here he is again. Professor of


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astrophysics at the University of


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Southern Queensland, Johnny her. Good


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day, Johnny.


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>> Good day. How are you going?


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>> I'm well. Good to see you again. And uh


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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 archive website.


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Uh it's um


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>> ancient.


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


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since you wrote that. But one of the


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interesting parts was uh look, it's been


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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


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before we start finding Earthlike


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planets. And that's really going to make


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the search for life beyond our solar


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system really really interesting. So


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those 16 years have passed. Have we got


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the Have we got the equipment yet? I


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suspect we have. It depends where you're


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looking, I think. I mean, in terms of


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looking at the planets around other


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stars, we can now learn a lot more about


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them than we could 16 years ago when I


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wrote the paper. that particular paper,


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


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a perpetual thing. No matter how hard


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you work, there's always more to do. The


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other thing that goes along with it,


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which I think is worth saying right up


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at the very start, is that searching for


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life elsewhere is going to be one of the


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hardest things we've ever done. And


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absence of evidence is not necessarily


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evidence of absence. What I mean by that


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is we could in a remarkable turn of


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events in the next few months find life


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elsewhere. you know, that's kind of the


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ultimate extreme soonest possible. Um,


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very unlikely to happen. Alternatively,


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we might still be looking in a century.


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If we're still looking in a century,


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that doesn't mean that there isn't any


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life 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


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elsewhere, that a it will be awesome


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because, hey, look, we found life


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elsewhere and we've answered the


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ultimate question. Are we alone?


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But the sooner we find life elsewhere,


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the other thing it's telling us is that


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life must be fairly common in the


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universe. The scarcer life is, the


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harder it will be to find and therefore


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the longer it will take us to find. And


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now the ultimate extreme of that is that


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this is the only place that there is


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life. And it'll be very hard to conclude


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that even if we were talking through a


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time warp in 10,000 years when humanity


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is taking its fledgling steps into the


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galaxy or whatever, if we haven't found


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life by then, we'll be confident that


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life is very rare and very precious.


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>> That doesn't mean that there is not life


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somewhere else in the universe. And it's


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what are the challenges with this? I I


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would like to think that we'll find the


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answer to that question in our lifetime.


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But the only way we'll get an answer to


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the question, are we alone within our


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lifetime is if that answer is no. If


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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.


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You know, when I was a kid, when you


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were a kid, one of the big questions was


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is the solar system unique or are there


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planets around other stars? And we'll


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talk about that more in the next


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episode. But there is nobody under the


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age of 30 31 alive on this planet that


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grew up in that shared universe with you


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and I. So that fundamental question got


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answered and answered in abundance and


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answering that question is the first


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real step to say is there life elsewhere


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beyond the solar system


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>> because in order to find life beyond the


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solar system we first need to know that


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there's somewhere that life could exist.


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The question of life in the solar system


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is a different one and that's all part


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of astrobiology. So if you bundle all of


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this together, that question of are we


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alone? Is there life elsewhere? Which


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brings with it questions like what is


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the origin of life? Why are we here? How


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did life begin? How did it get


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established? What are the processes


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needed? Everything like that.


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>> Yeah.


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>> Is what gets bundled in in astrobiology.


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And astrobiology is a very very weird


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science. I know certainly early in my


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career a lot of older scientists viewed


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astrobiology in a similar way to the way


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a lot of astronomers view astrology


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almost. you know, they viewed it as


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being speculation, fiction, and hook,


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you know, total bogus, waste of time


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stuff,


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>> but it really isn't.


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>> Yeah. But one of the real challenges is


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uh it's not a question that one single


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discipline on its own can answer, right?


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It's not like in astronomy, you you're


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studying how stars form, so you talk to


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astronomers. In astrobiology, if we're


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looking at everything to do with life,


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astronomers like myself can't do it on


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their own. Biologists can't do it on


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their own. You need geoysicists, you


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need chemists, you need every area of


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human scientific endeavor to come


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together because as scientists, our


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knowledge is somewhat siloed. I think


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I've said in previous episodes, the


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further you go away from what your


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specialtity is, the more out of date and


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the more superficial your knowledge is.


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So I always view my knowledge as being


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almost like a Christmas tree shape. I've


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got a lot of knowledge about a very


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narrow area at the top and the further


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you go from that area, the less


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knowledge I have, but the broader my


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knowledge base gets. And I think every


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human's like that. And you can almost


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imagine that if you're trying to answer


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the question of what you need for life,


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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


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to 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


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that is needed that is outside your


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silo. And so that's where the


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interdicciplinary nature comes in. No


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one discipline can answer it their own.


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And that means astrobiology conferences


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tend to be mind-bogglingly bonkers and


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you get people from very different


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disciplines along. And you learn a lot


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that updates your knowledge from when


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you went to high school. You also learn


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a lot that isn't about the science but


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is about the scientists. And it's really


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interesting because we all think we're


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individuals. It's like that Montipython


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


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and there's a voice at the back that


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goes, "I'm not.


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>> I'm not."


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>> Yeah. It's a bit like that. We're we all


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think we're all individuals and we're


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very unique in the way we think and the


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way we present. But when you go to one


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of these conferences that's so


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multiddisciplinary,


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the different disciplines present in


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different ways to one another. But


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within the discipline, there are


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similarities, you know. So if you see


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the talks I give, I have beautiful


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pictures and bright text, white or


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yellow on them, limited text, usually a


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dark background. And that's really


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common for astronomers. You go to a talk


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by a kind of plate tectonics person and


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suddenly you've got this mish mash of


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colors on a totally different background


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where there's a bit more text but the


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color schemes are a bit to me kind of


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psychedelic and like something you'd see


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out of a 1970s cartoon you know


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>> because they're used to working with


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these geological maps that um have a


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very different color palette and


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sensibility I think. And then you get


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talks from the biologists where they've


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got the name of one bacterium and it


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fills half of the page because it's such


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a lengthy scientific name and they've


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got loads of text.


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>> And so you learn a lot about how what


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you study at university and what


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discipline you go into trains you to


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think and trains you to problem solve


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because it trains you in a lot of


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different ways. essentially programs


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people and you know I find that side of


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things really fascinating because it's a


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good way to learn to improve your


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communication skills and you also pick


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up all this abundance of wow I never


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knew that you know and that's what we


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need if we are to answer questions like


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how did life begin where did life come


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from are we alone


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>> yeah and that's really an interesting


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question because uh it could be life not


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as we know it like we you know we're


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assuming carbon based life forms but


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there could be life forms that have been


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created out of a completely different


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soup mix. Uh two things I want to get


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out of the way quickly. The Drake


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equation which uh was created to try and


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assess how much intelligent life that


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was able to communicate existed in the


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universe and the answer is still one.


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And the Fermy paradox which says you


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know um that statistically there's a


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high probability of extraterrestrial


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life. So where is everybody? And that's


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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? And I


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suppose my first question to you is uh


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you're talking about finding life


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outside the solar system. Aren't we


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likely to find it first within the solar


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system?


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>> So that's a really good question. I was


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going to talk about that a bit as well


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because I think there are two different


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places in a broad sense we're looking


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for life elsewhere. One is


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in the outer solar system or on Mars,


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you know, in our solar system on one of


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the planets or on the icy objects and


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the other is beyond the solar system.


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>> And those two things have very different


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characteristics.


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What I mean by that is that objects that


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are in our solar system are in our


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backyard. They're the only things in


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astronomy that we can get up close and


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personal with. So in the solar system,


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the search life elsewhere is being


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driven by robotic exploration in the


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main. Yes, there's a little bit of


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observation from Earth. We saw that with


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the phosphine story on Venus that I


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ranted about a little bit last week. Um


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and the wonderful caution shown by


00:10:19.839 --> 00:10:21.190
scientists that was not necessarily


00:10:21.200 --> 00:10:23.829
reflected in the coverage. Um but a lot


00:10:23.839 --> 00:10:27.110
of the search in the solar system is


00:10:27.120 --> 00:10:29.509
robotic in nature. We send spacecraft to


00:10:29.519 --> 00:10:31.110
places to study them up close and


00:10:31.120 --> 00:10:33.350
personal and we can't do that around


00:10:33.360 --> 00:10:35.030
other stars. Around other stars, it's


00:10:35.040 --> 00:10:37.430
very much a remote sensing type deal. So


00:10:37.440 --> 00:10:38.710
there are different ways of doing it.


00:10:38.720 --> 00:10:41.350
Now I think there is a realistic chance


00:10:41.360 --> 00:10:43.509
we'll find life elsewhere in the solar


00:10:43.519 --> 00:10:45.110
system. There's a lot of good reasons


00:10:45.120 --> 00:10:47.750
for that. Now, before I dive into that a


00:10:47.760 --> 00:10:49.110
little bit, I'll just take a step back


00:10:49.120 --> 00:10:50.310
and come back to that point you made


00:10:50.320 --> 00:10:52.069
about life like us and carbon based life


00:10:52.079 --> 00:10:54.069
versus other things because it's really


00:10:54.079 --> 00:10:55.990
important to make explicit what is


00:10:56.000 --> 00:10:59.030
normally an implicit bias when


00:10:59.040 --> 00:11:00.069
scientists are talking about


00:11:00.079 --> 00:11:01.590
astrobiology.


00:11:01.600 --> 00:11:03.110
Um, it's really made clear when you


00:11:03.120 --> 00:11:05.990
think about NASA and efforts on the moon


00:11:06.000 --> 00:11:08.069
where they have on on Mars, sorry, where


00:11:08.079 --> 00:11:09.910
they have aggressively said the strategy


00:11:09.920 --> 00:11:12.470
to look for life is to follow the water.


00:11:12.480 --> 00:11:13.350
M


00:11:13.360 --> 00:11:16.470
>> what they're doing there is making an


00:11:16.480 --> 00:11:17.990
implicit assumption that is an


00:11:18.000 --> 00:11:19.829
assumption that is not always written


00:11:19.839 --> 00:11:21.350
out and is clear but is at the back of


00:11:21.360 --> 00:11:24.949
it that life that we look for will be


00:11:24.959 --> 00:11:26.870
life like us and I mean life like earth


00:11:26.880 --> 00:11:29.509
life now we can imagine you see it on


00:11:29.519 --> 00:11:31.030
science fiction all the time you know


00:11:31.040 --> 00:11:32.870
life that is very other it might be


00:11:32.880 --> 00:11:34.870
molten metal monsters on a magma planet


00:11:34.880 --> 00:11:36.790
or it might be an intelligent hydrogen


00:11:36.800 --> 00:11:38.230
cloud that nevertheless wants to flirt


00:11:38.240 --> 00:11:41.509
with Captain Kirk it's very different


00:11:41.519 --> 00:11:43.910
kinds of life. But fundamentally, we


00:11:43.920 --> 00:11:46.550
only know of one type of life that does


00:11:46.560 --> 00:11:49.750
exist and that's life like earth life.


00:11:49.760 --> 00:11:52.949
And so when we look for life elsewhere,


00:11:52.959 --> 00:11:55.110
at least in what is the early stages


00:11:55.120 --> 00:11:57.269
still, it is really important to look


00:11:57.279 --> 00:11:59.110
for something that we know can exist and


00:11:59.120 --> 00:12:01.590
does exist rather than looking for


00:12:01.600 --> 00:12:03.269
things that we could speculate might


00:12:03.279 --> 00:12:05.110
exist. If you've got to focus your


00:12:05.120 --> 00:12:08.230
efforts with limited resources, it makes


00:12:08.240 --> 00:12:10.949
sense to follow the kind of welltrodden


00:12:10.959 --> 00:12:12.629
footsteps of what we know about life on


00:12:12.639 --> 00:12:14.629
Earth. And from an astronomer's point of


00:12:14.639 --> 00:12:16.949
view, life on Earth needs three things.


00:12:16.959 --> 00:12:18.870
You know, it needs liquid water, it


00:12:18.880 --> 00:12:20.470
needs a source of energy and a source of


00:12:20.480 --> 00:12:22.069
nutrients. And quite often those two are


00:12:22.079 --> 00:12:24.470
the same thing, but not always. And


00:12:24.480 --> 00:12:26.310
wherever we find those things on Earth,


00:12:26.320 --> 00:12:28.150
we find life in abundance. And once life


00:12:28.160 --> 00:12:29.590
gets there, it's really hard to get rid


00:12:29.600 --> 00:12:31.509
of. You know, anybody who's had ants


00:12:31.519 --> 00:12:33.509
getting into their kitchen or the mice


00:12:33.519 --> 00:12:35.509
plague that we talked about last week


00:12:35.519 --> 00:12:38.310
knows just how life once it gets


00:12:38.320 --> 00:12:41.590
established keeps going. And so it makes


00:12:41.600 --> 00:12:43.670
sense. And a lot of what I'll talk about


00:12:43.680 --> 00:12:45.430
for all the rest of the episode is kind


00:12:45.440 --> 00:12:47.509
of based on this assumption that we're


00:12:47.519 --> 00:12:49.990
looking at at least initially for life


00:12:50.000 --> 00:12:52.069
like us that has the same needs as us


00:12:52.079 --> 00:12:54.230
where the us is the broad the entire


00:12:54.240 --> 00:12:56.790
panel play of life on Earth rather than


00:12:56.800 --> 00:12:58.710
us as in me and the having this chat


00:12:58.720 --> 00:13:01.829
back and forward. What that leads to


00:13:01.839 --> 00:13:03.110
though is a lot of studies that have


00:13:03.120 --> 00:13:04.550
been done for the solar system are very


00:13:04.560 --> 00:13:07.430
waterdriven. And if you go back decades,


00:13:07.440 --> 00:13:09.990
you could go back to the late 1800s when


00:13:10.000 --> 00:13:11.829
people were obsessed with this idea that


00:13:11.839 --> 00:13:13.350
there was an advanced technological


00:13:13.360 --> 00:13:15.829
civilization on Mars that was running


00:13:15.839 --> 00:13:17.190
out of time because the planet was


00:13:17.200 --> 00:13:19.269
desolate and barren. And this was all


00:13:19.279 --> 00:13:21.190
motivated by the observations of the


00:13:21.200 --> 00:13:23.990
canali, the channels on Mars that don't


00:13:24.000 --> 00:13:26.150
exist, which were mistransated as


00:13:26.160 --> 00:13:27.990
canals. And canals on Earth are a very


00:13:28.000 --> 00:13:30.230
clear sign of human activity.


00:13:30.240 --> 00:13:32.870
>> Yeah. People at that time were so


00:13:32.880 --> 00:13:34.389
certain that we'd already found life


00:13:34.399 --> 00:13:37.190
that when there was a prize awarded um a


00:13:37.200 --> 00:13:39.590
prize laid out sorry and announced I


00:13:39.600 --> 00:13:41.750
think it was like in 1899 or something


00:13:41.760 --> 00:13:43.350
for the search for life for the first


00:13:43.360 --> 00:13:45.190
person to discover life elsewhere to


00:13:45.200 --> 00:13:47.269
find evidence of life elsewhere. That


00:13:47.279 --> 00:13:50.230
prize explicitly excluded Mars because


00:13:50.240 --> 00:13:51.910
it was felt that life on Mars was so


00:13:51.920 --> 00:13:53.269
well established that that was a


00:13:53.279 --> 00:13:55.110
no-brainer. You know, it was such a


00:13:55.120 --> 00:13:56.389
thing in popular culture that when the


00:13:56.399 --> 00:13:58.069
War of the Worlds broadcast happened in


00:13:58.079 --> 00:14:00.629
the 1930s, people thought it was live


00:14:00.639 --> 00:14:02.150
news coverage and panicked.


00:14:02.160 --> 00:14:02.949
>> Yes. You know,


00:14:02.959 --> 00:14:05.030
>> the night that panicked America.


00:14:05.040 --> 00:14:08.470
>> Yeah. And there's this whole heritage of


00:14:08.480 --> 00:14:11.750
our expectation of life being common and


00:14:11.760 --> 00:14:14.710
it being life like us requiring water.


00:14:14.720 --> 00:14:16.949
When we went to Mars, like in the 1960s


00:14:16.959 --> 00:14:19.750
with spacecraft, Mars was shown to be


00:14:19.760 --> 00:14:21.269
the desolate arid world we knew today.


00:14:21.279 --> 00:14:23.189
That put to an end the thoughts of an


00:14:23.199 --> 00:14:25.910
advanced civilization there. And from


00:14:25.920 --> 00:14:27.750
that time onwards there was a period


00:14:27.760 --> 00:14:29.829
where arguments in astrobiology fell


00:14:29.839 --> 00:14:31.189
very much out of favor, out of fashion.


