Geekout: Life in the solar system and beyond

00:00 We're back with another Geek Out episode. Richard Campbell, a developer and podcaster who also

00:05 dives deep into science and tech topics, is back for our second Geek Out episode.

00:09 Last time we geeked out about the real science and progress around a moon base.

00:13 This time it's why is there life on Earth? Where could it be or have been in the solar system and

00:19 beyond? In case you didn't catch the first Geek Out, episode 253, this one is more of a general

00:25 science and tech episode. I love digging into the deep internals of all the tools of the Python space,

00:30 but given all that's going on in the world, I thought it'd be fun to take a step back and just

00:34 enjoy some fun geekery and give you all something to sit back and let your mind dream.

00:39 This is Talk Python to Me, episode 276, recorded July 14th, 2020.

00:45 Welcome to Talk Python to Me, a weekly podcast on Python, the language, the libraries, the ecosystem,

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02:02 Richard, welcome back to Talk Python to Me.

02:04 Hey, man. It's great to be back. I'm flattered. You know, I generally don't have a guest back within

02:08 a year unless something really special happens. So, was it only February the last time I was on?

02:13 Yeah, it wasn't that. Let's see. Yeah, February.

02:16 So, it's only 100 years ago, right?

02:18 Well, February was extremely long ago and it wasn't that long ago. Like, on wall time,

02:24 it was five months. Yeah, but no.

02:26 But in societal time.

02:27 The world, everything has changed. Everything has changed.

02:29 Yeah, everything has changed.

02:30 Yeah, it's astonishing. This is the longest stretch I've been home in 10 years.

02:35 Yeah.

02:36 Maybe longer, yeah. And certainly my wife would be the first one to tell you that.

02:39 Adjusting to having you permanently here instead of having you out somewhere.

02:43 By the way, beat down that honey-do list. Like, it's nailed. But she's run out of things to keep me

02:49 doing, so.

02:51 Yeah, our house is looking pretty taken care of as well. Like, what else are you going to do,

02:54 you know?

02:55 Everybody's yard's amazing. It's really something. I'm super fortunate. I live in a great neighborhood

03:00 where most of my neighbors, at least one day a week, we all go out on our driveways and

03:05 sip a glass of wine near sunset and chat a bit.

03:09 Yeah, those types of things really are making a big difference for folks. Like,

03:13 do that as well. Meet up with people. You know, sit outside and have a beer or something that's good.

03:17 Something to connect with a broader community. It's funny how valuable that is. You don't think

03:22 about it until it's a problem, until it's a challenge.

03:24 Yeah, well, and you know, being developers, I suspect that we feel less disconnected than others.

03:30 Yeah, I think you're right. I also, you know, I work a lot in the IT space, and I realize IT people

03:34 not only were just busy because there was so much to do, but that, you know, most of your work is

03:39 crisis to crisis anyway. So, this was just another crisis to process. In some ways,

03:46 I don't think they've actually dealt with the reality of the disruption of society because

03:50 their job is calling them and they're useful and important at this particular time. But

03:55 yeah, technology's kind of saved our bacon on this pandemic, I think. Not that we're anywhere near

04:00 done.

04:00 No, we're definitely not done. Definitely not in the US for sure, but yeah, I think we're pretty

04:05 fortunate on the timing. But yeah, so five months ago, not that long ago, but again, quite a different

04:11 time. So, let's maybe start our whole story here by just summarizing what this geek out idea is.

04:19 Yeah.

04:19 Previously, you were on talking about the moon base.

04:22 Right.

04:23 This was the moon base geek out where we just dove into this concept of a moon base and how people are

04:30 going to get there, what it might be like, and so on. So, we're going to touch on something sort of

04:35 similar, but not the same for sure this time around. But you've done many, many of these. How

04:39 many did you say? Like 86 or something?

04:41 Yeah, I think we're right at 80 right now. And I have kind of stopped making them at the moment

04:45 because I'm pouring most of my research energy into the book, into the history of .NET. And it's just,

04:52 you know, it's way more consuming than I realized. Like, I've been doing more interviews just this

04:57 week as I'm getting through the body of the work and really getting a narrative of some of the

05:02 things I'm seeing the holes. And then, good news, knowing enough people that I say I know who to

05:06 fill this hole with. So, I'm going and knocking down more interviews. So, yeah, I've worked on that

05:10 bloody book for two years. And I hope I can get it done this year, but it's just been a lot.

05:15 That's a big, definitely a big project. And I know last time you were on, we talked about it.

05:19 Yeah, it was killing me then. It still is. Well, and the other thing is I've promised myself that

05:23 when the book is finally out of my head and out in the world, I will stand the geek outs up as their

05:29 own show. That people love the topic. I love the material.

05:32 Yeah, I think they deserve to be. I mean, that's 100 hours or so of really interesting,

05:39 deep research and just stuff that most people are not talking about. Definitely not at that level.

05:43 I think you're right. And if I have any particular talent, besides being just a good researcher,

05:47 is that I do adore the complexity of things. I find a lot of science communication is oversimplified

05:53 for my taste anyway. And so, getting into the more complex elements and then being able to service

06:00 them in a way that's still palatable, that you actually enjoy, hey, this is why this is hard.

06:06 You know, what we don't actually understand about these things.

06:08 Well, it's a careful balance you got to cover. I mean, I've read a lot of science for non-scientists

06:14 books, like Fermat's Theorem and other stuff that's been covered, the stuff of the Large Hadron Collider.

06:19 And, you know, some of those books, they're just dry.

06:22 Some of them are like not realistic. They don't actually, you don't really feel like you've learned

06:28 science on the other side, but there's a few clear ones that are like, do both. And they entertain and

06:34 they inform. And it's amazing.

06:35 Yeah. When you get it right, it's really something. I also think that intersecting science is too,

06:40 you know, especially when you talk about a subject as tricky as life in the solar system. It's not

06:45 just about astrobiology or aerospace engineering. It's also a lot of other aspects of biology and

06:52 physics that come into play that it's the composite of that knowledge that really gives you a sense of

06:57 what's possible in the solar system, much less beyond.

07:00 Yeah. And so, you do these two podcasts. You do .NET Rocks and you do Runners Radio.

07:04 Yes.

07:05 And in the .NET Rocks genre, every now and then, when you're not deep in a book, book authoring,

07:11 you will go and do research into one of these areas and you've been calling those geek outs.

07:16 Yeah. And really what it is, is I'm always doing the research anyway. Like my idea of a perfect Sunday

07:21 morning is tearing through a couple of scientific papers in the topic areas that I care about,

07:26 which are pretty broad based. And so, I was always making notes anyway. It was Carl's idea to

07:31 start the geek outs, which goes all the way back to 2011. And really what a geek out means is me

07:36 taking a cut of my understanding of a topic at the time and making it into an hour long conversation.

07:43 Yeah.

07:44 That's in the essence of what it is. So, when it comes to life of other planets,

07:48 I did do a geek out this in 2018. And so, when we talked about doing a show on it, I went and

07:54 looked at those notes and I looked at the new stuff that I've been gathering in that area. It's like,

07:58 so much has happened in the past two years. Like, it's just astonishing how much the understanding of

08:06 the way planets operate and the way life can exist in just a couple of years that it just,

08:13 for a two-year-old show, felt stale.

08:15 That's crazy.

08:15 It was at the time when the Cassini, Cassini had already just been de-orbited and de-orbited the

08:21 fall before I did that show in 2017. And they're still writing papers off Cassini data. They figure

08:27 there's 10 to 20 years of more writing off of what they gathered from that spacecraft. And so,

08:33 just those publications alone sort of changed the way we think about where life could exist in the

08:41 solar system.

08:42 I think maybe just, you know, understanding what is required for life is a good starting point as well,

08:49 right? Because for so long we thought, okay, we need liquid water, we need sunshine,

08:56 the Goldilocks zone you hear talked about a lot. But as we'll see going through it,

09:01 that's not necessarily the case. One thing I was thinking is, are you surprised that we've not

09:06 recreated life in a laboratory setting?

09:10 Well, there's an argument as to whether we have or not, because we're getting cleverer about our

09:15 ability to combine things. I ended up in prep for this conversation, rereading a couple of Carl

09:22 Sagan's papers. And Sagan was very, I mean, he also created the, you know, searcher, extra,

09:29 life, right? SETI, as well as a whole bunch of other things. But he worked really hard on what

09:34 would you do to detect life? And what, you know, what would that even look like? And broaden our

09:40 understanding of it. So, you know, one of the things that came out of an awful lot of that research was

09:44 that the ingredients for life are pretty much everywhere. So now it's really about cooking technique.

