Latest / Daniel and Kelly’s Extraordinary Universe / Listener Questions #45

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Listener Questions #45 · Daniel and Kelly’s Extraordinary Universe

• 0:07
  Speaker 1: How would a supervillain get Jupiter to Bleau? Not that
• 0:11
  Speaker 1: anyone wants to, but would it make a great show?
• 0:15
  Speaker 2: Norwegian kids are often born blonde but end up brunette.
• 0:19
  Speaker 2: Why did this help our Viking ancestors fend off some threat?
• 0:24
  Speaker 1: Imagine aliens on a planet without iron to find? Could
• 0:28
  Speaker 1: they still discover magnets and send us messages from their
• 0:31
  Speaker 1: alien minds?
• 0:33
  Speaker 2: Ooh, whatever questions keep you up at night, Daniel and
• 0:37
  Speaker 2: Kelly's answers will make it right.
• 0:39
  Speaker 1: Welcome to listener questions number forty five on Daniel and
• 0:43
  Speaker 1: Kelly's Extraordinary Universe.
• 0:58
  Speaker 3: Hello, I'm Kelly Winners.
• 1:00
  Speaker 2: I study parasites and space, and I am getting a
• 1:02
  Speaker 2: little bit concerned at all of the questions we get
• 1:05
  Speaker 2: from our listeners that suggest they're researching how to become supervillains.
• 1:12
  Speaker 1: Hi. I'm Daniel. I'm a particle physicist who loves thinking
• 1:15
  Speaker 1: about aliens, and I'm happy to grow the supervillain demographic
• 1:19
  Speaker 1: in our audience.
• 1:20
  Speaker 2: And you are, And so, Daniel, give them something to
• 1:23
  Speaker 2: work with. If you were going to be a supervillain,
• 1:26
  Speaker 2: what would you do with your physics or cosmology knowledge
• 1:31
  Speaker 2: to do the most supervillainy thing you can think of.
• 1:34
  Speaker 1: I think I've advertised this on the show already. I
• 1:37
  Speaker 1: would gamble or trade away the entire Earth to super
• 1:40
  Speaker 1: intelligent aliens if they could offer us some insight into
• 1:44
  Speaker 1: the deepest questions of the universe.
• 1:46
  Speaker 2: Oh that's that's supervillainy for sure. And we all knew
• 1:49
  Speaker 2: that you valued the aliens you've never met much more
• 1:52
  Speaker 2: than ever human on this planet. But I'm talking about like,
• 1:55
  Speaker 2: you know, would you push Jupiter into the Earth or
• 1:59
  Speaker 2: or you just you have very tunnel vision on this
• 2:02
  Speaker 2: alien thing.
• 2:03
  Speaker 1: Wow, you really want me to be a supervillain here?
• 2:05
  Speaker 4: Huh?
• 2:06
  Speaker 3: I mean, I'm giving the people what they want.
• 2:08
  Speaker 1: I would similarly encourage people to do experiments here on
• 2:12
  Speaker 1: Earth and might even risk the planet. Like when we
• 2:15
  Speaker 1: turned down the large hade On collider, there was a
• 2:17
  Speaker 1: big brujha about is it going to make black holes
• 2:20
  Speaker 1: the gobble of the Earth, And no, the answer is
• 2:23
  Speaker 1: it's not going to There are higher energy collisions happening
• 2:26
  Speaker 1: all the time in the atmosphere anyway, They're not destroying
• 2:28
  Speaker 1: the Earth. But in my view, actually I didn't really
• 2:31
  Speaker 1: care what even if it was going to risk the
• 2:33
  Speaker 1: Earth and maybe create a black hole to gobble everything.
• 2:36
  Speaker 1: I was like, let's do it, because that would be
• 2:39
  Speaker 1: fascinating this.
• 2:41
  Speaker 2: You know what, I shouldn't ask you these questions because
• 2:44
  Speaker 2: I'm always disappointed afterwards.
• 2:46
  Speaker 1: I tried to squirrel away from it.
• 2:48
  Speaker 2: You do, Okay, let's move on. Let's go ahead and
• 2:52
  Speaker 2: hear Kenny's question about Jupiter. Kenny is today's supervillain.
• 2:56
  Speaker 5: Listener, Hi, Daniel, you are talking about Jeep and then
• 3:00
  Speaker 5: we fall off something a bit scary.
• 3:03
  Speaker 6: Stupiter is the main most of hydroen for quoditics. Blow.
• 3:09
  Speaker 6: What if evil space ladens.
• 3:11
  Speaker 5: A vager with a plan to destroys the Solder sister
• 3:15
  Speaker 5: watch flat them to use huge amounts of oxygen onto
• 3:20
  Speaker 5: use make a giant explosive or waffully to what's in
• 3:24
  Speaker 5: loads of banandas and jack chocolate making JEP to heavy
• 3:28
  Speaker 5: and heavy into it turns into at what's what's happened
• 3:31
  Speaker 5: to Earth? Where the Earth get blasted apart? But will
• 3:36
  Speaker 5: happen instantly? Oh?
• 3:38
  Speaker 6: What can I attend? Find new standing a scale that
• 3:42
  Speaker 6: stays there for a really long time?
• 3:45
  Speaker 3: Wow, Kenny, what are you planning?
• 3:47
  Speaker 7: Man?
• 3:51
  Speaker 1: Well? Kenny does really seem like he's got big plans,
• 3:58
  Speaker 1: and unfortunately, we're not going to suggest anything that's of
• 4:02
  Speaker 1: any practical use to him.
• 4:04
  Speaker 3: So that's good. That's good.
• 4:07
  Speaker 1: Essentially, there are two ways for Kenny's dreams to become reality,
• 4:11
  Speaker 1: via physics or via chemistry. I don't see any biological
• 4:15
  Speaker 1: way to destroy Jupiter, so we're limited to those two
• 4:18
  Speaker 1: basic sciences.
• 4:19
  Speaker 3: I feel like this is one of the reasons why
• 4:20
  Speaker 3: biology is great.
• 4:21
  Speaker 1: But all right, go on, all right, So let's talk
• 4:24
  Speaker 1: about destroying Jupiter via physics. What that means essentially is fusion.
• 4:29
  Speaker 1: This is what's already happening at the core of stars.
• 4:33
  Speaker 1: You have a huge ball of gas, mostly hydrogen. It
• 4:36
  Speaker 1: gets compressed due to gravity that increases the temperature and
• 4:40
  Speaker 1: the pressure, and eventually you have such high temperature and
• 4:43
  Speaker 1: pressure that fusion goes from essentially impossible never never happens
• 4:46
  Speaker 1: to very rarely happens, but happens often enough to release
• 4:50
  Speaker 1: enough heat to increase the chances of fusion, or to
• 4:54
  Speaker 1: at least maintain it. So the thing to understand here
• 4:56
  Speaker 1: is that fusion is very sensitive in a nonlinear way
• 4:59
  Speaker 1: to pressure and temperature. You double the pressure and temperature
• 5:03
  Speaker 1: the race of fusion don't go up by two, they
• 5:05
  Speaker 1: go by more than two. It's nonlinear and so really
• 5:09
  Speaker 1: big stars, for example, have a lot of gravity, they
• 5:12
  Speaker 1: get really hot, fusion goes really fast, and big stars
• 5:16
  Speaker 1: burn themselves really quickly. Small stars have less pressure and temperature.
• 5:21
  Speaker 1: Fusion at their heart goes very slowly. They can last
• 5:24
  Speaker 1: for billions and billions, maybe even trillions of years. So
• 5:28
  Speaker 1: the amount of stuff you have determines the pressure and temperature,
• 5:32
  Speaker 1: which determines how much fusion is happening.
• 5:35
  Speaker 2: But I feel like fizzling out is very different than exploding,
• 5:40
  Speaker 2: which is what Kenny's Are we going to get to?
• 5:42
  Speaker 3: The explosions is what I'm wondering, Daniel, When do happen?