00:14:31.199 --> 00:14:32.389
And it was kind of viewed much more


00:14:32.399 --> 00:14:34.310
likely that life was almost unique. We


00:14:34.320 --> 00:14:36.470
were alone. There was no way you could


00:14:36.480 --> 00:14:38.310
look. And there's this argument that I


00:14:38.320 --> 00:14:41.910
often hear as that water is scarce in


00:14:41.920 --> 00:14:44.230
the universe. And that makes my head


00:14:44.240 --> 00:14:45.910
hurt. I think this is one of those big


00:14:45.920 --> 00:14:49.189
myths that is a myth of miscommunication


00:14:49.199 --> 00:14:51.590
or a myth of


00:14:51.600 --> 00:14:55.110
language being a personal thing. What I


00:14:55.120 --> 00:14:57.590
mean by that is and I I'm always try to


00:14:57.600 --> 00:14:59.509
be very aware of this when I'm as a


00:14:59.519 --> 00:15:02.790
communicator that words have different


00:15:02.800 --> 00:15:05.350
meanings to different people. And so the


00:15:05.360 --> 00:15:07.990
same word that I say you'll hear and it


00:15:08.000 --> 00:15:09.269
doesn't always mean the same thing to


00:15:09.279 --> 00:15:10.949
you or me. One of one of the best


00:15:10.959 --> 00:15:13.670
examples of this is when you get people


00:15:13.680 --> 00:15:15.990
who are trying to argue against an area


00:15:16.000 --> 00:15:17.670
of science, maybe vaccines, maybe


00:15:17.680 --> 00:15:19.189
climate change, maybe something less


00:15:19.199 --> 00:15:21.189
controversial. You'll often hear people


00:15:21.199 --> 00:15:23.350
say that, well, climate change is just a


00:15:23.360 --> 00:15:25.590
theory, or vaccines are just a theory,


00:15:25.600 --> 00:15:27.910
or the Big Bang is just a theory. And to


00:15:27.920 --> 00:15:31.189
a lot of people, a theory just means a


00:15:31.199 --> 00:15:34.790
loose idea. A lot of people will say,


00:15:34.800 --> 00:15:36.230
"Why isn't your car starting this


00:15:36.240 --> 00:15:38.550
morning?" Well, I've got a theory. To a


00:15:38.560 --> 00:15:40.470
scientist, a theory is a very different


00:15:40.480 --> 00:15:42.389
beast and it's tied to the ability to


00:15:42.399 --> 00:15:45.430
make testable predictions and repeated


00:15:45.440 --> 00:15:47.910
testing. There's a lot of philosophy of


00:15:47.920 --> 00:15:49.990
science. I did a philosophy of physics


00:15:50.000 --> 00:15:51.749
course at university when I was 18 and I


00:15:51.759 --> 00:15:52.949
wish I'd done it when I was at the end


00:15:52.959 --> 00:15:54.389
of my degree, not the start cuz I'd have


00:15:54.399 --> 00:15:56.389
got a lot more out of it. But there are


00:15:56.399 --> 00:15:58.230
people who have aggressively studied the


00:15:58.240 --> 00:16:01.269
philosophy of the scientific method. And


00:16:01.279 --> 00:16:03.030
even that philosophy varies a little bit


00:16:03.040 --> 00:16:05.189
discipline to discipline. A lot of other


00:16:05.199 --> 00:16:06.470
disciplines that are the experimental


00:16:06.480 --> 00:16:08.870
ones are are very much more hypothesis


00:16:08.880 --> 00:16:11.350
driven than astronomy where we say I'm


00:16:11.360 --> 00:16:12.710
interested in what this is. Let's have a


00:16:12.720 --> 00:16:14.310
look. There's not really a hypothesis. I


00:16:14.320 --> 00:16:15.749
just want to look at it and find out. At


00:16:15.759 --> 00:16:18.310
least that's how I work. But you also


00:16:18.320 --> 00:16:20.470
have this thing where at least from my


00:16:20.480 --> 00:16:21.990
philosophy, you can never prove a


00:16:22.000 --> 00:16:24.230
theory, but you can disprove a theory.


00:16:24.240 --> 00:16:26.470
What I mean by that is if you test a


00:16:26.480 --> 00:16:29.030
theory a million times and each time


00:16:29.040 --> 00:16:31.189
it's backed it up, you haven't proven


00:16:31.199 --> 00:16:32.949
that theory. You've just shown that


00:16:32.959 --> 00:16:34.550
theory is a very good approximation to


00:16:34.560 --> 00:16:36.310
what's actually happening. So take the


00:16:36.320 --> 00:16:38.470
example of me flipping a coin. I can


00:16:38.480 --> 00:16:40.470
have a theory that says coins will


00:16:40.480 --> 00:16:43.590
always land heads or tails. Test that a


00:16:43.600 --> 00:16:44.949
million times and odds are a million


00:16:44.959 --> 00:16:46.790
times you'll land heads or tails. But


00:16:46.800 --> 00:16:48.230
you've not proven that theory. You've


00:16:48.240 --> 00:16:49.269
just said it's a very close


00:16:49.279 --> 00:16:51.430
approximation to the truth. You could


00:16:51.440 --> 00:16:52.870
toss them 10 million times and one time


00:16:52.880 --> 00:16:54.069
your coin lands on its edge and


00:16:54.079 --> 00:16:54.870
balances.


00:16:54.880 --> 00:16:55.189
>> Yeah.


00:16:55.199 --> 00:16:56.710
>> That one observation. And so as long as


00:16:56.720 --> 00:16:58.230
it's well documented and is repeatable


00:16:58.240 --> 00:17:00.230
is enough to kill that theory and then


00:17:00.240 --> 00:17:01.910
you need to develop something more


00:17:01.920 --> 00:17:03.670
complex. You know


00:17:03.680 --> 00:17:05.590
>> that's where it goes from. Now that's a


00:17:05.600 --> 00:17:07.669
very roundabout way of coming back at


00:17:07.679 --> 00:17:11.829
this water being scarce myth. I think


00:17:11.839 --> 00:17:13.829
where that comes from is when you talk


00:17:13.839 --> 00:17:17.829
to me about water I am just thinking


00:17:17.839 --> 00:17:19.750
about the molecule. I'm not thinking


00:17:19.760 --> 00:17:22.630
about the physical state. So to me water


00:17:22.640 --> 00:17:24.309
can be water ice. It can be liquid


00:17:24.319 --> 00:17:26.549
water. It can be water vapor. But to


00:17:26.559 --> 00:17:28.309
most people, if you say water, they


00:17:28.319 --> 00:17:30.150
visualize liquid water. Yeah.


00:17:30.160 --> 00:17:31.750
>> Right. If if I say, "Would you like some


00:17:31.760 --> 00:17:33.029
water?" You're not expecting me to


00:17:33.039 --> 00:17:35.029
immediately start steing your face.


00:17:35.039 --> 00:17:36.549
You're expecting a glass of water.


00:17:36.559 --> 00:17:38.470
Right?


00:17:38.480 --> 00:17:40.150
What that means is that when people look


00:17:40.160 --> 00:17:41.510
out at the solar system and look


00:17:41.520 --> 00:17:43.270
everywhere else, we see this thing that


00:17:43.280 --> 00:17:45.190
Earth is the only place where we have


00:17:45.200 --> 00:17:47.669
abundant liquid water all the time on


00:17:47.679 --> 00:17:50.310
the surface. And so people have this


00:17:50.320 --> 00:17:51.830
idea that water is scarce where what


00:17:51.840 --> 00:17:54.470
they're really thinking is liquid water


00:17:54.480 --> 00:17:58.230
on the surface of an object is scarce.


00:17:58.240 --> 00:18:00.470
>> But that drove a lot of this idea that


00:18:00.480 --> 00:18:02.070
life will be scarce because life needs


00:18:02.080 --> 00:18:04.070
liquid water on Earth. The Earth's the


00:18:04.080 --> 00:18:06.230
only place with liquid water. Ergo life


00:18:06.240 --> 00:18:09.270
will be scarce. That's moved on though


00:18:09.280 --> 00:18:10.870
in about the last three or four decades.


00:18:10.880 --> 00:18:12.950
partially with the exploration of Mars


00:18:12.960 --> 00:18:15.750
where we're getting an overwhelmingly


00:18:15.760 --> 00:18:17.350
greater amount of evidence that Mars in


00:18:17.360 --> 00:18:19.110
the past was warm and wet, that it had


00:18:19.120 --> 00:18:20.470
oceans and lakes. They may have been


00:18:20.480 --> 00:18:22.310
slushy or they may have been properly


00:18:22.320 --> 00:18:24.230
liquid, but it had oceans and lakes for


00:18:24.240 --> 00:18:26.470
a long time of liquid water. And we've


00:18:26.480 --> 00:18:27.510
even got evidence that there is


00:18:27.520 --> 00:18:29.350
permanent liquid water on Mars as we're


00:18:29.360 --> 00:18:30.710
talking now in the form of liquid water


00:18:30.720 --> 00:18:33.029
in the Martian polar ice caps and you


00:18:33.039 --> 00:18:34.630
get temporal liquid water running on the


00:18:34.640 --> 00:18:36.710
surface. The other thing we found in the


00:18:36.720 --> 00:18:39.590
solar system is liquid water in


00:18:39.600 --> 00:18:41.510
astonishing abundance in the outer solar


00:18:41.520 --> 00:18:44.710
system protected by shells of ice on the


00:18:44.720 --> 00:18:47.029
icy satellites of the giant planets on


00:18:47.039 --> 00:18:48.630
the dwarf planet Pluto or inside the


00:18:48.640 --> 00:18:50.870
dwarf planet Pluto probably in the


00:18:50.880 --> 00:18:53.909
larger edge kipeld objects transepun


00:18:53.919 --> 00:18:56.230
objects maybe in other places as well


00:18:56.240 --> 00:18:58.950
even in places as small as Enceladus so


00:18:58.960 --> 00:19:01.029
there's been this revolution from the


00:19:01.039 --> 00:19:02.230
point of view of the solar system


00:19:02.240 --> 00:19:04.789
through my lifetime that actually liquid


00:19:04.799 --> 00:19:06.710
water isn't scarce.


00:19:06.720 --> 00:19:08.070
>> Coupled to the fact that the earth is


00:19:08.080 --> 00:19:10.310
actually remarkably dry as a planet that


00:19:10.320 --> 00:19:11.990
suddenly opened up people's perspectives


00:19:12.000 --> 00:19:13.750
again that the solar system is a good


00:19:13.760 --> 00:19:15.430
place to look for life and that's


00:19:15.440 --> 00:19:17.270
driving a lot of exploration missions


00:19:17.280 --> 00:19:19.990
all the Mars exploration past and future


00:19:20.000 --> 00:19:22.070
focused around that idea. the fact that


00:19:22.080 --> 00:19:23.350
we've got two missions going to the


00:19:23.360 --> 00:19:25.110
Jovian ICE satellites at the minute


00:19:25.120 --> 00:19:27.669
juice um the Jupyter moons explorer and


00:19:27.679 --> 00:19:29.510
the Europa Clipper which are to


00:19:29.520 --> 00:19:31.430
characterize those moons better to


00:19:31.440 --> 00:19:33.270
prepare for potential future landings in


00:19:33.280 --> 00:19:35.669
the 2040s or 50s to get through the ice


00:19:35.679 --> 00:19:37.669
and look at what's underneath. We've got


00:19:37.679 --> 00:19:39.350
the Dragonfly mission going out to


00:19:39.360 --> 00:19:41.270
Titan, launching in a couple of years


00:19:41.280 --> 00:19:43.190
time, probably next year. Hoping to get


00:19:43.200 --> 00:19:46.070
there 2034 that will land on the only


00:19:46.080 --> 00:19:47.669
other place that has liquid on its


00:19:47.679 --> 00:19:50.150
surface exposed to the atmosphere in the


00:19:50.160 --> 00:19:51.750
solar system and that's Titan with lakes


00:19:51.760 --> 00:19:53.990
of liquid methane and ethane. The water


00:19:54.000 --> 00:19:55.510
there is harder than granite and makes


00:19:55.520 --> 00:19:57.669
up the mountains. But there's this huge


00:19:57.679 --> 00:19:59.190
effort to explore our solar system and


00:19:59.200 --> 00:20:01.270
actually go there and look, which we


00:20:01.280 --> 00:20:03.110
can't do when we're looking at planets


00:20:03.120 --> 00:20:05.750
around the stars. And by going there and


00:20:05.760 --> 00:20:08.310
looking if there is anything there past


00:20:08.320 --> 00:20:10.630
or present eventually we'll find it.


00:20:10.640 --> 00:20:13.029
>> Now that immediately then poses a really


00:20:13.039 --> 00:20:14.950
fascinating one. So if we find life on


00:20:14.960 --> 00:20:18.150
Mars or we find life on Europa


00:20:18.160 --> 00:20:21.430
if we can look at that life and figure


00:20:21.440 --> 00:20:24.789
out its heritage figure out its DNA and


00:20:24.799 --> 00:20:26.710
I'm not a biologist so I'll be a little


00:20:26.720 --> 00:20:29.350
woolly on that. It will be very quick


00:20:29.360 --> 00:20:31.110
and very apparent whether that life has


00:20:31.120 --> 00:20:32.870
a shared origin to life on earth or


00:20:32.880 --> 00:20:34.710
whether it has a separate origin to life


00:20:34.720 --> 00:20:36.950
on earth. Now the separate origin would


00:20:36.960 --> 00:20:38.630
mean that life got started


00:20:38.640 --> 00:20:40.149
simultaneously


00:20:40.159 --> 00:20:42.310
on two objects in the same planetary


00:20:42.320 --> 00:20:45.510
system in an icy backwater of a fairly


00:20:45.520 --> 00:20:48.230
unremarkable galaxy. If it got started


00:20:48.240 --> 00:20:49.909
two places side by side, surely that


00:20:49.919 --> 00:20:51.990
means life gets started more easily than


00:20:52.000 --> 00:20:54.390
we expect. Therefore, life should be


00:20:54.400 --> 00:20:56.630
common in the universe. That would be an


00:20:56.640 --> 00:20:59.190
obvious logical continuation. The other


00:20:59.200 --> 00:21:00.870
option is that we find life elsewhere in


00:21:00.880 --> 00:21:02.230
the solar system and it has a shared


00:21:02.240 --> 00:21:03.990
heritage life on Earth. What that means


00:21:04.000 --> 00:21:06.390
is that we analyze its makeup, we find


00:21:06.400 --> 00:21:09.270
that it has DNA like Earth DNA that has


00:21:09.280 --> 00:21:11.669
a shared universal common ancestor. And


00:21:11.679 --> 00:21:13.270
what that suggests is that once life


00:21:13.280 --> 00:21:14.950
gets started somewhere, it's


00:21:14.960 --> 00:21:16.630
transmissible. You know, you've got that


00:21:16.640 --> 00:21:18.070
old thing of don't go near Earth. It's


00:21:18.080 --> 00:21:20.390
got humans. They're contagious.