09:54 You know, how do you assemble them? What is the perfect mixture? And so the whole idea of the

09:58 Goldilocks zone is, this is the point at which a planetary-sized body orbiting a star can have

10:06 liquid water on the surface, which was firmly, you know, at the time believed in a necessary

10:12 requirement for life. And so as we've started imaging planets around other stars, and there are

10:16 different kinds of stars, like brown dwarves, like very dim stars, that Goldilocks zone is

10:23 tremendously closer to the star. But that has other side effects, like almost certainly when you have

10:28 close orbiting bodies like that, the body will end up being tidally locked. So you can imagine the

10:34 effect that you'd have on the Earth if it was orbiting a star, but one side of the planet faced the star

10:39 all the time. That is, one side is always lit and one side is always dark. Well, that's going to cause

10:45 some troubles, right? You know, there's some impacts.

10:47 Yeah, you think about just the tilt that causes winter and summer, it's super minor.

10:51 Well, and yet, I think incredibly important. It's when you start looking at the different bodies in

10:56 the solar system, you see that it's only those small variation differences that may be crucial.

11:02 I would go a step further, and this is like even more recent reading, is that are the continents

11:08 essential to life. Not that they're land masses, but that they force warm water to circulate away from

11:16 the equator and up towards the pole. So what we've known as the North Atlantic conveyor is a pump system,

11:24 essentially, that exists in the ocean where water is warmed in the Gulf of Mexico and then is drawn

11:30 up the eastern seaboard of the United States all the way to the Arctic, where the ice there drives that

11:36 water down, cools it, and that creates this pump. And the side effect of that is the North Atlantic

11:41 is substantially warmer than it ought to be. And so it provides more rain and more heat to the northern

11:51 latitudes into Europe, which makes them far more habitable.

11:54 Yeah. Yeah. Europe is super far north, much more than my conception of it relative to other places.

12:01 Sure.

12:01 I think that's partly why, right?

12:02 And in fact, we have evidence now that in the around 15, 1600s, the conveyor broke down to some

12:10 degree, and they called it the Little Ice Age, that in northern Europe, where people were already

12:13 living, winter got dramatically worse. The canals of Amsterdam froze. So it makes a big difference.

12:24 It is part of the dynamics of what makes a habitable world. Where can life evolve and advance?

12:29 There's a lot of different ingredients in that.

12:31 Yeah, absolutely.

12:32 Absolutely. Well, let's start our exploration of this whole idea with what I think of as the two

12:40 classic thought problems or thought experiments here. And that would be Fermi's paradox and Drake's equation.

12:47 Right. And so Enrico Fermi and father of the atomic bomb, you know, after becoming in the destroyer of worlds,

12:57 and then, and to his credit, then staying in the process to stop humanity from using them successfully,

13:02 I might add, so far, then came up with that whole, you know, his paradox was given that astronomy is

13:10 showing us just how many stars there are and how many galaxies there are, the inevitability that even

13:17 if a tiny fraction of the planets that exist can carry life, where are they? Because there should be lots

13:23 of them. Yeah.

13:25 You know, it's just, it didn't make no sense. And it was Frank Drake that went deeper into that as part of

13:31 the gap, the original SETI gathering, where he started building this probabilistic formula known as Drake's

13:36 equation that sort of went down to how many stars have we got? What's the rate of new stars being made?

13:42 How likely are they to have planets? Are they in the conditions to support life, which is a big factor of this?

13:49 And then does life actually evolve? What's the likelihood of that? Does it actually advance intelligence?

13:55 And then can it communicate in a way we can detect? And then how long that lasts as a society before it either...

14:03 Right. Before society breaks down and the preppers will break and whatever, right?

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14:59 Or perhaps evolve away. You know, there's a group of thought that says that the actual purpose of a

15:07 universe is like every other composite creature to make more of itself. And so one of the possibilities

15:13 is that in the end, a successful universe is one that creates conditions where advanced biological life

15:20 can form, become intelligent, develop technology that ultimately leads to being able to make their own

15:26 universes. You know, which one of the ways you could answer Drake's equation is say the reason we haven't

15:30 heard from any of other life forms is that the window between you developing technology and being

15:35 able to make your universe is a few thousand years and then you're gone. You've moved on. Why would you

15:42 hang out in this universe? You can make your own.

15:45 Right. You made your wormhole and you've got the actual perfect place you've designed and all that.

15:50 I mean, you could look at it the same way as when you climb out of the cave or you climb out of the

15:54 ocean. Like it's just the next logical evolution of an intelligence is to go make universes.

16:00 Yeah. And the math of Drake's equation, you know, you think about the math when you do as,

16:06 you know, astrophysics and astronomy, relativity, all that stuff is insanely complicated.

16:13 I mean, we know so much more now. In 1961, when he writes that equation, we did not have a good

16:17 count of stars and star formation. We certainly do now, right? We know that roughly three solar

16:23 masses worth of stars are formed in our galaxy alone every year. So it might be one big star. It

16:29 might be a bunch of little ones, but like it's a constant thing. We know that virtually every star

16:34 we've ever looked at that we're able to see reasonably with our exoplanet systems has planets. Planets are

16:39 super common. Like everything. That's recent news, right? Yeah. That's in the past years. Within 10

16:43 years or so, this is a certainty, not a speculation. Right. Because we're counting them. We're finding

16:49 them. We're getting better at finding them. We're even getting better at finding ones in the Goldilocks

16:53 zone and likely rocky, roughly 1G worlds for, you know, when our first sensors were being used to find

17:01 exoplanets, we could only find hot Jupyters, stuff that's Jupyter-sized or bigger orbiting very close to a

17:07 star because our senses weren't that good, right? We weren't able to measure the wobbling stars well

17:13 enough to sense something small so we can sense something big. So one of the arguments was,

17:17 yeah, there's lots of planets, but they're not good ones. But now as the sensors have gotten better,

17:22 we are being able to say that rocky worlds seem to be pretty common too. So every hardening number,

17:28 every maturing estimate that we've got around Drake's equation points to more, not less,

17:35 until you get into this life part. What does it really take to support life? And there's where our solar system

17:44 suddenly is a great example because we have other planets, some of which, you know, especially when you look at

17:50 something like Venus, it ought to be life-sustaining. What's going on there? And again, in the past few years,

17:57 our knowledge of that has expanded dramatically.

17:59 Yeah. Yeah, absolutely. So Drake's equation is this interesting, basically seven or however many

18:05 factors, ways to speculate because the math is just independent probability times independent

18:10 probability.

18:10 Right.

18:11 Out pops another number. And so let's try to put some concreteness around the speculation,

18:17 I guess. Let's just look at here. Like we know there's life on earth. You and I were talking,

18:21 we're pretty sure we're not in a simulation.

18:23 We're not sure about that at all, but close enough. You know, probability says that we're almost certainly

18:30 a simulation.

18:31 Yeah. Yeah. So let's just, you know, it's a little bit like you started off, right? Like we think that it

18:37 was the sun and the liquid water on the surface and all of that, that turned out to be most important.

18:44 But then people started going into the ocean.

18:46 Yeah.

18:47 And finding volcanic vents and that kind of broke, broke some stuff.

18:51 The Woods Holes finds in the Galapagos is where they first found, they speculate. Again,

18:56 you always have amazing people who can come up with an idea that, hey, look like there's volcanoes

19:02 and there are above ground volcanoes have vents. Why wouldn't underground volcanoes have vents?

19:08 In fact, why wouldn't there be vents everywhere? And so then they build a theorem around that and

19:12 say, well, we should be looking for warm spots in the deep water. And so then they build a sensor

19:17 array and drag it behind a ship, which they did in the Galapagos, which is, Galapagos is very much

19:22 like Hawaii in the sense that it's literally just a chain of islands made from volcanoes.

