Latest / Daniel and Kelly’s Extraordinary Universe / Listener Questions #49

Transcript

Listener Questions #49 · Daniel and Kelly’s Extraordinary Universe

• 0:07
  Speaker 1: What else could explain the cosmos besides the Big Bang?
• 0:11
  Speaker 1: Was there a bounce, a steady state, or some stranger
• 0:15
  Speaker 1: cosmic fang?
• 0:16
  Speaker 2: Scurvy, palagra, rickets, and beriberi were once common ways people died.
• 0:22
  Speaker 3: But death by.
• 0:23
  Speaker 2: Nutritional deficiency happens less now, since our foods are fortified.
• 0:28
  Speaker 1: Why does all the dry land pile up in one place,
• 0:31
  Speaker 1: while oceans surround it in every other space?
• 0:35
  Speaker 2: Whatever questions keep you up at night, Daniel and Kelly's
• 0:38
  Speaker 2: answers will make it right.
• 0:40
  Speaker 1: Welcome to Daniel and Kelly's Extraordinary Universe of Listener Questions.
• 0:45
  Speaker 3: Episode 49.
• 0:46
  Speaker 4: 49!
• 0:46
  Speaker 3: What are we.
• 0:47
  Speaker 1: Going to do.
• 1:02
  Speaker 3: When we get to 100?
• 1:02
  Speaker 1: What?
• 1:05
  Speaker 2: We're going to have to pick like the best listener questions,
• 1:09
  Speaker 2: but they're all the best.
• 1:10
  Speaker 3: We can't do that.
• 1:11
  Speaker 1: We'll transmit a special episode from the nursing home in
• 1:14
  Speaker 1: which we live.
• 1:15
  Speaker 3: At that point.
• 1:16
  Speaker 2: I think that's only going to be a couple of
• 1:17
  Speaker 2: years away, Daniel. Are you expecting an imminent decline?
• 1:21
  Speaker 1: Yeah, I think that's fair. I'm already on that decline.
• 1:26
  Speaker 1: Thank you very much. I'm just doing a linear extrapolation.
• 1:30
  Speaker 2: I'm declining pretty fast. And I'm Kelly Wienersmith, who studies
• 1:33
  Speaker 2: parasites and space. And I'm here today with my co-host,
• 1:36
  Speaker 2: universe clumpiness lover. That's what it says under his face
• 1:42
  Speaker 2: in Riverside.
• 1:45
  Speaker 1: I was just listening to the episode about simulations where
• 1:50
  Speaker 1: we joke about all the reasons we love the universe.
• 1:52
  Speaker 1: It's clumpiness. It's lack of clumpiness. It's exactly correct clumpy value.
• 1:57
  Speaker 2: Well, and Daniel expects that I have a memory that
• 2:00
  Speaker 2: is more than the five seconds of a memory that
• 2:02
  Speaker 2: the goldfish has.
• 2:04
  Speaker 3: And so he had to remind me what that meant.
• 2:06
  Speaker 1: Meanwhile, you signed on with Wiener Smith. Very creative, Kelly.
• 2:12
  Speaker 3: It's not supposed to be creative.
• 2:13
  Speaker 2: It's just supposed to be who you are. So here's
• 2:15
  Speaker 2: the thing, right? So we're going to give these audio
• 2:18
  Speaker 2: files to Matt. And if one of us was universe
• 2:20
  Speaker 2: clumpiness lover and one of us was universe clumpiness hater,
• 2:26
  Speaker 2: he'd have to figure out which one was which and
• 2:28
  Speaker 2: it would be confusing.
• 2:29
  Speaker 1: He would know. He would 100% know.
• 2:31
  Speaker 3: All right, because he knows us that well. He knows
• 2:33
  Speaker 3: us that well.
• 2:35
  Speaker 1: He does. And on that episode, we also got a
• 2:37
  Speaker 1: complaint from the listener. He was disappointed that in the
• 2:41
  Speaker 1: episode he didn't get to hear any goats.
• 2:44
  Speaker 3: Oh, I love our listeners so much. And I love
• 2:47
  Speaker 3: my goats so much. But right now I'm traveling.
• 2:49
  Speaker 2: I was at the Rockefeller Archive Center this morning and
• 2:53
  Speaker 2: I just got back to my hotel room. So I'm
• 2:55
  Speaker 2: coming to you from Tarrytown, New York.
• 2:58
  Speaker 1: And there are no goats in Tarrytown and you didn't
• 3:00
  Speaker 1: bring any goats on your research trip?
• 3:02
  Speaker 2: I hope that there are ghosts in Tarrytown, but if
• 3:05
  Speaker 2: you bring a goat into an archive center, some archives
• 3:07
  Speaker 2: are getting eaten.
• 3:12
  Speaker 1: All right. Well, today we're not just here to tease
• 3:13
  Speaker 1: Kelly about traveling with goats. We're here to answer questions
• 3:17
  Speaker 1: from listeners. We're here to respond to the thing we're
• 3:20
  Speaker 1: always asking you to do, which is to engage your curiosity,
• 3:24
  Speaker 1: which is to sit back and wonder about how the
• 3:27
  Speaker 1: universe works and why it makes sense and whether it
• 3:30
  Speaker 1: actually makes sense. And then to write to us when
• 3:33
  Speaker 1: it doesn't click together in your head.
• 3:35
  Speaker 2: And our first question today is for Universe Clumpiness Lover
• 3:39
  Speaker 2: from Luca, who lives in New Jersey, which is the
• 3:42
  Speaker 2: state that I was born in.
• 3:44
  Speaker 1: Hi, Daniel and Kelly.
• 3:45
  Speaker 5: My name is Luca and I live in New Jersey.
• 3:48
  Speaker 5: I'm a longtime listener and I always hear you guys
• 3:51
  Speaker 5: say the Big Bang Theory. And it gets me thinking.
• 3:56
  Speaker 4: Are there any other theories?
• 3:58
  Speaker 5: If so, why haven't I heard of them? Thanks for
• 4:01
  Speaker 5: answering my question.
• 4:02
  Speaker 2: Bye.
• 4:02
  Speaker 3: Ooh, this is a good question.
• 4:04
  Speaker 2: Okay, so do you think we should start by, like,
• 4:08
  Speaker 2: I know he said, all right, we've all heard about
• 4:09
  Speaker 2: the Big Bang, but here on DKEU, we take nothing
• 4:13
  Speaker 2: for granted. So maybe we should start by, like, clarifying
• 4:16
  Speaker 2: what the Big Bang is?
• 4:17
  Speaker 1: I think that's actually important because it's going to set
• 4:19
  Speaker 1: the stage for the answer. See, the Big Bang is
• 4:23
  Speaker 1: something very specific in the scientific community. It's an idea
• 4:27
  Speaker 1: we have about how the universe has expanded. how it's
• 4:30
  Speaker 1: gone from dense to less dense. But in popular science,
• 4:34
  Speaker 1: it's something very, very different. And often when people say
• 4:37
  Speaker 1: the Big Bang Theory, it's not clear which they mean.
• 4:41
  Speaker 1: And so here, of course, we're talking about science, but
• 4:43
  Speaker 1: we're doing popular science, so let's clarify. In popular imagination,
• 4:48
  Speaker 1: the Big Bang is an explosion of a tiny dot
• 4:52
  Speaker 1: of matter out into empty space to begin the universe.
• 4:57
  Speaker 1: And that's a story widely told and widely heard and unfortunately, very,
• 5:03
  Speaker 1: very wrong. It's not our scientific description of the Big Bang.
• 5:07
  Speaker 3: As we've discussed on the show in the past.
• 5:10
  Speaker 1: Exactly. And to put a fine point on it, the
• 5:12
  Speaker 1: Big Bang was not an explosion of a dot of
• 5:14
  Speaker 1: matter into empty space. There was no empty space. There's
• 5:18
  Speaker 1: never been empty space. Matter was everywhere. Otherwise, you'd have
• 5:22
  Speaker 1: to ask like, Where was that point of matter? Why
• 5:25
  Speaker 1: was it here and not there? Where are we relative
• 5:27
  Speaker 1: to it? Et cetera, et cetera. The universe has no center,
• 5:29
  Speaker 1: no special places. Matter was everywhere. We don't know where
• 5:33
  Speaker 1: that matter came from. The Big Bang Theory just says
• 5:37
  Speaker 1: the universe was filled with hot, dense matter, and then
• 5:40
  Speaker 1: that cooled and expanded. It also doesn't claim that that's
• 5:44
  Speaker 1: the beginning of the universe, that that's how anything started.
• 5:47
  Speaker 1: It just says that's how it was, and now it's
• 5:50
  Speaker 1: changing in this way. So the Big Bang Theory It's
• 5:53
  Speaker 1: not an explosion into empty space and not a story
• 5:57
  Speaker 1: about the beginning or the creation of the universe. It
• 5:59
  Speaker 1: just says you go back in time 14 billion years.
• 6:02
  Speaker 1: The universe was hot and dense. Since then, it's expanded
• 6:06
  Speaker 1: and cooled and become more dilute.
• 6:08
  Speaker 3: Yes.
• 6:09
  Speaker 1: Excellent.
• 6:10
  Speaker 3: Okay.
• 6:10
  Speaker 2: So is that like the main thing that all physicists
• 6:14
  Speaker 2: agree on was happening at that time?
• 6:15
  Speaker 3: Or is there a debate about the Big Bang?
• 6:18
  Speaker 1: There's always debate and there's always disagreement in any sort
• 6:21
  Speaker 1: of healthy field. But the thing to know is that
• 6:24
  Speaker 1: while there are some details to be worked out, there's
• 6:27
  Speaker 1: a lot of evidence, like a lot with three underlines,
• 6:32
  Speaker 1: italic evidence for this expansion.
• 6:35
  Speaker 3: Calm it down, universe clumpiness lover.
• 6:40
  Speaker 1: You know, well, this is exactly how the universe got
• 6:43
  Speaker 1: its wonderful clumpiness, you know, is all this expansion and contraction.
