Katherine de Kleer: Planets, Moons, Asteroids & Life in Our Solar System

00:00:00.000 | The following is a conversation with Catherine DeCleer,

00:00:02.540 | a professor of planetary science and astronomy at Caltech.

00:00:06.640 | Her research is on the surface environments,

00:00:09.320 | atmospheres, and thermochemical histories

00:00:12.600 | of the planets and moons in our solar system.

00:00:15.880 | Quick mention of our sponsors,

00:00:17.600 | Fundrise, Blinkist, ExpressVPN, and Magic Spoon.

00:00:22.600 | Check them out in the description to support this podcast.

00:00:25.760 | As a side note, let me say that this conversation

00:00:28.200 | and a few others, quite big ones actually,

00:00:30.840 | that are coming up were filmed in a studio

00:00:33.280 | where I was trying to outsource some of the work.

00:00:35.980 | Like all experiments, it was a learning experience for me.

00:00:38.800 | It had some positives and negatives.

00:00:40.920 | Ultimately, I decided to return back to doing it

00:00:43.000 | the way I was doing before,

00:00:44.040 | but hopefully with a team who can help me out

00:00:47.320 | and work with me long-term.

00:00:49.500 | The point is I will always keep challenging myself,

00:00:52.320 | trying stuff out, learning, growing,

00:00:54.440 | and hopefully improving over time.

00:00:56.540 | My goal is to surround myself with people

00:00:58.680 | who love what they do, are amazing at it,

00:01:01.480 | and are obsessed with doing the best work of their lives.

00:01:04.880 | To me, there's nothing more energizing and fun than that.

00:01:08.000 | In fact, I'm currently hiring a few folks

00:01:10.420 | to work with me on very small projects.

00:01:12.540 | If this is something of interest to you,

00:01:14.800 | go to lexfriedman.com/hiring.

00:01:17.340 | That's where I will always post opportunities

00:01:19.580 | for working with me.

00:01:21.480 | This is the Lex Friedman Podcast,

00:01:23.640 | and here is my conversation with Catherine DeCleer.

00:01:26.780 | Why is Pluto not a planet anymore?

00:01:30.020 | Does this upset you, or has justice finally been served?

00:01:34.300 | - So I get asked this all the time.

00:01:38.300 | I think all planetary scientists get asked about Pluto,

00:01:41.460 | especially by kids who would just love for Pluto

00:01:44.220 | to still be a planet.

00:01:45.320 | But the reality is when we first discovered Pluto,

00:01:51.860 | it was a unique object in the outer solar system,

00:01:54.380 | and we thought we were adding a planet

00:01:57.060 | to the inventory of planets that we had.

00:01:58.940 | And then over time, it became clear that Pluto

00:02:01.660 | was not a unique large object in the outer solar system,

00:02:05.740 | that there were actually many of these.

00:02:07.920 | And as we started discovering more and more of them,

00:02:10.820 | we realized that the concept of Pluto being a planet

00:02:13.540 | didn't make sense unless maybe we added

00:02:17.680 | all the rest of them as planets.

00:02:18.900 | So you could have imagined actually a different direction

00:02:21.260 | that this could have gone, where all the other objects

00:02:24.060 | that were discovered in that belt,

00:02:25.620 | or at least all the ones, let's say, above a certain size,

00:02:28.980 | became planets instead of Pluto being declassified.

00:02:32.160 | But we're now aware of many objects out there

00:02:36.400 | in the outer solar system, in what's called the Kuiper Belt,

00:02:38.780 | that are of the same size, or in some cases,

00:02:41.740 | even larger than Pluto.

00:02:43.180 | So the declassification was really just a realization

00:02:47.740 | that it was not in the same category

00:02:50.700 | as the other planets in the solar system,

00:02:52.620 | and we basically needed to refine our definition

00:02:55.800 | in such a way that took into account

00:02:57.380 | that there's this belt of debris out there

00:03:01.460 | in the outer solar system of things with a range of sizes.

00:03:05.020 | - Is there a hope for clear categorization

00:03:07.900 | of what is a planet and not?

00:03:10.140 | Or is it all just gray area?

00:03:11.780 | When you study planets, when you study moons,

00:03:13.860 | satellites of those planets,

00:03:15.620 | is there lines that could be cleanly drawn,

00:03:19.380 | or is it just a giant mess?

00:03:21.380 | Is this all like a fluid, let's say not mess,

00:03:23.940 | but it's like fluid of what is a planet,

00:03:27.020 | what is a moon of a planet, what is debris,

00:03:29.620 | what is asteroids, all that kind of?

00:03:32.460 | - So there are technically clear definitions

00:03:35.220 | that were set down by the IAU,

00:03:37.260 | the International Astronomy Union.

00:03:39.820 | - Is it size-related?

00:03:42.900 | Like what are the parameters based on what?

00:03:44.500 | - So the parameters are that it has to orbit the sun,

00:03:47.460 | which was essentially to rule out satellites.

00:03:49.740 | Of course, this was a not very forward-thinking definition

00:03:52.700 | because it technically means that all extrasolar planets,

00:03:55.140 | according to that definition, are not planets.

00:03:57.960 | So it has to orbit the sun.

00:04:00.300 | It has to be large enough that its gravity

00:04:02.500 | has caused it to become spherical in shape,

00:04:05.380 | which also applies to satellites and also applies to Pluto.

00:04:08.260 | The third part of the definition

00:04:09.900 | is the thing that really rules out everything else,

00:04:11.620 | which is that it has to have cleared out its orbital path.

00:04:15.420 | And because Pluto orbits in a belt of material,

00:04:18.500 | it doesn't satisfy that stipulation.

00:04:21.460 | - Why didn't it clear out the path?

00:04:22.820 | It's not big enough to knock everybody out of the way?

00:04:25.500 | - And this actually is not the first time it has happened.

00:04:28.980 | So Ceres, when it was discovered,

00:04:30.980 | Ceres is the largest asteroid in the asteroid belt,

00:04:33.140 | and it was originally considered a planet

00:04:35.440 | when it was first discovered.

00:04:36.680 | And it went through exactly the same story, history,

00:04:40.980 | where people actually realized

00:04:42.860 | that it was just one of many asteroids

00:04:44.700 | in the asteroid belt region,

00:04:45.900 | and then it got declassified to an asteroid,

00:04:48.060 | and now it's back to a dwarf planet.

00:04:50.100 | So there is a lot of reclassification.

00:04:52.020 | So to me, as somebody who studies solar system objects,

00:04:56.540 | I just personally don't care.

00:04:59.780 | My level of interest in something has nothing to do

00:05:02.220 | with what it's classified as.

00:05:04.380 | So my favorite objects in the solar system are all moons,

00:05:07.100 | and frequently when I talk about them,

00:05:08.900 | I refer to them as planets,

00:05:10.100 | because to me they are planets.

00:05:12.340 | They have volcanoes, they have geology,

00:05:14.220 | they have atmospheres, they're planet-like worlds.

00:05:17.020 | And so the distinction is not super meaningful to me,

00:05:20.020 | but it is important just for having a general framework

00:05:23.980 | for understanding and talking about things

00:05:27.160 | to have a precise definition.

00:05:28.700 | - So you don't have a special romantic appreciation

00:05:32.220 | of a moon versus a planet versus an asteroid.

00:05:34.540 | It's just an object that flies out there,

00:05:36.260 | and it doesn't really matter what the categorization is.

00:05:39.100 | Because there's movies about asteroids and stuff.

00:05:41.260 | And then there's movies about the moon,

00:05:45.220 | whatever, it's a really good movie.

00:05:46.980 | There's something about moons

00:05:50.180 | that's almost like an outlier.

00:05:55.460 | You think of a moon as a thing that's the secret part,

00:06:00.460 | and the planet is the more vanilla, regular part.

00:06:05.380 | None of that?

00:06:06.220 | You don't have any of that?

00:06:07.040 | - No, I actually do.

00:06:07.880 | Really, satellites, the moons are my favorite things

00:06:10.460 | in the solar system.

00:06:11.300 | And I think part of what you're saying,

00:06:13.340 | I agree from maybe a slightly different perspective,

00:06:17.260 | which is from the perspective of exploration.

00:06:19.480 | We've spent a lot of time

00:06:20.960 | sending spacecraft missions to planets.

00:06:23.680 | We had a mission to Jupiter, we had a mission to Saturn.

00:06:25.780 | We have plenty of missions to Mars and missions to Venus.

00:06:28.560 | I think the exploration of the moons

00:06:30.600 | in the outer solar system is the next frontier

00:06:33.160 | of solar system exploration.

00:06:35.300 | - The belt of debris, just real quick.

00:06:37.820 | That's out there.

00:06:39.300 | Is there something incredible to be discovered there?

00:06:42.480 | Again, we tend to focus on the planets and the moons,

00:06:45.340 | but it feels like there's probably a lot of stuff out there.

00:06:49.140 | And it probably, what is it?

00:06:51.760 | It's like a garbage collector

00:06:53.120 | from outside of the solar system, isn't it?

00:06:56.700 | Like, doesn't it protect from other objects

00:06:59.140 | that kind of fly in?

00:07:00.100 | And what, it just feels like it's a cool,

00:07:03.460 | you know when you like walk along the beach

00:07:06.980 | and look for stuff and like look for,

00:07:08.980 | it feels like that's that kind of place

00:07:11.180 | where you can find cool, weird things.

00:07:13.740 | Or I guess in our conversation today,

00:07:16.820 | when we think about tools and what science is studying,

00:07:20.460 | is there something to be studied out there?

00:07:22.380 | Or we just don't have maybe the tools yet,

00:07:24.180 | or there's nothing to be found?

00:07:26.260 | - There's absolutely a lot to be found.

00:07:28.300 | So the material that's out there is remnant material

00:07:30.560 | from the formation of our solar system.

00:07:32.420 | We don't think it comes from outside the solar system,

00:07:34.820 | at least not most of it.

00:07:37.380 | But there are so many fascinating objects out there.

00:07:42.380 | And I think what you've hit on is exactly right,

00:07:45.060 | that we just don't have the tools to study them in detail.

00:07:48.720 | But we can look out there and we can see

00:07:50.820 | there are different species of ice on their surface

00:07:53.220 | that tells us about, you know, the chemical composition

00:07:56.660 | of the disk that formed our solar system.

00:07:58.900 | Some of these objects are way brighter than they should be,

00:08:01.580 | meaning they have some kind of geological activity.

00:08:04.120 | People have hypothesized that some of these objects

00:08:06.300 | have subsurface oceans.

00:08:07.940 | You could even stretch your imagination

00:08:09.620 | and say some of those oceans could be habitable.

00:08:12.360 | But we can't get very detailed information about them

00:08:15.840 | because they're so far away.

00:08:16.920 | And so I think if any of those objects

00:08:19.300 | were in the inner solar system,

00:08:20.520 | it would be studied intently and would be very interesting.

00:08:23.940 | - So would you be able to design a probe

00:08:26.820 | in that like very dense debris field,

00:08:29.840 | be able to like hop from one place to another?

00:08:32.700 | Is that just outside of the realm of,

00:08:35.060 | like how would you even design devices

00:08:37.420 | or sensors that go out there and take pictures and land?

00:08:42.180 | Do you have to land to truly understand

00:08:44.580 | a little piece of rock?

00:08:46.460 | Or can you understand it from remotely,

00:08:48.220 | like fly up close and remotely observe?

00:08:51.320 | - You can learn quite a lot from just a flyby

00:08:55.260 | and that's all we're currently capable of doing

00:08:57.060 | in the outer solar system.

00:08:58.540 | The New Horizons mission is a recent example

00:09:01.900 | which flew by Pluto.

00:09:03.060 | And then they had searched for another object

00:09:06.540 | that was out there in the Kuiper belt,

00:09:07.900 | any object that was basically somewhere

00:09:10.540 | that they could deflect their trajectory to actually fly by.

00:09:13.860 | And so they did fly by another object

00:09:16.180 | out there in the Kuiper belt and they take pictures

00:09:18.620 | and they do what they can do.

00:09:19.620 | And if you've seen the images from that mission of Pluto,

00:09:22.660 | you can see just how much detail we have

00:09:25.780 | compared to just the sort of reddish dot

00:09:27.820 | that we knew of before.

00:09:29.620 | So you do get an amazing amount of information actually

00:09:32.460 | from just essentially a high-speed flyby.

00:09:35.380 | - It always makes me sad to think about flybys

00:09:38.020 | that we might be able to,

00:09:39.620 | we might fly by a piece of rock, take a picture

00:09:43.940 | and think, oh, that looks pretty and cool and whatever.

00:09:45.980 | And that you could study certain like composition

00:09:48.180 | of the surface and so on.

00:09:49.700 | But it's actually teeming with life

00:09:52.180 | and we won't be able to see it at first.

00:09:55.620 | And it's sad 'cause you know,

00:09:57.620 | like when you're on a deserted island,

00:09:58.900 | you wave your hands and the thing flies by

00:10:01.140 | and you're trying to get their attention

00:10:03.420 | and they probably do the same, well, in their own way.

00:10:06.500 | Bacteria probably, right?

00:10:07.780 | But, and we miss it.

00:10:10.260 | I don't know, some reason it makes me,

00:10:12.260 | it's the FOMO, it's fear of missing out.

00:10:15.040 | It makes me sad that there might be life out there

00:10:18.900 | and we don't, we're not in touch with it.

00:10:23.500 | We're not talking.

00:10:24.440 | Yeah.

00:10:26.340 | Well, okay.

00:10:28.980 | A sad pause, Russian philosophical pause.

00:10:32.460 | Okay, what are the tools available to us

00:10:34.700 | to study planets and their moons?

00:10:36.700 | Oh my goodness, that is such a big question.

00:10:40.400 | So among the fields of astronomy,

00:10:44.260 | so planetary science broadly speaking,

00:10:46.500 | well, it falls kind of at the border of astronomy,

00:10:50.380 | geology, climate science, chemistry, and even biology.

00:10:53.840 | So it's kind of on the border of many things,

00:10:55.500 | but part of it falls under the heading of astronomy.

00:10:58.460 | And among the things that you can study with telescopes,

00:11:01.420 | like solar system moons and planets,

00:11:04.580 | the solar system is really unique

00:11:06.180 | in that we can actually send spacecraft missions

00:11:09.460 | to the objects and study them in detail.

00:11:11.540 | And so I think that's the kind of type of tool

00:11:14.300 | that people are most aware of,

00:11:16.140 | that's most popularized, these amazing NASA missions

00:11:19.660 | that either you fly by the object, you orbit the object,

00:11:23.500 | you land on the object,

00:11:24.740 | potentially you can talk about digging into it,

00:11:28.140 | drilling, trying to detect tectonic tremors on its surface.

00:11:33.140 | The types of tools that I use are primarily telescopes.

00:11:38.900 | And so my background is in astrophysics.

00:11:42.300 | And so I actually got into solar system science

00:11:44.560 | from astronomy, not from a childhood fascination

00:11:48.380 | with spacecraft missions,

00:11:49.340 | which is actually what a lot of planetary scientists

00:11:52.380 | became planetary scientists

00:11:53.660 | because of childhood fascination with spacecraft missions,

00:11:56.320 | which is kind of interesting for me to talk to people

00:11:59.500 | and see that trajectory.

00:12:00.500 | I kind of came at it from the fascination

00:12:02.380 | with telescopes angle.

00:12:03.700 | - So you like telescopes, not rockets, or at least you--

00:12:06.340 | - When I was a kid, it was looking at the stars

00:12:09.280 | and playing with telescopes that really fascinated me.

00:12:11.680 | And that's how I got into this.

00:12:14.020 | But telescopes, it's amazing how much detail

00:12:18.900 | and how much information you can get from telescopes today.

00:12:22.640 | You can resolve individual cloud features

00:12:27.200 | and watch them kind of sheer out

00:12:29.060 | in the atmosphere of Titan.

00:12:30.620 | You can literally watch volcanoes on Io change

00:12:34.540 | from day to day as the lava flows expand.

00:12:37.380 | So, and then, you know, with spectroscopy,

00:12:41.320 | you get compositional information on all these things.

00:12:43.600 | And it's, when I started doing solar system astronomy,

00:12:48.600 | I was surprised by how much detail

00:12:51.180 | and how much information you can get even from Earth.

00:12:54.220 | And then, as well as from orbit,

00:12:55.820 | like the Hubble Space Telescope or the James Webb.

00:12:58.320 | - So with a telescope, you can, I mean,

00:13:03.380 | how much information can you get about volcanoes,

00:13:06.420 | about storms, about sort of weather,

00:13:10.020 | just so we kind of get a sense,

00:13:12.760 | like what a resolution we're talking about?

00:13:15.340 | - Well, in terms of resolution, so at a, you know,

00:13:18.500 | on a given night, if I go and take a picture of Io

00:13:20.920 | and its volcanoes, you can sometimes see

00:13:23.180 | at least a dozen different volcanoes.

00:13:26.420 | You can see the infrared emission coming off of them

00:13:28.400 | and resolve them, separate them from one another

00:13:31.460 | on the surface and actually watch how the heat coming off

00:13:35.220 | of them changes with time.

00:13:37.420 | And I think this time variability aspect

00:13:39.380 | is one of the big advantages we get from telescopes.

00:13:41.740 | So you send a spacecraft mission there

00:13:43.740 | and you get an incredible amount of information

00:13:45.980 | over a very short time period.

00:13:47.540 | But for some science questions,

00:13:49.460 | you need to observe something for 30 years, 40 years.