19:25 And they found evidence of potential vents. It leads in the late seventies to the Alvin

19:32 submarine going down and they find clams in the bottom of the ocean. Like what the heck is going

19:37 on here? And they follow this trail of clams to a black smoker, to a hydrothermal vent spewing

19:44 iron sulfites into the water and the water 700 degrees Fahrenheit, like screaming hot. And it's

19:52 surrounded by life. Some of it is, is like surface life, like clams that have found a new ecological

20:00 niche living in the dark, surviving off of the, the plankton that grows around that vent. Some of it is

20:07 unique to the area, the tube worms and other strange critters. It's just like here, which should have been

20:13 nothing, should have been a desert at the bottom of the ocean. There is this wellspring of life in the

20:19 absolute pitch black, but there are, is chemical and thermal energy available. And so that, you know,

20:25 that sort of changed the math. It just said, Hey, as long as I have energy in the form of chemistry and

20:32 air and heat and still water, water may be the undeniable one, the intractable one. You know,

20:39 that science fiction used to speculate around the idea of silicon life. I just read a great paper where it

20:45 said, Hmm, you know, so we like silicon as potential life because it's just one tier down on the

20:52 periodic table below carbon. We know we have carbon based life. We are carbon based life. And so if you

20:57 stay in the 14th column, you go down one, you get silicon. And it is also a tentatory atom in the sense

21:04 it'll make four bonds just like carbon will, but it doesn't make them anywhere near as well as carbon does.

21:09 And so it probably doesn't work and it would need, and they get into this idea of carbon combined with

21:16 water. And you really need to throw some nitrogen and they call it chon, right? Carbon, hydrogen,

21:21 oxygen, nitrogen. You get those basic elements together. That's all of organic chemistry more or

21:26 less.

21:26 Yeah. More or less.

21:28 And so the water, which might not be optional. The good news is every bit of astronomy we've done

21:33 shows water is everywhere. Water is just, it's not even, it's not even, and in fact,

21:39 your amount of available water tells an awful lot about how your planet's doing one way or the other.

21:44 So water's pretty common. Carbon, pretty common. Like we're doing all right in those respects.

21:49 We could probably find life anywhere those things exist.

21:52 Right. And we found water in the craters on the moon. We found evidence at least of water

22:00 in Mars. There's...

22:02 Yeah. We're pretty sure there's actually a lot of water on Mars now. We're just being a little

22:06 careful going too near it because there's almost certainly life in it. And we don't want to

22:11 accidentally destroy it.

22:12 Yeah. That'll be amazing. You've got Venus, which has evidence of something flowing a lot on it.

22:19 You look at the shape of the ground.

22:21 Yeah. The Venus Express mission, which is still in orbit today, but it did a lot of the detailed

22:26 map, modern mapping of Venus. So it definitely shows ocean bases and things like that. It also shows

22:31 over a hundred large scale active volcanoes scattered around the planet. So, you know, and by large,

22:40 I mean like big Hawaiian Island large, right? Mauna Loa, Mauna Kea, but a hundred of them.

22:48 Like, okay. So there's a reason why there's a lot of sulfuric acid in the atmosphere of Venus.

22:52 Right.

22:52 But one of the things that they really dug into from there is they said, well, look,

22:57 seeing that the ingredients are so common, but clearly Venus isn't like that anymore, right?

23:00 Like surface of Venus is 90 times atmospheric pressure. It's 900 degrees Fahrenheit there.

23:06 Lead will melt on the spot. The toughest Soviet lander ever made, Venera 11, lasted two hours on the

23:13 surface before it broke down. Like it's not fun down there, but it doesn't look like it was

23:18 always like that. That a billion years ago or so, Venus was a water world, that it had oceans,

23:25 but something went wrong. And the went wrong seems to be the magnetic field. The magnetic field of

23:33 Venus was not strong enough to repel solar wind. And in the end, solar wind's nothing magical. It's

23:39 the by-product of fusion of the sun spews a constant stream of highly charged protons from the star all

23:49 the time. And it hits everything all the time. And because it's highly charged, it's magnetically

23:54 sensitive. So our very strong magnetic field on the earth pushes those protons away. It actually,

23:59 and if they're low enough energy, it'll capture them in the Van Allen belts. But the main part is that it

24:04 doesn't get to the atmosphere. Because when a high energy hydrogen atom shows up like that, it finds

24:10 itself another hydrogen atom. They like to be in pairs. And so it'll rip a hydrogen atom out of the

24:16 atmosphere in a big old hurry. The typical place it's going to get it from is a water molecule. So it'll

24:21 yank a hydrogen on. One of those high energy solar particles is going to grab a hydrogen atom off of a

24:26 water molecule and head off into space. And then you'll end up with a hydroxyl radical, an OH,

24:33 which is then going to try and combine with something else. Or maybe that other hydrogen will get ripped

24:37 off as well. And then you have elemental oxygen. And elemental oxygen does not like being elemental.

24:42 It finds a home.

24:44 Yeah.

24:45 And so it grabs whatever it can find. And in the case of Venus, it grabbed carbon atoms and turned

24:51 Venus. Venus gradually lost more and more of its hydrogen. And all of that oxygen found home in

24:57 carbon. And you had a ton of carbon dioxide until you get the atmosphere of Venus that you have now.

25:03 Which is incredibly dense, as you said.

25:05 Yeah.

25:05 90 times, even though the size of Venus, the gravity of Venus is about the same.

25:10 It's not like Jupyter or something, say.

25:12 No.

25:13 But yeah, it's just turned into this hot, dry place.

25:16 Yeah. But gravity is not the thing that protects an atmosphere, it appears. It's the magnetic field

25:21 that makes the difference. And pretty much the same thing has happened at Mars. It's just that Mars

25:25 is further away. And it's smaller. Right? It's only half the size of Earth. Right? We always think of

25:31 Mars as close to Earth. Venus is way more related to Earth than Mars is. But Mars, too, was once a wet

25:39 world. Our detailed maps from the Mars Odyssey and other mapping satellites has shown us where oceans

25:46 ran. And in fact, still seeing occasional bursts of water come up, bubble up onto the surface and roll

25:52 down hillsides and then disappear again because of sublimation because the atmospheric pressure is so low.

25:58 But same thing happened. The hydrogen got stripped away. The oxygen found a home. It made a carbon dioxide

26:04 atmosphere. Granted, it's a very weak one. It's also why the planet's red because it bombed with all of

26:08 the iron it could find and turned the planet red. But in both cases, it's the weak magnetic field that

26:14 has been the big difference maker for that planet.

26:18 People mostly think of Mars as where, as like the old Earth or whatever. Right? Long ago, it might have

26:24 been like that because Venus is so different with its temperature. But...

26:28 Yeah. But they're both of the same result. If you make a heavy-duty dense carbon dioxide

26:32 atmosphere, you get a runaway greenhouse effect. If you don't have enough mass to hold on to your

26:37 atmosphere well when the atmosphere is dripping, you get a dry desert like Mars.

26:41 Yeah.

26:41 But they were both likely wet worlds and quite possibly had life on them. Whether or not any of

26:49 that it survived now seems unlikely. But NASA's been admitting that they want to be really,

26:55 really careful around any native life on Mars. And their protocols for putting stuff down on the

27:03 surface of Mars to detect life are strict enough that they generally don't want to build spacecraft

27:08 that way because they need to sterilize the spacecraft so thoroughly that it's actually hard to make a

27:12 in order to really sterilize, to kill bacteria that will survive the journey in space to Mars and re-entry,

27:20 you have to bake the spacecraft at incredibly high temperatures. And most spacecraft don't survive

27:26 the baking process. So, so far with the missions they've been sending to Mars, they stay away from

27:31 areas that are likely to have life so that they don't have to follow those steeper protocols.

27:36 Right. And how certain are you that a little tiny bit didn't get through, right?

27:40 Yeah.

27:40 It's microbiology.

27:41 Constant concern. Well, and a great example of this is the, the Israeli Mars lander had

27:47 tardigrades on it. The lander was supposed to do an experiment with tardigrades, which are often

27:53 called water bears. There's these little microscopic critters that are insanely tolerant to harsh

27:59 conditions, insanely tolerant to being dried out and being wet and brought back to life again,

28:04 to hard radiation conditions and so forth. So tardigrades are great, interesting things to experiment

28:09 with. Well, the bear sheet lander didn't make it to the moon. It hit the moon just with a little bit

28:14 too much of vigor. Yeah. You can, you can see a lunar carnesis orbiter picture of where it landed. It's a

28:19 big old splat, but there's also a conversation that says, the tardigrades probably survived. We have

28:25 contaminated the moon with water bears.

28:28 In that little tiny spot. In that spot. Yeah. Now I don't think they're going to rise up and

28:33 repent, you know, and attack us someday, but it speaks to the reality that when you get down to

28:40 microscopic life, they were incredibly resilient and our risk of contamination is really significant.

28:46 And this gets into this really interesting ethical discussion around.

28:50 How do you look for life? If it's almost like quantum mechanics, right? The process of looking destroys it.

28:55 It's like, if you observe it, you may change it. Yeah.

28:58 You better, you got like one shot to check is life here.