00:21:20.400 --> 00:21:22.630
This is the same kind of idea. If we


00:21:22.640 --> 00:21:24.310
find life on Mars and that life has a


00:21:24.320 --> 00:21:27.270
shared heritage with life on Earth, that


00:21:27.280 --> 00:21:29.750
validates strongly supports the idea of


00:21:29.760 --> 00:21:31.990
panspermia, which I've had a student


00:21:32.000 --> 00:21:35.029
just submit his PhD thesis studying. The


00:21:35.039 --> 00:21:36.710
idea that life can transfer between the


00:21:36.720 --> 00:21:39.430
planets. Now again, if life can transfer


00:21:39.440 --> 00:21:40.870
easily enough to be found in multiple


00:21:40.880 --> 00:21:42.390
locations in the solar system from a


00:21:42.400 --> 00:21:45.430
simple single origin and maybe even


00:21:45.440 --> 00:21:46.950
Earth wasn't that origin, you know,


00:21:46.960 --> 00:21:48.310
maybe we're Martians, maybe we're


00:21:48.320 --> 00:21:51.029
Venucians or Venerians. I think that


00:21:51.039 --> 00:21:52.950
Venerian used to be the adjective for


00:21:52.960 --> 00:21:54.630
Ven adjective the right word used to be


00:21:54.640 --> 00:21:55.830
the word for Venus in the way that


00:21:55.840 --> 00:21:57.750
Martian was for Mars but it was a bit


00:21:57.760 --> 00:22:01.190
too close to venerial um because


00:22:01.200 --> 00:22:03.430
>> so they changed it but anyway um but we


00:22:03.440 --> 00:22:05.909
could be venerial creatures um we don't


00:22:05.919 --> 00:22:07.590
know but what that suggests is that if


00:22:07.600 --> 00:22:09.590
life is transferred easily and


00:22:09.600 --> 00:22:11.830
effectively once it originates life


00:22:11.840 --> 00:22:14.230
could be common in the universe so to me


00:22:14.240 --> 00:22:15.909
finding life in the solar system would


00:22:15.919 --> 00:22:17.270
be awesome I think it's eminently


00:22:17.280 --> 00:22:19.990
feasible and either way it will shed new


00:22:20.000 --> 00:22:22.310
on the commonality of life beyond the


00:22:22.320 --> 00:22:24.630
solar system. We will be looking for


00:22:24.640 --> 00:22:27.190
life like us. It is possible to imagine


00:22:27.200 --> 00:22:28.630
life that is not like us that has


00:22:28.640 --> 00:22:29.909
different requirements but that will


00:22:29.919 --> 00:22:32.630
probably be a bit harder to find and we


00:22:32.640 --> 00:22:35.190
don't know what it would be. Whereas


00:22:35.200 --> 00:22:36.950
with life like us, we know things to


00:22:36.960 --> 00:22:38.870
look for. So that makes it a bit easier


00:22:38.880 --> 00:22:41.430
for us to look for life like us. It also


00:22:41.440 --> 00:22:44.630
makes it, I'd say, a little bit stronger


00:22:44.640 --> 00:22:46.950
as a case when you're asking for funding


00:22:46.960 --> 00:22:48.230
because you can say, well, we already


00:22:48.240 --> 00:22:50.390
know this kind of life can exist. So,


00:22:50.400 --> 00:22:51.750
we're going to look at a place where the


00:22:51.760 --> 00:22:52.950
conditions are similar to where we know


00:22:52.960 --> 00:22:54.870
it does exist and see if we find it


00:22:54.880 --> 00:22:56.070
there as well.


00:22:56.080 --> 00:22:58.710
>> Okay, let's take a short break. Uh, this


00:22:58.720 --> 00:23:01.110
is Space Nuts with Andrew Dunley and


00:23:01.120 --> 00:23:04.630
Professor Jonty Horner.


00:23:04.640 --> 00:23:06.230
Let's take a short break from the show


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00:24:53.440 --> 00:24:57.269
>> I'm going to step off the mount.


00:24:57.279 --> 00:25:02.630
That's one small step for man,


00:25:02.640 --> 00:25:05.590
one leap for mankind.


00:25:05.600 --> 00:25:07.510
>> Space nuts.


00:25:07.520 --> 00:25:09.269
>> It's not Professor Fred Watson at the


00:25:09.279 --> 00:25:10.870
moment. He's away. We've got Professor


00:25:10.880 --> 00:25:12.230
Jonty Hoer and we're talking


00:25:12.240 --> 00:25:15.110
astrobiology in this uh little special


00:25:15.120 --> 00:25:18.230
edition. Um, one thing I heard in the


00:25:18.240 --> 00:25:19.990
news recently, I think Fred and I talked


00:25:20.000 --> 00:25:21.909
about it was uh, you know, we've been


00:25:21.919 --> 00:25:23.669
talking about water and if you want to


00:25:23.679 --> 00:25:25.750
find the people, find the water, that


00:25:25.760 --> 00:25:27.430
sort of thing. But there was one


00:25:27.440 --> 00:25:29.990
particular study that uh was recently


00:25:30.000 --> 00:25:31.430
released that says if you want to find


00:25:31.440 --> 00:25:34.070
the people, find the coal. What do you


00:25:34.080 --> 00:25:35.430
think of that theory?


00:25:35.440 --> 00:25:37.190
>> That's an interesting one. So that's the


00:25:37.200 --> 00:25:39.269
idea that if you want to find somebody


00:25:39.279 --> 00:25:40.710
to talk to,


00:25:40.720 --> 00:25:42.230
>> there needs to be something to fuel an


00:25:42.240 --> 00:25:44.149
industrial revolution. And again, this


00:25:44.159 --> 00:25:45.029
is


00:25:45.039 --> 00:25:46.870
>> I think science fiction sometimes does


00:25:46.880 --> 00:25:48.710
this really ask this really interesting


00:25:48.720 --> 00:25:50.390
questions of


00:25:50.400 --> 00:25:53.990
>> almost is the path that we have followed


00:25:54.000 --> 00:25:55.669
the one that everyone will follow? you


00:25:55.679 --> 00:25:57.750
know because there's so much to some


00:25:57.760 --> 00:25:59.909
degree randomness in the things that


00:25:59.919 --> 00:26:02.470
have driven our knowledge and our


00:26:02.480 --> 00:26:04.470
development of things you know um


00:26:04.480 --> 00:26:06.470
obviously a good example is a famous


00:26:06.480 --> 00:26:08.870
myth about penicellin that if um you


00:26:08.880 --> 00:26:10.549
leave your bread out and it goes moldy


00:26:10.559 --> 00:26:13.190
that makes your pus more effective um


00:26:13.200 --> 00:26:15.830
and that was an incredible scientific


00:26:15.840 --> 00:26:17.590
re revolution driven by that discovery


00:26:17.600 --> 00:26:19.510
there


00:26:19.520 --> 00:26:21.430
who's to say other civilizations would


00:26:21.440 --> 00:26:22.870
have the same discoveries in the same


00:26:22.880 --> 00:26:26.710
order now to advance. We have required


00:26:26.720 --> 00:26:29.830
advances in energy in order to allow us


00:26:29.840 --> 00:26:32.710
to better develop technology and develop


00:26:32.720 --> 00:26:34.310
the things that everything's made of.


00:26:34.320 --> 00:26:36.070
You know, if we didn't have anything


00:26:36.080 --> 00:26:38.789
that you could burn, it would be very


00:26:38.799 --> 00:26:40.710
very challenging to smelt metal. If you


00:26:40.720 --> 00:26:42.390
couldn't smelt metal, how do you build


00:26:42.400 --> 00:26:43.430
electronics?


00:26:43.440 --> 00:26:45.350
>> You are spot on. That's exactly what the


00:26:45.360 --> 00:26:48.470
article was all about. And uh the bottom


00:26:48.480 --> 00:26:51.269
line was uh that because of the timing


00:26:51.279 --> 00:26:55.430
required, it lessens the likelihood of


00:26:55.440 --> 00:26:59.269
us finding uh people like us. It reduces


00:26:59.279 --> 00:27:00.149
the odds.


00:27:00.159 --> 00:27:02.230
>> And this is where there's a difference


00:27:02.240 --> 00:27:04.149
between the search for extraterrestrial


00:27:04.159 --> 00:27:06.230
intelligence and the search for life. So


00:27:06.240 --> 00:27:07.669
the search for extraterrestrial


00:27:07.679 --> 00:27:09.430
intelligence is like a subset of the


00:27:09.440 --> 00:27:12.070
search for life. Search for life is a


00:27:12.080 --> 00:27:14.149
search for bacteria as much as it's the


00:27:14.159 --> 00:27:17.430
search for communicative aliens. And


00:27:17.440 --> 00:27:19.190
there's been a lot of stuff written and


00:27:19.200 --> 00:27:22.149
discussed about whether evolutionary


00:27:22.159 --> 00:27:24.230
quirks have benefited us by being here,


00:27:24.240 --> 00:27:26.070
you know, in terms of we're a social


00:27:26.080 --> 00:27:27.590
communal animal that shares resources


00:27:27.600 --> 00:27:30.149
and shares learning. There have been


00:27:30.159 --> 00:27:31.669
other ones like that from Aunt Collins.


00:27:31.679 --> 00:27:34.310
And I'm listening to a very chill and


00:27:34.320 --> 00:27:38.230
very silly um lit RPG. I think would be


00:27:38.240 --> 00:27:39.830
the description of the genre book called


00:27:39.840 --> 00:27:41.350
series of books called Chrysis at the


00:27:41.360 --> 00:27:44.230
minute where a young boy who dies for


00:27:44.240 --> 00:27:47.269
reasons is reincarnated in the b body of


00:27:47.279 --> 00:27:50.230
an ant. And it's a book about him as an


00:27:50.240 --> 00:27:52.070
ant and his life in the colony and stuff


00:27:52.080 --> 00:27:55.350
and it's bonkers but um you've got an


00:27:55.360 --> 00:27:57.590
advanced social species there and he


00:27:57.600 --> 00:27:59.190
finds ways without too many spoilers of


00:27:59.200 --> 00:28:00.389
giving them intelligence and what


00:28:00.399 --> 00:28:01.909
happens afterwards.


00:28:01.919 --> 00:28:03.430
>> There's a few species in the history of


00:28:03.440 --> 00:28:05.350
earth that have that kind of communal


00:28:05.360 --> 00:28:07.750
sharing of information thing. we're the


00:28:07.760 --> 00:28:09.029
only ones that have achieved what we've


00:28:09.039 --> 00:28:11.669
achieved. Some arguments are that's down


00:28:11.679 --> 00:28:13.909
to the development of language and our


00:28:13.919 --> 00:28:16.070
ability to produce complex language and


00:28:16.080 --> 00:28:17.669
also the opposable thumb being quite


00:28:17.679 --> 00:28:20.149
important. So there's a lot of stuff


00:28:20.159 --> 00:28:22.630
that there are many steps between the


00:28:22.640 --> 00:28:24.230
development of life and the development


00:28:24.240 --> 00:28:26.630
of intelligence and the development of


00:28:26.640 --> 00:28:28.389
intelligence itself doesn't necessarily


00:28:28.399 --> 00:28:29.990
mean the development of technological


00:28:30.000 --> 00:28:31.750
intelligence. You know, a lot of


00:28:31.760 --> 00:28:33.590
discussions about all the things octopi


00:28:33.600 --> 00:28:36.710
or octopods or octopidles octopi could


00:28:36.720 --> 00:28:38.950
achieve if they lived for more than 3


00:28:38.960 --> 00:28:41.029
years and if they were a social animal.


00:28:41.039 --> 00:28:42.389
They've got incredible brains. We're


00:28:42.399 --> 00:28:44.230
learning more and more about some of the


00:28:44.240 --> 00:28:47.430
brain power that birds exhibit.


00:28:47.440 --> 00:28:48.630
But none of them have become


00:28:48.640 --> 00:28:50.230
technological intelligences. And the


00:28:50.240 --> 00:28:52.549
search for extraterrestrial intelligence


00:28:52.559 --> 00:28:55.110
is very much centered around a


00:28:55.120 --> 00:28:58.389
technology that allows civilizations to


00:28:58.399 --> 00:29:00.710
communicate with one another. that


00:29:00.720 --> 00:29:02.549
therefore is based on many prerequisites


00:29:02.559 --> 00:29:03.830
that lead to the development of the


00:29:03.840 --> 00:29:05.510
ability to broadcast your existence to


00:29:05.520 --> 00:29:07.669
the cosmos. The coal thing's


00:29:07.679 --> 00:29:09.350
interesting. I mean, I'm not


00:29:09.360 --> 00:29:13.669
sufficiently archaeologically minded to


00:29:13.679 --> 00:29:16.149
be able to say with certainty that


00:29:16.159 --> 00:29:18.149
without coal, we wouldn't have got here.


00:29:18.159 --> 00:29:19.669
And the reason that I express caution on


00:29:19.679 --> 00:29:22.470
that coal and oil is that we have things


00:29:22.480 --> 00:29:24.950
that people burn for energy that are not


00:29:24.960 --> 00:29:26.389
coal and oil. M


00:29:26.399 --> 00:29:28.070
>> and I think a lot of the smelting that


00:29:28.080 --> 00:29:29.430
was done, and I may be wrong on this


00:29:29.440 --> 00:29:30.710
because I'm not an archaeologist. I just


00:29:30.720 --> 00:29:32.710
pick bits up when my partner's watching


00:29:32.720 --> 00:29:34.070
time team and things like that. She


00:29:34.080 --> 00:29:36.230
loves her archaeology, so I get a little


00:29:36.240 --> 00:29:38.389
bit of that as a very thin veneer. But I


00:29:38.399 --> 00:29:39.750
think a lot of the times when people


00:29:39.760 --> 00:29:41.909
smelted metals, talking about bronze and


00:29:41.919 --> 00:29:43.990
iron, they used wood or they use


00:29:44.000 --> 00:29:45.830
charcoal, which is a byproduct of


00:29:45.840 --> 00:29:46.870
burning wood.


00:29:46.880 --> 00:29:47.909
>> Yeah.


00:29:47.919 --> 00:29:50.549
So maybe it would be more challenging


00:29:50.559 --> 00:29:53.269
without the easy available energy of


00:29:53.279 --> 00:29:55.110
fossil fuels, without the easy available


00:29:55.120 --> 00:29:58.149
energy of coal, oil, gas. But it might


00:29:58.159 --> 00:29:59.110
be that that wouldn't be an


00:29:59.120 --> 00:30:00.630
insurmountable hurdle, but it would


00:30:00.640 --> 00:30:01.909
result in a different path being


00:30:01.919 --> 00:30:04.950
followed. You know, what would we get in


00:30:04.960 --> 00:30:06.549
terms of seam power if we were using


00:30:06.559 --> 00:30:08.789
wood and if we were using charcoal


00:30:08.799 --> 00:30:11.590
rather than other things? Would it lead


00:30:11.600 --> 00:30:13.269
to an earlier adoption of renewable


00:30:13.279 --> 00:30:15.430
energy in the form of wind power which


00:30:15.440 --> 00:30:17.590
was actually being used for hundreds of


00:30:17.600 --> 00:30:18.789
years? You go back to Europe and you see


00:30:18.799 --> 00:30:20.470
the windmills people use


00:30:20.480 --> 00:30:22.789
>> and watermills people's use.


00:30:22.799 --> 00:30:26.549
>> So I I don't know whether


00:30:26.559 --> 00:30:28.549
and this is a problem with all of


00:30:28.559 --> 00:30:30.389
astrobiology and it's a problem with a


00:30:30.399 --> 00:30:31.430
lot of the stuff that I'll talk about


00:30:31.440 --> 00:30:33.029
later about what makes a planet more


00:30:33.039 --> 00:30:35.269
suitable or less suitable. People have


00:30:35.279 --> 00:30:37.669
this tendency to find something that is


00:30:37.679 --> 00:30:40.070
unusual about us and there's a lot


00:30:40.080 --> 00:30:41.269
that's unusual about us. I mean there's


00:30:41.279 --> 00:30:42.549
a lot that's unusual about me and I hold


00:30:42.559 --> 00:30:45.110
my hand up about that. But they find


00:30:45.120 --> 00:30:47.269
things that are unusual


00:30:47.279 --> 00:30:49.029
and they say we are as far as we know


00:30:49.039 --> 00:30:50.470
unique in the cosmos. We are a


00:30:50.480 --> 00:30:51.990
technologically advanced civilization


00:30:52.000 --> 00:30:54.470
able to have this discussion.