00:13:53.440 | Like let's say you want to look at the moon Titan,

00:13:56.120 | which has one of the most interesting atmospheres

00:13:58.660 | in the solar system.

00:14:00.360 | Its orbital period is 29, 30 years.

00:14:04.560 | And so if you want to look at how

00:14:07.080 | its atmospheric seasons work,

00:14:08.720 | you have to observe it over that long of a time period.

00:14:11.200 | And you're not going to do that with a spacecraft,

00:14:13.240 | but you can do it with telescopes.

00:14:15.360 | - Can we just zoom in on certain things?

00:14:17.540 | Like let's talk about Io, which is the moon of Jupiter.

00:14:21.740 | - Right.

00:14:22.580 | - Okay, it's like epic.

00:14:23.920 | There's like volcanoes all over the place.

00:14:27.200 | It's from a distance, it's awesome.

00:14:30.960 | So can you tell me about this moon

00:14:33.000 | and you're sort of a scholar of many planets and moons,

00:14:37.600 | but that one kind of stood out to me.

00:14:40.080 | So why is that an interesting one?

00:14:42.280 | - For so many reasons,

00:14:43.600 | but Io is the most volcanically active object

00:14:46.920 | in the solar system.

00:14:47.760 | It has hundreds of active volcanoes on it.

00:14:50.440 | It has volcanic plumes that go hundreds of kilometers

00:14:54.520 | up above its surface.

00:14:56.040 | It puts out more volume of magma per volcano

00:14:59.600 | than volcanoes on earth today.

00:15:03.040 | But I think to me, the reason that it's most interesting

00:15:07.360 | is as a laboratory for understanding planetary processes.

00:15:12.360 | So one of the broad goals of planetary science

00:15:15.720 | is to put together a sort of more general

00:15:18.840 | and coherent framework for how planets work in general.

00:15:23.840 | Our current framework, it started out very earth centric.

00:15:27.640 | We start to understand how earth volcanoes work.

00:15:30.480 | But then when you try to transport that

00:15:32.520 | to somewhere like Io that doesn't have an atmosphere,

00:15:35.120 | which makes it has a very tenuous atmosphere,

00:15:37.820 | which makes a big difference for how the magma degasses.

00:15:41.480 | For something that's really small,

00:15:42.800 | for something that has a different heat source,

00:15:44.600 | for something that's embedded in another object's

00:15:46.640 | magnetic field, the kind of intuition we have from earth

00:15:49.460 | doesn't apply.

00:15:50.300 | And so broadly, planetary sciences is trying to broaden

00:15:55.060 | that framework so that you have a kind of narrative

00:15:57.640 | that all you can understand how each planet

00:16:00.000 | became different from every other planet.

00:16:02.440 | And I'm already making a mistake.

00:16:04.040 | When I say planet, I mean planets and moons.

00:16:06.240 | Like I said, I see the moons as planets.

00:16:08.280 | - As planets.

00:16:09.360 | Yeah, I actually already noticed that you didn't introduce

00:16:12.320 | Io as the moon of Jupiter.

00:16:14.520 | You completely, you kind of ignored the fact

00:16:18.320 | that Jupiter exists.

00:16:19.400 | It's like, let's focus on the...

00:16:21.000 | Yeah, okay, so and you also didn't mention Europa,

00:16:26.560 | which I think is the,

00:16:27.400 | is that the most famous moon of Jupiter?

00:16:29.720 | Is that the one that gets attention

00:16:32.360 | 'cause it might have life?

00:16:33.320 | - Exactly, yeah.

00:16:34.720 | - But to you, Io is also beautiful.

00:16:37.760 | What's the difference between volcanoes on Io versus earth?

00:16:42.240 | You said atmosphere makes a difference.

00:16:44.680 | What-- - Yeah.

00:16:46.240 | The heat source plays a big role.

00:16:48.440 | So many of the moons in the outer solar system

00:16:52.140 | are heated from gravitationally by tidal heating.

00:16:55.440 | And I'm happy to describe what that is or not.

00:16:58.640 | - Well, yeah, please, what's tidal?

00:17:00.680 | Yes, yes, please. - So tidal heating is,

00:17:03.000 | if you wanna understand and contextualize planets and moons,

00:17:07.740 | you have to understand their heat sources.

00:17:10.520 | So for earth, we have radioactive decay in our interior,

00:17:14.080 | as well as residual heat of formation.

00:17:16.320 | But for satellites,

00:17:18.320 | tidal heating plays a really significant role,

00:17:20.560 | and in particular,

00:17:21.500 | in driving geological activity on satellites

00:17:24.160 | and potentially making those subsurface oceans

00:17:27.480 | in places like Europa and Enceladus habitable.

00:17:30.640 | And so the way that that works is

00:17:32.920 | if you have multiple moons

00:17:34.640 | and their orbital periods

00:17:37.280 | are integer multiples of one another,

00:17:39.520 | that means that they're always encountering each other

00:17:42.560 | at the same point in the orbit.

00:17:45.060 | So if they were on just random orbits,

00:17:48.360 | they'd be encountering each other at random places,

00:17:50.320 | and the gravitational effect between the two moons

00:17:52.680 | would be canceling out over time.

00:17:54.920 | But because they're always meeting each other

00:17:56.780 | at the same point in the orbit,

00:17:59.120 | those gravitational interactions add up coherently.

00:18:02.320 | And so that tweaks them into eccentric orbits.

00:18:06.640 | - What's an eccentric orbit?

00:18:07.920 | - So eccentric orbit or elliptical orbit,

00:18:10.440 | it just means non-circular,

00:18:12.020 | so a deviation from a circular orbit.

00:18:13.880 | And that means that for Io or Europa,

00:18:16.800 | at some points in their orbit,

00:18:18.200 | they're closer to Jupiter,

00:18:19.400 | and at some points in their orbit, they're farther away.

00:18:22.240 | And so when they're closer,

00:18:24.280 | they're stretched out in a sense,

00:18:27.840 | but literally just not very stretched out,

00:18:30.300 | like a couple hundred meters, something like that.

00:18:32.000 | And then when they're farthest away,

00:18:34.000 | they're less stretched out.

00:18:35.280 | And so you actually have the shape of the object

00:18:38.040 | deforming over the course of the orbit.

00:18:40.080 | And these orbits are like just a couple of days.

00:18:42.320 | And so that, in the case of Io,

00:18:44.600 | that is literally sufficient friction in its mantle

00:18:48.760 | to melt the rock of its mantle.

00:18:50.720 | And that's what generates the magma.

00:18:52.600 | - That's the source of the magma.

00:18:55.200 | Okay, so why is, so Europa is,

00:18:59.160 | I thought there was like ice

00:19:00.920 | and oceans underneath kind of thing.

00:19:03.080 | So why is Europa not getting the friction?

00:19:05.240 | - It is, it's just a little bit farther away from Jupiter.

00:19:07.720 | And then Ganymede is also in the orbital resonance.

00:19:10.680 | So it's a three object orbital resonance

00:19:13.040 | in the Jupiter system.

00:19:14.680 | But we have these sorts of orbital resonances

00:19:17.220 | all over the solar system and also in exoplanets.

00:19:20.600 | So for Europa, basically because it's farther from Jupiter,

00:19:24.040 | the effect is not as extreme,

00:19:25.560 | but you do still have heat generated in its interior

00:19:28.800 | in this way, and that may be driving,

00:19:31.480 | could be driving hydrothermal activity

00:19:33.400 | at the base of its ocean,

00:19:34.880 | which obviously would be a really valuable thing for life.

00:19:38.600 | - Cool, so it's like heating up the ocean a little bit.

00:19:41.880 | - Heating up the ocean a little bit.

00:19:43.280 | And specifically in these like hydrothermal vents

00:19:46.240 | where we see really interesting life evolve

00:19:49.320 | in the bottom of Earth's oceans.

00:19:51.160 | - That's cool, okay.

00:19:52.080 | So what's Io, what else?

00:19:55.440 | So we know the source is this friction,

00:19:58.060 | but there's no atmosphere.

00:19:59.840 | I'm trying to get a sense of what it's like

00:20:01.400 | if you and I were to visit Io.

00:20:04.200 | What would that look like?

00:20:06.480 | What would it feel like?

00:20:07.680 | Is this the entire thing covered in basically volcanoes?

00:20:13.720 | - So it's interesting because there's very little atmosphere.

00:20:18.640 | The surface is actually really cold,

00:20:20.920 | very far below freezing on the surface

00:20:22.960 | when you're away from a volcano,

00:20:24.320 | but the volcanoes themselves are over a thousand degrees

00:20:27.800 | or the magma when it comes out is over a thousand degrees.

00:20:30.720 | So--

00:20:31.800 | - But it does come to the surface, the magma?

00:20:33.760 | - It does, yeah.

00:20:34.680 | - In particular places.

00:20:37.440 | Whoa, that probably looks beautiful.

00:20:39.040 | So like, so it's frozen, not ice.

00:20:42.400 | Like what is rock?

00:20:44.560 | It's really cold rock.

00:20:46.260 | And then you just have this like,

00:20:48.440 | what would that look like with no atmosphere?

00:20:53.360 | Would that, would it be smoke?

00:20:55.820 | What does it look like?

00:20:58.520 | Is just magma, like just red, yellow, like liquidy things?

00:21:03.280 | - It's black, it's black and red, I guess.

00:21:06.480 | Like think of the type of magma that you see in Hawaii.

00:21:10.360 | So different types of magma flow in different ways,

00:21:12.640 | for example, so in somewhere like Io,

00:21:15.320 | the magma is really hot.

00:21:16.640 | And so it will flow out in sheets

00:21:19.120 | because it has really low viscosity.

00:21:21.720 | And I think the lava flows that we've been having in Hawaii

00:21:26.760 | over the past couple of years

00:21:27.720 | are probably a decent analogy,

00:21:29.200 | although Io's magmas, lavas are even more fluid

00:21:33.840 | and faster moving.

00:21:35.680 | - How fast, like what, how fast, like if you,

00:21:38.920 | by the way, sorry, through the telescope,

00:21:41.400 | are you tracking at what time scale?

00:21:43.560 | Like every frame is how far apart

00:21:47.520 | if you're looking through a telescope?

00:21:49.160 | Are we talking about seconds?

00:21:50.480 | Are we talking about days, months?

00:21:53.320 | When you kind of track,

00:21:54.840 | try to get a picture of what the surface might look like.

00:21:57.680 | What's the frequency?

00:21:59.520 | - So it depends a little bit on what you want to do.

00:22:02.400 | I, ideally every night,

00:22:05.320 | but you could take a frame every second

00:22:08.640 | and see how things are changing.

00:22:10.400 | The problem with that is that for things to change

00:22:13.240 | on a one second time scale,

00:22:15.560 | you to actually see something change that fast,

00:22:17.920 | you have to have super high resolution.

00:22:19.720 | The spatial resolution we have is a couple of hundred

00:22:21.640 | kilometers and so things are not changing

00:22:24.840 | on those scales over one second,

00:22:27.400 | unless you have something really crazy happening.

00:22:30.640 | - So if you get a telescope closer to Io,

00:22:34.200 | if you get a, or a camera closer to Io,

00:22:37.240 | would you be able to understand something,

00:22:39.800 | is that something of interest to you?

00:22:41.680 | Would you be able to understand something deeper

00:22:43.360 | about these volcanic eruptions and how magma flows

00:22:47.760 | and just the, like the rate of the magma,

00:22:51.480 | or is it basically enough to have the kilometer resolution?

00:22:55.000 | Do you get a sense? - No way.

00:22:56.120 | We wanna go there.

00:22:57.520 | - You wanna go to Io?

00:22:59.200 | - I mean, I don't wanna go there personally,

00:23:00.720 | but I wanna send a spacecraft mission there, absolutely.

00:23:03.040 | - Why, why are you scared?

00:23:04.920 | - Why am I scared?

00:23:05.880 | - Oh, you mean you don't,

00:23:07.120 | (laughing)

00:23:08.240 | Oh, like human.

00:23:09.640 | - I don't wanna go there as a human.

00:23:10.920 | - As a human.

00:23:11.760 | - I wanna send a robot there to look at it though.

00:23:13.520 | - This is again, everybody's discriminating against robots.

00:23:16.080 | This is not, but it's fine.

00:23:18.600 | But it's not hospitable to humans in any way, right?

00:23:22.040 | So it's very cold and very hot.

00:23:24.600 | - It's very cold.

00:23:26.000 | The atmosphere is composed of sulfur dioxide.

00:23:30.040 | So you can breathe it.

00:23:31.560 | There's no pressure.

00:23:32.600 | I mean, it's kind of all the same things you talk about.

00:23:34.680 | One talks about Mars only worse.

00:23:37.600 | The atmosphere is still a thousand times less dense

00:23:39.880 | than Mars is.

00:23:40.880 | And the radiation environment is terrible

00:23:44.880 | because you're embedded deep within Jupiter's magnetic field

00:23:48.320 | and Jupiter's magnetic field is full of charged particles

00:23:52.240 | that have all come out of Io's volcanoes actually.

00:23:56.280 | So Jupiter's magnetic field strips all this material

00:23:59.960 | out of Io's atmosphere.

00:24:01.960 | And that populates its entire magnetosphere.

00:24:04.440 | And then that material comes back around and hits Io

00:24:06.840 | and spreads throughout the system actually.

00:24:08.760 | It's just, it's like Io is the massive polluter

00:24:11.920 | of the Jupiter system.

00:24:13.120 | - Okay, cool.

00:24:15.600 | So what is studying Io teach you about volcanoes on earth

00:24:21.560 | or vice versa?

00:24:23.160 | Is in the difference of the two,

00:24:25.680 | what insights can you mine out

00:24:29.480 | that might be interesting in some way?

00:24:34.680 | - Yeah, it's, we try to port the tools

00:24:38.960 | that we use to study earth volcanism to Io

00:24:41.160 | and it works to some extent, but it is challenging

00:24:45.400 | because the situations are so different

00:24:48.360 | and the compositions are really different

00:24:49.880 | when you talk about outgassing,

00:24:51.800 | earth volcanoes outgas primarily water and carbon dioxide

00:24:56.400 | and then sulfur dioxide is the third most abundant gas.

00:25:00.000 | And on Io, the water and carbon dioxide are not there.

00:25:05.000 | Either it didn't form with them or it lost them.

00:25:08.960 | We don't know.

00:25:09.800 | And so the chemistry of how the magma outgasses

00:25:12.120 | is completely different.

00:25:14.040 | But the kind of one to me,

00:25:17.800 | most interesting analogy to earth is that,

00:25:20.960 | so Io, as I've said,

00:25:24.600 | it has these really low viscosity magmas.

00:25:26.840 | The lava spreads really quickly across its surface.

00:25:30.120 | It can put out massive volumes of magma

00:25:32.600 | in relatively short periods of time.

00:25:34.280 | And that sort of volcanism is not happening anywhere else

00:25:37.400 | in the solar system today,

00:25:39.000 | but literally every terrestrial planet and the moon

00:25:43.200 | had this, what we call very effusive volcanism

00:25:47.600 | early in their history.

00:25:48.720 | - Okay, so this is almost like a little glimpse

00:25:50.680 | into the early history of earth.

00:25:51.960 | - Yeah.

00:25:52.800 | - Okay, cool.

00:25:53.620 | So what are the chances that a volcano on earth

00:25:56.840 | destroys all of human civilization?

00:25:58.680 | Maybe I wanted to sneak in that question.

00:26:01.760 | - Yeah, a volcano on earth.

00:26:03.460 | - Do you think about that kind of stuff

00:26:07.240 | when you just study volcanoes elsewhere?

00:26:09.560 | 'Cause isn't it kind of humbling

00:26:11.800 | to see something so powerful and so hot,

00:26:14.080 | like so unpleasant for humans

00:26:16.440 | and then you realize we're sitting on many of them here?

00:26:18.680 | - Right, yeah, Yellowstone as a classic example.

00:26:22.080 | I don't know what the chances are of that happening.

00:26:26.680 | My intuition would be that the chances of that

00:26:28.920 | are lower than the chances of us getting wiped out

00:26:32.080 | by some other means.

00:26:33.440 | That in the time, that maybe it'll happen eventually,

00:26:37.200 | that there'll be one of these massive volcanoes on earth,

00:26:39.160 | but we'll probably be gone by then by some other means.

00:26:42.080 | Not to sound bleak, but.

00:26:43.480 | (both laughing)

00:26:44.400 | - That's very comforting.

00:26:45.600 | Okay, so can we talk about Europa?

00:26:49.260 | Is there, so maybe can you talk about the intuition,

00:26:55.920 | the hope that people have about life being on Europa?

00:26:59.840 | Maybe also what are the things we know about it?

00:27:03.560 | What are the things to you that are interesting

00:27:05.320 | about that particular moon of Jupiter?

00:27:08.440 | - Sure, yeah, Europa is, from many perspectives,

00:27:12.480 | one of the really interesting places in the solar system,

00:27:15.640 | among the solar system moons.

00:27:16.880 | So there are a few, there's a lot of interest

00:27:21.560 | in looking for or understanding the potential

00:27:25.280 | for life to evolve in the subsurface oceans.

00:27:27.720 | I think it's fairly widely accepted

00:27:30.160 | that the chances of life evolving on the surfaces

00:27:33.000 | of really anything in the solar system is very low.

00:27:37.520 | The radiation environment is too harsh,

00:27:42.320 | and there's just not liquids on the surface

00:27:45.360 | of most of these things, and it's canonically accepted

00:27:49.160 | that liquids are required for life.