• 5:47
  Speaker 1: You want some more kabooms? I mean, if the star
• 5:51
  Speaker 1: is big enough and hot enough, then it will blow
• 5:53
  Speaker 1: itself apart. Okay, Like if you try to make a
• 5:56
  Speaker 1: star that's more than three hundred times the mass of
• 5:58
  Speaker 1: the Sun, you just can't do it because it's so big,
• 6:02
  Speaker 1: it gets so hot, the fusion is so powerful that
• 6:05
  Speaker 1: it blows itself apart, and you end up with a
• 6:06
  Speaker 1: star of mass around three hundred times the mass of
• 6:09
  Speaker 1: the Sun. Because most stars are a balance between gravity
• 6:14
  Speaker 1: and the fusion pressure the energy that's being released by
• 6:17
  Speaker 1: that fusion, and so when it gets too big, then
• 6:20
  Speaker 1: gravity makes it too hot, and then the pressure and
• 6:22
  Speaker 1: temperature get cranked up and then fusion winds. So in
• 6:26
  Speaker 1: order to make Jupiter really blow, you'd need it to
• 6:29
  Speaker 1: be three hundred times the mass of the Sun, and
• 6:32
  Speaker 1: currently it's about one thousands the mass of the Sun. Really,
• 6:36
  Speaker 1: and so you look confused.
• 6:37
  Speaker 3: No, I'm not confused. I'm surprised, they guess.
• 6:39
  Speaker 2: I'd assume Jupiter had a lot more mass, but the
• 6:42
  Speaker 2: Sun is that much more massy.
• 6:44
  Speaker 1: Huh oh, yeah, I mean the Solar system is basically
• 6:47
  Speaker 1: the Sun. Everything else is a crumb. We have a
• 6:50
  Speaker 1: totally distorted view of the Solar System because we live
• 6:52
  Speaker 1: on a planet, so we think it's really important. It's
• 6:55
  Speaker 1: like if you live in a tiny town outside New
• 6:57
  Speaker 1: York City and you think that it's also appear on
• 7:00
  Speaker 1: a map, when really it's just New York City. You know,
• 7:03
  Speaker 1: we're basically irrelevant. We're irrelevant compared to Jupiter. Jupiter is
• 7:07
  Speaker 1: basically irrelevant compared to the Sun, so we're irrelevant squared.
• 7:11
  Speaker 1: Oh no, yeah, So what this means is that Kenny
• 7:13
  Speaker 1: has a lot of work to do. There's a few
• 7:15
  Speaker 1: thresholds here, like what would it take to get fusion
• 7:19
  Speaker 1: happen at all in Jupiter. People sometimes imagine this is
• 7:22
  Speaker 1: like an on off switch. There is fusion happening within Jupiter,
• 7:25
  Speaker 1: it's just very rarely and not enough to do anything interesting.
• 7:29
  Speaker 1: For fusion to get like hot enough, so you start
• 7:32
  Speaker 1: to increase the temperature of Jupiter further. To be ignitioned,
• 7:35
  Speaker 1: it need to be about eighty times its current mass.
• 7:38
  Speaker 1: It's like the minimum size for a star to really glow.
• 7:42
  Speaker 1: They would become like a really dim red dwarf, so
• 7:45
  Speaker 1: not a boom an explosion, just like a very very
• 7:49
  Speaker 1: gentle star. As you add mass, it gets brighter and brighter.
• 7:52
  Speaker 1: You get up to the mass of the Sun, which
• 7:54
  Speaker 1: is a slightly above average star, and then you could
• 7:57
  Speaker 1: keep going to get up to the most massive stars
• 7:59
  Speaker 1: in the universe, but it would take an enormous amount
• 8:01
  Speaker 1: of mass, Like there isn't enough mass in the Solar
• 8:04
  Speaker 1: system obviously, to make another star that's three hundred times
• 8:07
  Speaker 1: the mass of the Sun. You'd need to like gather
• 8:09
  Speaker 1: three hundred neighboring solar systems and squeeze all of their
• 8:13
  Speaker 1: mass into Jupiter, then get a really awesome explosion.
• 8:16
  Speaker 3: You better be a very motivated supervillain. That's a lot
• 8:19
  Speaker 3: of work.
• 8:20
  Speaker 1: More realistically, if he gets enough bananas and dark chocolate
• 8:24
  Speaker 1: like siphons off some mass from the Sun and dumps
• 8:27
  Speaker 1: it into Jupiter, he could get Jupiter to ignite into
• 8:30
  Speaker 1: a star if he cranks up its mass by a
• 8:32
  Speaker 1: factor of eighty, so we're talking eighty jupiters squeeze together, right,
• 8:37
  Speaker 1: then you're gonna get a very dim red dwarf that
• 8:40
  Speaker 1: would warm Earth a little bit. Like Jupiter's kind of
• 8:42
  Speaker 1: far away. It's much further from Earth than the Sun is,
• 8:45
  Speaker 1: and a red dwarf would be much much dimmer, but
• 8:48
  Speaker 1: it would have some impact on the Earth. It would
• 8:50
  Speaker 1: also affect the Earth's orbit. Earth's orbit is not just
• 8:53
  Speaker 1: determined by the Sun. Jupiter does play a role. There's
• 8:56
  Speaker 1: a reason we have like ice ages and all sorts
• 8:58
  Speaker 1: of long terms cycles because Earth is getting tweaked by
• 9:02
  Speaker 1: the other planets. It's a little bit of a chaotic system.
• 9:05
  Speaker 1: These are called Melankovitch cycles. And so if Jupiter becomes
• 9:08
  Speaker 1: eighty times it's mass that's going to get more dramatic.
• 9:12
  Speaker 2: All right, do we have anything that's more boomy though
• 9:15
  Speaker 2: that we could give him as an answer?
• 9:17
  Speaker 3: Is there something else we could do?
• 9:19
  Speaker 1: Chemistry is definitely more boomy than physics in this scenario.
• 9:22
  Speaker 1: I mean physics, and fusion is behind, like you know,
• 9:25
  Speaker 1: atomic bombs, fusion bombs. So that's pretty dramatic. Yeah, but
• 9:28
  Speaker 1: it's hard to get that kind of density. But you
• 9:30
  Speaker 1: could also do it with chemistry, right, Like you know,
• 9:33
  Speaker 1: hydrogen famously burns, but what is burning burning is a
• 9:37
  Speaker 1: chemical reaction. It's combustion. You take something like hydrogen and
• 9:41
  Speaker 1: oxygen and you add a spark and then you get
• 9:44
  Speaker 1: water and energy. Famously, the Hinden bird is hydrogen burning. Right.
• 9:50
  Speaker 1: This is why we don't fill in massive tanks with
• 9:53
  Speaker 1: hydrogen anymore, because hydrogen and oxygen combust Oh, the humanity.
• 9:57
  Speaker 3: It's a little surprising.
• 9:59
  Speaker 2: We thought it was a good I initially, but we
• 10:02
  Speaker 2: don't do it anymore.
• 10:03
  Speaker 1: And if you are on a massive hydrogen filled balloon,
• 10:07
  Speaker 1: don't go out onto the smoking deck. It's not a
• 10:09
  Speaker 1: good idea.
• 10:10
  Speaker 3: No, no, actually, don't smoke.
• 10:13
  Speaker 1: Yes, don't smoke at all.
• 10:14
  Speaker 3: Filigious recommendation.
• 10:17
  Speaker 1: And something I very rarely say, is that this little
• 10:20
  Speaker 1: bit of chemistry is actually kind of interesting because you
• 10:23
  Speaker 1: see oxygen a lot. It's around all the time, you
• 10:27
  Speaker 1: see it in combustion, you see it in lots of reactions.
• 10:30
  Speaker 1: It's also important in biochemistry, right. Oxygen is an electron acceptor.
• 10:34
  Speaker 1: It's important for metabolism. We breathe in oxygen via our
• 10:38
  Speaker 1: lungs because we need it, and it's all for the
• 10:41
  Speaker 1: same reason. Is that oxygen has openings for electrons in
• 10:45
  Speaker 1: a fairly low energy state, and so what you're trying
• 10:48
  Speaker 1: to do in all of these reactions is release energy.
