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Is there Uranium on Uranus? · Daniel and Kelly’s Extraordinary Universe

0:08
Speaker 1: Hey, Kelly, are you a fan of astronomy humor? It
0:13
Speaker 1: depends as long as we're not making jokes about urinus. Well,
0:17
Speaker 1: we'll have to try to avoid falling into that particular hole.
0:20
Speaker 1: But personally, I love a good astronomy pun. I have
0:24
Speaker 1: more of a plutonic relationship. Oh no, did you just
0:28
Speaker 1: make that joke up or did you have to plan it? Okay,
0:32
Speaker 1: I've got one for you. Alright. Why don't stars go
0:36
Speaker 1: to university? Alright? Why? Because they've already got millions of degrees.
0:44
Speaker 1: I'm sorry. Hi, I'm Daniel. I'm a particle physicist and
1:03
Speaker 1: a professor at UC Irvine, and I will always laugh
1:07
Speaker 1: at astronomy puns. Hi, I'm Kelly Weener Smith. I'm a
1:10
Speaker 1: parasitologist at Rice University, and I think my last name
1:14
Speaker 1: is hilarious. So I will always laugh at both parasitology
1:17
Speaker 1: puns and scatological humor. There's gotta be a lot of
1:20
Speaker 1: good puns when you're talking about worms and bugs and
1:23
Speaker 1: things that crawling inside other things. So and they get,
1:27
Speaker 1: but we try to keep this podcast family friendly, and
1:29
Speaker 1: so we will spare you most of those and so
1:32
Speaker 1: welcome to the podcast. Daniel and Jorgey explain the Universe,
1:36
Speaker 1: in which we talk about all the incredible and amazing
1:39
Speaker 1: things out there in the universe. We crack jokes about
1:42
Speaker 1: the silly names they get, but we have a deep,
1:44
Speaker 1: deep love for the mysteries of the universe and we
1:47
Speaker 1: want to explore all of them with you. We think
1:49
Speaker 1: it's incredible. It's amazing that this universe is understandable at
1:53
Speaker 1: all to our tiny human brains. We want to push
1:56
Speaker 1: forward this effort and bring this understanding of the universe
1:59
Speaker 1: into all of our minds because everybody out there has
2:02
Speaker 1: questions about how the universe works and wants to know
2:05
Speaker 1: where it came from and where it's going to go
2:06
Speaker 1: and how it all fits together. So thanks very much
2:09
Speaker 1: for joining us on our journey of curiosity. My typical
2:13
Speaker 1: co host Orge isn't with us today, and so we
2:15
Speaker 1: have are wonderful and hilarious and very punny co host Kelly.
2:21
Speaker 1: Thanks for joining us. Kelly, thanks for having me. I'm
2:23
Speaker 1: super excited about today's question. Awesome, And you know, on
2:27
Speaker 1: this podcast we often talk about things that are very
2:30
Speaker 1: far away. We're very distant in space and time, but
2:34
Speaker 1: we also have questions about things that happen in our backyard.
2:37
Speaker 1: We're very curious about the nature of our environment, how
2:41
Speaker 1: the Earth formed, how the Solar system formed, how it
2:43
Speaker 1: all came together. You have a very broad definition of
2:46
Speaker 1: in our backyard. That's true, I guess, parasitologist, when you
2:51
Speaker 1: talk about backyard, you mean literally like what's inside my fence, right,
2:56
Speaker 1: That's exactly what I mean. Cosmologically speaking, though, our backyard
3:00
Speaker 1: to me is like the stuff that formed with us,
3:03
Speaker 1: that has like a common history that we could like
3:05
Speaker 1: go and visit it and dig up something on an
3:07
Speaker 1: asteroid and from that learned something about the Earth. We
3:10
Speaker 1: have like answers in common, and actually later on in
3:13
Speaker 1: the episode, we're gonna hear a really cool story about
3:15
Speaker 1: how asteroids told us something about the history of our
3:19
Speaker 1: planet and how uranium was involved. But you might look
3:22
Speaker 1: at our planet and think, like, m it looks kind
3:24
Speaker 1: of different from the other planets. I mean, like, we have,
3:26
Speaker 1: for example, a nice surface, and we have water, and
3:29
Speaker 1: we have an atmosphere, and you know the Moon doesn't
3:31
Speaker 1: have that, and Jupiter and Saturn and Neptune and Urine
3:35
Speaker 1: is these planets all look very different from ours, and
3:37
Speaker 1: so you might wonder like did they form differently? Are
3:40
Speaker 1: they made of the same stuff? What do we really
3:42
Speaker 1: know about what's going on in the rest of the
3:43
Speaker 1: Solar System and how is it all connected? And so
3:47
Speaker 1: we thought a fun question to dig into would be
3:49
Speaker 1: to ask questions about what's going on inside these other
3:52
Speaker 1: big planets. That's a great question. I've been reading a
3:54
Speaker 1: bit about what is on the various different planets that
3:57
Speaker 1: I'm always surprised by, well by how much for lap
4:00
Speaker 1: there tends to be, but also the important things that
4:02
Speaker 1: seem to be missing, like carbon on the Moon. It's
4:05
Speaker 1: gonna be really hard to grow plants on the Moon
4:07
Speaker 1: with no carbon. Do you have plans to go plants
4:10
Speaker 1: on the Moon? I do not, but plenty of people do.
4:13
Speaker 1: Fun fact, the most concentrated carbon in the Moon is
4:17
Speaker 1: probably the bags of feces that the Apollo astronauts left behind.
4:21
Speaker 1: And this is why I don't get invited to parties.
4:25
Speaker 1: Are those frozen remains from the astronauts also useful because
4:29
Speaker 1: they contain like the microbiome of those astronauts from what
4:32
Speaker 1: they were eating like forty years ago. I don't think
4:35
Speaker 1: that microbiome is going to be useful for much anymore.
4:38
Speaker 1: But I also think that according to the Outer Space Treaty,
4:41
Speaker 1: those bags of feces technically still belong to NASA, So
4:46
Speaker 1: I guess it depends on what NASA wants to do
4:47
Speaker 1: with them. Well, if they've become an important resource, we
4:50
Speaker 1: could end up with an international or interstellar war sparked
4:54
Speaker 1: by astronaut remains. So why hasn't someone written about that
5:00
Speaker 1: massive lost opportunity? Contact us if you need book ideas, Guys,
5:05
Speaker 1: I'm sure somebody out there has written that science fiction
5:07
Speaker 1: story already. But we're not so interested in where astronauts
5:11
Speaker 1: have left their remains. Were interested in whether there are
5:14
Speaker 1: really big, heavy materials on other planets. Some of the
5:18
Speaker 1: most exotic, some of the most amazing, some of the
5:20
Speaker 1: weirdest things we find on Earth. We are wondering if
5:23
Speaker 1: they also exist on other planets. And so today we
5:26
Speaker 1: will be asking is there uranium on Uranus? Now? I
5:36
Speaker 1: notice you very carefully pronouncing the title of the planet Uranus. Yes,
5:40
Speaker 1: very carefully. I have a seven year old at home,
5:42
Speaker 1: and so I have to be careful to not edge
5:45
Speaker 1: anywhere near that word, otherwise I can't talk to her
5:49
Speaker 1: for about three hours because she's laughing too hard and
5:52
Speaker 1: me as well. But is there an option to pronounce
5:54
Speaker 1: uranium with the same rhythm, like could you say uranium
5:58
Speaker 1: your how you even say that uranium? Uran question? I've
6:02
Speaker 1: never thought about it. I don't know. Is there uranium
6:05
Speaker 1: on Uranus? Sorry, no, we got it backwards. Is there
6:11
Speaker 1: is there urinium? Is there uranium on Uranus? There we go,
6:17
Speaker 1: and the rest of the podcast would just be us giggling.
6:23
Speaker 1: Control yourself. But it is a serious scientific question whether
6:28
Speaker 1: uranium only exists on Earth, because you can imagine in
6:32
Speaker 1: the future, as we're exploring the Solar System, we might
6:34
Speaker 1: want to mind other planets for useful minerals as we're
6:38
Speaker 1: powering our spaceships out of the Solar System or even
6:41
Speaker 1: around the Solar System. And also to me, it's just
6:43
Speaker 1: a fun question to think about, first of all, how
6:45
Speaker 1: it was made in the universe and how it is
6:47
Speaker 1: distributed and where it ended up. You know, is the
6:49
Speaker 1: Earth unique in its collection of heavy metals or is
6:52
Speaker 1: maybe uranium like very common on Urinus and other planets.