00:27:51.080 | And so the subsurface oceans,

00:27:53.280 | in addition to maybe Titan's atmosphere,

00:27:55.080 | the subsurface oceans of the icy satellites

00:27:57.920 | are one of the most plausible places

00:28:00.560 | in the solar system for life to evolve.

00:28:03.320 | Europa and Celadus are interesting

00:28:05.480 | because for many of the big satellites,

00:28:07.520 | so Ganymede and Callisto, also satellites of Jupiter,

00:28:11.040 | also are thought to have subsurface oceans.

00:28:13.440 | But they are, so they have these ice shells,

00:28:17.280 | and then there's an ocean underneath the ice shell.

00:28:19.280 | But on those moons, or on Ganymede,

00:28:21.200 | we think that there's another ice shell underneath,

00:28:23.560 | and then there's rock.

00:28:25.200 | And the reason that that is a problem for life

00:28:27.800 | is that your ocean is probably just pure water

00:28:31.000 | because it's trapped between two big shells of ice.

00:28:34.640 | So Europa doesn't have this ice shell

00:28:38.000 | at the bottom of the ocean, we think.

00:28:39.680 | And so the water and rock are in direct interaction,

00:28:42.800 | and so that means that you can basically dissolve

00:28:45.560 | a lot of material out of the rock.

00:28:47.000 | You potentially have this hydrothermal activity

00:28:49.160 | that's injecting energy and nutrients for life to survive.

00:28:53.800 | And so this rock-water interface

00:28:56.160 | is considered really important

00:28:58.480 | for the potential habitability.

00:29:00.720 | - As a small aside, you kind of said

00:29:04.560 | that it's canonically assumed

00:29:06.120 | that water is required for life.

00:29:09.520 | Is it possible to have life in a volcano?

00:29:13.880 | I remember people,

00:29:14.960 | like in that National Geographic program or something,

00:29:20.560 | kind of hypothesizing that you can really have life anywhere

00:29:23.640 | so as long as there's a source of heat, a source of energy.

00:29:27.120 | Do you think it's possible to have life in a volcano,

00:29:31.400 | like no water?

00:29:33.360 | - I think anything's possible.

00:29:35.160 | (laughs)

00:29:36.560 | I think it's so, water, it doesn't have to be water.

00:29:40.760 | That's sort of, you can tell as you identified,

00:29:43.480 | I phrased that really carefully.

00:29:44.840 | It's canonically accepted that.

00:29:47.120 | Because we recognize that, you know,

00:29:49.320 | scientists recognize that we have no idea

00:29:51.640 | what broad range of life could be out there,

00:29:53.680 | and all we really have is our biases of life as we know it.

00:29:57.080 | But for life as we know it, it's very helpful to have,

00:29:59.760 | or even necessary to have some kind of liquid

00:30:04.320 | and preferably a polar solvent

00:30:07.680 | that can actually dissolve molecules, something like water.

00:30:09.920 | So the case of liquid methane on Titan

00:30:11.800 | is less ideal from that perspective.

00:30:13.960 | But you know, liquid magma,

00:30:16.560 | if it stays liquid long enough for life to evolve,

00:30:19.600 | you have a heat source, you have a liquid,

00:30:21.480 | you have nutrients.

00:30:22.400 | In theory, that checks your three

00:30:24.480 | classic astrobiology boxes.

00:30:27.400 | - That'd be fascinating.

00:30:29.320 | To me, it'd be fascinating

00:30:30.280 | if it's possible to detect it easily.

00:30:32.480 | How would we detect if there is life on Europa?

00:30:35.760 | Is it possible to do in a non-contact way,

00:30:41.600 | from a distance, through telescopes and so on?

00:30:43.960 | Or do we need to send robots and do some drilling?

00:30:49.840 | - I think realistically, you need to do the drilling.

00:30:54.360 | There's...

00:30:56.800 | So Europa also has these long tectonic features

00:30:59.520 | on its surface where it's thought that

00:31:01.400 | there's potential for water from the ocean

00:31:04.560 | to be somehow making its way up onto the surface.

00:31:07.760 | And you could imagine some out there scenario

00:31:10.840 | where there's bacteria in the ocean,

00:31:12.320 | it's somehow working its way up through the ice shell,

00:31:14.480 | it's spilling out on the surface,

00:31:16.120 | it's being killed by the radiation,

00:31:18.560 | but your instrument could detect

00:31:20.880 | some spectroscopic signature of that dead bacterium.

00:31:24.280 | But that's many ifs and assumptions.

00:31:26.880 | - That's a hope,

00:31:27.720 | because then you don't have to do that much drilling,

00:31:29.760 | you can collect from the surface.

00:31:31.920 | - Right, or even-- - Skeletons and bacteria.

00:31:32.760 | - I'm thinking even remotely.

00:31:34.920 | - Oh, remotely.

00:31:36.320 | Yeah.

00:31:37.960 | That's sad that there's a single cell civilization

00:31:42.040 | living underneath all that ice,

00:31:44.160 | trying to get up, trying to get out.

00:31:47.440 | - So Enceladus gives you a slightly better chance of that

00:31:52.000 | because Enceladus is a moon of Saturn,

00:31:55.280 | and it's broadly similar to Europa in some ways.

00:31:59.560 | It's an icy satellite, it has a subsurface ocean

00:32:01.760 | that's probably in touch with the rocky interior,

00:32:05.280 | but it has these massive geysers at its south pole

00:32:08.120 | where it's spewing out material

00:32:09.600 | that appears to be originating all the way from the ocean.

00:32:12.880 | And so in that case,

00:32:14.560 | you could potentially fly through that plume

00:32:18.840 | and scoop up that material

00:32:20.280 | and hope that at the velocities you'd be scooping it up,

00:32:22.640 | you're not destroying any signature

00:32:24.200 | of the life you're looking for.

00:32:25.760 | But let's say that you have some ingenuity

00:32:29.560 | and can come up with a way to do that,

00:32:31.440 | it potentially gives you a more direct opportunity,

00:32:34.800 | at least to try to measure those bacteria directly.

00:32:38.680 | - Can you tell me a little more on,

00:32:42.400 | how do you pronounce it?

00:32:44.240 | Celos?

00:32:45.080 | - Enceladus.

00:32:45.920 | - Enceladus?

00:32:46.760 | (laughs)

00:32:47.600 | Can you tell me a little bit more about Enceladus?

00:32:49.640 | Like we've been talking about way too much about Jupiter.

00:32:54.160 | Saturn doesn't get enough love.

00:32:55.000 | - Not enough really.

00:32:55.840 | - Not enough.

00:32:56.680 | (laughs)

00:32:57.840 | Saturn doesn't get as much love.

00:32:59.240 | So what's Enceladus?

00:33:02.000 | Is that the most exciting moon of Saturn?

00:33:05.040 | - Depends on your perspective.

00:33:07.400 | It's very exciting from a astrobiology perspective.

00:33:11.440 | I think Enceladus and Titan are the two most unique

00:33:15.160 | and interesting moons of Saturn.

00:33:16.800 | They definitely both get the most attention

00:33:19.120 | also from the life perspective.

00:33:21.000 | - So what's more likely, Titan or Enceladus for life?

00:33:26.360 | If you were to bet all your money in terms of like investing

00:33:32.280 | which to investigate,

00:33:33.240 | what are the difference between the two

00:33:35.360 | that are interesting to you?

00:33:37.560 | - Yeah, so the potential for life

00:33:40.200 | in each of those two places is very different.

00:33:43.160 | So Titan is the one place in the solar system

00:33:46.360 | where you might imagine,

00:33:48.200 | again, all of this is so speculative,

00:33:49.800 | but you might imagine life evolving in the atmosphere.

00:33:53.280 | So from a biology perspective,

00:33:56.120 | Titan is interesting because it forms

00:33:58.520 | complex organic molecules in its atmosphere.

00:34:01.720 | It has a dense atmosphere.

00:34:02.800 | It's actually denser than Earth's.

00:34:04.320 | It's the only moon that has an atmosphere

00:34:06.840 | denser than Earth's.

00:34:07.680 | - That's cool.

00:34:08.560 | - It's got tons of methane in it.

00:34:10.040 | What happens is that methane gets irradiated,

00:34:11.920 | it breaks up and it reforms

00:34:13.400 | with other things in the atmosphere.

00:34:15.360 | It makes these complex organic molecules

00:34:18.480 | and it's effectively doing prebiotic chemistry

00:34:21.760 | in the atmosphere.

00:34:23.240 | - While still being freezing cold?

00:34:25.160 | - Yes.

00:34:27.120 | - Okay.

00:34:28.080 | What would that be like?

00:34:29.640 | Would that be pleasant for humans to hang out there?

00:34:33.200 | Is it just really cold?

00:34:34.040 | - There's nowhere in the solar system

00:34:35.600 | that would be pleasant for humans.

00:34:37.720 | It would be cold.

00:34:38.600 | You couldn't breathe the air.

00:34:40.520 | - What colonization wise,

00:34:42.200 | if there's an atmosphere,

00:34:43.320 | isn't that a big plus?

00:34:44.840 | Or still a ton of radiation?

00:34:46.320 | Okay, so.

00:34:49.040 | Okay, so Titan,

00:34:52.080 | that's a really nice feature

00:34:53.280 | that the life could be in the atmosphere

00:34:54.760 | 'cause then it might be remotely observable

00:34:57.960 | or certainly is more accessible if you visit.

00:35:00.440 | Okay, so what about Enceladus?

00:35:05.160 | So that would be still in the ocean.

00:35:08.000 | - Right, and Enceladus has the advantage,

00:35:10.480 | like I said, of spewing material out of its south pole

00:35:13.360 | so you could collect it.

00:35:14.280 | But it has the disadvantage of the fact

00:35:16.640 | that we don't actually really understand

00:35:19.160 | how its ocean could stay frozen,

00:35:23.360 | or sorry, could stay globally liquid

00:35:26.040 | over the age of the solar system.

00:35:27.960 | And so there are some models that say

00:35:30.280 | that it's going through this cyclical evolution

00:35:34.880 | where the ocean freezes completely

00:35:36.960 | and thaws completely

00:35:38.160 | and the orbit sort of oscillates in and out

00:35:41.360 | of these eccentricities.

00:35:44.720 | And in that case,

00:35:45.920 | the potential for life ever occurring there

00:35:48.520 | in the first place is a lot lower

00:35:50.040 | because if you only have an ocean for 100 million years,

00:35:52.440 | is that enough time?

00:35:53.640 | - And it also means there might be mass extinction events

00:35:57.920 | if it does occur.

00:35:58.960 | - Right. - And it just freezes.

00:36:00.360 | Again, very sad, man.

00:36:02.120 | This is very depressing.

00:36:03.120 | All that like slaughter of life elsewhere.

00:36:06.120 | How unlikely do you think life is on Earth?

00:36:11.800 | So when you look, when you study other planets

00:36:14.640 | and you study the contents of other planets,

00:36:17.000 | does that give you a perspective

00:36:19.920 | on the origin of life on Earth?

00:36:23.280 | Which again is full of mystery in itself,

00:36:25.920 | not the evolution, but the origin,

00:36:28.200 | the first springing to life,

00:36:29.960 | like from nothing to life,

00:36:32.920 | from the basic ingredients to life.

00:36:35.720 | I guess another way of asking it is how unique are we?

00:36:40.800 | - Yeah, it's a great question.

00:36:43.520 | And it's one that just scientifically

00:36:45.560 | we don't have an answer to.

00:36:47.640 | We don't even know how many times life evolved on Earth,

00:36:51.120 | if it was only once

00:36:52.200 | or if it happened independently a thousand times

00:36:54.800 | in different places.

00:36:56.560 | We don't know whether it's happened anywhere else

00:36:59.600 | in the universe, although it feels absurd to believe

00:37:02.760 | that we are the only life that evolved

00:37:05.440 | in the entire universe, but it's conceivable.

00:37:07.560 | We just have just no real information.

00:37:12.080 | We don't understand really how life came about

00:37:14.440 | in the first place on Earth.

00:37:16.240 | - I mean, so if you look at the Drake equation

00:37:19.600 | that tries to estimate how many alien civilizations

00:37:23.760 | are out there,

00:37:24.600 | planets have a big part to play in that equation.

00:37:29.720 | If you were to bet money

00:37:31.040 | in terms of the odds of origins of life on Earth,

00:37:36.320 | I mean, this all has to do with how special

00:37:38.240 | and unique is Earth.

00:37:40.040 | What you land in terms of the number of civilizations

00:37:42.640 | has to do with how unique the rare Earth hypothesis is.

00:37:46.840 | How rare, special is Earth?

00:37:49.540 | How rare and special is the solar system?

00:37:51.800 | Like if you had to bet all your money

00:37:54.440 | on a completely unscientific question.

00:37:57.760 | Well, no, it's actually a rigorously scientific,

00:37:59.880 | we just don't know a lot of things in that equation.

00:38:03.240 | There's a lot of mysteries about that.

00:38:04.960 | And it's slowly becoming better and better understood

00:38:08.080 | in terms of exoplanets,

00:38:09.200 | in terms of how many solar systems are out there

00:38:12.080 | where there's planets, there are Earth-like planets.

00:38:14.640 | It's getting better and better understood.

00:38:16.480 | What's your sense from that perspective,

00:38:20.760 | how many alien civilizations out there?

00:38:22.880 | Zero or one plus?

00:38:25.080 | - You're right that the equation is being better understood,

00:38:29.320 | but you're really only talking about

00:38:30.680 | the first three parameters in the equation or something.

00:38:33.440 | How many stars are there?

00:38:34.480 | How many planets per star?

00:38:36.440 | And then we're just barely scratching the surface

00:38:38.980 | of what fraction of those planets might be habitable.

00:38:41.680 | The rest of the terms in the equation are like,

00:38:43.520 | how likely is life to evolve given habitable conditions?

00:38:47.080 | How likely is it to survive?

00:38:48.440 | All these things.

00:38:49.360 | There are all these huge unknowns.

00:38:52.880 | Actually, I remember when I first saw that equation,

00:38:56.080 | I think it was my first year of college.

00:38:59.480 | And I thought, this is ridiculous.

00:39:01.320 | This is A, common sense that didn't need to give a name.

00:39:06.320 | And B, just a bunch of unknowns.

00:39:09.460 | It's like putting our ignorance together in one equation.

00:39:12.120 | But I've actually, now I understand this equation.

00:39:15.600 | It's not something we ever necessarily have the answer to.

00:39:19.080 | It just gives us a framework for having

00:39:21.520 | the exact conversation we're having right now.

00:39:23.800 | And I think that's how it was intended in the first place

00:39:26.400 | when it was put into writing was to give people a language

00:39:29.320 | to communicate about the factors that go into the potential

00:39:33.120 | for aliens to be out there and for us to find them.

00:39:37.680 | I would put money on there being aliens.

00:39:41.840 | I would not put money on us having definitive evidence

00:39:46.840 | of them in my lifetime.

00:39:48.980 | - Well, definitive is a funny word.

00:39:53.920 | 'Cause my sense is, this is the saddest part for me,

00:39:58.980 | is my sense in terms of intelligent alien civilizations,

00:40:02.600 | I feel like we're so self-obsessed

00:40:08.680 | that we literally would not be able to detect them

00:40:13.120 | even when they're in front of us.

00:40:14.860 | Like trees could be aliens,

00:40:18.400 | but just their intelligence could be realized on a scale,

00:40:23.400 | on a time scale or physical scale

00:40:26.760 | that we're not appreciating.

00:40:28.660 | Like trees could be way more intelligent than us.

00:40:31.760 | I don't know, it's just a dumb example.

00:40:33.580 | Could be rocks, or it could be things like,

00:40:37.220 | I love this, this is Dawkins memes.

00:40:41.220 | It could be the ideas we have.

00:40:45.140 | Like where do ideas come from?

00:40:46.380 | Where do thoughts come from?

00:40:47.900 | Maybe thoughts are the aliens,

00:40:50.620 | or maybe thoughts is the actual mechanisms

00:40:54.140 | of communication in physics, right?

00:40:57.580 | This is like, we think of thoughts

00:40:59.200 | as something that springs up from neurons firing.

00:41:02.880 | Where the hell did they come from?

00:41:05.240 | And now what about consciousness?

00:41:07.920 | Maybe consciousness is the communication.

00:41:10.200 | It sounds like ridiculous,

00:41:12.500 | but like we're so self-centered

00:41:14.840 | on this space-time communication in physical space

00:41:19.760 | using like written language, like spoken with audio

00:41:25.720 | on a time scale that's very specific,

00:41:27.580 | on a physical scale that's very specific.

00:41:29.620 | So I tend to think that bacteria will probably recognize,

00:41:35.880 | like moving organisms will probably recognize,

00:41:38.520 | but when that forms itself into intelligence,

00:41:41.520 | most likely it'll be robots of some kind,

00:41:43.440 | 'cause we won't be meeting the origins.

00:41:45.560 | We'll be meeting the creations of those intelligences.

00:41:49.040 | We just would not be able to appreciate it,

00:41:51.320 | and that's the saddest thing to me,

00:41:53.200 | that we're too dumb to see aliens.

00:41:58.200 | Like we're too, we kind of think like,

00:42:05.000 | look at the progress of science.

00:42:06.680 | We've accomplished so much.

00:42:08.400 | The sad thing, it could be that we're just like

00:42:10.520 | in the first 0.0001% of understanding anything.

00:42:14.320 | It's humbling.