• 6:47
  Speaker 1: We have evidence that the universe was once much denser
• 6:50
  Speaker 1: because we've seen light emitted by that dense plasma. That's
• 6:54
  Speaker 1: the cosmic microwave background radiation. We've run simulations that explore
• 6:58
  Speaker 1: how can you get a universe that looks like this?
• 7:00
  Speaker 1: And it's totally consistent with the universe was once filled
• 7:04
  Speaker 1: with hot, dense plasma with little bits of clumpiness in it.
• 7:07
  Speaker 1: which then got more clumpy as gravity did its work
• 7:10
  Speaker 1: as things expanded and cooled. There's lots and lots of
• 7:13
  Speaker 1: independent lines of evidence that show us that the universe
• 7:16
  Speaker 1: is getting less dense over time. So now Luca is asking,
• 7:20
  Speaker 1: are there other theories than the Big Bang Theory? And
• 7:23
  Speaker 1: it's pretty hard to come up with another theory when
• 7:26
  Speaker 1: there's so much overwhelming evidence for the Big Bang Theory. Now,
• 7:30
  Speaker 1: there used to be. Before we had all this evidence
• 7:33
  Speaker 1: for the Big Bang, there was another theory. It was
• 7:35
  Speaker 1: called the Steady State Theory. People saw, hey, the universe
• 7:38
  Speaker 1: is expanding. Things are running away from each other. Space
• 7:41
  Speaker 1: is increasing between galaxies. But it felt weird to imagine
• 7:45
  Speaker 1: that the universe was getting less dense. So the alternative,
• 7:48
  Speaker 1: the steady state theory, said that, yes, the universe is expanding,
• 7:52
  Speaker 1: but somehow new matter is being constantly created. So the
• 7:56
  Speaker 1: overall appearance stays statistically constant. The density was flat, right?
• 8:01
  Speaker 1: The density was not decreasing. And that made sense to
• 8:04
  Speaker 1: some people because it suggested that the universe was sort
• 8:07
  Speaker 1: of static or constant in a way that wasn't denser
• 8:11
  Speaker 1: earlier and less dense later. And so that was the
• 8:14
  Speaker 1: major competitor for the Big Bang, but it was basically
• 8:16
  Speaker 1: ruled out when we saw the cosmic microwave background radiation
• 8:20
  Speaker 1: and we looked at the evolution of galaxies. It just
• 8:23
  Speaker 1: does not describe the universe as we see it. And
• 8:26
  Speaker 1: there's Big Bang nucleosynthesis, there's the large-scale structure, there's the
• 8:30
  Speaker 1: baryonic acoustic oscillations, all the stuff we've talked about in
• 8:32
  Speaker 1: the podcast a lot. There are no realistic theories that
• 8:35
  Speaker 1: describe the universe that don't involve expansion because we've seen
• 8:39
  Speaker 1: expansion in so many different ways. And fundamentally, that's what
• 8:43
  Speaker 1: the Big Bang is. It just says the universe is
• 8:45
  Speaker 1: expanding and getting more dilute. So are there alternative theories
• 8:50
  Speaker 1: to the Big Bang? Are there theories that the universe
• 8:52
  Speaker 1: isn't getting more dilute? No, because we see that it's happening.
• 8:56
  Speaker 1: And so none of those theories would be consistent with reality.
• 9:00
  Speaker 3: Okay, so.
• 9:01
  Speaker 2: You said, are there theories that the universe isn't getting
• 9:04
  Speaker 2: more dilute? So is that like the feature of a
• 9:08
  Speaker 2: not Big Bang theory?
• 9:09
  Speaker 5: Yeah.
• 9:10
  Speaker 2: Because I feel like we could be tracking that, but
• 9:11
  Speaker 2: we could also be tracking like, are we talking about
• 9:14
  Speaker 2: the start of the universe or not? Because the Big
• 9:16
  Speaker 2: Bang theory is not talking about the start of the universe.
• 9:18
  Speaker 1: That's right.
• 9:19
  Speaker 2: So I think what's confusing me. So here's some things
• 9:21
  Speaker 2: I remember you have told me because I listen. The
• 9:23
  Speaker 2: universe is expanding and it's expanding at a faster rate.
• 9:27
  Speaker 2: And as it expands, it gets filled in with dark.
• 9:30
  Speaker 2: Is it energy or matter?
• 9:31
  Speaker 5: Energy.
• 9:32
  Speaker 3: Ah, not matter.
• 9:33
  Speaker 2: OK, so it is getting more dilute because it's not
• 9:36
  Speaker 2: more matter that's being produced. It's more energy. And energy
• 9:39
  Speaker 2: is not matter. But sometimes that's confusing.
• 9:44
  Speaker 3: And so steady state is different than the Big Bang.
• 9:46
  Speaker 2: How?
• 9:47
  Speaker 3: If all of that is true.
• 9:49
  Speaker 1: The steady state theory says that there is no drop
• 9:52
  Speaker 1: in density, that new matter is being created. The universe
• 9:54
  Speaker 1: is expanding, it's getting bigger, but somehow new galaxies are
• 9:58
  Speaker 1: popping into existence to fill... in that space. So density
• 10:01
  Speaker 1: is not dropping. And the reason I want to emphasize
• 10:03
  Speaker 1: that the Big Bang theory is just basically the statement
• 10:06
  Speaker 1: that the universe is expanding and density is dropping is
• 10:09
  Speaker 1: to highlight that there are no alternatives to that because
• 10:12
  Speaker 1: we see that that's what's happening. But I suspect what
• 10:14
  Speaker 1: Luca is really curious about are other theories of what
• 10:17
  Speaker 1: happens before that hot, dense state. Where does that come from?
• 10:22
  Speaker 1: He's probably imagining the Big Bang theory as an origin
• 10:25
  Speaker 1: of the universe theory, which technically it's not, and wondering
• 10:28
  Speaker 1: about other origin of the universe theories. And there, there's
• 10:32
  Speaker 1: a whole wide open proliferation of theories because we don't
• 10:35
  Speaker 1: have a lot of data. Since that hot, dense state
• 10:38
  Speaker 1: and the expansion, we have lots of measurements. We've pinned
• 10:40
  Speaker 1: it down. We know things are expanding. We can describe
• 10:43
  Speaker 1: that as the Big Bang theory. Before that, it's still very,
• 10:46
  Speaker 1: very murky, which means lots of room for speculation and
• 10:49
  Speaker 1: crazy theories about where all that matter came from. Remember,
• 10:53
  Speaker 1: the Big Bang does not tell us where the hot,
• 10:56
  Speaker 1: dense stuff came from. If the universe was infinite, it
• 10:58
  Speaker 1: was already filled with glorious, glowing matter. And the Big
• 11:02
  Speaker 1: Bang theory does not tell us where. We need another theory,
• 11:06
  Speaker 1: a pre-Big Bang theory, to tell us where that came from.
• 11:09
  Speaker 1: And there are definitely some exciting options there to talk about.
• 11:12
  Speaker 3: Oh, is this what Ethan, who we had on our show,
• 11:15
  Speaker 3: does he do a bunch of this stuff?
• 11:16
  Speaker 1: Yes. Ethan Siegel is a cosmologist and he does early
• 11:19
  Speaker 1: universe cosmology. He's an expert in that. He has a
• 11:22
  Speaker 1: great podcast called Starts with a Bang. Also, it's a blog.
• 11:25
  Speaker 1: You all should check his stuff out. He's great. Also,
• 11:28
  Speaker 1: he wears a kilt and has a wonderful mustache.
• 11:30
  Speaker 3: He is a super cool dude.
• 11:32
  Speaker 2: Yes. I was disappointed that I only got to see
• 11:35
  Speaker 2: him from the shoulders up with our video, but he
• 11:38
  Speaker 2: explains the cool kilt he was wearing that day.
• 11:40
  Speaker 1: He probably also appropriately enjoys the universe's clumpiness.
• 11:44
  Speaker 2: Did I come off as a clumpiness hater in the
• 11:47
  Speaker 2: last episode? Because I don't remember that at all. I
• 11:49
  Speaker 2: don't feel like I would be anti-clumpiness.
• 11:51
  Speaker 1: No, but you're definitely a mocker of universe clumpiness lovers.
• 11:55
  Speaker 3: Wow.
• 11:56
  Speaker 1: Which is, you know, not being very supportive.
• 11:59
  Speaker 2: I'm so sorry to all one of you. All right, so.
• 12:04
  Speaker 1: Let's get back to Luca's question. you know, are there
• 12:08
  Speaker 1: explanations for where all this stuff came from? And there
• 12:11
  Speaker 1: definitely are. And remember, these are all speculative and there's
• 12:14
  Speaker 1: no data that will tell us one or the other.
• 12:17
  Speaker 1: One of the most popular is called inflation. And it's
• 12:20
  Speaker 1: sort of like a super version of the Big Bang.
• 12:22
  Speaker 1: The Big Bang tells us the universe expanded since that hot,
• 12:25
  Speaker 1: dense state. Inflation says, what if there was crazy, amazing
• 12:29
  Speaker 1: expansion before that, where even tinier quantum fluctuations were or
• 12:34
  Speaker 1: expand it out to macroscopic variations in density. And that
• 12:38
  Speaker 1: could explain how you got a hot dense plasma that's
• 12:41
  Speaker 1: a little bit heavier here and a little bit less
• 12:43
  Speaker 1: dense there.
• 12:44
  Speaker 3: Okay.
• 12:45
  Speaker 1: And it's super cool because the inflation theory says, start
• 12:48
  Speaker 1: with the universe and fill it with this inflaton field
• 12:50
  Speaker 1: that causes this insane expansion. You know, factors of like
• 12:54
  Speaker 1: 10 to the 30 expansion every 10 to the minus
• 12:57
  Speaker 1: 30 seconds. Just like hard to even really put your
• 13:01
  Speaker 1: mind around.
• 13:02
  Speaker 5: Yeah.