6:56
Speaker 1: So I think the more than just a giggle factor.
6:58
Speaker 1: This is a serious sign diffic question, very serious, very serious. Yes,
7:03
Speaker 1: so putting on our serious faces. I went out there
7:05
Speaker 1: and I asked folks on the internet listeners to this
7:08
Speaker 1: show whether they thought there was uranium on Uranus. So,
7:12
Speaker 1: if you would like to participate for future rounds the
7:14
Speaker 1: podcast and like to play along at home, please write
7:17
Speaker 1: to me two questions at Daniel and Jorge dot com.
7:20
Speaker 1: I'd love to hear your answers. I know you're out there.
7:23
Speaker 1: You've been listening to the podcast for years and they've
7:25
Speaker 1: never written in. Today is the day you right in.
7:29
Speaker 1: So think about it for a minute before you listen
7:30
Speaker 1: to these answers. Do you think there's uranium on Uranus?
7:34
Speaker 1: Here's what people had to say. Earth has it, and
7:40
Speaker 1: all the other planets like Mercury, Mars, Asteroids and all
7:48
Speaker 1: that have uranium, Uranus being in our Solar system should
7:55
Speaker 1: have it too. I would say that, yes, there definitely
7:57
Speaker 1: has to be at least one atom of uranium on Uranus,
8:02
Speaker 1: seeing that uranium is distributed throughout the universe and um
8:06
Speaker 1: maybe concentrated more on rocky planets. But my guess is
8:10
Speaker 1: if we look really, really hard, we'd find that one atom. Yeah,
8:13
Speaker 1: why not? I guess that's it's a pretty big planet
8:17
Speaker 1: and it's mostly gas, but I don't think why there
8:22
Speaker 1: shouldn't be any other stuff than what it's made out of,
8:30
Speaker 1: because meteors and other things are constantly falling into it,
8:37
Speaker 1: and I guess they're bound to be some that consists
8:42
Speaker 1: of or have some uranium in them. So yeah, I'm
8:48
Speaker 1: pretty confident about that. I would guess yes, because you're
8:51
Speaker 1: asking it, but I'm not very confident in that answer.
8:54
Speaker 1: I'm gonna guess no. Uranus was named by people who
8:58
Speaker 1: did not know what uranium is, but they named it
9:01
Speaker 1: after a Greek god in Greek mythology. But what do
9:06
Speaker 1: I know? Yeah, I would think so because if I'm
9:10
Speaker 1: not mistaken, it's a high pressure environment, and I would
9:16
Speaker 1: guess that, you know, heavier elements and radioactive elements like
9:20
Speaker 1: uranium would develop in a higher pressure environment like Uranus,
9:24
Speaker 1: possibly closer towards the core. If there is any uranium
9:31
Speaker 1: on ur I don't think that there would be very
9:34
Speaker 1: much of it. There is probably a small amount scattered
9:38
Speaker 1: to me amongst the war particles from meteorites or just stardust,
9:47
Speaker 1: or maybe it has a rocky core, knows. I think
9:50
Speaker 1: it's mostly ice of light liquids, small molecules frozen, so
9:56
Speaker 1: it probably has a little. But you know, I think
9:59
Speaker 1: that two might be related in namesake only, I would
10:02
Speaker 1: say yes, definitely, at least one particle. I don't know.
10:08
Speaker 1: I don't think that's what the plan is named for,
10:10
Speaker 1: but I don't see a reason why it wouldn't have
10:13
Speaker 1: some uranium. Thanks so much for those answers. There were
10:16
Speaker 1: some really insightful answers in there. And actually, when Daniel
10:20
Speaker 1: proposed this question to me, initially, it made me realize
10:23
Speaker 1: that I didn't know how uranus got its name and
10:26
Speaker 1: I didn't know the answer to this question. And I
10:29
Speaker 1: agreed with some of the listeners. I thought, probably there's
10:32
Speaker 1: there's at least some uranium and uranus, because it seems
10:36
Speaker 1: like they would sort of have to be like maybe
10:37
Speaker 1: if it was in a comment or an asteroid that
10:39
Speaker 1: slammed into uranus, even if it wasn't made in there,
10:41
Speaker 1: it might show up there. But I actually didn't know
10:44
Speaker 1: the answer for sure, So I think I was in
10:46
Speaker 1: the same boat as a bunch of these listeners. But
10:49
Speaker 1: it turns out that I don't know too much about
10:51
Speaker 1: uranus and where it got its name. So can you
10:54
Speaker 1: tell us a bit about that, Daniel, Yeah, I love
10:56
Speaker 1: this question because it has two really fun science stories,
10:59
Speaker 1: the story of Uranus and the story of uranium, and
11:01
Speaker 1: then it ties them together. So Urin this is a
11:04
Speaker 1: really funny planet because it's history is hilarious, honestly, first
11:08
Speaker 1: of all, because it was seen many many times before
11:12
Speaker 1: anybody even understood that it was a planet. There's like
11:15
Speaker 1: so many missed opportunities to make like a cosmic scale discovery,
11:20
Speaker 1: leave your mark on humanity. Even back in like one
11:24
Speaker 1: b C. Hipparcos saw it, and there's like recordings of
11:27
Speaker 1: people seeing this thing in the sky going back to
11:30
Speaker 1: like sixteen ninety or seventeen fifty. People like saw it
11:34
Speaker 1: and noted it in their journals, but they didn't realize
11:38
Speaker 1: it was a planet for a long time. It still
11:40
Speaker 1: blows my mind that people in like the BC era,
11:43
Speaker 1: we're looking up at space and had enough of a
11:46
Speaker 1: knowledge about like what belonged where that they could notice
11:49
Speaker 1: that something new had moved in that like needed to
11:52
Speaker 1: be identified or something, Because you know, I still look
11:54
Speaker 1: up the night sky and I'm like, oh, that's a
11:55
Speaker 1: bunch of stuff up there. Even back then, they were
12:00
Speaker 1: doing a much better job than I do at cataloguing
12:02
Speaker 1: these things, and I find that very impressive. So what
12:04
Speaker 1: did they think that it was? Well, a lot of
12:06
Speaker 1: people just thought that it was a star. It's sort
12:08
Speaker 1: of dim and slowly moving because it's really far out
12:11
Speaker 1: there in the Solar System, and you know, the further
12:14
Speaker 1: out you are in the Solar System, the slower you orbit,
12:17
Speaker 1: like the actual linear speed is slower because the gravitational
12:20
Speaker 1: pull on the planet is less, so you move less rapidly.
12:23
Speaker 1: So in our sky urine, this doesn't move very fast.
12:27
Speaker 1: So some people just thought it was a star that
12:28
Speaker 1: like wandered a little bit because you know, it's sort
12:30
Speaker 1: of hard to keep track back in the day about
12:33
Speaker 1: what was moving in the sky and what was induced
12:36
Speaker 1: by the Earth rotation, etcetera, etcetera, And so for a
12:39
Speaker 1: long time people just thought it was a star. And
12:41
Speaker 1: then the guy who actually discovered it, a guy named Herschel,
12:43
Speaker 1: he saw it in the sky and he thought it
12:45
Speaker 1: was a comment at first, so he didn't even realize
12:48
Speaker 1: it was a planet. So the guy we give credit
12:50
Speaker 1: to for discovering it actually thought it was a comment
12:53
Speaker 1: when he saw it and recorded it. Don't comments tend
12:55
Speaker 1: to move faster than planets. I guess it's like more
12:58
Speaker 1: than two years ago. So calculating this stuff was tough.
13:01
Speaker 1: But why did you think it was a commet? Well
13:03
Speaker 1: because he did the calculation very carefully, because other people
13:06
Speaker 1: looked at his results and his data and they calculated
13:09
Speaker 1: the orbit from his data and they're like, no, that's
13:12
Speaker 1: not the orbit of a comet. That must be a planet.
13:14
Speaker 1: You know what's the difference. The difference is that the
13:16
Speaker 1: comet is like very eccentric orbit. A lot of these
13:19
Speaker 1: things come from like the Ort cloud, like really far
13:22
Speaker 1: out there in the Solar System, and then they exume
13:24
Speaker 1: in very close to the Sun before zooming out, whereas
13:27
Speaker 1: the planet is like a much larger object that's obviously
13:30
Speaker 1: cleared its field and orbits with a much more circular orbit.
13:34
Speaker 1: Not perfectly circular, but much more circular. And so it
13:37
Speaker 1: was other people who looked at Herschel's data and they
13:40
Speaker 1: decided it was a planet, and it was only Herschel
13:43
Speaker 1: later being like, oh, okay, yeah, I agree with you.