00:30:54.480 --> 00:30:56.389
There has to be a reason that we're


00:30:56.399 --> 00:30:59.750
here. Everything that is unusual quite


00:30:59.760 --> 00:31:01.830
often gets held up as could this be the


00:31:01.840 --> 00:31:03.990
switch? If you didn't have this, we


00:31:04.000 --> 00:31:06.389
would not be here. And I tend to view


00:31:06.399 --> 00:31:08.149
them not as an on-off switch, but as a


00:31:08.159 --> 00:31:10.549
slider. They're like, and again, a


00:31:10.559 --> 00:31:12.070
gaming analogy would be varying the


00:31:12.080 --> 00:31:14.310
difficulty on your game. Some games,


00:31:14.320 --> 00:31:16.470
it's very kind of onoff, hard mode, easy


00:31:16.480 --> 00:31:18.230
mode. Others, particularly some of the


00:31:18.240 --> 00:31:20.230
role playing type games people play,


00:31:20.240 --> 00:31:22.630
have sliders for everything. And so, you


00:31:22.640 --> 00:31:26.230
can change things to the nth degree to


00:31:26.240 --> 00:31:28.549
tweak the challenge level. And I think


00:31:28.559 --> 00:31:30.070
all of these things like the existence


00:31:30.080 --> 00:31:34.230
of coal that get proposed as being a


00:31:34.240 --> 00:31:36.149
boundary, as being something that would


00:31:36.159 --> 00:31:38.149
be a block if you didn't have it, are


00:31:38.159 --> 00:31:39.430
actually probably more like one of those


00:31:39.440 --> 00:31:40.710
sliders. They're things that can


00:31:40.720 --> 00:31:42.230
facilitate,


00:31:42.240 --> 00:31:44.310
but it's really interesting to discuss


00:31:44.320 --> 00:31:45.990
them because we don't know how big a


00:31:46.000 --> 00:31:47.990
filter they are. We don't know how big a


00:31:48.000 --> 00:31:50.310
hurdle they are without digging into it


00:31:50.320 --> 00:31:51.750
more. And the more we can suggest these


00:31:51.760 --> 00:31:53.350
things, the more we can narrow them


00:31:53.360 --> 00:31:55.110
down. Ultimately, the only way we can


00:31:55.120 --> 00:31:57.350
finally test them is when we get a


00:31:57.360 --> 00:31:59.590
response to us, when we find


00:31:59.600 --> 00:32:02.549
technologically advanced life and then


00:32:02.559 --> 00:32:04.470
we learn about their heritage. What path


00:32:04.480 --> 00:32:07.269
did they follow? Did they invent fire


00:32:07.279 --> 00:32:10.470
before the wheel? Did they invent modern


00:32:10.480 --> 00:32:13.990
medicine before fire? And I've seen


00:32:14.000 --> 00:32:17.509
there's a fabulous famous old thread, I


00:32:17.519 --> 00:32:18.870
don't know, it wasn't from Reddit, it


00:32:18.880 --> 00:32:20.630
predates Reddit, but from one of the old


00:32:20.640 --> 00:32:24.789
messaging boards that talks about humans


00:32:24.799 --> 00:32:27.029
as the horror movie monsters of the


00:32:27.039 --> 00:32:29.750
universe. Because we always in science


00:32:29.760 --> 00:32:31.269
fiction, all the monsters we face, all


00:32:31.279 --> 00:32:33.190
the aliens we face are usually more


00:32:33.200 --> 00:32:35.110
something than us. And we overcome


00:32:35.120 --> 00:32:37.430
incredible odds to beat them. But this


00:32:37.440 --> 00:32:38.870
is taking the other perspective of


00:32:38.880 --> 00:32:40.230
another species kind of looking at us


00:32:40.240 --> 00:32:41.590
and going, "Those humans are


00:32:41.600 --> 00:32:42.950
terrifying." And it's listing all the


00:32:42.960 --> 00:32:43.990
ways we are. You know, we're an


00:32:44.000 --> 00:32:46.470
exhaustion hunter. We didn't beat things


00:32:46.480 --> 00:32:48.230
by speed or anything. We'd follow them


00:32:48.240 --> 00:32:51.430
until they died of exhaustion because we


00:32:51.440 --> 00:32:54.070
can go longer than they can. We're un


00:32:54.080 --> 00:32:55.269
they were saying, you know, it's the


00:32:55.279 --> 00:32:57.110
only intelligent technological species


00:32:57.120 --> 00:32:58.710
that invented amputation before


00:32:58.720 --> 00:33:00.630
painkillers.


00:33:00.640 --> 00:33:02.070
>> You know, we've got things like this


00:33:02.080 --> 00:33:04.870
that are very bizarre about us. So that


00:33:04.880 --> 00:33:07.350
takes this perspective I've got of these


00:33:07.360 --> 00:33:09.350
things are a hurdle and you develop


00:33:09.360 --> 00:33:11.669
things you know that things are not


00:33:11.679 --> 00:33:12.950
onoff switch but they're more of a


00:33:12.960 --> 00:33:16.070
slider and the idea of will things


00:33:16.080 --> 00:33:18.310
naturally be developed in the same order


00:33:18.320 --> 00:33:19.830
and turns it around and said what would


00:33:19.840 --> 00:33:22.549
another species think looking at us and


00:33:22.559 --> 00:33:23.990
I always find that really good fun and


00:33:24.000 --> 00:33:25.590
it's effectively leads to the thing that


00:33:25.600 --> 00:33:28.389
humans are space and we're this terri


00:33:28.399 --> 00:33:31.029
terrifying weird little species and


00:33:31.039 --> 00:33:33.430
maybe that's what it'll turn out to


00:33:33.440 --> 00:33:36.230
Well, it yeah, look, I don't uh I don't


00:33:36.240 --> 00:33:39.029
dispute that because look how we treat


00:33:39.039 --> 00:33:42.389
each other or have treated each other um


00:33:42.399 --> 00:33:45.509
since civilization began. Basically, uh


00:33:45.519 --> 00:33:47.269
I I don't think you could add up how


00:33:47.279 --> 00:33:48.870
many wars we've fought against each


00:33:48.880 --> 00:33:50.549
other.


00:33:50.559 --> 00:33:53.110
I I don't think that would stop if we


00:33:53.120 --> 00:33:55.110
found another intelligent life form. I


00:33:55.120 --> 00:33:57.029
don't think we'd go in saying, "Hi, hey,


00:33:57.039 --> 00:33:59.350
we're really nice." I I got a feeling


00:33:59.360 --> 00:34:01.110
we'd, you know, it'd be a bit


00:34:01.120 --> 00:34:03.110
adversarial.


00:34:03.120 --> 00:34:05.190
>> It It's a really It is a really


00:34:05.200 --> 00:34:06.310
interesting one. It's one of the things


00:34:06.320 --> 00:34:08.710
that people factor into a lot of the


00:34:08.720 --> 00:34:11.190
discussions about the the rights and


00:34:11.200 --> 00:34:14.869
wrongs of active SETI. So active SETI is


00:34:14.879 --> 00:34:16.310
sending out a message saying, "Hi, we're


00:34:16.320 --> 00:34:18.149
here. Please talk to us." Whereas


00:34:18.159 --> 00:34:19.750
passive SETI is listening for people


00:34:19.760 --> 00:34:21.030
saying, "Please turn neighbors off.


00:34:21.040 --> 00:34:22.230
We're sick of seeing it." You know,


00:34:22.240 --> 00:34:23.829
they're effectively the two ways you can


00:34:23.839 --> 00:34:27.109
do SETI. There are a lot of people in


00:34:27.119 --> 00:34:28.629
the past that have argued that active


00:34:28.639 --> 00:34:30.149
set is a bad idea because it will


00:34:30.159 --> 00:34:31.669
attract the wrong kind of attention.


00:34:31.679 --> 00:34:33.349
>> Well, Steven Hawking certainly thought


00:34:33.359 --> 00:34:33.990
that.


00:34:34.000 --> 00:34:37.030
>> Um, and throwing no shade, I think the


00:34:37.040 --> 00:34:38.950
great Mark Camode, who's a film reviewer


00:34:38.960 --> 00:34:41.669
in the UK, um, often says, you know,


00:34:41.679 --> 00:34:43.430
other opinions are available. They're


00:34:43.440 --> 00:34:45.669
wrong, but they are available. I mean,


00:34:45.679 --> 00:34:47.349
this, I think, is a case of that. I


00:34:47.359 --> 00:34:49.909
think if any for me, and I will admit


00:34:49.919 --> 00:34:51.589
I'm an optimist. I'm also not exactly


00:34:51.599 --> 00:34:54.149
the world's most aggressive person, but


00:34:54.159 --> 00:34:55.909
for me, if you have survived as a


00:34:55.919 --> 00:34:58.310
species for long enough to be a thriving


00:34:58.320 --> 00:35:00.150
civilization to the point of wanting to


00:35:00.160 --> 00:35:02.150
communicate to the upsc upstarts that


00:35:02.160 --> 00:35:04.150
are broadcasting, you know, Big Brother


00:35:04.160 --> 00:35:06.550
and all the rest of it to the universe,


00:35:06.560 --> 00:35:08.390
that suggests that to some degree you've


00:35:08.400 --> 00:35:10.950
overcome your martiality. Um because I


00:35:10.960 --> 00:35:13.430
think for us to survive to the point


00:35:13.440 --> 00:35:15.829
where we're moving out into the stars


00:35:15.839 --> 00:35:17.510
will require us not to first wipe


00:35:17.520 --> 00:35:19.190
ourselves out. And the more advanced you


00:35:19.200 --> 00:35:22.230
get, the more you disperse probably,


00:35:22.240 --> 00:35:24.790
fingers crossed, hopefully, the less


00:35:24.800 --> 00:35:26.310
likely that becomes. Now, we look at the


00:35:26.320 --> 00:35:27.589
world around us today, and without


00:35:27.599 --> 00:35:29.030
digging into politics, there's always


00:35:29.040 --> 00:35:30.950
something nasty going on. There's


00:35:30.960 --> 00:35:32.470
>> many, many tragedies that are both


00:35:32.480 --> 00:35:34.230
frontline in the news and forgotten by


00:35:34.240 --> 00:35:38.069
the news. But I saw a great article few


00:35:38.079 --> 00:35:40.870
years ago that was arguing that you know


00:35:40.880 --> 00:35:42.390
when was the worst time to ever live and


00:35:42.400 --> 00:35:44.230
saying that actually despite the fact


00:35:44.240 --> 00:35:46.230
that all this war all this aggression


00:35:46.240 --> 00:35:48.870
all this violence is so front and center


00:35:48.880 --> 00:35:50.870
this is actually the safest era to live


00:35:50.880 --> 00:35:53.750
in that humanity's ever experienced the


00:35:53.760 --> 00:35:55.910
number of people dying before their time


00:35:55.920 --> 00:35:58.630
dying before they reach scessians is


00:35:58.640 --> 00:36:00.390
lower per thousand people up 100


00:36:00.400 --> 00:36:02.870
thousand people than ever before you


00:36:02.880 --> 00:36:04.470
have a much lower chance as an average


00:36:04.480 --> 00:36:05.990
person of ever fighting in a war have


00:36:06.000 --> 00:36:08.390
ever been murdered or assaulted.


00:36:08.400 --> 00:36:10.550
>> So, we're already moving that way if it


00:36:10.560 --> 00:36:12.630
doesn't feel like it. And so, to me,


00:36:12.640 --> 00:36:15.589
with that optimistic viewpoint, I would


00:36:15.599 --> 00:36:17.910
like to think that there is no reason


00:36:17.920 --> 00:36:19.670
for conflict and no reason for friction.


00:36:19.680 --> 00:36:22.069
And I think a lot of the arguments that


00:36:22.079 --> 00:36:25.270
humanity's future encounters with aliens


00:36:25.280 --> 00:36:28.310
must by necessity be violent is telling


00:36:28.320 --> 00:36:29.670
you more about people than it's telling


00:36:29.680 --> 00:36:31.030
you about aliens because it's saying


00:36:31.040 --> 00:36:32.950
when we look in the mirror, we see the


00:36:32.960 --> 00:36:35.349
angry snarling tribalist. rather than


00:36:35.359 --> 00:36:38.069
the rational modern human that is a


00:36:38.079 --> 00:36:40.550
veneer on top. We're still a tribal


00:36:40.560 --> 00:36:43.190
species. We're still the product of our


00:36:43.200 --> 00:36:45.589
evolution. And society is a veneer that


00:36:45.599 --> 00:36:48.950
we put on top of that as we learn to be


00:36:48.960 --> 00:36:50.390
better, to be the kind of thinking


00:36:50.400 --> 00:36:54.069
social ape, I guess. And the evidence is


00:36:54.079 --> 00:36:55.510
that over time we're getting better at


00:36:55.520 --> 00:36:57.430
that. Even though we're now more capable


00:36:57.440 --> 00:36:59.270
of killing each other than we ever were


00:36:59.280 --> 00:36:59.990
before.


00:37:00.000 --> 00:37:00.310
>> Yeah.


00:37:00.320 --> 00:37:01.829
>> We're doing it less often.


00:37:01.839 --> 00:37:03.910
>> Yes, we are. All right. All right, we'll


00:37:03.920 --> 00:37:05.349
take a quick breather because I want to


00:37:05.359 --> 00:37:10.069
get into the um the area of u finding


00:37:10.079 --> 00:37:12.790
this life beyond our solar system. How


00:37:12.800 --> 00:37:14.230
how are we going to do it, where we're


00:37:14.240 --> 00:37:15.430
going to look, and what we've got to


00:37:15.440 --> 00:37:17.190
look for. That's all coming up on this


00:37:17.200 --> 00:37:21.670
edition of Space Nuts.


00:37:21.680 --> 00:37:23.510
>> Roger. Also,


00:37:23.520 --> 00:37:24.630
>> Space Nuts.


00:37:24.640 --> 00:37:26.790
>> So, Jotty, look, lead the way. Where do


00:37:26.800 --> 00:37:28.630
you want to go from here? We got to uh


00:37:28.640 --> 00:37:31.270
this is our final segment. So, um I


00:37:31.280 --> 00:37:33.349
suppose if you're going to try and find


00:37:33.359 --> 00:37:36.950
life beyond our solar system, uh you got


00:37:36.960 --> 00:37:39.750
to find the right environment, um you


00:37:39.760 --> 00:37:41.670
know, rocky planet, habitable zone


00:37:41.680 --> 00:37:43.990
perhaps, um


00:37:44.000 --> 00:37:45.829
>> and and there's a lot more to it than


00:37:45.839 --> 00:37:48.230
that. It's not just a planet with


00:37:48.240 --> 00:37:51.829
perhaps liquid water on its surface.


00:37:51.839 --> 00:37:53.750
There's you got to have, I suppose, the


00:37:53.760 --> 00:37:55.430
right kind of star. You don't want a red


00:37:55.440 --> 00:37:57.270
dwarf because you probably just, you


00:37:57.280 --> 00:38:00.390
know, get really bad sunburn. Uh there's


00:38:00.400 --> 00:38:02.310
a lot to take into account.


00:38:02.320 --> 00:38:03.829
>> There's a huge amount of depth to it.


00:38:03.839 --> 00:38:05.750
And I think as we saw with the previous


00:38:05.760 --> 00:38:07.349
episode, we could have talked another


00:38:07.359 --> 00:38:09.030
hour and we could have talked another


00:38:09.040 --> 00:38:10.310
week. To be honest, when we're talking


00:38:10.320 --> 00:38:12.950
about this stuff, one of the things I


00:38:12.960 --> 00:38:15.670
most adore about science is the infinite


00:38:15.680 --> 00:38:17.510
complexity. So you ask a question when


00:38:17.520 --> 00:38:18.950
you get an answer. That isn't it. But


00:38:18.960 --> 00:38:21.030
you get another 10 questions. And the


00:38:21.040 --> 00:38:22.470
more you know about a subject, the more


00:38:22.480 --> 00:38:24.230
complexity there is. To me, that's just


00:38:24.240 --> 00:38:26.550
a wonder. And that's fascinating. And


00:38:26.560 --> 00:38:28.150
this is a really good example of that.


00:38:28.160 --> 00:38:32.230
Now, one of my strongest arguments


00:38:32.240 --> 00:38:36.630
through my career has been that we can't


00:38:36.640 --> 00:38:37.750
just when we're trying to think about


00:38:37.760 --> 00:38:39.030
where we're going to search for life


00:38:39.040 --> 00:38:41.670
beyond the solar system, use a habitable


00:38:41.680 --> 00:38:43.349
zone and that's it. You know, it seems


00:38:43.359 --> 00:38:45.990
like a lot of coverage and a lot of


00:38:46.000 --> 00:38:48.150
papers just go earthlike planet found in


00:38:48.160 --> 00:38:50.870
the habitable zone. Wee and and that's


00:38:50.880 --> 00:38:53.270
about it. Now, the habitable zone has


00:38:53.280 --> 00:38:55.589
become a really effective communication


00:38:55.599 --> 00:38:56.950
tool in much the same way the Drake


00:38:56.960 --> 00:38:59.270
equation has. The Drake equation is this


00:38:59.280 --> 00:39:00.950
fabulous tool with all the sliders where


00:39:00.960 --> 00:39:03.510
you can make your own inhabited universe


00:39:03.520 --> 00:39:05.670
with lots of few aliens by varying the


00:39:05.680 --> 00:39:08.310
variables. The habitable zone has become


00:39:08.320 --> 00:39:10.390
another of these catch all kind of


00:39:10.400 --> 00:39:12.310
visualizations and it's born of the idea


00:39:12.320 --> 00:39:14.390
that life needs liquid water


00:39:14.400 --> 00:39:17.270
>> with the implicit extension of that that


00:39:17.280 --> 00:39:19.030
life needs liquid water on a planet's


00:39:19.040 --> 00:39:22.390
surface. Now that's initially motivated


00:39:22.400 --> 00:39:23.750
by the fact that the earth is the only


00:39:23.760 --> 00:39:25.990
place with life and back when this was


00:39:26.000 --> 00:39:27.109
being discussed the only place with


00:39:27.119 --> 00:39:29.349
liquid water that we knew. So therefore


00:39:29.359 --> 00:39:31.190
it was natural to say you need surface


00:39:31.200 --> 00:39:33.349
liquid water. As we discussed earlier


00:39:33.359 --> 00:39:34.870
there are plenty of places in the solar


00:39:34.880 --> 00:39:36.870
system that do not have liquid water on


00:39:36.880 --> 00:39:38.950
the surface but do have it underneath.


