Latest / Daniel and Kelly’s Extraordinary Universe / What are the most common elements in the Universe?

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What are the most common elements in the Universe? · Daniel and Kelly’s Extraordinary Universe

• 0:08
  Speaker 1: Hey, Kelly, I've got a weird question for you. You You know,
• 0:12
  Speaker 1: we are going to have to recalibrate weird after all
• 0:15
  Speaker 1: of the strange questions that you asked me on this show.
• 0:18
  Speaker 1: All right, we'll leaves the question what's the most common
• 0:21
  Speaker 1: ingredient in your pantry? Wow? I was expecting you to
• 0:25
  Speaker 1: ask about the ways the universe might incinerate my children.
• 0:28
  Speaker 1: All right, So in the pantry, let's see by volume.
• 0:32
  Speaker 1: Probably flower, thanks to Zack's you know, pandemic baking experiments.
• 0:37
  Speaker 1: I love here and that, but what about like buying number,
• 0:41
  Speaker 1: do you have more bags of flower than like cans
• 0:43
  Speaker 1: of beans? You know? The answer to that is also flower.
• 0:46
  Speaker 1: So we have like loads of weird kinds of flower
• 0:50
  Speaker 1: thanks to all of Zack's baking experiments. So we've got
• 0:52
  Speaker 1: like rye buck wheats, wheats, chickpeas, almonds. If it's been creative,
• 0:59
  Speaker 1: we've probably tried it. We don't have any cricket flower yet.
• 1:02
  Speaker 1: I know that that's you can get that on the market,
• 1:04
  Speaker 1: but almost anything else we've probably tried. Sounds like your
• 1:07
  Speaker 1: family is a flower powered. Okay, flower and butter are
• 1:13
  Speaker 1: the fundamental particles of baking. Maybe I should get to
• 1:16
  Speaker 1: work on a butter collider. See that's the kind of
• 1:19
  Speaker 1: weird thing I was expecting from you. I'm here to
• 1:23
  Speaker 1: live up to your expectations. Bravo. Hi. I'm Daniel. I'm
• 1:42
  Speaker 1: a particle physicist and a professor at UC Irvine, and
• 1:46
  Speaker 1: I really do like colliding butter and flower. I'm Kelly
• 1:49
  Speaker 1: Wayner Smith, a parasitologist with Rice University, and I love
• 1:53
  Speaker 1: consuming the collision of butter and flour. But I tend
• 1:56
  Speaker 1: to stay out of the kitchen for everyone's sake, and
• 1:59
  Speaker 1: give us a sense for how often Zack's baking experiments
• 2:02
  Speaker 1: have a positive outcome. Like when the kids here of
• 2:04
  Speaker 1: dad's baking, are they excited or are they a little worried?
• 2:08
  Speaker 1: They're almost always excited. Zach is actually really good in
• 2:11
  Speaker 1: the kitchen, and most of the time he's not trying
• 2:13
  Speaker 1: to make like healthy foods. He's definitely making like cakes
• 2:17
  Speaker 1: and pies and muffins and very kid friendly things. So yeah,
• 2:20
  Speaker 1: most of the time the outcome of those collisions is good.
• 2:23
  Speaker 1: I see no cricket flour pastry crusts yet. No. No,
• 2:27
  Speaker 1: He's a vegetarian, and I think for him that extends
• 2:29
  Speaker 1: to crickets. All right, and welcome to the podcast. Daniel
• 2:34
  Speaker 1: and Jorge explain the universe, in which we experiment with
• 2:38
  Speaker 1: cooking up the universe into bite sized chunks for you.
• 2:42
  Speaker 1: We want to take everything that's out there in the universe,
• 2:45
  Speaker 1: the crazy black holes, the cosmic swirls of quasars, the tiny,
• 2:49
  Speaker 1: little frothing quantum particles. We want to weave together a
• 2:53
  Speaker 1: story that makes sense to your human brain, because, amazingly, incredibly,
• 2:57
  Speaker 1: we think that the human brain is capable of fashioning
• 3:01
  Speaker 1: stories about the nature of our universe that makes sense
• 3:03
  Speaker 1: to us. That our little mathematical capsules allow us to
• 3:07
  Speaker 1: predict the future, but also to get a sense of
• 3:09
  Speaker 1: explanation and understanding of why the universe is this way
• 3:13
  Speaker 1: and not some other way. My friend and co host
• 3:16
  Speaker 1: or Hey Champ, can't be with us today. He is
• 3:18
  Speaker 1: somewhere in the jungles of Panama, and so we've invited
• 3:21
  Speaker 1: our frequent guest host, Kelly were Smith to join as Kelly,
• 3:23
  Speaker 1: thanks very much for coming on the pot again. I'm
• 3:26
  Speaker 1: excited to be here to cook up brain snacks with you, Daniel.
• 3:32
  Speaker 1: One of the most amazing things to me about brain
• 3:34
  Speaker 1: snacks and real snacks. Is that when we look out
• 3:37
  Speaker 1: in the universe, there's such a huge variety of them.
• 3:39
  Speaker 1: We're lucky to get to eat lots of different kinds
• 3:41
  Speaker 1: of things when we live. You know, so many different
• 3:43
  Speaker 1: kind of fruits and vegetables and pastries filled with incredible stuff.
• 3:47
  Speaker 1: But also just as you look out in the universe,
• 3:49
  Speaker 1: there's just a lot of different kinds of stuff out there.
• 3:52
  Speaker 1: I mean there's like blueberries and plants and bushrooms and
• 3:56
  Speaker 1: iPhones and exploding stars. And you know, if you're trying
• 3:59
  Speaker 1: to tackle the quest and of like what's out there
• 4:01
  Speaker 1: in the universe and how do we make sense of it,
• 4:03
  Speaker 1: there's a lot of different kinds of things to make
• 4:06
  Speaker 1: sense of, right, so much different kinds of things to
• 4:09
  Speaker 1: make sense of. Yes, and as people who have just
• 4:11
  Speaker 1: started gardening, the like production of those things is mind blowing,
• 4:14
  Speaker 1: Like the facts that are chrome soil produces spicy peppers.
• 4:18
  Speaker 1: How does that happen? It is incredible that we have
• 4:22
  Speaker 1: these little biological machines for assembling spicy peppers basically out
• 4:26
  Speaker 1: of dirt, sunlight and air. Right, amazing chemistry done by
• 4:30
  Speaker 1: those plants. Yes, it is amazing. And at the same time,
• 4:34
  Speaker 1: the universe at its smallest level, Like the tiniest little
• 4:37
  Speaker 1: bits that I study in my research seemed to be
• 4:40
  Speaker 1: fairly small in number. I mean, there's just like a
• 4:43
  Speaker 1: few particles that make up everything. We know. You boil
• 4:46
  Speaker 1: down those peppers or your lunch or your husband into particles,
• 4:51
  Speaker 1: then you get a hundred elements, right, that basically make
• 4:54
  Speaker 1: up everything. You tear those apart into protons and neutrons
• 4:58
  Speaker 1: and electrons, and you hair the protons and neutrons apart,
• 5:01
  Speaker 1: and you're down to just like up corks and down
• 5:04
  Speaker 1: corks and electrons. With those three things, you can basically
• 5:08
  Speaker 1: put together everything. So it's a natural sort of philosophical
• 5:11
  Speaker 1: puzzle to understand, Like where does complexity arise? Why isn't
• 5:16
  Speaker 1: the universe just a bunch of really simple combinations of
• 5:19
  Speaker 1: these tiny little bits. Why is it possible to make
• 5:22
  Speaker 1: all sorts of complicated things like kittens and husbands and pies.
• 5:25
  Speaker 1: I'm a little concerned that you suggested boiling down my husband,
• 5:29
  Speaker 1: but I'm interested in the topics, so I'm going to
• 5:31
  Speaker 1: move forward with you here. It's just a thought experiment, right,
• 5:34
  Speaker 1: It's definitely a thought experiment. Nobody should try that at home,
• 5:37
  Speaker 1: either with kittens or husbands. But you know, kittens and
• 5:41
  Speaker 1: husbands and lava do have something really fascinating in common,
• 5:44
  Speaker 1: which is that they're made of the same ingredients. You know,
• 5:48
  Speaker 1: if you take a kilogram of lava and a kilogram
• 5:51
  Speaker 1: of flower, for example, that's only used non living examples
• 5:55
  Speaker 1: for now, then they're made of the same bits, the
• 5:58
  Speaker 1: same up corks and down corks and elect drowns, just
• 6:00
  Speaker 1: put together in different ways. Even if you think about
• 6:04
  Speaker 1: like different elements, different atoms, they're just made out of
• 6:07
  Speaker 1: different numbers of protons and neutrons, but they basically all
• 6:10
  Speaker 1: have the same ratio of one proton to one neutron
• 6:13
  Speaker 1: to one electron. There's not a lot of variation from
• 6:16
  Speaker 1: that in the periodic table, and so everything is just
• 6:19
  Speaker 1: different arrangements of the same stuff. And so by the
• 6:22
  Speaker 1: end of this podcast, I'd like to have a physicists
• 6:25
  Speaker 1: understanding of Carl Sagan's were all star stuff statements? Are
• 6:29
  Speaker 1: you going to give me that by the end of
• 6:31
  Speaker 1: this episode. By the end of the episode, I'm going
• 6:32
  Speaker 1: to give you a recipe to make literally anything in
• 6:35
  Speaker 1: your kitchen. Start with upcuorks and down corks at electrons
• 6:38
  Speaker 1: and you're done. There you go. That's how particle physicists cook,
• 6:42
  Speaker 1: you know, like it's it's some sort of crazy artistic
• 6:44
  Speaker 1: license that all cookbooks don't start at the quarks stage.
• 6:48
  Speaker 1: But what are you going to do with these authors?
• 6:50
  Speaker 1: But it is amazing how many different things you can
• 6:53
  Speaker 1: make out of these basic ingredients, right, It's incredible the
• 6:56
  Speaker 1: complexity that we see out there in the universe, and
• 6:59
  Speaker 1: not even just the biological complexity, but the chemical complexity
• 7:02
  Speaker 1: and the physical complexity. You know, if you started with
• 7:05
  Speaker 1: basic ingredients in your lego set, you can build essentially anything. Right.
• 7:10
  Speaker 1: Having a small number of building blocks but lots of
• 7:13
  Speaker 1: different ways to assemble them does allow you to introduce
• 7:15
  Speaker 1: complexity in the arrangement. But philosophically, it's fascinating to think
• 7:19
  Speaker 1: about what makes you you and what makes lava lava
• 7:23
  Speaker 1: is not the particles that you are made out of,
• 7:25
  Speaker 1: but just how they are put together. That means that,
• 7:28
  Speaker 1: like the information the units of you is somehow just
• 7:32
  Speaker 1: in the relationship between particles, which makes it seem sort
• 7:35
  Speaker 1: of like ineffable. I'd like to imagine that I'm built
• 7:38
  Speaker 1: out of bits of Daniel and you're built out a
• 7:40
  Speaker 1: bit of Kelly, but you're not the Kelly. Noess is
• 7:43
  Speaker 1: really just how those same pieces are put together, and
• 7:46
  Speaker 1: you could have put them together to make somebody else.