• 13:02
  Speaker 1: And the whole universe is expanding that way. But then
• 13:05
  Speaker 1: occasionally points in this field will decay and they'll turn
• 13:08
  Speaker 1: into normal matter like our universe. And so in the
• 13:12
  Speaker 1: inflation theory, our whole universe is like one dot in
• 13:16
  Speaker 1: this vast inflating inflaton field that turned into normal matter.
• 13:20
  Speaker 1: And then you have our Big Bang, et cetera, et cetera.
• 13:23
  Speaker 1: But the rest of the universe is still inflating. So
• 13:27
  Speaker 1: we stopped inflating 14 billion years ago, but the rest
• 13:29
  Speaker 1: of it continued. And there might be other dots out
• 13:32
  Speaker 1: there that also turned into normal matter and turned into
• 13:35
  Speaker 1: little pocket bubble universes that are now normal matter like ours.
• 13:39
  Speaker 1: But we're separated from them by huge, vast distances of
• 13:43
  Speaker 1: this constantly inflating inflatant field. So we have no way
• 13:47
  Speaker 1: to ever interact with them. So that's this picture of
• 13:50
  Speaker 1: the universe filled with this insanely expanding inflatant field and
• 13:53
  Speaker 1: then these little bubble universes, one of which is ours.
• 13:57
  Speaker 3: Is there any evidence for that?
• 13:59
  Speaker 1: There's no direct evidence for inflation. It's a really cool
• 14:02
  Speaker 1: theory because it solves some problems we've talked in the
• 14:04
  Speaker 1: podcast about before, like how the universe is so flat
• 14:08
  Speaker 1: or the temperature smoothness of that early universe plasma. And
• 14:12
  Speaker 1: so it's very compelling theoretically, and it does answer some questions,
• 14:16
  Speaker 1: but it's no direct evidence for it. We might one
• 14:19
  Speaker 1: day see direct evidence for it. The limitation is that
• 14:22
  Speaker 1: we haven't seen anything earlier than the cosmic microwave background radiation.
• 14:27
  Speaker 1: because that's the first moment the universe became transparent. So
• 14:30
  Speaker 1: the light that was emitted could fly through the universe
• 14:33
  Speaker 1: and be picked up by our telescopes. Everything before that
• 14:36
  Speaker 1: was absorbed. But the universe is transparent to different kinds
• 14:40
  Speaker 1: of things earlier, like gravitational waves can pass through lots
• 14:45
  Speaker 1: of stuff. And so gravitational waves from before that hot,
• 14:48
  Speaker 1: dense plasma that made the CMB might still be out
• 14:51
  Speaker 1: there in the universe, and we could pick them up
• 14:53
  Speaker 1: and measure them and learn things about the even earlier
• 14:57
  Speaker 1: universe and get hints of inflation. There was a measurement
• 15:00
  Speaker 1: a few years ago by Brian Keating and collaborators who
• 15:03
  Speaker 1: thought they saw signs of inflation in the gravitational waves,
• 15:07
  Speaker 1: but it turns out to have just been dust. And
• 15:09
  Speaker 1: they took a picture of somebody's PowerPoint slide and used
• 15:12
  Speaker 1: that as a crucial part of their calculation and got
• 15:15
  Speaker 1: the answer wrong. So long story short, we don't have
• 15:19
  Speaker 1: evidence for inflation, but we might one day.
• 15:22
  Speaker 3: Oh, and didn't Keating write about that in his book
• 15:24
  Speaker 3: or something?
• 15:25
  Speaker 1: Yes, he wrote a book called Losing the Nobel Prize. Exactly.
• 15:28
  Speaker 3: Oh, man.
• 15:29
  Speaker 2: One of the good things about the field that I
• 15:31
  Speaker 2: work in is you're not getting the Nobel Prize.
• 15:33
  Speaker 3: So you don't have to worry about losing it, right?
• 15:35
  Speaker 3: That doesn't keep you up at night.
• 15:37
  Speaker 1: No, you're just getting weird parasites.
• 15:39
  Speaker 5: Yay.
• 15:39
  Speaker 4: Yay.
• 15:40
  Speaker 5: Yay.
• 15:42
  Speaker 1: So that's a very one-directional theory. Other theories are like
• 15:45
  Speaker 1: cyclic theories that suggest that maybe the universe has like
• 15:49
  Speaker 1: repeated cycles of expansion and contraction. Yeah. Each Big Bang
• 15:55
  Speaker 1: is like a transition from a previous cosmic phase. So
• 15:59
  Speaker 1: for example, Penrose is a theory of cyclic cosmology where
• 16:02
  Speaker 1: the end of the universe looks very similar to the
• 16:04
  Speaker 1: beginning of the universe and could essentially recycle the Big Bang.
• 16:09
  Speaker 1: This is an interesting idea, and a lot of people
• 16:11
  Speaker 1: like this idea. When they hear about it, they write
• 16:13
  Speaker 1: to me, and they're like, ooh, have you heard this idea?
• 16:15
  Speaker 1: It's very cool. There were claims that there was evidence
• 16:18
  Speaker 1: for this. Patterns we saw in the Cosmic Microwave Background
• 16:22
  Speaker 1: that indicated evidence from a previous universe, but independent analysis
• 16:27
  Speaker 1: didn't hold that up. And then reanalysis of the original
• 16:29
  Speaker 1: claims fell apart. So bottom line is there was a
• 16:33
  Speaker 1: bit of hoopla and you might find some pop-sci articles
• 16:35
  Speaker 1: suggesting that there is evidence for us, but there isn't
• 16:39
  Speaker 1: any evidence for a cyclic universe. That doesn't mean it's
• 16:41
  Speaker 1: not happening, but theoretically it's a bit of a challenge
• 16:45
  Speaker 1: to construct like a physically viable mechanism that generates evidence
• 16:50
  Speaker 1: this cycle and respects the laws of thermodynamics, et cetera,
• 16:54
  Speaker 1: et cetera, from cycle to cycle. But it could be
• 16:58
  Speaker 1: our universe.
• 16:59
  Speaker 3: Okay.
• 16:59
  Speaker 2: Well, I'm kind of glad that there's not loads of
• 17:02
  Speaker 2: evidence for this one because the idea of our universe
• 17:04
  Speaker 2: contracting makes me feel a little uncomfortable. And that sounds
• 17:08
  Speaker 2: like the kind of thing that could end humanity. But
• 17:10
  Speaker 2: all right, let's talk about a new.
• 17:12
  Speaker 3: Are there more theories?
• 17:14
  Speaker 1: Well, the next one is not going to make you
• 17:15
  Speaker 1: more comfortable because the next one says... The universe didn't
• 17:19
  Speaker 1: begin with a singularity. It began with another one contracting.
• 17:22
  Speaker 1: So it's called the big bounce.
• 17:24
  Speaker 5: Oh, no.
• 17:25
  Speaker 1: Essentially, the expansion happened in reverse. Things got really, really
• 17:28
  Speaker 1: dense and then reversed. And there are some theories of
• 17:32
  Speaker 1: loop quantum gravity approaches to bringing quantum mechanics and gravity together,
• 17:37
  Speaker 1: which naturally lead to a big bounce. And so from
• 17:40
  Speaker 1: a theoretical point of view, that's also very cool. And
• 17:43
  Speaker 1: so in this picture– You know, the Big Bang is real.
• 17:47
  Speaker 1: It's just not the beginning of the universe. It's just
• 17:49
  Speaker 1: that the expansion was preceded by a contraction in those theories.
• 17:54
  Speaker 3: Okay.
• 17:55
  Speaker 1: And then maybe my favorite kind of out there idea
• 17:58
  Speaker 1: that sounds really fun to think about while smoking banana
• 18:00
  Speaker 1: peels is the like time symmetric universe. We have these
• 18:05
  Speaker 1: symmetries in our universe, time symmetry, charge symmetry, parity symmetry.
• 18:09
  Speaker 1: And you can combine them all together to make charge
• 18:12
  Speaker 1: parity time symmetry. We flip all of them. And we
• 18:15
  Speaker 1: think that the universe is symmetric under all three flips simultaneously.
• 18:19
  Speaker 1: If you go backwards in time and change positive to
• 18:23
  Speaker 1: negative and flip everything through a mirror, physics should look
• 18:26
  Speaker 1: all the same. So this inspires the idea that maybe
• 18:30
  Speaker 1: at the beginning of the universe, sort of two universes
• 18:33
  Speaker 1: were created, one going forward in time and one going
• 18:36
  Speaker 1: backwards in time. And there's this like mirror image universes
• 18:41
  Speaker 1: going forwards and backwards. And This actually got a lot
• 18:43
  Speaker 1: of press because one thing it suggests is the existence
• 18:47
  Speaker 1: of these very high mass dark matter particles, which would
• 18:50
  Speaker 1: coalesce in the center of the Earth. And there's an
• 18:53
  Speaker 1: experiment in Antarctica that saw weird particles that might be
• 18:57
  Speaker 1: coming from the center of the Earth. And it received
• 18:59
  Speaker 1: a lot of popular pressing. NASA has discovered a parallel
• 19:02
  Speaker 1: universe right next to ours, man. Which, of course, it didn't.
• 19:06
  Speaker 1: But it got a lot of clicks. So that's another
• 19:08
  Speaker 1: fun theory about what happened before the Big Bang. And,
• 19:12
  Speaker 1: you know, the takeaway is there's lots of ideas here.
• 19:15
  Speaker 1: We don't have data to pin any of these down.
• 19:19
  Speaker 1: But all of these are pre-Big Bang. The actual Big
• 19:21
  Speaker 1: Bang theory is pretty well established. You never say never
• 19:25
  Speaker 1: because you could always learn something which upends consensus and
• 19:28
  Speaker 1: physicists would love to do that. But there's so much
• 19:32
  Speaker 1: overwhelming data for the expansion of the universe itself. that
• 19:35
  Speaker 1: there aren't really viable alternatives to the Big Bang Theory.