29:01 Yeah. And how you check it. And then you want to study it over time, right? And so the more we've

29:06 learned about Mars, the more we've come to appreciate that there's very likely briny liquid water

29:12 under the surface. You know, one thing we have not done much of in all of our explorations of Venus

29:17 and Mars and the moon and so forth is really dug into the ground at all. And so you don't know what's

29:23 going on a few feet down, you know, the earth itself, depending on where you dig transforms

29:29 amazingly as you dig down, you know, the first meter is one thing. The next 10 meters, something

29:36 else, a hundred is something else. Again, the first kilometer again, and so forth on down.

29:40 We just don't know for sure. But as the models have gotten more coherent and reliable, it looks

29:47 like there's briny liquid, you know, salty water subsurface of Mars, and it almost certainly

29:53 has bacterial scale life in it. And because the question is, is it worth constructing a mission

29:59 to do that, to actually test for that safely, which is very challenging to do, to teach you

30:05 exactly what other than to assert for sure there's bacterial life on Mars?

30:10 Right. And that would be interesting, but you know, how significant is it?

30:14 Very true.

30:14 It would be much more interesting to find creatures that move around in some way, right? And so that

30:21 brings us back to, well, if it's actually the magnetic field that matters, other places around

30:26 you have magnetic fields as well, right?

30:28 Well, and part of what led us to that understanding were the Galileo and Cassini missions out to Jupyter

30:37 and to Saturn respectively. Because there you've got an epic magnetic field. It's just not your,

30:44 the moon's field. It's this gas giant's field. And there's no solar radiation getting in that. In fact,

30:50 you get more radiation off of the host planet than you do from the sun once you get it to that scale.

30:56 Saturn has crazy radiation, right?

30:57 Yeah. And so does Jupyter. And pretty much for the same reason is you compress gas to that point.

31:02 Like they talk about metallic hydrogen and things being down there. You create these electromagnetic

31:07 fields from the friction of everything moving around that they're incredibly destructive. It

31:13 certainly will kill any human that gets anywhere near it. But making electronics that tolerate that,

31:19 you wonder why these space missions are so expensive. It's really tough to make hardware that can

31:25 tolerate the radiation exposure that they get. And they don't orbit in neat, tidy orbits the way you

31:30 think about it from science fiction. And both Galileo and Cassini did orbits where they got a long way

31:36 away from the gas giant on a regular basis to decrease their radiation load as well. It helped them also

31:41 do maneuvers. When you're at that far apogee, when you're further away, it takes very little fuel to tweak

31:46 your orbit and be able to make a close pass on a different moon. But it also means that you have

31:52 shorter bursts of time at higher speed in those strong radiation belts.

31:56 Right. You went by them really quick, take your measurement and get out.

31:59 But speaking of detecting life, the Galileo mission, which flew back in 89 out of a space shuttle back

32:05 when A, space shuttles operated. And B, they were still launching satellites, which they stopped doing

32:10 because it finally clued into someone after that how dangerous it was to put a rocket engine inside of a

32:15 space shuttle full of fuel when you're going up. But what was cool about, many things were cool about

32:22 the Galileo mission. Its mission to Jupyter was great. But part of the way that it got to Jupyter is it

32:26 actually did a slingshot maneuver off of Venus and then another one off of the Earth on its way out,

32:33 which took it about six years. But it was Sagan. Remember him? Carl Sagan.

32:39 Who said, hey, can we craft an experiment for Galileo to detect life on Earth?

32:47 Like given this limited sense of sensors that we're going to send to Jupyter to go look at the moons

32:54 and go to Europa and all those cool things, what would we do to actually detect life on Earth?

32:59 And so he was primarily using spectrographs. So he's imaging the atmosphere to read it and say,

33:06 what are the unique signatures in Earth's atmosphere that are life indicators? One of the points he made

33:13 in this paper from 93 was that there's atomic oxygen in the atmosphere. Because oxygen doesn't like being

33:20 on its own, it always is going to find something to combine with. The only way you would measure atomic

33:26 oxygen in the atmosphere is something is producing it constantly. And his argument was that is almost

33:33 inevitably life. Like he really can't think of another model that is constantly producing

33:40 oxygen. In our case, it's plants, right? Plant life rose first in the form of algaes on the Earth. And

33:46 it's what pumped oxygen into our atmosphere that created all these possibilities, right? Our ambient

33:52 atmosphere was mostly nitrogen before that. It wasn't until plant life really got going that we started

33:59 having ambient oxygen. But he also indicated that methane was an interesting indicator as well in

34:06 combination with oxygen. Methane is super simple. It's a carbon and four hydrogen atoms. It is created in

34:12 space all the time, right? Cosmic gases form into methane regularly. And if you've got lots of methane,

34:20 methane is probably created that way. But methane does not exist in amongst atomic oxygen very easily.

34:25 So where it does exist, it means there's some kind of what they call metagenesis going on,

34:30 or something, some process is making methane, and it's probably life. And so, you know,

34:36 the most famous methane producer on the planet for most people are cows, right? Because they ferment

34:42 their cud, their grass, and a byproduct of that is methane, which they mostly burp out, not the other

34:48 way. But it is an interesting indicator that mixture of atomic oxygen and methane is probably a really good

34:54 measure of life. And the delicious part of this, and it's one of the reasons I bring it up in this story,

34:59 is so he writes that in 93, makes that postulation, and years later would find that exact mixture

35:07 elsewhere. And we'll talk about that when we get there.

35:10 Yeah, for sure.

35:11 And essentially, you know, the Galileo mission was focused on Europa, which is an icy moon in orbit around Jupyter.

35:17 Yeah, and we have all these moons around Jupyter, right? And Saturn, I don't remember which,

35:22 but it's like 20 to 80.

35:23 Yeah, I think you're over 80 for Saturn alone now. Because when you start sending spacecraft

35:27 close enough to actually orbit, you know, the Voyager missions were just flybys.

35:31 They whizzed by Jupyter and Saturn. They saw a few things. But when you, you know, Galileo

35:36 orbited around Jupyter for years, and so found a lot of moons, as opposed to, you know, the

35:41 ones that Galileo, Galilei saw from a primitive telescope. He saw the first four.

35:46 Yeah. But isn't it supposed to be cold out there?

35:49 It is very cold. There's no two ways about it. And that was the expectation, right? Is that

35:53 we're going to go see ice balls. And then when they actually imaged Europa, they found there

35:58 were cracks in the ice. I mean, that makes no sense, right? Like, why would there be cracks

36:02 in the ice? And not only that, but wherever there was cracks, there was red. Sort of a muddy

36:08 red brown.

36:09 Well, here comes Sagan again. They eventually, they were trying to figure out what it was,

36:16 and they had this theory that it was a chemical compound. And so they started making it on Earth.

36:21 So take your common cosmic gases, the stuff that naturally forms, like methane and ethane,

36:28 ammonia, hydrogen sulfide, those kinds of compounds, all relatively simple compounds,

36:33 carbon with a bit of hydrogen, nitrogen with a bit of hydrogen, that sort of thing. And then expose

36:38 it to ultraviolet light and a few cosmic rays. And it changes. It changes into a weird reddish

36:45 substance that is actually really tough to measure. For a long time, they called it star tar, which is

36:52 a good name.

36:52 Okay, yeah.

36:53 But ultimately settled on tholine, which is derived from the Greek word for muddy, because it is kind

36:59 of a sticky, muddy substance. And so the theory goes that you have these common compounds, and then

37:06 they come to the surface and get irradiated. And then that irradiation turns it into these sort of

37:12 primitive compounds. And we've, since Europa was really the first time we saw tholines in substantial

37:18 amounts all along the cracks in Europa's ice. And we've seen them elsewhere since then.

37:24 So the model for what made Europa interesting then was this combination of a very strong magnetic field

37:31 from Jupyter, also very strong tidal flexing, so that the gravitational pull of Jupyter is so strong,

37:38 it flexes Europa regularly, which keeps the core of Europa warm. And so the estimates now is that there's

37:44 a hundred kilometer deep liquid ocean underneath the ice of Europa.

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38:37 And that flexing has got to be causing some volcanic-like behaviors.

38:41 Yeah. They call cryovolcanoes, right? That you get these bursts of warm water, above freezing water,

38:47 that bubbles onto the surface, carrying these simple compounds, your methanes and ethanes and ammonia

38:54 and so forth, onto the surface, where it gets irradiated by the sun and turns into tholans.

