Speaker 1: Why are neutrons so complicated? And why is white chocolate
Speaker 1: not more widely hated?
Speaker 2: Are the bananas we eat all the same? Can we
Speaker 2: save them from that fungal strain?
Speaker 1: Is Jupiter really only made of gas? It's definitely got
Speaker 1: a lot of.
Speaker 2: Mess biology, physics, archaeology, forestry. Thanks for not asking about chemistry.
Speaker 1: What diseases do you get from your cat? Well, we'll
Speaker 1: find the answers to all of that.
Speaker 2: Whatever questions keep you up at night, Daniel and Kelly's
Speaker 2: answers will make it right.
Speaker 1: Welcome to another Listener Questions episode on Daniel and Kelly's
Speaker 1: Extraordinary Universe.
Speaker 2: Hello, I'm Kelly Waitersmith.
Speaker 1: I study parasites and s and you are surprisingly good
Speaker 1: at limericks.
Speaker 2: Well, I don't know about that. I gave a talk
Speaker 2: in Kentucky and a woman who is a poet was invited,
Speaker 2: and she gave a poem about our book, and she
Speaker 2: encouraged me to be bolder about poetry and not so
Speaker 2: self conscious. And I know it's not good my rhymes,
Speaker 2: but I have so much fun, and I'm like, that's
Speaker 2: kind of the point for me. For me, that's the point.
Speaker 1: Well, I'm Daniel I'm a particle physicist. I don't pretend
Speaker 1: to be a poet, but I think the universe is
Speaker 1: kind of poetic.
Speaker 2: Ah See, I think you're a poet in your own
Speaker 2: way because you say very poetic things.
Speaker 1: Well, if being corny and curious about the universe counts
Speaker 1: as being poetic, then put me on that list.
Speaker 2: It's a dad kind of poetry.
Speaker 1: Dad poetry. Oh my gosh, science dad poetry. That is
Speaker 1: a new genre we are pioneering here, science parent poetry. Really.
Speaker 2: Yes, Well, you might ask yourself why would Kelly make
Speaker 2: her poems public. I don't really know. I have a
Speaker 2: confidence beyond what I ought to. But you know, there
Speaker 2: are other questions out there, and our listeners have loads
Speaker 2: of them.
Speaker 1: Questions deeper than Kelly's ability to rhyme. We love hearing
Speaker 1: your questions about the universe. How did it begin? How
Speaker 1: is it going to end? What does it all mean?
Speaker 1: How does it come together to explain everything we are
Speaker 1: and everything we eat and all the poems we listen to.
Speaker 1: If you have questions about the nature of the universe
Speaker 1: and you can't find answers, you've been googling, you've been
Speaker 1: asking your neighbors, you don't know any physicists or parasitologists yourself.
Speaker 1: Please write into us to questions at Danielankelly dot org.
Speaker 1: We love, love, love to hear from you, and you
Speaker 1: will definitely hear from us.
Speaker 2: And everybody should have a parasitologist and a physicist in
Speaker 2: their lives, and we are here for you.
Speaker 1: That's right. We are feeling that whole you didn't know
Speaker 1: you had in your life exactly. And so today we
Speaker 1: have a bunch of really fun questions about neutrons, about bananas,
Speaker 1: and about Jupiter, and there's a theme that's going to
Speaker 1: tie them all together. We'll reveal it at the end.
Speaker 2: Oh, Daniel's going to be revealing this to Kelly too,
Speaker 2: because I didn't see a theme well, I was reading
Speaker 2: our outline. Can't wait to find out.
Speaker 1: This first question is from Scott Lewis, who thought that
Speaker 1: neutrons also needed some Daniel and Kelly love after hearing
Speaker 1: our episode about protons.
Speaker 3: Hi, Kelly and Daniel. There have been a number of
Speaker 3: articles lately discussing the internal complexity of the proton and
Speaker 3: everything we are learning about it. One article went so
Speaker 3: far as to describe it as the most complicated thing
Speaker 3: you can possibly imagine. I've read of unusual tetri quark
Speaker 3: configurations and other weird things that show up in the
Speaker 3: colliders from time to time. Is the internal structure of
Speaker 3: a neutron similarly complex? Do we know less about the
Speaker 3: guts of a neutron? And if so, is there a
Speaker 3: reason why they are perhaps more difficult to study? Thank
Speaker 3: you for everything you guys do great job on the program.
Speaker 2: This is a great question. And you know, Daniel, whenever
Speaker 2: I hear about neutrons, I think about one of those
Speaker 2: disaster movies with John Cusack in it, where the world
Speaker 2: was like falling apart because the neutrons had mutated. Yeah,
Speaker 2: I know, I almost walked out of that movie. I
Speaker 2: loved John Cusack as a child of the eighties.
Speaker 1: You know, you can say anything, but don't say anything
Speaker 1: about neutrons mutating.
Speaker 2: That's right, That's a line for me, a line. But
Speaker 2: I gotta say, I don't really understand neutrons very well.
Speaker 2: So let's start at the beginning. What are neutrons? And
Speaker 2: hopefully by the end I'll be convinced that they won't
Speaker 2: mutate and I don't have to worry about the world
Speaker 2: being destroyed.
Speaker 1: Well, I agree with Scott. Neutrons are just as fascinating,
Speaker 1: if not more so, than protons, and they don't get
Speaker 1: as much attention because we don't think of them as
Speaker 1: the building blocks of matter, but they really are. They're essential.
Speaker 1: Without neutrons, we wouldn't have big, complicated atoms that you
Speaker 1: need for biology and chemistry and bananas for example. But
Speaker 1: protons and neutrons are very closely related. Both of them
Speaker 1: are made of the same fundamental objects, just different amounts
Speaker 1: of them. So a proton is made of two upcorks
Speaker 1: and a down cork, and so the upcork is charged
Speaker 1: two thirds and then down cork is charged minus one third.
Speaker 1: So you add two upquarks and a down cork you
Speaker 1: get a total charge of one. That's the proton. If
Speaker 1: you switch one of those upcorks for a down cork,
Speaker 1: and they have one upcork with charge two thirds and
Speaker 1: two down corks with charge minus one third each, you
Speaker 1: get a neutron because it's neutral as zero electric charge.
Speaker 1: So two downs and an up neutron, two ups and
Speaker 1: a down.
Speaker 2: Proton got it. So usually on this show you hear
Speaker 2: me complain about how bad physicists are at naming things
Speaker 2: because we are exactly Yeah, I'm making an accurate observation,
Speaker 2: but I love that y'all have named the thing that
Speaker 2: holds it all together gluons, and I'm assuming that's because
Speaker 2: it sounds like glue, right.
Speaker 1: Well, the gluons aren't very sticky. Yes, yeah, they do
Speaker 1: hold these things together. And so upquarks and down quarks
Speaker 1: are super fascinating because they are similar to other particles
Speaker 1: we know, like electrons, but they also feel another force,
Speaker 1: the strong nuclear force, So they are charged. We talked
Speaker 1: about them having two thirds or negative one third charge,
Speaker 1: so they feel electromagnetism. They can shoot off photons, they
Speaker 1: feel electric fields, but there's another field in the universe
Speaker 1: that they feel that electrons ignore, and that's the color
Speaker 1: field of the strong nuclear force and vibrations of that field.
Speaker 1: They're actually eight different ones are called gluons, and so
Speaker 1: gluons are the mediator of the strong force, the way
Speaker 1: photons are the mediator of the electromagnetic force. It's just
Speaker 1: one of the things the universe can do. And electrons
Speaker 1: have zero color charge, so they just fly through and
Speaker 1: ignore it the way neutrinos, for example, ignore electric fields.
Speaker 1: But quarks they feel all of the fields. The weak feel,
Speaker 1: the strong field, the electromagnetic field, they feel all of them,
Speaker 1: and the strong field is the strongest one, and so
Speaker 1: it binds these particles together very very tightly. So the
Speaker 1: proton and the neutron are both bound together using gluon.