13:46
Speaker 1: What I saw was a planet. So like, I don't
13:48
Speaker 1: even know why he gets credit for this? There did
13:51
Speaker 1: he get to name it? And so then there was
13:53
Speaker 1: like a seventy year argument about how to name it.
13:56
Speaker 1: So Herschel wanted to name it George's Star, which is
14:00
Speaker 1: like a terrible name because it's not a star, so
14:02
Speaker 1: he thought he was a comment. He wanted to name
14:04
Speaker 1: it after a star, which makes those sense. Other people
14:07
Speaker 1: wanted to name it Neptune because we didn't have Neptune yet,
14:10
Speaker 1: or Neptune Great Britain, like even more awkward name if
14:14
Speaker 1: you can imagine. And finally somebody else suggested naming Uranus
14:18
Speaker 1: after the god of the sky, you know, to follow
14:21
Speaker 1: this pattern that were naming the planets after these Greek
14:24
Speaker 1: and Roman gods. And so there was a long, like
14:26
Speaker 1: seventy year battle about what to call this thing. One
14:29
Speaker 1: group of people calling it Uranus, another group of people
14:32
Speaker 1: calling it George's Star. And it wasn't until eighteen fifty
14:36
Speaker 1: when the British Navy the bureaucracy finally accepted the name
14:39
Speaker 1: Uranus that it like formally became Uranus. So it was
14:42
Speaker 1: like seventy years when people are arguing about like just
14:45
Speaker 1: what to call this thing, So like did they know
14:48
Speaker 1: what they were doing at the time, because anatomy was
14:50
Speaker 1: pretty far along at that point. Did they realize school
14:53
Speaker 1: children would be laughing for generations to come, or had
14:57
Speaker 1: had all the body parts not been quite named at
15:00
Speaker 1: at that point. That is a great question, and it
15:02
Speaker 1: might also have to do with like the evolution of
15:05
Speaker 1: the British accent. Right, I don't know what that word
15:07
Speaker 1: sounded like a hundred and fifty years ago, or what
15:10
Speaker 1: those two words that you have in mind sounded like,
15:13
Speaker 1: and if they sounded more or less similar, that's a
15:15
Speaker 1: great question. Linguists out there or historians of the British
15:18
Speaker 1: accent please write to us and let us know how
15:20
Speaker 1: similar those two words sounded over the years. We asked
15:23
Speaker 1: the big questions we do. We go all the way
15:27
Speaker 1: up there and ask all the big questions. But you know,
15:29
Speaker 1: it turns out to be scientifically, are really fascinating planet
15:33
Speaker 1: for lots of reasons. One reason is that it's a
15:35
Speaker 1: great example of a giant planet that's not a gas giant,
15:39
Speaker 1: right like Jupiter and Saturn. We call these planets gas
15:42
Speaker 1: giants because they're mostly hydrogen, but Neptune and Uranus we
15:46
Speaker 1: call them ice giants because they really are a different composition.
15:50
Speaker 1: And is that water ice or is that some other
15:52
Speaker 1: kind of ice? So there's a mixture of water, ice
15:55
Speaker 1: and ammonia and also methane, and the difference is really
15:59
Speaker 1: that sort of like a race to get the gas.
16:02
Speaker 1: Like in the formation of the Solar System, you start
16:04
Speaker 1: out with a huge blob of stuff which is mostly hydrogen,
16:08
Speaker 1: and then you know there's some rock and some water
16:10
Speaker 1: and some other stuff, but really by mass, it's almost
16:12
Speaker 1: all hydrogen, and almost all of it grabbed by the Sun.
16:16
Speaker 1: Right the whole Solar system is formed, because the Sun
16:18
Speaker 1: begins this gravitational collapse and because it becomes very quickly
16:22
Speaker 1: the densest thing, the heaviest thing, then it grabs all
16:25
Speaker 1: the gas. Like hydrogen, gas is very light and so
16:28
Speaker 1: gravity pulls on it very effectively. So then to have
16:30
Speaker 1: any gas, to accumulate any gas, you have to build
16:33
Speaker 1: up enough mass to steal some from the forming Sun,
16:36
Speaker 1: and so if you don't get big enough fast enough,
16:38
Speaker 1: then you don't really get very much gas. So Jupiter
16:42
Speaker 1: and Saturn like past this point where they can sort
16:44
Speaker 1: of have a runaway effect and grab some of the
16:47
Speaker 1: gas before the Sun got almost all of it. But
16:49
Speaker 1: Neptune and Uriness didn't get big enough fast enough, so
16:52
Speaker 1: they just ended up like a blob of ice and rock.
16:55
Speaker 1: So like the Moon and Mars didn't get most of
16:57
Speaker 1: those gas either, and then Earth got theres from getting
17:01
Speaker 1: collided with stuff. Yeah, and we have a whole fun
17:03
Speaker 1: episode about how the Earth got its atmosphere. It had
17:06
Speaker 1: a little bit of gas in the beginning, but then
17:08
Speaker 1: it was mostly stolen away by the Sun and blown off,
17:11
Speaker 1: and then it later recreated its atmosphere from volcanoes and
17:14
Speaker 1: commentary collisions. It's an incredible story. And that's one of
17:17
Speaker 1: the things I love about these questions is that it
17:19
Speaker 1: tells you the rich, rich history of the Solar System.
17:22
Speaker 1: It's not just like, oh, the planets formed and then
17:25
Speaker 1: they were zooming around for four and a half billion years.
17:27
Speaker 1: Like there are twists and turns and new characters and
17:31
Speaker 1: like lost characters, and probably planets that existed in the
17:34
Speaker 1: Solar System for millions or billions of years which are
17:36
Speaker 1: now lost because they've been thrown out when Jupiter went
17:39
Speaker 1: like in and then out again. It's a crazy story.
17:43
Speaker 1: It's like a soap opera, and it's amazing we've figured
17:45
Speaker 1: any of it out. So Urinest didn't managed to grab
17:49
Speaker 1: this stuff and then it didn't have the like help
17:51
Speaker 1: that Earth had to get it with all of that
17:54
Speaker 1: other stuff, and so that's how it ended up with
17:56
Speaker 1: not a lot of gas, that's right, And so we
17:58
Speaker 1: don't actually know that much about what's in Urinus. We
18:01
Speaker 1: have a model roughly for what it looks like, but
18:04
Speaker 1: it's important to realize that we haven't really studied it
18:07
Speaker 1: very much. We've looked at it with telescopes. We sent
18:09
Speaker 1: one probe by it voyage or two, but that's really
18:12
Speaker 1: the only close flyby of Uranus we've ever had. And
18:16
Speaker 1: so we have a model for what's going on inside it,
18:18
Speaker 1: which comes mostly from these models of solar system formation,
18:22
Speaker 1: like what do we think had time to get in there?
18:24
Speaker 1: And that model looks like a rocky core, so like
18:28
Speaker 1: basically a huge rock about like half of the mass
18:31
Speaker 1: of the Earth, and that's at the very center of it,
18:33
Speaker 1: and then it's surrounded most of the mass of urine.
18:36
Speaker 1: Is is this icy mantle and you know, we say ice,
18:39
Speaker 1: but it's mostly like a big water ammonia ocean. It's
18:43
Speaker 1: like liquid or it's or it's fluid. At least it's
18:46
Speaker 1: under a lot of pressure, so it can still move
18:48
Speaker 1: and flow. So do the way the Earth's mantle can,
18:51
Speaker 1: but you wouldn't say necessarily that it's liquid. So I
18:54
Speaker 1: think I'm getting confused yet. So so we you know,
18:55
Speaker 1: when we were talking about it not picking up a
18:57
Speaker 1: bunch of stuff, where did all this water in them
19:00
Speaker 1: when you come from? Was? Was that just stuff it
19:01
Speaker 1: got lucky to grab initially or did it come somewhere
19:04
Speaker 1: else from Earth? I feel like I already asked this question,
19:06
Speaker 1: but now I'm confused about where all this water came from. Right,
19:08
Speaker 1: So there's a huge amount of water and ice and
19:11
Speaker 1: ammonia in the Solar system. So the initial formation of
19:14
Speaker 1: the Solar system, you have this cloud of hydrogen. Most
19:17
Speaker 1: of the hydrogen went to the gas giants, but the
19:20
Speaker 1: other stuff is heavier, it's slower, and so it's sort
19:22
Speaker 1: of more likely to accumulate where it was initially. And
19:25
Speaker 1: this stuff is far enough out from the Sun that
19:27
Speaker 1: it stays frozen, so like the water is an ice
19:30
Speaker 1: form and the ammonia is frozen. And so all of
19:33
Speaker 1: this stuff that formed Urineus and Neptune and that was
19:36
Speaker 1: the stuff that was sort of in the outskirts of
19:37
Speaker 1: the Solar system originally, and then just sort of like coalesced. Like.