39:00 Yeah. And I would point out that Arthur C. Clarke, who to this day I am still convinced is actually

39:04 a time traveler and didn't die, but rather went home, who predicted geostationary satellites 20

39:10 years before anybody could fly them, also wrote in the book 2010, his sequel to 2001 A Space Odyssey,

39:15 that the star people said, "All these worlds are yours, save Europa, attempt no landing there."

39:22 And the first time we get a good look at Europa, it looks like there's something there.

39:26 Yeah. That's insane. That was such a great imaginative story. And wow, I didn't realize that part.

39:33 Oh, I remember when the paper, when the stuff came, the reports came out, I looked at it,

39:38 and it was like, "How? How did he know? How did he? He keeps being right. It's crazy."

39:46 Yeah. That is totally crazy. Totally crazy. Yeah. I would love to see us go, go there even with that

39:52 warning, maybe. I don't know. I mean, the problem is once you go there, the clock is ticking for at

39:58 least very small microbiology.

40:00 Well, there are mission proposals like this thing called Jupyter Express where they want to put a

40:06 lander down on the ice close to one of those cracks. They want to melt their way through the ice and drop

40:13 a submarine down. Yeah.

40:15 And motor around in that ocean. Get a nuclear space heater or something.

40:17 You guess what you're going to need, right? A radiothermal generator, which is generally what they

40:21 use out there anyway, because there's not enough sunlight to really make solar work. And most of those

40:26 RTGs generate four to one heat to electricity. So your typical RTG, like the one that's on the

40:34 Curiosity rover on Mars, is generating a hundred watts of electricity and 400 watts of thermal, of heat.

40:41 So you could get a big one and put it down on that ice, and it's not only making electricity,

40:47 so it's still able to communicate to the surface, but it's also generating enough heat that instead

40:50 of you trying to dissipate it, you're actually pumping it into the ice to melt your way through it.

40:54 Yeah. And now you get into the question, like, knowing what we know now, that there's

40:59 almost certainly liquid water down there, and it's caused by these tidal effects,

41:04 which means there's cracks in that core. If it's warm enough, maybe there's hydrothermal vents down

41:09 there. And knowing what we find in our hydrothermal vents, what would we find in their hydrothermal vents?

41:14 Yeah. It's exciting. It's absolutely exciting. And another place that's in this kind of realm is

41:21 Saturn and its moons. Mm-hmm. So, you know, the Galileo mission was the late 80s, early 90s.

41:27 Cassini was one of the last of what they called the great observatories. They built these huge

41:31 spacecraft. They don't build them this big anymore. Cassini was a tank, arguably one of the largest

41:36 explorer spacecraft ever built. It was literally the size and weight of a large school bus, of a full-size

41:43 bus. And I did, you know, almost six metric tons. Wow. That's like four cars, three cars.

41:48 Yeah. A huge machine. And left in the late 90s, got to Saturn in 2004, operated for 13 years. It was

41:55 originally planned for a three-year mission, but they kept extending it. And in fact, they intentionally

42:00 de-orbited it. Because what they found in the moon system of Saturn was so profound that they weren't

42:07 willing to take a chance that Cassini might accidentally crash into one of the moons when

42:12 they lost control of it, when it ran out of fuel. And so instead, they intentionally de-orbited it

42:16 into Saturn's atmosphere. And it sent data right up until it lost control. It hit enough of the

42:22 atmosphere that it started to spin. But the story of Saturn's, the exploration, I mean, of course,

42:27 the big one was to see Titan. And Titan is the largest moon in the solar system. In fact,

42:31 Titan is larger than Mercury. You know, it'd be a planet, except that it happens to be orbiting a gas

42:37 giant. And the Voyager missions had imaged it well enough that they knew it was completely clouded

42:42 over, incredibly dense atmosphere on it. And so they had a lander on the Cassini mission called the

42:48 Huygens probe to land on the surface of Titan. And what it found, there's a great video they composed of

42:56 all of the photographs of that, the Huygens probe as it descended by parachute down to the surface.

43:02 It looks like a wet world. The problem is it is extraordinarily cold. It's that negative 290

43:08 degrees Fahrenheit on the surface. So like, bring a jacket, right? It's cold. And so the atmosphere is

43:14 almost entirely nitrogen with traces of ethane and methane. And in fact, there's ethane and methane

43:20 clouds that rain onto the surface and cause erosion. And there are lakes, bodies of liquid on the surface

43:28 of Titan. It's just, they happen to be liquid methane. Oxygen, it's cold enough that oxygen is frozen solid

43:34 there. So you would be able to mine oxygen if you get there. And the atmosphere, the pressure on the surface

43:40 there is about 10 times sea level pressure, 10 bar.

43:43 Is the atmosphere thicker?

43:45 It's very thick. And again, it's a decent size. It's not a huge thing, but it's big enough.

43:49 But you see your gravity is low enough and your atmosphere is thick enough that if you could

43:53 get a warm enough coat and a respirator so you could breathe, you could probably strap a couple of wings

43:59 onto your arms and fly. Just flap. It'd be enough. You've got enough atmosphere to push against and a low

44:05 enough gravity, you could probably fly around tight.

44:07 Wow. That would be insane. It'd be kind of like swimming, but in the whole sky.

44:12 The problem is that at that level of cold, everything is brittle and hard. It'd be very

44:18 challenging to function there. But it is, if you were picking candidates for places that humans could

44:24 live, that's one of them. We just have to solve certain challenge, you know, non-trivial problems.

44:30 But the atmosphere is thick. Is there life there? It's awfully cold. The water, there is

44:37 absolutely water ice, but it will be like rock. So, intensely hard.

44:42 Yeah. So, maybe, maybe not. Who knows?

44:45 But that was the, you know, their plan for Cassini was obviously to drop the Huygens probe on Titan,

44:51 because this amazing moon. But they were generally going to image all the moons. They wanted to find

44:55 some Europe and so forth. And it was the Settilus that stole the show.

44:59 Yeah. Absolutely. Settilus is the sixth largest moon of Saturn. So, it wasn't high on the rank.

45:04 They expected it. Well, the only thing that was interesting about Settilus going in with Cassini

45:08 was it had the highest albedo of any moon. So, it was incredibly white, very reflective. So,

45:15 it was expected that it was incredibly white because it was an ice ball. It was just covered in ice.

45:19 And so, it reflected a lot of light. And so, after a few orbits in from the initial mission,

45:24 one of those orbits was going to get close enough to Settilus that almost as an afterthought,

45:27 was like, "Ah, we should snap a couple of pictures of Settilus." Like, they weren't planning on doing

45:31 anything substantial with Settilus. And then one of those pictures, when they got it back,

45:35 there was a cryo geyser erupting on the southern half of Settilus. And it was visible in the photograph.

45:42 Right. It was, they were somehow between the sun and then a Settilus and then the spaceship,

45:48 right? So, they caught it in the light. They caught it in the light. They could see the cryo. And again,

45:53 totally unexpected. And to NASA's credit, they rewrote the mission at that point.

45:57 They just redid it. Okay. That's now an important body. Let's figure out how we do more passes on it.

46:05 It's active now. We need to see this thing now. And so, while they still mapped a tremendous number

46:12 of moons for Saturn, and it's over 80 now, and they got pictures of all the other bodies and some great,

46:19 and learned more about the rings, figured out that there's a cloud formation on the north and south

46:24 poles, that it's hexagonal. Like, they learned astonishing things about Saturn.

46:29 Yeah. But they really studied the heck out of Settilus to the point where they decided,

46:34 as they were getting towards the most extended parts of Cassini's mission, they were going to take

46:39 a chance. And they made a pass, past the south pole of Cassini, of Settilus, within 12 kilometers.

46:46 And ended up flying through a geyser pole. Wow.

46:50 And to the point where the spacecraft almost lost control and spun out. They genuinely,

46:55 that thing got splattered with that cryo geyser. They took an incredible chance with this machine.

47:01 They hit like a hose type of thing at 20,000 miles an hour or something, right? I mean, that's crazy.

47:07 You know when you're bombing down the highway, and the guy in front of you washes his windshields,

47:11 and it lands on yours? That. In a billion-dollar, six-metric-ton spacecraft,

47:18 120 million kilometers away from a pit stop. But the byproduct is that they caught some of that

47:24 material. And they measured it. And you know what they found? What?

47:27 Atomic hydrogen and methane.

47:28 Oh. How interesting.

47:30 It's the same stuff that we'd measured with the Galileo spacecraft. Like, in the right ratios,

47:37 where it's like, something biological could have made this. And that is just a, you know,

47:42 from what they thought was an icy ball that wasn't interesting to, we have measured unstable compounds

47:48 in the effluent of this moon that indicate something down there is producing it.