• 7:48
  Speaker 1: So I feel like the choice of your example matters
• 7:52
  Speaker 1: so much and whether the story is uplifting or not. So,
• 7:55
  Speaker 1: you know, when you were like, bits of Kelly are
• 7:56
  Speaker 1: sort of like lava, I'm like, oh, that's that's kind
• 7:59
  Speaker 1: of a downer. But you know, like as a biologist,
• 8:02
  Speaker 1: if you're like, oh, the bird in the sky you
• 8:04
  Speaker 1: share bits with that, that's sort of a beautiful idea,
• 8:06
  Speaker 1: although maybe a geologist would be like, tone it down, Kelly,
• 8:09
  Speaker 1: Lava is great. Yeah, you'd like to be compared to
• 8:11
  Speaker 1: a pigeon rather than lava. I mean, pigeons are basically
• 8:13
  Speaker 1: sky rats. You know. Rosemary Moscow wrote a great book
• 8:17
  Speaker 1: on pigeons recently and turns me around on pigeons, and so, yes,
• 8:20
  Speaker 1: I'm fine with being a pigeon. I love rats, though
• 8:23
  Speaker 1: I don't say sky rats as a negative description. You know,
• 8:26
  Speaker 1: we used to have rats living with us. They're wonderful pets,
• 8:28
  Speaker 1: very smart. So I'm also pro pigeons, but I gotta
• 8:31
  Speaker 1: say I'd rather be compared to lava. Lava is definitely
• 8:33
  Speaker 1: hotter than pigeons, and that's the measure for goodness in
• 8:36
  Speaker 1: your life. What has the highest temperature? Hey, you gotta
• 8:40
  Speaker 1: go with some quantifiable metric, right, So does it make
• 8:43
  Speaker 1: the sun the best? The Sun is pretty cool? Actually,
• 8:46
  Speaker 1: you know, there are definitely hotter things in the universe,
• 8:49
  Speaker 1: the interiors of new drawn stars, for example, cork gluon
• 8:52
  Speaker 1: plasmas created the large Hadron collider, or hotter than the
• 8:55
  Speaker 1: center or the service of the Sun. So maybe that
• 8:59
  Speaker 1: should be my point of reference. Perhaps, perhaps, But today
• 9:02
  Speaker 1: we are not interested in diving deep to understand the
• 9:05
  Speaker 1: core fundamental nature of reality and its materials, tearing apart
• 9:09
  Speaker 1: the upcork and down cork into the basic bits that
• 9:11
  Speaker 1: they might be made out of. We're going to do
• 9:13
  Speaker 1: something a little different. We're going to take a step
• 9:15
  Speaker 1: back and try to understand how those things come together
• 9:19
  Speaker 1: to make the amazing complexity and variety that we do
• 9:22
  Speaker 1: see in our universe. Because even if the elements of
• 9:26
  Speaker 1: the periodic table are not a fundamental description of the universe,
• 9:30
  Speaker 1: there are pretty important part of our lives. You get
• 9:33
  Speaker 1: too much mercury in your breakfast, cereal your life is
• 9:35
  Speaker 1: going to be different. You are built out of carbon
• 9:38
  Speaker 1: and you breathe oxygen. These things are important to understanding
• 9:42
  Speaker 1: how life starts in the universe and where life can
• 9:44
  Speaker 1: go if it wants to move to different places in
• 9:46
  Speaker 1: the universe, exactly. And so if you're interested in building kittens,
• 9:50
  Speaker 1: or baking pies or assembling podcast hosts, then you want
• 9:54
  Speaker 1: to know where you can find the ingredients. And so
• 9:57
  Speaker 1: today on the podcast, we'll be answering exactly that question.
• 10:00
  Speaker 1: We're gonna be talking about what elements are most common
• 10:09
  Speaker 1: in the universe. And we said a minute ago that
• 10:12
  Speaker 1: everything is made out of up corks and down corks
• 10:14
  Speaker 1: and electrons, and so you might get the sense that
• 10:16
  Speaker 1: it doesn't really matter, but there is an important categorization here.
• 10:20
  Speaker 1: When you put the upcorks and down corks together to
• 10:22
  Speaker 1: make protons and neutrons, and you put those together to
• 10:26
  Speaker 1: make elements, we tend to count those by the number
• 10:29
  Speaker 1: of protons inside the nucleus. Right, So if you have
• 10:33
  Speaker 1: just like a proton with one electron around it, that's hydrogen.
• 10:37
  Speaker 1: You can add a neutron to it. You still call
• 10:39
  Speaker 1: that hydrogen, right, it's a little bit different. You've added
• 10:41
  Speaker 1: a neutron, but you still call it hydrogen. It's like,
• 10:44
  Speaker 1: neutrons aren't as important as the proton and the electron,
• 10:49
  Speaker 1: but if you add another proton to it, then boom,
• 10:51
  Speaker 1: it's another element. It's helium because now in order to
• 10:54
  Speaker 1: make it neutral, you also need another electron. And that's
• 10:58
  Speaker 1: the key. The reason that we count things as different
• 11:01
  Speaker 1: elements when you add a proton but not a neutron,
• 11:04
  Speaker 1: is that you also have to add that electron, and
• 11:06
  Speaker 1: that change is fundamentally the chemical behavior of the thing
• 11:10
  Speaker 1: in a dramatic way, because now the bonds that conform
• 11:13
  Speaker 1: are different, and its reactivity and whether it emits light
• 11:16
  Speaker 1: or absorbs, like whether it likes to stick to stuff
• 11:19
  Speaker 1: or not, really changes. And so while like hydrogen and
• 11:22
  Speaker 1: deuterium are different, adding a neutron to that proton does
• 11:26
  Speaker 1: change it, it's not as big a change as adding
• 11:28
  Speaker 1: a proton. So we tend to categorize this stuff in
• 11:31
  Speaker 1: the universe by the number of protons in the nucleus.
• 11:34
  Speaker 1: So it's adding another proton means you have to get
• 11:36
  Speaker 1: another electron. Why don't we categorize things by the number
• 11:40
  Speaker 1: of electrons that are in there? A great unanswered question
• 11:44
  Speaker 1: in the history of science. I think it's probably because
• 11:47
  Speaker 1: protons are more massive, and so we used to before
• 11:51
  Speaker 1: we understood what was inside these things, we used to
• 11:54
  Speaker 1: categorize these things by atomic mass, just like how heavy
• 11:58
  Speaker 1: is a mole of these atoms, and that's account of
• 12:01
  Speaker 1: the number of protons and neutrons together, and so all
• 12:04
  Speaker 1: we could measure was sort of the atomic mass and
• 12:06
  Speaker 1: the overall charge. So I think it probably comes down
• 12:09
  Speaker 1: just to a bias in terms of the protons because
• 12:11
  Speaker 1: they're heavier and they also contribute to the atomic mass.
• 12:15
  Speaker 1: But you know, the pro electron folks have a good argument,
• 12:18
  Speaker 1: Oh that is that still a live debate. No. I
• 12:21
  Speaker 1: would like to imagine that there's like an ancient Victorian
• 12:24
  Speaker 1: society out there that feels like electrons have been overlooked,
• 12:27
  Speaker 1: got it? And I mean, I'm sure there's still somebody.
• 12:29
  Speaker 1: Everyone's got their thing. But the fascinating thing when you
• 12:32
  Speaker 1: look out into the universe is that we don't see
• 12:35
  Speaker 1: all of these elements in equal numbers. You don't have
• 12:37
  Speaker 1: as much uranium in the universe as you do nickel,
• 12:41
  Speaker 1: or as much nickel as you do hydrogen, for example.
• 12:44
  Speaker 1: And understanding where all these things come from, requires you
• 12:47
  Speaker 1: to do a deep dive into the history of the
• 12:50
  Speaker 1: universe itself and to understand how all of these things
• 12:53
  Speaker 1: come together. What engines there are out there in the
• 12:56
  Speaker 1: universe capable of manufacturing these cre easy elements. Let's see
• 13:01
  Speaker 1: what the audience thought. The answer was yes, So as usual,
• 13:04
  Speaker 1: I went out there to our cadre of volunteers to
• 13:07
  Speaker 1: ask them if they knew what the most common elements
• 13:10
  Speaker 1: in the universe were. If you like to participate in
• 13:13
  Speaker 1: this segment of the podcast and contribute your uneducated speculation
• 13:18
  Speaker 1: for our entertainment purposes only, then please write to me
• 13:21
  Speaker 1: two questions at Daniel and Jorgey dot com. We'd love
• 13:24
  Speaker 1: to hear your voice on the podcast. So think about
• 13:27
  Speaker 1: it for a minute. Do you know which elements are
• 13:30
  Speaker 1: most common in the universe? Here's with some of our
• 13:33
  Speaker 1: listeners had to say. First of all, I have a
• 13:35
  Speaker 1: fundamental lack of understanding of the periodic table and what
• 13:39
  Speaker 1: an element actually is. But let I guess hydrogen and
• 13:44
  Speaker 1: maybe helium. I don't know. I think hydrogen is the
• 13:47
  Speaker 1: most common that's kind of everywhere because it's the one
• 13:51
  Speaker 1: with it's you know, it's number one on the periodic
• 13:54
  Speaker 1: table when it's absolutely everywhere, and I think the next
• 13:57
  Speaker 1: one is helium, which is number two. AT don't if
• 14:00
  Speaker 1: it then continues, and I know that as atoms get
• 14:03
  Speaker 1: more protons and neutrons and they get heavier, they become
• 14:06
  Speaker 1: less common, I think, but definitely hydrogen. I think it's
• 14:09
  Speaker 1: dark marter. I don't know if it's really an element
• 14:12
  Speaker 1: that you are thinking about. What's the definition of an
• 14:15
  Speaker 1: element in that case? I don't know. The most common
• 14:18
  Speaker 1: elements in the universe is hydrogen, and because of the
• 14:23
  Speaker 1: way fusion works, I think after that is helium. If
• 14:27
  Speaker 1: I remember correctly, I think the most abundant elements in
• 14:31
  Speaker 1: the universe is hydrogen, helium, and oxygen and maybe carbon.
• 14:37
  Speaker 1: So basically just a few elements on top of the
• 14:40
  Speaker 1: periodic table. The most common universe should be hydrogen and helium.