• 19:38
  Speaker 1: The same way there aren't real viable alternatives to evolution
• 19:42
  Speaker 1: or heliocentrism.
• 19:47
  Speaker 2: Right.
• 19:48
  Speaker 3: All right.
• 19:48
  Speaker 2: Well, thank you to Luca for this awesome question. And
• 19:51
  Speaker 2: let's see if universe clumpiness lover gave a satisfying answer.
• 19:55
  Speaker 2: You know, I was thinking I would update mine to
• 19:57
  Speaker 2: say goat lover, but it's got a definite different vibe.
• 20:02
  Speaker 2: So I'm going to not go there.
• 20:04
  Speaker 1: Hi, Daniel and Kelly.
• 20:07
  Speaker 5: Thank you so much for answering my question. I think
• 20:09
  Speaker 5: you interpreted it very well. I've had that question on
• 20:13
  Speaker 5: my mind for a while, and you really helped clear
• 20:15
  Speaker 5: it up. I enjoyed learning about all of the theories,
• 20:19
  Speaker 5: especially your favorite, Daniel, the time-symmetric universe. And I also
• 20:24
  Speaker 5: like the cyclic universe, except for the fact that we
• 20:26
  Speaker 5: all die in the end. Thanks again.
• 20:28
  Speaker 3: Keep up the great work.
• 20:29
  Speaker 2: Bye.
• 20:49
  Speaker 1: All right. We're back and we're answering questions from listeners.
• 20:53
  Speaker 1: And this question is going to hit a special chord
• 20:55
  Speaker 1: in my household.
• 20:57
  Speaker 2: Oh, well, maybe that is the motivation for the question,
• 20:59
  Speaker 2: because actually you might see that I did not include
• 21:02
  Speaker 2: the name of the question asker.
• 21:04
  Speaker 3: Do you know who asked this question?
• 21:06
  Speaker 1: I do not. Was it somebody in my household?
• 21:09
  Speaker 3: It was you.
• 21:10
  Speaker 1: What?
• 21:14
  Speaker 2: Two years ago, when we started podcasting, I guess it's
• 21:18
  Speaker 2: a little short of two years. Our podiversary is in October.
• 21:21
  Speaker 2: But you wrote me and you were like, oh, I
• 21:23
  Speaker 2: would love to hear about diseases that it turns out
• 21:26
  Speaker 2: are really easy to fix. And the diseases I could
• 21:30
  Speaker 2: come up with were nutritional deficiencies that are easy to
• 21:34
  Speaker 2: fix by just getting the right thing in your diet.
• 21:37
  Speaker 2: And it took me two years, but as I was
• 21:40
  Speaker 2: reading about scurvy and pellagra recently, I was like, oh.
• 21:43
  Speaker 2: I can cross Daniel's questions off my list. So anyway,
• 21:47
  Speaker 2: I've kept this on a checklist for a long time.
• 21:49
  Speaker 3: So Daniel.
• 21:49
  Speaker 1: That's amazing.
• 21:50
  Speaker 3: This one's for you.
• 21:51
  Speaker 1: It's amazing that this is my question because scurvy is
• 21:55
  Speaker 1: something we talk about in my household all the time.
• 21:58
  Speaker 1: It's Katrina's go-to joke. When we are struggling to get
• 22:01
  Speaker 1: our kids to eat vegetables or fresh foods, she's like,
• 22:05
  Speaker 1: oh my God, it'd be the biggest parenting fail of
• 22:07
  Speaker 1: all time if you guys died of scurvy. Because she's
• 22:10
  Speaker 1: always worried that like, If they just eat bread and
• 22:13
  Speaker 1: cheese or like peanut butter and crackers, that's like they're
• 22:16
  Speaker 1: not getting enough, you know, whatever nutrients they need.
• 22:20
  Speaker 3: Ascorbic acid.
• 22:21
  Speaker 1: That would be pretty embarrassing to have your kids die
• 22:23
  Speaker 1: of scurvy in 2026.
• 22:24
  Speaker 3: It would be super embarrassing.
• 22:26
  Speaker 2: The good news is they probably have about a three
• 22:28
  Speaker 2: month supply stored up. So you've got about three months
• 22:31
  Speaker 2: to get them to eat vitamin C after they've had
• 22:34
  Speaker 2: a long stretch of just like bread and whatnot. But yeah,
• 22:37
  Speaker 2: that would be pretty embarrassing. But thankfully, scurvy is pretty
• 22:43
  Speaker 2: rare these days. I read this book called Scurvy, well-named,
• 22:48
  Speaker 2: by Stephen Bowne. And he was saying that there's an
• 22:51
  Speaker 2: estimate that about two million sailors died from scurvy during
• 22:54
  Speaker 2: what's called the Age of Sail. And so this is
• 22:57
  Speaker 2: like in between Columbus, sailing for America, and when we
• 23:02
  Speaker 2: start getting steam-powered ships.
• 23:04
  Speaker 3: So that's a lot of people dying from scurvy.
• 23:06
  Speaker 1: That is a lot of people dying.
• 23:08
  Speaker 3: Yeah.
• 23:09
  Speaker 1: But tell me, like, what causes scurvy? What is scurvy anyway?
• 23:13
  Speaker 3: So let's start with the symptoms of scurvy. So what
• 23:15
  Speaker 3: is scurvy?
• 23:15
  Speaker 2: Scurvy is when essentially anything in your body that requires
• 23:19
  Speaker 2: collagen starts failing.
• 23:21
  Speaker 1: What is collagen exactly?
• 23:23
  Speaker 3: Good point.
• 23:24
  Speaker 2: So women always hear about, oh, you need more collagen
• 23:26
  Speaker 2: because it like gives your facial skin its firmness or whatnot.
• 23:30
  Speaker 2: So you need to like rub collagen all over your face.
• 23:33
  Speaker 2: And I guess those ads are not sent to everybody.
• 23:36
  Speaker 2: Your face looks disturbed. What are you looking at right now?
• 23:40
  Speaker 1: I'm imagining rubbing collagen in my face, but I have
• 23:43
  Speaker 1: no idea what collagen looks like. So what am I
• 23:45
  Speaker 1: rubbing in my face right now? Oh, okay.
• 23:47
  Speaker 2: Yeah, I guess I don't exactly know what it looks like,
• 23:49
  Speaker 2: but it's a protein in your body that's used for
• 23:51
  Speaker 2: structural stuff. Okay.
• 23:53
  Speaker 5: Okay.
• 23:53
  Speaker 2: So when you don't have that, a bunch of structural
• 23:56
  Speaker 2: stuff falls apart. So like your teeth don't stay in
• 23:59
  Speaker 2: place anymore.
• 23:59
  Speaker 3: They fall out.
• 24:01
  Speaker 2: You start feeling weak physically. Old wounds that were held together,
• 24:04
  Speaker 2: the collagen sort of is no longer there to hold
• 24:06
  Speaker 2: it together and they start opening up again. Other things
• 24:10
  Speaker 2: that happen is you become really like exhausted and lethargic
• 24:13
  Speaker 2: and Your gums start bleeding. All of your connective tissues
• 24:17
  Speaker 2: start to fall apart. And there's just, you know, stories
• 24:19
  Speaker 2: about sailors who essentially can't get themselves out of bed
• 24:21
  Speaker 2: anymore and just like die in their beds.
• 24:24
  Speaker 1: So these things need a constant supply of collagen. Like
• 24:27
  Speaker 1: I imagined you build some bit of your body. You've
• 24:30
  Speaker 1: used that resource. You've built it. You don't need to
• 24:32
  Speaker 1: constantly come by and resupply it with collagen. So why
• 24:36
  Speaker 1: do you need new collagen all the time?
• 24:38
  Speaker 2: Yeah, so there are some things that you do need
• 24:40
  Speaker 2: to keep replenishing. And so like, I guess you need
• 24:43
  Speaker 2: to keep replenishing like the connections between your teeth and
• 24:46
  Speaker 2: the rest of your face. And you need to keep
• 24:49
  Speaker 2: working on like places where there have been wounds because
• 24:52
  Speaker 2: those seem to be some of the first things that
• 24:53
  Speaker 2: fall apart when you get sick. And I guess I
• 24:55
  Speaker 2: had not realized that you need to keep putting more
• 24:58
  Speaker 2: and more collagen into stuff. But, you know, most of
• 25:00
  Speaker 2: the cells in your body turn over. It's not too
• 25:02
  Speaker 2: surprising that the structural stuff in your body needs to
• 25:05
  Speaker 2: be replenished from time to time.
• 25:07
  Speaker 1: Okay. I guess you need a constant, like, supply of
• 25:09
  Speaker 1: calcium to keep your bones strong, this kind of stuff.
• 25:12
  Speaker 2: Yeah, they're constantly being built up and broken down. So, yeah,
• 25:15
  Speaker 2: you also need calcium for your bones at all times.
• 25:18
  Speaker 1: All right. So if you don't have enough collagen, then
• 25:21
  Speaker 1: stuff breaks down and your teeth fall out and you
• 25:24
  Speaker 1: turn into a big rubber band.
• 25:26
  Speaker 3: Exactly.
• 25:26
  Speaker 5: Right.
• 25:27
  Speaker 2: And so the problem is that you need ascorbic acid,
• 25:30
  Speaker 2: which is also known as vitamin C, to create an
• 25:33
  Speaker 2: enzyme that is used to make collagen.
• 25:36
  Speaker 1: Oh, I see.
• 25:36
  Speaker 2: So if you don't get vitamin C or ascorbic acid,
• 25:38
  Speaker 2: you don't get collagen and everything just kind of starts
• 25:41
  Speaker 2: falling apart.
• 25:41
  Speaker 1: Mm-hmm.