47:55 And lots of water, right?

47:56 Well, there's a lot, yeah, certainly plenty of water and briny water, salty water, and a bunch

48:00 of other hydroxyls, other light compounds, again, unstable compounds. But that experiment that Sagan

48:05 had done 20 years before with the Galileo spacecraft, and that piece of research to sort of map neatly onto

48:12 the data set they got back from Cassini's fly-through of the Enceladilus cryo-volcano,

48:17 or cryo-geyser. And it just, you sort of hit, you sit back and you see and go, "What have we found?

48:22 Look, what do we know now?" And of course, there's Tholans all over Enceladilus.

48:25 And of course, there's a lot of other things that are going to be found in the world.

48:29 And of course, there's a lot of other things that are going to be found in the world.

48:31 And of course, there's a lot of other things that are going to be found in the world.

48:34 And of course, there's a lot of other things that are going to be found in the world.

48:36 And of course, there's a lot of other things that are going to be found in the world.

48:37 And of course, there's a lot of other things that are going to be found in the world.

48:39 And of course, there's a lot of other things that are going to be found in the world.

48:43 And then Europa to do it to Enceladilus. It's a little bit further out because you're going out

48:47 to Saturn. It's a smaller ball. And it's certainly active, right? So, I mean, one of the challenges

48:53 you have here is like, we can see all of the evidence of potential life on Mars, but it's traces

48:58 from the past. There may still be some hanging on in a subsurface sea, but this is way more active.

49:06 It's just a long way away. Right. And what you would find in Mars is probably just biological,

49:12 as you already said, right? Whereas this, I mean, there could be something like a whale down there.

49:16 Who knows? I would hope for like a barnacle, dude, right? An idea of a filter feeder that means an

49:22 ecosystem exists where there's microscopic life that eats other really small life that ultimately

49:27 gets to a filter. Like that would be astonishing. The most, you know, the higher probability is a slime

49:33 mold, but you know, okay, life. And yeah, but what's interesting is seeing that this theme happens over and

49:41 over again, that when you have a combination of strong magnetic field that protects the atmosphere

49:45 from solar stripping, and you have some heat in the form of tidal forces or core heating,

49:53 and you have liquid water also generated by those things, you have these elements come together again

50:00 that show the precursors to life, or to at least, or the evidence of relatively simple life.

50:06 Yeah. Well, really quickly, I know you guys had Ron Connery, Rob Connery on your show.

50:10 Yeah.

50:11 And he had written an interesting book called The Curious Moon, which is like a learn Postgres,

50:16 the database.

50:17 Yes. But his sample data was NASA's and satellites data. And what's lovely about that is not only is it

50:24 super real and so forth, and it's a fun book. And I actually helped him edit it. I was one of the early

50:30 readers on it as well. And we argued vociferously about it. But it is really a good teaching tool.

50:36 But NASA publishes absolutely everything they gather. It's part of their basic policies.

50:41 And so including that data is the fact that they actually changed the data structure halfway through

50:44 the research when they went to the second phase of, and they're like, I don't like this data

50:48 format. We're going to ship this data format. So you have all those problems.

50:50 Yeah.

50:52 And Rob is a friend, and I think his book is brilliant, and we all should own it. If you

50:56 want anyone who wants to learn Postgres, there's no nicer way. And you'll work,

51:00 and the story he tells is a fictionalized story based on real data is delightful, like just a

51:05 really a fun thing.

51:06 But that's cool. I definitely want to check it out.

51:08 Yeah, I totally encouraged you.

51:10 So what we've covered so far was on my radar. These are things that I at least knew about.

51:14 I knew about the geyser. You know, you look at Venus, and it obviously has what looks like,

51:21 Grand Canyon type of structures in it and whatnot. But it turns out if you look farther,

51:26 there's still interesting stuff out there that was not on my radar.

51:29 Well, and I'll skip over the other two gas giants, Neptune and Uranus, for no other reason than we just don't have good data. We've never had a Cassini class mission out

51:38 there. There's a big pitch right now to send a major mission to Neptune. It would still take a

51:43 decade plus to get there. But we happen to be recording this almost right on the five-year

51:48 anniversary of New Horizons getting to Pluto. And, you know, New Horizons is a very unusual mission.

51:54 Pluto is a weird orbit. It was only discovered in 1930. It does not orbit on the ecliptical plane of all the other planets. It's tilted. It also crosses into Neptune's

52:06 orbit and then passes back out. And in fact, when they were proposing the New Horizons mission,

52:10 what they're saying was like, "Listen, we're at a point right now where we can get a couple of good

52:14 gravity slingshots and get something there in a reasonable length of time, right, in 10 years or so.

52:20 And if we don't do it now, we won't be able to for like 50 years." Wow.

52:23 Wow. And so they got the budget. And it's a relative, it was a quite a small spacecraft.

52:27 It's about the size of a piano. And I mean, like a baby grand piano. And it's actually triangular

52:31 shaped. And it was actually the fastest moving vehicle we ever made. It did a direct ascent to

52:38 Earth escape. Like generally, you put something in orbit around the Earth before you fire another

52:42 engine and fly it and fly it off to Mars or Jupyter or anything like that. They did not do that with New

52:47 Horizons. It was an Atlas V. It was overpowered. And it just shot as fast as it could to do a slingshot

52:53 off of Jupyter to get to Pluto. And it got there in 2015. I mean, Pluto at that point was a dwarf,

53:00 considered a dwarf planet. And it was supposed to be an ice ball. It's out in the middle of nowhere.

53:05 And the first photos that came back from New Horizons, there was a heart-shaped patch of red,

53:13 huge on the side of Pluto. It's all Tholans.

53:17 Oh, wow. It's this muddy stuff that you talked about.

53:21 Yeah. It's all, it doesn't cover the whole thing. I mean, it's very cold on Pluto. Make no mistake,

53:26 right? It's a very chilly place. Water ice is like rock. There are glaciers of methane and nitrogen. It

53:34 may even snow nitrogen there at times because it does have this oscillation in its orbit that it gets

53:40 closer to the sun when it's inside the orbit of Neptune and then gets colder as it was further away.

53:44 But you wouldn't, it had more texture and structure, young structures on it, you know,

53:51 maybe less than 100 million years old that indicated activity, a trans-Neptunian object,

53:58 like something so far, far away. And so again, it just sort of shook us up to this idea that

54:04 the ingredients for life tend to exist anywhere enough of it can gather to coalesce into a

54:10 structure. The, after it made the flyby of Pluto, because it was moving off as fast, it was only in

54:14 close to Pluto for a few days, they were able to do some tweaks and maneuvering to make a flyby of one

54:19 other trans-Neptunian object, which they've subsequently named Ultima Thule, which is actually two

54:24 rocks sort of sticking together, but it looks like it's entirely covered in Tholans.

54:31 Oh wow.

54:31 The whole thing is red.

54:32 Oh wow. How cool.

54:35 Yeah. So, you know, the byproduct of this is just this repeated sort of indication that

54:41 these things keep happening. The chemistry is always there, which brings up the interesting

54:45 question, which is why are there no Tholans on earth? You'd think, other than the Tholans we've

54:50 made ourselves, and the main reason is elemental oxygen. As soon as you introduce elemental oxygen,

54:55 it is going to rip apart all those Tholin compounds.

54:58 All right. It just wants to react straight away, huh?

55:00 Oxygen is greedy, right? Oxygen always finds a way to grab, you know, it'll, you mix oxygen in with

55:06 ammonia and you get nitro monoxide and water, right? You know, oxygen always gets in there.

55:13 So I think what we see in these Tholans are these early stages of life. And then as it advances,

55:19 they get destroyed to become resources as active oxygen is introduced to the system.

55:26 Right. Wow. So there's a lot of possibilities, a lot of places where this could be. A lot of it is

55:32 not obvious. It's underground or it's something, but especially those moons that sound really,

55:38 really interesting to me.

55:39 Yeah. And definitely a lot of energy around, can we make a mission, another mission to Enceladus

55:44 Enceladus and land on Enceladus? Yeah.

55:46 Maybe not actually bore through the ice the first try. The chances, you know,

55:49 I know they're doing experiments now in places like Antarctica to see, can we actually melt through the

55:54 ice kilometers? Because we don't have good enough measurements right now. Maybe we start with an

55:58 orbiter. The problem is the flight times are a decade. Like you pretty much commit to a lifetime.