00:42:15.160 | - I hope that's true,

00:42:16.480 | because I feel like we're very ignorant as a species,

00:42:20.720 | and I hope that our current level of knowledge

00:42:23.040 | only represents the 0.001% of what we will someday achieve.

00:42:27.200 | That actually feels optimistic to me.

00:42:29.720 | - Well, I feel like that's easier for us to comprehend

00:42:32.840 | in the space of biology,

00:42:34.560 | and not as easy to comprehend in the space of physics,

00:42:37.280 | for example, because we have a sense that like,

00:42:39.720 | like if you talk to theoretical physicists,

00:42:44.920 | they have a sense that we understand the basic laws

00:42:48.160 | that form the nature of reality of our universe.

00:42:53.160 | But so there's much more,

00:42:55.720 | like physicists are much more confident.

00:42:57.840 | Biologists are like,

00:42:59.000 | this is a squishy mess, we're doing our best.

00:43:04.560 | But I would be, it'd be fascinating to see

00:43:08.400 | if physicists themselves would also be humbled

00:43:10.640 | by their being, like what the hell is dark matter

00:43:14.160 | and dark energy?

00:43:15.560 | What the hell is the, not just the origin,

00:43:19.200 | not just the Big Bang,

00:43:20.280 | but everything that happened since the Big Bang?

00:43:24.200 | A lot of things that happened since the Big Bang

00:43:25.800 | we have no ideas about except basic models of physics.

00:43:28.440 | - Right, or what happened before the Big Bang?

00:43:30.600 | - Yeah, yeah, what happened before?

00:43:32.160 | Or what's happening inside a black hole?

00:43:34.080 | Why is there a black hole at the center of our galaxy?

00:43:36.360 | Can somebody answer this?

00:43:37.400 | A supermassive black hole, nobody knows how it started,

00:43:41.400 | and they seem to be like in the middle of all galaxies.

00:43:45.360 | So that could be a portal for aliens

00:43:47.080 | to communicate through consciousness, okay.

00:43:49.680 | All right, back to planets.

00:43:51.040 | What's your favorite, outside of Earth,

00:43:55.140 | what's your favorite planet or moon?

00:43:57.520 | Maybe outside of the ones,

00:43:58.800 | well first, have we talked about it already?

00:44:01.760 | Or, and then if we did mention it,

00:44:04.560 | what's the one outside of that?

00:44:06.120 | - Oh gosh, I have to come up with another favorite

00:44:08.160 | that's not Io?

00:44:09.160 | - Oh, Io's the favorite.

00:44:10.080 | - Oh, absolutely.

00:44:10.920 | - Why is Io the favorite?

00:44:12.600 | - I mean, basically everything I've already said.

00:44:15.400 | It's just such an amazing and unique object.

00:44:19.580 | But on, I guess, a personal note,

00:44:23.420 | it's probably the object

00:44:25.120 | that made me become a planetary scientist.

00:44:28.540 | It's the first thing in the solar system

00:44:30.660 | that really deeply captured my interest.

00:44:33.920 | And when I started my PhD,

00:44:38.640 | I wanted to be an astrophysicist

00:44:41.840 | working on things like galaxy evolution.

00:44:44.000 | And sort of slowly,

00:44:46.240 | I had done some projects in the solar system,

00:44:48.360 | but Io was the thing that really caught me

00:44:50.840 | into doing solar system science.

00:44:53.600 | - Okay, let's leave moons aside.

00:44:56.840 | What's your favorite planet?

00:44:58.880 | It sounds like you like moons better than planets.

00:45:01.040 | So let's--

00:45:02.240 | - That's accurate.

00:45:03.360 | But the planets are fascinating.

00:45:05.760 | I think, you know,

00:45:07.800 | I find the planets in the solar system really fascinating.

00:45:10.480 | What I like about the moons is that

00:45:13.040 | there's so much less that is known.

00:45:16.960 | There's still a lot more discovery space

00:45:18.840 | and the questions that we can ask

00:45:20.520 | are still the bigger questions.

00:45:22.840 | - Gotcha.

00:45:23.680 | - Which, you know,

00:45:24.520 | and maybe I'm being unfair to the planets

00:45:27.120 | because we're still trying to understand things

00:45:29.760 | like was there ever life on Mars?

00:45:31.540 | And that is a huge question

00:45:32.960 | and one that we've sent numerous robots to Mars

00:45:35.920 | to try to answer.

00:45:37.360 | So maybe I'm being unfair to the planets.

00:45:39.680 | But there is certainly quite a bit more information

00:45:42.520 | that we have about the planets than the moons.

00:45:45.040 | But I mean, Venus is a fascinating object.

00:45:48.180 | So I like the objects that lie at the extremes.

00:45:53.180 | I think that if we can make a sort of theory

00:45:57.560 | or like I've been saying,

00:45:58.880 | framework for understanding planets and moons

00:46:01.120 | that can incorporate even the most extreme ones,

00:46:03.560 | then, you know, those are the things

00:46:04.920 | that really test your theory and test your understanding.

00:46:08.200 | So they've always really fascinated me.

00:46:10.200 | Not so much the nice habitable places like Earth,

00:46:12.560 | but these extreme places like Venus

00:46:15.240 | that have sulfuric acid clouds

00:46:20.160 | and just incredibly hot and dense surfaces.

00:46:23.480 | And Venus, of course, I love volcanism for some reason.

00:46:27.200 | And Venus has, probably has volcanic activity,

00:46:31.360 | definitely has in their recent past,

00:46:33.160 | maybe has ongoing today.

00:46:36.760 | - What do you make of the news?

00:46:38.800 | Maybe you can update it in terms of life being discovered

00:46:42.000 | in the atmosphere of Venus.

00:46:44.120 | Is that, sorry, okay.

00:46:46.280 | You have an opinion.

00:46:47.120 | I can already tell you have opinions.

00:46:48.960 | Was that fake news?

00:46:50.600 | I got excited when I saw that.

00:46:52.600 | What's the final, is there a life on Venus?

00:46:56.320 | - So the detection that was reported

00:46:58.440 | was the detection of the molecule phosphine.

00:47:00.780 | And they said that they tried every other mechanism

00:47:07.400 | they could think of to produce phosphine

00:47:10.480 | and no mechanism worked.

00:47:13.600 | And then they said, well, we know that life produces phosphine

00:47:16.720 | and so that was sort of the train of logic.

00:47:19.460 | And I don't personally believe that phosphine

00:47:24.360 | was detected in the first place.

00:47:26.320 | - Okay, so then, I mean, this is just one study,

00:47:28.760 | but I, as a layman, am skeptical a little bit

00:47:35.240 | about tools that sense the contents of an atmosphere,

00:47:38.600 | like contents of an atmosphere from remotely

00:47:43.600 | and making conclusive statements about life.

00:47:47.240 | - Oh, yeah, well, that connection that you just made,

00:47:49.600 | the contents of the atmosphere to the life

00:47:52.240 | is a tricky one.

00:47:54.460 | And yeah, I know that that claim received a lot of criticism

00:47:58.720 | for the lines of logic that went from detection

00:48:02.280 | to claim of life.

00:48:04.840 | Even the detection itself, though,

00:48:07.280 | doesn't meet the sort of historical scientific standards

00:48:12.280 | of a detection.

00:48:14.180 | It was a very tenuous detection

00:48:18.100 | and only one line of the species was detected

00:48:20.600 | and a lot of really complicated data analysis methods

00:48:24.320 | had to be applied to even make that weak detection.

00:48:27.880 | - Yeah, so it could be noise, it could be polluted data,

00:48:31.920 | it could be all those things.

00:48:33.240 | And so it doesn't meet the level of rigor

00:48:37.440 | that you would hope, but of course,

00:48:39.080 | I mean, we're doing our best.

00:48:40.560 | And it's clear that the human species

00:48:44.640 | are hopeful to find life.

00:48:47.000 | - Clearly, yes.

00:48:48.240 | Everyone is so excited about that possibility.

00:48:51.160 | - All right, let me ask you about Mars.

00:48:54.480 | So there's a guy named Elon Musk

00:49:02.780 | and he seems to wanna take something called Dogecoin there.

00:49:07.240 | First of the moon.

00:49:08.140 | I'm just kidding about the Dogecoin.

00:49:11.980 | I don't even know what the heck is up with that whole.

00:49:16.300 | I think humor has power in the 21st century

00:49:21.300 | in a way to spread ideas in the most positive way.

00:49:28.440 | So I love that kind of humor

00:49:32.640 | 'cause it makes people smile,

00:49:35.580 | but it also kinda sneak,

00:49:37.180 | it's like a Trojan horse for cool ideas.

00:49:39.660 | You open with humor and you,

00:49:43.460 | like the humor is the appetizer

00:49:45.360 | and then the main meal is the science and the engineering.

00:49:48.980 | Anyway, do you think it's possible to colonize Mars

00:49:53.980 | or other planets in the solar system,

00:50:00.500 | but we're especially looking to Mars.

00:50:04.180 | Is there something about planets

00:50:06.440 | that make them very harsh to humans?

00:50:08.940 | Is there something in particular you think about

00:50:11.300 | and maybe in a high, like big picture perspective,

00:50:14.600 | do you have a hope we do in fact

00:50:17.000 | become a multi-planetary species?

00:50:18.820 | - I do think that if our species survives long enough

00:50:24.760 | and we don't wipe ourselves out

00:50:26.780 | or get wiped out by some other means

00:50:28.580 | that we will eventually be able to colonize other planets.

00:50:33.580 | I do not expect that to happen in my lifetime.

00:50:36.460 | I mean, tourists may go to Mars, tourists,

00:50:39.020 | people who commit years of their life

00:50:41.040 | to go into Mars as a tourist may go to Mars.

00:50:43.640 | I don't think that we will colonize it.

00:50:47.500 | - Is there a sense why it's just too harsh

00:50:49.740 | for an environment to,

00:50:52.220 | like it's too costly to build something habitable there

00:50:56.940 | for a large population?

00:50:58.600 | - I think that we need to do a lot of work

00:51:03.420 | in learning how to use the resources

00:51:05.900 | that are on the planet already to do the things we need.

00:51:09.420 | So if you're talking about someone going there

00:51:11.200 | for a few months,

00:51:12.460 | so I'll back up a little bit.

00:51:17.420 | There are many things that make Mars

00:51:19.460 | not hospitable, temperature, you can't breathe the air,

00:51:22.620 | you need a pressure suit, even if you're on the surface,

00:51:25.460 | the radiation environment is,

00:51:27.540 | even in all of those things,

00:51:28.620 | the radiation environment is too harsh for the human body.

00:51:32.340 | All of those things seem like they could eventually have

00:51:36.060 | technological solutions.

00:51:38.160 | The challenge, the real significant challenge to me

00:51:43.780 | seems to be the creation

00:51:46.240 | of a self-sustaining civilization there.

00:51:49.820 | You can bring pressure suits,

00:51:51.800 | you can bring oxygen to breathe,

00:51:53.480 | but those are all in limited supply.

00:51:55.120 | And if we're gonna colonize it,

00:51:56.320 | we need to find ways to make use of the resources

00:51:59.920 | that are there to do things like produce food,

00:52:03.120 | produce the air that humans need to keep breathing,

00:52:05.280 | just in order to make it self-sustaining,

00:52:07.060 | there's a tremendous amount of work that has to be done.

00:52:09.540 | And people are working on these problems,

00:52:11.900 | but I think that's gonna be a major obstacle

00:52:15.540 | in going from visiting where we can bring everything

00:52:18.360 | we need to survive in the short term

00:52:20.180 | to actually colonizing.

00:52:22.820 | - Yeah, I find that whole project

00:52:26.640 | of the human species quite inspiring,

00:52:29.240 | these like huge moonshot projects.

00:52:31.860 | Somebody, I was reading something

00:52:36.260 | in terms of the source of food

00:52:37.580 | that may be the most effective on Mars

00:52:40.580 | is you could farm insects.

00:52:42.700 | That's the easiest thing to farm.

00:52:44.860 | So we'll be eating like cockroaches

00:52:47.300 | before living on Mars,

00:52:49.980 | 'cause that's the easiest thing to actually,

00:52:52.900 | as a source of protein.

00:52:54.580 | So growing a source of protein

00:52:56.060 | is the easiest thing as insects.

00:52:58.700 | I just imagine this giant,

00:53:01.020 | for people who are afraid of insects,

00:53:03.140 | this is not a pleasant,

00:53:04.980 | maybe you're not supposed to even think of it that way.

00:53:07.180 | It'll be like a cockroach milkshake or something like that.

00:53:09.820 | - Right, I wonder,

00:53:11.100 | have people been working on the genetic engineering

00:53:13.780 | of insects to make them-

00:53:16.180 | - Radiation friendly.

00:53:18.660 | - Right, or pressure resistant or whatever,

00:53:21.220 | to make them more-

00:53:22.420 | - What can possibly go wrong?

00:53:24.380 | Cockroaches become radiation resistant.

00:53:26.820 | They're already like survived everything.

00:53:29.420 | Plus I took an allergy test in Austin.

00:53:32.820 | So there's everybody's like,

00:53:34.540 | the allergy levels are super high there.

00:53:36.540 | And one of the things apparently,

00:53:39.860 | I'm not allergic to any insects except cockroaches.

00:53:43.220 | It's hilarious.

00:53:44.260 | So maybe, well, I'm gonna use that as,

00:53:48.900 | you know how people use an excuse

00:53:51.100 | that I'm allergic to cats, to not have cats.

00:53:53.020 | I'm gonna use that as an excuse to not go to Mars

00:53:55.940 | as one of the first batch of people.

00:53:57.900 | - I was gonna ask,

00:53:58.940 | if you had the opportunity, would you go?

00:54:01.140 | - Yeah, I'm joking about the cockroach thing.

00:54:03.140 | I would definitely go.

00:54:04.060 | I love challenges.

00:54:05.380 | I love doing things where the possibility of death

00:54:11.580 | is not insignificant.

00:54:17.340 | 'Cause it makes me appreciate it more.

00:54:19.700 | Meditating on death makes me appreciate life.

00:54:26.380 | And when the meditation on death is forced on you,

00:54:32.460 | 'cause of how difficult the task is,

00:54:34.860 | I enjoy those kinds of things.

00:54:37.620 | Most people don't, it seems like.

00:54:39.900 | But I love the idea of difficult journeys

00:54:43.740 | for no purpose whatsoever except exploration,

00:54:47.980 | going into the unknown,

00:54:49.660 | seeing what the limits of the human mind

00:54:51.540 | and the human body are.

00:54:53.260 | It's like, what the hell else is this whole journey

00:54:55.340 | that we're on for?

00:54:56.420 | But it could be 'cause I grew up in the Soviet Union.

00:55:00.140 | There is a kind of love for space,

00:55:03.940 | like the space race, the Cold War created.

00:55:07.180 | I don't know if still it permeates American culture as much,

00:55:11.460 | but especially with the dad as a scientist,

00:55:14.100 | I think I've loved the idea of humans

00:55:18.660 | striving out towards the stars, always.

00:55:21.740 | Like from the engineering perspective,

00:55:23.860 | has been really exciting.

00:55:24.820 | I don't know if people love that as much in America anymore.

00:55:27.100 | I think Elon is bringing that back a little bit,

00:55:30.420 | that excitement about rockets and going out there.

00:55:33.660 | But so that's hopeful.

00:55:36.100 | But for me, I always loved that idea.

00:55:37.940 | From an alien scientist perspective,

00:55:40.900 | if you were to look back on earth,

00:55:43.500 | is there something interesting you could say about earth?

00:55:49.260 | Like how would you summarize earth?

00:55:51.060 | You know, like "Hitchhiker's Guide to the Galaxy."

00:55:54.900 | Like if you had to report, like write a paper on earth

00:55:58.940 | or like a letter, like a one pager,

00:56:01.540 | summarizing the contents of the surface and the atmosphere.

00:56:05.540 | Is there something interesting?

00:56:07.140 | Like, do you ever take that kind of perspective on it?

00:56:10.700 | - I know you like volcanism,

00:56:12.340 | so volcanoes, that'll probably be in the report.

00:56:15.100 | - I was gonna say, that's where I was gonna go first.

00:56:17.620 | There are a few things to say about the atmosphere,

00:56:19.260 | but in terms of the volcanoes,

00:56:20.500 | so one of the really interesting puzzles

00:56:25.340 | to me in planetary science is,

00:56:27.420 | so we can look out there and we've been talking about

00:56:30.060 | surfaces and volcanoes and atmospheres and things like that.

00:56:33.740 | But that is just, you know, this tiny little veneer

00:56:36.580 | on the outside of the planet.

00:56:37.660 | And most of the planet is completely

00:56:40.180 | sort of inaccessible to telescopes

00:56:42.060 | or to spacecraft missions.

00:56:43.180 | You can drill a meter into the surface,

00:56:44.820 | but you know, that's still really the veneer.

00:56:47.060 | And one of the cool puzzles is looking at what's going on

00:56:52.060 | on the surface and trying to figure out

00:56:54.820 | what's happening underneath,

00:56:56.220 | or just any kind of indirect means

00:56:59.180 | that you have to study the interior

00:57:00.740 | because you can't dig into it directly, even on earth,

00:57:03.860 | you can't dig deep into earth.

00:57:06.580 | So from that perspective, looking at earth,

00:57:09.660 | one thing that you would be able to tell from orbit,

00:57:14.340 | given enough time, is that earth has tectonic plates.

00:57:18.580 | So you would see that volcanoes follow the edges.

00:57:22.820 | If you trace where all the volcanoes are on earth,

00:57:24.620 | they follow these lines that trace the edges of the plates.