19:41
Speaker 1: Even further out in the Solar System is the Earth Cloud,
19:44
Speaker 1: which is a bunch more frozen objects that become comets,
19:47
Speaker 1: and those are also just balls of ice. So everything
19:50
Speaker 1: that's really really far out in the Solar System is
19:53
Speaker 1: basically just rock and ice at this point, and it
19:55
Speaker 1: pulls together to form these ice giant planets. I'm with
19:58
Speaker 1: you now. So the core of it is this big rock,
20:01
Speaker 1: and then outside of that, like thirteen masses of the Earth,
20:05
Speaker 1: is this hot, dense fluid. It's not frozen, right, It's
20:08
Speaker 1: called ice, but it's not frozen. It's it's very confusing,
20:11
Speaker 1: so it's sort of like an ocean. It's more like liquid,
20:14
Speaker 1: but it's not technically in that phase. So chemists out
20:17
Speaker 1: there would be particular about how this is referred to,
20:20
Speaker 1: but they do definitely call it an ice, and that's
20:23
Speaker 1: what most of Urinus is. And then outside of that,
20:26
Speaker 1: there's like an envelope. There's an atmosphere that's like another
20:29
Speaker 1: half the mass of the Earth, and that has some
20:31
Speaker 1: hydrogen and some other gases in it. That's sort of
20:33
Speaker 1: like the triple layers of Uranus. So I watch a
20:36
Speaker 1: bunch of kids shows with my kids, and I feel
20:39
Speaker 1: like the one fact about Urinus that we always hear
20:41
Speaker 1: is that it rotates on its side. Do we know
20:44
Speaker 1: why it's rotated? Why all those layers are rotating the
20:48
Speaker 1: wrong way? Did it get hit by something and sort
20:50
Speaker 1: of knocked off kilter. It's super cool that it's doing that, because,
20:54
Speaker 1: as you say, it's evidence that something happened, And the
20:57
Speaker 1: reason it has to be evidence that something happened is
21:00
Speaker 1: that we're pretty sure a planet can't just naturally form
21:03
Speaker 1: that way. You notice that, like all the planets are
21:06
Speaker 1: sort of in the same plane. That's the plane we
21:08
Speaker 1: call the ecliptic, and it's also very well aligned with
21:11
Speaker 1: how the Sun rotates, So the Sun is spinning as well. Right,
21:15
Speaker 1: it's not just sitting there in the center of the
21:16
Speaker 1: Solar System. It spins and the planets spin around it,
21:19
Speaker 1: and each of the planets then spin around their axes,
21:22
Speaker 1: and almost all of this spin is in the same direction,
21:26
Speaker 1: Like if you drew a line between the north and
21:27
Speaker 1: the south pole of the Sun, that would give you
21:30
Speaker 1: an axis, and most of the Solar System is on
21:33
Speaker 1: a plane perpendicular to that, and most of the planets
21:36
Speaker 1: rotate around their own axis that's parallel to the Sun's axis.
21:39
Speaker 1: So for most of the Solar System it's very well organized.
21:42
Speaker 1: And that's not like a coincidence. It's not like it
21:44
Speaker 1: just happened to end up that way, like we could
21:46
Speaker 1: have had planets in any random direction. It comes from
21:49
Speaker 1: angular momentum conservation. Like when something is spinning, it has
21:52
Speaker 1: to keep spinning. There's no way like for it to
21:54
Speaker 1: stop spinning unless you come in with something from the outside,
21:57
Speaker 1: like if you start a top spinning in space is
22:00
Speaker 1: just going to keep going forever. And that's what happened
22:02
Speaker 1: with the Solar system, is that it collapses gravitationally but
22:06
Speaker 1: has to keep spinning, and so it has to keep
22:08
Speaker 1: spinning around that original axis. It can collapse sort of
22:11
Speaker 1: parallel to that axis, which is why you get a
22:13
Speaker 1: flat disc, but the disc itself can't collapse much further
22:17
Speaker 1: because it has to keep spinning. So everything spinning sort
22:20
Speaker 1: along the same axis. So to get urinous knocked over
22:24
Speaker 1: on its side requires, as you said, like some huge
22:27
Speaker 1: rock like a lost moon or another planet somehow that
22:31
Speaker 1: banged into it and knocked it over. So it's really
22:34
Speaker 1: is evidence of like an incredible cosmic collision. I feel
22:37
Speaker 1: like I'm just going to go ahead and blame Jupiter
22:38
Speaker 1: because it seems like the answer for so many things is, well,
22:42
Speaker 1: Jupiter did something weird and that might not be consistent,
22:45
Speaker 1: but I'm going to go ahead and blame Jupiter anyway,
22:47
Speaker 1: because is that your parenting strategy? You like, you pick
22:50
Speaker 1: one kid who's always to blame. You're like, look, I
22:52
Speaker 1: didn't see it, but it's usually you. But I pretty
22:55
Speaker 1: much know the Actually it's the dog that I usually
22:57
Speaker 1: There you go. The dog is the source of chaos. Yes,
23:01
Speaker 1: you know. I think that's an underappreciated role of dogs
23:04
Speaker 1: in human history. You know, it's just taken the blame
23:06
Speaker 1: for other people's misdeeds or farts around the campfire or
23:10
Speaker 1: all sorts of stuff. She is the scapegoat, but she's
23:14
Speaker 1: a good sport about it, all right. Well, so now
23:17
Speaker 1: we're all on board about what urineus is like, so
23:21
Speaker 1: I think it's time that we take a little break
23:23
Speaker 1: and then we'll get to uranium. Okay, so now we've
23:39
Speaker 1: talked about what we know about uranus, and uranus and
23:43
Speaker 1: uranium sound really similar. So let's learn about uranium and
23:48
Speaker 1: see if there's any connection. There, So there actually is
23:50
Speaker 1: some connection in the name. I mentioned earlier that when
23:54
Speaker 1: they discovered the planet there was a bit of an
23:56
Speaker 1: argument about what to name it, And so Uranium was
23:59
Speaker 1: discovered about eight years after Uranus, and the guy who
24:03
Speaker 1: named uranium uranium did so sort of to vote for
24:08
Speaker 1: Uranus as the name of the planet. He was like,
24:10
Speaker 1: naming uranium after this newly discovered planet. He wanted to
24:14
Speaker 1: influence the astronomy community towards the name Uranus. WHOA, So
24:19
Speaker 1: did he have any influence? Like he did it? But
24:21
Speaker 1: did it matter? Do we know? I don't know. We
24:22
Speaker 1: have to run the counter experiment or we see what
24:25
Speaker 1: would have happened if he hadn't done that. I'm not sure,
24:27
Speaker 1: but I think it was always going to be Uranus.
24:30
Speaker 1: It was just, you know, it's going to be a
24:31
Speaker 1: matter of time before the British bureaucracy gave it up.
24:34
Speaker 1: What a kind of crumby reason for naming an element, though, like,
24:37
Speaker 1: unless there's some astronomy connection there to just be like no, no,
24:41
Speaker 1: I really want you to do this naming thing. But anyway,
24:43
Speaker 1: I guess you know, we're all humans. Our logic is
24:46
Speaker 1: sometimes convoluted. Yeah, And you know, you discover something, you
24:49
Speaker 1: get to name it. You don't always have a good reason.
24:51
Speaker 1: As we talked about a lot on this podcast, some
24:53
Speaker 1: of these names are pretty whimsical and pretty ridiculous. I mean,
24:56
Speaker 1: there's like Berkeley m and California UM and Americum, and
24:59
Speaker 1: the names the elements are pretty silly, fair enough, some
25:02
Speaker 1: of them are fun to say, like you SI, But
25:04
Speaker 1: as we talked about earlier, the planets each have a
25:06
Speaker 1: really cool story. Each of the elements also has a
25:09
Speaker 1: really really cool story that goes back much much further
25:13
Speaker 1: than the story of our particular solar system. So tell
25:16
Speaker 1: us about how this one was found. So the important
25:18
Speaker 1: thing to understand about uranium is that it's not made primordially,
25:23
Speaker 1: like the very beginning of the universe, when things are
25:25
Speaker 1: super hot and dance in these particles whizzing around everywhere,
25:28
Speaker 1: and then things are cooling down. Just after the Big Bang,
25:31
Speaker 1: we get atoms formed, but mostly we just made hydrogen
25:35
Speaker 1: and a very small amount of helium. So the very
25:38
Speaker 1: early universe is basically just like a huge hydrogen cloud,
25:42
Speaker 1: definitely no uranium. So uranium does not date back to
25:46
Speaker 1: the beginning of the Big Bang like the electrons in
25:49
Speaker 1: your body, and the protons in your body are probably
25:51
Speaker 1: older than every uranium nucleus out there, so uranium came later, Right,
25:56
Speaker 1: It took a while to make uranium in our universe.