• 25:42
  Speaker 2: But it took us a really long time to figure
• 25:45
  Speaker 2: this out. And the reason it took us so long
• 25:48
  Speaker 2: is that, like, yes, you can get– so, you know,
• 25:50
  Speaker 2: Katrina is worried about the kids not eating enough fresh stuff. But, like,
• 25:54
  Speaker 2: if you look at fresh stuff, ascorbic acid or vitamin
• 25:57
  Speaker 2: C is not, like, evenly distributed amongst fruits and vegetables. So,
• 26:01
  Speaker 2: for example, oranges and lemons have, like, 10 times as
• 26:06
  Speaker 2: much ascorbic acid as a lime does. And while cucumbers
• 26:10
  Speaker 2: have like no ascorbic acid, broccoli seems to have.
• 26:13
  Speaker 3: Loads of it.
• 26:14
  Speaker 2: And there's no really easy way to predict by looking
• 26:17
  Speaker 2: at something like, oh, that should have a lot of
• 26:18
  Speaker 2: ascorbic acid and that shouldn't. But another thing that complicated
• 26:23
  Speaker 2: the story is that then you look at people like
• 26:25
  Speaker 2: the Inuits. who don't get to eat a lot of
• 26:28
  Speaker 2: fresh food, right? They live in an area where they
• 26:30
  Speaker 2: don't have access to loads of fruits and vegetables. And
• 26:32
  Speaker 2: so you'd think, okay, well, it can't be fresh fruits
• 26:34
  Speaker 2: and vegetables because the Inuits aren't eating loads of fresh food,
• 26:38
  Speaker 2: but they're fine. But it turns out that there's a
• 26:41
  Speaker 2: lot of vitamin C in kidneys and livers. And so
• 26:44
  Speaker 2: when they capture animals, those are parts of the animal
• 26:48
  Speaker 2: that they tend to eat that, for example, British sailors
• 26:51
  Speaker 2: weren't tending to eat. Right. Additionally, if you bruise a fruit,
• 26:57
  Speaker 2: the ascorbic acid starts to go away. If you cook
• 27:01
  Speaker 2: the fruit in a copper pan, that makes it so
• 27:05
  Speaker 2: that the ascorbic acid goes away.
• 27:07
  Speaker 1: Chemistry.
• 27:08
  Speaker 3: Chemistry, right?
• 27:09
  Speaker 2: And so there's so many different ways that even if
• 27:12
  Speaker 2: you're on the right track, you could do something that
• 27:15
  Speaker 2: you weren't expecting. If you're preparing a bunch of lemon
• 27:18
  Speaker 2: juice for a really long voyage, but you happen to
• 27:20
  Speaker 2: boil it first in a copper pot... Maybe you're going
• 27:23
  Speaker 2: to get scurvy because you've lost a bunch of it
• 27:25
  Speaker 2: on the way. And so there were times throughout history
• 27:27
  Speaker 2: where we actually like kind of were on the right
• 27:30
  Speaker 2: track and then we'd totally throw ourselves off. So, for example,
• 27:35
  Speaker 2: when the British East India Company started and this was
• 27:39
  Speaker 2: around like sixteen hundred. They actually had a pretty good
• 27:42
  Speaker 2: sense that oranges and lemons were important for warding off scurvy.
• 27:47
  Speaker 2: And so not only did they bring that stuff with them,
• 27:49
  Speaker 2: but they also like set up stops along their routes
• 27:53
  Speaker 2: where they would like, you know, stop and grab some
• 27:54
  Speaker 2: limes or some lemons or something.
• 27:56
  Speaker 3: And that helps them. But they did such.
• 27:58
  Speaker 2: A good job of warding off scurvy that the next
• 28:01
  Speaker 2: generation of people were like, this scurvy thing isn't really
• 28:04
  Speaker 2: a problem.
• 28:04
  Speaker 3: We're like making all these extra stops for lemons and limes.
• 28:08
  Speaker 3: But like, why are we doing that? What a waste
• 28:10
  Speaker 3: of time.
• 28:10
  Speaker 1: I don't need an umbrella. It's not raining under here.
• 28:13
  Speaker 3: Yes, exactly.
• 28:14
  Speaker 2: Right. And so that knowledge got lost. But then there
• 28:18
  Speaker 2: was this guy named James Lind. And in 1747, he
• 28:22
  Speaker 2: was on the HMS Salisbury. And he was like, look,
• 28:25
  Speaker 2: we've got to figure this scurvy thing out. There were
• 28:27
  Speaker 2: all kinds of like really bad treatments out there. And
• 28:31
  Speaker 2: the like common denominator seemed to be that they were
• 28:34
  Speaker 2: things that were cheap.
• 28:35
  Speaker 5: Right.
• 28:35
  Speaker 3: So the British Navy wouldn't have to spend a lot
• 28:37
  Speaker 3: of money.
• 28:37
  Speaker 4: So.
• 28:38
  Speaker 3: The cure for scurvy is drink salt water. It's infinite.
• 28:43
  Speaker 3: That's not great. It's free.
• 28:46
  Speaker 2: And then another, like there was this observation that when
• 28:48
  Speaker 2: people get scurvy, they're like, they're lethargic and they slow down.
• 28:52
  Speaker 2: And so it was thought that like, no, this isn't
• 28:54
  Speaker 2: a symptom of scurvy setting in. This is you being
• 28:58
  Speaker 2: lazy and the laziness gives rise to scurvy. So if
• 29:02
  Speaker 2: you're feeling tired and lethargic, the solution is you need
• 29:06
  Speaker 2: to work harder and Which was not going to solve
• 29:09
  Speaker 2: the problem.
• 29:10
  Speaker 1: Why don't you just go jogging to cure your scurvy?
• 29:14
  Speaker 3: Yeah, right. Or your depression.
• 29:16
  Speaker 5: Right.
• 29:16
  Speaker 3: Now this is hitting home. So this is like in
• 29:20
  Speaker 3: the Wienersmith household.
• 29:21
  Speaker 2: But anyway, OK, so there were all of these bad treatments,
• 29:24
  Speaker 2: including things like mercury, which, you know, the English were
• 29:27
  Speaker 2: like slathering on everything for every reason you could imagine.
• 29:30
  Speaker 2: But James Lind in 1747 gets these 12 guys on
• 29:33
  Speaker 2: a ship that are starting to get scurvy.
• 29:35
  Speaker 1: Okay.
• 29:35
  Speaker 2: He puts them all in the same area, so they're
• 29:38
  Speaker 2: all in the same environment. He feeds them all the
• 29:41
  Speaker 2: exact same food. And then he splits them into six pairs.
• 29:45
  Speaker 2: And he gives each pair one of the prominent anti-scorbutics
• 29:51
  Speaker 2: or one of the prominent things that are used to
• 29:53
  Speaker 2: treat scurvy at the time.
• 29:55
  Speaker 1: So he's doing experiments on these guys.
• 29:57
  Speaker 2: Yes.
• 29:57
  Speaker 3: He's doing experiments on these guys. Right.
• 29:59
  Speaker 2: And so like two of the guys got spoonfuls of vinegar.
• 30:02
  Speaker 2: Two of the guys got seawater. Two of the guys
• 30:04
  Speaker 2: got oranges and a lemon. Two of the guys got cider.
• 30:09
  Speaker 2: And then two of them got like a medicinal paste
• 30:11
  Speaker 2: or something like that.
• 30:12
  Speaker 1: None of them had to like run laps or something?
• 30:15
  Speaker 3: No, not in this experiment.
• 30:17
  Speaker 1: They didn't just like get slapped and shouted at or something?
• 30:20
  Speaker 2: I mean, I think that's what was probably happening above
• 30:22
  Speaker 2: board where the ship's physician wasn't in charge of things.
• 30:27
  Speaker 1: Right. OK, so he did like a controlled experiment.
• 30:31
  Speaker 3: Yeah, right.
• 30:31
  Speaker 2: And the citrus treatment, those guys got totally better. And
• 30:34
  Speaker 2: it was clear that citrus was the solution. The guys
• 30:37
  Speaker 2: who had a quart of cider did OK because it
• 30:40
  Speaker 2: turns out there's some ascorbic acid in cider.
• 30:42
  Speaker 3: But there, like there was the answer, right?
• 30:44
  Speaker 1: So did the other guys die or did they give
• 30:47
  Speaker 1: them lemon juice in time?
• 30:48
  Speaker 3: History doesn't care.
• 30:54
  Speaker 2: I'm hoping that what happened is they ended up getting
• 30:55
  Speaker 2: oranges when the experiment was over.
• 30:57
  Speaker 5: Yeah.
• 30:58
  Speaker 1: Well, they gave their lives so we could understand scurvy.
• 31:01
  Speaker 1: Let's at least respect their sacrifice.
• 31:03
  Speaker 3: Oh, oh, oh, oh. This was not the moment where
• 31:06
  Speaker 3: everyone was like, oh, done. Citrus. That's the solution.
• 31:10
  Speaker 1: Oh, I see.
• 31:10
  Speaker 3: So he published it.
• 31:11
  Speaker 2: But when he published this account, he also talked smack
• 31:16
  Speaker 2: about everybody else who had bad ideas about what's caused
• 31:20
  Speaker 2: scurvy and how to treat it.
• 31:21
  Speaker 3: And so he ended up making a bunch of people
• 31:22
  Speaker 3: dislike him.
• 31:23
  Speaker 1: Oh, no.
• 31:25
  Speaker 2: And then he got put in charge of like a
• 31:26
  Speaker 2: naval hospital and his interest in doing good experiments like evaporated.
• 31:31
  Speaker 2: And from there on out, he started just like making
• 31:33
  Speaker 2: pronouncements about how to treat scurvy that were not backed
• 31:36
  Speaker 2: by scientific fact. And some of them strayed from this
• 31:39
  Speaker 2: citrus thing. And so the point is there were multiple
• 31:43
  Speaker 2: points in history where we were like on the right track.
• 31:46
  Speaker 2: And then we lost we you know, we lost the
• 31:49
  Speaker 2: the story there. But but now we know. It's ascorbic acid.
• 31:53
  Speaker 2: You can get it from fresh fruits and vegetables. This
• 31:56
  Speaker 2: can still be a problem. For example, refugee populations that
• 32:00
  Speaker 2: don't have access to a lot of fresh food, they
• 32:01
  Speaker 2: have to eat sort of whatever shelf-stable food they're given.