Speaker 2: And is there a history behind gluons that's going to
Speaker 2: like make me think y'all aren't clever or was it
Speaker 2: called gluons because it like seems to glue things together.
Speaker 1: No, we're called the gluons because they glue the nucleus
Speaker 1: together exactly. And there's a whole fascinating history about the
Speaker 1: discovery of gluons and the personalities involved. It was really
Speaker 1: interesting moment with fascinating history. But basically every discovery in
Speaker 1: particle physics has like cool personalities and controversies.
Speaker 2: You would say that as a prominent member of that community.
Speaker 1: They're not always positive stories. You know, there's like arguments
Speaker 1: and people peeing on other people's experiments, and like, you know,
Speaker 1: these are human stories, because hey, physicists are people, you know,
Speaker 1: we're just curious about the universe, and there are Nobel
Speaker 1: prizes at stake, so you don't always get the best
Speaker 1: side of everybody.
Speaker 2: They sure smell like people. You walk up to them,
Speaker 2: you're like, yeah, you're a person. But anyway, okay, one
Speaker 2: day we should get the great story behind gluons. But
Speaker 2: let's talk about how neutrons decay.
Speaker 1: Yeah, so the fascinating thing that neutrons can do that
Speaker 1: protons do not do is that they decay. They don't
Speaker 1: last forever. You have a neutron out there in the universe,
Speaker 1: just by itself, it's gonna turn into a proton. And
Speaker 1: the way it does this is that one of those quarks,
Speaker 1: the dcork, turns into an upcork, so it goes from
Speaker 1: D to up. Now it starts out as a D cork,
Speaker 1: which is charged negative one third, and becomes an upcork,
Speaker 1: which is charged two thirds. So to conserve electric charge,
Speaker 1: it has to emit a negatively charged particle, so it
Speaker 1: emits a W minus which has charged negative one So
Speaker 1: all the charges balance out. So this dcork emits a
Speaker 1: W minus and turns into an upcork, turning the neutron
Speaker 1: into a proton, and then shooting off this W minus particle.
Speaker 2: Okay, so neutron, when it becomes a proton, you get
Speaker 2: a proton and an electron that shoots off.
Speaker 1: You get a W minus, not an electron, but you're close.
Speaker 1: Because the W minus doesn't live for very long. It
Speaker 1: turns into an electron and an anti neutrino, and so
Speaker 1: that's basically the process is the neutron turns into a
Speaker 1: proton in order to balance the charge it has to
Speaker 1: carry along an electron eventually, right, because you start with
Speaker 1: a neutron it's zero charge, you end up with a
Speaker 1: proton with plus one, and you need the electron with
Speaker 1: minus one to balance the electric charges. But the universe
Speaker 1: is not happy with that because the universe also conserves
Speaker 1: the number of electrons. Like, you can't just create electrons
Speaker 1: willy nilly. The universe keeps tabs on that. So if
Speaker 1: you create an electron, you also have to create an
Speaker 1: anti electron or it turns out electron neutrinos also count.
Speaker 1: So if you create an electron and an anti electron
Speaker 1: neutrino at the same time, then everything balances out. You've
Speaker 1: accounted for everything the universe cares about.
Speaker 2: I think the up down quarks give me this maybe
Speaker 2: false sense of understanding what's going on, because I just
Speaker 2: imagine an up arrow and a down arrow and I'm like, oh,
Speaker 2: I got it. You just flip the down arrow. Now
Speaker 2: it's pointing up. But what does it mean to say
Speaker 2: it emits a W minus? Is it just like the
Speaker 2: change in energy gets expelled, and that's what it means
Speaker 2: to say emitting a W minus.
Speaker 1: We really do think about these things as a pair,
Speaker 1: or the up on the top and the D on
Speaker 1: the bottom, And the way we think about it from
Speaker 1: a sort of theoretical point of view is that the
Speaker 1: W is the way to go up or down. So
Speaker 1: there's actually two w's, the W plus and the W minus.
Speaker 1: If you want to go from the D to the U,
Speaker 1: you emit a W minus. If you want to go
Speaker 1: from the U to the D, you emit a W plus.
Speaker 1: So these are sort of like stair steps in order
Speaker 1: to go from one to the other. That's sort of
Speaker 1: the same way around an atom. An electron can go
Speaker 1: up and down energy levels, and to do so, it
Speaker 1: either emits or absorbs a photon. These ws change the
Speaker 1: state from a D to a U, and there is
Speaker 1: a connection to the sort of underlying theoretical structure which
Speaker 1: we usually represent using these things called groups, where you
Speaker 1: can transform an object, but it stays within a little
Speaker 1: pre defined set that's called a group, and so it's
Speaker 1: deeply connected to the sort of group theory structure, which
Speaker 1: I think we should dig into sometime on the podcast.
Speaker 1: But the basic version is that the up is sort
Speaker 1: of the higher state and the down is the lower state.
Speaker 1: But you can move between them using these ws.
Speaker 2: Okay, awesome, all right, I think I get that. Thank you.
Speaker 2: So you can go from neutron to proton. But protons
Speaker 2: don't decay into neutrons. Why do neutrons decay?
Speaker 1: Yeah, great question. Why do neutrons decay and protons don't. Well,
Speaker 1: neutrons have a higher mass than protons, and so when
Speaker 1: a neutron decays, it gives off a little bit of
Speaker 1: energy and turns into a proton. Why does a neutron
Speaker 1: have a higher mass than a proton. Well, remember, the
Speaker 1: mass of these guys comes from the bonds between the quarks.
Speaker 1: It's not because the neutron is made of heavier stuff
Speaker 1: than the protons. These up and down quarks have almost
Speaker 1: no mass, basically zero compared to the mass of the
Speaker 1: proton and the neutron. All of the mass of these
Speaker 1: guys comes from the gluons, the arrangements of the particles,
Speaker 1: and so the neutron state up down down is a
Speaker 1: higher energy configuration than the up, up down proton state,
Speaker 1: and so it's just like a higher energy level the
Speaker 1: way like around an atom. You know, there's like the
Speaker 1: five two S state is a higher energy level than
Speaker 1: like the two P or whatever. There's all these different
Speaker 1: energy levels, and they have to do with the arrangements
Speaker 1: between the particles, the configurations, and so the strong nuclear
Speaker 1: force super duper complicated. But this neutron state, the UDD state,
Speaker 1: is higher energy than the UUD and so it can
Speaker 1: decay down. And that's what the universe does. It always
Speaker 1: starts with massive particles which decay down into lighter particles.
Speaker 1: The proton can't decay because there's nothing lighter than the proton.
Speaker 1: Like you can't find a state that's lighter than the proton.
Speaker 1: If you turned that other D into a U for example,
Speaker 1: it actually would be a higher energy state than the proton.
Speaker 1: So the proton is sort of like the bottom of
Speaker 1: the ladder, the same way the electron is. The muon
Speaker 1: can decay into an electron and other stuff. Why doesn't
Speaker 1: the electron decay because there's nothing for it to decay into.
Speaker 1: It's the lightest particle, and therefore it's stable. Now, we
Speaker 1: don't know that the proton is actually stable, we've just
Speaker 1: never seen it decay, and so we can estimate that
Speaker 1: its lifetime is super duper long because we've watched a
Speaker 1: bunch of protons for a long time to see if
Speaker 1: any of them decay and never seen a single one decay,
Speaker 1: which means either they're totally stable, like they live forever,
Speaker 1: or they live for such a long time that we
Speaker 1: just haven't seen one yet, and that lifetime would be
Speaker 1: like billions and billions of years. So neutrons are super
Speaker 1: fascinating because they actually do decay, so we can learn
Speaker 1: something about what's going on inside them.
Speaker 2: So, in the nucleus of an atom, you have the
Speaker 2: same number of protons and neutrons, but the number of
Speaker 2: protons isn't changing over time, but neutrons are decaying into protons.