• 14:47
  Speaker 1: But hydrogen by far and oxygen too added then that
• 14:54
  Speaker 1: is dark mellon element. We don't know, but that should
• 14:58
  Speaker 1: be the top three elements. Stuff we know, and we're
• 15:01
  Speaker 1: getting direct with I think in terms of all the
• 15:04
  Speaker 1: question and answer sessions that I've been around for on
• 15:07
  Speaker 1: this podcast, this is the one that had the most
• 15:09
  Speaker 1: consistency in the answers, it seems like most people you
• 15:13
  Speaker 1: know argued it was hydrogen, followed by helium. But then
• 15:17
  Speaker 1: there was some question about dark matter and whether it
• 15:19
  Speaker 1: counts as an element or not, and I think that
• 15:23
  Speaker 1: the answer is no. But yeah, what did you think
• 15:25
  Speaker 1: of these answers? Yeah, I was very glad to see
• 15:28
  Speaker 1: that everybody knew the basic story that hydrogen is the
• 15:31
  Speaker 1: most common thing out there, and we even heard some
• 15:34
  Speaker 1: ideas about why and how these things are made, and
• 15:37
  Speaker 1: so I was very pleased to hear that. I also
• 15:39
  Speaker 1: love the legalistic loophole of like, dark matter, is that
• 15:42
  Speaker 1: a thing? Is that an element? Does that count? When
• 15:44
  Speaker 1: you really ask me, is this a trick question? There's
• 15:46
  Speaker 1: a little bit of paranoia there. Is he trying to
• 15:50
  Speaker 1: kill me? That's the other question I think when I
• 15:52
  Speaker 1: talked to you exactly, because it's important to remember that
• 15:54
  Speaker 1: when we talk about elements, we're talking about atomic matter.
• 15:57
  Speaker 1: We're talking about things made out of adam. But in
• 16:00
  Speaker 1: the larger accounting of the universe, atomic matter is less
• 16:04
  Speaker 1: than five percent of the energy density of the universe.
• 16:08
  Speaker 1: If you take like a cubic light year of the
• 16:10
  Speaker 1: universe and you add of all of the energy in there,
• 16:14
  Speaker 1: then like seventy percent of the energy in that chunk
• 16:17
  Speaker 1: of the universe is devoted to dark energy, which contributes
• 16:21
  Speaker 1: to the accelerating expansion of the universe. Something like twenty
• 16:24
  Speaker 1: five percent is dark matter, some weird kind of stuff
• 16:27
  Speaker 1: that's out there, but it's invisible and almost intangible, so
• 16:31
  Speaker 1: it's hard to know exactly what it's made out of.
• 16:33
  Speaker 1: And the rest of it. This five percent is the
• 16:35
  Speaker 1: kind of stuff we're talking about today that I'm made
• 16:38
  Speaker 1: out of, and you are made out of, and kittens
• 16:39
  Speaker 1: are made out of, and pastry crusts are made out of.
• 16:42
  Speaker 1: Atomic matter. Things build out of protons, neutrons, and electrons,
• 16:46
  Speaker 1: and in understanding what flavor of those elements we have
• 16:49
  Speaker 1: and in what proportion, we're gonna understand a lot about
• 16:51
  Speaker 1: the history of the universe and also the role that
• 16:53
  Speaker 1: dark matter played in shaping this universe. Even though we
• 16:56
  Speaker 1: currently don't think that dark matter itself is made of atoms,
• 17:00
  Speaker 1: so that means it doesn't have any quarks, so like
• 17:02
  Speaker 1: even one level lower dark matter doesn't have that either. Yeah,
• 17:05
  Speaker 1: we think that dark matter is made of something else,
• 17:07
  Speaker 1: not quarks, not electrons, something totally different. And weird a
• 17:11
  Speaker 1: completely different kind of particle, or maybe not even a particle,
• 17:16
  Speaker 1: or maybe many different kinds of particles, or maybe tiny
• 17:20
  Speaker 1: cosmic kittens. I mean, we're kind of a little bit clueless.
• 17:22
  Speaker 1: You might get the sense I'm hoping for the cosmic kittens.
• 17:26
  Speaker 1: So you mentioned hydrogen is the most common thing in
• 17:29
  Speaker 1: the universe by atoms or that we're gonna be talking
• 17:32
  Speaker 1: about today. Where is that coming from? And hydrogen is
• 17:36
  Speaker 1: the most common thing in the universe, and it's not
• 17:38
  Speaker 1: even close, like not even a little bit. It's a
• 17:41
  Speaker 1: pretty good approximation to say the universe is hydrogen. If
• 17:45
  Speaker 1: you just said everything in the universe was hydrogen, you'd
• 17:47
  Speaker 1: be getting correct, which is, hey, that's an a right,
• 17:51
  Speaker 1: So you can just like move on. That's your description
• 17:54
  Speaker 1: of the universe. You're done. You're satisfied with your grade.
• 17:57
  Speaker 1: So that means that like, of the atoms that exist
• 17:59
  Speaker 1: in the universe, of them have only a single proton, right,
• 18:04
  Speaker 1: And it's incredible, like most of the universe hydrogen. It's
• 18:08
  Speaker 1: really just a tiny little bit Like the rest of
• 18:10
  Speaker 1: the universe is just like the spice in the recipe,
• 18:12
  Speaker 1: and so like, as a biologist always think about parsimony,
• 18:15
  Speaker 1: and so to me, I feel like, well, maybe that
• 18:17
  Speaker 1: makes sense because like the one proton doesn't need to
• 18:19
  Speaker 1: find anything else or bind up with anything else, and
• 18:21
  Speaker 1: so maybe just like it's easiest to get one proton
• 18:25
  Speaker 1: and that's why you've got a lot of it. But
• 18:27
  Speaker 1: that's not the answer at all, is it. No, that's
• 18:29
  Speaker 1: actually exactly the answer, right. It's the simplest thing you
• 18:32
  Speaker 1: can do with these particles that is stable. And so
• 18:35
  Speaker 1: the critical thing to understand is like, well, where do
• 18:37
  Speaker 1: any elements come from? You know, are they just like
• 18:40
  Speaker 1: created during the Big Bang or the same level? How
• 18:43
  Speaker 1: does this actually come together? How do you make elements
• 18:45
  Speaker 1: from the sort of early universe cosmic soup? Where do
• 18:49
  Speaker 1: they emerge? And so in understanding that story, you'll understand
• 18:52
  Speaker 1: very quickly why basically almost all started as hydrogen and so,
• 18:57
  Speaker 1: you know, going way back to the very very beginning,
• 18:59
  Speaker 1: before they was any atoms, any even corks, any elements
• 19:03
  Speaker 1: at all. Go back to like the pre Big Bang, right,
• 19:06
  Speaker 1: what was the universe at the very very beginning, Well,
• 19:09
  Speaker 1: there was some hot and dense state something. We don't
• 19:12
  Speaker 1: know what it was really at all, We just know
• 19:14
  Speaker 1: that it had a lot of energy, and it was
• 19:16
  Speaker 1: hot and dense. And a common misperception about the Big
• 19:19
  Speaker 1: Bang is that it was already like a tiny dot
• 19:22
  Speaker 1: of stuff which then exploded out into the universe. But instead,
• 19:26
  Speaker 1: the modern perception of the sort of pre Big Bang
• 19:28
  Speaker 1: early universe is that the universe was already filled with stuff.
• 19:32
  Speaker 1: It wasn't like mostly empty space with a tiny dot
• 19:34
  Speaker 1: which then exploded. Was filled with this hot, dense stuff
• 19:37
  Speaker 1: which then expanded and cooled rapidly. So the temperature is
• 19:41
  Speaker 1: dropping as space is expanding, So you should think the
• 19:44
  Speaker 1: Big Bang is sort of happening everywhere all at once,
• 19:47
  Speaker 1: not from a tiny little dot. And this is why
• 19:50
  Speaker 1: I worry about teaching my eight year old anything, because
• 19:52
  Speaker 1: I swear when I was in high school, I watched
• 19:55
  Speaker 1: a video where like started as a dot and it exploded,
• 19:58
  Speaker 1: and you just blew my mind that it wasn't that
• 20:02
  Speaker 1: and that matter was everywhere. And now I feel like,
• 20:04
  Speaker 1: how many other things that I learned in high school
• 20:06
  Speaker 1: are not the way we view things anymore. And anyway
• 20:09
  Speaker 1: you blew in my mind, let's move on. There's a
• 20:11
  Speaker 1: lot of misperception about that, and part of that is
• 20:13
  Speaker 1: because the whole idea of the Big Bang has evolved.
• 20:16
  Speaker 1: Now we think of Big Bang is sort of like
• 20:18
  Speaker 1: the inflationary epic. We have some of the sort of
• 20:20
  Speaker 1: like question mark, hot dense stuff which then expanded very
• 20:23
  Speaker 1: very rapidly via cosmic inflation. And for those of you
• 20:26
  Speaker 1: interested in more details on about exactly how that happened
• 20:29
  Speaker 1: what we do and don't know about that, check out
• 20:31
  Speaker 1: our episode called Did this Particle Create the Big Bang?
• 20:34
  Speaker 1: Which goes into detail about some theories about what might
• 20:37
  Speaker 1: have caused that. Anyway, you have this hot, dense question
• 20:39
  Speaker 1: mark stuff, and then it gets less hot and less
• 20:42
  Speaker 1: dense as things cool. Right now, we talk a lot
• 20:45
  Speaker 1: on the podcast about what space is, and we say
• 20:47
  Speaker 1: that space is filled with quantum fields. Right, You have
• 20:51
  Speaker 1: a unit of space that has quantum fields in it,
• 20:53
  Speaker 1: like a field for the electron and a field for
• 20:55
  Speaker 1: the cork, and of field for the photons, right, and
• 20:58
  Speaker 1: particles are just like apples in those fields. Now, you
• 21:02
  Speaker 1: go back to the very very early universe, everything was
• 21:04
  Speaker 1: so hot and so dense and so filled with energy
• 21:08
  Speaker 1: that it doesn't even really make sense to talk about
• 21:11
  Speaker 1: particles yet. It's like looking at the ocean and asking, like,
• 21:14
  Speaker 1: are there any drops in the ocean and you say, like, no,
• 21:16
  Speaker 1: it's just sort of like filled with water. In the
• 21:19
  Speaker 1: same way, these quantum fields were so energized because everything
• 21:22
  Speaker 1: was so hot and dense that the concept of a particle,
• 21:25
  Speaker 1: like a little localized packet of energy moving through the
• 21:28
  Speaker 1: universe doesn't really make sense, just like the wrong phase
• 21:32
  Speaker 1: of the universe. And it wasn't until a little bit
• 21:34
  Speaker 1: later after like ten to the minus thirty two seconds,
• 21:38
  Speaker 1: that things cooled down enough that you could say, here's
• 21:41
  Speaker 1: a particle. There's a particle. There's a particle. So that's
• 21:44
  Speaker 1: when like corks and gluons and photons and dark matter
• 21:48
  Speaker 1: all emerged from this early universe question mark stuff. So
• 21:52
  Speaker 1: the thing that triggered that then was cooling. So first
• 21:55
  Speaker 1: year have everything mixed up and they start separating when
• 21:58
  Speaker 1: it's cooling, and the cooling started just because time had
• 22:02
  Speaker 1: passed and things cool with time. Is that right? Or
• 22:05
  Speaker 1: did something trigger the movement from homogeneous whatever to like
• 22:11
  Speaker 1: specific things. It's the expansion that's the key. So space
• 22:15
  Speaker 1: is expanding, inflation is pulling space apart, and the same
• 22:19
  Speaker 1: process is happening right now. The universe is expanding. Currently
• 22:22
  Speaker 1: we call it dark energy, where space is making more space.