56:03 So it takes you five to 10 years to build a mission, 10 years to get there and 10 years to operate

56:07 it. That's a career.

56:09 Yeah. That's just insane that the timescales needs to work on. And I think we'll probably be

56:13 coming back to that for a second here. But I think one of the things that's happening recently,

56:19 that's pretty interesting is what do we do if we want to have people go to other places?

56:26 Yeah.

56:26 So what we talked about so far is, you know, is there life around, you know, black smokers or

56:31 some other potential thing, or was there previously life on Venus? But there's some really wild ideas,

56:37 like maybe we could live on Venus, even though it's 90 times atmospheric pressure and it's 900 degrees

56:44 and whatnot.

56:45 So there's a spot on Venus that is almost one G and it's one atmosphere of pressure and it's 50

56:54 kilometers off the surface. So it's above the, for the most part, above the sulfuric acid clouds,

56:59 which is good. Although we can make sulfuric acid repellent materials.

57:02 It has a ton of solar power, about 40% more than earth. And it's atmosphere is so dense that you

57:08 could put a balloon filled with nitrox with breathable air in there big enough that you could

57:13 build a town in it. And it would simply sit on the, it would float on the atmosphere at that altitude.

57:18 So cover the top of it in solar panels. It's just that one atmosphere of pressure. If you get a hole

57:23 in it, it's not like the air rushes out. In fact, you probably make your sphere just slightly higher

57:28 pressure. So you, you tend to not to have the carbon dioxide come in, but you had the atmosphere

57:32 come up, but you could easily stitch it back up again. There was a concept mission developed called

57:37 HAVIC or the high altitude Venus operational concept using essentially blimps and rockets to go and explore

57:44 at that altitude around Venus. But one of the most interesting realizations was that the atmosphere

57:49 composition at that level has lots of carbon and oxygen, and even some hydrogen still, there's still some

57:54 water vapor at that level, lots of nitrogen, sulfur that, and it's all in gaseous form.

58:00 So if you want to live off the land, if you want to do in-situ resource utilization,

58:05 you just need a gas pump. You just pump the gases from the atmosphere in.

58:10 And then you typically, what you do is you chill it because each one of those compounds turns to a

58:15 liquid at different temperatures. So you literally are doing cryo-fractionation and you separate out each

58:21 of the fluids into the respective elements and then you use them in chemistry. You want to make

58:25 breathable air? No problem, right? You need to make some carbon structures? Yeah, we got those. No

58:32 problem. Like all of the compounds you need to take care of a lot of your consumables, they're there.

58:37 It's just that you're building a cloud city, which is weird. Like that's straight science fiction stuff

58:43 until you understand how dense... That is straight out of science fiction. Yeah.

58:47 Except the atmosphere is so dense, you don't have a buoyancy component. Your breathable air is buoyant.

58:54 And it's the only place where you'd be able to go outside without a pressure suit. Now you'd still be

58:59 wearing something because there's droplets of sulfuric acid, but it turns out Teflon repels sulfuric

59:04 has it just fine. So imagine wearing a body suit, Teflon coated, helmet on, you've got a respirator,

59:12 but you're not under a pressure. You're not inside a balloon like you are in a space suit.

59:17 So you can move very freely. It's going to be very bright. You have enough radiation protection

59:23 because there's enough magnetic field and there's enough atmosphere to protect you there. So it's

59:28 unique outside of the earth. One G, one bar of pressure, sufficient radiation protection,

59:34 ton of solar power. And some resources.

59:36 Yeah. And eventually you could build out the infrastructure to have enough resources to at

59:39 least keep yourself in water and air. Yeah.

59:41 It's more compelling than it ought to be.

59:43 That is such an insane idea, but it sounds actually better than living on the moon or living on Mars.

59:49 Well, because the moon's always going to be almost, I mean, not quite a camping trip,

59:53 but definitely an outpost. It's always going to need supplies.

59:56 Yeah. But you know, and Elon's keen to get to Mars because everybody can relate to Mars. You can see

01:00:03 its surface. It sort of has an environment to it. We've made movies about it, but the radiation

01:00:09 protection on Mars is simply not adequate. So, you know, all of those cartoony, science fiction-y,

01:00:16 we're going to build a city on Mars is not likely. We'll more likely build underground. There has been

01:00:22 enough volcanic activity over the millennia on Mars that there are significant lava tubes. So,

01:00:27 the pre-formed tunnels that you can put a pressurized habitat into. You are always going to have to wear a

01:00:33 pressure suit. The atmosphere is simply not strong enough. It's less than 1%. So, you're going to have

01:00:40 all of the spacesuit problems, which are not trivial. When you get into that low-pressure environment,

01:00:45 you have huge electrostatic problems. You have the perchlorates, which are an iodine compound that

01:00:51 we find in very desert-y areas on the earth as well. The Atacama Desert in Peru has perchlorates,

01:00:57 but perchlorates are everywhere on Mars. And they're quite bad for humans. They're quite a nasty contaminant.

01:01:02 They have to be chemically processed out, which is not energy cheap.

01:01:06 Right. Energy is expensive out there. You're far from the sun.

01:01:08 Yeah. Solar panels are not great there. We make them work on golf cart-sized machines. But as soon as you get

01:01:13 any bigger than that, the Curiosity rover is about the size of a mini, and it just couldn't be solar

01:01:17 powered. The solar panels would be too large. So, it has an RTG, a radiothermol generator on it. If

01:01:24 we're actually going to put humans on Mars, we're going to need nuclear power of some form. And there's

01:01:28 a bunch of interesting technologies around that that'll make it feasible. But the amount of solar

01:01:33 required, the dust problems and the electrostatic problems, it's just not efficient. It's even hard to

01:01:38 make solar work on the moon for the same reason. And you get a lot more solar power on the moon than you

01:01:43 do on Mars. But you're still talking less than a kilowatt per square meter on the moon. And you're

01:01:50 talking half that on Mars and maintenance. It's just not enough power. So, you know, although you

01:01:58 get double at Venus, so you have more options there. And you don't have the atmospheric problems.

01:02:03 You're still going to need to do some maintenance because they're going to have to resist sulfuric acid

01:02:07 and things like that. But it certainly has more possibility. Heat will be a challenge.

01:02:11 But none of these planets is going to be...

01:02:14 If you build a starship, would you go? Would you take a trip?

01:02:18 Oh, yeah. But I'd want to come back. I'll take a ride for sure. You know, I don't have the money for

01:02:23 the current generation of space explorers. But, you know, the side effect of when starship works,

01:02:29 it's not going to be the trip to Mars. It's going to be interesting. It's going to be orbital hotels.

01:02:33 Yeah.

01:02:34 Because they suddenly get way more feasible. Now it's like, I could buy a house or spend a week or

01:02:38 two in orbit. And that's... I'd be tempted, you know. Got a house. Raised my kids. I'm happy to

01:02:45 spend their inheritance at this point.

01:02:47 It would be like a really different cruise.

01:02:50 Yeah. Really extraordinary cruise. I mean, very, very expensive. But, you know,

01:02:55 this may well be coming in our lifetime. Especially, I mean, a star... Starship is going to take longer

01:03:01 than Elon plans, but then everything Elon plans take longer than Elon plans. But his design seems

01:03:07 essentially sound. And if he has a 100% reusable spacecraft so that we're only paying for fuel,

01:03:13 now we're talking pennies a kilo into orbit instead of hundreds of... I mean, he's gotten...

01:03:20 Even Falcon 9 is below $2,000 a kilo to orbit, which is astonishing. Like, it's a revelation. It is

01:03:26 literally an order of magnitude improvement. Yeah.

01:03:29 But starship would be three more orders of magnitude. Like, now 20 cents a kilo, like that.

01:03:34 That is insane.

01:03:35 You're in the ballpark. Yeah. Well, I mean, if anyone's going to do it, that guy's going to do it. He's got some... Well, don't count Bezos out. The only reason,

01:03:43 you know, Elon is a showman for a reason. He needs money. Now, he's mostly showing off to his

01:03:50 billionaire friends, right? It's Sergey and Larry that are funding him a lot of the time. But Jeff

01:03:56 doesn't need the money, which is why he sort of keeps it to himself. Yeah.

01:04:01 I think we may get surprised by him that New Glenn is further along than we realize.

01:04:05 And that is one heck of a rocket design. And it'll obviously be different than what's known

01:04:10 because he keeps himself close to the chest. But his mission is not to put humans on Mars.