25:59
Speaker 1: It's really cool, and we're gonna do a whole podcast
26:01
Speaker 1: episode focused just on like what is out there in
26:04
Speaker 1: the universe and how is made in the relative population
26:06
Speaker 1: of all these materials, because they all tell such cool stories,
26:09
Speaker 1: and it took a while for people to figure out, like, well,
26:11
Speaker 1: where did all the rest of this stuff come from? Like,
26:14
Speaker 1: once they realized that you couldn't make anything heavier than
26:18
Speaker 1: helium or a little bit of lithium in the Big Bang,
26:20
Speaker 1: they had to look around to find a place in
26:23
Speaker 1: the universe to make these heavier elements, and it took
26:26
Speaker 1: people a while, but they figured out that some of
26:27
Speaker 1: the elements could be made, of course, inside stars, and
26:31
Speaker 1: it's the intense heat and pressure that allows you to
26:34
Speaker 1: make these things. Yes, stars operate by fusion, right, so
26:37
Speaker 1: they are glowing and super hot, and they're this exciting
26:39
Speaker 1: balance between gravity which is compressing all of this stuff.
26:43
Speaker 1: It's like a runaway effect where you got this huge
26:45
Speaker 1: compression of all this hydrogen gas, and then fusion. If
26:49
Speaker 1: you get all these protons close enough together, you squeeze
26:52
Speaker 1: them together, you overcome the fact that they like to
26:55
Speaker 1: repel each other because they're both too positive charges, and
26:58
Speaker 1: eventually they form heavier off So two hydrogen atoms confused
27:02
Speaker 1: together to form helium and helium confused together to form
27:05
Speaker 1: heavier stuff. And if you have a big enough star,
27:08
Speaker 1: then the products of one fusion cycle, like the helium
27:10
Speaker 1: from fusing hydrogen, can become the fuel for the next one,
27:14
Speaker 1: and then the fuel for the next one, and really
27:16
Speaker 1: big stars they develop these incredible layers we have like
27:19
Speaker 1: hydrogen on the outside, and then a layer of helium,
27:22
Speaker 1: and then a layer of something heavier and a layer
27:24
Speaker 1: of something heavy go calcium and oxygen, and all the
27:26
Speaker 1: way up, and the biggest stars they confuse stuff all
27:30
Speaker 1: the way up to iron. So iron is element fifty six,
27:34
Speaker 1: and it means that at the core something is fusing
27:37
Speaker 1: two elements together and producing iron. And that's where a
27:40
Speaker 1: lot of these elements that are too heavy to have
27:42
Speaker 1: been made in the Big Bang are made. But stars
27:45
Speaker 1: can only fuse up to iron, like before iron. Anything
27:49
Speaker 1: lighter than iron. If you fuse it, you get a
27:51
Speaker 1: byproduct and you get energy out, and that's how the
27:53
Speaker 1: star glows. But iron, if you try to fuse iron together,
27:57
Speaker 1: it actually costs you energy. So if you fuse iron together,
28:01
Speaker 1: you'll cool down the star. You will kill the star
28:04
Speaker 1: if you try to fuse iron together. But we have
28:06
Speaker 1: stuff higher than iron, and so is stuff higher than
28:10
Speaker 1: iron made in dying stars. So for a long time
28:13
Speaker 1: people really didn't understand this. They're like, well, stars can't
28:16
Speaker 1: make higher than iron. But as you say, obviously we
28:18
Speaker 1: have like gold and platinum and plutonium and uranium. Where
28:21
Speaker 1: do all these things come from? And so people thought
28:24
Speaker 1: for a while, as you said, that maybe they come
28:25
Speaker 1: from supernova, that maybe the special conditions when a star
28:29
Speaker 1: explodes might be enough to trigger, you know, this kind
28:33
Speaker 1: of heavier element fusion. But the story didn't really hang together,
28:37
Speaker 1: like it's potentially possible for this to happen, but they
28:40
Speaker 1: didn't really see evidence for it around supernova. And the
28:43
Speaker 1: problem is that this process is very delicate. Like above iron,
28:46
Speaker 1: in order to make something heavier, you need to absorb
28:48
Speaker 1: like multiple neutrons at the same time. Like if you
28:52
Speaker 1: absorb one neutron, you become very unstable and just break up.
28:55
Speaker 1: If you absorb two neutrons, then boom, you can transmute
28:58
Speaker 1: into this heavier thing. So you have to like absorb
29:01
Speaker 1: to neutrons almost simultaneously. It's called this our process for
29:05
Speaker 1: rapid process. And to do that you need like a
29:07
Speaker 1: lot of neutrons around you so that you have like
29:09
Speaker 1: enough that sometimes you'll get two of them coming in
29:12
Speaker 1: at the same time. And that's very difficult to do
29:14
Speaker 1: in the environment of a supernova because supernova is expanding,
29:17
Speaker 1: it's exploding. And the other problem with supernovas is that
29:20
Speaker 1: while they might make some of this stuff, they don't
29:22
Speaker 1: really like ejected out there into the Solar system. We
29:26
Speaker 1: don't just want to make uranium. We need to make
29:28
Speaker 1: uranium and then have it be the seeds for a
29:30
Speaker 1: future solar system. If it's just made inside a star
29:33
Speaker 1: and then like kept inside the remnant of that star,
29:35
Speaker 1: it's not going to end up here on Earth or
29:38
Speaker 1: as part of our Solar system. So recently people found
29:41
Speaker 1: another way to make these super duper heavy elements that
29:45
Speaker 1: wasn't just supernova's suspense is killing me? What is it?
29:48
Speaker 1: So the answer to how to get a bunch of
29:50
Speaker 1: neutrons together, like a really high density of neutrons, so
29:53
Speaker 1: you can do this kind of thing is neutron stars.
29:56
Speaker 1: Neutron stars are these remnants of old dead stars, right,
29:59
Speaker 1: they've already blown up up and collapse, and they have
30:01
Speaker 1: this leftover core that's super incredibly dense. Now, when two
30:05
Speaker 1: of these things collide, like two neutron stars in a
30:08
Speaker 1: binary system for example, spiral into each other and collide,
30:11
Speaker 1: then you get this incredible cataclysmic event of really unparalleled density,
30:16
Speaker 1: not enough to become a black hole, but to form
30:19
Speaker 1: maybe a larger neutron star or to blow some of
30:21
Speaker 1: this stuff out. And so recently, because of gravitational wave observatories,
30:25
Speaker 1: we've been able to see these neutron star collisions happen,
30:29
Speaker 1: and they're really cool things that you can see the
30:31
Speaker 1: gravitational waves that they make like actual shaking of space
30:35
Speaker 1: because they're so dense, and you can also look at
30:37
Speaker 1: them with telescopes and you can see the light that
30:39
Speaker 1: comes from them, so like you can see it in
30:41
Speaker 1: two totally different ways, the gravitational waves and in the optical.
30:46
Speaker 1: And when they look in the optical they see light
30:48
Speaker 1: coming from these and they can see light from like
30:51
Speaker 1: excited gold or excited uranium is like gases of golden
30:55
Speaker 1: uranium get thrown out into the universe and because they're hot,
30:59
Speaker 1: they emit light and it has a particular fingerprint and
31:02
Speaker 1: we can see it here on Earth. So we have
31:04
Speaker 1: seen the birth of these super heavy elements in neutron
31:07
Speaker 1: star collisions. So that's totally wild. So that seems like
31:11
Speaker 1: two super rare conditions that need to come together, and
31:15
Speaker 1: that has produced everything above iron. So many of those
31:19
Speaker 1: things are things that we depend on. And so like,
31:22
Speaker 1: did any of that happen in our solar system? How
31:24
Speaker 1: did how did it get here? Absolutely none of that
31:27
Speaker 1: could happen in our solar system. There's nowhere in our
31:30
Speaker 1: solar system that is capable of making these things. Like
31:32
Speaker 1: even at the heart of our star, all they can
31:35
Speaker 1: do is burn helium or hydrogen. Right, our star is
31:38
Speaker 1: not going to be big enough to even make iron.