• 10:51
  Speaker 1: And so for that to happen, you need to take
• 10:52
  Speaker 1: something at a high energy level and get it to
• 10:54
  Speaker 1: a lower energy level. So when biochemists talk about electron acceptors,
• 10:59
  Speaker 1: what they mean is basically, there's a valley here. So
• 11:01
  Speaker 1: if you have rocks on the tops of hills, you
• 11:03
  Speaker 1: can roll them down into this valley and then you
• 11:06
  Speaker 1: can gather that energy. If you have rocks on the
• 11:08
  Speaker 1: top of hills, but it's just hills and there's no valleys,
• 11:10
  Speaker 1: there's nowhere for that energy to go, and so you
• 11:14
  Speaker 1: need valleys. And oxygen is basically a value which is
• 11:16
  Speaker 1: a way to release energy. All right, So let's say
• 11:19
  Speaker 1: that Kenny wants to blow up Jupiter with chemistry. How
• 11:23
  Speaker 1: much oxygen does he need? Well a lot. Jupiter is
• 11:28
  Speaker 1: about ten to twenty seven kilograms. About seventy five percent
• 11:32
  Speaker 1: of that is hydrogen, so call that like one times
• 11:36
  Speaker 1: ten to twenty seven kilograms. Oxygen is much more massive
• 11:40
  Speaker 1: than hydrogen. Remember that hydrogen is atomic element number one.
• 11:44
  Speaker 1: It's just a proton. Oxygen is eight protons, right, so
• 11:48
  Speaker 1: it's eight times more mass. So if you want to
• 11:51
  Speaker 1: do the chemical reaction of like H two plus O two,
• 11:55
  Speaker 1: then four grams of hydrogen means thirty two grams of
• 11:59
  Speaker 1: oxygen eight times as much. So you want to blow
• 12:03
  Speaker 1: up all of Jupiter, you're gonna need like six times
• 12:07
  Speaker 1: the mass of Jupiter in oxygen to make that combustion happen.
• 12:12
  Speaker 1: We're talking eighteen hundred times the mass of the Earth,
• 12:16
  Speaker 1: all in oxygen, which you gotta find somewhere, Kenny.
• 12:18
  Speaker 2: Yeah, So this is a very common misconception about supervillains.
• 12:21
  Speaker 2: They're not just lazy misanthropes. You gotta work hard to
• 12:24
  Speaker 2: be a supervillain.
• 12:26
  Speaker 1: And you gotta have connects. Do you have an oxygen guy? Kenny,
• 12:30
  Speaker 1: because you're gonna need one.
• 12:31
  Speaker 3: That's right.
• 12:31
  Speaker 2: Networking is critical, kay, exactly, get on LinkedIn exactly.
• 12:37
  Speaker 1: And you can't just mix hydrogen and oxygen right because
• 12:41
  Speaker 1: though this reaction is energetically favorable, like it does release energy,
• 12:44
  Speaker 1: there's an activation barrier here. So you're not just like
• 12:47
  Speaker 1: at the top of a hill rolling down the rock.
• 12:51
  Speaker 1: You're in a little valley at the top of the hill,
• 12:53
  Speaker 1: and you've got to get over the edge of the
• 12:54
  Speaker 1: volcano and then down into the valley. So that's why
• 12:58
  Speaker 1: you need a spark. You just mix that gene oxygen,
• 13:00
  Speaker 1: you don't get the reaction. You need to light a match,
• 13:03
  Speaker 1: and that initial energy gets it going, and then the
• 13:06
  Speaker 1: heat released by the combustion gets it going. It's what
• 13:09
  Speaker 1: we call ignition. Now that's not a problem in Jupiter.
• 13:12
  Speaker 1: You don't need a match, Kenny, because the core of
• 13:14
  Speaker 1: Jupiter is already very, very hot. The challenge here is mixing.
• 13:18
  Speaker 1: You need enough oxygen mixing with hydrogen in an even way,
• 13:23
  Speaker 1: and oxygen is heavier than helium. So if you just
• 13:26
  Speaker 1: dump it into Jupiter from your spaceship, it's gonna all
• 13:29
  Speaker 1: sync to the core. You're not going to get like
• 13:31
  Speaker 1: a smooth combustion. So probably what you're going to get
• 13:35
  Speaker 1: is like a series of planet wide explosions rather than
• 13:39
  Speaker 1: like a single boom. There's gonna be turbulence in the combination.
• 13:42
  Speaker 1: You're gonna get like atmospheric detonation fronts. A lot of
• 13:46
  Speaker 1: the heat is going to get reabsorbed, just heating up
• 13:49
  Speaker 1: the gas and expanding it, so you're gonna get huge
• 13:52
  Speaker 1: plasma shells. We actually got to see in history a
• 13:56
  Speaker 1: bunch of cool explosions in the atmosphere of Jupiter when
• 13:59
  Speaker 1: a it struck Jupiter in nineteen ninety four and we
• 14:03
  Speaker 1: saw massive fireballs, like bigger than the Earth, which was
• 14:06
  Speaker 1: really awesome, and.
• 14:07
  Speaker 3: You got to watch I remember this story.
• 14:10
  Speaker 1: It did, get to watch it. Yeah, it was a
• 14:12
  Speaker 1: cool summer for me.
• 14:13
  Speaker 3: Yeah.
• 14:14
  Speaker 1: And this would release a huge amount of energy, you know,
• 14:17
  Speaker 1: it would release probably like ten to the eight jewels
• 14:20
  Speaker 1: per kilogram. That's a lot of energy, probably two times
• 14:25
  Speaker 1: ten to thirty five jewels in total, that's like ten
• 14:29
  Speaker 1: to the eighteen that's like a quintillion sar bombas wow, right,
• 14:34
  Speaker 1: or like sixteen times the annual solar output all in
• 14:38
  Speaker 1: one explosion. So it would be dramatic. We would definitely
• 14:42
  Speaker 1: see it here on Earth. We would probably get sunburns.
• 14:46
  Speaker 1: It might fry us, but I think there's some technical
• 14:49
  Speaker 1: challenges there that I doubt Kenny's going to overcome, so
• 14:51
  Speaker 1: I'm not shy to give him all this advice.
• 14:54
  Speaker 3: You don't know, Kenny Man, Kenny, it might be a
• 14:57
  Speaker 3: real go getter.
• 14:58
  Speaker 1: This could be the beginning of Kenny story. Let's find
• 15:00
  Speaker 1: out that's right.
• 15:01
  Speaker 3: And Kenny, if you have any follow up questions for Daniel,
• 15:04
  Speaker 3: let us know.
• 15:06
  Speaker 6: Thank you finding my question on your POLCCAT. I like
• 15:10
  Speaker 6: the atmosphere designated foots on that. Who has a forecast?
• 15:34
  Speaker 1: Okay, we're back and transitioning from answering questions from potential
• 15:37
  Speaker 1: super villains to helping people understand their children's hair, which.
• 15:42
  Speaker 3: Is a tough question.
• 15:43
  Speaker 2: And so all right, we are going to hear two
• 15:46
  Speaker 2: questions from listeners because I got a very similar question
• 15:49
  Speaker 2: from two different folks, and so let's hear Mark and
• 15:52
  Speaker 2: Ephraim's questions about what the heck is going on with
• 15:55
  Speaker 2: their kids' heads.
• 15:56
  Speaker 7: Hi, Daniel and Kelly, this is Ephraim from Arlington, Massachusetts.
• 16:00
  Speaker 7: I just listened to the discussion of Gray hair and
• 16:03
  Speaker 7: listener questions number twenty nine, which totally overturned what I
• 16:07
  Speaker 7: previously read about how gray hair works. Kelly's mention of
• 16:11
  Speaker 7: hair follicles lasting four to six years made me wonder
• 16:14
  Speaker 7: if the same turnover in the follicle population relates to
• 16:18
  Speaker 7: how some children's hair color changes. I was blonde as
• 16:22
  Speaker 7: a very young child up to about age five, and
• 16:25
  Speaker 7: brown haired ever since, well except for the red in
• 16:28
  Speaker 7: my beard, which has now gone gray. My number one
• 16:32
  Speaker 7: son did roughly the same thing, though his blonde hair
• 16:35
  Speaker 7: lasted perhaps a year longer than mine.