00:39:38.960 --> 00:39:40.950
They've got soft centers. But the


00:39:40.960 --> 00:39:43.750
habitable zone says you need liquid


00:39:43.760 --> 00:39:45.990
water on the surface of a planet for


00:39:46.000 --> 00:39:47.589
that planet to be considered suitable


00:39:47.599 --> 00:39:49.910
for life to be habitable.


00:39:49.920 --> 00:39:52.550
Now, that isn't entirely true, but for


00:39:52.560 --> 00:39:54.390
the purposes of this, it's still useful


00:39:54.400 --> 00:39:57.670
because life buried beneath ice is so


00:39:57.680 --> 00:39:59.030
hard to find that we can't find it in


00:39:59.040 --> 00:40:00.470
our own solar system because the ice is


00:40:00.480 --> 00:40:02.390
in the way. We wouldn't have a chance to


00:40:02.400 --> 00:40:03.990
run planets around other stars. So, even


00:40:04.000 --> 00:40:05.990
though I think the habitable zone is a


00:40:06.000 --> 00:40:07.990
big oversimplification, I see merit to


00:40:08.000 --> 00:40:10.310
it because life on a planet's surface


00:40:10.320 --> 00:40:13.190
with only atmosphere above is much more


00:40:13.200 --> 00:40:15.349
likely to be detectable than life burden


00:40:15.359 --> 00:40:16.950
the interior. So, fair enough, we'll go


00:40:16.960 --> 00:40:19.270
with it. The idea of the habitable zone


00:40:19.280 --> 00:40:21.109
though is that the closer you are to a


00:40:21.119 --> 00:40:22.870
star, the hotter you are. The further


00:40:22.880 --> 00:40:24.630
away you are, the cooler you are. And


00:40:24.640 --> 00:40:25.990
just like Goldilocks and the three


00:40:26.000 --> 00:40:27.270
bears, which why it's often called the


00:40:27.280 --> 00:40:28.790
Goldilock zone, there's a place where


00:40:28.800 --> 00:40:30.470
it's just right. It's not too hot, not


00:40:30.480 --> 00:40:31.670
too cold,


00:40:31.680 --> 00:40:32.870
>> and therefore there could be liquid


00:40:32.880 --> 00:40:35.190
water on the surface of the planet. Now,


00:40:35.200 --> 00:40:36.790
a lot of the time when people say a


00:40:36.800 --> 00:40:39.670
planet is in the habitable zone,


00:40:39.680 --> 00:40:42.230
that's often taken as meaning that


00:40:42.240 --> 00:40:44.550
planet could and potentially will have


00:40:44.560 --> 00:40:46.390
liquid water on the surface. But


00:40:46.400 --> 00:40:48.630
actually what it's saying is if you took


00:40:48.640 --> 00:40:51.589
the Earth as the Earth is today and put


00:40:51.599 --> 00:40:53.670
it in that system, would it still look


00:40:53.680 --> 00:40:54.950
like the Earth? Would it have liquid


00:40:54.960 --> 00:40:58.390
water on its surface? Now we've extended


00:40:58.400 --> 00:41:00.230
a bit beyond that. There are a couple of


00:41:00.240 --> 00:41:01.829
fabulous papers bit more than a decade


00:41:01.839 --> 00:41:03.990
old now that set what are our very


00:41:04.000 --> 00:41:05.910
contemporary scientific mathematical


00:41:05.920 --> 00:41:08.069
definitions of the habitable zone that


00:41:08.079 --> 00:41:10.390
people use for their papers. And they


00:41:10.400 --> 00:41:12.470
take the flux from the star, take into


00:41:12.480 --> 00:41:13.750
account the different colors of the


00:41:13.760 --> 00:41:16.150
stars. And there are two versions.


00:41:16.160 --> 00:41:17.990
There's the optimistic and conservative


00:41:18.000 --> 00:41:20.790
versions where the optimistic version is


00:41:20.800 --> 00:41:22.950
a wider set of distances and the


00:41:22.960 --> 00:41:24.550
conservative version is a smaller set of


00:41:24.560 --> 00:41:27.190
distances. But it effectively uses Venus


00:41:27.200 --> 00:41:29.510
and Mars as a roughing edge in our solar


00:41:29.520 --> 00:41:31.109
system and then scales that window up


00:41:31.119 --> 00:41:32.950
and down depending on the kind of star


00:41:32.960 --> 00:41:34.150
you're around.


00:41:34.160 --> 00:41:37.349
>> But that illustrates immediately


00:41:37.359 --> 00:41:39.270
that this is an oversimplification


00:41:39.280 --> 00:41:40.790
because you can do a thought experiment.


00:41:40.800 --> 00:41:42.870
Let's take our solar system. Venus is


00:41:42.880 --> 00:41:45.030
way too hot. Mars is way too cold and


00:41:45.040 --> 00:41:46.710
the Earth is just right. All well and


00:41:46.720 --> 00:41:49.349
good. Swap the Earth. Sorry, swap Mars


00:41:49.359 --> 00:41:51.430
and Venus around. If you put Venus where


00:41:51.440 --> 00:41:53.670
Mars is, Venus's thick atmosphere and


00:41:53.680 --> 00:41:54.790
greenhouse effect wouldn't mean it would


00:41:54.800 --> 00:41:56.069
be warm enough liquid water on the


00:41:56.079 --> 00:41:57.510
surface. It wouldn't have cooled as much


00:41:57.520 --> 00:42:01.349
as Mars. So Venus would be habitable on


00:42:01.359 --> 00:42:04.150
the surface outside the habitable zone.


00:42:04.160 --> 00:42:06.069
If you put Mars where Venus is, with its


00:42:06.079 --> 00:42:07.829
very thin and tenuous atmosphere, it


00:42:07.839 --> 00:42:10.309
doesn't have much greenhouse effect at


00:42:10.319 --> 00:42:12.550
all. Mars would potentially still be


00:42:12.560 --> 00:42:15.510
habitable where Venus is when Venus


00:42:15.520 --> 00:42:17.829
isn't. And so that's immediately


00:42:17.839 --> 00:42:19.430
pointing that this story is actually


00:42:19.440 --> 00:42:21.190
significantly more complex.


00:42:21.200 --> 00:42:21.589
>> Yeah.


00:42:21.599 --> 00:42:25.190
>> That you can't just say, let's calculate


00:42:25.200 --> 00:42:26.950
the habitable zone. Let's calculate the


00:42:26.960 --> 00:42:29.109
equilibrium temperature on a planet,


00:42:29.119 --> 00:42:31.750
which is a temperature it would have if


00:42:31.760 --> 00:42:33.510
it didn't have a greenhouse effect that


00:42:33.520 --> 00:42:35.829
it was a certain reflectivity and it was


00:42:35.839 --> 00:42:37.109
in equilibrium with the light coming in


00:42:37.119 --> 00:42:39.030
and the light going out. And if that


00:42:39.040 --> 00:42:40.710
temperature is from about minus20


00:42:40.720 --> 00:42:42.710
upwards, it's probably warm enough for


00:42:42.720 --> 00:42:43.910
water because, well, you'll have a bit


00:42:43.920 --> 00:42:46.069
of an atmosphere. To me, that's never


00:42:46.079 --> 00:42:48.150
been enough. Now, the reason it's really


00:42:48.160 --> 00:42:50.069
important, at least from my perspective,


00:42:50.079 --> 00:42:53.030
is that finding planets is hard. We'll


00:42:53.040 --> 00:42:55.750
talk about that in another episode, but


00:42:55.760 --> 00:42:58.309
once you find the first of something,


00:42:58.319 --> 00:43:00.069
astronomy, history, and probably every


00:43:00.079 --> 00:43:01.349
other form of scientific endeavor,


00:43:01.359 --> 00:43:02.790
history tells us, finding the first of


00:43:02.800 --> 00:43:04.630
something is hard. But once you've got


00:43:04.640 --> 00:43:06.230
one, you quickly find more and more as


00:43:06.240 --> 00:43:08.390
your technology gets better. Finding


00:43:08.400 --> 00:43:10.710
evidence of life on a planet that is


00:43:10.720 --> 00:43:13.829
similar to the Earth is fundamentally at


00:43:13.839 --> 00:43:15.670
least an order of magnitude if not more


00:43:15.680 --> 00:43:18.550
harder than finding that planet was. So


00:43:18.560 --> 00:43:20.069
it'll take time for our technology to


00:43:20.079 --> 00:43:22.390
get good enough to search comfortably


00:43:22.400 --> 00:43:24.790
for life elsewhere. So initially that


00:43:24.800 --> 00:43:26.390
search is going to be very restricted


00:43:26.400 --> 00:43:28.790
because we've got limited resources. So


00:43:28.800 --> 00:43:30.069
you're only going to be able to look at


00:43:30.079 --> 00:43:32.790
a few planets aggressively at first to


00:43:32.800 --> 00:43:34.870
try and tease out any indication of


00:43:34.880 --> 00:43:37.270
life. But you're going to have loads to


00:43:37.280 --> 00:43:38.710
choose from. How should you choose?


00:43:38.720 --> 00:43:40.790
Well, to me, it can't just be the


00:43:40.800 --> 00:43:44.069
habitable zone.


00:43:44.079 --> 00:43:47.670
>> Yeah, that's a valid point. Um, and and


00:43:47.680 --> 00:43:50.069
we've reached a point where we've found


00:43:50.079 --> 00:43:52.630
thousands upon thousands of exoplanets


00:43:52.640 --> 00:43:54.630
and counting. Like, we haven't stopped.


00:43:54.640 --> 00:43:55.990
We're finding them more and more and


00:43:56.000 --> 00:43:58.710
more often of all different shapes of


00:43:58.720 --> 00:44:02.069
sides sizes. Um,


00:44:02.079 --> 00:44:04.309
some rocky planets, they've been harder


00:44:04.319 --> 00:44:06.150
to find cuz they're they're usually much


00:44:06.160 --> 00:44:09.190
smaller and and don't sort of indicate


00:44:09.200 --> 00:44:12.470
themselves like a gas giant does. But


00:44:12.480 --> 00:44:15.109
we're getting better at finding uh rocky


00:44:15.119 --> 00:44:17.910
planets. Um,


00:44:17.920 --> 00:44:20.309
I suppose the big question is given how


00:44:20.319 --> 00:44:23.589
much we are finding, how do you identify


00:44:23.599 --> 00:44:25.670
prime targets for life?


00:44:25.680 --> 00:44:28.069
>> Yeah. And that is what the paper that I


00:44:28.079 --> 00:44:29.829
put together with Barry Jones back in


00:44:29.839 --> 00:44:33.030
2010 was all about. So Barry was a very


00:44:33.040 --> 00:44:34.790
dear friend of mine. He was my boss when


00:44:34.800 --> 00:44:36.870
I moved to the Open University from 2006


00:44:36.880 --> 00:44:38.710
to 2009. I think he knew Fred very well


00:44:38.720 --> 00:44:40.550
as well. So you can always mention to


00:44:40.560 --> 00:44:42.309
Fred that we talked about Barry. I


00:44:42.319 --> 00:44:44.069
started work at the Open University in


00:44:44.079 --> 00:44:45.990
2006 on the day Barry was forced to


00:44:46.000 --> 00:44:47.670
retire by the government because he'd


00:44:47.680 --> 00:44:50.230
hit 67. So he hired me and promptly


00:44:50.240 --> 00:44:53.190
retired but um he kept working anyway as


00:44:53.200 --> 00:44:56.309
ameritus professor. And Barry and I did


00:44:56.319 --> 00:44:57.670
a lot of work on this during my time


00:44:57.680 --> 00:44:59.349
there. Barry unfortunately passed away a


00:44:59.359 --> 00:45:00.790
little bit more than a decade ago. So


00:45:00.800 --> 00:45:03.270
he's fondly remembered. I organized a an


00:45:03.280 --> 00:45:05.109
award in the UK in his memory every


00:45:05.119 --> 00:45:07.589
couple of years. What we did in this


00:45:07.599 --> 00:45:11.829
2010 paper was to essentially have the


00:45:11.839 --> 00:45:13.829
thought process we just outlined. So,


00:45:13.839 --> 00:45:15.990
we're going to have a huge number of


00:45:16.000 --> 00:45:18.230
potential exo earths, planets that could


00:45:18.240 --> 00:45:20.630
potentially be Earthlike that could be


00:45:20.640 --> 00:45:23.109
places to look for life, but we're only


00:45:23.119 --> 00:45:24.630
going to be able to search a handful of


00:45:24.640 --> 00:45:27.030
them initially. So, what should we do to


00:45:27.040 --> 00:45:29.910
select the best target? Now, obviously,


00:45:29.920 --> 00:45:31.990
the closer the planet's hosts are is to


00:45:32.000 --> 00:45:33.270
the solar system, the easier the


00:45:33.280 --> 00:45:35.670
observations will be. That's just a


00:45:35.680 --> 00:45:37.589
fundamental thing of if you're twice as


00:45:37.599 --> 00:45:39.270
far away, we only receive a quarter as


00:45:39.280 --> 00:45:41.270
much light from you. But also, if you're


00:45:41.280 --> 00:45:42.870
twice as far away, the separation


00:45:42.880 --> 00:45:44.390
between the planet and the star on the


00:45:44.400 --> 00:45:47.589
sky will be half as much because the


00:45:47.599 --> 00:45:49.109
angle gets smaller the further away you


00:45:49.119 --> 00:45:51.270
go essentially. And we will want targets


00:45:51.280 --> 00:45:52.710
that are far enough from the star in the


00:45:52.720 --> 00:45:54.069
sky that with future missions like


00:45:54.079 --> 00:45:55.349
potentially the habitable world's


00:45:55.359 --> 00:45:57.510
observatory, we can separate the light


00:45:57.520 --> 00:45:58.870
from the planet from the light from the


00:45:58.880 --> 00:46:01.829
star. So, probably even more important


00:46:01.839 --> 00:46:03.750
than the habitable zone is this


00:46:03.760 --> 00:46:06.790
proximity thing. The planets in the main


00:46:06.800 --> 00:46:08.950
found by the Kepler space telescope


00:46:08.960 --> 00:46:10.230
won't be suitable for this search


00:46:10.240 --> 00:46:12.150
because they're mainly very far from the


00:46:12.160 --> 00:46:14.390
sun and so therefore they'll be very


00:46:14.400 --> 00:46:16.069
hard to study. We want to look locally.


00:46:16.079 --> 00:46:18.309
That's a given,


00:46:18.319 --> 00:46:20.309
but we want to look for places where


00:46:20.319 --> 00:46:22.150
there is the possibility of liquid water


00:46:22.160 --> 00:46:24.390
on the surface because that means that


00:46:24.400 --> 00:46:25.829
the life will be in contact with the


00:46:25.839 --> 00:46:27.190
atmosphere and that might generate a


00:46:27.200 --> 00:46:28.390
signature we can detect in the


00:46:28.400 --> 00:46:29.349
atmosphere.