31:40
Speaker 1: And so that means that every heavy metal that you
31:43
Speaker 1: see if you're wearing a gold wedding ring right now,
31:45
Speaker 1: that gold was made probably in a neutron star collision
31:49
Speaker 1: before our solar system was even formed. Right, So all
31:53
Speaker 1: of the uranium, all the gold, all the heavy elements
31:55
Speaker 1: in our solar system predate our solar system completely, and
31:59
Speaker 1: our solar system comes from gathering together the remnants of
32:02
Speaker 1: a previous solar system. Some stars died and became neutron
32:06
Speaker 1: stars and then collided together and made these heavy elements
32:09
Speaker 1: and spewed them out into some gas cloud which then
32:13
Speaker 1: coalesced into our solar system, still mostly hydrogen, but with
32:17
Speaker 1: a few nuggets of these heavier interesting things to like
32:20
Speaker 1: spice it up a little bit. Science is so beautiful,
32:22
Speaker 1: you know. You you walk around and now you know
32:24
Speaker 1: the stuff and you see the whole world differently. Like anyway,
32:27
Speaker 1: the next time I'm walking through a jewelry store, maybe
32:29
Speaker 1: I'll appreciate it. It It is really incredible, especially these heavy
32:33
Speaker 1: with things like gold and platinum and plutonium and uranium.
32:36
Speaker 1: They're so difficult to make, and so that tells you
32:39
Speaker 1: that something crazy must have happened really far away, a
32:42
Speaker 1: really long time ago. And so yeah, these elements on
32:45
Speaker 1: your fingers are much older than the Earth itself, right,
32:49
Speaker 1: Like that gold has been hanging out before the Earth
32:52
Speaker 1: was even formed, and it's it's super amazing. Yeah, so
32:54
Speaker 1: this stuff got made and not in our solar system
32:58
Speaker 1: but it ended up in our solar system, and so
33:01
Speaker 1: because it was made before our solar system, is it
33:03
Speaker 1: sort of evenly distributed between the stuff that we have
33:08
Speaker 1: in our solar system or did it sort of get
33:09
Speaker 1: clumpy and sucked into certain bodies and not others. That
33:12
Speaker 1: is a great question, and that is really the heart
33:15
Speaker 1: of the question. We haven't been able to study that
33:17
Speaker 1: in great detail because the only example we really can
33:20
Speaker 1: study is the Earth and then the few things that
33:23
Speaker 1: fall to the Earth from space. You know, like you
33:26
Speaker 1: could ask the question, do asteroids have the same composition
33:29
Speaker 1: of stuff as the Earth? And do things further out
33:32
Speaker 1: have the same composition of stuff? So the short answers
33:35
Speaker 1: we don't know exactly. We know that there are variations
33:38
Speaker 1: because of where you are in the Solar system, like
33:40
Speaker 1: the further out you are there tend to be different
33:42
Speaker 1: things than closer in. But one clue is that uranium
33:47
Speaker 1: is very very abundant. It's very very widespread. It's like
33:51
Speaker 1: actually the fifty one most common element on the Earth,
33:55
Speaker 1: which you know, it doesn't sound it's not in the
33:56
Speaker 1: top ten or anything, but for us, such a big
33:59
Speaker 1: heavy element, and there's you know, more than a hundred elements.
34:02
Speaker 1: It's pretty far up there. And is it about that
34:05
Speaker 1: common in asteroids and comments and stuff as well, or
34:08
Speaker 1: we really only know that ranking forth. We know that
34:11
Speaker 1: ranking well for Earth and a lot of the asteroids
34:13
Speaker 1: are different. But when we study asteroids, we also do
34:16
Speaker 1: see these things in asteroids. And you know, something else
34:19
Speaker 1: that's I think not widely understood is that uranium is everywhere.
34:22
Speaker 1: It's basically in all of the sands, in every rock.
34:26
Speaker 1: The biggest supply of uranium we have on Earth is
34:28
Speaker 1: actually in the Earth's oceans. There's an incredible amount of
34:32
Speaker 1: uranium just dissolved into the oceans. And these days people
34:35
Speaker 1: are thinking about trying to get uranium out of the
34:37
Speaker 1: water because it might be cheaper than digging it out
34:40
Speaker 1: of the ground. So uranium is everywhere all over the planet,
34:45
Speaker 1: but it must be in very low levels because none
34:48
Speaker 1: of us are worried about getting cancer from swimming in
34:50
Speaker 1: the ocean, Is that right? That's right. Uranium is sort
34:54
Speaker 1: of just part of this radioactive background that exists from
34:57
Speaker 1: living on Earth. You know, the Earth is slightly radio active. Also,
35:00
Speaker 1: we get radiation from the sky, you know, from cosmic rays,
35:04
Speaker 1: and so yeah, there is some effect on our DNA
35:07
Speaker 1: from naturally present uranium in the soil, just like there's
35:12
Speaker 1: effect on our DNA from muns coming from the sky
35:15
Speaker 1: that occasionally like change something or you know, create an error.
35:19
Speaker 1: And that's I think an important part of evolution. I
35:21
Speaker 1: think evolution. It would have happened differently if we had
35:24
Speaker 1: no radioactive elements on Earth. It would have lowered the
35:27
Speaker 1: number of mutations that occur. Right, it's not something necessarily
35:30
Speaker 1: to be worried about. So you shouldn't, you know, isolate
35:32
Speaker 1: uranium and eat a lot of it or anything. But
35:35
Speaker 1: it is definitely present all around us. Interesting, and how
35:38
Speaker 1: how long have we known about uranium? So uranium was
35:40
Speaker 1: also discovered or just after uranus, right, and so only
35:45
Speaker 1: like more than a hundred years. And it was discovered
35:48
Speaker 1: sort of accidentally by a chemist who was just playing
35:51
Speaker 1: around with something called pitch blend and dissolving it with stuff,
35:54
Speaker 1: and he came up with something that felt to him
35:56
Speaker 1: like a new undiscovered element. And it was like hundred
36:00
Speaker 1: years later the people realized that it was radioactive. So
36:04
Speaker 1: they had been like studying it without knowing they should
36:07
Speaker 1: be careful. I guess we didn't understand radio activity until
36:11
Speaker 1: much later. Exactly this was the discovery of radioactivity. So
36:15
Speaker 1: uranium is a really important role in science itself. It's
36:18
Speaker 1: the late eighteen hundreds when Beckerel sort of left a
36:21
Speaker 1: bunch of uranium on a photography plate in a drawer
36:24
Speaker 1: and he came back to found that it had like
36:26
Speaker 1: imprinted itself on the plate. It was like in a
36:29
Speaker 1: darkened drawer, no light in there, but somehow these blobs
36:32
Speaker 1: of uranium left an imprint of fog on this plate,
36:36
Speaker 1: and so he realized, hold on a second, there's something
36:38
Speaker 1: going on here. And that was the discovery of radiation
36:41
Speaker 1: that some materials like shoot out these particles that can
36:45
Speaker 1: fog a plate, and you know, that stimulated the curies
36:48
Speaker 1: and they discovered radium, and that, you know, really triggered
36:51
Speaker 1: much of nuclear physics and modern physics. So it was
36:54
Speaker 1: a real turning point sort in science, this discovery of
36:57
Speaker 1: uranium as a radioactive element. I love these exam couples
37:00
Speaker 1: of dumb luck, you know, like whoops, I put my
37:02
Speaker 1: uranium down on a photography plate. And now the whole
37:06
Speaker 1: direction of sciences is shifting rapidly to understand what radioactivity means.
37:11
Speaker 1: And it's pretty cool. Would you rather make a like
37:13
Speaker 1: historic discovery through dumb luck so you have a nice anecdote,
37:17
Speaker 1: or through like the sheer force of your brilliance. I mean,
37:20
Speaker 1: I think I'd probably feel my ego would feel better
37:23
Speaker 1: if I did it through the sheer force of my brilliance.
37:26
Speaker 1: But I'll take it anyway it comes. So randomness is
37:29
Speaker 1: good too. Yeah. I love these stories of people like
37:31
Speaker 1: looking for one thing and then accidentally discovering something else
37:35
Speaker 1: because it reminds me to keep in my mind open
37:37
Speaker 1: and to keep my eyes wide because you never know
37:40
Speaker 1: in what experiment is going to be the hints of
37:42
Speaker 1: something like a crazy discovery. And usually once you've made
37:45
Speaker 1: a discovery, people can go back through history and find
37:48
Speaker 1: evidence for it beforehand, just like now we know ur
37:51
Speaker 1: in this is a planet. We can see in data
37:53
Speaker 1: collected hundreds of years earlier and people's log notebooks like, oh,
37:56
Speaker 1: you could have discovered this, you have the data right here.