• 22:25
  Speaker 1: So between the atoms and your body, and between the
• 22:28
  Speaker 1: Earth and the Sun, and between our galaxy and other galaxies,
• 22:31
  Speaker 1: space is producing new chunks of space, so distances between
• 22:34
  Speaker 1: stuff is increasing. We don't understand why it's doing that
• 22:37
  Speaker 1: or how it's doing that. But in the very early
• 22:39
  Speaker 1: universe a very similar process happened, but much more dramatic
• 22:42
  Speaker 1: and much faster. And so this expansion then cools everything down.
• 22:46
  Speaker 1: So the overall arc of history of the universe is
• 22:50
  Speaker 1: start very hot and dense and then cool and expand
• 22:53
  Speaker 1: and become less dense and more dilute. And as that happens,
• 22:56
  Speaker 1: we sort of like move through different temperature regions, we
• 22:59
  Speaker 1: get differ and sort of effects, you know, the same
• 23:01
  Speaker 1: way like you have a gas and then a liquid
• 23:03
  Speaker 1: and a solid. We have different phases of matter. We
• 23:06
  Speaker 1: had different phases of sort of the physical laws of
• 23:09
  Speaker 1: the universe when it made sense to talk about the
• 23:11
  Speaker 1: universe in different ways. So only when things cooled down
• 23:14
  Speaker 1: enough could we even like talk about particles as phenomena
• 23:18
  Speaker 1: in quantum fields. So that went on for like ten
• 23:21
  Speaker 1: to the mine is twelve seconds, and then things kept cooling,
• 23:24
  Speaker 1: and the Higgs field is really weird field that interacts
• 23:28
  Speaker 1: with the particles and gives them mass. It cooled down
• 23:30
  Speaker 1: and sort of got stuck on a shelf, and we
• 23:32
  Speaker 1: talked about this in several episodes, how the Higgs field
• 23:34
  Speaker 1: is very weird because it doesn't relax down as much
• 23:37
  Speaker 1: as other fields, and that sort of stuck in a
• 23:39
  Speaker 1: high potential and it has a lot of energy stored
• 23:41
  Speaker 1: in it, and that's what gives a lot of particles mass.
• 23:44
  Speaker 1: We have a bunch of episodes on the Higgs boson
• 23:46
  Speaker 1: if you want to learn more details about that. So
• 23:48
  Speaker 1: here the particles now get mass. So you have the
• 23:50
  Speaker 1: quarks and the electrons. They used ton't have no mass,
• 23:53
  Speaker 1: now they do have mass. So the universe still has
• 23:56
  Speaker 1: no protons in it, but now it has like quarks
• 24:00
  Speaker 1: and electrons and gluons in this big hot suit called
• 24:03
  Speaker 1: cork gluon plasma. And we also have a whole episode
• 24:07
  Speaker 1: about what that is and how people make it at
• 24:09
  Speaker 1: a large change on collider to study the early universe.
• 24:12
  Speaker 1: So saying, you know, this happened at tend to the
• 24:14
  Speaker 1: negative thirty two seconds, and this other thing happened at
• 24:16
  Speaker 1: tend to the negative twelve seconds, Like, those are really
• 24:18
  Speaker 1: short time periods. Right to the negative something means that
• 24:22
  Speaker 1: many zeros after the decimal, right, So how do we
• 24:24
  Speaker 1: figure out down to that level of precision? Is that
• 24:27
  Speaker 1: too off course to be asking that question. No, it's
• 24:30
  Speaker 1: a great question. How well do we know these numbers?
• 24:33
  Speaker 1: We don't know them very well at all. All of
• 24:35
  Speaker 1: these come out of sort of our models for we
• 24:37
  Speaker 1: think happened, and of these huge question marks here we
• 24:40
  Speaker 1: could be off by, you know, big factors. So this
• 24:43
  Speaker 1: is sort of the current understanding, and so we should
• 24:45
  Speaker 1: put like big uncertainties on these numbers. For sure, it
• 24:48
  Speaker 1: couldn't have taken like a million years, because what happened
• 24:50
  Speaker 1: in the very early universe crystallized very quickly and it
• 24:54
  Speaker 1: has long term impacts on the rest of the universe
• 24:57
  Speaker 1: as we'll see. So we're pretty sure that this stuff
• 25:00
  Speaker 1: been very very quickly. That the specific numbers are a
• 25:03
  Speaker 1: little fuzzy, all right. So in like the blink of
• 25:05
  Speaker 1: an eye, we've got quarks but not yet protons exactly,
• 25:08
  Speaker 1: And so it's too hot for protons to form, Like
• 25:11
  Speaker 1: there's just too much energy because what is a proton?
• 25:14
  Speaker 1: You have three quarks, and they're bound together by the gluons.
• 25:17
  Speaker 1: But protons can get broken up, right, if you smash
• 25:20
  Speaker 1: them together, you put enough energy into your collider, you
• 25:22
  Speaker 1: can break them up. If you heat up the whole universe,
• 25:24
  Speaker 1: then protons sort of melt into their constituents, right, And
• 25:28
  Speaker 1: so what you need to do to make protons form
• 25:30
  Speaker 1: is you need the universe to cool down even further.
• 25:32
  Speaker 1: So then like ten to the minus six seconds, then
• 25:35
  Speaker 1: protons formed. The universe was now too cold for quarks
• 25:39
  Speaker 1: and gluons to just like fly around in this plasma,
• 25:42
  Speaker 1: and so that cooled down, and then you've got hadrons,
• 25:45
  Speaker 1: you've got protons, and you've got neutrons, and you have electrons,
• 25:48
  Speaker 1: and that's basically hydrogen. Right. Remember that protons are hydrogen.
• 25:53
  Speaker 1: Astronomers don't really care if there's an electron on it
• 25:56
  Speaker 1: or not. If there's a proton there, they call that hydrogen.
• 25:59
  Speaker 1: So that was the birth of hydrogen. Ten of the
• 26:02
  Speaker 1: minus six seconds into the universe. Hydrogen was born. So
• 26:06
  Speaker 1: does that mean that hydrogen is also the first element
• 26:09
  Speaker 1: that was ever made or just the most abundant that
• 26:11
  Speaker 1: was made at this point? I think both of those
• 26:13
  Speaker 1: things are true. Hydrogen was the first element made and
• 26:17
  Speaker 1: the most abundant, and in the next few seconds you'll
• 26:19
  Speaker 1: see that a little bit of other stuff was made
• 26:22
  Speaker 1: in this sort of like ending days of the Big Bang,
• 26:25
  Speaker 1: But basically it just formed huge amounts of hydrogen. That
• 26:28
  Speaker 1: also means that all the hydrogen in the universe is
• 26:31
  Speaker 1: super duper old. It's been around except for the first
• 26:34
  Speaker 1: ten to the minus six seconds of the universe. It's
• 26:36
  Speaker 1: been here. All hydrogen that's in the atmosphere or in
• 26:39
  Speaker 1: the sun or in the stars, it's as old as
• 26:41
  Speaker 1: the universe except for ten to the six seconds. So
• 26:44
  Speaker 1: we're all old souls. We are all old souls. So
• 26:49
  Speaker 1: that hydrogen has been hanging out for a long time,
• 26:51
  Speaker 1: and it's spent like three hundred and eighty thousand years
• 26:55
  Speaker 1: before it found its electrons, before the universe cooled even
• 26:58
  Speaker 1: further to make new trull hydrogen gas. So it's been
• 27:02
  Speaker 1: neutral hydrogen for a very, very very long time. But
• 27:04
  Speaker 1: it's been technically hydrogen since the very beginning. I guess
• 27:07
  Speaker 1: it took so long to get the electrons because you
• 27:09
  Speaker 1: needed just a whole lot more cooling before the electrons
• 27:13
  Speaker 1: came around. Yeah, things were still too hot, so electrons
• 27:15
  Speaker 1: had too much energy to get trapped by the protons.
• 27:19
  Speaker 1: So electrons and protons were flying around near each other,
• 27:22
  Speaker 1: but they were just moving too fast for the bonds
• 27:24
  Speaker 1: to form for them to pull into each other and
• 27:27
  Speaker 1: form hydrogen. So you just to wait for the universe
• 27:28
  Speaker 1: to keep cooling until like gelled into neutral hydrogen. Well,
• 27:32
  Speaker 1: speaking of cooling, the audience is going to have to
• 27:35
  Speaker 1: cool their heels for a little while because it's time
• 27:37
  Speaker 1: for a break. Alright, we're back. So we talked about
• 27:52
  Speaker 1: hydrogen already, which is the most abundant and the earliest
• 27:55
  Speaker 1: formed elements. So who takes the number two? But so
• 28:00
  Speaker 1: number two, no surprise is helium, right, Helium is element
• 28:05
  Speaker 1: number two. It's made out of two protons in the
• 28:08
  Speaker 1: nucleus with two electrons going around it, and there's usually
• 28:11
  Speaker 1: also some number of neutrons in there. And helium is
• 28:15
  Speaker 1: seven point one percent of the universe by atoms. So
• 28:19
  Speaker 1: if you just like lined up all the atoms in
• 28:21
  Speaker 1: the universe and counted them, helium would be about seven
• 28:24
  Speaker 1: point one percent. Remember that hydrogen is so already. In
• 28:29
  Speaker 1: hydrogen and helium together you have ninety hind point one
• 28:33
  Speaker 1: percent of all the atoms in the universe. Everything else
• 28:36
  Speaker 1: is now less than one percent of the stuff in
• 28:39
  Speaker 1: the universe. Wow, Is it possible that there's some universe
• 28:43
  Speaker 1: out there where there's more helium than hydrogen and everybody's
• 28:46
  Speaker 1: got a squeaky voice? Or you just have to always
• 28:48
  Speaker 1: have hydrogen first. I love thinking about that universe, and
• 28:54
  Speaker 1: I imagine for a moment maybe I would try to
• 28:56
  Speaker 1: do an Alvin Chipmunk voice to answer your question, and
• 28:58
  Speaker 1: then I realized I just couldn't do it. But it's
• 29:00
  Speaker 1: a good question, because you know, where did that helium
• 29:03
  Speaker 1: come from. It came from that primordial hydrogen in the
• 29:06
  Speaker 1: sort of ending days of the Big Bang, and its
• 29:08
  Speaker 1: immediate aftermath form that helium, and so we'll learn about
• 29:11
  Speaker 1: exactly how that happened. But it's hard to imagine converting
• 29:14
  Speaker 1: a majority of the hydrogen into helium in this early
• 29:17
  Speaker 1: universe fusion process, But it might be possible. You have
• 29:20
  Speaker 1: to tweak some of the laws of physics to make
• 29:22
  Speaker 1: that happen. A worthwhile endeavor, no doubt. And you know
• 29:25
  Speaker 1: what's funny about these elements is that astrophysicists think about
• 29:30
  Speaker 1: hydrogen and helium is basically most of the universe, and
• 29:32
  Speaker 1: everything else is the leftovers, which they call metals. You know, chemists,
• 29:37
  Speaker 1: when they talk about metals, they talk very specifically about
• 29:39
  Speaker 1: part of the periodic table that has you know, high
• 29:42
  Speaker 1: conductivity and is shiny. For example, the kind of things
• 29:45
  Speaker 1: that you and I think of as a metal. We
• 29:47
  Speaker 1: don't think like oxygen as a metal. We don't think
• 29:49
  Speaker 1: about the cells is like breathing metal gas. But to astronomers,
• 29:54
  Speaker 1: it's hydrogen, helium and metals. Why would they do that?