00:46:29.359 --> 00:46:30.630
>> And that's where the habitable zone


00:46:30.640 --> 00:46:33.109
comes from. But there's actually much


00:46:33.119 --> 00:46:35.109
more to it than that I think. And I'm


00:46:35.119 --> 00:46:36.950
far from able to give an exhaustive list


00:46:36.960 --> 00:46:38.710
because I'm not an expert in all all


00:46:38.720 --> 00:46:41.349
areas of astronomy. But we decided to


00:46:41.359 --> 00:46:44.150
put together a review paper which about


00:46:44.160 --> 00:46:46.870
32 pages long, probably a little bit


00:46:46.880 --> 00:46:48.390
outdated now because science has moved


00:46:48.400 --> 00:46:51.910
forward, but was saying effectively you


00:46:51.920 --> 00:46:54.309
can't just use a habitable zone. We need


00:46:54.319 --> 00:46:56.550
to think about all of the different


00:46:56.560 --> 00:46:58.309
factors that can contribute to make a


00:46:58.319 --> 00:46:59.910
planet more or less suitable for life.


00:46:59.920 --> 00:47:02.069
Now, many of these have been in the past


00:47:02.079 --> 00:47:04.230
suggested as that onoff switch. And I do


00:47:04.240 --> 00:47:06.230
think that they're more sliders like the


00:47:06.240 --> 00:47:07.750
numbers in the Drake equation or sliders


00:47:07.760 --> 00:47:10.230
on a mixing desk. But there are a lot of


00:47:10.240 --> 00:47:11.109
different things that have been


00:47:11.119 --> 00:47:13.270
suggested. And as I dug into the paper,


00:47:13.280 --> 00:47:14.790
there were even more than I thought of.


00:47:14.800 --> 00:47:17.109
You can broadly break them down into


00:47:17.119 --> 00:47:19.589
four areas. The first is galactic


00:47:19.599 --> 00:47:22.790
influences. So the impact of the galaxy


00:47:22.800 --> 00:47:24.710
itself, where you are in the galaxy,


00:47:24.720 --> 00:47:26.390
stuff like that. You've then got stellar


00:47:26.400 --> 00:47:28.790
influences, so the role of the star.


00:47:28.800 --> 00:47:30.230
You've got the planetary system. And


00:47:30.240 --> 00:47:31.910
then you've got the planet itself. So th


00:47:31.920 --> 00:47:34.870
those the kind of four broad areas. The


00:47:34.880 --> 00:47:37.270
galactic influences one is probably the


00:47:37.280 --> 00:47:38.470
least useful and the least well


00:47:38.480 --> 00:47:40.390
constrained. But the idea of the


00:47:40.400 --> 00:47:42.710
galactic influence is tied a bit to a


00:47:42.720 --> 00:47:44.230
theory that's been put forward by a few


00:47:44.240 --> 00:47:45.750
people called the galactic habitable


00:47:45.760 --> 00:47:50.069
zone. It's an idea that ties back to the


00:47:50.079 --> 00:47:51.910
origin of stars and planets and also to


00:47:51.920 --> 00:47:53.510
the dangers that are experienced because


00:47:53.520 --> 00:47:55.910
of your environment. The idea that as


00:47:55.920 --> 00:47:57.670
time goes on, the universe is becoming


00:47:57.680 --> 00:48:00.230
more metalrich. And by that I mean


00:48:00.240 --> 00:48:01.510
enriched in everything other than


00:48:01.520 --> 00:48:03.109
hydrogen and helium because generations


00:48:03.119 --> 00:48:05.510
of stars run their furnaces and turn the


00:48:05.520 --> 00:48:07.109
light elements to the heavy ones and put


00:48:07.119 --> 00:48:09.270
them back into the cosmos. You need a


00:48:09.280 --> 00:48:10.950
certain amount of heavy elements to form


00:48:10.960 --> 00:48:12.710
planets like the Earth and to have the


00:48:12.720 --> 00:48:15.829
carbon, nitrogen, phosphorus for life.


00:48:15.839 --> 00:48:17.670
So as time goes on, the universe getting


00:48:17.680 --> 00:48:19.670
more enriched is a good thing. But


00:48:19.680 --> 00:48:21.750
there's also possibilities that too much


00:48:21.760 --> 00:48:23.349
enrichment will change the chemistry or


00:48:23.359 --> 00:48:25.589
it will make planet formation too easy.


00:48:25.599 --> 00:48:27.750
There's all sorts. So you might have a


00:48:27.760 --> 00:48:30.710
sweet spot from that side of things. Now


00:48:30.720 --> 00:48:32.470
in the middle of the galaxy, star


00:48:32.480 --> 00:48:34.150
formation occurs at a more rapid pace


00:48:34.160 --> 00:48:36.549
and stars live and die quicker. So you


00:48:36.559 --> 00:48:39.990
get faster change in the abundance of


00:48:40.000 --> 00:48:42.150
materials. So you can imagine we have


00:48:42.160 --> 00:48:43.430
this concept in astronomy called


00:48:43.440 --> 00:48:45.990
metallicity which is the amount it's


00:48:46.000 --> 00:48:47.109
usually measured in the amount of


00:48:47.119 --> 00:48:49.349
hydrogen compared to the amount of iron


00:48:49.359 --> 00:48:51.589
in a star and that gives you a number on


00:48:51.599 --> 00:48:53.990
a logarithmic scale and that is a an


00:48:54.000 --> 00:48:56.069
approximation to when the star formed


00:48:56.079 --> 00:48:57.670
and how enriched the world was at the


00:48:57.680 --> 00:48:59.589
time and as time goes on things get more


00:48:59.599 --> 00:49:02.069
and more metalrich within our galaxy


00:49:02.079 --> 00:49:03.510
you'd expect there to be a gradient in


00:49:03.520 --> 00:49:04.950
this. So the things near the middle will


00:49:04.960 --> 00:49:06.870
be much more enriched in heavy elements


00:49:06.880 --> 00:49:08.710
of things near the outer edge and


00:49:08.720 --> 00:49:09.990
there's probably sweet spot in the


00:49:10.000 --> 00:49:12.150
middle that moves outwards over time


00:49:12.160 --> 00:49:13.990
where conditions to form planets like


00:49:14.000 --> 00:49:15.670
the earth and planetary systems like the


00:49:15.680 --> 00:49:18.470
solar system are perfect. So that's part


00:49:18.480 --> 00:49:20.309
of the galactic habitable zone idea. The


00:49:20.319 --> 00:49:22.470
other idea is that if you're too close


00:49:22.480 --> 00:49:25.109
in and the stellar density is too high,


00:49:25.119 --> 00:49:26.790
eventually the stellar density gets so


00:49:26.800 --> 00:49:28.549
high that the likelihood of life being


00:49:28.559 --> 00:49:31.109
exterminated by nearby supernovi or


00:49:31.119 --> 00:49:32.549
planetary systems being stripped and


00:49:32.559 --> 00:49:34.710
disrupted becomes too high. So there's


00:49:34.720 --> 00:49:36.710
always been this idea that location


00:49:36.720 --> 00:49:39.990
within the galaxy is important. The


00:49:40.000 --> 00:49:42.790
challenge to that is twofold. Firstly,


00:49:42.800 --> 00:49:44.470
the proximity argument. We're going to


00:49:44.480 --> 00:49:45.670
have to look at stars that are very


00:49:45.680 --> 00:49:47.910
nearby which are all at the same


00:49:47.920 --> 00:49:48.950
distance from in the middle of the


00:49:48.960 --> 00:49:51.510
galaxy as we are. So where you are in


00:49:51.520 --> 00:49:54.230
the galaxy won't realistically impact


00:49:54.240 --> 00:49:55.430
this search because we're going to be


00:49:55.440 --> 00:49:57.430
looking locally. The other things though


00:49:57.440 --> 00:49:59.190
is that stars have a huge degree of


00:49:59.200 --> 00:50:01.349
mobility. There was a recent story


00:50:01.359 --> 00:50:03.510
talking about finding s solar twins,


00:50:03.520 --> 00:50:05.109
stars that have the same chemistry as


00:50:05.119 --> 00:50:07.030
the sun that may have formed with the


00:50:07.040 --> 00:50:09.990
sun and a suggestion that the sun and


00:50:10.000 --> 00:50:11.589
other stars may have formed as much as


00:50:11.599 --> 00:50:13.270
10,000 light years nearer the middle of


00:50:13.280 --> 00:50:15.349
the galaxy than we are now. Stars are


00:50:15.359 --> 00:50:17.109
getting scattered inwards and outwards.


00:50:17.119 --> 00:50:19.589
So seeing a star here now doesn't imply


00:50:19.599 --> 00:50:21.430
that it's always been here.


00:50:21.440 --> 00:50:21.750
>> Yeah.


00:50:21.760 --> 00:50:24.230
>> So the galactic influences I'm not going


00:50:24.240 --> 00:50:25.910
to go into really any more than that,


00:50:25.920 --> 00:50:27.270
but it's worth knowing that they're


00:50:27.280 --> 00:50:28.950
there. It's worth knowing that it's


00:50:28.960 --> 00:50:30.150
point of discussion and that there is


00:50:30.160 --> 00:50:32.309
good research going on about this. It's


00:50:32.319 --> 00:50:34.069
really interesting area, but it doesn't,


00:50:34.079 --> 00:50:36.069
I think, impact our initial search for


00:50:36.079 --> 00:50:39.510
life because we're going to be searching


00:50:39.520 --> 00:50:41.270
our local area. So, it's a bit like me


00:50:41.280 --> 00:50:42.710
saying I want to search for signs of


00:50:42.720 --> 00:50:44.870
life on Earth. It's a lot easier for me


00:50:44.880 --> 00:50:47.510
to search in King Soap where I live than


00:50:47.520 --> 00:50:50.470
to search in Mumbai or in London, places


00:50:50.480 --> 00:50:52.710
like this. You've got to look locally.


00:50:52.720 --> 00:50:54.470
Now, talking about that, you know, what


00:50:54.480 --> 00:50:55.910
would I expect to find?


00:50:55.920 --> 00:50:58.470
you know the people in King have not all


00:50:58.480 --> 00:50:59.670
but many of them have a similar


00:50:59.680 --> 00:51:01.190
background to me formed in similar ways


00:51:01.200 --> 00:51:03.829
with similar culture all the rest of it


00:51:03.839 --> 00:51:06.790
so this it's a not a great analogy I


00:51:06.800 --> 00:51:08.710
admit but we've got to look locally so


00:51:08.720 --> 00:51:11.589
the galactic influences stuff is


00:51:11.599 --> 00:51:15.349
interesting but I wouldn't say it is a


00:51:15.359 --> 00:51:18.230
big factor but it's worth noting I guess


00:51:18.240 --> 00:51:22.630
>> so that leads us on to um I don't know


00:51:22.640 --> 00:51:25.510
finding the right targets uh And and if


00:51:25.520 --> 00:51:28.470
we do find those targets,


00:51:28.480 --> 00:51:31.670
what what do we do then to look for


00:51:31.680 --> 00:51:33.510
potential life on those targets?


00:51:33.520 --> 00:51:34.950
>> Absolutely. And that's a very hard


00:51:34.960 --> 00:51:36.470
question. Now, in terms of finding the


00:51:36.480 --> 00:51:37.990
right targets, there's a lot that comes


00:51:38.000 --> 00:51:43.190
into it from the star itself. Now, stars


00:51:43.200 --> 00:51:45.589
live very long lives. First question


00:51:45.599 --> 00:51:47.349
then is how old is a star? Now, if we


00:51:47.359 --> 00:51:49.510
look at life on Earth, the oldest


00:51:49.520 --> 00:51:51.109
fossils on Earth that are widely


00:51:51.119 --> 00:51:52.950
accepted are about 3 and a half thousand


00:51:52.960 --> 00:51:54.790
million years old are in the Pilra,


00:51:54.800 --> 00:51:56.630
which is about a billion years after the


00:51:56.640 --> 00:51:58.470
Earth formed. There are some that are


00:51:58.480 --> 00:52:00.150
older that are still controversial,


00:52:00.160 --> 00:52:01.750
possibly as old as 4 billion years. But


00:52:01.760 --> 00:52:04.150
if we take the 3 1/2 billion years as a


00:52:04.160 --> 00:52:06.069
threshold and we do what we're doing


00:52:06.079 --> 00:52:07.510
with the liquid water thing and we say


00:52:07.520 --> 00:52:09.270
we expect life to follow a similar path


00:52:09.280 --> 00:52:11.750
to us, the fact that it took a billion


00:52:11.760 --> 00:52:13.270
years for life to get established enough


00:52:13.280 --> 00:52:15.589
to leave fossils we could find possibly


00:52:15.599 --> 00:52:16.950
means that it might have taken a similar


00:52:16.960 --> 00:52:18.470
length of time for that life to modify


00:52:18.480 --> 00:52:19.990
its environment enough to be detectable


00:52:20.000 --> 00:52:21.829
from elsewhere. So we can put an


00:52:21.839 --> 00:52:24.230
arbitrary kind of timer here saying that


00:52:24.240 --> 00:52:26.870
any planetary system younger than say a


00:52:26.880 --> 00:52:29.430
billion years may have planets that are


00:52:29.440 --> 00:52:30.870
suitable for life but that life might


00:52:30.880 --> 00:52:32.470
have not had enough time to get


00:52:32.480 --> 00:52:35.910
established yet. So that might


00:52:35.920 --> 00:52:37.990
immediately say that's not as good a


00:52:38.000 --> 00:52:39.349
place to look as a star that is more


00:52:39.359 --> 00:52:41.349
like the age of the sun where life's had


00:52:41.359 --> 00:52:43.589
four billion years to get going. Now


00:52:43.599 --> 00:52:46.790
tied to that is the fact that the lives


00:52:46.800 --> 00:52:48.390
of stars are very dependent on their


00:52:48.400 --> 00:52:50.549
mass. So the more massive a star is, the


00:52:50.559 --> 00:52:52.069
brighter it shines, but the shorter its


00:52:52.079 --> 00:52:55.349
life is. And at a very rough level, this


00:52:55.359 --> 00:52:56.710
number varies a little bit depending on


00:52:56.720 --> 00:52:58.870
the mass of the star. But typically the


00:52:58.880 --> 00:53:00.790
luminosity of a star is proportional to


00:53:00.800 --> 00:53:03.030
its mass to the power four. So if you've


00:53:03.040 --> 00:53:04.549
got a star that is 10 times the mass of


00:53:04.559 --> 00:53:06.710
the sun, it will be roughly 10,000 times


00:53:06.720 --> 00:53:09.270
brighter than the sun. But these stars


00:53:09.280 --> 00:53:10.710
are burning their own material. They're


00:53:10.720 --> 00:53:12.150
turning hydrogen to helium and they're


00:53:12.160 --> 00:53:14.230
made of hydrogen. So a star that is 10


00:53:14.240 --> 00:53:16.309
times the mass of the sun will only have


00:53:16.319 --> 00:53:18.710
10 times as much fuel as a sun. But it's


00:53:18.720 --> 00:53:21.109
burning that fuel 10,000 times quicker,


00:53:21.119 --> 00:53:23.190
which means it'll run out a lot quicker.


00:53:23.200 --> 00:53:24.710
And what that means is that the more


00:53:24.720 --> 00:53:26.950
massive a star is, the longer, the


00:53:26.960 --> 00:53:28.870
shorter its life will be. And the less


00:53:28.880 --> 00:53:30.309
massive a star is, the longer its life


00:53:30.319 --> 00:53:33.349
will be. That means that beyond a


00:53:33.359 --> 00:53:35.829
certain stellar mass, the star will die


00:53:35.839 --> 00:53:38.230
before that billionyear cutoff. So we


00:53:38.240 --> 00:53:39.670
can probably rule out the most massive


00:53:39.680 --> 00:53:41.670
stars. They'll just live fast, die


00:53:41.680 --> 00:53:43.430
young, and it's unlikely that life will


00:53:43.440 --> 00:53:45.750
get well enough established. On the flip


00:53:45.760 --> 00:53:47.349
side, the dim little red dwarfs will


00:53:47.359 --> 00:53:48.790
just go forever. You know, Proxima


00:53:48.800 --> 00:53:50.390
Centtory will still be traveling along


00:53:50.400 --> 00:53:52.069
in a trillion years when we're a distant


00:53:52.079 --> 00:53:54.150
memory. So, they might be a good place


00:53:54.160 --> 00:53:56.470
to look. The challenge there though is


00:53:56.480 --> 00:53:59.349
that those stars are quite active quite


00:53:59.359 --> 00:54:02.069
often. And to be in the habitable zone


00:54:02.079 --> 00:54:03.270
around them, you've got to be very close


00:54:03.280 --> 00:54:04.710
in because they're called little embers.