01:04:15 He's much more in the O'Neill cylinder category. He'd like to build habit, learn how to mine asteroids,

01:04:21 build structures in space, and build 1G habitats. Gravity wells are dumb. Like, why would you go back

01:04:28 down into a gravity well and make it expensive to get flying around when I can hollow out an

01:04:34 asteroid, put some artificial light in the center of it, spin it up so that you have 1G, and fill it

01:04:42 full of people and wildlife and resources. And anytime you want to go back into space, you take

01:04:47 an elevator to the center where there's no gravity again and out to a non-rotating rim where you can

01:04:53 hop in a spacecraft and take off. Now, that's a tremendous amount of technology. That's probably

01:04:58 decades worth of work. But it starts with being able to get into orbit cheaply.

01:05:03 Yeah, absolutely it does. How interesting. All right, let's wrap this up. We're getting short on time.

01:05:07 Sure.

01:05:08 Bring it back to the beginning. So, we talked about Drake's equation, which puts a bunch of

01:05:14 probabilities together. Almost any non-zero number you put in there, knowing how many stars are in a

01:05:21 galaxy and how many galaxies there are, shoots out a tremendous number of potential habitable places

01:05:27 with life forms. And yet, there's Fermi's paradox.

01:05:31 Yeah. Where are they?

01:05:33 Where are they? I mean, we're finding all these exoplanets. What do you think? What is your gut feeling

01:05:37 here? I think that the ingredients for life are super common, but the conditions are more challenging.

01:05:46 How do we get a planet with a strong magnetic field? So, it has an oversized moon. These days,

01:05:52 we talk more and more about the chemistry of the moon's lower core, that it's not just the nickel iron

01:05:59 that's compressed in the center. But also, there are tendrils of spirals of sulfur coming out of them that

01:06:05 help amplify that magnetic field. So, it may be that there's only particular windows of time in the

01:06:12 evolution of a planet where it actually makes a magnetic field strong enough to really defend its

01:06:17 atmosphere. And hopefully, it has enough atmosphere to defend at that point. But then, also, it's cooled down

01:06:23 enough that the floating pieces of land that create land masses don't float so freely that they're just

01:06:30 one big land mass so that you have a homogeneous life on it, but rather start to stick to each other and

01:06:37 break apart and become and create plate tectonics that then distribute.

01:06:41 Create these currents that level out the atmospheric and weather patterns and all that, right?

01:06:46 But also, create conditions for rapid evolution. What happens when you fragment the land mass up is

01:06:52 you create micro environments for evolution. You know, we wouldn't have kangaroos and all of those

01:07:00 weird monotremes if not for the isolation that is Australia. And so, how do you create conditions

01:07:07 where different things can evolve and then encounter themselves later? And I think continental

01:07:13 drift is an important part of it. So, you need a planet that is hot enough and energetic enough

01:07:17 that it's making a strong and athletic field, but cool enough that its plate tectonics exist and are

01:07:22 fracturing land to create that petri dish of evolution. Like, now you're starting to get into tougher numbers.

01:07:29 Yeah, it's getting smaller.

01:07:31 And then throw into that little indicator I threw at the beginning, which is when you finally evolve

01:07:36 a tool building life that starts developing technology and they go up that hockey stick

01:07:41 of technological advancement. How long before they wink out of existence as far as we're concerned,

01:07:47 either by destroying themselves or by evolving beyond this universe?

01:07:50 Yeah. And the other thing that comes back for me all the time is you talked about,

01:07:55 let's just go visit, what was it, Pluto? If we do it at the right time, it'll only take 10 years of flight

01:08:03 time. If we do it the wrong time, it'll take 50 years of flight time.

01:08:06 Or never.

01:08:07 And that's just within the solar space.

01:08:08 Yeah.

01:08:09 Space is so big that I think it breaks our conception. Like, oh yeah, there's a billion of them over there,

01:08:16 but they happen to be so far away that it's inconceivably far. There's no,

01:08:20 the thought of going there doesn't make sense. Like generations won't, you know,

01:08:25 how many generations do you need to get there?

01:08:27 But let me throw you a wrench into those numbers for you. We use chemical rockets right now,

01:08:31 where they, which burn very brightly, very briefly. There are better rocket engines.

01:08:37 And not that I know that we have the answer to this, but we have a few good ideas about better engines,

01:08:41 nuclear engines being one example of it. But imagine at the right period, right? This is certain

01:08:48 moments where it makes sense to fly between the earth and Mars. So I picked the right moment to fly

01:08:52 between the earth and Mars. But I have a very special spacecraft. I have a spacecraft that can

01:08:55 accelerate at exactly one G. Okay. So it's like normal earth gravity. The engine runs continuously.

01:09:03 So I'm going to burn continuously at one G of acceleration towards Mars. So we get about halfway.

01:09:08 Then I'm going to turn around and I'm going to burn at one G to decelerate so that we arrive at Mars.

01:09:13 How long did it take me to go from the earth to Mars at one G of continuous acceleration, deceleration?

01:09:18 One G. Yeah. How long does it take now? 18 months?

01:09:22 Yeah. Four to six months, depending on a bunch of factors. I don't need you to do the math,

01:09:26 friend. I'll just tell you. I think I'm going to say one month.

01:09:28 It's three days. Oh, okay.

01:09:30 So this is the, and so you can imagine if we could sand two Gs, it'll be a day and a half. Given we can

01:09:37 put smart people in space and create incentives to actually fly between bodies on a routine basis,

01:09:42 we can make better engines. We can make the solar system far more approachable.

01:09:47 We have not needed to. Every engine we've ever flown in space, we built on earth. And first,

01:09:54 it had to survive being put into orbit and then operated. When we start building vehicles in space

01:10:01 for space, they will be very different and they will have new capabilities. We will learn to do things

01:10:07 with the different resources we have available to you. We built spacecraft out of aluminum because we

01:10:11 have to lift them into orbit. It makes no sense to do that once you're in space.

01:10:16 It's just metal that melts really easily.

01:10:18 Yeah. It has a whole ton of problems and it's not that common. You know what would be easier to find?

01:10:23 Nickel iron. They make asteroids out of this stuff. You know, maybe a true spacecraft built in space will

01:10:31 be made from a nickel iron hull. It'll be heavier, but it won't matter. You know, we are not there yet.

01:10:38 We're starting to get the ingredients to start thinking in terms of more powerful engines and

01:10:43 vehicles built for interplanetary flight. We can do much better. We just haven't needed to yet. We will,

01:10:51 we're not there yet. Well, I think we probably will. You're right. I mean, 400 years ago, we used wind and

01:10:57 sails on the water. Yeah. And still we coveted rare, rare kinds of woods like iron wood from the Indies,

01:11:05 you know, for mass. Like they, you know, one of the claims to fame for the Americans was their American

01:11:11 Oak made incredible hulls that we came up with a technique that they built the constitution with old

01:11:17 iron sides. Well, there's no iron on the old iron sides. It's wood. Like there is abilities as you

01:11:23 start functioning that space to get better at it. We just never done it because we have not had people

01:11:29 building in space yet. The moment we do things will happen.

01:11:33 Yeah. Well, that sounds very exciting. It's been really fun to explore this whole idea of,

01:11:38 you know, life in the universe. Where is it? Where could it be? And beyond. So yeah,

01:11:43 Richard, thanks for coming back on the show. Well, my pleasure, friend. I will do this with

01:11:46 you anytime you like. It's a, it's an excuse for me to sit down and update all that research,

01:11:51 right? To say, okay, all the notes I've taken over the past couple of years, since the last time we sort

01:11:55 of dug into this, what have we learned? And I'm always in, I come out of it always excited. Like,

01:11:59 I can't believe how much we've learned in this short amount of time. If you just stop and take

01:12:03 in everything that's going on, it's such an exciting time. It is. The civilization is at,

01:12:08 is doing amazing things right now. We have non-trivial challenges and we could have spoken

01:12:14 for an hour on coronavirus. I don't let anybody want to listen to it, but we could have, because

01:12:19 again, we are doing remarkable things there as well. Some less remarkable also, but it's never

01:12:26 been a bad finder time to be alive. It doesn't feel like it's at times, but truly we're at the

01:12:31 height of our civilization right now. I agree. I think the, there's some rough times,

01:12:34 times, but I think there are bumps in the road. Well, and so much more to do. Like if you thought

01:12:38 we've, you know, okay, we've done everything. We're good. No, there's more to do.

01:12:42 Not even close. All right. Well, thanks so much for being on the show. It's great to chat with you as

01:12:46 always.

01:12:46 You bet, brother. Thank you.

01:12:47 Bye.

01:12:48 Bye.

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