• 32:05
  Speaker 2: Sometimes scurvy is a problem for those populations. But thankfully
• 32:09
  Speaker 2: for most of us who can go to a grocery
• 32:11
  Speaker 2: store and can afford to buy fresh fruits and vegetables,
• 32:13
  Speaker 2: scurvy is something we shouldn't have to encounter.
• 32:15
  Speaker 1: Because some guy did crazy experiments and then retreated into
• 32:19
  Speaker 1: a life of feuds.
• 32:20
  Speaker 3: Well, that's scientist for you.
• 32:22
  Speaker 1: That's fascinating. And the stories of figuring it out are
• 32:25
  Speaker 1: always really compelling to me because it's never a straight line, right?
• 32:28
  Speaker 1: It's never like we did this experiment, the results were clear,
• 32:31
  Speaker 1: and then we knew. It's always like a hundred years later,
• 32:34
  Speaker 1: somebody looked at the data or somebody followed up or
• 32:37
  Speaker 1: somebody finally made sense of it. It's incredible how long
• 32:39
  Speaker 1: it takes to figure things out and how obvious things
• 32:42
  Speaker 1: seem to be in hindsight, right?
• 32:44
  Speaker 2: Yeah, but I feel like with scurvy in particular, it
• 32:46
  Speaker 2: makes sense to me that it was so confusing.
• 32:48
  Speaker 1: Yeah.
• 32:49
  Speaker 2: If the answer was oranges, I wouldn't have realized that like, oh,
• 32:52
  Speaker 2: cooking it in the copper pan first.
• 32:54
  Speaker 1: Mm-hmm.
• 32:54
  Speaker 3: Is going to totally inactivate the ascorbic acid like that.
• 32:57
  Speaker 3: I don't know.
• 32:58
  Speaker 2: That just doesn't even seem fair, even. That just seems
• 33:01
  Speaker 2: totally not fair.
• 33:02
  Speaker 1: Oh, wait.
• 33:04
  Speaker 2: And I haven't even told you the most interesting thing yet. Well,
• 33:07
  Speaker 2: how do you rank interesting?
• 33:08
  Speaker 3: I don't know.
• 33:09
  Speaker 2: But some species of primates and guinea pigs and us
• 33:12
  Speaker 2: are some of the few animals that can't produce vitamin
• 33:16
  Speaker 2: C on their own.
• 33:18
  Speaker 5: Oh.
• 33:19
  Speaker 2: So like rats that were on our ships weren't going
• 33:22
  Speaker 2: to get scurvy, even if there were no fruits and vegetables,
• 33:25
  Speaker 2: because their bodies are making their own vitamin C.
• 33:27
  Speaker 1: Why aren't we?
• 33:28
  Speaker 3: I don't know. I don't think I don't think we know.
• 33:31
  Speaker 2: I mean, it could be that like in our evolutionary past, we,
• 33:34
  Speaker 2: quote unquote, grew up in an area where there was
• 33:36
  Speaker 2: always fresh food around.
• 33:37
  Speaker 3: And so it just didn't come up. So we kind
• 33:38
  Speaker 3: of lost the ability.
• 33:39
  Speaker 2: And then we moved into environments where it turned out
• 33:41
  Speaker 2: it was much harder to get fresh fruits. And now
• 33:43
  Speaker 2: we're just not super well adapted anymore. But yeah, that
• 33:46
  Speaker 2: and guinea pigs and some scientists who were studying it
• 33:48
  Speaker 2: got really lucky that they were doing experiments on guinea
• 33:51
  Speaker 2: pigs who also happened to not make ascorbic acid because
• 33:54
  Speaker 2: some of the studies that we did were really like
• 33:56
  Speaker 2: nailed this stuff down were done in guinea pigs. And
• 33:59
  Speaker 2: if they had picked mice instead, it might have taken
• 34:01
  Speaker 2: us much longer to figure this stuff out. Yeah. Amazing. Well,
• 34:05
  Speaker 2: I collected stories for some other diseases, but I talked
• 34:07
  Speaker 2: so long about scurvy. I'm just going to tell you
• 34:10
  Speaker 2: that pellagra is caused by a deficiency of vitamin B3.
• 34:15
  Speaker 2: You can also get goiters if you don't have enough iodine,
• 34:19
  Speaker 2: rickets if you don't have enough vitamin D, and night
• 34:21
  Speaker 2: blindness if you don't have enough vitamin A. But the
• 34:23
  Speaker 2: good news is, for most of these, we have fortified
• 34:27
  Speaker 2: different foods that In the United States, for example. And
• 34:30
  Speaker 2: so if you just eat like a somewhat normal diet,
• 34:33
  Speaker 2: a lot of the foods are fortified so that you
• 34:35
  Speaker 2: will get enough of this. So, for example, the salt,
• 34:37
  Speaker 2: your table salt is usually fortified with iodine. So we
• 34:40
  Speaker 2: don't have to worry about things like goiters.
• 34:42
  Speaker 1: I remember when Katrina was pregnant and we discovered we'd
• 34:45
  Speaker 1: been using mostly kosher salt, which doesn't have iodine in it.
• 34:48
  Speaker 1: And we had a moment of panic that, you know,
• 34:51
  Speaker 1: our son was in utero without enough iodine. Of course,
• 34:55
  Speaker 1: he's fine.
• 34:57
  Speaker 3: What did you do?
• 34:58
  Speaker 1: We did a bunch of research and we discovered that, oh,
• 35:00
  Speaker 1: actually iodine is in lots of stuff and it's very
• 35:03
  Speaker 1: hard to avoid in modern society.
• 35:05
  Speaker 3: OK, good.
• 35:06
  Speaker 1: Even if you don't specifically put iodized salt on your
• 35:09
  Speaker 1: food at home.
• 35:10
  Speaker 2: Now, I know that you eat one meal a day
• 35:12
  Speaker 2: and it's dinner with your family. Does Katrina eat like
• 35:15
  Speaker 2: does she ever go to restaurants or something where she
• 35:17
  Speaker 2: would encounter table salts that happen to have iodine in it?
• 35:20
  Speaker 2: Or does she also only eat dinner made at home?
• 35:24
  Speaker 1: Katrina is not on the vampire diet. She eats like
• 35:27
  Speaker 1: a normal human being. And yes, eats out at restaurants.
• 35:30
  Speaker 1: And exactly, anytime you eat at somebody else's house or
• 35:32
  Speaker 1: in a restaurant or prepackaged foods or whatever, there's iodized
• 35:36
  Speaker 1: salt and everything. So we were worried and panicked because
• 35:39
  Speaker 1: we were new parents, but it was fine.
• 35:41
  Speaker 3: Oh, my gosh. The number of things I worried and
• 35:43
  Speaker 3: panicked about as a new parent.
• 35:46
  Speaker 1: Wow.
• 35:47
  Speaker 2: So, listener, universe clumpiness lover, did that address the question
• 35:51
  Speaker 2: that you forgot that you had? So I went a
• 35:53
  Speaker 2: little heavy on the history and a little light on
• 35:55
  Speaker 2: the collagen. I'm feeling like you would want it's more collagen.
• 35:58
  Speaker 3: But what are you going to do?
• 35:59
  Speaker 1: Thanks for taking my question, guys. Longtime listener. Love the show. Yes,
• 36:05
  Speaker 1: that totally answers my question. And I'm also disappointed, however.
• 36:09
  Speaker 1: that there were no goat sounds in the answer. That's
• 36:12
  Speaker 1: what I really was here for.
• 36:13
  Speaker 3: Okay, thank you.
• 36:18
  Speaker 2: I'm here to please. Let's take a break, and when
• 36:21
  Speaker 2: we come back, we will get to our third question.
• 36:43
  Speaker 2: And we're back, and we have a question from Jude
• 36:46
  Speaker 2: from Washington State.
• 36:47
  Speaker 4: Hi, Danielle and Kelly. Thanks for helping us get smarter
• 36:50
  Speaker 4: about this extraordinary universe. Given the chaotic factors that influence
• 36:55
  Speaker 4: the formation of Earth, it seems odd that a single
• 36:58
  Speaker 4: large landmass would develop with so much water on the
• 37:01
  Speaker 4: rest of the surface. Why would there be such a
• 37:04
  Speaker 4: bulge on one side of the planet? We weren't tidally locked,
• 37:08
  Speaker 4: were we? What do we know about that process? Thanks
• 37:12
  Speaker 4: for helping us learn. Jude from Washington State.
• 37:16
  Speaker 1: I love this question from Jude. It's so much fun.
• 37:19
  Speaker 1: I love that he's thinking about this history we've learned
• 37:23
  Speaker 1: about the planet and wondering how it all makes sense
• 37:26
  Speaker 1: and why it happens this way and bringing in other
• 37:29
  Speaker 1: ideas he's learned from physics. So this is exactly the
• 37:32
  Speaker 1: kind of curiosity I'd love to encourage in people. Thank you, Jude.
• 37:36
  Speaker 3: Yeah, this is a fantastic question.
• 37:37
  Speaker 2: I also love thinking about like Pangea and what the
• 37:40
  Speaker 2: Earth used to look like. And so can you start?
• 37:43
  Speaker 2: So it's so much easier when you have a picture
• 37:45
  Speaker 2: of Pangea. Help us picture, you know, what did our
• 37:48
  Speaker 2: planet look like 300 million years ago?
• 37:51
  Speaker 1: Well, like journeys into deep time are one of my
• 37:54
  Speaker 1: favorite things. Just imagining how much time has lapsed in
• 37:58
  Speaker 1: the universe that even really, really slow things can have
• 38:02
  Speaker 1: huge consequences over deep time. So for example- We know
• 38:06
  Speaker 1: the continents are moving, but it turns out that 335
• 38:10
  Speaker 1: million years ago, the arrangement of the continents on the
• 38:13
  Speaker 1: Earth was very, very different than it is today. Today,
• 38:17
  Speaker 1: you have the massive Pacific Ocean, but you have a
• 38:19
  Speaker 1: bunch of continents sort of spread out. But 335 million
• 38:23
  Speaker 1: years ago, we had a single continent. All the landmasses
• 38:26
  Speaker 1: were still there, but they were all clumped together into
• 38:30
  Speaker 1: one supercontinent called Pangea. And so if you took the
• 38:34
  Speaker 1: Earth and you spun it, it would be like mostly water.