37:58
Speaker 1: People have missed opportunities to make incredible discoveries because they
38:02
Speaker 1: weren't looking for them or they didn't think about that,
38:05
Speaker 1: And so it's a message there's like keep your mind
38:07
Speaker 1: open because you never know you know what the universe
38:10
Speaker 1: is telling you right now. You never know when you're
38:12
Speaker 1: fumbling towards a discovery. And the uranium we have here
38:17
Speaker 1: on Earth is a really interesting story because it comes
38:19
Speaker 1: in two different flavors. It's two isotopes of uranium. Most
38:22
Speaker 1: of the uranium we have here on Earth is two
38:24
Speaker 1: thirty eight, which is pretty stable as a half life
38:27
Speaker 1: of like four and a half billion years, but it's
38:29
Speaker 1: not as useful for things like fission if you want
38:32
Speaker 1: to make weapons or reactors. The other kind is called
38:35
Speaker 1: uranium two thirty five, and it's much better for making
38:39
Speaker 1: things like reactors, but it's pretty rare. So like most
38:42
Speaker 1: of the stuff when you mind, it is uranium two
38:44
Speaker 1: thirty eight. And then if you want to do reactors
38:47
Speaker 1: or build weapons, you have to isolate and enhance the
38:50
Speaker 1: fraction of uranium two thirty five. So that's why you
38:53
Speaker 1: hear about like centrifuges because they separate the different isotopes
38:57
Speaker 1: by weight so you can get more of the two
38:59
Speaker 1: thirty five that you need. Yeah, this is such a
39:01
Speaker 1: weird element for humanity. Like in the one hand, I'm
39:04
Speaker 1: a huge fan of nuclear power plants because they put
39:08
Speaker 1: out less carbon, and on the other hand, I just
39:10
Speaker 1: don't know if humanity can handle it, because you can
39:12
Speaker 1: also turn it into weapons, and it doesn't take too
39:15
Speaker 1: many idiots to make trouble. And anyway, these things are complicated.
39:19
Speaker 1: Thanks humanity, it is complicated. And it's also interesting that
39:23
Speaker 1: the uranium two thirty five, the stuff that's useful for this,
39:26
Speaker 1: is sort of going away because it's half life is
39:29
Speaker 1: much shorter. It's only seven hundred million years, which sounds
39:32
Speaker 1: like a long time, but what it means is that,
39:34
Speaker 1: like the useful fraction of uranium over the history of
39:37
Speaker 1: the Earth is dropping sort of steadily, like we have
39:40
Speaker 1: a lot less of two thirty five than we did
39:43
Speaker 1: a long time ago, and if you wait like another
39:45
Speaker 1: few hundred million years, it's going to be even less.
39:47
Speaker 1: We did a whole podcast episode once about a naturally
39:50
Speaker 1: occurring fission reactor because like a billion or two years ago,
39:54
Speaker 1: there was a uranium deposit in Africa that was rich
39:58
Speaker 1: enough in you two thirty five that it was b
40:00
Speaker 1: ethically a nuclear reactor naturally created that burned for hundreds
40:04
Speaker 1: of thousands of years, and I'm like, heat it up
40:06
Speaker 1: this rock underground, but that can't happen anymore, because uranium
40:10
Speaker 1: doesn't occur in enough density anymore for that kind of
40:13
Speaker 1: stuff to happen. So we have to like dig it
40:15
Speaker 1: out of the ground and use centrifuges to enhance the
40:18
Speaker 1: fraction of our uranium that has two thirty five. So
40:21
Speaker 1: note humanity the clock is taking up figuring out fusion.
40:26
Speaker 1: On that note, let's take a break and we'll come
40:28
Speaker 1: back and hear a little bit more about uranium. Okay,
40:43
Speaker 1: so we've talked a little bit about the way humanity
40:47
Speaker 1: is helped are hurt by uranium two thirty five. Let's
40:51
Speaker 1: hear a little bit more about some of the other
40:53
Speaker 1: properties about uranium. So you told us that it has
40:58
Speaker 1: a high atomic weight because it's high or than iron.
41:00
Speaker 1: So you need these very particular situations so that you
41:03
Speaker 1: can get it. If you had like a chunk of
41:06
Speaker 1: uranium sitting on your table, you'd probably be scared. But
41:10
Speaker 1: what would it look like? Yeah, that's a cool question. Well,
41:12
Speaker 1: it's actually malleable. It's like not that hard. It's it's
41:16
Speaker 1: denser than lead, but it's it's soft and it's silvery white,
41:20
Speaker 1: so it's actually kind of pretty, you know, I mean,
41:23
Speaker 1: I wouldn't recommend doing any art with it, but it's
41:25
Speaker 1: kind of a cool looking thing. And it's cool that
41:27
Speaker 1: every element has its own like sort of feel to it, right,
41:30
Speaker 1: It's own like texture and color and look, and that
41:33
Speaker 1: all of these properties, the difference between uranium and the
41:36
Speaker 1: other things, just come out of the structure of the atom. Right,
41:39
Speaker 1: We're talking about how the electrons fill their orbitals and
41:42
Speaker 1: all of this stuff. It's incredibly rich and interesting that
41:46
Speaker 1: all of these elements have such different properties. I love
41:49
Speaker 1: that about the universe that like a few very simple
41:52
Speaker 1: things coming together in lots of different ways can make
41:55
Speaker 1: so many interesting different kinds of materials. That is totally epic.
41:59
Speaker 1: And I think it's interest thing that you mentioned art
42:01
Speaker 1: because when we moved to our permanent house, what what
42:04
Speaker 1: we hope is our permanent house. I wanted to go
42:06
Speaker 1: out and gets to wear dishwear because I think they
42:10
Speaker 1: look really nice. And I was warned by someone that
42:13
Speaker 1: I shouldn't get the red ones because the red ones
42:16
Speaker 1: are radioactive because of uranium. Can you tell us more
42:19
Speaker 1: about that uranium mix as well with lots of other
42:22
Speaker 1: things and forms all sorts of interesting uranium oxides and
42:25
Speaker 1: some of these have a really spectacular color. Um. You know,
42:28
Speaker 1: some of them are yellow, some of them are very red.
42:31
Speaker 1: And you know, if you're trying to create colors like
42:33
Speaker 1: these days, it's easy to do digitally, right, you just
42:35
Speaker 1: dial in whatever pixel you want. But if you're out
42:37
Speaker 1: there working with your hands and you want to create dyes,
42:40
Speaker 1: you need to find natural sources of color. And so
42:42
Speaker 1: uranium made this really sort of bright, vivid red that
42:46
Speaker 1: was hard to duplicate in other ways. And so before
42:49
Speaker 1: we understood like really the dangers of radiation and radioactivity,
42:53
Speaker 1: uranium was used all sorts of places to make these
42:56
Speaker 1: kind of things, and in your dinner wear, so you're
42:58
Speaker 1: like sitting at the dinner table and you're play it
43:00
Speaker 1: is like shooting particles into your body. I guess that's
43:03
Speaker 1: okay because there hasn't been a strong correlation between Fiesta
43:07
Speaker 1: wear and cancer, I guess, or or was that bad?
43:10
Speaker 1: I don't think it's okay. I don't think they're making
43:12
Speaker 1: it anymore, you know, for the same reasons that like
43:14
Speaker 1: they're no longer using glowing wrist watch faces. You know
43:17
Speaker 1: that like glow with radiation. I think it's sort of
43:20
Speaker 1: like lead in the sense that more radiation is definitely
43:23
Speaker 1: more bad for you, and you want to limit your exposure.
43:26
Speaker 1: You know, we used to like take X rays all
43:28
Speaker 1: the time, and the X rays would like be super powerful,
43:31
Speaker 1: much stronger than we needed in order to see clearly,
43:33
Speaker 1: because we didn't understand the danger of X rays. So
43:35
Speaker 1: now I think we work really hard to limit our
43:37
Speaker 1: exposure to radiation. Yeah, but that sounds like a good plan.
43:40
Speaker 1: And I didn't end up getting the Fiesta wear because
43:42
Speaker 1: I didn't feel like I could get a good handle
43:44
Speaker 1: on how dangerous it was. But uranium also tells us
43:47
Speaker 1: a lot about the history of the Earth as well.