• 16:37
  Speaker 4: Hand Hello, Kelly and Dan. In my little Norwegian town
• 16:42
  Speaker 4: in southern Wisconsin, we have all these little children who
• 16:45
  Speaker 4: start out with whitish blonde hair, including my kids, by
• 16:49
  Speaker 4: the time they are in high school at brown hair.
• 16:52
  Speaker 4: Does this have to do with the six year cycle
• 16:54
  Speaker 4: of a hair follicle? What evolutionary advantage would changing hair
• 16:58
  Speaker 4: color have had? And Hunter Gatherers Scandinavia, thank you, Mark.
• 17:04
  Speaker 2: Can I start with a funny story about my son's
• 17:07
  Speaker 2: hair color?
• 17:08
  Speaker 1: Ooh, yes, tell us what is your son's hair color
• 17:10
  Speaker 1: and why is it hilarious?
• 17:11
  Speaker 6: Well?
• 17:11
  Speaker 2: Okay, well, so he was originally born with really dark
• 17:14
  Speaker 2: hair like the color of mind before I started going gray.
• 17:17
  Speaker 2: And then he started losing it from the top of
• 17:20
  Speaker 2: his head first, and so he had like a bald
• 17:23
  Speaker 2: patch on the top of his head.
• 17:25
  Speaker 3: And he was the chunkiest baby ever.
• 17:27
  Speaker 2: He had like more rolls on his thighs than I've
• 17:30
  Speaker 2: ever seen a baby have, which was absolutely adorable. But anyway,
• 17:34
  Speaker 2: he had a definite Danny DeVito.
• 17:37
  Speaker 3: Stage, which I thought.
• 17:40
  Speaker 2: Was so cute. But every time I looked at him,
• 17:42
  Speaker 2: I would chuckle and think about Danny DeVito.
• 17:45
  Speaker 1: And is Danny DeVito like the epitome of cute?
• 17:48
  Speaker 3: Though I like, no, but my son was.
• 17:51
  Speaker 2: And so sometimes as a mom, you hold very you know,
• 17:55
  Speaker 2: discordant ideas in your head.
• 17:56
  Speaker 3: And it's fine.
• 17:57
  Speaker 1: Because you know, I will admit that when I see babies,
• 18:00
  Speaker 1: some of them are very cute. Not every baby is cute,
• 18:03
  Speaker 1: and I feel like people think it's weird to say that,
• 18:05
  Speaker 1: but it's true, Like some babies look like Richard Nixon,
• 18:09
  Speaker 1: you know, or Churchill, and that that's not cute.
• 18:11
  Speaker 2: I one hundred percent agree some babies are not cute.
• 18:15
  Speaker 2: I'll go on the record with you there. This is
• 18:17
  Speaker 2: going to be the last episode. People listen to of
• 18:19
  Speaker 2: our podcast.
• 18:20
  Speaker 1: But I'm sure your little Danny DeVito was very.
• 18:22
  Speaker 3: It was so cute.
• 18:23
  Speaker 2: And anyway, he ended up being a you know, blonde haired,
• 18:26
  Speaker 2: blue eyed Quti and he would have been cute if
• 18:29
  Speaker 2: he had still had dark hair too. But anyway, how
• 18:32
  Speaker 2: does our hair end up one color or another? So
• 18:35
  Speaker 2: maybe that's a good place to start. Yeah, And the
• 18:38
  Speaker 2: answer is it's complicated. And I feel like when we
• 18:42
  Speaker 2: were in elementary school, we were told that, like this
• 18:45
  Speaker 2: was something that was pretty easy to figure out, like
• 18:47
  Speaker 2: if you have two brown headed parents, you're probably gonna
• 18:49
  Speaker 2: have a brown headed kid. And I guess I got
• 18:51
  Speaker 2: the sense when I was younger that this was like
• 18:53
  Speaker 2: a dominant, recessive, easy trait to figure out.
• 18:57
  Speaker 3: Researching it, that absolutely does.
• 18:59
  Speaker 2: Not seem to be the There's like a hundred genes
• 19:02
  Speaker 2: or something that contribute to the color of your hair.
• 19:04
  Speaker 2: One of the more important ones is a receptor whose
• 19:07
  Speaker 2: name I won't say so that I don't have to
• 19:09
  Speaker 2: hear from Daniel, but it's a receptor.
• 19:12
  Speaker 1: Look at that I've trained you. I don't even need
• 19:14
  Speaker 1: to be hair anymore. You've learned.
• 19:17
  Speaker 3: Anyway.
• 19:18
  Speaker 1: But I have to say I've done this experiment myself, oh,
• 19:21
  Speaker 1: because I have dark hair and dark eyes, and my wife,
• 19:25
  Speaker 1: with her Danish Irish heritage, has blonde hair and light
• 19:29
  Speaker 1: colored eyes and light skin. And both of my kids
• 19:32
  Speaker 1: have light colored hair and light colored eyes. And you
• 19:36
  Speaker 1: know the simple understanding of biologies, like my traits are
• 19:40
  Speaker 1: dominant and hers are assessive, and yet hers one out well,
• 19:42
  Speaker 1: so it must be more complicated, or she cloned herself in
• 19:45
  Speaker 1: the lab.
• 19:46
  Speaker 2: I mean, I wouldn't put it past her. She's a
• 19:48
  Speaker 2: very smart biologist. But yes, these things are complicated. And
• 19:52
  Speaker 2: so the thing that gives your hair color is a
• 19:56
  Speaker 2: pigment that we have two versions of. We have a
• 19:59
  Speaker 2: version that give gives you like black and brown colors
• 20:02
  Speaker 2: and a version that gives you sort of blonde, reddish
• 20:04
  Speaker 2: sorts of colors. And we have receptors in our like
• 20:09
  Speaker 2: hair follicles and the cells that are important for making
• 20:11
  Speaker 2: hair color, and those receptors essentially they'll get bound by
• 20:15
  Speaker 2: a hormone, and if they get bound by a hormone,
• 20:17
  Speaker 2: they're like, bam, I'm making more you know, black for example, Okay,
• 20:21
  Speaker 2: And so it's all about like what receptors you have
• 20:24
  Speaker 2: and the hormone messages that are being sent to those receptors.
• 20:28
  Speaker 1: So I think this is fascinating because it's more complex
• 20:30
  Speaker 1: than people usually imagine, where like you have things encoded
• 20:34
  Speaker 1: in your genes that your body does. Instead, you have
• 20:36
  Speaker 1: things encoded in your genes that your body can do,
• 20:39
  Speaker 1: and whether it does them depends on whether it gets
• 20:42
  Speaker 1: messages like okay, now do this. Yes, Like you have
• 20:45
  Speaker 1: this library of capacities and only some things actually get
• 20:48
  Speaker 1: turned on. And that's fascinating.
• 20:49
  Speaker 2: Yeah, right, And so my understanding is that part of
• 20:52
  Speaker 2: the story about why hair color can change when kiddos
• 20:55
  Speaker 2: are very young is that when you are in your mom,
• 20:59
  Speaker 2: you're getting bathed in her hormones. So the receptors in
• 21:03
  Speaker 2: your body are getting messages that your body's not producing,
• 21:06
  Speaker 2: but your mom's body is, and so that can influence
• 21:09
  Speaker 2: your hair color.
• 21:10
  Speaker 1: And I wish you all had just seen Kelly's little
• 21:12
  Speaker 1: dance she did when she said you're in.
• 21:14
  Speaker 3: Your mom, I may it's probably a great place.
• 21:17
  Speaker 1: To be, you like, getting all cozy there, You're like mmmmm.