Speaker 2: What's gonna happen? Are we eventually not gonna have enough
Speaker 2: neutrons for everything?
Speaker 1: Yeah, this is really amazing because remember we were talking
Speaker 1: about neutrons by themselves. A single neutron in the middle
Speaker 1: of space will decay in about eleven to twelve minutes,
Speaker 1: So you might be wondering, why isn't everything inside me?
Speaker 1: Why aren't all my neutrons turning into protons? And then
Speaker 1: like you know, everything's going haywire because the neutron is stable.
Speaker 1: If it's inside the atom, it's unstable and will decay
Speaker 1: into a proton when it's outside by itself, but inside
Speaker 1: the atom, all of its other neutron and proton buddies
Speaker 1: stabilize it. That's really weird, right, what's going on was
Speaker 1: some really interesting stuff is happening there because when the
Speaker 1: neutrons and the protons are together in the nucleus, they're
Speaker 1: not just like packed in like tennis balls. They're interacting
Speaker 1: with each other. Right, These things are quarks with gluons
Speaker 1: holding them together, but they're not completely sealed off from
Speaker 1: anything else. If you're like on one side of the gluon,
Speaker 1: you might be closer to one of the quarks or
Speaker 1: closer to one of the other quarks. So you can
Speaker 1: actually feel the quarks inside the neutron if you're nearby it.
Speaker 1: And so the atom is not just like a bunch
Speaker 1: of tennis balls totally sealed off. They're interacting with each other.
Speaker 1: There's this little residual strong force that's actually what holds
Speaker 1: the nucleus together.
Speaker 2: Friends help you hold everything together.
Speaker 1: Yes, exactly, And so inside of the nucleus, neutrons can
Speaker 1: live a long long time. Sometimes they can live forever.
Speaker 1: Like take a carbon atom. Carbon has a bunch of
Speaker 1: neutrons in the nuclei. Those neutrons will live forever. You
Speaker 1: have a carbon atom, we think it could just sit
Speaker 1: in space for a zillion zillion zillion years. Other elements
Speaker 1: are not as stable, like uranium, for example, will break down,
Speaker 1: and one of the ways it does is through these
Speaker 1: kind of decays. And so neutrons can either crack open
Speaker 1: your nucleus if they're not quite stable enough, or they
Speaker 1: can help it stay together. Like the reason the nucleus
Speaker 1: stays together all these protons which otherwise are pushing each
Speaker 1: other apart, is because the neutrons are there in between
Speaker 1: you to help stabilize it, to pull them together with
Speaker 1: the strong force, and to keep the protons from pulling
Speaker 1: themselves apart. So neutrons are really the glue that holds
Speaker 1: the whole universe together.
Speaker 2: I feel like you could write nerdy Hallmark cards.
Speaker 1: I love you and your neutrons.
Speaker 2: That's right. You hold me together, you're my proton, you
Speaker 2: keep me from decay. That's right.
Speaker 1: But there's also still a bunch of mysteries about the neutron,
Speaker 1: Like we think we understand the basic story here, but
Speaker 1: you know, particle physicist nerds always want to drill down
Speaker 1: and said, do we really understand it. Let's make a
Speaker 1: bunch of really precise measurements in different ways and see
Speaker 1: if there's anything surprising. So there's this mystery right now
Speaker 1: in exactly how long the neutron does live?
Speaker 2: How do we ask that question?
Speaker 1: So people came up with two very different ways to measure,
Speaker 1: like how long does a neutron take to decay? There's
Speaker 1: the bottle method and the beam method. And the bottle
Speaker 1: method is pretty simple. It says, take a bunch of neutrons,
Speaker 1: cool them down so they're not flying around everywhere, put
Speaker 1: them in a bottle, and then just wait and see
Speaker 1: how many you have, like you know, plot them over time.
Speaker 1: The way we study radioactive decay or any kind of
Speaker 1: random process is you start with a bunch of them
Speaker 1: and you wait to see how long does it take
Speaker 1: until you have half as many and that's the characteristic lifetime.
Speaker 1: And so that's what they do, and they get a number.
Speaker 1: It's like fourteen minutes and thirty nine seconds. It's the
Speaker 1: characteristic lifetime of a neutron. This is a really cool
Speaker 1: experiment they do in Los Alamos, New Mexico, actually my hometown,
Speaker 1: and they have these ultra cold neutrons. They've chilled them
Speaker 1: down to like milli kelvin inside this container they call
Speaker 1: the bathtub. It's like one meter in diameter. They just
Speaker 1: like fill it with neutrons and count them and then
Speaker 1: wait to see what happens. And so they get their number.
Speaker 1: And you know, these are serious dudes. They take it
Speaker 1: very seriously. They've account for all sorts of uncertainty, they
Speaker 1: have cross checks whatever. They're very confident in their number.
Speaker 1: But there's another experiment, the beam experiment, and they don't
Speaker 1: get the same answer.
Speaker 2: What how much does it differ by the.
Speaker 1: Beam experiment makes a neutron beam? And you know we
Speaker 1: said that neutrons decay into protons, right, So they had
Speaker 1: this clever idea like, oh, neutrons are actually really hard
Speaker 1: to count. The other guys have this complicated, sophisticated equipment
Speaker 1: to count neutrons. They're hard. Let's just count the protons.
Speaker 1: If neutrons are decaying into protons, let's just count the protons.
Speaker 1: And so they fly it through an electromagnetic field, filter
Speaker 1: out the protons and count those and they get a
Speaker 1: different answer. They get a slightly longer answer by nine seconds.
Speaker 1: So instead of fourteen minutes and thirty nine seconds, they
Speaker 1: get fourteen minutes and forty eight seconds. So they think
Speaker 1: neutrons live a little bit longer than the bathtub.
Speaker 2: Guys, but don't you have to at least know how
Speaker 2: many neutrons you're starting with, because if you get ten protons,
Speaker 2: but you don't know how many neutrons you started with,
Speaker 2: how do you know the rate of decay?
Speaker 1: Yeah, good question. They know how many neutrons they've started
Speaker 1: with because they know how they produce the neutrons, Okay,
Speaker 1: and so they think they've accounted for that. But you
Speaker 1: know something is going on here, like it's the same process.
Speaker 1: They should get the same answer. So either somebody's made
Speaker 1: a subtle air totally possible, right, and they both work
Speaker 1: really really hard to reduce these uncertainties. Often in this scenario,
Speaker 1: you get two experiments. They get different measurements, but they
Speaker 1: both have large uncertainties and they overlap, and then they
Speaker 1: both work really really hard to refine their experiments, and
Speaker 1: usually as the uncertainty shrink, the results converge into one answer.
Speaker 1: You're like, Okay, cool, the universe is coherent. But what's
Speaker 1: happening here is that the uncertainties are shrinking, but the
Speaker 1: answers are not getting closer together, so they're getting more
Speaker 1: and more confident in their discrepancy, which means, hey, maybe
Speaker 1: there's some new interesting physics. Maybe the neutron, like the
Speaker 1: boring vanilla particle most people aren't excited about, is actually
Speaker 1: the portal to discovering the nature of the universe. You
Speaker 1: all are pros at Silver Linings, Well, this is really
Speaker 1: fun idea that maybe neutrons don't just decay to protons.
Speaker 1: Maybe sometimes neutrons decay into something else, like dark matter,
Speaker 1: and so in the neutron beam, what's happening is these
Speaker 1: neutrons are just disappearing into dark matter, and those guys
Speaker 1: are not measuring it. So maybe the bathtub guys are
Speaker 1: right because they're actually measuring the neutrons, whereas the guys
Speaker 1: who are assuming they turn into protons. They're the ones
Speaker 1: getting the wrong answer because it's not always going to protons.
Speaker 1: Sometimes it's going to dark matter.
Speaker 2: And we can't measure dark matter right.