• 29:58
  Speaker 1: Is it just because it's a very different process, and
• 30:01
  Speaker 1: so they want a category. Is it as something else?
• 30:03
  Speaker 1: Ye As we'll see basically everything else is made after
• 30:06
  Speaker 1: the Big Bang inside stars, and they like to think
• 30:08
  Speaker 1: of stars as creating medals, and so for them, it's
• 30:12
  Speaker 1: just a totally different categorization. I think. Also it's just
• 30:15
  Speaker 1: because hydrogen helium are the big players, so they want
• 30:18
  Speaker 1: like a name for everything else, and like we often
• 30:21
  Speaker 1: do in physics, they took a name which exists and
• 30:23
  Speaker 1: means something else, and they gave it a new, confusing definition.
• 30:26
  Speaker 1: Find that very frustrating about, y'all. So let's continue with
• 30:29
  Speaker 1: the history of the universe to understand how other stuff
• 30:32
  Speaker 1: was made. So we're like ten of the minus six
• 30:34
  Speaker 1: seconds into the universe. We have protons, we have electrons,
• 30:38
  Speaker 1: we have neutrons. But everything is flying around really really hot,
• 30:42
  Speaker 1: and we also have a lot of anti matter. And
• 30:45
  Speaker 1: we think that in the very early universe we created matter,
• 30:48
  Speaker 1: but we also created antimatter, so that means anti protons
• 30:52
  Speaker 1: and anti electrons. And we imagine that the Big Bang
• 30:55
  Speaker 1: created this stuff in equal numbers. That when it's like
• 30:59
  Speaker 1: pre matter energy cooled down to create particles, it created
• 31:02
  Speaker 1: all the particles basically in equal numbers, and so we
• 31:06
  Speaker 1: think that antimatter was created at the same rate as matter.
• 31:09
  Speaker 1: So then you had like big flashes of life. Because
• 31:12
  Speaker 1: what happens when matter hits antimatter is it annihilates. You
• 31:16
  Speaker 1: have an electron hit and anti electron also called a positron,
• 31:20
  Speaker 1: you get a photon, and so huge amounts of matter
• 31:23
  Speaker 1: and antimatter disappeared very quickly, and a lot of photons
• 31:28
  Speaker 1: were made, and so after about ten seconds of living
• 31:31
  Speaker 1: it out in a crazy particle party, the universe then
• 31:34
  Speaker 1: became dominated by photons from matter antimatter annihilation. But if
• 31:39
  Speaker 1: you're wearing the star screen that you and I started
• 31:41
  Speaker 1: selling a couple of weeks ago. You'll be okay. But
• 31:44
  Speaker 1: so I'm trying to like match up the vision in
• 31:46
  Speaker 1: my head from when I was in high school. So
• 31:47
  Speaker 1: in that case, the light in like the video that
• 31:50
  Speaker 1: I'm remember, it was all in one center location and
• 31:52
  Speaker 1: then spread out. But here, like the photons being made,
• 31:56
  Speaker 1: it would be like everything would be lighting up at once, right,
• 31:58
  Speaker 1: it wouldn't be in one central local aation. It's all
• 32:00
  Speaker 1: over the place. That's right. Because we think the Big
• 32:02
  Speaker 1: Bang happened everywhere. It also means there's no center to
• 32:06
  Speaker 1: the universe, not like this stuff all happens somewhere and
• 32:09
  Speaker 1: it's flying out from there. It happened everywhere. It happened here.
• 32:13
  Speaker 1: You are right now at the place where the Big
• 32:15
  Speaker 1: Bang happened. Literally right. It happened everywhere, all at once,
• 32:19
  Speaker 1: And so the whole universe was filled with matter and antimatter,
• 32:22
  Speaker 1: which then annihilated very rapidly. And they know the universe
• 32:25
  Speaker 1: with the enormous amounts of high energy photons flying around.
• 32:28
  Speaker 1: So we call this the radiation dominated epoch of the universe,
• 32:32
  Speaker 1: when most of the energy was in photons and not
• 32:35
  Speaker 1: in like things we call matter, but there were small
• 32:37
  Speaker 1: amounts of matter that were left over for reasons we
• 32:40
  Speaker 1: still don't understand. There are mysterious processes that either created
• 32:43
  Speaker 1: more matter than antimatter or preferably converted some of the
• 32:46
  Speaker 1: antimatter to matter. So it's a little bit of an imbalance,
• 32:49
  Speaker 1: and some matter was left over. So you end up
• 32:52
  Speaker 1: with a universe with lots of photons and a little
• 32:54
  Speaker 1: bit of protons, electrons and neutrons left over all, right,
• 32:58
  Speaker 1: So then how do we get from all of those
• 33:00
  Speaker 1: photons to having mercury? I love this phrase murdering. It
• 33:09
  Speaker 1: makes it sound like a legal thing, like the protons
• 33:11
  Speaker 1: and the lawyers got together and they're like, let's talk
• 33:13
  Speaker 1: about the future of these particles. Well, I said, I
• 33:16
  Speaker 1: said mercury, but I prefer what you said. That what
• 33:20
  Speaker 1: you said is way more interesting, So we're going with that.
• 33:22
  Speaker 1: That's what I said. I made up a great new work.
• 33:24
  Speaker 1: You made up particle murdering. And so what happened next
• 33:27
  Speaker 1: is that you have a universe basically filled with hydrogen,
• 33:30
  Speaker 1: and this hydrogen also with not just pure proton plust electron,
• 33:34
  Speaker 1: A lot of them had a neutron tagging along. So
• 33:36
  Speaker 1: we call this deuterium. Where do means like too? So
• 33:40
  Speaker 1: you have two nucleons in their proton and a neutron
• 33:43
  Speaker 1: surrounded by an electron, and the universe was cool enough
• 33:47
  Speaker 1: to form that, but still hot enough for fusion, right,
• 33:50
  Speaker 1: So fusion is when you take two pieces of hydrogen,
• 33:53
  Speaker 1: two protons essentially, even though they repel each other electrically,
• 33:57
  Speaker 1: because they're both positively charged, you squeeze them together. Then
• 34:01
  Speaker 1: you can form helium. And so this happens in the
• 34:04
  Speaker 1: heart of stars all the time, and we're trying to
• 34:06
  Speaker 1: make it happen here on Earth in fusion reactors that
• 34:09
  Speaker 1: can release energy, but it requires very high temperatures and
• 34:12
  Speaker 1: very high densities. But for a few minutes after the
• 34:16
  Speaker 1: Big Bang of these conditions existed. So three minutes after
• 34:19
  Speaker 1: this unknown state expanded very very rapidly, the conditions were
• 34:23
  Speaker 1: perfect for hydrogen fusion into helium, and that's where most
• 34:28
  Speaker 1: of the helium in the universe was made after three minutes.
• 34:32
  Speaker 1: So this is my monthly moment of existential dread. All
• 34:35
  Speaker 1: of this talk about like heating and cooling, does that
• 34:38
  Speaker 1: mean that, like, if things had cooled down much faster,
• 34:42
  Speaker 1: none of this stuff would have happened, and like there's
• 34:45
  Speaker 1: you know we're talking about you know, ten to the
• 34:47
  Speaker 1: negative thirty two seconds, like these tiny little time scales.
• 34:50
  Speaker 1: If the timing had been a little bit different, whit
• 34:53
  Speaker 1: we have never gotten the photons to join together or whatever. Well,
• 34:57
  Speaker 1: the things had happened much faster than we wouldn't have
• 34:59
  Speaker 1: had as much time to make helium, so we'd have
• 35:02
  Speaker 1: more hydrogen in the universe. But hydrogen is sort of
• 35:04
  Speaker 1: the basic most stable thing, is sort of the inevitable endpoint.
• 35:08
  Speaker 1: If you take the universe and you cool it down,
• 35:10
  Speaker 1: you're gonna end up with hydrogen because it's got to
• 35:12
  Speaker 1: fall into up corks and down corks and electrons, and
• 35:15
  Speaker 1: as the universe cools, those things are going to form
• 35:17
  Speaker 1: stable objects. But it does determine how much helium you get.
• 35:21
  Speaker 1: So if you had like less time in that hot
• 35:23
  Speaker 1: phase when it was perfect to make helium, you get
• 35:26
  Speaker 1: less helium. Also, the density of the universe controls like
• 35:29
  Speaker 1: how much helium you get, and also how much lithium
• 35:31
  Speaker 1: you get. We'll talk about that in a moment. But
• 35:34
  Speaker 1: in this early phase you also sometimes we're able to
• 35:37
  Speaker 1: few things together to get lithium right, to get the
• 35:40
  Speaker 1: next element. But the ratio of hydrogen and helium and
• 35:43
  Speaker 1: lithium that you get is very very sensitive to the
• 35:46
  Speaker 1: temperature and to the cork density. So by understanding like
• 35:49
  Speaker 1: how much helium and hydrogen and lithium was made in
• 35:52
  Speaker 1: the early universe, we can tell what the cork density
• 35:55
  Speaker 1: was before that. Right, we know, for example, if you
• 35:58
  Speaker 1: had higher cork density, you would have gotten a different distribution.