• 21:22
  Speaker 2: I mean I personally was a baby who stayed in
• 21:25
  Speaker 2: the womb for an extra couple weeks until they eventually
• 21:28
  Speaker 2: had to kick me out.
• 21:29
  Speaker 3: And so, you know, I imagine it's a lovely place
• 21:31
  Speaker 3: in there, much easier than real life.
• 21:36
  Speaker 2: But anyway, so partly, when you're very young, you're getting
• 21:42
  Speaker 2: exposed to the hormones that your mom makes. But then
• 21:44
  Speaker 2: as you get older, you start making your own hormones,
• 21:47
  Speaker 2: and you start making more of your own hormones or
• 21:49
  Speaker 2: different kinds of hormones, and so the messages that your
• 21:53
  Speaker 2: hair receptors are getting change over time, Okay, and that
• 21:57
  Speaker 2: explains why your hair can go from being one color
• 22:00
  Speaker 2: when you're young to another color when you're older. And
• 22:03
  Speaker 2: it's apparently very common for light haired kids to end
• 22:07
  Speaker 2: up having darker hair, and part of that has to
• 22:11
  Speaker 2: do with like hormones. During puberty, you start, you know,
• 22:15
  Speaker 2: making more hormones. Those hormones are also talking to your
• 22:17
  Speaker 2: hair receptors. But your hair doesn't change color overnight because
• 22:22
  Speaker 2: of something that we talked about in Listener Questions, episode
• 22:25
  Speaker 2: number twenty five, and this is the episode that was
• 22:27
  Speaker 2: being referred to by the listeners where they were talking
• 22:31
  Speaker 2: about why you sometimes go gray after a very stressful event. Oh,
• 22:35
  Speaker 2: I see, And so this is the hair cycle and
• 22:38
  Speaker 2: the idea here is that each follicle on your head
• 22:42
  Speaker 2: has a cycle. Wherefore, something like four to six years,
• 22:46
  Speaker 2: your hair is growing continuously.
• 22:48
  Speaker 1: And you just say, wherefore, as in you know, like
• 22:51
  Speaker 1: colonial times transition sentences, did I don't know.
• 22:54
  Speaker 2: I'm trying to think about what I'm going to say next,
• 22:56
  Speaker 2: and so I've already forgotten what I said two for herewith.
• 23:02
  Speaker 3: Much ado about hair today anyway.
• 23:06
  Speaker 1: So it takes some time for these things to register.
• 23:08
  Speaker 2: Well, yeah, so your hair will grow for four to
• 23:10
  Speaker 2: six years, but then your hair will take a break
• 23:12
  Speaker 2: and it will rest. And during that resting stage, the
• 23:16
  Speaker 2: cells that produce pigments that go into your hair de
• 23:21
  Speaker 2: and then you have stem cells that will produce more
• 23:24
  Speaker 2: of the pigment making cells, and those new, fresh baby
• 23:28
  Speaker 2: like pigment making cells will go down into your hair
• 23:31
  Speaker 2: follicle to start the cycle again.
• 23:32
  Speaker 1: Got it?
• 23:33
  Speaker 2: And so you need one set of cells to dye
• 23:37
  Speaker 2: and a new set of cells to come in with
• 23:39
  Speaker 2: their new instructions reflecting the new hormone mill you and
• 23:43
  Speaker 2: your teenage body before you start getting that change in
• 23:47
  Speaker 2: hair color.
• 23:48
  Speaker 1: I see. So it's not just that we shouldn't think
• 23:51
  Speaker 1: of our cells as having one hair color, but instead
• 23:54
  Speaker 1: we should think of ourselves as capable of producing a spectrum,
• 23:58
  Speaker 1: and the color that's actually on your head somehow reflects
• 24:01
  Speaker 1: the history of the hormones that your hair cells have received,
• 24:06
  Speaker 1: but also in a time delayed way because cells have
• 24:10
  Speaker 1: to die and be replaced. So in some sense, like
• 24:13
  Speaker 1: a person who has brown hair is telling me that,
• 24:17
  Speaker 1: like over the last few years, their hair cells have
• 24:20
  Speaker 1: received the hormones to produce brown yes ish.
• 24:25
  Speaker 2: But just to clarify, like you said that we've got
• 24:27
  Speaker 2: a gradient of hair colors, I don't think I have
• 24:30
  Speaker 2: anything in me that could make me make red hair,
• 24:34
  Speaker 2: Like I don't really nothing.
• 24:36
  Speaker 1: There's nothing that could happen I will not impact.
• 24:40
  Speaker 2: I don't think that I have the genes for like
• 24:42
  Speaker 2: the right kind of receptors or something like that. So
• 24:45
  Speaker 2: I'm not capable of producing red hair, but I am
• 24:49
  Speaker 2: capable of producing you know, like a range of brownie
• 24:52
  Speaker 2: black colors or something like that.
• 24:55
  Speaker 1: So our genomes can control the sort of spectrum that
• 24:58
  Speaker 1: hormones can influence them.
• 25:00
  Speaker 2: Yes, sense, okay, or at least that is how I
• 25:03
  Speaker 2: understood it what I was doing the reading.
• 25:04
  Speaker 3: So hopefully that's totally correct.
• 25:06
  Speaker 2: If not, write to me and tell me I'm wrong.
• 25:08
  Speaker 2: I always want to know.
• 25:09
  Speaker 1: And is it like an on off thing, you know,
• 25:11
  Speaker 1: if I get no hormones to my producing blonde and
• 25:13
  Speaker 1: then you have to get hormones to produce brown, or
• 25:16
  Speaker 1: is that I need to get the blonde hormones or
• 25:19
  Speaker 1: get the brown hormones.
• 25:20
  Speaker 3: I think it's a little more complicated.
• 25:22
  Speaker 2: So it can depend on like how many copies of
• 25:26
  Speaker 2: the genes you have for certain receptors. And so if
• 25:29
  Speaker 2: you have like both copies of the genes for a
• 25:32
  Speaker 2: certain receptor, you're like more likely to produce brown, and
• 25:35
  Speaker 2: you're more receptive to the amounts.
• 25:37
  Speaker 3: Of hormones that are in your body.
• 25:39
  Speaker 2: But we have now slammed into the wall of Kelly's
• 25:42
  Speaker 2: knowledge head one hundred miles an hour.
• 25:46
  Speaker 1: So summary is it's complicated.
• 25:48
  Speaker 2: Right, It is complicated, over one hundred genes involved, it
• 25:51
  Speaker 2: sounds like, and it changes over the course of your
• 25:54
  Speaker 2: life as your hormones change over the course of your life.
• 25:57
  Speaker 2: So the listeners also wanted to know if it was
• 26:00
  Speaker 2: evolutionarily advantageous that their babies were going from blonde headed
• 26:05
  Speaker 2: babies to darker haired babies. Right and at the end
• 26:09
  Speaker 2: of the day, I think the answer is probably not.
• 26:12
  Speaker 3: We don't like. We probably don't know.
• 26:14
  Speaker 2: I can't see a benefit of like, you know, does
• 26:16
  Speaker 2: a blonde haired baby hide better in the snow? And
• 26:20
  Speaker 2: like if you you know, worried about predators around. I
• 26:22
  Speaker 2: can't come up with a good explanation.
• 26:24
  Speaker 1: And it's not about like, blonde haired babies are cuter,
• 26:27
  Speaker 1: because we know that moms will find their own babies cute,
• 26:29
  Speaker 1: even if they do look like Richard Nixon or Danny DeVito.
• 26:34
  Speaker 3: He was the cutest anyway.
• 26:38
  Speaker 2: But so I looked for hypotheses that people came up with. Yeah,
• 26:42
  Speaker 2: and the closest I could come up with is that
• 26:44
  Speaker 2: blonde and red hair might just be a side effect
• 26:48
  Speaker 2: of needing to have a lighter colored skin when you
• 26:51
  Speaker 2: live in areas that get less sunlight. So UV light
• 26:56
  Speaker 2: is important for us for the production of vitamin D,
• 26:59
  Speaker 2: and so if you live in areas that get less
• 27:01
  Speaker 2: sunlight or darker for more times of the year, having
• 27:05
  Speaker 2: lighter skin allows you to absorb more of that UV
• 27:08
  Speaker 2: light and helps you with problems related to vitamin D.