43:49
Speaker 1: This is really fun story about a geologist trying to
43:52
Speaker 1: understand the age of the Earth and trying to solve
43:54
Speaker 1: the puzzle by actually looking for an asteroid that crashed
43:58
Speaker 1: onto the Earth. He wants to know if rocks on
44:01
Speaker 1: that he found in the Earth were actually the oldest
44:03
Speaker 1: things that one could find. He was looking to see
44:06
Speaker 1: if things in the Solar System might be even older
44:09
Speaker 1: than the rocks we find on the Earth, because you know,
44:11
Speaker 1: if you're trying to date the Earth and you're just
44:12
Speaker 1: like looking around for rocks, you wonder, like, well, it's
44:15
Speaker 1: his rock, as old as the Earth itself. So he
44:18
Speaker 1: actually went out to Meteor Crater, this huge crater in
44:21
Speaker 1: Arizona that you should totally visit if you're ever in Arizona.
44:25
Speaker 1: It's incredible. It's just like a flat expanse and then
44:28
Speaker 1: this incredible scoop, just like dug out of the Earth
44:32
Speaker 1: by this meteor that hit a long long time ago.
44:34
Speaker 1: He went down into the center of it and they
44:36
Speaker 1: have like a chunk of the original meteor and they
44:39
Speaker 1: let him sample it. And he looked at that rock
44:41
Speaker 1: and he used uranium actually to date the age of
44:45
Speaker 1: that asteroid. So did he get lucky because that asteroid
44:48
Speaker 1: has uranium. Well, uranium is almost everywhere, right, It's in
44:51
Speaker 1: almost every single rock in the Solar System, it turns out.
44:54
Speaker 1: But a really interesting thing about uranium is that when
44:57
Speaker 1: rocks form, they formed these little crystals called zircons, and
45:01
Speaker 1: these crystals, for complicated reasons, they like to slurp in uranium,
45:05
Speaker 1: but they reject lead. So like no lead ever forms
45:08
Speaker 1: in the center of these zircon crystals. But uranium turns
45:11
Speaker 1: into lead at a very regular rate because it decays radioactively.
45:15
Speaker 1: So if you have there Basically it's like a clock.
45:17
Speaker 1: You have these crystals that start out with uranium and
45:19
Speaker 1: then they gradually get lead in them, and you know
45:22
Speaker 1: that they had no lead when they were formed because
45:24
Speaker 1: the crystals like reject the lead. So if you look
45:26
Speaker 1: at one of these crystals, you can tell how long
45:29
Speaker 1: it's been around just by counting the uranium and counting
45:32
Speaker 1: the lead, and you can figure out like, oh, this
45:34
Speaker 1: crystal has been ticking for seven hundred million years or
45:37
Speaker 1: for four point two billion years. It's an incredible way
45:40
Speaker 1: to date the age of a rock. That is incredible
45:43
Speaker 1: and super useful. Thank you physics. Yeah, so this guy
45:47
Speaker 1: dug out that crater and he discovered he's the first
45:49
Speaker 1: person to really nailed down the age of the Solar
45:52
Speaker 1: System to be about four and a half billion years old.
45:56
Speaker 1: It's really important discovery, again connected to uranium, and it
46:00
Speaker 1: interesting side note is that when he was doing that study,
46:02
Speaker 1: he was trying to measure the amount of lead in
46:04
Speaker 1: these crystals, and he discovered that his entire lab was
46:07
Speaker 1: basically covered in lead. There was lead everywhere. There's lead
46:10
Speaker 1: on the walls, it was lead in the air, there
46:11
Speaker 1: was lead everywhere. Because of lead in gasoline, and he
46:14
Speaker 1: actually led the charge to help remove lead from gasoline
46:17
Speaker 1: because he's the one who discovered that we were poisoning
46:20
Speaker 1: our environment with lead. Whoa, So, what's this guy's name
46:23
Speaker 1: who dated the universe and led the charge against lead.
46:27
Speaker 1: His name is Claire Patterson, and he's the one who
46:30
Speaker 1: discovered that we're basically poisoning all of our children with lead.
46:34
Speaker 1: And he came to this discovery because he wanted to
46:36
Speaker 1: know the age of the universe and he was trying
46:37
Speaker 1: to use uranium decaying into lead in order to do it.
46:41
Speaker 1: That is incredible. So we've talked about how uranium is
46:45
Speaker 1: helpful in a lot of different ways, and we're all
46:47
Speaker 1: absolutely in awe of uranus. So now to finally put
46:51
Speaker 1: it all together. So people have sat with us for
46:54
Speaker 1: over fifty minutes and they are waiting for the answer.
46:58
Speaker 1: Is there uranium on uranus? What is the answer? As usual,
47:05
Speaker 1: the answer is we don't really know because we haven't
47:09
Speaker 1: been out there to uranus, so we don't know, but
47:12
Speaker 1: we can fairly confidently say that yes, there is, because
47:16
Speaker 1: uranium seems to be present in almost every piece of
47:19
Speaker 1: rock we find, like afterwards that fall to earth and
47:21
Speaker 1: things that we study. They have these heavy elements in them,
47:24
Speaker 1: and not just uranium, the other heavy elements in varying mixtures,
47:28
Speaker 1: and you can tell something about where these things came
47:30
Speaker 1: from based on like how much iron or how much
47:32
Speaker 1: nickel and various isotopes they have. But uranium is almost everywhere,
47:36
Speaker 1: and so I'm very confident that there is uranium somewhere
47:40
Speaker 1: on Uranus in its rocky core, but we're not sure.
47:44
Speaker 1: And you know, Uranus remains one of the planets that
47:47
Speaker 1: is not very well studied. We only passed it by
47:49
Speaker 1: with a probe once. We've never like dropped anything into
47:52
Speaker 1: it or tried to dive a probe down into it,
47:55
Speaker 1: which I think would be super fun, and you know,
47:57
Speaker 1: maybe there's a big surprise down there. I think that
48:00
Speaker 1: funders should take note, and they should also consider all
48:03
Speaker 1: of the amazing puns and jokes that could be made
48:05
Speaker 1: if we invested in studying this question more. And surely
48:08
Speaker 1: the money is going to come rolling in dow Yeah, exactly.
48:11
Speaker 1: And we have found uranium in other places in the
48:14
Speaker 1: galaxy as well. For example, there's a star nearby called
48:17
Speaker 1: Krel's Star, and it glows and you can tell what's
48:21
Speaker 1: in a star based on how it glows, because every
48:24
Speaker 1: element gets excited by different energy levels and gives off
48:27
Speaker 1: light at unique frequencies as their own fingerprint. So based
48:31
Speaker 1: on the spectrum of a star, you can tell what
48:33
Speaker 1: it's burning. And they have found uranium glowing in this star.
48:36
Speaker 1: Like we haven't gone out to actually visit it in
48:38
Speaker 1: sample it, but we can tell from the light that's
48:41
Speaker 1: coming from this star what's in it. And not just that,
48:44
Speaker 1: but based on the ratio of these various elements uranium
48:47
Speaker 1: and thorium and our knowledge about how they decay, we
48:50
Speaker 1: can use that to age these stars. So uranium is
48:54
Speaker 1: all over the universe and it's telling us lots of
48:56
Speaker 1: fascinating stories about all of the objects that it's hiding inside.
48:59
Speaker 1: And we still have so much left to learning. So
49:01
Speaker 1: thanks very much for coming on this journey with us
49:04
Speaker 1: to learn about uranium and uranus, and thanks to Kelly
49:07
Speaker 1: for coming along and refraining from making that most obvious
49:10
Speaker 1: of jokes the entire hour. Well you're welcome. I've become
49:14
Speaker 1: very mature in my late thirties. Thank you for inviting me.
49:19
Speaker 1: I had a lot of fun, even though I didn't
49:21
Speaker 1: make all the jokes I wanted to make, and everybody
49:23
Speaker 1: out there don't forget to embrace your curiosity and don't
49:26
Speaker 1: lose that childlike wonder ed sense of puns about absurd jokes.
49:31
Speaker 1: They go hand in hand. Thanks everyone, tune in next time.
49:42
Speaker 1: Thanks for listening, and remember that Daniel and Jorge explained.
49:45
Speaker 1: The Universe is a production of I Heart Radio. For
49:48
Speaker 1: more podcast for my heart Radio, visit the I heart
49:51
Speaker 1: Radio app, Apple Podcasts, or wherever you listen to your
49:55
Speaker 1: favorite shows. No