Speaker 1: We do not have ways to measure dark matter is
Speaker 1: certainly not in these beams, and so this is really
Speaker 1: interesting and really important because it could be an indication
Speaker 1: of something that's happening. And it's also important because it
Speaker 1: helps us understand the early universe. You know, in the
Speaker 1: very early universe, we had like quarks and gluons flying
Speaker 1: around and things cool down into hydrogen and briefly also
Speaker 1: forming some helium. And that ratio of hydrogen helium is
Speaker 1: super important because it tells us something about the density
Speaker 1: of quarks at that time and what the early universe
Speaker 1: was really like. And we need neutrons in order to
Speaker 1: form helium, Like you can't form helium without neutrons. You
Speaker 1: can just squeeze protons together. You have to have those
Speaker 1: neutrons to facilitate. But if the neutrons decay a little
Speaker 1: bit faster than they aren't around as long to make helium.
Speaker 1: If neutrons decay slower, there are more of them to
Speaker 1: stick around and make helium. More helium means smaller, longer
Speaker 1: lasting stars, so it has this cascading effect on the
Speaker 1: whole history of the universe. Super fascinating anyway, neutrons really amazing.
Speaker 1: Thank you very much Scott for asking about this, and
Speaker 1: I hope that we've answered all of your questions about
Speaker 1: neutrons and inspired new ones. Let's hear what Scott has
Speaker 1: to say about our story of neutrons.
Speaker 3: Hi, Daniel and Kelly, thank you for the thoughtful answer.
Speaker 3: It seems like the neutron has a pr problem and
Speaker 3: I'm just not.
Speaker 1: Okay with that state of affairs.
Speaker 3: Neutrons do some very cool and rather important things and
Speaker 3: the world really needs to know. As a follow up question,
Speaker 3: if a free neutron decays in a matter of minutes,
Speaker 3: does that imply that the study of neutron guts is
Speaker 3: practically more difficult than the study of proton guts. Thanks
Speaker 3: again for everything you guys do.
Speaker 1: Great question. Well, we can study neutrons because there are
Speaker 1: lots of them, but seeing them fall apart is actually
Speaker 1: useful because it gives us something to measure, to predict,
Speaker 1: to calculate. Protons, on the other hand, just sit there,
Speaker 1: so we have to do some work to smash them
Speaker 1: or poke them to learn anything. So neutrons are actually
Speaker 1: being helpful, all right.
Speaker 2: So I gotta tell you, I'm on the edge of
Speaker 2: my seat trying to figure out what ties together all
Speaker 2: of the three questions that we got today. It's still
Speaker 2: not clear to me other than the fact that, like,
Speaker 2: bananas are made of protons and neutrons.
Speaker 1: Hmmmm?
Speaker 2: Is that it was it that simple?
Speaker 1: No more than that.
Speaker 2: It's gotta be more than that, Okay, So our next
Speaker 2: question is about bananas. Matt from Discord had this question.
Speaker 4: Hi, Danielle Kelly, this is Matt from Indiana. I was
Speaker 4: walking through the grocery store and notice there are all
Speaker 4: sorts of varieties of peppers, red green, tiny, big yellow orange,
Speaker 4: tons of apple varieties, red delicious, Granny Smith. And then
Speaker 4: I got to the bananas, just bananas, plain bananas, no
Speaker 4: matter where I go. And then I found out that
Speaker 4: most bananas we eat are banana clones. So why banana
Speaker 4: clones and not from seeds is what I'm curious of.
Speaker 4: Thanks at advance, and thanks for giving me an excuse
Speaker 4: to say bananas way too many times.
Speaker 2: Oh man. So I was excited to have an opportunity
Speaker 2: to read more about bananas. So let's start with banana reproduction.
Speaker 2: Bananas can reproduce in two different ways. They reproduce sexually
Speaker 2: by making seeds, and they reproduce asexually by producing suckers.
Speaker 1: Hold on, wait, I have a question already. Okay, great,
Speaker 1: First of all, bananas reproduce or banana trees reproduced, right,
Speaker 1: because the bananas themselves are just part of the banana tree.
Speaker 2: Right, Yeah, yeah, yes, you're right. You're right. I was
Speaker 2: being lazy with my words, although I'm gonna call you
Speaker 2: on it, because bananas aren't really trees. I think technically
Speaker 2: they're curves.
Speaker 1: Really, do you remember one of.
Speaker 2: Our other episodes we were talking about the anatomy of
Speaker 2: the tree and how it forms rings. Bananas are just
Speaker 2: taxonomically distantly related. They don't form that way. They just
Speaker 2: kind of have like a stalk that's really trunk and
Speaker 2: tree like in the middle. But they're not like typical trees.
Speaker 1: Well, all right, so banana trees are not trees. I've
Speaker 1: already learned something. And what part of the plant is
Speaker 1: the banana? Is it fruit the way an apple? Is
Speaker 1: this just something else weird? I remember strawberries or something
Speaker 1: totally different. Which part of the plant are we actually
Speaker 1: snacking on?
Speaker 2: It is the fruit?
Speaker 1: Okay?
Speaker 2: Yeah, yeah, what do you mean by strawberries aren't really
Speaker 2: the fruit? I'm confused.
Speaker 1: Didn't we do an episode where like strawberries are actually
Speaker 1: the seed or something? I don't remember I remember, I
Speaker 1: mean something surprising about.
Speaker 2: Strawberry Strawberry seeds are on the outside, which is atypical.
Speaker 2: But was that the whole fact?
Speaker 1: Anymore? Biology doesn't stay in my head as long as
Speaker 1: physics stock.
Speaker 2: No, busted, Let's get away from this.
Speaker 1: So back to bananas. Bananas are the fruit, but they're
Speaker 1: not technically growing on trees, because I thought fruit had
Speaker 1: to grow on trees.
Speaker 2: No, I mean like strawberries aren't growing on trees.
Speaker 1: Hmmm, all right, cool.
Speaker 2: Although I guess maybe we're not quite sure if strawberries
Speaker 2: are fruits. We're all confused today.
Speaker 1: I'm not sure. It doesn't mean people aren't show Okay,
Speaker 1: got it, I got it. I'm far for an expert.
Speaker 1: All right, So bananas can reproduce sexually or asexually.
Speaker 2: You were telling us yes, And so what happens with
Speaker 2: the asexual reproduction is that the giant stalk that looks
Speaker 2: like a trunk at the bottom underground. In addition to
Speaker 2: its roots, it's producing what are called suckers. And these
Speaker 2: suckers come out from the mother plant and pop up
Speaker 2: along the sides, and they are essentially just clones of
Speaker 2: the mom and they'll stay connected for a while, but
Speaker 2: you can cut them off, move them somewhere else, and
Speaker 2: now you've got a new banana plance.
Speaker 1: And why do biologists call them suckers? I mean that
Speaker 1: makes me think of the things on an octopus's tentacle.
Speaker 1: Are these like an octopus tentacles sticking out through the
Speaker 1: ground or what's going on here? Do they suck in
Speaker 1: some way?
Speaker 2: I don't know the history, but it's just a much
Speaker 2: more fun name than any of you guys would have
Speaker 2: come up with. I'm kidding. Glue ones is a great name.
Speaker 1: I wish we had called some particle the suckers. That
Speaker 1: would have been really fun.
Speaker 2: You might discover a new particle, and I think that's
Speaker 2: what you should name it.
Speaker 1: In the suckers beam, that's right. So they can basically
Speaker 1: clone themselves, make mini versions, or they can actually get
Speaker 1: it on with their neighbors.
Speaker 2: That's right. And there's something like a thousand species of
Speaker 2: plant that could be called banana plants. Oh, so it's
Speaker 2: a lot of diversity. But at some point in the past,
Speaker 2: so like bananas don't fossilize, so it's hard to know
Speaker 2: exactly when humans started eating bananas, but way before written
Speaker 2: records were a thing for our species. What we think
Speaker 2: happened was that a banana plant had a mutation and
Speaker 2: it didn't produce seeds. And you would know if your
Speaker 2: banana had seeds in it because the seeds produced by
Speaker 2: lots of banana plants are big and hard, and it
Speaker 2: would be very unpleasant to eat a banana with seeds
Speaker 2: in it. And so bananas don't have seeds. And some
Speaker 2: human must have found this tree and they were like, oh,
Speaker 2: this is solid. There's nothing that cracks my teeth in
Speaker 2: this plant, and so they took the suckers and that
Speaker 2: got propagated.