• 38:37
  Speaker 1: And then there'd be like one slice of a bunch
• 38:40
  Speaker 1: of continents all stuck together, strung between the North Pole
• 38:44
  Speaker 1: and the South Pole, sort of like a big crescent.
• 38:47
  Speaker 1: And you can see like Proto-Africa and the beginnings of
• 38:51
  Speaker 1: Asia and stuff. And it forms like sort of a
• 38:54
  Speaker 1: sea shape where the top of the sea is near
• 38:56
  Speaker 1: the North Pole and the bottom of the sea is
• 38:58
  Speaker 1: near the South Pole.
• 38:59
  Speaker 2: So which– ocean one right so was it the pacific
• 39:03
  Speaker 2: ocean or the atlantic ocean which is the one that
• 39:05
  Speaker 2: gets to take all.
• 39:08
  Speaker 1: So it's a constant battle between the two oceans actually
• 39:11
  Speaker 1: the atlantic ocean doesn't exist at this time right so
• 39:15
  Speaker 1: pacific its formation is what broke up pangea so it's
• 39:19
  Speaker 1: like the rise of the atlantic ocean whoa but back
• 39:22
  Speaker 1: then they didn't call the pacific there was a super
• 39:25
  Speaker 1: ocean they call pantalassa i don't know who gets to
• 39:28
  Speaker 1: name all these things but they all sound really cool
• 39:30
  Speaker 1: and historical.
• 39:31
  Speaker 3: They're not physicists then.
• 39:32
  Speaker 1: Yeah. And the whole idea of super oceans comes from
• 39:37
  Speaker 1: the origin of the continental drift theory. So this is
• 39:40
  Speaker 1: like 100 years ago now. People are wondering about the
• 39:43
  Speaker 1: ancient history of the planet. And there's a long tradition
• 39:46
  Speaker 1: of being unable to to grapple with the times involved.
• 39:49
  Speaker 1: You know, like when we were learning about the age
• 39:52
  Speaker 1: of the Earth, people were like, maybe it's a million
• 39:54
  Speaker 1: years old. Oh my God, that would be so, maybe
• 39:56
  Speaker 1: it's 20 million. And then, you know, actually seeing the
• 40:00
  Speaker 1: evidence that it's almost 5 billion years old is just
• 40:03
  Speaker 1: mind blowing. And in the same way, the idea that
• 40:06
  Speaker 1: the continents are moving and they're moving very slowly so
• 40:09
  Speaker 1: that like you can't see anything basically over a lifetime,
• 40:13
  Speaker 1: but that over eons, it could totally change the face
• 40:16
  Speaker 1: of the planet. This is a very controversial idea about
• 40:19
  Speaker 1: 100 years ago. It took a long time before it
• 40:21
  Speaker 1: was adopted by mainstream science. And for that reason, it
• 40:25
  Speaker 1: plays an oversized role in both criticisms of science, like,
• 40:30
  Speaker 1: look how long it takes science to recognize the truth,
• 40:33
  Speaker 1: and also defenses of science, where people are like, well, actually,
• 40:37
  Speaker 1: it was the data that won out, and this is
• 40:40
  Speaker 1: how science is supposed to work. But not getting into
• 40:43
  Speaker 1: that whole culture war. Alfred Weniger- was the guy who
• 40:47
  Speaker 1: came up with this idea of continental drift in the
• 40:50
  Speaker 1: early 1900s. And he's the one who hypothesized the existence
• 40:54
  Speaker 1: of Pangea, sort of tracked all the continents motion backwards
• 40:59
  Speaker 1: in time and was able to predict like, oh, it
• 41:01
  Speaker 1: looks like they all came from one mega continent. And
• 41:05
  Speaker 1: it's not hard to imagine this if you just look
• 41:07
  Speaker 1: at like the Atlantic, right? You can look at the
• 41:10
  Speaker 1: coast of the United States and South America and and
• 41:13
  Speaker 1: see how like the coast of South America in particular
• 41:16
  Speaker 1: matches up with the coast of Africa, right? And the
• 41:19
  Speaker 1: Atlantic is getting wider every year. And so just reverse
• 41:22
  Speaker 1: that back in time and boom, South America and Africa
• 41:25
  Speaker 1: fit together very nicely into a mega continent. And there's
• 41:28
  Speaker 1: lots of really fun evidence for this. It's not just
• 41:31
  Speaker 1: continental drift. Like you can see the same mountain ranges
• 41:35
  Speaker 1: that are now on two different continents, but it's very
• 41:37
  Speaker 1: obvious geologically that they come from the same original mountain range.
• 41:41
  Speaker 1: like the Appalachians, right, in your area, you can see
• 41:45
  Speaker 1: the continuation of the Appalachians in Scandinavia. Like it's the
• 41:49
  Speaker 1: same mountains. Yes, I know. And you see evidence of fossils,
• 41:54
  Speaker 1: like animals that lived on one continent and then it's
• 41:57
  Speaker 1: split up and now we see fossils on both sides.
• 42:00
  Speaker 1: So it's very clear that continents are moving and they
• 42:03
  Speaker 1: used to be merged. And if you go back in time,
• 42:06
  Speaker 1: you can see this mega continent.
• 42:08
  Speaker 3: Do you think Alfred was into puzzles?
• 42:14
  Speaker 1: I think alfred must have had a really geometrical mind
• 42:17
  Speaker 1: yeah to think about all this stuff and and to
• 42:19
  Speaker 1: imagine what it must have looked like and so this
• 42:21
  Speaker 1: is the impetus of jude's question he's like how can
• 42:24
  Speaker 1: it be isn't it weird to have all the land
• 42:26
  Speaker 1: on one side and the rest is just water like
• 42:28
  Speaker 1: it feels imbalanced and he's wondering if this came from
• 42:31
  Speaker 1: like being tidally locked with the sun or something external
• 42:35
  Speaker 1: and so it's a great question And the answer is
• 42:38
  Speaker 1: super cool. The answer is that there's a cycle that
• 42:42
  Speaker 1: the Earth tends to build supercontinents and then break up
• 42:45
  Speaker 1: supercontinents and then build supercontinents and then break up supercontinents.
• 42:50
  Speaker 1: This has happened like several times in the last few
• 42:53
  Speaker 1: billion years. If you like had a movie of the
• 42:57
  Speaker 1: Earth over the last two billion years and you fast
• 42:59
  Speaker 1: forwarded it like super duper time lapse, you would see
• 43:02
  Speaker 1: supercontinents forming and breaking up and forming and breaking up.
• 43:06
  Speaker 3: Oh, that's scary. And so.
• 43:11
  Speaker 2: Thankfully it happens on very long timescales. So I'm going
• 43:14
  Speaker 2: to be honest. I think I've only I've mostly heard
• 43:16
  Speaker 2: about Pangea, the super continent. And I don't know that
• 43:19
  Speaker 2: I've heard about the like versions before that had been
• 43:23
  Speaker 2: broken up and then put back together.
• 43:25
  Speaker 3: First, let's talk about why. And then let's talk about
• 43:26
  Speaker 3: what came before. Why is that happening?
• 43:28
  Speaker 4: Yeah.
• 43:29
  Speaker 1: So there's two effects here, right? Why do continents come together?
• 43:33
  Speaker 1: Why does the earth tend to make super continents? And
• 43:36
  Speaker 1: then the other part is why does it tend to
• 43:37
  Speaker 1: break them up? So first, why does it make super continents? Well,
• 43:41
  Speaker 1: continents drift, right? What's happening is that the earth is
• 43:45
  Speaker 1: still hot and inside the earth, there's the mantle and
• 43:49
  Speaker 1: it's a really dense, hot rock, which effectively is like
• 43:52
  Speaker 1: a fluid, right? Not technically a liquid, but a fluid.
• 43:56
  Speaker 1: And so it flows and you get these convection cells,
• 43:59
  Speaker 1: where things rise and then sink, and so they're spinning.
• 44:03
  Speaker 1: And so you have these spinning cells underneath the hard crust,
• 44:07
  Speaker 1: and that's moving stuff. It's just like having a tank
• 44:11
  Speaker 1: tread underneath the tank. It's moving the tank. And so
• 44:14
  Speaker 1: it's sliding continental plates against each other And where they meet,
• 44:18
  Speaker 1: one of them gets pushed down back into the mantle.
• 44:21
  Speaker 1: It's a subduction zone. And it gets melted down, et cetera.
• 44:25
  Speaker 1: And so that's how continents move, right? Because these convection
• 44:28
  Speaker 1: cells are like pushing on things underneath. So what happens
• 44:32
  Speaker 1: if you have a bunch of continents and they start
• 44:34
  Speaker 1: out randomly distributed or whatever, and you just slide them
• 44:38
  Speaker 1: around the planet is eventually they're going to bang into
• 44:40
  Speaker 1: each other, right? And it's not like a box full
• 44:44
  Speaker 1: of balls that are going to bang into each other
• 44:46
  Speaker 1: and then bounce off. And so that on average, they're
• 44:49
  Speaker 1: going to stay separate. These things stick, right? They're subduction zones.
• 44:52
  Speaker 1: Things get pushed underneath. They get pushed against each other.
• 44:55
  Speaker 1: You get mountain ranges like Mount Everest, for example. And
• 44:59
  Speaker 1: so things stick together. And so it's like a box
• 45:02
  Speaker 1: of sticky balls. You shake it and they all bounce
• 45:05
  Speaker 1: around and eventually they all stick together and you get
• 45:07
  Speaker 1: one big ball, right?
• 45:08
  Speaker 3: Okay. But then how do you get them back out again?