• 27:11
  Speaker 2: And so as our skin lightened, we might have ended
• 27:15
  Speaker 2: up with lighter hair as sort of a side effect
• 27:18
  Speaker 2: of the lighter skin, because a lot of the same
• 27:20
  Speaker 2: pigments that go in your hair are also found in
• 27:23
  Speaker 2: your skin. So this doesn't tell us why it's beneficial
• 27:27
  Speaker 2: for your hair color to change from when you're a
• 27:29
  Speaker 2: baby to when you're an adult. But I think the
• 27:33
  Speaker 2: point is that hair color in general, like having a
• 27:37
  Speaker 2: variety of hair colors, isn't really something that selection has
• 27:40
  Speaker 2: probably acted on. It's probably just something that got pulled
• 27:43
  Speaker 2: along because of something that was happening to our skin.
• 27:47
  Speaker 2: And so you wouldn't necessarily expect there to be an
• 27:49
  Speaker 2: evolutionary advantage to your hair going from blonde to darker
• 27:54
  Speaker 2: colored when hair color is just sort of like pulled
• 27:57
  Speaker 2: along because of selection on something else anyway.
• 28:00
  Speaker 1: Right, And so this is sort of a subtle point
• 28:02
  Speaker 1: in evolution, at least for a physicist, that it's not
• 28:05
  Speaker 1: necessary for every trait you have, even ones that have
• 28:08
  Speaker 1: survived selection, to be individually advantageous. They can just be
• 28:13
  Speaker 1: linked to something else, which is an advantage. So, for example,
• 28:16
  Speaker 1: of being a physicist is an advantage, but it also
• 28:20
  Speaker 1: means you have a terrible sense of humor. Then you
• 28:22
  Speaker 1: might ask, like, how do all these people with terrible
• 28:25
  Speaker 1: sensitive humor find mates and have children and whatever. And
• 28:28
  Speaker 1: the answer is because of their amazing physics knowledge. And
• 28:31
  Speaker 1: that's the reason it survived, just as an example to
• 28:34
  Speaker 1: illustrate the point.
• 28:35
  Speaker 2: That seems like two hurdles to get over but instead
• 28:37
  Speaker 2: of just one. But I think I understand what you
• 28:39
  Speaker 2: were trying to get at there. But I want to
• 28:41
  Speaker 2: be really clear that, like the stuff that I just
• 28:44
  Speaker 2: said was pretty hand wavy, I was trying to find
• 28:47
  Speaker 2: some answer other than I don't know, but I wanted
• 28:50
  Speaker 2: to give at least a guess. Anyway, I don't think
• 28:53
  Speaker 2: we really know the answer, but that might be what's
• 28:56
  Speaker 2: going on, all right, cool, Okay, So I think that
• 28:59
  Speaker 2: that answers our listeners questions, and so let's go ahead
• 29:03
  Speaker 2: and see what they had to say.
• 29:05
  Speaker 7: Hello again, Daniel and Kelly, thanks for returning to the
• 29:08
  Speaker 7: subject taking some time to answer further questions about hair color.
• 29:13
  Speaker 7: I think I understand a little more now. I understand
• 29:17
  Speaker 7: how both genes and hormones play into the variability of
• 29:21
  Speaker 7: hair color across people and across time. And more than that,
• 29:25
  Speaker 7: I think I understand something about how these questions and
• 29:28
  Speaker 7: answers work because I knew that Kelly was going to
• 29:32
  Speaker 7: say it's complicated about three seconds before Kelly said it's complicated.
• 29:39
  Speaker 4: Thanks again, Kelly, your answer on hair color was very
• 29:43
  Speaker 4: informative and I actually learned something.
• 29:46
  Speaker 2: Thank you, and we're back and now we've got a
• 30:08
  Speaker 2: question from down in Palm Springs, California.
• 30:13
  Speaker 8: This is Don Vileeen in Palm Springs, California. Daniel and Kelly,
• 30:17
  Speaker 8: thank you for your podcast. There's always something new for
• 30:20
  Speaker 8: me to learn. Suppose there's no iron in the surface
• 30:23
  Speaker 8: layer of a planet, how would an intelligent being who
• 30:27
  Speaker 8: has evolved on that planet discover magnetism? Are other elements
• 30:31
  Speaker 8: sufficiently magnetic or likely sufficiently plentiful to take the place
• 30:36
  Speaker 8: of iron? And discovering magnetism is understanding magnetism and likely
• 30:40
  Speaker 8: electricity as well, a necessary condition for a civilization to
• 30:44
  Speaker 8: advance to a scientific level where they could receive and
• 30:48
  Speaker 8: send signals through space other than whatever visible light they
• 30:53
  Speaker 8: could see. And of course, so far all planets with
• 30:57
  Speaker 8: any intelligent life have had iron on or near their surface.
• 31:02
  Speaker 8: I wonder how delayed their scientific progress would have been
• 31:06
  Speaker 8: without iron.
• 31:07
  Speaker 1: All right, Don, thank you for thinking so deeply about
• 31:10
  Speaker 1: the experience of intelligent aliens living on a planet without
• 31:14
  Speaker 1: iron really fascinating thought experiment.
• 31:17
  Speaker 3: Daniel already wants to be your BFF.
• 31:23
  Speaker 1: Well, I think before we answer Don's question about an
• 31:26
  Speaker 1: alternative planet, we have to remind everybody how we discovered
• 31:29
  Speaker 1: magnets and how it fed into our ability to send
• 31:32
  Speaker 1: radio signals to potential aliens.
• 31:35
  Speaker 3: Give it to me, Daniel.
• 31:36
  Speaker 1: Magnets have been known almost forever, I mean basically before
• 31:39
  Speaker 1: we have any recorded histories. So historians refer to this
• 31:42
  Speaker 1: as in antiquity, which basically means we've known about this
• 31:45
  Speaker 1: forever and we can't tell when it was discovered. And
• 31:49
  Speaker 1: that's because we have a lot of iron on our
• 31:51
  Speaker 1: planet and there's a lot of magnets just sort of
• 31:53
  Speaker 1: lying around, and historically they call these things loadstones. So
• 31:58
  Speaker 1: you have iron and it gets oxidized with oxygen, again,
• 32:02
  Speaker 1: our friend, because oxygen likes to bind with everything, and
• 32:05
  Speaker 1: it makes something called magnetite and it'll just like sit
• 32:08
  Speaker 1: on the surface and be magnetic. And so we have
• 32:11
  Speaker 1: writings from like ancient Greece and China and India, people
• 32:14
  Speaker 1: writing about these rocks they found that will attract iron.
• 32:19
  Speaker 1: And so this has been known.
• 32:20
  Speaker 2: Forever, and did they use that iron for anything like
• 32:23
  Speaker 2: to forge swords and stuff.
• 32:26
  Speaker 1: Yes, So once we got to the iron age and
• 32:28
  Speaker 1: people were like smelting iron and making iron and stuff,
• 32:31
  Speaker 1: then people noticed this and then using magnets for practical
• 32:35
  Speaker 1: purposes like navigation. That's actually much more recent. It's like
• 32:39
  Speaker 1: maybe a thousand years ago in China and in Europe,
• 32:42
  Speaker 1: the people figured out this whole connection between magnets and
• 32:46
  Speaker 1: directions on the earth. So people have been using magnets
• 32:50
  Speaker 1: in technology for about a thousand years, but it was
• 32:53
  Speaker 1: only a couple of hundred years ago that people connected
• 32:56
  Speaker 1: electricity obviously also known in antiquity, you know, lightning and
• 33:01
  Speaker 1: static electricity to magnetism. And these were really important experiments
• 33:06
  Speaker 1: by Orsted. Essentially, he connected electricity and magnetism because he
• 33:10
  Speaker 1: accidentally ran a bunch of currents through wires near a
• 33:14
  Speaker 1: compass and saw the compass twitch and he was like,
• 33:16
  Speaker 1: wait a second, why is it when I have electricity
• 33:20
  Speaker 1: it affects the magnets. And that was the first observed
• 33:23
  Speaker 1: connection between electricity and magnetism, and that led to a
• 33:26
  Speaker 1: whole avalanche, you know, and Peer's law, the bio Savart law,
• 33:30
  Speaker 1: eventually unification by James Clerk Maxwell in the eighteen sixties
• 33:35
  Speaker 1: of electricity and magnetism into a single coherent theory of
• 33:39
  Speaker 1: a combined phenomenon. That's when we realized these two things
• 33:42
  Speaker 1: are just the front and back of a single elephant.