00:57:28.140 | And similarly, you would see things like

00:57:30.260 | the Hawaiian string of volcanoes that you could infer,

00:57:35.340 | just like we did as people actually living on earth,

00:57:39.020 | that the plates are moving over some plume

00:57:41.300 | that's coming up through the mantle.

00:57:42.820 | And so you could use that to say,

00:57:45.540 | if the aliens could look at where the volcanoes

00:57:47.620 | are happening on earth and say something about

00:57:50.100 | the fact that earth has plate tectonics,

00:57:51.620 | which makes it really unique in the solar system.

00:57:54.340 | - So the other planets don't have plate tectonics?

00:57:56.580 | - It's the only one that has plate tectonics, yeah.

00:57:59.180 | - What about Io and the friction and all that,

00:58:02.420 | that's not plate tectonics?

00:58:03.620 | What's the difference between,

00:58:05.140 | so oh, it's plate tectonics,

00:58:07.340 | like another layer of like solid rock

00:58:10.060 | that moves around and there's cracks.

00:58:12.740 | - Yeah, so earth has plates of solid rock

00:58:16.380 | sitting on top of a partially molten layer,

00:58:19.220 | and those plates are kind of shifting around.

00:58:22.620 | On Io, it doesn't have that,

00:58:25.860 | and the volcanism is what we call heat pipe volcanism.

00:58:28.740 | It's the magma just punches a hole through the crust

00:58:31.580 | and comes out on the surface.

00:58:32.820 | I mean, that's a simplification,

00:58:34.140 | but that's effectively what's happening.

00:58:36.180 | - Through the freezing cold crust.

00:58:37.780 | - Yes, very cold, very rigid crust, yeah.

00:58:42.060 | - How does that look like, by the way?

00:58:44.280 | I don't think we've mentioned,

00:58:46.620 | so the gas that's expelled,

00:58:48.540 | like if we were to look at it,

00:58:49.780 | is it beautiful or is it like boring?

00:58:51.940 | - The gas?

00:58:52.780 | - Like the whole thing,

00:58:54.100 | like the magma punching through the icy--

00:58:57.380 | - Yes, I'm sure it would be beautiful,

00:58:58.900 | and the pictures we've seen of it are beautiful.

00:59:00.660 | You have, so the magma will come out of the lava,

00:59:04.820 | will come out of these fissures,

00:59:06.500 | and you have these curtains of lava

00:59:09.940 | that are maybe even a kilometer high.

00:59:13.580 | So if you looked at videos,

00:59:15.060 | I don't know how many volcano videos

00:59:16.820 | you've looked at on Earth,

00:59:17.660 | but you sometimes see a tiny, tiny version of this.

00:59:20.020 | In Iceland, you see just these sheets of magma

00:59:22.140 | coming out of a fissure

00:59:23.540 | when you have this really low viscosity magma,

00:59:26.900 | sort of water-like coming out at these sheets.

00:59:29.500 | And the plumes that come out,

00:59:31.340 | because there's no atmosphere,

00:59:33.580 | all the plume molecules are just,

00:59:36.700 | or plume particles,

00:59:38.300 | where they end up is just a function

00:59:40.740 | of the direction that they left the vent,

00:59:43.660 | so they're all following ballistic trajectories.

00:59:46.460 | And you end up with these umbrella plumes.

00:59:48.820 | You don't get these sort of complicated plumes

00:59:50.700 | that you have on Earth that are occurring

00:59:53.260 | because of how that material's interacting

00:59:55.140 | with the atmosphere that's there.

00:59:56.620 | You just have these huge umbrellas.

00:59:58.580 | And it's been hypothesized, actually,

01:00:00.220 | that the atmosphere's made of sulfur dioxide

01:00:03.100 | and that you could have these kind of ash particles

01:00:07.500 | from the volcano,

01:00:08.340 | and the sulfur dioxide would condense onto these particles,

01:00:12.980 | and you'd have sulfur dioxide snow

01:00:14.900 | coming out of these volcanic plumes.

01:00:16.700 | - And there's not much light, though, right?

01:00:21.220 | So you wouldn't be able to,

01:00:22.260 | like, it would not make a good Instagram photo

01:00:24.860 | 'cause you have to,

01:00:26.540 | would you see the snow?

01:00:28.460 | - Sure.

01:00:29.300 | There's light.

01:00:30.140 | It depends.

01:00:30.980 | - Oh, okay, so you could, okay.

01:00:32.820 | - Depends what angle you're looking at it,

01:00:34.420 | where the sun is, all the things like that.

01:00:36.220 | You know, the sunlight is much weaker,

01:00:37.700 | but it's still there.

01:00:38.540 | - It's still there.

01:00:39.380 | And how big is Io in terms of gravity?

01:00:43.860 | Is it smaller?

01:00:44.900 | Is it a pretty small moon?

01:00:46.180 | - It's quite a bit smaller than Earth, anyway.

01:00:49.820 | - It's smaller than Earth, okay.

01:00:51.780 | Okay, cool.

01:00:52.620 | So they float out for a little bit.

01:00:54.700 | So the floats, yeah, no, you're right.

01:00:56.780 | That would be gorgeous.

01:00:58.860 | What else about Earth is interesting besides volcanoes?

01:01:03.700 | So plate tectonics,

01:01:04.740 | I didn't realize that that was a unique element

01:01:07.740 | of a planet in the solar system.

01:01:09.660 | 'Cause that, I wonder what,

01:01:14.500 | I mean, we experience it as human beings.

01:01:16.300 | It's quite painful because of earthquakes

01:01:17.940 | and all those kinds of things,

01:01:18.820 | but I wonder if there's nice features to it.

01:01:21.620 | - Yeah, so coming back to habitability again,

01:01:26.660 | things like tectonics and plate tectonics

01:01:29.220 | are thought to play an important role

01:01:31.740 | in the surface being habitable.

01:01:33.100 | And that's because you have a way of recycling materials.

01:01:36.740 | So if you have a stagnant surface,

01:01:39.380 | everything, you use up all the free oxygen,

01:01:41.820 | everything reacts until you no longer have reactants

01:01:45.260 | that life can extract energy from.

01:01:47.940 | And so if nothing's changing on your surface,

01:01:49.740 | you kind of reach this stagnation point.

01:01:53.660 | But something like plate tectonics recycles material.

01:01:57.140 | You bring up new fresh material from the interior,

01:01:59.420 | you bring down material that's up on the surface,

01:02:02.220 | and that can kind of refresh your nutrient supply

01:02:06.900 | in a sense, or the sort of raw materials

01:02:09.180 | that the surface has to work with.

01:02:11.820 | So from a kind of astrobiologist perspective,

01:02:16.820 | looking at Earth, you would see that recycling of material

01:02:20.300 | because the plate tectonics,

01:02:21.420 | you would also see how much oxygen is in Earth's atmosphere.

01:02:25.060 | And between those two things,

01:02:26.340 | you would identify Earth as a reasonable candidate

01:02:30.140 | for a habitable environment.

01:02:32.020 | In addition to of course,

01:02:33.020 | the pleasant temperature and liquid water.

01:02:36.180 | But the abundance of oxygen and the plate tectonics

01:02:39.780 | both play a role as well.

01:02:42.180 | - And also see like tiny dot satellites flying around.

01:02:44.980 | - Well, sure, yes.

01:02:46.820 | - I wonder if they would be able to,

01:02:48.020 | I really think about that.

01:02:48.940 | Like if aliens were to visit,

01:02:51.860 | and would they really see humans

01:02:54.900 | as the thing they should be focusing on?

01:02:56.960 | I think it would take a while, right?

01:03:01.140 | Is it so obvious that that should,

01:03:03.940 | 'cause there's like so much incredible,

01:03:05.900 | in terms of biomass,

01:03:07.500 | humans are a tiny, tiny, tiny fraction.

01:03:10.060 | There's like ants.

01:03:11.160 | They would probably detect ants, right?

01:03:14.980 | Or they probably would focus on the water and the fish.

01:03:17.900 | 'Cause there's like a lot of water.

01:03:20.300 | I was surprised to learn that there's more species on land

01:03:23.220 | than there is in the sea.

01:03:24.940 | Like there's 90,

01:03:26.120 | I think 90 to 95% of the species are on land.

01:03:29.260 | - Or on land, or not in the sea.

01:03:31.380 | - Not in the sea.

01:03:32.700 | I thought like there's so much going on in the sea,

01:03:34.940 | but no, the variety that like the branches

01:03:38.380 | created by evolution,

01:03:39.780 | apparently it's probably a good answer

01:03:42.220 | from evolutionary biology perspective,

01:03:43.900 | why land created so much diversity, but it did.

01:03:46.900 | So like the sea,

01:03:48.020 | there's so much not known about the sea,

01:03:50.700 | about the oceans,

01:03:51.660 | but it's not diversity friendly.

01:03:56.660 | What can I say?

01:03:58.220 | It needs to improve its diversity.

01:04:01.500 | - Do you think the aliens would come?

01:04:03.220 | I mean, the first thing they would see is,

01:04:04.620 | I suppose, are cities.

01:04:05.940 | Assuming that they had some idea

01:04:07.340 | of what a natural world looked like,

01:04:10.100 | they would see cities and say, "These don't belong.

01:04:13.380 | Which of these many species created these?"

01:04:15.980 | - Yeah, I mean, if I were to guess,

01:04:18.620 | it's a good question.

01:04:21.620 | I don't know if you do this,

01:04:23.740 | when you look at the telescope,

01:04:24.980 | whether you look at geometric shapes.

01:04:28.620 | 'Cause to me, like hard corners,

01:04:34.980 | like what do we think is engineered?

01:04:36.780 | Things that are like,

01:04:38.900 | have kind of straight lines and corners and so on.

01:04:41.880 | They will probably detect those

01:04:43.200 | in terms of buildings would stand out to them.

01:04:45.500 | Because that goes against

01:04:47.500 | the basic natural physics of the world.

01:04:50.980 | But I don't know if the electricity and lights and so on,

01:04:56.700 | it could be,

01:04:57.540 | I honestly, it could be the plate tectonics.

01:05:01.100 | It could be like, hmm,

01:05:02.500 | that like the volcanoes,

01:05:04.220 | that'd be okay, that's a source of heat.

01:05:05.820 | And then they would focus.

01:05:07.100 | They might literally,

01:05:08.860 | I mean, depending on how alien life forms are,

01:05:11.340 | they might notice the microorganisms

01:05:14.580 | before they notice the big,

01:05:17.020 | like notice the ant before the elephant.

01:05:19.120 | 'Cause like there's a lot more of them,

01:05:22.640 | depending what they're measuring device.

01:05:23.980 | We think like size matters,

01:05:25.420 | but maybe with their tools of measurement,

01:05:28.700 | they would look for quantity versus size.

01:05:32.300 | Like why focus on the big thing,

01:05:34.540 | focus on the thing that there's a lot of.

01:05:36.860 | And when they see humans,

01:05:37.940 | depending on their measurement devices,

01:05:39.520 | they might see we're made up of billions of organisms.

01:05:43.660 | Like the fact that we're very human,

01:05:46.220 | we think we're one organism,

01:05:47.900 | but that may not be the case.

01:05:49.860 | They might see, in fact,

01:05:50.940 | they may also see like a human city as one organism.

01:05:55.420 | Like what is this thing that like,

01:05:58.980 | clearly this organism gets aroused at night

01:06:03.740 | 'cause the lights go on.

01:06:04.980 | And then it like, it sleeps during the day.

01:06:10.180 | I don't know.

01:06:12.900 | Like what perspective you take on the city.

01:06:15.060 | Is there something interesting about earth

01:06:18.420 | or other planets in terms of weather patterns?

01:06:20.820 | So we talked a lot about volcanic patterns.

01:06:25.820 | Is there something else about weather that's interesting,

01:06:29.980 | like storms or variations in temperature,

01:06:34.420 | all those kinds of things?

01:06:35.720 | - Yeah, so there's sort of,

01:06:40.420 | every planet and moon has a kind of interesting

01:06:43.220 | and unique weather pattern.

01:06:44.740 | And those weather patterns are really,

01:06:48.400 | we don't have a good understanding of them.

01:06:50.780 | We don't even have a good understanding

01:06:52.180 | of the global circulation patterns

01:06:54.860 | of many of these atmospheres,

01:06:58.740 | why the storm systems occur.

01:07:00.420 | So the composition and occurrence of storms

01:07:05.420 | and clouds and these objects

01:07:07.860 | is another one of these kind of windows into the interior

01:07:11.940 | that I was talking about with surfaces.

01:07:13.680 | One of these ways that we can get perspective

01:07:16.500 | and what the composition is of the interior

01:07:18.500 | and how the circulation is working.

01:07:20.340 | So circulation will bring some species up

01:07:24.600 | from deeper in the atmosphere of the planet

01:07:26.740 | to some altitude that's a little bit colder

01:07:28.820 | and that species will condense out

01:07:30.360 | and form a cloud at that altitude.

01:07:32.340 | And we can detect in some cases

01:07:35.500 | what those clouds are composed of.

01:07:38.500 | And looking at where those occur

01:07:42.940 | can tell you how the circulation cells are,

01:07:45.620 | whether the atmospheric circulation is say,

01:07:48.020 | coming up at the equator and going down at the poles

01:07:50.980 | or whether you have multiple cells in the atmosphere.

01:07:53.300 | And I mean, Jupiter's atmosphere is just insane.

01:07:57.820 | There's so much going on.

01:07:58.900 | You look at these pictures

01:07:59.900 | and there's all these vortices and anti-vortices

01:08:02.540 | and you have these different bands

01:08:03.980 | that are moving in opposite directions

01:08:06.600 | that may be giving you information

01:08:09.320 | about the deep in the atmosphere,

01:08:14.320 | physically deep properties

01:08:16.100 | of Jupiter's interior and circulation.

01:08:21.100 | - What are these vortices?

01:08:24.380 | What's the basic material of the storms?

01:08:27.620 | - It's condensed molecules from the atmosphere.

01:08:30.020 | So ammonia ice particles in the case of Jupiter,

01:08:33.460 | it's methane ice in the case of let's say Uranus and Neptune

01:08:37.160 | and other species, you can kind of construct

01:08:40.040 | a chemical model for which species can condense where.

01:08:42.720 | And so you see a cloud at a certain altitude

01:08:45.440 | within the atmosphere and you can make a guess

01:08:47.320 | at what that cloud is made of

01:08:48.960 | and sometimes measure it directly

01:08:50.800 | and different species make different colors as well.

01:08:54.080 | - Oh, cool.

01:08:55.000 | Ice storms, okay.

01:08:57.320 | - I mean, the climate of Uranus

01:08:58.760 | has always been fascinating to me

01:09:00.760 | because it orbits on its side

01:09:03.360 | and it has a 42 year orbital period.

01:09:07.360 | And so, with earth, our seasons are

01:09:09.600 | because our equator is tipped just a little bit

01:09:11.880 | to the plane that we orbit in.

01:09:13.160 | So sometimes the sunlight's a little bit above the equator

01:09:15.400 | and sometimes it's a little bit below the equator.

01:09:17.360 | But on Uranus, it's like for 10 years,

01:09:20.880 | the sunlight is directly on the North Pole

01:09:22.880 | and then it's directly on the equator

01:09:24.280 | and then it's directly on the South Pole.

01:09:26.520 | And it's actually kind of amazing

01:09:29.200 | that the atmosphere doesn't look crazier than it does.

01:09:33.360 | But understanding how, taking again,

01:09:35.600 | like one of these extreme examples,

01:09:37.400 | if we can understand why that atmosphere behaves

01:09:40.320 | in the way it does, it's kind of a test

01:09:42.560 | of our understanding of how atmosphere is.

01:09:45.760 | - So like heats up one side of the planet for 10 years

01:09:50.760 | and then freezes it the next,

01:09:55.360 | and that you're saying should probably lead to some chaos

01:09:59.240 | and it doesn't.

01:10:01.720 | - The fact that it doesn't tells you something

01:10:03.600 | about the atmosphere.

01:10:04.760 | So atmospheres have a property that surfaces don't have,

01:10:07.160 | which is that they can redistribute heat

01:10:08.720 | a lot more effectively.

01:10:10.640 | - So they're a stabilizing, like self-regulating aspect

01:10:14.280 | to them that they're able to deal with extreme conditions.

01:10:17.180 | But predicting how that complex system unrolls

01:10:24.560 | is very difficult as we know

01:10:26.640 | about predicting the weather on earth even.

01:10:28.560 | - Oh my goodness.

01:10:29.400 | - Even with a little variation we have on earth.

01:10:31.360 | - You know, people have tried to put together

01:10:33.640 | global circulation models.

01:10:35.000 | So, you know, we've done this for earth.

01:10:36.100 | People have tried to do these for other planets as well.

01:10:38.600 | And it is a really hard problem.

01:10:40.700 | So Titan, for example, like I said,

01:10:43.440 | it's one of the best studied atmospheres

01:10:45.480 | in the solar system.

01:10:46.320 | And people have tried to make these global circulation models

01:10:49.560 | and actually predict what's going to happen

01:10:52.640 | moving into sort of the next season of Titan.

01:10:55.000 | And those predictions have ended up being wrong.

01:10:57.000 | And so then, you know, I don't know,

01:10:59.120 | it's always exciting when a prediction is wrong

01:11:00.880 | because it means that there's something more to learn.

01:11:03.520 | Like your theory wasn't sufficient.

01:11:05.920 | And then you get to go back and learn something

01:11:07.640 | by how you have to modify the theory to make it fit.