Speaker 1: But this is like prehistory because we don't have records
Speaker 1: of it. We don't know when this happened, that's right, Yeah,
Speaker 1: So could it also have been the product of like
Speaker 1: human breeding. We found like a plant with smaller seeds
Speaker 1: and another one that crossbred them and pushed them in
Speaker 1: that direction. Or do you think it's more likely it's
Speaker 1: just like one random mutation.
Speaker 2: Artificial selection could have helped it along. I believe our
Speaker 2: understanding is that this happened before humans really had enough
Speaker 2: of an understanding to engage an artificial selection on purpose.
Speaker 1: Wow.
Speaker 2: But it certainly could have been the case that Joe
Speaker 2: had a plant that had two seeds in it and
Speaker 2: Sally had a plant that only had one, and everybody
Speaker 2: wanted the suckers from Sally's plant. That's way better, and
Speaker 2: over time that process could have played out. But I
Speaker 2: don't think it was purposeful initially.
Speaker 1: And so that was the last sexual reproduction of these
Speaker 1: bananas that were eating in every reproduction of banana trees
Speaker 1: since that moment has been asexual.
Speaker 2: So my understanding is that there have been strains that
Speaker 2: have arisen through this process. So it didn't necessarily happen
Speaker 2: just once. It could have happened in like five different
Speaker 2: banana trees in different areas, and now you've got these
Speaker 2: different clonal lineages. But there's still all of those wild
Speaker 2: banana species out there that are still producing seeds.
Speaker 1: I see.
Speaker 2: Okay, So around the nineteen hundreds, there was a strain
Speaker 2: of bananas called the gro Michelle, which means big mic.
Speaker 1: It sounds so much fancier inference.
Speaker 2: It does. But the big mic was everywhere, and I'm
Speaker 2: gonna bum everybody out, which is exactly what everybody expects
Speaker 2: from me. Apparently the grow michelle bananas tasted better than
Speaker 2: the bananas we have now.
Speaker 1: Whoa.
Speaker 2: But they were all clones, and so these were being
Speaker 2: grown all over the world. Bananas were getting huge, They're
Speaker 2: being shipped all over the world, and a fungal infection
Speaker 2: broke out, and because all of the gro michells were clones,
Speaker 2: they were all susceptible and it decimated the bananas around
Speaker 2: the world. Socker, blue Blue, We're sorry, French speakers.
Speaker 1: Wait, do you know what the kro Michelle tasted like?
Speaker 1: Do we have like written records or living people who
Speaker 1: have eaten them who can tell us about this banana
Speaker 1: that none of us will ever eat.
Speaker 2: There probably are some people still alive who have eaten it.
Speaker 2: I think it was just a sweeter tasting banana than
Speaker 2: what we have now.
Speaker 1: I know, the lost bananas, I know.
Speaker 2: My gosh, it is said, it is said.
Speaker 1: Is there somebody out there who's like going to de
Speaker 1: extinctify the Groa michelle. That sounds like a billion dollar
Speaker 1: idea right there.
Speaker 2: Yeah, so there might be someone who's still maintaining the
Speaker 2: suckers from the Groa michelle in some lab somewhere, but
Speaker 2: it remains susceptible to Panama disease, which is what we
Speaker 2: call this fungal disease that wiped out the bananas. So
Speaker 2: somebody maybe could bring it back. But when the Gromychelle declined,
Speaker 2: the Cavendish arose, and the Cavendish must have just been
Speaker 2: a slightly different strain that happened to be resistant to
Speaker 2: the dominant fungal strain at the time, and so Cavendish.
Speaker 2: If you live in North America, this is the banana
Speaker 2: that you find on your grocery shelf. So if you
Speaker 2: go to Harris Teeter or you go to Target, or
Speaker 2: you go to Kroger, or you go to Trader Joe's
Speaker 2: or Whole Foods, those are all the same banana genotypes.
Speaker 2: They're clones everywhere you go.
Speaker 1: They all have the same DNA you're saying.
Speaker 2: They all have the same code in their DNA. There
Speaker 2: could be a couple mutations, but they are very similar.
Speaker 1: Wow.
Speaker 2: Amazing In countries like Africa and India, they have a
Speaker 2: greater appreciation for other banana varieties. So there are other
Speaker 2: parts of the world where you can get other kinds
Speaker 2: of bananas, but in the US we get this one.
Speaker 1: I've traveled in Mexico and the grocery store is there.
Speaker 1: They have lots of different kinds of bananas there, like
Speaker 1: little dark red bananas that taste a little bit like strawberries. Whoa,
Speaker 1: you know, big fat bananas, and all sorts of stuff.
Speaker 1: It's a lot of fun.
Speaker 2: Yeah, And plantains are fairly popular in the and I
Speaker 2: think that's another strain where there were no seeds that
Speaker 2: were made and then that got propagated by suckers. But
Speaker 2: in the nineteen nineties, bad news. Oh no, the Cavendish
Speaker 2: gets affected by Panama disease. So this fungal disease has
Speaker 2: continued to evolve while the Cavendish is staying still in
Speaker 2: this evolutionary arms race, because it's just a clone that
Speaker 2: we propagate over and over and over again. And there's
Speaker 2: now a strain of Panama disease that is going after
Speaker 2: the Cavendish bananas.
Speaker 1: Why do they hate us so much?
Speaker 2: I know, I know, fungus is the worst, except.
Speaker 1: When it's helping us make beer and bread and al sorts.
Speaker 2: Of Rather you get me things, you know, I guess
Speaker 2: whenever you say a blanket statement, you're a most always
Speaker 2: going to be wrong.
Speaker 1: Some of them are really fun guys.
Speaker 2: Actually, no, dad jokes, dead poetry. Okay. So now we've
Speaker 2: got Panama disease and it is spreading, and so there's
Speaker 2: some people who will be concerned what happens if the
Speaker 2: Cavendish declines? Do we have something waiting to replace it?
Speaker 2: And the answer is no, no, no, what?
Speaker 1: No? What are those people doing? Get on it? Food scientists.
Speaker 2: There is a lot of money in bananas, so there's
Speaker 2: a lot of people working on it. The first thing
Speaker 2: that they're doing to try to slow the decline is
Speaker 2: biocontrol efforts. So if you go to a major banana
Speaker 2: plantation and you want to go amongst the trees, you
Speaker 2: have to suit up in sterilized clothes, you have to
Speaker 2: put on boots and then walk through a sterilizing solution,
Speaker 2: and you have to do that every time you walk
Speaker 2: from like one plot of bananas to another. Because the
Speaker 2: way the fungus transmits is in the soil. So if
Speaker 2: you get like dirt in your boots and then you
Speaker 2: walk in another area, you can transmit that.
Speaker 1: Wow.
Speaker 2: So it's a pain in the rear end. And like
Speaker 2: every truck that comes in and out has to get sprayed.
Speaker 2: But if they do find a tree that's infected, they
Speaker 2: have to dump fungicides into the soil, kill everything in
Speaker 2: that area, cover it with urea, which I think just
Speaker 2: also changes soil chemistry, making it more likely to kill
Speaker 2: the fungus, cover it with the tarp so that birds
Speaker 2: don't walk on it, and then bring the fungus somewhere else.
Speaker 2: The next zone of plants also get like fungicides and
Speaker 2: herbicides injected into the soil, and then the zone after
Speaker 2: that you have to check, like every month, you have
Speaker 2: to do like a survey to make sure none of
Speaker 2: them have it. And so it's intense.