• 33:45
  Speaker 1: They're not completely separate phenomena. We've just noticed them differently
• 33:49
  Speaker 1: and never connected them. And Maxwell showed us how they're
• 33:52
  Speaker 1: intimately connected. They're really just one phenomena.
• 33:55
  Speaker 2: This tangent's not going to go too far, I promise,
• 33:57
  Speaker 2: But like eighteen fifty four is when John Snow figured
• 33:59
  Speaker 2: out the dolera pump stuff, right, Like, so check out
• 34:01
  Speaker 2: our cholera episodes. What an amazing time it must have
• 34:05
  Speaker 2: been to be alive. When we're figuring all of this
• 34:07
  Speaker 2: stuff out, We're like, oh, it's you know, you don't
• 34:09
  Speaker 2: get cholera because you're breathing stuff in it's in the water.
• 34:12
  Speaker 2: Of course, you live in a time where the water
• 34:14
  Speaker 2: could give you cholera. That's less good. But like, you know,
• 34:16
  Speaker 2: we're figuring out all of this stuff was about electricity
• 34:18
  Speaker 2: and magnetism, Like it must have been really exciting.
• 34:21
  Speaker 1: Yeah, and I hope that in one hundred and fifty years,
• 34:24
  Speaker 1: podcasters wax philosophical about how amazing it was to be
• 34:27
  Speaker 1: alive now when we're figuring all this stuff out, because
• 34:30
  Speaker 1: there's still a huge amount of stuff to figure out
• 34:32
  Speaker 1: about the universe and biology and even.
• 34:34
  Speaker 3: Chemistry, oh whoa, even chemistry.
• 34:38
  Speaker 1: And it is chemistry that tells us basically why iron
• 34:42
  Speaker 1: is so amazing. Iron is a great way to discover
• 34:45
  Speaker 1: magnetism because number one, there's a lot of it. The
• 34:48
  Speaker 1: Earth is like thirty two percent iron, So there's just
• 34:51
  Speaker 1: a whole bunch of iron on Earth. And that's not
• 34:54
  Speaker 1: unusual for rocky planets because stars make iron. Stars member
• 34:58
  Speaker 1: are doing fusion. There's squeezing protons together to make helium,
• 35:02
  Speaker 1: and that helium gets squeezed together, you get carbon and
• 35:05
  Speaker 1: oxygen and neon and heavier stuff. And if the star
• 35:09
  Speaker 1: is hot enough to squeeze together these heavier elements, you
• 35:12
  Speaker 1: can keep doing that all the way up to iron.
• 35:15
  Speaker 1: Above iron. It costs energy to fuse heavy elements together,
• 35:19
  Speaker 1: so stars don't make a whole lot of stuff above iron.
• 35:22
  Speaker 1: So iron is sort of the natural endpoint for stars
• 35:25
  Speaker 1: fusion process of manufacturing heavy elements. So there's a ton
• 35:29
  Speaker 1: of it in the universe, and that's why it dominates
• 35:32
  Speaker 1: our planet's core. And that's very helpful because it's really
• 35:36
  Speaker 1: really good at making magnets. Remember where magnetism comes from.
• 35:41
  Speaker 1: Electricity comes from electric charges you can have like an electron.
• 35:44
  Speaker 1: It makes an electric field. We don't have magnetic charges
• 35:48
  Speaker 1: in the same way. But there's this connection between electricity
• 35:51
  Speaker 1: and magnetism that a moving electric charge will make a
• 35:55
  Speaker 1: magnetic field. So you take your electron, you move it
• 35:58
  Speaker 1: in a circle, you get a magnetic field. That's how
• 36:01
  Speaker 1: an electromagnet works. Or if you have an electron and
• 36:04
  Speaker 1: it has a spin to it, that kind of quantum
• 36:07
  Speaker 1: mechanical motion will also give it a tiny little magnetic field.
• 36:10
  Speaker 1: So electrons are little magnets essentially, and iron has a
• 36:15
  Speaker 1: partially filled outer shells called the three D subshell, as
• 36:19
  Speaker 1: there's room in there for a bunch of electrons. And
• 36:22
  Speaker 1: remember electrons fill empty slots individually before pairing up, which
• 36:26
  Speaker 1: means that because there's four unpaired electrons, they're all spinning
• 36:30
  Speaker 1: in the same direction. There's not like one up and
• 36:33
  Speaker 1: one down. They all like to fill the up further
• 36:35
  Speaker 1: fields it down. So iron has a bunch of these
• 36:38
  Speaker 1: unpaired electrons all spinning in the same direction, making a
• 36:42
  Speaker 1: little magnetic field. And the atomic spacing of iron is
• 36:46
  Speaker 1: perfect to allow these electrons to like lock their spins
• 36:49
  Speaker 1: and neighboring atoms into parallel alignments. So you get all
• 36:53
  Speaker 1: these electrons from all these iron atoms, all pointing in
• 36:55
  Speaker 1: the same direction, and those tiny little magnets add up
• 36:59
  Speaker 1: to a big magnet sticks to your refrigerator.
• 37:01
  Speaker 3: So ICP was wrong. We know how magnets work. We
• 37:05
  Speaker 3: got this. There's no magic, no mystery there.
• 37:08
  Speaker 1: ICP is right about a lot of stuff.
• 37:10
  Speaker 3: But yeah, all right, let's let's move on magnets.
• 37:16
  Speaker 1: All right, So what if you didn't have iron? Right?
• 37:18
  Speaker 1: Iron is great, We used iron in our discovery of magnets.
• 37:21
  Speaker 1: Don is like, well, what if you didn't have it,
• 37:23
  Speaker 1: could you still discover magnetism. So iron is involved in
• 37:27
  Speaker 1: essentially all naturally occurring very powerful magnets. But it is
• 37:32
  Speaker 1: possible to have magnetic materials without any iron. So, for example,
• 37:37
  Speaker 1: pure nickel is a ferromagnet. Ferromagnets are just like iron.
• 37:42
  Speaker 1: They're easy to align up, and they can make permanent magnets.
• 37:45
  Speaker 1: Most of the magnets out there that are nickel. Magnets
• 37:48
  Speaker 1: are mostly iron, but if you have a very pure
• 37:51
  Speaker 1: deposit of nickel, that will be a ferromagnet. On Earth,
• 37:55
  Speaker 1: these things are very very rare because nickel mixes with stuff.
• 37:59
  Speaker 1: It's hard to find your nickel, but it is possible.
• 38:02
  Speaker 1: So if you have aliens on a planet with like
• 38:04
  Speaker 1: lots of pure nickel deposits, they can use those the
• 38:07
  Speaker 1: way we used loadstones.
• 38:09
  Speaker 2: Did we talk about what pharaoh means? What is a
• 38:11
  Speaker 2: ferromagnet as opposed to a magnet magnet?
• 38:14
  Speaker 1: Yeah? So a ferromagnet is a material where all these
• 38:16
  Speaker 1: electrons can be lined up in the same direction and
• 38:19
  Speaker 1: they can stay a magnet. So a ferromagnet, like if
• 38:22
  Speaker 1: you put it near another strong magnet and all of
• 38:24
  Speaker 1: its magnetic regions will get lined up and it'll stay
• 38:28
  Speaker 1: a magnet. Paramagnetic material is one that's only a magnet
• 38:32
  Speaker 1: when it's near another magnet, like they don't stay locked
• 38:35
  Speaker 1: in place, And so ferromagnets are what you want.