01:11:10.340 | - I'm excited by the possibility of one day

01:11:13.840 | there'll be for various moons and planets,

01:11:15.920 | there'll be like news programs reporting the weather

01:11:20.680 | with the fake confidence of like,

01:11:22.640 | as if you can predict the weather.

01:11:24.360 | We talked quite a bit about planets and moons.

01:11:28.520 | Can we talk a little bit about asteroids?

01:11:31.760 | - For sure.

01:11:32.600 | - What's an asteroid and what kind of asteroids are there?

01:11:36.840 | - So the asteroids, let's talk about just the,

01:11:39.540 | restricted to the main asteroid belt, which is the region.

01:11:42.960 | It's a region of debris basically between Mars and Jupiter.

01:11:49.000 | And the, these sort of belts of debris

01:11:54.000 | throughout the solar system, the outer solar system,

01:11:58.560 | you know, the Kuiper belt that we talked about,

01:12:00.120 | the asteroid belt, as well as certain other populations

01:12:02.640 | where they accumulate

01:12:03.720 | because they're gravitationally more favored,

01:12:07.400 | are remnant objects from the origin of the solar system.

01:12:11.560 | And so one of the reasons that we are so interested in them,

01:12:16.040 | aside from potentially the fact

01:12:17.480 | that they could come hit Earth,

01:12:18.880 | but scientifically it's,

01:12:22.560 | it gives us a window into understanding the composition

01:12:29.400 | of the material from which Earth

01:12:32.600 | and the other planets formed

01:12:34.160 | and how that material was kind of redistributed

01:12:37.440 | over the history of the solar system.

01:12:39.840 | So the asteroids,

01:12:41.760 | one could classify them in two different ways.

01:12:44.040 | Some of them are ancient objects.

01:12:45.880 | So they accreted out of the sort of disc of material

01:12:50.880 | that the whole solar system formed out of

01:12:55.480 | and have kind of remained ever since more or less the same.

01:13:00.480 | They've probably collided with each other

01:13:04.240 | and we see all these collisional fragments.

01:13:06.360 | And you can actually look and based on their orbits,

01:13:10.640 | say, you know, like these 50 objects

01:13:13.160 | originated as the same object.

01:13:16.240 | You can see them kind of dynamically moving apart

01:13:18.440 | after some big collision.

01:13:19.960 | And so some of them are these ancient objects,

01:13:24.400 | maybe that have undergone collisions.

01:13:26.000 | And then there's this other category of object

01:13:28.200 | that is the one that I personally find really interesting,

01:13:30.960 | which is remnants of objects that could have been planets.

01:13:38.400 | So early on, a bunch of potential planets accreted

01:13:43.160 | that we call planetesimals and they formed

01:13:45.600 | and they formed with a lot of energy

01:13:46.920 | and they had enough time to actually differentiate.

01:13:49.100 | So some of these objects differentiated

01:13:50.800 | into cores and mantles and crusts.

01:13:53.280 | And then they were subsequently distracted

01:13:57.040 | in these massive collisions.

01:13:59.000 | And now we have these fragments,

01:14:02.440 | we think fragments floating around the asteroid belt

01:14:05.000 | that are like bits of mantle, bits of core, bits of crust.

01:14:08.320 | - Cool. - Basically.

01:14:10.120 | - So it's like puzzle pieces

01:14:11.160 | that you might be able to stitch together

01:14:13.480 | or I guess it's all mixed up

01:14:17.800 | so you can't stitch together the original planet candidates

01:14:22.200 | or is that possible to try to see if they kind of,

01:14:25.040 | I mean, there's too many objects in there to.

01:14:28.920 | - I think that there are cases

01:14:30.240 | where people have kind of looked at objects

01:14:33.000 | and by looking at their orbits,

01:14:34.580 | they say these objects should have originated together

01:14:37.000 | but they have very different compositions.

01:14:39.520 | And so then you can hypothesize

01:14:41.600 | maybe they were different fragments

01:14:43.160 | of a differentiated object.

01:14:44.840 | But one of the really cool things about this is,

01:14:47.240 | we've been talking about getting clues

01:14:50.320 | into the interiors of planets.

01:14:52.480 | We've never seen a planetary core or deep mantle directly.

01:14:57.440 | Some mantle material comes up on our surface

01:14:59.360 | and then we can see it, but in sort of in bulk.

01:15:02.700 | We haven't seen these things directly

01:15:05.080 | and these asteroids potentially give us a chance

01:15:08.360 | to look at what our own core and mantle is like

01:15:12.160 | or at least would be like

01:15:13.760 | if it had been also floating through space

01:15:15.720 | for a few billion years and getting irradiated and all that.

01:15:20.080 | But it's a cool potential window

01:15:22.920 | or like analogy into the interior of our own planet.

01:15:26.440 | - Well, how do you begin studying some of these asteroids?

01:15:29.640 | If you were to put together a study,

01:15:32.800 | what are the interesting questions to ask

01:15:35.520 | that are a little bit more specific?

01:15:37.000 | Like, do you find a favorite asteroid that could be tracked

01:15:40.800 | and try to track it through telescopes?

01:15:44.720 | Or do you, is it has to be,

01:15:47.960 | you have to land on those things to study it?

01:15:51.680 | - So when it comes to the asteroids,

01:15:53.720 | there are so many of them and the big pictures

01:15:56.520 | or the big questions are answered

01:16:03.280 | by the big picture.

01:16:04.120 | So some questions can be answered

01:16:05.920 | by zooming in in detail on individual object,

01:16:09.240 | but mostly you're trying to do a statistical study.

01:16:11.880 | So you wanna look at thousands of objects,

01:16:15.640 | even hundreds of thousands of objects

01:16:17.920 | and figure out what their composition is

01:16:21.440 | and look at how many big asteroids

01:16:25.600 | there are of this composition

01:16:26.880 | versus how many small asteroids of this other composition

01:16:29.240 | and put together these kind of statistical properties

01:16:32.840 | of the asteroid belt.

01:16:34.040 | And those properties can be directly compared

01:16:36.960 | with the results of simulations

01:16:39.120 | for the formation of the solar system.

01:16:41.360 | - What do we know about the surfaces of asteroids

01:16:44.640 | or the contents of the insides of asteroids

01:16:49.240 | and what are still open questions?

01:16:52.840 | - So I would say that we don't know a whole lot

01:16:56.720 | about their compositions.

01:16:59.800 | Most of them are small

01:17:01.000 | and so you can't study them in such detail with telescopes

01:17:06.000 | as you could a planet or moon.

01:17:08.640 | And at the same time, because there are so many of them,

01:17:11.400 | you could send a spacecraft to a few,

01:17:13.880 | but you can't really like get a statistical survey

01:17:17.280 | with spacecraft.

01:17:18.160 | And so a lot of what has been done

01:17:22.240 | comes down to sort of classification.

01:17:23.960 | You look at how bright they are,

01:17:25.880 | you look at whether they're red or blue,

01:17:30.200 | simply whether their spectrum is sloped

01:17:32.600 | towards long wavelengths or short wavelengths.

01:17:34.840 | There are certain,

01:17:36.080 | if you point a spectrograph at their surfaces,

01:17:40.600 | there are certain features you can see.

01:17:42.040 | So you can tell that some of them have silicates on them.

01:17:44.880 | But these are the sort of,

01:17:48.440 | they're pretty basic questions.

01:17:49.800 | We're still trying to classify them

01:17:51.360 | based on fairly basic information

01:17:54.000 | in kind of combination with our general understanding

01:17:56.960 | of the material the solar system formed from.

01:17:59.240 | And so you're sort of,

01:18:00.520 | you're coming in with prior knowledge,

01:18:02.320 | which is that you more or less know what the materials are

01:18:04.600 | the solar system formed from,

01:18:05.720 | and then you're trying to classify them

01:18:07.560 | into these categories.

01:18:09.120 | There's still a huge amount of room

01:18:12.400 | for understanding them better

01:18:14.760 | and for understanding how their surfaces are changing

01:18:18.240 | in the space environment.

01:18:19.920 | - Is it hard to land on an asteroid?

01:18:22.840 | Is this a dumb question?

01:18:25.840 | It feels like it would be quite difficult

01:18:30.320 | to actually operate a spacecraft

01:18:33.480 | in such a dense field of debris.

01:18:37.480 | - Oh, the asteroid belt,

01:18:41.000 | there's a ton of material there,

01:18:42.520 | but it's actually not that dense.

01:18:43.840 | It is mostly open space.

01:18:45.480 | - Okay.

01:18:46.320 | - So mentally do picture like mostly open space

01:18:49.240 | with some rocks.

01:18:51.200 | - The problem is some of them are not thought to be solid.

01:18:54.600 | So some of these asteroids,

01:18:55.680 | especially these core mantle fragments,

01:18:57.960 | you can think of as sort of solid like a planet,

01:19:00.560 | but some of them are just kind of aggregates of material.

01:19:04.480 | We call them rubble piles.

01:19:06.560 | And so there's not necessarily-

01:19:08.680 | - Might look like a rock,

01:19:10.800 | but do a lot of them have kind of clouds around them,

01:19:15.120 | like a dust cloud thing,

01:19:17.000 | or like, do you know what you're stepping on

01:19:19.960 | when you try to land on it?

01:19:21.360 | Like, what are we supposed to be visualizing here?

01:19:26.200 | This is like very few have water, right?

01:19:28.920 | - There's some water in the outer part of the asteroid belt,

01:19:31.200 | but they're not quite like comets.

01:19:33.640 | - Okay.

01:19:34.480 | - In the sense of having clouds around them.

01:19:37.200 | There are some crazy asteroids

01:19:39.280 | that do become active like comets.

01:19:41.000 | That's the whole other category of thing

01:19:43.400 | that we don't understand.

01:19:44.680 | But their surfaces, I mean, we have visited some,

01:19:48.120 | you can find pictures that spacecraft have taken of them.

01:19:51.160 | And we've actually scooped up material

01:19:52.680 | off of the surface of some of these objects.

01:19:54.600 | We're bringing it back to analyze it in the lab.

01:19:58.560 | And there's a mission that's launching next year

01:20:01.520 | to land on one of these supposedly core fragment objects

01:20:05.560 | to try to figure out what the heck it is

01:20:08.160 | and what's going on with it.

01:20:10.000 | But the surfaces, you can picture a solid surface

01:20:15.840 | with some little grains of sand or pebbles on it

01:20:19.080 | and occasional boulders, maybe some fine dusty regions,

01:20:23.960 | dust kind of collecting in certain places.

01:20:26.240 | - Do you worry about this?

01:20:30.440 | Is there any chance that one of these fellas

01:20:35.440 | destroys all of human civilization

01:20:37.920 | by an asteroid kind of colliding with something,

01:20:42.920 | changing its trajectory

01:20:44.360 | and then heading its way towards earth?

01:20:46.360 | - That is definitely possible.

01:20:49.280 | And it doesn't even have to necessarily collide with something

01:20:52.480 | and change its trajectory.

01:20:54.120 | We're not tracking all of them.

01:20:55.960 | We can't track all of them yet.

01:20:57.800 | You know, there's still-

01:20:59.040 | - A lot of them.

01:21:01.680 | - People are tracking a lot of them

01:21:03.600 | and we are doing our best to track more of them.

01:21:05.440 | But there are a lot of them out there

01:21:06.800 | and it would be potentially catastrophic

01:21:09.360 | if one of them impacted earth.

01:21:12.960 | - Are you aware of this Apophis object?

01:21:16.880 | So there's an asteroid, a near earth object called Apophis

01:21:20.760 | that people thought had a decent probability

01:21:23.800 | of hitting earth in 2029

01:21:26.880 | and then potentially again in 2036.

01:21:28.760 | So they did a lot of studies.

01:21:29.800 | It's not actually going to hit earth

01:21:31.720 | but it is going to come very close.

01:21:34.960 | It's gonna be visible in the sky in a relatively dark,

01:21:38.680 | I mean, not even that dark,

01:21:40.440 | probably not visible from Los Angeles.

01:21:42.760 | And it's gonna come a 10th of the way

01:21:49.560 | between the earth and the moon.

01:21:51.680 | It's gonna come closer apparently

01:21:53.280 | than some geosynchronous communication satellites.

01:21:56.120 | - Oh, wow.

01:21:56.960 | - So that is a close call, but people have studied it

01:22:00.680 | and then apparently are very confident

01:22:02.640 | it's not actually going to hit us, but it wasn't.

01:22:04.400 | - I'm gonna have to look into this

01:22:05.400 | 'cause I'm very sure, I'm very sure

01:22:08.240 | what's gonna happen if an asteroid actually hits earth

01:22:11.560 | that the scientific community and government

01:22:17.040 | will confidently say that we have nothing to worry about.

01:22:23.360 | It's going to be a close call.

01:22:26.240 | And then last minute, they'll be like,

01:22:28.120 | there was a miscalculation.

01:22:30.280 | They're not lying.

01:22:31.280 | It's just like the space of possibilities

01:22:34.040 | 'cause it's very difficult to track these kinds of things.

01:22:36.480 | And there's a lot of kind of,

01:22:38.840 | there's complexities involved to this.

01:22:40.400 | There's a lot of uncertainties.

01:22:41.960 | That I just, something tells me

01:22:44.360 | that human civilization will end with,

01:22:47.440 | we'll see it coming.

01:22:49.400 | And then last minute there'll be a oops.

01:22:52.600 | Well, like we'll see it coming and we'll be like,

01:22:54.480 | no, this is threatening, but no problem, no problem.

01:22:58.320 | And last minute it'll be like, oops,

01:22:59.720 | that was a miscalculation.

01:23:01.000 | And then it's all over in a matter of like a week.

01:23:05.480 | - But is there, (laughs)

01:23:07.840 | we're just very positive and optimistic today.

01:23:10.320 | Is there any chance that Bruce Willis can save us?

01:23:13.560 | In the sense that from what you know about asteroids,

01:23:17.240 | is there something that you can catch them early enough

01:23:22.240 | to change volcanic eruptions, right?

01:23:27.440 | Sort of drill, put a nuclear weapon inside

01:23:31.680 | and break up the asteroid or change its trajectory?

01:23:36.300 | - There is potential for that.

01:23:38.860 | If you catch it early enough in advance,

01:23:41.980 | I think in theory, if you knew five years in advance,

01:23:48.140 | depending on the objects and how close,

01:23:55.020 | how much you would need to deflect it,

01:23:57.780 | you could deflect it a little bit.

01:24:00.700 | I don't know that it would be sufficient in all cases.

01:24:04.260 | And this is definitely not my specific area of expertise,

01:24:08.180 | but my understanding is that

01:24:10.220 | there is something you could do.

01:24:12.540 | But it also, how you would carry that out

01:24:15.380 | depends a lot on the properties of the asteroid.

01:24:17.540 | If it's a solid object versus a rubble pile.

01:24:20.160 | So let's say you planted some bomb in the middle of it

01:24:24.380 | and it blew up,

01:24:26.460 | but it was just kind of a pile of material anyway.

01:24:28.860 | And then that material comes back together

01:24:30.700 | and then you kind of just have the same thing.

01:24:33.300 | Presumably its trajectory would be altered, but it's-

01:24:37.220 | - It's like Terminator 2,

01:24:38.460 | when it's like the thing that just like,

01:24:40.420 | you shoot it and it splashes and then comes back together.

01:24:43.180 | It would be very useless.

01:24:44.780 | That's fascinating.

01:24:45.620 | And what's fascinating,

01:24:47.020 | I've gotten a lot of hope

01:24:50.660 | from watching SpaceX rockets that land.

01:24:56.660 | There's so much, it's like, oh wow,

01:24:59.020 | from an AI perspective, from a robotics perspective,

01:25:02.780 | wow, we can do a hell of an amazing job with control.

01:25:07.580 | But then we have an understanding about surfaces here

01:25:13.500 | on earth, we can map up a lot of things.

01:25:15.940 | I wonder if we can do that some kind of detail

01:25:18.980 | of being able to have that same level of precision

01:25:22.900 | in landing on surfaces

01:25:25.020 | with as wide of a variety as asteroids have.

01:25:29.020 | So be able to understand

01:25:30.500 | the exact properties of the surface

01:25:33.220 | and be able to encode that

01:25:34.980 | into whatever rocket that lands sufficiently to,

01:25:37.740 | I presume humans, unlike the movies,

01:25:41.460 | humans would likely get in the way.

01:25:44.620 | Like it should all be done by robots.

01:25:47.220 | And like land, drill, place the explosive,

01:25:52.220 | that should all be done through control, through robots.

01:25:56.420 | And then you should be able to dynamically adjust

01:25:59.940 | to the surface.

01:26:01.020 | The flip side of that for a robotics person,

01:26:04.220 | I don't know if you've seen these,

01:26:05.340 | it's been very heartbreaking.

01:26:07.020 | Somebody I know well, Russ Tedrick at MIT

01:26:10.940 | led the DARPA Robotics Challenge Team

01:26:13.900 | for the Humanoid Robot Challenge.

01:26:15.540 | For DARPA, I don't know if you've seen videos

01:26:17.020 | of robots on two feet falling,

01:26:19.420 | but you're talking about millions,

01:26:21.540 | several years of work

01:26:23.060 | with some of the most brilliant roboticists in the world,

01:26:25.780 | millions of dollars.

01:26:26.900 | And the final thing is a highlight video on YouTube

01:26:29.420 | of robots falling,

01:26:30.620 | but they had a lot of trouble with uneven surfaces.

01:26:33.700 | That's basically what you have to do.

