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