Speaker 1: Apology is just so hard to control. It's always wriggling
Speaker 1: and squirming out of our control.
Speaker 2: Yes, well, man an invasive species. I feel like it's
Speaker 2: such an interesting conversation about when do you just give up,
Speaker 2: Like it's not worth trying to get starlings out of
Speaker 2: the US anymore. They're not going anywhere.
Speaker 1: They're here anyway, Well, what about bananas? Is there anything
Speaker 1: else we can do? Like, can't we somehow protect our
Speaker 1: bananas or cross them with other wild species or something?
Speaker 2: Yeah, I can hear the panic building in your voice.
Speaker 2: Don't worry. We have a couple options.
Speaker 1: I like banana bread.
Speaker 2: Okay, I know, me too, Me too. Zach makes a
Speaker 2: good banana bread. I don't get in the kitchen, but
Speaker 2: he does a great job. So genetic engineering is one solution,
Speaker 2: and they have in fact added genes from other plants,
Speaker 2: I think tomato to make the cavendish resist to Panama disease.
Speaker 2: And this works, it is resistant. But in the European Union,
Speaker 2: I believe, you're not allowed to sell genetically modified plants.
Speaker 2: And in the United States there's a lot of people
Speaker 2: who feel very squeamish about genetically modified plants, and so
Speaker 2: the industry has decided that this can't be the solution.
Speaker 2: It just would not be financially viable.
Speaker 1: Wow, so he could save the bananas, but still it's
Speaker 1: not good enough.
Speaker 2: Not good enough, And so the last thing that they're
Speaker 2: trying are breeding experiments. So apparently something like one in
Speaker 2: ten thousand bananas will produce a seed. Sometimes it like
Speaker 2: still slips through, so you can search bananas for that
Speaker 2: seed and then cross the Cavendish with other species of
Speaker 2: wild bananas, and so there are some efforts to cross breed.
Speaker 2: But the problem is, like the Cavendish, it's actually an
Speaker 2: absolute marble of a fruit. You know, it comes in
Speaker 2: its own packaging that ripens over the course of a
Speaker 2: week while it is in transit to you, so it
Speaker 2: arrives to you mostly unbruised and now perfectly ready to eat.
Speaker 2: And the various crosses that they've done have produced bananas
Speaker 2: that are like, you know, maybe they're yellow, maybe they
Speaker 2: still have a good you know, outer coating. But so
Speaker 2: far they haven't been able to find anything that meets
Speaker 2: all of their criteria and is delicious. I was reading
Speaker 2: about one banana that looks like a Cavendish and tastes good,
Speaker 2: but it's described as an acid banana, which doesn't sound delicious,
Speaker 2: but it just doesn't taste like the Cavendish. And so
Speaker 2: right now they haven't been able to find anything to
Speaker 2: replace the Cavendish in what some people would say is
Speaker 2: a more sort of natural method. So that's where we are.
Speaker 2: Are we going to have a banana in one to
Speaker 2: two decades. We'll have to wait and see.
Speaker 1: Oh my gosh, our children or our grandchildren might never
Speaker 1: know the tastes of bananas the way we don't know
Speaker 1: the taste of the groamy shell.
Speaker 2: I know it could be traged I mean, think of
Speaker 2: how many babies had bananas as their very first food
Speaker 2: or something like. It could be that my kid's first
Speaker 2: foods were smushed up bananas. My memory is a sieve,
Speaker 2: so I don't know exactly what I fed them the
Speaker 2: first time, but a banana.
Speaker 1: And you know, there's something else fascinating about bananas, which
Speaker 1: is that they are radioactive.
Speaker 2: Is that gonna be the connection?
Speaker 1: Don't give it away, Kelly. Yeah, but yes, inside bananas
Speaker 1: there's naturally occurring potassium forty, which is unstable, and the
Speaker 1: neutrons inside potassium forty decay, And so if you are
Speaker 1: hanging around a banana, it will emit high energy electrons
Speaker 1: and anti neutrinos. Wow, which is technically a radiation.
Speaker 2: Oh would we all be better off without bananas in
Speaker 2: our life?
Speaker 1: I don't know. Bananas contribute to the natural radiation background,
Speaker 1: which I'm sure affects the mutation rate so it's made
Speaker 1: all of us who we are.
Speaker 2: Oh wow, Okay, on that deep dad poetry note. Let's
Speaker 2: find out if Matt found this answer satisfactory. And we'd
Speaker 2: also like to take this moment to thank Matt for
Speaker 2: being an amazing moderator of our discord channel. And if
Speaker 2: you want to join us on discord, go to Daniel
Speaker 2: and Kelly dot org not dot com, although dot com
Speaker 2: appears to be a dead link now because the other
Speaker 2: duel and Kelly got married and their website is down.
Speaker 1: Which means either the wedding went wonderfully and they don't
Speaker 1: care about it anymore, or maybe something didn't go so well.
Speaker 2: Oh man, I'm hoping for the former.
Speaker 1: Yes, good luck Daniel Kelly. Yes, but please do join
Speaker 1: us on the discord with lots of people are asking
Speaker 1: questions and having conversations about science and pizza and all
Speaker 1: sorts of crazy stuff. Go to Danielankelly dot org to
Speaker 1: find the link to join.
Speaker 2: The discord, and let's hear what Matt had to say.
Speaker 4: That answer was beautiful. Thank you so much.
Speaker 5: Now I know more about banana suckers than I've ever
Speaker 5: wanted to know. And also thanks for giving me a
Speaker 5: shout out on the discord for being an administrator there,
Speaker 5: and we really do hope other people will join, just
Speaker 5: like Daniel said, please join us. We'll answer any questions. Yeah,
Speaker 5: have a wonderful day, guys.
Speaker 2: Thanks.
Speaker 1: All right, we're back and we are answering questions from listeners.
Speaker 1: There's a special secret theme of today's podcast that's going
Speaker 1: to tie all of these questions together. Let's see how
Speaker 1: long it takes Kelly to figure it out?
Speaker 2: How many lifetimes?
Speaker 1: The next question is from Steve, who has a question
Speaker 1: about the biggest gaseest planet in the Solar System.
Speaker 2: That isn't Uranus. Sorry I had to.
Speaker 6: Hi, Daniel and Kelly. This is Steve from BC Canada.
Speaker 6: I have a controversial take here. Could it be said
Speaker 6: that there is no such thing as a gas giant
Speaker 6: because these planets have so much pressure that gas becomes liquefied.
Speaker 6: So aren't they really liquid planets? Maybe liquid giants? Sure,
Speaker 6: they are composed of liquid elements that are gaseous to
Speaker 6: earthlings living in earthly pressures, but they are not earth
Speaker 6: and they don't have earthly pressures, so we should be
Speaker 6: calling them liquid giants. Don't you think? I think it's
Speaker 6: about high time that we do a deep dive into
Speaker 6: the inner workings of gas planets. What really are they?
Speaker 1: All right? So Steve is asking a question about the
Speaker 1: science of Jupiter, but also about the name of the
Speaker 1: category that Jupiter finds itself in gas giants. Are they
Speaker 1: really gassy? Should we be calling them liquid giants? These
Speaker 1: are good questions, Steve.
Speaker 2: These are great questions. Yeah, and you gotta tell Jupiter
Speaker 2: and lay off the beans.
Speaker 1: No, No, we're pro beans, even if it makes you gassy.
Speaker 1: Katrina would tell me that beans makes everything better.
Speaker 2: Nobody knows better than Katrina.
Speaker 1: She certainly does. She certainly does, all right, So let's
Speaker 1: dig into it. What in the end is Jupiter made
Speaker 1: out of? Well, Jupiter, like Earth and the Sun, formed
Speaker 1: from this big blob of stuff that the whole Solar
Speaker 1: System was made out of. And you know, the Solar
Speaker 1: system is mostly just the Sun. Like the Sun has
Speaker 1: ninety nine points something percent of all the mass in
Speaker 1: the Solar System. Basically, you have a much larger cloud
Speaker 1: of stuff than our Solar system and others systems formed from.