• 36:01
  Speaker 1: You would have gotten more helium and more lithium. He
• 36:03
  Speaker 1: had less. Lower cork density, you would have gotten less
• 36:06
  Speaker 1: helium and less lithium. So what that means is that
• 36:08
  Speaker 1: we can account for the corks. We can say, look
• 36:10
  Speaker 1: out into the universe and we see the ratio hydrogen
• 36:13
  Speaker 1: and helium and lithium in the early universe. That tells
• 36:16
  Speaker 1: us about the cork density very early on. And that's
• 36:19
  Speaker 1: how we know that dark matter is not made of quarks,
• 36:22
  Speaker 1: because we can account for all those corks. We say,
• 36:25
  Speaker 1: we know how many corks were made very very early on.
• 36:28
  Speaker 1: Those all ended up in hydrogen and helium and lithium. Therefore,
• 36:31
  Speaker 1: the dark matter that's out there can't be made out
• 36:34
  Speaker 1: of corks. It's an important part of the argument for
• 36:36
  Speaker 1: why we think dark matter is not made of quarks
• 36:39
  Speaker 1: and not atomic matter at all. We are very clever.
• 36:42
  Speaker 1: Apes It's really incredible, And you know the folks who
• 36:45
  Speaker 1: think about, well, maybe dark matter is this other thing,
• 36:48
  Speaker 1: or maybe dark matter is a misunderstanding of gravity. This
• 36:51
  Speaker 1: is an important argument or why dark matter is matter
• 36:54
  Speaker 1: and why it's not just like dark heavy rocks floating
• 36:57
  Speaker 1: out in space that we haven't observed yet. So it's
• 37:00
  Speaker 1: really interesting how much you learn about the universe just
• 37:02
  Speaker 1: by understanding, like where these elements were crystallized and how
• 37:06
  Speaker 1: that process happened. That's awesome. We've talked about how you
• 37:08
  Speaker 1: make helium. Are there other ways to make helium or
• 37:12
  Speaker 1: did all of it come from this moment? So helium
• 37:14
  Speaker 1: is produced in the early universe, in the Big Bang,
• 37:17
  Speaker 1: but also much later right like our sun is a
• 37:20
  Speaker 1: helium factory because this process we talked about where hydrogen
• 37:24
  Speaker 1: comes together to make helium. That's exactly what's happening inside
• 37:27
  Speaker 1: our star. That's why it's like hot right now outside
• 37:30
  Speaker 1: because the energy from hydrogen burning inside the star is
• 37:35
  Speaker 1: producing helium. You have this complicated multi step process. We
• 37:38
  Speaker 1: actually need like two hydrogen nuclei to come together to
• 37:41
  Speaker 1: make deuterium. So you have two protons come together and
• 37:44
  Speaker 1: one of them actually converts into a neutron, which then
• 37:47
  Speaker 1: becomes an element of deuterium. You have it like another
• 37:51
  Speaker 1: hydrogen comes in and you make helium three, and then
• 37:53
  Speaker 1: those helium three merged together and you end up with
• 37:56
  Speaker 1: helium four. So it's a complicated, multi step process. But
• 37:59
  Speaker 1: this is what we call hydrogen burning, and it produces
• 38:02
  Speaker 1: most of the energy in the cores of most of
• 38:04
  Speaker 1: the stars out there. So when you look out in
• 38:06
  Speaker 1: the night sky and you see all that twinkling, mostly
• 38:09
  Speaker 1: you're observing hydrogen being turned into helium. Is that fusion
• 38:13
  Speaker 1: or fusion slightly different than what you just described. That
• 38:16
  Speaker 1: is exactly fusion that powers the stars, because you know,
• 38:19
  Speaker 1: there's a long gap here. We're talking about helium made
• 38:21
  Speaker 1: primordially during the Big Bang, the first three minutes of
• 38:24
  Speaker 1: the universe, but there were hundreds of millions of years
• 38:28
  Speaker 1: before the universe got to a place where it recreated
• 38:31
  Speaker 1: those conditions in the hearts of stars to make more helium,
• 38:34
  Speaker 1: because the universe was just vast clouds of hydrogen for
• 38:38
  Speaker 1: a long long time. We call these the dark ages
• 38:40
  Speaker 1: of the universe. Before gravity pulled those clouds together and
• 38:44
  Speaker 1: created the conditions for stars, so we could fuse this
• 38:47
  Speaker 1: hydrogen together to make more helium. So the universe have
• 38:50
  Speaker 1: been working on that be fourteen billion years or so,
• 38:52
  Speaker 1: and it still hasn't really changed the balance. You know,
• 38:55
  Speaker 1: most of the stuff out there is still just hydrogen. Wow,
• 38:58
  Speaker 1: helium doesn't usually go back to hydrogen, right, so you
• 39:01
  Speaker 1: still end up with that balance despite constantly turning hydrogen
• 39:04
  Speaker 1: into helium exactly. We've been working on it for a
• 39:06
  Speaker 1: long time, but it's a long process, and there's so
• 39:08
  Speaker 1: much hydrogen out there that it's going to take a
• 39:10
  Speaker 1: long time before we burn through it. We have an
• 39:12
  Speaker 1: episode about like how many generations of stars there will be,
• 39:17
  Speaker 1: and we think the universe has like trillions of years
• 39:19
  Speaker 1: of fuel potentially to burn stars. All Right, so I
• 39:22
  Speaker 1: can tell my kids about that because I won't scare
• 39:24
  Speaker 1: them to all Right, we've gotten hydrogen and helium, which
• 39:27
  Speaker 1: were the most common guesses from the audience. Let's take
• 39:30
  Speaker 1: a break, and then let's hear about who the runner
• 39:32
  Speaker 1: up is. Who's in third place? Alright, so the universe
• 39:48
  Speaker 1: is mostly hydrogen. Second place way far behind is helium.
• 39:53
  Speaker 1: Who's coming in third. You might think by extrapolation that
• 39:56
  Speaker 1: number three would be the element with three protons in it,
• 39:59
  Speaker 1: that you could like take helium and hydrogen infuse them
• 40:02
  Speaker 1: together to make lithium, which is three protons, But actually
• 40:05
  Speaker 1: lithium is very very rare in the universe. There only
• 40:08
  Speaker 1: trace amounts of lithium. Number three is actually oxygen. Oxygen
• 40:13
  Speaker 1: is the third most common element in the universe. So
• 40:16
  Speaker 1: we'll get to that in a minute, but let's talk
• 40:17
  Speaker 1: about lithium and like why it's so weird. It turns
• 40:20
  Speaker 1: out that lithium is really unstable, and so they are
• 40:24
  Speaker 1: produced in nuclear fusion, but only very briefly because they
• 40:27
  Speaker 1: basically fall apart very rapidly, So unlike helium or other stuff,
• 40:32
  Speaker 1: when you make lithium, it doesn't last very long. It
• 40:34
  Speaker 1: just sort of like falls back apart, and oxygen is
• 40:37
  Speaker 1: more stable. Oxygen is much more stable. So you might
• 40:40
  Speaker 1: be wondering, like, what makes something stable or not stable?
• 40:43
  Speaker 1: What were we talking about here? Remember that we're talking
• 40:45
  Speaker 1: about gluing protons and neutrons together, which is complicated. It's
• 40:49
  Speaker 1: well beyond the like chemistry of pluses and minuses. Everything
• 40:54
  Speaker 1: inside the nucleus is either positively charged or neutral. So
• 40:57
  Speaker 1: what's sticking them together anyway? Why can you stick to
• 41:00
  Speaker 1: protons together to make helium or even heavier stuff. The
• 41:03
  Speaker 1: answer is the strong nuclear force. The gluons that are
• 41:06
  Speaker 1: inside these protons and neutrons can also talk to each other.
• 41:10
  Speaker 1: So when you get two protons close enough to each other,
• 41:12
  Speaker 1: and the gluons that are inside them can sort of
• 41:14
  Speaker 1: grab onto each other and overcome their electrostatic repulsion. And
• 41:19
  Speaker 1: that's very complicated, and it's good in some configurations but
• 41:22
  Speaker 1: not in others, which is what makes some elements stable
• 41:25
  Speaker 1: and other elements not. And so you tend to form
• 41:28
  Speaker 1: these things in shells. Just like we have shells of
• 41:31
  Speaker 1: electrons inside the nucleus, we think there are shells of
• 41:34
  Speaker 1: protons and neutrons that arrange themselves in various configurations. Some
• 41:38
  Speaker 1: of those configurations are like very nicely packed, like a
• 41:41
  Speaker 1: roman arch that's stable, and other configurations are very unstable.
• 41:45
  Speaker 1: And lithium turns out to be like a very unstable configuration.
• 41:49
  Speaker 1: So this is another thing that I feel like I
• 41:50
  Speaker 1: don't remember learning when I was in high school or college.
• 41:53
  Speaker 1: Is this another like new thing? Or like was I sick?
• 41:55
  Speaker 1: On the wrong day. I don't know how often you
• 41:58
  Speaker 1: paid attention in college. This is something we've been working
• 42:01
  Speaker 1: on for a few decades. Understanding, like the nuclear shell model,
• 42:05
  Speaker 1: probably not very often taught in high school, but the
• 42:07
  Speaker 1: cold concept that some of these things are more stable
• 42:09
  Speaker 1: than others should be familiar. Yeah, okay, that's familiar. Okay,
• 42:12
  Speaker 1: So sets of three are just not very stable, and
• 42:16
  Speaker 1: that's why we don't have lithium around for a long time. Yeah,
• 42:18
  Speaker 1: lithium in general is just not very stable. Other elements
• 42:21
  Speaker 1: are much more stable. Like you get up to carbon.
• 42:24
  Speaker 1: Carbon is stable, and that has six right, And so
• 42:27
  Speaker 1: it's not as simple as like sets of three. Some
• 42:29
  Speaker 1: of these things the way they are arranged, are stable
• 42:31
  Speaker 1: and some of them are not. And it's not easy
• 42:33
  Speaker 1: to calculate either. It's not like you can just sit
• 42:35
  Speaker 1: down with a couple of equations and figure this stuff out,
• 42:37
  Speaker 1: because the strong force is very strong and very nasty
• 42:40
  Speaker 1: and very hard to do any calculations with. But because
• 42:42
  Speaker 1: lithium and the next element, beryllium are so unstable, basically
• 42:47
  Speaker 1: nothing else was made in the Big Bang. Big Bang
• 42:49
  Speaker 1: is like massive amounts of hydrogen, a little bit of helium,
• 42:53
  Speaker 1: tiny tiny bits of lithium and nothing else because lithium
• 42:57
  Speaker 1: is sort of like a barrier. You can't it past
• 43:00
  Speaker 1: lithium in the early universe, and so you couldn't really
• 43:03
  Speaker 1: make anything else. That's why the Big Bang didn't make
• 43:06
  Speaker 1: like uranium or plutonium, because one of the stepping stones
• 43:10
  Speaker 1: to get there was too unstable to last, and so
• 43:13
  Speaker 1: lithium is not a metal though, because it didn't stick around.