01:26:35.140 | With the challenge involves,

01:26:37.300 | you're mostly autonomous

01:26:38.500 | with some partial human communication,

01:26:41.140 | but that human communication is broken up.

01:26:43.180 | Like you don't get a, you get a noisy channel.

01:26:46.020 | So you can, humans can,

01:26:47.380 | which is very similar to what it would be like

01:26:50.740 | in humans remotely operating a thing on an asteroid.

01:26:54.740 | And so with that, robots really struggle.

01:26:57.240 | There's some hilarious, painful videos of like a robot,

01:27:00.940 | not able to like open the door.

01:27:03.220 | And then it tries to open the door without like,

01:27:05.580 | it misses the handle.

01:27:06.620 | And in doing so like falls.

01:27:09.220 | I mean, it's painful to watch.

01:27:11.940 | So like that, there's that, and then there's SpaceX.

01:27:15.540 | So I have hope from SpaceX,

01:27:17.740 | and then I have less hope from Bipedal Robotics.

01:27:20.200 | But it's fun to kind of imagine.

01:27:23.740 | And I think the planetary side of it comes into play

01:27:26.980 | in understanding the surfaces of these asteroids

01:27:28.980 | more and more that, you know,

01:27:31.780 | forget sort of destruction of human civilization.

01:27:34.460 | It'd be cool to have like spacecraft

01:27:36.380 | just landing on all these asteroids to study them at scale

01:27:40.340 | and being able to figure out dynamically what, you know,

01:27:43.580 | whether it's a rubble pile or whether it's a solid objects.

01:27:48.580 | Dick, do you see that kind of future of science,

01:27:51.460 | maybe 100, 200, 300 years from now,

01:27:53.780 | where there's just robots expanding out

01:27:57.740 | through the solar system, like sensors essentially.

01:28:00.620 | Some of it taking pictures from a distance,

01:28:02.320 | some of them landing, just exploring and giving us data.

01:28:05.180 | 'Cause it feels like we're working

01:28:06.260 | with very little data right now.

01:28:07.860 | - Sure, I do see exploration going that way.

01:28:14.460 | I think the way that NASA is currently,

01:28:19.460 | or historically has been doing missions

01:28:23.340 | is putting together these really large missions

01:28:26.460 | that do a lot of things and are extremely well tested

01:28:28.900 | and have a very low rate of failure.

01:28:30.360 | But now that these sort of CubeSat technologies

01:28:35.360 | are becoming easier to build, easier to launch,

01:28:39.900 | they're very cheap.

01:28:41.460 | And you know, NASA is getting involved in this as well.

01:28:43.820 | There's a lot of interest in these missions

01:28:46.900 | that are relatively small, relatively cheap

01:28:49.380 | and just do one thing.

01:28:50.480 | So you can really optimize it to just do this one thing

01:28:54.140 | and maybe you could build a hundred of them

01:28:55.660 | and send them to different asteroids.

01:28:57.140 | And they would just collect this one piece of information

01:28:59.360 | from each asteroid.

01:29:01.060 | It's a kind of different,

01:29:02.540 | more distributed way of doing science, I guess.

01:29:06.320 | And there's a ton of potential there, I agree.

01:29:09.160 | - Let me ask you about objects or one particular object

01:29:14.780 | from outside our solar system.

01:29:17.100 | We don't get to study many of these, right?

01:29:19.580 | We don't get stuff that just flies in out of nowhere

01:29:23.260 | from outside the solar system and flies through.

01:29:25.860 | Apparently there's been two recently in the past few years.

01:29:30.220 | One of them is Amuamua.

01:29:32.980 | What are your thoughts about Amuamua?

01:29:37.200 | So fun to say.

01:29:38.180 | Could it be space junk from a distant alien civilization

01:29:42.940 | or is this just a weird shaped comet?

01:29:47.840 | - I like the way that's phrased.

01:29:49.440 | So Amuamua is a fascinating object.

01:29:53.480 | Just the fact that we have started discovering things

01:29:56.300 | that are coming in from outside our solar system is amazing

01:29:59.640 | and can start to study them.

01:30:01.960 | And now that we have seen some,

01:30:03.760 | we can design now kind of thinking in advance.

01:30:08.760 | The next time we see one, we will be much more ready for it.

01:30:11.980 | We will know which telescopes we want to point at it.

01:30:14.100 | We will have explored whether we could even

01:30:16.540 | launch a fast turnaround mission to actually like get to it

01:30:20.140 | before it leaves the solar system.

01:30:22.100 | In terms of Amuamua, yeah,

01:30:25.280 | for an object in our solar system,

01:30:28.300 | it's really unusual in two particular ways.

01:30:32.740 | One is the dimensions that we don't see natural things

01:30:37.020 | in our solar system that are kind of long and skinny.

01:30:40.460 | The things we see in our solar system

01:30:41.700 | don't deviate from spherical by that much.

01:30:45.180 | And then that it showed these strange properties

01:30:48.420 | of accelerating as it was leaving the solar system,

01:30:51.060 | which was not understood at first.

01:30:53.220 | So in terms of the alien space junk,

01:30:58.220 | you know, as a scientist, I cannot rule out that possibility.

01:31:03.220 | I have no evidence to the contrary.

01:31:05.500 | However--

01:31:07.980 | - So you're saying there's a chance.

01:31:10.620 | - I cannot, as a scientist, honestly say

01:31:14.100 | that I can rule out that it's alien space junk.

01:31:17.340 | However, I see the kind of alien explanation

01:31:22.340 | as following this, the Sagan's extraordinary claims

01:31:27.340 | require extraordinary evidence.

01:31:29.080 | If you are going to actually claim that something is aliens,

01:31:33.780 | you need to carefully evaluate,

01:31:37.140 | one needs to carefully evaluate the other options

01:31:39.900 | and see whether it could just be something

01:31:43.300 | that we know exists that makes sense.

01:31:45.140 | In the case of a muamua,

01:31:46.660 | there are explanations that fit well

01:31:51.580 | within our understanding of how things work.

01:31:54.340 | So there are a couple, there are two hypotheses

01:31:58.100 | for what it could be made of.

01:31:59.220 | They're both basically just ice shards.

01:32:02.080 | In one case, it's a nitrogen ice shard

01:32:04.060 | that came off of something like Pluto

01:32:05.580 | in another solar system.

01:32:07.380 | That Pluto got hit with something and broke up into pieces.

01:32:10.640 | And one of those pieces came through our solar system.

01:32:13.220 | In the other scenario, it's a bit of a failed solar system.

01:32:18.220 | So our solar system formed out

01:32:21.100 | of a collapsing molecular cloud.

01:32:24.340 | Sometimes those molecular clouds are not massive enough

01:32:26.940 | and they sort of collapse into bits,

01:32:29.620 | but they don't actually form a solar system,

01:32:31.460 | but you end up with these kind of chunks

01:32:33.180 | of hydrogen ice apparently.

01:32:34.980 | And so one of those chunks of hydrogen ice

01:32:37.660 | could have got ejected and passed through our solar system.

01:32:39.700 | So both cases explain these properties

01:32:44.220 | in about the same way.

01:32:45.600 | So those ices will sublimate once they've passed the sun.

01:32:49.780 | And so as they're moving away from the sun,

01:32:51.380 | you have the hydrogen or nitrogen ice sublimating

01:32:53.880 | off the sunward part of it.

01:32:55.820 | And so that is responsible for the acceleration.

01:32:58.820 | The shape also, because you have all this ice

01:33:01.860 | sublimating off the surface,

01:33:04.160 | if you take something,

01:33:05.500 | the analogy that works pretty well here

01:33:09.700 | is for a bar of soap.

01:33:11.100 | Your bar of soap starts out sort of close to spherical,

01:33:14.300 | at least from a physicist's perspective.

01:33:16.740 | And as you use it over time,

01:33:18.580 | you eventually end up with this long thin shard

01:33:21.180 | because it's been just by sort of weathering,

01:33:24.340 | as we would call it.

01:33:25.340 | And so in the same way,

01:33:28.860 | if you just sublimate material

01:33:30.660 | off of one of these ice shards,

01:33:32.260 | it ends up long and thin

01:33:34.000 | and it ends up accelerating out of the solar system.

01:33:36.900 | And so given that these properties

01:33:38.380 | can be reasonably well explained that way,

01:33:40.480 | we should be extremely skeptical

01:33:45.260 | about attributing things to aliens.

01:33:48.940 | - See, the reason I like to think that it's aliens

01:33:52.040 | is because it puts a lot of priority

01:33:54.060 | on us not being lazy.

01:33:56.100 | And we need to catch this thing

01:33:58.380 | next time it comes around.

01:34:00.060 | I like the idea that there's objects,

01:34:01.940 | not like, it almost saddens me.

01:34:05.080 | They come out of the darkness really fast

01:34:07.600 | and just fly by and go and leave.

01:34:09.700 | It just seems like a wasted opportunity not to study them.

01:34:13.420 | It's like, it's the easiest way

01:34:18.000 | to do space travel outside of the solar system,

01:34:21.680 | is having the things come to us, right?

01:34:24.200 | - I like that way of putting it.

01:34:25.440 | - And it would be nice to just land on it.

01:34:27.560 | And first of all, really importantly,

01:34:31.060 | detect it early and then land on it

01:34:34.280 | with a really nice spacecraft and study the hell out of it.

01:34:40.960 | If there's a chance it's aliens, alien life,

01:34:50.840 | it just feels like such a cheap way, inexpensive way

01:34:56.920 | to get information about alien life

01:35:00.660 | or something interesting that's out there.

01:35:03.080 | And I'm not sure if a nice shard

01:35:04.380 | from another planetary system will be interesting,

01:35:08.120 | but it very well could be.

01:35:09.480 | It could be totally new sets of materials.

01:35:11.400 | It could tell us about composition

01:35:13.440 | of planets we don't quite understand.

01:35:16.540 | And it's just nice when,

01:35:17.540 | especially in the case of a MoMo,

01:35:19.040 | I guess it was pretty close to Earth.

01:35:20.920 | It would have been nice to, you know,

01:35:23.880 | let's say, don't go there, they come to us.

01:35:27.360 | I don't know.

01:35:28.440 | That's what makes me quite a sad.

01:35:31.380 | It's a missed opportunity.

01:35:33.180 | - Well, yeah.

01:35:34.020 | And whether you think it's aliens or not,

01:35:36.380 | it's a missed opportunity, but, you know,

01:35:38.820 | we weren't prepared and we will be prepared

01:35:40.700 | for the next ones.

01:35:41.780 | And as so there's been a movement in astronomy

01:35:46.660 | more towards what's called time domain astronomy.

01:35:49.080 | So kind of monitoring the whole sky all the time

01:35:52.120 | at all wavelengths, that's kind of the goal.

01:35:53.860 | And so we expect to detect many more of these in the future,

01:35:57.280 | even though these were the first two we saw,

01:35:59.340 | our potential to detect them is only increasing with time.

01:36:01.980 | And so there will be more opportunities.

01:36:04.560 | And, you know, based on these two,

01:36:06.860 | we now can actually sit and think about what we'll do

01:36:10.360 | when the next one shows up.

01:36:11.860 | - I also, what it made me realize,

01:36:13.860 | I know I didn't really think through this,

01:36:15.900 | but it made me realize

01:36:17.860 | if there is alien civilizations out there,

01:36:20.520 | the thing we're most likely to see first

01:36:22.940 | would be space junk.

01:36:24.580 | My stupid understanding of it.

01:36:28.220 | And the second would be really dumb kind of,

01:36:31.060 | you could think of maybe like relay nodes or something,

01:36:35.640 | objects that you need to have a whole lot of

01:36:40.220 | for particular purposes of like space travel and so on,

01:36:44.120 | like speed limit signs or something, I don't know,

01:36:46.500 | whatever we have on earth, a lot of, that's dumb.

01:36:49.940 | It's not aliens in themselves.

01:36:52.500 | It's like artifacts that are useful to the engineering

01:36:56.240 | in the systems that are engineered by alien civilizations.

01:36:59.200 | So like, we would see a lot of stuff.

01:37:03.920 | In terms of SETI, in terms of looking for alien life

01:37:06.280 | and trying to communicate with it,

01:37:07.760 | maybe we should be looking not for like smart creatures

01:37:12.760 | or systems to communicate with.

01:37:17.280 | Maybe we should be looking for artifacts

01:37:20.840 | or even as dumb as like space junk.

01:37:24.000 | It just kind of reframed my perspective of like,

01:37:26.980 | what are we looking for as signs?

01:37:28.980 | 'Cause there could be a lot of stuff

01:37:31.740 | that doesn't have intelligence

01:37:33.060 | but gives us really strong signs

01:37:34.620 | that there's somewhere is life or intelligent life.

01:37:37.640 | And yeah, that made me kind of,

01:37:40.780 | I know it might be dumb to say it,

01:37:42.980 | but reframe the kind of thing that we should be looking for.

01:37:46.140 | - Yeah, it's, so the benefit of looking

01:37:50.380 | for intelligent life is that we perhaps

01:37:52.380 | have a better chance of recognizing it.

01:37:54.500 | - Yeah. - We couldn't necessarily

01:37:57.220 | recognize what an alien stop sign looked like.

01:37:59.580 | - That's true. - And maybe,

01:38:02.380 | the theorists or the people who sort of model

01:38:05.080 | and try to understand solar system objects

01:38:07.620 | are pretty good at coming up with models for anything.

01:38:10.220 | I mean, maybe a muamua was a stop sign,

01:38:12.780 | but we're clever enough that we could come up

01:38:15.580 | with some physical explanations for it.

01:38:18.140 | And then, we all wanna go with the simplest possible,

01:38:21.340 | we all wanna believe the sort of most skeptical

01:38:24.500 | possible explanation.

01:38:25.540 | And so we missed it because we're too good

01:38:27.260 | at coming up with alternate explanations for things.

01:38:30.100 | - And it's such an outlier, such a rare phenomenon

01:38:32.660 | that we can't study 100 or a thousand of these objects.

01:38:36.660 | We have to, we had just one.

01:38:38.100 | And so the science almost destroys the possibility

01:38:42.260 | of something special being there.

01:38:43.740 | It's like a Johnny Ive, this designer of Apple,

01:38:46.820 | I don't know if you know who that is.

01:38:48.340 | He's the lead designer.

01:38:49.380 | He's the person who designed the iPhone

01:38:51.660 | and all the major things.

01:38:53.580 | And he talked about, he's brilliant,

01:38:55.740 | one of my favorite humans on earth

01:38:57.580 | and one of the best designers in the history of earth.

01:39:01.120 | He talked about like when he had this origins of an idea,

01:39:05.460 | like in his baby stages, he would not tell Steve Jobs

01:39:08.660 | because Steve would usually like trample all over it.

01:39:11.820 | He would say, "This is a dumb idea."

01:39:13.980 | And so I sometimes think of the scientific community

01:39:16.020 | in that sense because the weapon of the scientific method

01:39:21.020 | is so strong at its best that it sometimes crushes

01:39:26.060 | the out of the box outlier evidence.

01:39:30.300 | You know, we don't get a lot of that evidence

01:39:32.400 | 'cause we don't have, we're not lucky enough

01:39:34.880 | to have a lot of evidence.

01:39:35.880 | So we have to deal with just special cases.

01:39:38.740 | And special cases could present an inkling

01:39:41.860 | of something much bigger.

01:39:44.420 | But the scientific method user tramples all over it.

01:39:46.780 | And it's hard to know what to do with that

01:39:49.180 | because the scientific method works.

01:39:52.080 | But at the same time, every once in a while,

01:39:53.860 | it's like a balance.

01:39:55.180 | You have to do 99% of the time,

01:39:56.960 | you have to do like scientific rigor.

01:39:59.660 | But every once in a while, this is not you saying,

01:40:01.620 | me saying, smoke some weed and sit back and think,

01:40:05.940 | "I wonder," you know, it's the Joe Rogan thing.

01:40:09.200 | It's entirely possible that it's alien space junk.

01:40:14.460 | Anyway.

01:40:15.300 | - Yeah, I think, so I completely agree.

01:40:18.300 | And I think that most scientists

01:40:21.460 | do speculate about these things.

01:40:23.460 | It's just, at what point do you act on those things?

01:40:27.120 | So you're right that the scientific method

01:40:30.620 | has inherent skepticism.

01:40:31.900 | And for the most part, that's a good thing

01:40:35.500 | because it means that we're not just believing

01:40:38.320 | crazy things all the time.

01:40:41.180 | But it's an interesting point

01:40:45.020 | that requiring that high level of rigor

01:40:49.140 | occasionally means that you will miss something

01:40:52.340 | that is truly interesting

01:40:54.180 | because you needed to verify it three times

01:40:57.260 | and it wasn't verifiable.

01:40:58.700 | - I also think like when you communicate

01:41:00.380 | with the general public,

01:41:02.440 | I think there's power in that 1% speculation

01:41:05.220 | of just demonstrating authenticity as a human being,

01:41:09.980 | as a curious human being.

01:41:11.340 | I think too often, I think this is changing,

01:41:15.740 | but I saw, I've been quite disappointed in my colleagues

01:41:19.740 | throughout 2020 with the coronavirus.

01:41:22.980 | There's too much speaking from authority

01:41:25.100 | as opposed to speaking from curiosity.

01:41:28.840 | There's some of the most incredible science

01:41:30.380 | that's been done in 2020,

01:41:31.740 | especially on the virology, biology side.

01:41:34.580 | And the kind of being talked down to by scientists

01:41:39.540 | is always really disappointing to me

01:41:41.420 | as opposed to inspiring.