00:54:04.720 --> 00:54:06.549
You've got to snuggle up to the fire. So


00:54:06.559 --> 00:54:07.910
there's a lot of discussion about the


00:54:07.920 --> 00:54:10.390
fact that M dwarf planets planets around


00:54:10.400 --> 00:54:12.309
these coolest smallest stars are


00:54:12.319 --> 00:54:13.750
probably not ideal places to look for


00:54:13.760 --> 00:54:15.990
knife initially. Few reasons. One is


00:54:16.000 --> 00:54:17.990
that activity and a lot of discussions


00:54:18.000 --> 00:54:19.510
that the activity of red dwarfs when


00:54:19.520 --> 00:54:20.870
they're young could scour a planet's


00:54:20.880 --> 00:54:22.630
atmosphere away and that seems to have


00:54:22.640 --> 00:54:24.150
possibly been backed up with a trappist


00:54:24.160 --> 00:54:26.950
one planets that all seem to be airless


00:54:26.960 --> 00:54:29.990
worlds. The other is that those planets,


00:54:30.000 --> 00:54:31.910
if they are close enough in to be warm


00:54:31.920 --> 00:54:33.270
enough for liquid water on the surface,


00:54:33.280 --> 00:54:35.270
would have to be tidily locked like the


00:54:35.280 --> 00:54:37.109
moon is to the earth, which means


00:54:37.119 --> 00:54:38.390
they'll keep one face permanently


00:54:38.400 --> 00:54:39.750
pointed towards the star and the other


00:54:39.760 --> 00:54:42.309
permanently away, which may make it


00:54:42.319 --> 00:54:43.910
harder to look for light on them. It


00:54:43.920 --> 00:54:45.670
might be the case that any life would be


00:54:45.680 --> 00:54:47.670
on the sunwood side, and that's kind of


00:54:47.680 --> 00:54:49.030
hard to observe because when that side


00:54:49.040 --> 00:54:51.349
is best presented to us, it's near the


00:54:51.359 --> 00:54:54.069
star. So, that's challenging. Another


00:54:54.079 --> 00:54:56.069
thing that factors into it ties into


00:54:56.079 --> 00:54:57.829
something called the faint early sun


00:54:57.839 --> 00:55:01.510
paradox on Earth. The


00:55:01.520 --> 00:55:03.750
lives of stars, they shine brightly.


00:55:03.760 --> 00:55:05.349
Their brightness is measured compared to


00:55:05.359 --> 00:55:06.950
their mass, but their brightness


00:55:06.960 --> 00:55:09.030
increases with time. Stars get more


00:55:09.040 --> 00:55:10.549
luminous as they age a little bit. And


00:55:10.559 --> 00:55:13.349
it's a slow process. But with the sun,


00:55:13.359 --> 00:55:16.790
we think the sun was 30% dimmer when it


00:55:16.800 --> 00:55:19.510
was born to how it is now. So that means


00:55:19.520 --> 00:55:21.510
the earth at the time got 30% less


00:55:21.520 --> 00:55:24.150
energy which would have put it with its


00:55:24.160 --> 00:55:26.150
current atmosphere


00:55:26.160 --> 00:55:29.430
too cold to support life. Um that was


00:55:29.440 --> 00:55:30.790
offset by the fact we had a very


00:55:30.800 --> 00:55:32.069
different atmosphere then and a


00:55:32.079 --> 00:55:33.589
significant


00:55:33.599 --> 00:55:35.829
greenhouse effect which was lessened due


00:55:35.839 --> 00:55:38.309
to the influence of life stripping out


00:55:38.319 --> 00:55:39.990
carbon dioxide particularly from the


00:55:40.000 --> 00:55:41.829
atmosphere and keeping us mostly there


00:55:41.839 --> 00:55:44.390
and thereabouts. But what that means is


00:55:44.400 --> 00:55:47.030
that if we find a planet now and that


00:55:47.040 --> 00:55:48.309
planet is near the outer edge of the


00:55:48.319 --> 00:55:50.150
habitable zone, everybody will go,


00:55:50.160 --> 00:55:51.430
"Well, it's in the habitable zone.


00:55:51.440 --> 00:55:53.750
That's great." Whereas my question would


00:55:53.760 --> 00:55:55.270
then be, "But how long has it been in


00:55:55.280 --> 00:55:57.190
the habitable zone?" Because when the


00:55:57.200 --> 00:55:59.349
star was younger, it was a little bit


00:55:59.359 --> 00:56:01.190
dimmer. The habitable zone would have


00:56:01.200 --> 00:56:02.549
been closer in, and that planet might


00:56:02.559 --> 00:56:04.630
well have been outside it. So, I don't


00:56:04.640 --> 00:56:05.829
necessarily think that that 1


00:56:05.839 --> 00:56:08.390
billionyear clock would start until the


00:56:08.400 --> 00:56:09.829
planet was in the habitable zone. So


00:56:09.839 --> 00:56:11.349
we'll probably then be able to rule some


00:56:11.359 --> 00:56:14.950
planets out on the basis of the fact


00:56:14.960 --> 00:56:17.190
that they could be in the habitable zone


00:56:17.200 --> 00:56:18.630
now, but they haven't been full long


00:56:18.640 --> 00:56:19.430
enough.


00:56:19.440 --> 00:56:19.589
>> Yeah.


00:56:19.599 --> 00:56:21.589
>> So the star has all these effects. Never


00:56:21.599 --> 00:56:23.829
mind the fact that astronomers often


00:56:23.839 --> 00:56:25.349
joke that three out of every two stars


00:56:25.359 --> 00:56:28.150
are in a multiple star system. um


00:56:28.160 --> 00:56:30.950
multiple stars are very very common and


00:56:30.960 --> 00:56:32.870
that adds a whole extra level of


00:56:32.880 --> 00:56:35.670
complexity both to the understanding of


00:56:35.680 --> 00:56:37.430
the lives of the planets in those stars


00:56:37.440 --> 00:56:39.829
but also in our ability to study them


00:56:39.839 --> 00:56:41.349
because you've got more than one stars


00:56:41.359 --> 00:56:43.670
like to factor in all close together.


00:56:43.680 --> 00:56:45.349
It's much nastier and much more


00:56:45.359 --> 00:56:47.510
complicated. So there's a lot of ways


00:56:47.520 --> 00:56:49.349
that the stars can factor in and I think


00:56:49.359 --> 00:56:52.309
that's only a very very broad brush


00:56:52.319 --> 00:56:54.630
strokes for view. But you can see how


00:56:54.640 --> 00:56:56.309
what I'm thinking is you can bring in


00:56:56.319 --> 00:56:59.190
all these different ideas and have them


00:56:59.200 --> 00:57:01.510
as a slider. This kind of star could


00:57:01.520 --> 00:57:02.950
have planets around it with life, but


00:57:02.960 --> 00:57:05.510
it's not as good a target as this one.


00:57:05.520 --> 00:57:06.710
Now, everybody could build their own


00:57:06.720 --> 00:57:08.150
algorithm out of this, but I'd like to


00:57:08.160 --> 00:57:09.510
think that when we're trying to pick the


00:57:09.520 --> 00:57:12.390
target, you take into account the star


00:57:12.400 --> 00:57:14.069
that it's going around, how active it


00:57:14.079 --> 00:57:16.630
is. Is it a single star? Is it old


00:57:16.640 --> 00:57:19.750
enough? All these kind of factors. And


00:57:19.760 --> 00:57:21.589
then you can start looking at the


00:57:21.599 --> 00:57:23.270
planetary system that it's in. And


00:57:23.280 --> 00:57:24.950
there's a lot to talk about there, I


00:57:24.960 --> 00:57:25.670
think.


00:57:25.680 --> 00:57:30.470
>> Yes, absolutely. Uh and in our next um


00:57:30.480 --> 00:57:34.150
uh special um between Q&A episodes, we


00:57:34.160 --> 00:57:37.910
will um look more into um the the planet


00:57:37.920 --> 00:57:39.829
side of things. I I guess just to


00:57:39.839 --> 00:57:43.349
conclude um I'll throw one at you. Um


00:57:43.359 --> 00:57:45.190
and and this answer is always different


00:57:45.200 --> 00:57:47.750
depending on who you ask, but uh what do


00:57:47.760 --> 00:57:50.549
you think the odds are that we will find


00:57:50.559 --> 00:57:53.109
some form of life?


00:57:53.119 --> 00:57:56.309
>> Um I I'm an optimist. I think the answer


00:57:56.319 --> 00:57:58.230
to it will be yes, we will find some


00:57:58.240 --> 00:58:00.069
sort of life. I think the harder


00:58:00.079 --> 00:58:04.549
question is when. Now, if we find life


00:58:04.559 --> 00:58:06.150
in a million years time when we're not


00:58:06.160 --> 00:58:07.430
even human anymore, but we've hung


00:58:07.440 --> 00:58:09.510
around, we've managed to survive. That's


00:58:09.520 --> 00:58:10.950
not very edifying for me and you cuz


00:58:10.960 --> 00:58:13.030
it's a long time to wait. But as I said


00:58:13.040 --> 00:58:14.230
earlier on, I don't think it's a


00:58:14.240 --> 00:58:15.990
question of if, it's a question of when.


00:58:16.000 --> 00:58:19.670
Because I find it vanishingly improbable


00:58:19.680 --> 00:58:23.349
for us to be the only system with life.


00:58:23.359 --> 00:58:24.630
>> And it's a numbers game for me. You


00:58:24.640 --> 00:58:26.309
know, we've got a galaxy with between


00:58:26.319 --> 00:58:30.549
200 and 400,000 million stars. There are


00:58:30.559 --> 00:58:33.190
more galaxies in the visible universe


00:58:33.200 --> 00:58:35.589
certainly than there are planets in our


00:58:35.599 --> 00:58:37.670
galaxy. probably more than there are


00:58:37.680 --> 00:58:39.829
grains of sand in our galaxy. All of


00:58:39.839 --> 00:58:41.109
them with hundreds of thousands of


00:58:41.119 --> 00:58:43.430
millions of stars.


00:58:43.440 --> 00:58:45.349
To say that out of if you run the


00:58:45.359 --> 00:58:47.670
numbers you get sectillions,


00:58:47.680 --> 00:58:50.309
septillions, even octillions


00:58:50.319 --> 00:58:54.230
bonkersly full-on numbers of planets out


00:58:54.240 --> 00:58:56.309
there that were the only place that got


00:58:56.319 --> 00:58:58.309
life. That tells you that life is


00:58:58.319 --> 00:58:59.750
effectively impossible and we're a


00:58:59.760 --> 00:59:00.950
fluke.


00:59:00.960 --> 00:59:04.230
>> Now, that could be the case. If that's


00:59:04.240 --> 00:59:05.589
the case, what we've got here on Earth


00:59:05.599 --> 00:59:07.910
becomes even more precious and there is


00:59:07.920 --> 00:59:10.950
an even greater incentive for us to keep


00:59:10.960 --> 00:59:13.190
an eye on what we're doing so that Earth


00:59:13.200 --> 00:59:14.789
is still capable of hosting life in the


00:59:14.799 --> 00:59:17.589
future. But I think in reality, life


00:59:17.599 --> 00:59:19.030
will actually be more common than that.


00:59:19.040 --> 00:59:20.390
And you don't need to be much more


00:59:20.400 --> 00:59:22.870
common than that for life to be abundant


00:59:22.880 --> 00:59:25.750
in the galaxy. Let's imagine that life


00:59:25.760 --> 00:59:29.589
is found on one planet in 1 billion.


00:59:29.599 --> 00:59:31.109
That's billion with a B. So one in a


00:59:31.119 --> 00:59:33.510
thousand million. Now, we're finding


00:59:33.520 --> 00:59:35.670
that on average all stars have planets,


00:59:35.680 --> 00:59:37.270
probably have a number of planets. So,


00:59:37.280 --> 00:59:39.030
if we say roughly there are 10 planets


00:59:39.040 --> 00:59:41.030
per star, there will be four trillion


00:59:41.040 --> 00:59:43.750
planets in our galaxy. If one in a


00:59:43.760 --> 00:59:46.710
billion had life on it, that would mean


00:59:46.720 --> 00:59:49.030
there were 4,000 inhabited planets in


00:59:49.040 --> 00:59:50.870
our galaxy.


00:59:50.880 --> 00:59:52.549
>> Not a big number. The nearest one would


00:59:52.559 --> 00:59:54.069
be so far away in that case, we wouldn't


00:59:54.079 --> 00:59:56.710
find life for a long time. But life


00:59:56.720 --> 00:59:58.710
could be common and we still wouldn't


00:59:58.720 --> 01:00:00.390
find it. The more you increase that


01:00:00.400 --> 01:00:03.349
likelihood of life, the nearer the


01:00:03.359 --> 01:00:05.109
nearest examples will be and the sooner


01:00:05.119 --> 01:00:06.390
we'll find it. And that's why I think


01:00:06.400 --> 01:00:08.950
proximity will tell us a lot about the


01:00:08.960 --> 01:00:12.470
probability of life in that if we find


01:00:12.480 --> 01:00:15.510
life, the next step is to figure out we


01:00:15.520 --> 01:00:17.109
are not alone. We know we're not alone.


01:00:17.119 --> 01:00:19.670
How common is life? Now the other thing


01:00:19.680 --> 01:00:21.270
I think factors into it I think is a


01:00:21.280 --> 01:00:23.670
lovely kind of sci-fi thing to discuss


01:00:23.680 --> 01:00:24.870
all the way through you mentioned early


01:00:24.880 --> 01:00:27.430
on carbon based life and technologically


01:00:27.440 --> 01:00:30.230
advanced life and we drifted away the


01:00:30.240 --> 01:00:33.030
one place where I think that life that


01:00:33.040 --> 01:00:34.870
is different to us is something we could


01:00:34.880 --> 01:00:38.789
possibly find is siliconbased life now


01:00:38.799 --> 01:00:41.510
the reason for that is not from the


01:00:41.520 --> 01:00:45.510
point of view of um silicon people who


01:00:45.520 --> 01:00:48.069
have evolved in the way we have done I'm


01:00:48.079 --> 01:00:50.150
thinking more kind of second generation


01:00:50.160 --> 01:00:52.390
life. Now, our exploration of the solar


01:00:52.400 --> 01:00:54.789
system is done by our robot envoys and


01:00:54.799 --> 01:00:56.549
we're sending them near enough to home


01:00:56.559 --> 01:00:58.710
that we can tell them what to do.


01:00:58.720 --> 01:01:01.349
>> But we are developing to certain


01:01:01.359 --> 01:01:02.870
controversy at the current time. We're


01:01:02.880 --> 01:01:04.630
developing a greater and greater ability


01:01:04.640 --> 01:01:06.309
to develop things that can make


01:01:06.319 --> 01:01:07.910
decisions for themselves without human


01:01:07.920 --> 01:01:11.030
input. Things like AI and other systems.


01:01:11.040 --> 01:01:12.710
And if we get to the point where we want


01:01:12.720 --> 01:01:16.470
to explore around other stars, we'll


01:01:16.480 --> 01:01:18.069
need to develop spacecraft that have


01:01:18.079 --> 01:01:19.510
enough autonomy to make their own


01:01:19.520 --> 01:01:22.069
decisions. You go back to the idea, and


01:01:22.079 --> 01:01:23.190
I don't know what's happened to it in


01:01:23.200 --> 01:01:24.470
recent years, but the idea of project


01:01:24.480 --> 01:01:25.829
star where they made a little


01:01:25.839 --> 01:01:27.670
spacecraft, shot them off with laser,


01:01:27.680 --> 01:01:29.670
then they got to Proxima Centuri in 25


01:01:29.680 --> 01:01:31.829
years traveling at a fifth of the speed


01:01:31.839 --> 01:01:35.109
of light. You do that, they get to


01:01:35.119 --> 01:01:36.630
Proxima Centuri. If they've got to ask


01:01:36.640 --> 01:01:38.710
us what to do, they send a signal to us.


01:01:38.720 --> 01:01:40.710
takes 4 and a bit years to get here.