• 43:17
  Speaker 1: Astronomers would call lithium a metal for sure, because there
• 43:20
  Speaker 1: are some amounts of it in the universe, but it's very,
• 43:22
  Speaker 1: very rare. The same is true for berrillium, which is
• 43:25
  Speaker 1: the next element. It exists in the universe, but it
• 43:28
  Speaker 1: wasn't made in the Big Bang. It's too heavy, and
• 43:31
  Speaker 1: some of it is made inside stars. Right. If refused
• 43:35
  Speaker 1: to helium atoms together, sometimes you get burrillium, but a
• 43:38
  Speaker 1: lot of it is also very unstable, and so some
• 43:41
  Speaker 1: isotopes of it don't last very long. A lot of
• 43:43
  Speaker 1: it falls apart. Actually, most of the billium in the
• 43:47
  Speaker 1: universe was not made inside stars at all. Most of
• 43:50
  Speaker 1: the brillium in the universe was made by taking oxygen,
• 43:54
  Speaker 1: which is everywhere and exists between stars, and then hitting
• 43:58
  Speaker 1: it with a cosmic ray. So you have, for example,
• 44:01
  Speaker 1: stars are giving out their stellar wind, which is like
• 44:04
  Speaker 1: streams of particles, protons, electrons, all sorts of stuff. So
• 44:07
  Speaker 1: we call these things cosmic rays. Just high energy particles
• 44:10
  Speaker 1: flying through the universe. If one of them hits an
• 44:12
  Speaker 1: oxygen atom, it can knock off some of the protons
• 44:16
  Speaker 1: inside the oxygen atom. So this is like fission, right,
• 44:19
  Speaker 1: not fusion. You're taking lighter elements and using them to
• 44:22
  Speaker 1: build heavier stuff. This is taking heavier elements and break
• 44:24
  Speaker 1: them apart. It's like what happens in fission reactors with uranium.
• 44:28
  Speaker 1: You break uranium down into lighter elements. In the interstellar medium,
• 44:32
  Speaker 1: we think they're vast clouds of oxygen. Sometimes a proton
• 44:35
  Speaker 1: hits one and makes beryllium, so burrillium is actually made
• 44:38
  Speaker 1: by cosmic rays between stars. When oxygen gets hit by
• 44:42
  Speaker 1: a cosmic ray, does it always make billium or does
• 44:44
  Speaker 1: it sometimes make other things depending on like how it
• 44:47
  Speaker 1: got hit. It doesn't always make brilliums. Sometimes it just
• 44:49
  Speaker 1: bounce off each other. But sometimes a high enough energy
• 44:52
  Speaker 1: proton just the right way will crack open the oxygen
• 44:55
  Speaker 1: and break it up into pieces. And that's mostly how
• 44:58
  Speaker 1: berrillium was made in the universe. But it'll like never
• 45:00
  Speaker 1: break oxygen into like three heliums for example. You can
• 45:04
  Speaker 1: do that. Also, Yeah, you can get lots of different
• 45:06
  Speaker 1: stuff when you smash these particles together. So you mentioned
• 45:09
  Speaker 1: that carbon is the next thing that we have the
• 45:11
  Speaker 1: most of Where is the carbon coming from? So carbon
• 45:15
  Speaker 1: was not made in the very early universe because it's
• 45:18
  Speaker 1: kind of tricky. To make carbon requires this like three
• 45:21
  Speaker 1: step dance. Carbon requires six protons, right, And you can't
• 45:24
  Speaker 1: just fuse lithium together because lithium is unstable. You can't
• 45:27
  Speaker 1: just like take two lithium atoms and stick them together
• 45:30
  Speaker 1: because it just isn't enough lithium around. So what you
• 45:32
  Speaker 1: need to do instead of fusing two lithiums together is
• 45:35
  Speaker 1: you need to fuse three heliums together. So you need
• 45:38
  Speaker 1: six protons, two from each of three different helium atoms. Now,
• 45:43
  Speaker 1: in the very early universe we made helium and that
• 45:46
  Speaker 1: helium bounce off each other. But it's very hard to
• 45:48
  Speaker 1: get like three heliums together. It's much more complicated than
• 45:52
  Speaker 1: getting two heliums together. And so this is a complicated process.
• 45:56
  Speaker 1: We have two heliums come together to make beryllium, which
• 45:59
  Speaker 1: is also really unstable. But before the brillium falls apart,
• 46:02
  Speaker 1: you need that third helium to come in to swoop
• 46:05
  Speaker 1: in and turn it into carbon. So like if you
• 46:07
  Speaker 1: get that third one in place just in time, this
• 46:10
  Speaker 1: is called the three alpha process, then you can make
• 46:13
  Speaker 1: it over the unstable skipping stone of burrillium and get
• 46:17
  Speaker 1: the carbon. And where is this happening. Is this in
• 46:19
  Speaker 1: the sun or is this happening out where you get
• 46:22
  Speaker 1: the oxygen becoming brillium. So this happens inside of stars,
• 46:25
  Speaker 1: but it's not easy for it to happen right. In
• 46:28
  Speaker 1: order for this to happen, the star has to be
• 46:29
  Speaker 1: like really big and really hot so we can burn helium.
• 46:32
  Speaker 1: And it's not just that it has to be hot,
• 46:34
  Speaker 1: has to be dense, so you have like enough helium
• 46:36
  Speaker 1: around so that one of these helium atoms hits the
• 46:39
  Speaker 1: brillium before it breaks apart. But this is really fascinating
• 46:42
  Speaker 1: process because a lot of stars are not hot enough
• 46:45
  Speaker 1: to burn helium for most of their lives, like our star.
• 46:48
  Speaker 1: For example, Helium when you produce it in our star
• 46:51
  Speaker 1: just falls to the center of the star and accumulates
• 46:54
  Speaker 1: at the core. They're kind of inert for a long
• 46:55
  Speaker 1: long time. Our star is not hot enough to burn
• 46:58
  Speaker 1: the helium, but it will be for a very brief
• 47:01
  Speaker 1: moment near the end of its life, when enough of
• 47:04
  Speaker 1: that helium accumulates, so it's enough gravitational pressure, all of
• 47:08
  Speaker 1: a sudden, it's going to cross this threshold and it's
• 47:10
  Speaker 1: going to burn all of that helium really quickly into carbon.
• 47:14
  Speaker 1: It's called a helium flash, and for a few seconds,
• 47:17
  Speaker 1: the Sun will produce a hundred billion times as much
• 47:22
  Speaker 1: energy as it normally does. So that means that the
• 47:26
  Speaker 1: carbon on Earth didn't come from our Sun because our
• 47:29
  Speaker 1: son couldn't make it yet, So the carbon on Earth
• 47:32
  Speaker 1: came from other suns, yes, exactly, because we're like three
• 47:36
  Speaker 1: generations of suns in the universe. So most of the
• 47:39
  Speaker 1: carbon that we have here on Earth was formed during
• 47:41
  Speaker 1: one of these helium burning events inside another star, which
• 47:45
  Speaker 1: burned for billions of years and then died and exploded
• 47:49
  Speaker 1: and spread out its seeds into the universe. The universe
• 47:51
  Speaker 1: started out as almost all hydrogen in a little bit
• 47:54
  Speaker 1: of helium, so those first few stars in their solar
• 47:56
  Speaker 1: systems were almost all just hydrogen, but the next generation
• 48:00
  Speaker 1: were more metallic, as astronomers say, and the next generation
• 48:03
  Speaker 1: are even more metallic. So our Solar System is part
• 48:05
  Speaker 1: of the third generation, we think, And so we have
• 48:07
  Speaker 1: lots of leftover bits that were produced inside other stars.
• 48:11
  Speaker 1: So this is what you were talking about earlier. We
• 48:13
  Speaker 1: are all star stuff. The carbon that's inside our body
• 48:16
  Speaker 1: was made by fusing helium inside other stars. But so
• 48:20
  Speaker 1: then like the Moon doesn't have like any carbon, right,
• 48:24
  Speaker 1: so it's kind of the carbon sort of the star
• 48:26
  Speaker 1: explodes and the carbon goes out there, and then it's
• 48:28
  Speaker 1: sort of like actually distributed throughout the universe. Is that
• 48:32
  Speaker 1: fair to say, Yeah, exactly, because the Earth doesn't have
• 48:35
  Speaker 1: the same distribution of stuff as the whole universe does. Right,
• 48:38
  Speaker 1: Like when the Solar System formed, most of the hydrogen
• 48:41
  Speaker 1: that went into forming the Solar System went to Jupiter
• 48:44
  Speaker 1: and the Sun. We got very very little hydrogen. We
• 48:47
  Speaker 1: got a lot of the heavier stuff because we had
• 48:49
  Speaker 1: like a heavy, rocky seed that gathered together some of
• 48:51
  Speaker 1: the heavier stuff. So the Earth is not a representative
• 48:54
  Speaker 1: sample of the universe at all, but the Solar System
• 48:57
  Speaker 1: as a whole is more representative. Like I say, usually
• 49:00
  Speaker 1: of talking to you gives me like existential dread. But
• 49:02
  Speaker 1: I'm feeling pretty uplifted right now that all of these
• 49:04
  Speaker 1: different things that we've talked about have all so far
• 49:06
  Speaker 1: gone in the direction of creating the Earth. It seems
• 49:09
  Speaker 1: like a pretty low probability thing, all right. So moving
• 49:12
  Speaker 1: past carbon, tell me about some of the heavier stuff.
• 49:14
  Speaker 1: And so from there we need heavier, hotter stars that
• 49:17
  Speaker 1: are capable of burning helium and then capable of like
• 49:21
  Speaker 1: burning carbon. So if you have the right conditions, if
• 49:24
  Speaker 1: you have enough pressure and enough temperature and anough density,
• 49:27
  Speaker 1: you can fuse carbon together. This is called carbon burning.
• 49:30
  Speaker 1: And then it's just stepping your way up the periodic table.
• 49:33
  Speaker 1: You can get all the way up to iron. You
• 49:36
  Speaker 1: can fuse things up to iron, and the process releases energy.
• 49:39
  Speaker 1: And we talk about fusion. Were like smush two nuclear together.