01:41:43.300 | Like the things we,

01:41:44.260 | there's a lot of uncertainty about the coronavirus,

01:41:46.940 | but we know a lot of stuff.

01:41:48.780 | And we speak from scientists from various disciplines,

01:41:52.180 | speak from data in the face of that uncertainty.

01:41:56.160 | And we're curious, we don't know what the hell is going on.

01:41:58.660 | We don't know if this virus is going to evolve, mutate.

01:42:02.580 | We don't know if this virus or the next one

01:42:05.100 | might destroy all of human civilization.

01:42:07.740 | You can't speak with certain,

01:42:08.900 | in fact, I was on a survey paper about masks.

01:42:13.560 | Something I don't talk much about

01:42:16.060 | 'cause I don't like politics,

01:42:18.060 | but we don't know if masks work,

01:42:20.940 | but there's a lot of evidence to show that they work

01:42:23.140 | for this particular virus.

01:42:24.100 | The transmission of the virus is fascinating actually.

01:42:26.820 | The biomechanics of the way viruses spread is fascinating.

01:42:31.820 | If it wasn't destructive, it would be beautiful.

01:42:36.100 | And we don't know,

01:42:36.980 | but it's inspiring to apply the scientific method

01:42:40.580 | to the best of our ability,

01:42:42.080 | but also to show that you don't always know everything

01:42:44.900 | and to, perhaps not about the virus as much,

01:42:47.760 | but other things speculate.

01:42:50.840 | What if?

01:42:51.680 | What if it's the worst case and the best case?

01:42:56.140 | Because that's ultimately what we are,

01:42:58.700 | descendants of apes that are just curious

01:43:00.300 | about the world around us.

01:43:02.300 | - Yeah, I'll just add to that,

01:43:04.860 | not on the topic of masks, but on the topic of curiosity.

01:43:08.100 | That's, I mean, I think that's,

01:43:13.100 | astronomy and planetary sciences field are a little,

01:43:18.580 | are unique because for better and for worse,

01:43:21.940 | they don't directly impact humanity.

01:43:24.980 | So, we're not studying virology to prevent transmission

01:43:31.100 | of illness amongst humans.

01:43:35.380 | We're not characterizing volcanoes on earth

01:43:38.700 | that could destroy cities.

01:43:40.500 | And it really is a more curious and in my opinion,

01:43:45.380 | playful scientific field than many.

01:43:47.840 | So, for better and worse,

01:43:50.740 | we can kind of afford to pursue some of the speculation more

01:43:53.900 | because human lives are not in danger

01:43:56.780 | if we speculate a little bit too freely

01:43:59.300 | and get something wrong.

01:44:01.220 | - Yeah, definitely.

01:44:02.220 | In the space of AI, I am worried

01:44:05.500 | that we're sometimes too eager, speaking for myself,

01:44:09.940 | to flip the switch to on just to see what happens.

01:44:14.780 | Maybe sometimes we wanna be a little bit careful about that

01:44:17.700 | 'cause bad things might happen.

01:44:19.640 | Is there books or movies in your life long ago or recently

01:44:25.300 | that were inspiring, had an impact on you

01:44:28.800 | that you would recommend?

01:44:30.380 | - Yeah, absolutely.

01:44:31.780 | So many that I just don't know where to start with it.

01:44:34.640 | So, I love reading.

01:44:37.220 | I read obsessively.

01:44:38.380 | I've been reading fiction and a little bit of nonfiction,

01:44:41.660 | but mostly fiction obsessively since I was a child

01:44:45.300 | and just never stopped.

01:44:46.460 | So, I have some favorite books.

01:44:50.080 | None of them are easy readings.

01:44:51.780 | So, I definitely, I mean, I recommend them for somebody

01:44:54.700 | who likes an intellectual challenge

01:44:56.660 | in the books that they read.

01:44:59.860 | So, maybe I should go chronologically.

01:45:02.940 | I have at least three.

01:45:04.340 | I'm not gonna go through 50 here, but.

01:45:07.860 | - Yeah, I'd love to also,

01:45:09.900 | like maybe ideas that you took away from what you mentioned.

01:45:14.900 | - Yeah, yeah, why they were so compelling to me.

01:45:17.880 | One of the first books that really captured my fascination

01:45:23.480 | was Nabokov's book "Pale Fire."

01:45:26.380 | - Oh, wow.

01:45:27.540 | - Are you familiar with it?

01:45:29.140 | - So, I read it actually for a class.

01:45:34.140 | It's one of the few books I've ever read for a class

01:45:36.520 | that I actually really liked.

01:45:37.920 | And the book is, it's in some sense a puzzle.

01:45:44.360 | He's a brilliant writer, of course,

01:45:47.060 | but the book is like, it's formatted like a poem.

01:45:52.060 | So, there's an introduction, a very long poem and footnotes,

01:45:56.940 | and you get partway through it before realizing

01:46:00.620 | that the whole thing is actually a novel,

01:46:03.140 | unless you sort of read up on it going in,

01:46:05.020 | but the whole thing is a novel,

01:46:06.540 | and there's a story that slowly reveals itself

01:46:10.420 | over the course of all of this,

01:46:12.300 | and kind of reveals this just fascinating character,

01:46:19.020 | basically, and how his mind works in this story.

01:46:23.960 | The idea of a novel also being a kind of intellectual puzzle

01:46:28.200 | and something that slowly reveals itself

01:46:31.100 | over the course of reading was really fascinating to me,

01:46:34.060 | and I have since found a lot more writers like that.

01:46:37.360 | Contemporary example that comes to mind is Kazuo Ishiguro,

01:46:43.260 | who's pretty much all of his books are slow reveals

01:46:46.620 | over the course of the book,

01:46:47.600 | and nothing much happens in the books,

01:46:50.200 | but you keep reading them because you just wanna know

01:46:53.340 | what the reality is that he's slowly revealing to you,

01:46:56.640 | the kind of discovery-oriented reading, maybe.

01:47:00.300 | - What's the second one?

01:47:03.720 | - Perhaps my favorite writer is Renier Maria Rilke.

01:47:08.720 | - Wow.

01:47:09.880 | - Are you familiar with him? - No, also not familiar.

01:47:13.060 | You're hitting the ones, I mean, I know in the book of well,

01:47:15.900 | but I've never read "Pale Fire," but Rilke, I've never,

01:47:19.500 | I know it's a very difficult read, I know that much.

01:47:22.580 | - Yeah, right, all of these are difficult reads.

01:47:25.260 | I think I just, I read in part for an intellectual challenge

01:47:30.260 | but Rilke, so he wrote one thing

01:47:34.580 | that might be characterizable as a novel,

01:47:36.760 | but he wrote a lot of poetry.

01:47:38.740 | I mean, he wrote this series of poems

01:47:40.600 | called "The Duino Elegies" that were very impactful for me

01:47:44.600 | personally, just emotionally,

01:47:48.460 | which actually, it kind of ties in with astronomy

01:47:53.100 | in that there's a sense,

01:47:57.780 | in which we're all going through our lives alone

01:48:01.420 | and there's just this sense of kind of profound loneliness

01:48:05.200 | in the existence of every individual human.

01:48:09.140 | And I think I was drawn to astronomy in part

01:48:13.840 | because the sort of vast spaces,

01:48:17.560 | the kind of loneliness and desolateness of space

01:48:21.420 | made the sort of internal loneliness feel okay,

01:48:24.560 | in a sense, it like gave companionship.

01:48:26.740 | That's how I feel about Rilke's poetry.

01:48:32.100 | He turns the kind of desolation and loneliness

01:48:37.100 | of human existence into something joyful

01:48:40.840 | and almost meaningful.

01:48:42.180 | - Yeah, there's something about melancholy,

01:48:45.900 | I don't know about Rilke in general,

01:48:47.200 | but like contemplating the melancholy nature

01:48:52.200 | of the human condition that makes it okay.

01:48:58.700 | Like I tend to, from an engineering perspective,

01:49:03.580 | think that there is so much loneliness

01:49:05.880 | we haven't explored within ourselves yet.

01:49:08.860 | And that's my hope is to build AI systems

01:49:12.020 | that help us explore our own loneliness.

01:49:15.560 | I think that's kind of what love is and friendship is,

01:49:18.520 | is somebody who in a very small way

01:49:21.780 | helps us explore our own loneliness.

01:49:24.080 | Like they listen, we connect like two lonely creatures

01:49:28.540 | connect for a time and it's like,

01:49:31.060 | oh, like acknowledge that we exist together

01:49:34.800 | like for a brief time.

01:49:37.380 | But in a somewhat shallow way,

01:49:39.440 | I think relative to how much it's possible

01:49:42.300 | to truly connect those two consciousnesses.

01:49:44.440 | So AI might be able to help on that front.

01:49:48.920 | So what's the third one?

01:49:50.000 | - Actually, I hadn't realized until this moment,

01:49:52.760 | but it's yet another one of these kind of slow reveal books.

01:49:56.960 | It's a contemporary Russian,

01:49:59.960 | I think Russian American writer named Olga Grushin,

01:50:03.280 | G-R-U-S-H-I-N.

01:50:05.400 | And she wrote this just phenomenal book

01:50:07.880 | called "The Dream Life of Sukhonov"

01:50:10.280 | that I read this year,

01:50:12.480 | maybe it was last year for the first time.

01:50:14.720 | And it's just a really beautiful,

01:50:16.940 | this one you could call a character study, I think,

01:50:20.900 | of a Russian father coming to terms with himself

01:50:26.160 | and his own past

01:50:27.480 | as he potentially slowly loses his mind.

01:50:32.680 | - Slow reveal.

01:50:35.280 | Slow reveal of love.

01:50:37.720 | - Well, that's apparent from the beginning.

01:50:39.760 | I hope I don't think it's a spoiler.

01:50:42.100 | (laughs)

01:50:43.300 | - Declining to madness, spoiler alert.

01:50:46.100 | - So all of these are really heavy.

01:50:47.540 | I don't know, I just,

01:50:48.620 | I don't have anything lighter to recommend.

01:50:50.580 | Ishiguro's the light version of this.

01:50:52.740 | - Okay.

01:50:53.580 | (laughs)

01:50:54.820 | Oh, well, heavy has a certain kind of beauty to it

01:50:57.540 | in itself.

01:50:58.380 | Is there advice you would give to a young person today

01:51:01.860 | that looks up to the stars

01:51:03.060 | and wonders what the heck they wanna do with their life?

01:51:05.020 | So career, science, life in general,

01:51:09.620 | you've for now chosen a certain kind of path of curiosity.

01:51:13.420 | What insights do you draw from that

01:51:17.100 | that you can give as advice to others?

01:51:19.000 | - I think for somebody,

01:51:21.900 | I would not presume to speak,

01:51:25.260 | to giving people advice on life and humanity overall,

01:51:29.140 | but for somebody thinking of being a scientist.

01:51:33.660 | So there are a couple of things,

01:51:35.740 | one sort of practical thing,

01:51:37.740 | which is career-wise,

01:51:40.100 | I hadn't appreciated this going into science,

01:51:42.260 | but you need to,

01:51:44.340 | so the questions you're working on

01:51:48.240 | and the techniques you use

01:51:50.660 | are both of very high importance,

01:51:54.320 | maybe equal importance for being happy in your career.

01:51:57.060 | If there are questions you're interested in,

01:51:59.620 | but the techniques that you need to use to do them

01:52:03.100 | are tedious for you,

01:52:04.460 | then your job is gonna be miserable,

01:52:06.620 | even if the questions are inspiring.

01:52:08.980 | So you have to find,

01:52:11.340 | but if the techniques that you use

01:52:13.060 | are things that excite you,

01:52:14.800 | then your job is fun every day.

01:52:16.620 | So for me, I'm fascinated by the solar system

01:52:19.060 | and I love telescopes

01:52:21.300 | and I love doing data analysis,

01:52:22.660 | playing with data from telescopes,

01:52:24.020 | coming up with new ways to use telescopes,

01:52:25.740 | and so that's where I have found that mesh.

01:52:28.040 | But if I was interested in

01:52:30.660 | the dynamical evolution of the solar system,

01:52:32.660 | how the orbits of things evolve,

01:52:34.020 | then I would need to do a different type of work

01:52:36.700 | that I would just not find as appealing

01:52:38.340 | and so it just wouldn't be a good fit.

01:52:39.740 | And so it's sort of is,

01:52:41.820 | seems like an unromantic thing

01:52:43.380 | to have to think about the techniques

01:52:45.120 | being the thing you wanna work on also,

01:52:46.560 | but it really makes a profound difference

01:52:49.260 | for I think your happiness in your scientific career.

01:52:52.380 | - I think that's really profound.

01:52:53.540 | It's like the thing, the menial tasks.

01:52:56.260 | If you enjoy those, that's a really good sign

01:52:58.060 | that that's the right path for you.

01:53:00.540 | I think David Foster Wallace said that

01:53:02.860 | the key to life is to be unboreable.

01:53:04.700 | So basically everything should be exciting.

01:53:09.820 | I don't think that's feasible,

01:53:11.640 | but you should find an area where everything is exciting.

01:53:15.300 | I mean, depending on the day,

01:53:16.460 | but you could find the joy in everything,

01:53:19.360 | not just the big exciting, quote unquote,

01:53:21.700 | things that everyone thinks is exciting,

01:53:23.620 | but the details, the repetitive stuff,

01:53:28.620 | the menial stuff, the stuff that takes years,

01:53:30.980 | the stuff that involves a lot of failure

01:53:32.980 | and all those kinds of things,

01:53:33.980 | and you find that enjoyable.

01:53:35.380 | That's actually really profound to focus on that

01:53:37.740 | 'cause people talk about like dreams and passion and goals

01:53:42.060 | and so on, the big thing,

01:53:43.180 | but that's not actually what takes you there.

01:53:44.540 | It takes you there every single day, putting in the hours,

01:53:48.100 | and that's what actually makes up life is the boring bits.

01:53:51.900 | And if the boring bits aren't boring,

01:53:54.060 | then that's an exciting life.

01:53:56.420 | - Let me, 'cause when you were talking so romantically

01:54:01.340 | and passionately about "I/O",

01:54:03.620 | I remember the poem by Robert Frost.

01:54:06.340 | So let me ask you, let me read the poem

01:54:08.860 | and ask what your opinion is.

01:54:11.380 | It's called "Fire and Ice".

01:54:12.860 | - Oh yeah, I could almost recite this from memory.

01:54:16.220 | - Some say the world will end in fire, some say in ice.

01:54:19.420 | From what I've tasted of desire,

01:54:20.980 | I hold with those who favor fire.

01:54:23.380 | But if I had to perish twice,

01:54:25.860 | I think I know enough of hate to say that for destruction,

01:54:29.180 | ice is also great and will suffice.

01:54:32.860 | So let me ask, if you had to only choose one,

01:54:37.860 | would you choose the world to end in fire,

01:54:41.280 | in volcanic eruptions, in heat and magma,

01:54:46.280 | or in ice frozen over?

01:54:49.380 | Fire or ice?

01:54:51.820 | - Fire.

01:54:53.100 | (laughing)

01:54:55.340 | - Excellent choice.

01:54:57.060 | - It's just the sort of,

01:54:58.420 | I've always been a fan of chaos

01:55:02.300 | and the idea of things just slowly getting cold

01:55:07.300 | and stopping and dying is just so depressing to me.

01:55:14.580 | So much more depressing than things blowing up

01:55:18.260 | or burning and getting covered by a lava flow.

01:55:21.180 | Somehow the activity of it endows it

01:55:24.180 | with more meaning to me, maybe.

01:55:27.580 | - I've just now had this vision of you,

01:55:29.260 | you know, in action films where you're walking away

01:55:31.620 | without looking back and there's explosions behind you

01:55:34.460 | and you put on shades and then it goes to credits.

01:55:37.540 | So, Katherine, this was awesome.

01:55:40.380 | I think your work is really inspiring.

01:55:43.440 | The kind of things we'll discover about planets

01:55:48.260 | in the next few decades is super cool

01:55:50.300 | and I hope, I know you said there's probably not life

01:55:53.900 | in one of them, but there might be.

01:55:55.540 | And I hope we discover just that.

01:55:58.020 | And perhaps even on Io, within the volcanic eruptions,

01:56:01.980 | there's a little creature hanging on

01:56:04.580 | that we'll one day discover.

01:56:06.220 | Thank you so much for wasting all your valuable time

01:56:08.460 | with me today.

01:56:09.300 | It was really awesome.

01:56:10.580 | - Yeah, likewise.

01:56:11.500 | Thank you for having me here.

01:56:13.060 | - Thanks for listening to this conversation

01:56:15.700 | with Katherine DeCleer.

01:56:16.940 | And thank you to Fundrise, Blinkist, ExpressVPN

01:56:21.260 | and Magic Spoon.

01:56:23.060 | Check them out in the description to support this podcast.

01:56:26.380 | And now let me leave you with some words from Carl Sagan.

01:56:29.580 | "On Titan, the molecules that have been raining down

01:56:32.220 | like mana from heaven for the last four billion years

01:56:35.860 | might still be there, largely unaltered, deep frozen,

01:56:40.020 | awaiting for the chemists from Earth."

01:56:42.660 | Thank you for listening and hope to see you next time.

01:56:45.340 | (upbeat music)

01:56:47.940 | (upbeat music)

01:56:50.540 | [BLANK_AUDIO]

Katherine de Kleer: Planets, Moons, Asteroids & Life in Our Solar System | Lex Fridman Podcast #184

Chapters