01:01:40.720 --> 01:01:42.230
Takes five years to get back and by the


01:01:42.240 --> 01:01:43.510
time it reaches them, they're a light


01:01:43.520 --> 01:01:44.789
year beyond the system. It's that well


01:01:44.799 --> 01:01:46.789
too late. So, we have to give them a


01:01:46.799 --> 01:01:48.549
certain level of autonomy. And the more


01:01:48.559 --> 01:01:49.910
complex their mission is going to be,


01:01:49.920 --> 01:01:52.390
the more autonomous it have to be. Which


01:01:52.400 --> 01:01:54.630
leads to the very science fiction idea


01:01:54.640 --> 01:01:57.190
that when we move out beyond the solar


01:01:57.200 --> 01:01:58.870
system, if we move out beyond the solar


01:01:58.880 --> 01:02:02.549
system, we will be preceded by a wave of


01:02:02.559 --> 01:02:06.150
life that is not us. That is our life


01:02:06.160 --> 01:02:08.230
that has a creator. that creator is


01:02:08.240 --> 01:02:10.470
humanity that is silicant based life


01:02:10.480 --> 01:02:11.990
that we send out whether they're


01:02:12.000 --> 01:02:14.390
vonoyman machines whether they are


01:02:14.400 --> 01:02:16.309
incredibly advanced AI machines without


01:02:16.319 --> 01:02:19.109
the capacity to reproduce themselves we


01:02:19.119 --> 01:02:22.710
will send out artificially


01:02:22.720 --> 01:02:25.589
built silicon life forms and again


01:02:25.599 --> 01:02:28.390
there's a a lovely fairly low stakes


01:02:28.400 --> 01:02:31.190
sci-fi series called the Bobbyverse


01:02:31.200 --> 01:02:33.349
um which follows that kind of idea in


01:02:33.359 --> 01:02:36.710
terms of future earth well guy in the


01:02:36.720 --> 01:02:38.789
current day dies but has in invested in


01:02:38.799 --> 01:02:41.430
cryogenics and his head is frozen and he


01:02:41.440 --> 01:02:43.750
wakes up and he's essentially put into a


01:02:43.760 --> 01:02:46.390
van machine and shot out into the stars


01:02:46.400 --> 01:02:47.990
and that that's a really interesting one


01:02:48.000 --> 01:02:49.589
because it's silicon based life that is


01:02:49.599 --> 01:02:51.349
also human. I mean figure that one out


01:02:51.359 --> 01:02:53.030
but it's good fun


01:02:53.040 --> 01:02:54.950
>> following again that very dangerous


01:02:54.960 --> 01:02:57.190
assumption that other life would follow


01:02:57.200 --> 01:02:58.870
the same pathway we follow and it seems


01:02:58.880 --> 01:03:00.549
like we are going down this AI and


01:03:00.559 --> 01:03:02.789
increasing complexity and increasing


01:03:02.799 --> 01:03:05.510
autonomy route. You then argue that


01:03:05.520 --> 01:03:07.990
other species sending out craft into the


01:03:08.000 --> 01:03:11.349
galaxy would send out autonomous


01:03:11.359 --> 01:03:14.710
intelligent silicon machines before they


01:03:14.720 --> 01:03:17.510
send themselves out. And therefore, you


01:03:17.520 --> 01:03:18.870
know, I'd think we're more likely if


01:03:18.880 --> 01:03:20.710
we're ever to bump into aliens to run


01:03:20.720 --> 01:03:22.390
into one of these probes or one of these


01:03:22.400 --> 01:03:24.069
machines rather than the aliens


01:03:24.079 --> 01:03:25.510
themselves. So I think there is a very


01:03:25.520 --> 01:03:27.589
real chance that if we find intelligent


01:03:27.599 --> 01:03:29.829
advanced life it could be siliconbased


01:03:29.839 --> 01:03:31.750
rather than carbon based but it's


01:03:31.760 --> 01:03:33.750
siliconbased life that was created by


01:03:33.760 --> 01:03:37.109
carbon based life which I mean leads to


01:03:37.119 --> 01:03:38.309
really interesting questions about


01:03:38.319 --> 01:03:40.069
philosophy and religion and all those


01:03:40.079 --> 01:03:42.150
kind of things which are not my forte


01:03:42.160 --> 01:03:44.069
but you know it does ask in interesting


01:03:44.079 --> 01:03:46.470
questions about origin and creation when


01:03:46.480 --> 01:03:47.829
you think about it from the context of


01:03:47.839 --> 01:03:49.190
that which is one of the things that's


01:03:49.200 --> 01:03:51.190
driven like I say a lot of wonderful and


01:03:51.200 --> 01:03:52.870
wonderfully entertaining sci-fi over the


01:03:52.880 --> 01:03:55.829
years. Yeah. Yeah. Look, as you said


01:03:55.839 --> 01:03:57.109
earlier, we could we could talk about


01:03:57.119 --> 01:04:01.349
this for a week, but we can't. Um, but


01:04:01.359 --> 01:04:03.670
uh I do uh want to direct people to your


01:04:03.680 --> 01:04:06.230
paper if uh people are interested in


01:04:06.240 --> 01:04:10.390
reading your paper from 2010. Uh it's uh


01:04:10.400 --> 01:04:12.950
called determining habitability, which


01:04:12.960 --> 01:04:15.990
exo earths should we search for life?


01:04:16.000 --> 01:04:18.309
And you can find it on the archive


01:04:18.319 --> 01:04:20.150
website. Is that right, Johnny?


01:04:20.160 --> 01:04:21.430
>> Yeah. So that was published in the


01:04:21.440 --> 01:04:23.190
international journal of astrobiology in


01:04:23.200 --> 01:04:24.710
2010. So the ones who want the kind of


01:04:24.720 --> 01:04:26.390
scientific reference it's international


01:04:26.400 --> 01:04:29.349
journal of astrobiology volume 9 page


01:04:29.359 --> 01:04:32.710
273 onwards. But um if you find it on


01:04:32.720 --> 01:04:34.870
NASA ads it'll give you the archive link


01:04:34.880 --> 01:04:37.190
which is the preprint version which


01:04:37.200 --> 01:04:39.670
basically means it's in my formatting


01:04:39.680 --> 01:04:41.589
rather than journal formatting. And this


01:04:41.599 --> 01:04:44.390
is it's actually a handier aside that


01:04:44.400 --> 01:04:47.430
I'm sure has been mentioned before. The


01:04:47.440 --> 01:04:51.270
way that a lot of science works has led


01:04:51.280 --> 01:04:53.109
to the creation of the most profitable


01:04:53.119 --> 01:04:57.109
and um and problematic um companies in


01:04:57.119 --> 01:04:58.230
the world which are the publishing


01:04:58.240 --> 01:05:00.390
companies. And so the way a scientist


01:05:00.400 --> 01:05:02.470
works is we do all this work da da da da


01:05:02.480 --> 01:05:04.470
hooray hoay huray. We then write a paper


01:05:04.480 --> 01:05:06.309
to tell the world about it. We send that


01:05:06.319 --> 01:05:08.549
off to a journal who gets another


01:05:08.559 --> 01:05:10.390
scientist to volunteer their time unpaid


01:05:10.400 --> 01:05:12.150
for free to referee it.


01:05:12.160 --> 01:05:13.029
>> Y


01:05:13.039 --> 01:05:15.190
>> then they charge typically the scientist


01:05:15.200 --> 01:05:16.630
who's written that paper money to


01:05:16.640 --> 01:05:18.710
publish that paper for them and then


01:05:18.720 --> 01:05:20.150
charge everybody for the privilege of


01:05:20.160 --> 01:05:22.789
reading it. So if I want the journal if


01:05:22.799 --> 01:05:24.150
I want to read the journal versions of


01:05:24.160 --> 01:05:26.789
my papers fortunately universities have


01:05:26.799 --> 01:05:28.630
paid access to a lot of journals but I'm


01:05:28.640 --> 01:05:31.349
fundamentally paying to read my own work


01:05:31.359 --> 01:05:35.589
and this is not ideal. I think partly


01:05:35.599 --> 01:05:36.789
because as a scientist, you know, I'm


01:05:36.799 --> 01:05:38.870
paid by taxpayers money. People are


01:05:38.880 --> 01:05:41.589
paying me to do this work. To me, it is


01:05:41.599 --> 01:05:42.870
really important that they know what


01:05:42.880 --> 01:05:44.150
we're doing. They know what they're


01:05:44.160 --> 01:05:45.990
getting for their money. And part of


01:05:46.000 --> 01:05:47.589
that is be a science communicator. And I


01:05:47.599 --> 01:05:49.109
encourage any scientists or budding


01:05:49.119 --> 01:05:51.029
scientists, don't just focus on the


01:05:51.039 --> 01:05:52.630
science. Focus on communication as well.


01:05:52.640 --> 01:05:53.829
Because if you do science, but can't


01:05:53.839 --> 01:05:55.190
communicate it, no one will know what


01:05:55.200 --> 01:05:58.470
you've done. But to get around that,


01:05:58.480 --> 01:06:00.950
what we do in astronomy and what many


01:06:00.960 --> 01:06:03.990
disciplines do is that we put preprints


01:06:04.000 --> 01:06:06.789
up on a publicly accessible free place.


01:06:06.799 --> 01:06:08.470
And it's in astronomy, it's just


01:06:08.480 --> 01:06:10.630
accepted that with very rare exceptions,


01:06:10.640 --> 01:06:12.710
journals will let you do this. So when


01:06:12.720 --> 01:06:15.349
we get our paper and we've written it,


01:06:15.359 --> 01:06:17.349
some disciplines in astronomy will put


01:06:17.359 --> 01:06:18.870
the paper up on the archive when it's


01:06:18.880 --> 01:06:21.270
submitted. Some will wait until it's


01:06:21.280 --> 01:06:22.470
accepted by the journal, when it's


01:06:22.480 --> 01:06:24.150
refereed. I've always waited till


01:06:24.160 --> 01:06:25.750
acceptance, but occasionally if you've


01:06:25.760 --> 01:06:27.109
made a big discovery, you want to stop


01:06:27.119 --> 01:06:29.190
somebody scooping you. You put it up at


01:06:29.200 --> 01:06:31.029
submission. There's a growing effort by


01:06:31.039 --> 01:06:32.630
scientists to put it up at submission to


01:06:32.640 --> 01:06:34.230
actively solicit feedback from the


01:06:34.240 --> 01:06:35.750
community to improve the work, which is


01:06:35.760 --> 01:06:38.789
good. But those papers go up on archive,


01:06:38.799 --> 01:06:40.789
a rxiv.


01:06:40.799 --> 01:06:41.109
>> Yeah.


01:06:41.119 --> 01:06:44.309
>> Um, be very careful. There is another


01:06:44.319 --> 01:06:46.150
platform out there where the letters in


01:06:46.160 --> 01:06:48.630
archive are shifted around which is


01:06:48.640 --> 01:06:51.349
where a community of people who espouse


01:06:51.359 --> 01:06:52.789
ideas that are not scientifically


01:06:52.799 --> 01:06:55.349
verifiable will put their work and


01:06:55.359 --> 01:06:56.789
publish their own little papers. It's a


01:06:56.799 --> 01:06:59.190
different thing but archive is a


01:06:59.200 --> 01:07:01.910
repository of freeto view things. So if


01:07:01.920 --> 01:07:04.710
you are searching for papers NASA's ads


01:07:04.720 --> 01:07:06.870
system is wonderful. When you click on a


01:07:06.880 --> 01:07:09.190
given paper in there, most of them, but


01:07:09.200 --> 01:07:10.710
not all of them, will have a line that


01:07:10.720 --> 01:07:12.950
says journal version or ads version, but


01:07:12.960 --> 01:07:14.069
there'll also be a line that says


01:07:14.079 --> 01:07:15.829
preprint. And if you click on the


01:07:15.839 --> 01:07:17.349
pre-print links, it will take you to the


01:07:17.359 --> 01:07:19.510
archive and allow you to read the paper


01:07:19.520 --> 01:07:21.750
for free. Just to be aware that that is


01:07:21.760 --> 01:07:24.549
a version some of the time before


01:07:24.559 --> 01:07:25.990
refereeing, most of the time after


01:07:26.000 --> 01:07:27.750
refereeing, but before publishing and


01:07:27.760 --> 01:07:29.990
edits effectively. So, the link you've


01:07:30.000 --> 01:07:32.150
got to that is the pre-print version of


01:07:32.160 --> 01:07:34.309
that paper. The other caution I give to


01:07:34.319 --> 01:07:36.789
people is that it is 16 years old. So


01:07:36.799 --> 01:07:38.870
all of the areas I talk about in it have


01:07:38.880 --> 01:07:41.109
moved on. We've learned more. We can


01:07:41.119 --> 01:07:42.630
talk a bit more about it next time as


01:07:42.640 --> 01:07:44.789
well. But always when you read things be


01:07:44.799 --> 01:07:47.029
conscious of the fact that science is


01:07:47.039 --> 01:07:49.029
fluid. Science changes. Our knowledge


01:07:49.039 --> 01:07:50.950
changes. I see just in the news


01:07:50.960 --> 01:07:54.630
recently, Jayen Isaac Isacson, who's I


01:07:54.640 --> 01:07:56.069
think the head guy at NASA at the


01:07:56.079 --> 01:07:57.510
minute, who's a wealthy


01:07:57.520 --> 01:08:00.230
multi-billionaire type guy, um is


01:08:00.240 --> 01:08:01.750
arguing that the US is wanting to


01:08:01.760 --> 01:08:03.750
strongly build a scientific case why


01:08:03.760 --> 01:08:05.349
Pluto should be restored as a planet


01:08:05.359 --> 01:08:07.349
because fundamentally we discovered it


01:08:07.359 --> 01:08:09.109
so it should still be a planet and Clyde


01:08:09.119 --> 01:08:12.789
Tombbo would be turning in his grave.


01:08:12.799 --> 01:08:15.990
That is what it is. But it's um it is


01:08:16.000 --> 01:08:18.870
important to keep in mind that science


01:08:18.880 --> 01:08:21.030
is fluid. It moves. Whereas once


01:08:21.040 --> 01:08:23.669
something is published that's static.


01:08:23.679 --> 01:08:26.070
>> It's a window on our knowledge at a time


01:08:26.080 --> 01:08:28.950
rather than necessarily the modern


01:08:28.960 --> 01:08:30.470
version. If I were to rewrite that paper


01:08:30.480 --> 01:08:33.030
now there'd be advances.


01:08:33.040 --> 01:08:36.870
>> Of course. Absolutely. But um yes um I


01:08:36.880 --> 01:08:38.149
think we're trying to arrange to put the


01:08:38.159 --> 01:08:39.910
link on the show notes. I'll just have


01:08:39.920 --> 01:08:42.550
to remind Hugh about that. We might wrap


01:08:42.560 --> 01:08:44.390
it up there. Jonty. fascinating topic


01:08:44.400 --> 01:08:46.470
and uh it's one we get a heck of a lot


01:08:46.480 --> 01:08:48.709
of questions about. So, um yeah,


01:08:48.719 --> 01:08:50.390
hopefully there's a bit of information


01:08:50.400 --> 01:08:53.349
in there to uh keep people's minds


01:08:53.359 --> 01:08:55.990
worring. Johnny, thanks very much. We


01:08:56.000 --> 01:08:57.990
will uh see you again real soon. It's an


01:08:58.000 --> 01:08:59.189
absolute pleasure. Thank you for having


01:08:59.199 --> 01:09:00.070
me.


01:09:00.080 --> 01:09:01.749
>> Professor Johnny her, professor of


01:09:01.759 --> 01:09:03.349
astrophysics at the University of


01:09:03.359 --> 01:09:05.349
Southern Queensland, standing in for


01:09:05.359 --> 01:09:07.829
Fred Watson. And thanks to Hugh in the


01:09:07.839 --> 01:09:09.349
studio. Uh Hugh couldn't be with us


01:09:09.359 --> 01:09:12.870
today. Um he got a bit confused. We we


01:09:12.880 --> 01:09:15.590
know of one planet where there is life.


01:09:15.600 --> 01:09:17.510
Hugh thought we meant that he was the


01:09:17.520 --> 01:09:19.669
only life form on the planet, so he


01:09:19.679 --> 01:09:21.829
didn't see any need to turn up today.


01:09:21.839 --> 01:09:23.430
And from me, Andrew Dunley, thanks for


01:09:23.440 --> 01:09:25.030
your company. We'll see you on the next


01:09:25.040 --> 01:09:27.189
episode of Space Nuts. Bye-bye.


01:09:27.199 --> 01:09:28.149
>> Space Nuts.


01:09:28.159 --> 01:09:30.309
>> You've been listening to the Space Nuts


01:09:30.319 --> 01:09:32.550
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01:09:32.560 --> 01:09:35.510
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01:09:35.520 --> 01:09:38.149
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01:09:40.560 --> 01:09:43.430
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