• 49:43
  Speaker 1: We got a heavier nucleus plus energy. That's why stars
• 49:46
  Speaker 1: glow and continue to burn because the energy that's produced
• 49:49
  Speaker 1: from the fusion keeps the fusion going. But after iron,
• 49:53
  Speaker 1: when you try to fuse iron together with other stuff,
• 49:55
  Speaker 1: it eats energy. Like the weird nuclear structure that's keeping
• 49:59
  Speaker 1: these things together there, It starts to need energy to
• 50:02
  Speaker 1: form these other heavier elements. So you want to make
• 50:04
  Speaker 1: like lead and uranium inside your star. You can do it,
• 50:07
  Speaker 1: but it cools the star down, so it contributes to
• 50:10
  Speaker 1: killing the star rather than keeping it burning. And so
• 50:14
  Speaker 1: inside the star you can make like things up to
• 50:16
  Speaker 1: about iron with fusion, But afterwards the process slows down
• 50:20
  Speaker 1: really rapidly because it's a cooling process instead of a
• 50:23
  Speaker 1: heating process. But you need to get super hot to
• 50:26
  Speaker 1: make iron, right, so you get super hot, you start
• 50:28
  Speaker 1: making iron, and then that cools you down exactly, and
• 50:31
  Speaker 1: only the biggest, most massive stars can even make iron.
• 50:34
  Speaker 1: Like our sun will never make iron. It'll fuse helium
• 50:37
  Speaker 1: at its core and it will make some carbon and
• 50:39
  Speaker 1: its last few gasps, but it will never make anything
• 50:41
  Speaker 1: heavier than that. To get iron, you need like much
• 50:44
  Speaker 1: more massive stars. And then to get heavier than iron,
• 50:47
  Speaker 1: you might wonder like, well, where does that come from?
• 50:49
  Speaker 1: How is that possible? If you can't use fusion with
• 50:51
  Speaker 1: a few other processes to make that stuff. Like one
• 50:54
  Speaker 1: thing you can do is called neutron capture. So you
• 50:57
  Speaker 1: have some heavy thing floating around a star, You're all
• 51:00
  Speaker 1: a bunch of neutrons floating around. Sometimes instead of like
• 51:02
  Speaker 1: actual fusion, where you add protons to an element, you
• 51:05
  Speaker 1: can add a neutron. Let's take for example, gold which
• 51:08
  Speaker 1: has waited one If it absorbs a neutron, it's still gold,
• 51:12
  Speaker 1: but now it's and gold is unstable and tends to
• 51:17
  Speaker 1: baita decay, so that neutron turns into a proton, and
• 51:20
  Speaker 1: now it's mercury. And so the gold is taken like
• 51:23
  Speaker 1: a two step dance of absorbing a neutron flipping it
• 51:26
  Speaker 1: into a proton, and now it's taken one step up
• 51:29
  Speaker 1: the periodic table. Wow, you go from something you really
• 51:32
  Speaker 1: want to something you really don't. Hey, no judgment here.
• 51:35
  Speaker 1: You know some people like mercury not in their pastries.
• 51:38
  Speaker 1: You know, I don't see fancy mercury flakes on pastries
• 51:41
  Speaker 1: as much as I see fancy gold foil. That's true. Yeah,
• 51:44
  Speaker 1: I don't want any mercury flakes in my liquor either,
• 51:47
  Speaker 1: or my my shampoo. Let's keep it out of our
• 51:49
  Speaker 1: stuff exactly. And the heavier stuff is also made me
• 51:52
  Speaker 1: think at the last moments of a star. Sometimes when
• 51:55
  Speaker 1: a star is collapsing, it can produce the conditions necessary
• 51:59
  Speaker 1: to make the heavier elements that it couldn't otherwise normally fuse,
• 52:02
  Speaker 1: like if you don't have the conditions necessary to make
• 52:05
  Speaker 1: heavier stuff. Well, at the last few moments of a
• 52:07
  Speaker 1: star's life, when it undergoes gravitational collapse, it creates intense temperature,
• 52:11
  Speaker 1: intense pressure, intense density, and in these last moments it
• 52:15
  Speaker 1: can do what's called supernova nucleosynthesis, where it makes some
• 52:19
  Speaker 1: of these heavier elements gold and europium and other kinds
• 52:23
  Speaker 1: of things can be formed in those moments by supernova.
• 52:26
  Speaker 1: Is that something that we've been able to observe, like
• 52:28
  Speaker 1: a supernova happening in these things sort of being like
• 52:31
  Speaker 1: ejected based on their like spectral characteristics or something even weirder,
• 52:36
  Speaker 1: We find little crystals of it buried in the ocean. Yeah,
• 52:41
  Speaker 1: the specific conditions for making these things are quite unique,
• 52:44
  Speaker 1: and they make these little crystal nodules which we have
• 52:47
  Speaker 1: found like sprayed out through the universe and dug out
• 52:50
  Speaker 1: like from the bottom of the ocean. We have a
• 52:52
  Speaker 1: whole episode about supernova and how people figure this out.
• 52:55
  Speaker 1: And one thing they discovered when they understood this is
• 52:58
  Speaker 1: that it didn't seem to be explaining rething like supernova
• 53:01
  Speaker 1: can make some of these heavier elements, but it can't
• 53:03
  Speaker 1: explain all of it, Like there needed to be another process.
• 53:07
  Speaker 1: There weren't enough supernovas to make all the gold we
• 53:09
  Speaker 1: see in the universe, for example, So there's a completely
• 53:12
  Speaker 1: different way of making these heavier elements sometimes, and that's
• 53:15
  Speaker 1: by combining neutron stars. So neutron stars like the leftover
• 53:20
  Speaker 1: remnant of a really really heavy star. Maybe it had
• 53:23
  Speaker 1: like a supernova and it collapsed, and it leaves this
• 53:26
  Speaker 1: really hot, crazy core with strange nuclear matter, and it's
• 53:30
  Speaker 1: not dense enough to form a black hole. Is just
• 53:32
  Speaker 1: sort of sits there, hot and glowing in the X rays.
• 53:35
  Speaker 1: But sometimes there are two of them, and the two
• 53:37
  Speaker 1: are close enough to each other they'll spiral in and
• 53:40
  Speaker 1: eventually combine and produce like gravitational waves. But in that
• 53:44
  Speaker 1: moment they also produce really heavy elements. So neutron star
• 53:48
  Speaker 1: collisions can make like gold and europeum, you know, we
• 53:52
  Speaker 1: think that for example, in one of these collisions, you
• 53:55
  Speaker 1: can make like five earth masses of gold. That's where
• 53:59
  Speaker 1: we should be doing bas mining. How do we get
• 54:01
  Speaker 1: out there? I think the conditions are a little treacherous,
• 54:05
  Speaker 1: but exactly, it's incredible to think that these fairly rare
• 54:09
  Speaker 1: and dramatic and cataclysmic events are responsible for making so
• 54:13
  Speaker 1: many of the interesting atoms that make our universe fun
• 54:17
  Speaker 1: and unique and make like technology possible. So many of
• 54:20
  Speaker 1: those elements are important for like batteries here on Earth,
• 54:23
  Speaker 1: and we take advantage of their weird properties for all
• 54:25
  Speaker 1: sorts of like chemical processes, and none of that would
• 54:28
  Speaker 1: be possible if we didn't have dramatic and cataclysmic destructive
• 54:32
  Speaker 1: events out there in the universe weirdly producing these things, right. Yeah,
• 54:36
  Speaker 1: you know, I know I say this every week, but
• 54:38
  Speaker 1: every every week I am amazed at the things that
• 54:40
  Speaker 1: physicists have learned about the universe and figured out that
• 54:43
  Speaker 1: just like it blows my mind that we managed to
• 54:45
  Speaker 1: figure all these details out. Yeah, I think one more
• 54:48
  Speaker 1: thing that people should understand about these elements is that
• 54:50
  Speaker 1: if you look at like the frequency of the elements
• 54:53
  Speaker 1: in the universe, you can tell yourself a story like
• 54:55
  Speaker 1: starts out with hydrogen and helium that it falls pretty quickly,
• 54:59
  Speaker 1: and there's a couple of apps. They're like lithium and
• 55:01
  Speaker 1: beryllium and boron are just unstable, so there aren't very
• 55:04
  Speaker 1: many of them, and the heavier elements are less likely.
• 55:06
  Speaker 1: But there's also a really weird zig zag pattern, like
• 55:09
  Speaker 1: the even elements are more common than the odd you know,
• 55:13
  Speaker 1: so like ten is more common than eleven, and forties
• 55:16
  Speaker 1: more common than forty one, and seventy eight is more
• 55:19
  Speaker 1: common than seventy nine, and that's weird. And that's another
• 55:23
  Speaker 1: consequence of this nuclear shell model we were talking about earlier.
• 55:26
  Speaker 1: Having like a certain number of protons and neutrons to
• 55:29
  Speaker 1: fit together into the right pattern makes you more stable.
• 55:32
  Speaker 1: And so this is called the auto Parkins rule that
• 55:35
  Speaker 1: argues that elements with autotomic numbers have one unpaired proton
• 55:39
  Speaker 1: and so are more likely to capture another one, increasing
• 55:42
  Speaker 1: their atomic number. And so really, in the end, everything
• 55:46
  Speaker 1: that we see in the universe, all these elements come
• 55:48
  Speaker 1: from the basic rules of the protons and neutrons, like
• 55:50
  Speaker 1: how you allowed to click them together, what they like
• 55:53
  Speaker 1: to do, what conditions you need to make them do
• 55:56
  Speaker 1: various things. It really does tell you just by looking
• 55:59
  Speaker 1: at the distribution number of elements in the universe sort
• 56:01
  Speaker 1: of what's allowed out there and our history, like how
• 56:05
  Speaker 1: we've been cooking the universe so far, everything from computer
• 56:08
  Speaker 1: chips to chat alright, so spread that on your forkacha
• 56:13
  Speaker 1: and have it for lunch, all right. So thanks everybody
• 56:15
  Speaker 1: for coming along with us on this cosmic culinary journey
• 56:19
  Speaker 1: of creation as we talk about what's out there in
• 56:22
  Speaker 1: the universe, how it's made, and where it all came from.
• 56:25
  Speaker 1: And I hope that gave you an appetite. I'm hungry.
• 56:28
  Speaker 1: Let's go eat. Try to avoid the mercury lace dishes.
• 56:32
  Speaker 1: I'll pass that note on too, Zach, And thanks everybody
• 56:34
  Speaker 1: for joining us. Tune in next time. Thanks by, thanks
• 56:45
  Speaker 1: for listening, and remember that Daniel and Jorge explained. The
• 56:48
  Speaker 1: universe is a production of I Heart Radio. For more
• 56:51
  Speaker 1: podcast form my heart Radio, visit the I heart Radio app,
• 56:55
  Speaker 1: Apple Podcasts, or wherever you listen to your favorite shows.