Speaker 1: But there was in there some seed, some gravitational over
Speaker 1: density that pulled stuff together to form our Solar System,
Speaker 1: and mostly that just collapsed into the center, and most
Speaker 1: of it was hydrogen, because that's what the universe started
Speaker 1: out at. As in fourteen billion years later, were still
Speaker 1: mostly hydrogen, and so the Sun is mostly hydrogen. But
Speaker 1: near the Sun there were also other little areas of
Speaker 1: over density that managed to pull themselves together and hold
Speaker 1: themselves together and resist the Sun's attraction, and that's how
Speaker 1: the planets formed. So you get small rocky planets like
Speaker 1: Earth and the Inner Solar System because the Sun then
Speaker 1: blew away their atmospheres, but far enough out away from
Speaker 1: the Sun, the Sun's radiation didn't blast away all the
Speaker 1: helium and hydrogen, and there was ice out there. Things
Speaker 1: were cold enough to form ice crystals, so you had
Speaker 1: a little bit of an advantage to make bigger planets
Speaker 1: that could grab a little bit more mass. So Jupiter
Speaker 1: is just a scoop of the original protosolar system that
Speaker 1: everything else is made out of.
Speaker 2: So it's a better representation of the protosolar system than Earth.
Speaker 1: Yeah, absolutely, Earth once had an atmosphere of hydrogen the
Speaker 1: way that the Sun does and the way Jupiter does,
Speaker 1: but it was blown away by the early Sun and
Speaker 1: so the Earth is not a great representation of what
Speaker 1: the Solar System is. And actually we're gonna do an
Speaker 1: episode pretty soon about how we know what the universe
Speaker 1: is made out of it And it was a big
Speaker 1: shocker when we discovered that most of the universe is
Speaker 1: not made of the same stuff as the Earth. The
Speaker 1: Earth is an unusual helping of Solar System or universe material.
Speaker 2: Thankfully for us, Yes, exactly, thanks early for us.
Speaker 1: That's why we have bananas. No, that's not the secret theme.
Speaker 1: So Jupiter is mostly hydrogen right by mass. The outside
Speaker 1: is like seventy six percent hydrogen and then twenty four
Speaker 1: percent helium and then just like trace tiny other stuff
Speaker 1: like a little bit of carbon, a little bit oxygen,
Speaker 1: and a little bit of salt for a little bit
Speaker 1: of neon. But the atmosphere, which is just really an
Speaker 1: artificial designation of like a certain layer within Jupiter, is
Speaker 1: mostly hydrogen and helium.
Speaker 2: What would be the arbitrary divider for Jupiter? I do
Speaker 2: think of Jupiter is being just gas all the way through,
Speaker 2: and maybe that's just because it's called a gas giant.
Speaker 2: So what is the dividing line or dividing criteria for
Speaker 2: the atmosphere versus the interior yees.
Speaker 1: So it's a little bit arbitrary, but basically, you have
Speaker 1: layers of stuff that get denser and denser as you
Speaker 1: go in. So you start out the very outer layers
Speaker 1: of Jupiter are cloud layers, and so these are like
Speaker 1: ammonia crystals. There's really high winds, but it's mostly gaseous
Speaker 1: hydrogen with these clouds of ammonia crystals. And that's what
Speaker 1: you see when you look at Jupiter, you know, like
Speaker 1: the rings and the red spot and all this stuff.
Speaker 1: These are like weather patterns in those clouds in the
Speaker 1: very very top layer of Jupiter's atmosphere. But then once
Speaker 1: you penetrate through those layers of clouds, like fifty kilometers
Speaker 1: of clouds or so, below that, there's liquid hydrogen, right,
Speaker 1: And so hydrogen is an atom, but it also forms
Speaker 1: H two, which is a molecule, and then it has
Speaker 1: various phases and it depends on the temperature and depends
Speaker 1: on the pressure. So you start out with gaseous hydrogen
Speaker 1: and then you squeeze it down and you get liquid hydrogen.
Speaker 1: And so this stuff flows, right, it's just denser, and
Speaker 1: so you might say, all right, we're not really in
Speaker 1: the atmosphere anymore, because now we have a liquid and
Speaker 1: you know, here on Earth we consider the atmosphere of
Speaker 1: the gaseous part, and then the surface is where you
Speaker 1: have like solid rock and also liquid. But it's not
Speaker 1: quite so simple on Jupiter because it's not as clear
Speaker 1: and crisp like here on Earth. You know, you have
Speaker 1: liquid and above it is gas, and like if you're
Speaker 1: swimming in the ocean, you can very clearly tell the
Speaker 1: crisp difference. But on Jupiter, they don't really have the
Speaker 1: same distinct transition between liquid and gas, and so you
Speaker 1: have this like gradual transition between gaseous hydrogen and liquid hydrogen.
Speaker 1: What's really going on here is that molecular hydrogen, if
Speaker 1: you look at its phase diagram, there are some pressures
Speaker 1: and temperatures where it's gas and some pressures in temperatures
Speaker 1: where it's liquid. But there's this critical point, this temperature
Speaker 1: and pressure above which it's not really gas and not
Speaker 1: really liquid, and this transition sort of therefore gradual. There's
Speaker 1: this sort of super critical fluid. It's not really technically
Speaker 1: a liquid, it's not really technically a gas that has
Speaker 1: some similarity to both, And so the reason you can't
Speaker 1: just say like, oh, this is the surface of Jupiter
Speaker 1: is that as you descend, it just sort of gets
Speaker 1: denser and denser till eventually it feels like liquid. And
Speaker 1: if you rose back up, it would get less and
Speaker 1: less dense, and then it would just sort of feel
Speaker 1: like gas. But it's a gradual transition rather than an
Speaker 1: abrupt one the way it is here on Earth.
Speaker 2: I see we have yet again accidentally foraid into chemistry,
Speaker 2: but I understand it better now.
Speaker 1: And as you descend, the weather gets really really weird.
Speaker 1: So you get this like helium neon rain. What. Yeah,
Speaker 1: I know, it's really crazy and not something I think
Speaker 1: you should dance and sing in, for example. But this
Speaker 1: is sort of rain like droplets. And what's happening is
Speaker 1: that you have helium and neon the and the upper atmosphere,
Speaker 1: but they come together and form these drops, which then
Speaker 1: sink and depleting the abundance of these elements in the
Speaker 1: upper atmosphere, and they fall down to lower levels of
Speaker 1: the atmosphere. And this is all very speculative. You know.
Speaker 1: There are people who think, for example, like on Saturn,
Speaker 1: there might be conditions that cause diamonds to rain, you know,
Speaker 1: like formation of diamonds in the atmosphere because the intense
Speaker 1: pressure which then fall below. But a lot of this
Speaker 1: is speculative. This is like people running models and thinking
Speaker 1: maybe this is what happens and it's super cool. But
Speaker 1: you know, the big fixture story here is like, we
Speaker 1: really don't understand this stuff. A lot of this is
Speaker 1: just speculation.
Speaker 2: Which is why we need more money to go out
Speaker 2: there and find out definitely do.
Speaker 1: And then things get even weirder as you squeeze it down.
Speaker 1: As you go down further towards the center of Jupiter,
Speaker 1: you're getting higher temperature and higher pressure. Then you reach
Speaker 1: this region where the hydrogen is metallic, right, And metallic
Speaker 1: is a really weird term to apply to hydrogen because
Speaker 1: in astronomy usually they say, well you have helium and
Speaker 1: you have hydrogen. Everything else they call them metal, right,
Speaker 1: So if you talk about the metallicity of stars, it
Speaker 1: means how much of the star is not hydrogen, how
Speaker 1: much of it is not helium, everything else they call
Speaker 1: a metal have a different meaning for what is a metal? Right.