• 45:10
  Speaker 1: Yeah. So that's what's happening. That's why you form supercontinents.
• 45:13
  Speaker 1: You have a bunch of continents. and they're wandering the planet,
• 45:16
  Speaker 1: they're going to end up hitting each other and sticking.
• 45:19
  Speaker 1: All right, so then why is it a cycle? Why
• 45:20
  Speaker 1: don't we just have one supercontinent forever, one to rule
• 45:24
  Speaker 1: them all, right? Well, the answer is that supercontinent formation
• 45:27
  Speaker 1: creates the process that breaks them up because you have
• 45:30
  Speaker 1: this heat underneath, right? But now you have a supercontinent,
• 45:34
  Speaker 1: and it's trapped all that heat. There's nowhere for it
• 45:36
  Speaker 1: to go, so it builds up. It makes like a
• 45:39
  Speaker 1: dome of heat underneath the supercontinent, and that creates a rift,
• 45:43
  Speaker 1: And that tears the supercontinent apart and it can create
• 45:46
  Speaker 1: like a new ocean. So the Atlantic Ocean, right, there's
• 45:49
  Speaker 1: the mid-Atlantic rift, which is like a tear in the
• 45:52
  Speaker 1: Earth's crust almost. And the Atlantic Ocean is expanding. It's
• 45:56
  Speaker 1: getting wider and wider every year. This is why South
• 45:59
  Speaker 1: America was torn from the coast of Africa. It's because
• 46:02
  Speaker 1: the Atlantic emerged and it's pushing those two apart. And
• 46:06
  Speaker 1: that's because there's a huge bubble of heat that was
• 46:09
  Speaker 1: trapped under there last time it was a supercontinent. And
• 46:12
  Speaker 1: so super continents form, they create these heat domes because
• 46:16
  Speaker 1: there's nowhere for this heat to get released. And then
• 46:18
  Speaker 1: it pulls them apart. And that's how the Atlantic ocean
• 46:21
  Speaker 1: was created. And so this has happened several times in
• 46:25
  Speaker 1: the history of the planet and probably will continue to happen.
• 46:29
  Speaker 3: But we won't be seeing it because we won't be
• 46:31
  Speaker 3: living long enough.
• 46:33
  Speaker 1: Because we're on an imminent decline to a nursing home.
• 46:36
  Speaker 3: And apparently about two years, according to Daniel.
• 46:40
  Speaker 2: So what are some of the cool names that obviously
• 46:42
  Speaker 2: were not made by physicists that these super continents had before?
• 46:47
  Speaker 1: So a lot of this is speculative because you're projecting
• 46:50
  Speaker 1: back many collisions, and it's very chaotic, and we don't
• 46:54
  Speaker 1: have clear data in some cases. But we also do
• 46:56
  Speaker 1: have some data, right? Big geological effects like this leave
• 47:00
  Speaker 1: markers all over the planet, and geologists are very, very
• 47:02
  Speaker 1: clever in extracting these clues. So we think that around
• 47:05
  Speaker 1: 2 billion years ago, there was a supercontinent called Columbia
• 47:10
  Speaker 1: that lasted about 200 million years. That's a long time.
• 47:15
  Speaker 1: Then it got torn apart. And continents wandered the planet
• 47:18
  Speaker 1: for about 500 million years until they formed another supercontinent
• 47:23
  Speaker 1: called Rodinia. So this is 1.3 billion years ago. And
• 47:28
  Speaker 1: this one lasted for half a billion years before things
• 47:31
  Speaker 1: wandered again. Then they came together around 540 million years
• 47:35
  Speaker 1: ago to make another supercontinent called Panotia. That one didn't
• 47:39
  Speaker 1: last for very long. It broke apart. And then Pangaea
• 47:42
  Speaker 1: was formed around 350 million years ago. So it's fun
• 47:46
  Speaker 1: to think about that history and to overlay onto it
• 47:49
  Speaker 1: the history of life on Earth, right? Because the Cambrian
• 47:52
  Speaker 1: explosion is less than a billion years ago. The dinosaurs, right,
• 47:56
  Speaker 1: overlap with this. So the configuration of the continents played
• 48:01
  Speaker 1: a big role in where critters were, which ones were
• 48:04
  Speaker 1: connected to which other ones. If you lived a long
• 48:07
  Speaker 1: time ago, you saw a different planet than the one
• 48:10
  Speaker 1: we have today. Our Earth, what you think makes it Earth,
• 48:14
  Speaker 1: is actually just a momentary snapshot in the life of
• 48:18
  Speaker 1: a very dynamic planet.
• 48:19
  Speaker 2: Man, it really blows my mind that geologists were able
• 48:22
  Speaker 2: to figure all of this out.
• 48:24
  Speaker 3: This is really cool.
• 48:26
  Speaker 1: And that the story is interesting, right? You could look
• 48:29
  Speaker 1: back on the history of the planet and be like, oh, yeah,
• 48:31
  Speaker 1: it was made this way. And it's always been this way. Yawn.
• 48:34
  Speaker 1: But instead, it's like super chaotic and dynamic. There's all
• 48:37
  Speaker 1: sorts of stuff happening. It's incredible. I'm really glad that
• 48:40
  Speaker 1: geology didn't turn out to be boring.
• 48:43
  Speaker 3: I don't know.
• 48:43
  Speaker 2: From a biologist perspective, at least yawn means you're like
• 48:47
  Speaker 2: not as likely to die from something catastrophic.
• 48:49
  Speaker 3: But I see your point. This is a more interesting story.
• 48:53
  Speaker 1: It's funny how sometimes boring is good and sometimes it's not.
• 48:56
  Speaker 1: Like one of my kids had an MRI one time.
• 48:59
  Speaker 1: And I'll always remember that the conclusion was MRI is unremarkable.
• 49:04
  Speaker 1: And I was like, that's good news, I think, from
• 49:07
  Speaker 1: like a health point of view, that there's nothing weird
• 49:10
  Speaker 1: in your MRI. But I was like, actually, this kid's
• 49:12
  Speaker 1: pretty remarkable. So, you know, I'm going to try not
• 49:14
  Speaker 1: to be insulted.
• 49:15
  Speaker 2: I know.
• 49:16
  Speaker 3: He is a very remarkable kid.
• 49:18
  Speaker 2: But yes, there are some things you want to be
• 49:20
  Speaker 2: unremarkable and your medical results are certainly some of them.
• 49:24
  Speaker 1: Yes, exactly.
• 49:26
  Speaker 5: All right.
• 49:26
  Speaker 1: Well, thank you, Jude, for this wonderful question. We're going
• 49:29
  Speaker 1: to send this back to you to hear if we've
• 49:30
  Speaker 1: answered your question and if you have any follow-ups.
• 49:33
  Speaker 4: Well, that was great. First, I've been mispronouncing Pangea. Now
• 49:39
  Speaker 4: I see it. Sticky continents that combine and split and recombine?
• 49:43
  Speaker 1: Huh.
• 49:44
  Speaker 5: Amazing.
• 49:46
  Speaker 4: I thought having one supercontinent was impressive. Now I picture
• 49:50
  Speaker 4: the Earth as this sloshy blob swirling its way around
• 49:53
  Speaker 4: the Sun. So much for being rock solid and terra firma.
• 49:57
  Speaker 4: Does this suggest the Earth is mostly liquid? Well, very hot,
• 50:01
  Speaker 4: slow-moving liquid? Thanks for helping us learn and changing our
• 50:05
  Speaker 4: perspectives in this sloshy, messy, complicated universe.
• 50:09
  Speaker 3: All right.
• 50:09
  Speaker 2: Thank you so much for these amazing questions. I have
• 50:12
  Speaker 2: a little bit of bad news and my bad news
• 50:14
  Speaker 2: is I need to take a little bit of an
• 50:16
  Speaker 2: email hiatus because I have a six month backlog on
• 50:18
  Speaker 2: questions I haven't answered yet.
• 50:20
  Speaker 1: Wow.
• 50:20
  Speaker 2: You know, and Daniel took two years to get his answer.
• 50:22
  Speaker 2: It just kind of happened to be that I was
• 50:24
  Speaker 2: reading about scurvy today and was like, oh, I can
• 50:26
  Speaker 2: answer Daniel's question. So I can't do any new research questions.
• 50:30
  Speaker 2: I'll tell you at some point in 2027 when I'm
• 50:32
  Speaker 2: able to take some new ones. But I need to
• 50:34
  Speaker 2: get through the amazing questions that you all have already
• 50:37
  Speaker 2: asked me. And I have many fun hours of research ahead.
• 50:40
  Speaker 2: But I look forward to when I can take more questions.
• 50:42
  Speaker 1: All right. Well, thank you very much, everyone, for sharing
• 50:44
  Speaker 1: with us your curiosity. It's what we thrive on.
• 50:48
  Speaker 3: Until next time.
• 50:55
  Speaker 1: Thanks, everybody, for listening. Please go and do us a
• 50:58
  Speaker 1: favor and rate the show on whatever podcast app you're using.
• 51:01
  Speaker 1: It really helps people find us.
• 51:03
  Speaker 2: Daniel and Kelly's Extraordinary Universe is edited by the amazing
• 51:07
  Speaker 2: Matt Kesselman.
• 51:08
  Speaker 1: He really is a wizard. You can also find us
• 51:12
  Speaker 1: online on Blue Sky, Instagram, and XDNK Universe. Come engage
• 51:18
  Speaker 1: with us.
• 51:18
  Speaker 2: You can email us at questions at danielandkelly.org. We really
• 51:22
  Speaker 2: do want to hear from you.
• 51:24
  Speaker 1: And you can find our website, www.danielandkelly.org, where you'll also
• 51:29
  Speaker 1: find an invitation to join our Discord, where everybody comes
• 51:32
  Speaker 1: and talks about the amazing universe.
• 51:35
  Speaker 2: And we also have the most amazing moderators. This is
• 51:39
  Speaker 2: an iHeart Podcast. Thanks for joining us.