Speaker 1: They're thinking about things where the electrons are flowing because
Speaker 1: the atoms are sort of linked together and the electrons
Speaker 1: are not attached to individual atoms. And that's what we're
Speaker 1: talking about here. This is like the chemical version of
Speaker 1: a metal.
Speaker 2: Does it mean that the atoms are flowing or we're
Speaker 2: using the chemistry definition.
Speaker 1: Now, yeah, we're using the chemistry definition. Because what happens
Speaker 1: is you take those H two molecules, you squeeze them together,
Speaker 1: and the hygen forms something like a lattice. Right, instead
Speaker 1: of having individual H two molecules which have some interaction,
Speaker 1: you know, because of the polarity of them, now you're
Speaker 1: squeezing them together, so the electrons can just jump from
Speaker 1: one hydrogen to another hydrogen to another one. It's like
Speaker 1: a big crystal. It's not quite as tight, but it
Speaker 1: conducts electricity. Right. Normally hydrogen does not conduct any electricity,
Speaker 1: but you squeeze it together, you make it dense enough
Speaker 1: it will conduct. And so it has this like bulk
Speaker 1: lattice phase with delocalized electrons in it. And this is
Speaker 1: something people have been thinking for decades and decades, and
Speaker 1: only the last few years have they been able to
Speaker 1: convincingly make this stuff in the lab by recreating these
Speaker 1: conditions and seeing it actually conduct electricity. So this is
Speaker 1: this huge chunk of Jupiter which is hydrogen squeeze so
Speaker 1: tight that we think it's basically one enormous conductor.
Speaker 2: So when you touch metallic hydrogen, is it hard like
Speaker 2: the metals that I am thinking of, or are we
Speaker 2: still in a sort of like gassy liquidy kind of phase.
Speaker 1: Yeah, great question. Not something we understand super well. But
Speaker 1: I don't recommend you lick it. If somebody has some
Speaker 1: metallic hydrogen, it's hard to imagine what would be like
Speaker 1: to touch it because you can't have it around unless
Speaker 1: it's under very, very high pressure. So it's not like
Speaker 1: somebody could hand you a chunk of metallic hydrogen that
Speaker 1: you could like even consider licking. Okay, it's just going
Speaker 1: to be like super duper dense material.
Speaker 2: Got it, Okay, I don't want to die for this podcast.
Speaker 1: Probably not tasty. I'd recommend a banana for a snack
Speaker 1: instead of metallic hydrogen.
Speaker 2: Wait, hold on, what is the connection then? Is the
Speaker 2: connection that there's a part of Jupiter that's solid like
Speaker 2: a banana and the equipment we used to study neutrons
Speaker 2: as solid too, Daniel, I just don't know.
Speaker 1: Well, Jupiter is active right the same way the Sun is.
Speaker 1: It's a big hot thing and so it radiates. There's
Speaker 1: no fusion going on inside Jupiter, but you know, the
Speaker 1: pressure and the temperature are very high, and so there
Speaker 1: is a lot of radiation being emitted. If you wanted to,
Speaker 1: for example, establish a base on one of the moons
Speaker 1: of Jupiter, you really have to worry about the Jupiter
Speaker 1: win the Jovian winds, very high energy particles shooting at you.
Speaker 1: So just like a banana and just like a neutron,
Speaker 1: you have to worry about radiation if you're going to
Speaker 1: live near any of these things.
Speaker 2: Radiation is the theme.
Speaker 1: It's a particle, of course, I'm not trying to be
Speaker 1: tricky about it.
Speaker 2: Well I got it before the end of the episode almost,
Speaker 2: so bravo Kelly.
Speaker 1: Congratulations. You get a banana. If I had a grow Michelle,
Speaker 1: I would share it with you.
Speaker 2: Oh, thank you.
Speaker 1: So then we can dig down even deeper into Jupiter,
Speaker 1: and eventually you get to stuff that's not hydrogen. So
Speaker 1: we think there's a really thick atmosphere. Metallic hydrogen is
Speaker 1: up to like maybe eighty percent of the radio is
Speaker 1: if you go down to like thirty to fifty percent
Speaker 1: of the radius of Jupiter. There is stuff down there
Speaker 1: that's solid. It's like made of rock, the same kind
Speaker 1: of stuff that the Earth is made out of. And
Speaker 1: it's not small. It's like thirty to fifty percent of
Speaker 1: the radius of Jupiter. It's a really big chunk of
Speaker 1: ice and rock. But you know it's buried under an
Speaker 1: incredibly thick layer of hydrogen. And so if you're really
Speaker 1: hardcore about you could say, well, that's the surface because
Speaker 1: everything else is a gas. It's hydrogen. But you know
Speaker 1: it's not in a gas phase. It's in a metallic phase,
Speaker 1: or it's in a super critical fluid phase. And so
Speaker 1: you could, if you do really deep into Jupiter, stand
Speaker 1: on a rocky quote unquote surface. But I don't think
Speaker 1: you could still call Jupiter a rocky planet.
Speaker 2: All right, yep, I'm giving it to the astronomers. I
Speaker 2: think gas giant is a reasonable name, and also it
Speaker 2: gives many school kids lots of chuckles, and so I
Speaker 2: think it's great.
Speaker 1: Yeah, but it is confusing, right because we call it
Speaker 1: a gas giant because it's mostly made of hydrogen. But
Speaker 1: hydrogen is not always in a gaseous state, and especially
Speaker 1: in Jupiter. Most of the gas on Jupiter is metallic,
Speaker 1: so you could also call it a metallic giant and
Speaker 1: be like, kind.
Speaker 2: Of correct, that does sound cooler.
Speaker 1: It does sound more metal, right, that's right, that's right,
Speaker 1: all right. So I think we've concluded that astronomy names
Speaker 1: are very confusing and maybe there's no way to do
Speaker 1: it right, but it's fun to dig into anyway. And
Speaker 1: so Steve from BC let us know if we answered
Speaker 1: your question about Jupiter.
Speaker 7: Thanks Daniel and Kelly for answering my question. That was
Speaker 7: really insightful to know that Jupiter could be really a
Speaker 7: metal giant. But it makes me think now about how
Speaker 7: we've named Earth. You know, Earth has a lot of
Speaker 7: gas and we depend on that gas. And you know
Speaker 7: how much different is the amount of gas and rock
Speaker 7: ratio than Jupiter. I mean, would it be correct to
Speaker 7: say that Earth is a gas midget? Thanks again for
Speaker 7: answering my question. You're still my favorite podcast. Keep the
Speaker 7: great answers coming, and thank you for being such great
Speaker 7: signs communicators.
Speaker 2: Well, thank you for all of the wonderful questions we
Speaker 2: got today, and we hope to hear from you. Send
Speaker 2: us your questions at Questions at Danielankelly dot org. We
Speaker 2: answer every question, and some of the questions even end
Speaker 2: up on the show.
Speaker 1: We do love to hear from you, and we'd love
Speaker 1: to hear that you are curious that you share our
Speaker 1: passion to understand the universe how it works, from the
Speaker 1: bananas all the way out to the galaxies. So join
Speaker 1: us on the discord. Write to us at questions at
Speaker 1: danielan Kelly dot org. Let us know you're out there.
Speaker 2: Daniel and Kelly's Extraordinary Universe is produced by iHeartRadio. We
Speaker 2: would love to hear from you, We really would.
Speaker 1: We want to know what questions you have about this
Speaker 1: Extraordinary Universe.
Speaker 2: We want to know your thoughts on recent shows, suggestions
Speaker 2: for future shows. If you contact us, we will get
Speaker 2: back to you.
Speaker 1: We really mean it. We answer every message. Email us
Speaker 1: at questions at Danielankelly.
Speaker 2: Dot org, or you can find us on social media.
Speaker 2: We have accounts on x, Instagram, Blue Sky and on
Speaker 2: all of those platforms. You can find us at D
Speaker 2: and K Universe.
Speaker 1: Don't be shy, write to us