• 38:38
  Speaker 3: Oh good, Can we have more jargon, Daniel, Oh.
• 38:42
  Speaker 1: We can, yes, we could bring it all sorts of
• 38:44
  Speaker 1: biological jargon.
• 38:45
  Speaker 2: Okay, all right, all right, right? What else will make
• 38:48
  Speaker 2: a ferromagnet.
• 38:49
  Speaker 1: So you can use cobalt. Cobalt tight is naturally ferromagnetic
• 38:54
  Speaker 1: and has no iron in it. This cobalt and arsenic
• 38:58
  Speaker 1: and sulfur in that it's much less abundant than iron
• 39:01
  Speaker 1: on Earth, but it's possible. They're also like neodymium and
• 39:05
  Speaker 1: gadolinium and dysprosium. These have really strong magnetic behavior, but
• 39:10
  Speaker 1: mostly with iron. So people AIS are thinking like, what
• 39:13
  Speaker 1: about rare Earth materials? Those are magnetic mostly those are
• 39:17
  Speaker 1: powerful magnets with iron combined with iron. Without iron, they're
• 39:21
  Speaker 1: mostly paramagnets, so they're not useful in the same way.
• 39:25
  Speaker 1: So there are some alternative ways to discover magnets. But
• 39:28
  Speaker 1: if you don't have any iron, you probably don't have
• 39:30
  Speaker 1: any pure nickel or cobalt, or either something went wrong
• 39:33
  Speaker 1: or you're in a weird kind of solar system. And
• 39:37
  Speaker 1: so let's imagine you have no magnets on your planet.
• 39:40
  Speaker 1: You're an alien civilization. You just have no loadstones, no compasses.
• 39:44
  Speaker 1: Could you still discover electromagnetism and send messages through space?
• 39:49
  Speaker 1: That's what Don is asking, And the answer is yes,
• 39:52
  Speaker 1: because magnetism is connected to electricity, and so if you
• 39:56
  Speaker 1: figure out electricity, you can figure out magnetism without any
• 40:01
  Speaker 1: naturally occurring magnets. Remember how we discover the connection between
• 40:05
  Speaker 1: electricity and magnetism is through electrical currents. Orstead had these currents,
• 40:11
  Speaker 1: he had electricity, and he discovered, oh, that's magnetic and
• 40:15
  Speaker 1: it was helpful. He discovered it because there was a
• 40:17
  Speaker 1: magnet nearby. But you don't need any magnets for that.
• 40:20
  Speaker 1: You just have like a couple of wires. You run
• 40:22
  Speaker 1: currents with them. They will attract each other or they
• 40:25
  Speaker 1: will repel each other. They turn into magnets. And so
• 40:29
  Speaker 1: you could start just by discovering like static electricity like
• 40:33
  Speaker 1: we did through amber. You know, you rub amber on cloth,
• 40:36
  Speaker 1: they will accumulate a charge. You observe lightning, you do experiments,
• 40:40
  Speaker 1: you can definitely discover electricity without any magnetic materials on
• 40:44
  Speaker 1: the surface of your planet. You can develop like natural batteries,
• 40:48
  Speaker 1: all sorts of stuff, and then you start building currents
• 40:51
  Speaker 1: and you see this deflection. You will discover, just like
• 40:54
  Speaker 1: Orsted did, that electric currents produce these magnetic effects. You
• 40:58
  Speaker 1: wouldn't call it magnetism. You would think it's part of electricity,
• 41:02
  Speaker 1: and in that sense it might even be an advantage.
• 41:05
  Speaker 1: We have the disadvantage of thinking magnets and lightning are
• 41:08
  Speaker 1: totally different things. The front in the back of the
• 41:11
  Speaker 1: elephant are completely separate. But if you only start from
• 41:13
  Speaker 1: the back of the elephant and then you work your
• 41:15
  Speaker 1: way to the front, then you know already that they're connected.
• 41:18
  Speaker 1: So if you discover magnetism as a part of electricity,
• 41:22
  Speaker 1: that could be even an advantage.
• 41:24
  Speaker 3: What is the link here with communication?
• 41:28
  Speaker 1: The link is that radio waves, the way we like
• 41:31
  Speaker 1: to send messages into space and from person to person,
• 41:35
  Speaker 1: and the way your cell phone works, these are electromagnetic radiation.
• 41:39
  Speaker 1: So you're sending ripples in the electromagnetic field. An antenna
• 41:43
  Speaker 1: has a bunch of electrons in it that you're wiggling,
• 41:46
  Speaker 1: and so you're wiggling the electric field that it makes,
• 41:48
  Speaker 1: and that's what electromagnetic radiation is, are wiggles in the
• 41:51
  Speaker 1: electromagnetic field. So if you are going to send messages
• 41:55
  Speaker 1: through space, you have to understand electromagnetism at some level
• 41:59
  Speaker 1: in order to do that. And so that's why Don
• 42:01
  Speaker 1: is interested in this question of like, could you discover
• 42:03
  Speaker 1: electromagnetism without magnets? And I think the answer is yes,
• 42:07
  Speaker 1: you could discover purely through electricity. However, you don't have
• 42:12
  Speaker 1: to write like you could imagine communicating via electromagnetism without
• 42:16
  Speaker 1: really understanding what it is, because light is electromagnetism, and
• 42:21
  Speaker 1: you could be sending messages from planet to planet or
• 42:23
  Speaker 1: even star to star using essentially just optics. Like if
• 42:27
  Speaker 1: you develop very powerful sources of light, even if you
• 42:30
  Speaker 1: don't have a theory of electromagnetism, you could send those
• 42:34
  Speaker 1: pulses through space, you know, essentially visible light signaling.
• 42:38
  Speaker 3: Like Morse code or something like with a laser.
• 42:41
  Speaker 1: Yeah, essentially with a laser, yeah, Morse code. Or you know,
• 42:44
  Speaker 1: in the same way that you have signals encoded into
• 42:47
  Speaker 1: radio waves, you can encode a signal into laser pulses
• 42:51
  Speaker 1: through amplitude or through frequency modulation or whatever. So you know,
• 42:55
  Speaker 1: the bottom line is, I think you don't need iron
• 42:58
  Speaker 1: to discover magnetism, but it's an enormous advantage. It's possible
• 43:03
  Speaker 1: to discover it otherwise if you have some natural sources
• 43:06
  Speaker 1: of magnets. But the other route is just through pure electricity,
• 43:09
  Speaker 1: which will eventually lead you to understanding magnets anyway, and
• 43:13
  Speaker 1: then theory of electromagnetism, and then you'll be broadcasting I
• 43:16
  Speaker 1: love Lucy out into space. But you also don't have to,
• 43:20
  Speaker 1: and you could imagine other ways to send messages. Maybe
• 43:22
  Speaker 1: the be advanced particle physicists and they send us neutrino
• 43:25
  Speaker 1: bursts or something. And most likely the history of science
• 43:30
  Speaker 1: on that alien planet is even more alien than we
• 43:32
  Speaker 1: can ever imagine.
• 43:34
  Speaker 3: And Daniel's out there transmitting the message will trade humanity
• 43:37
  Speaker 3: for physics facts.
• 43:40
  Speaker 1: And Kelly is out there sending them all sorts of
• 43:42
  Speaker 1: biology jargon.
• 43:44
  Speaker 3: Oh, come on.
• 43:46
  Speaker 1: When we meet aliens, is that what you want to
• 43:48
  Speaker 1: talk to them about? You like, here's the name of
• 43:49
  Speaker 1: that receptor.
• 43:50
  Speaker 2: By the way, I want to say, what kind of
• 43:52
  Speaker 2: parasites do you have? Here's a bag for the stool sample.
• 43:57
  Speaker 1: I think I saw that show. It's called Alien Earth. No, okay,
• 44:03
  Speaker 1: all right, let's send this message over to Palm Springs
• 44:05
  Speaker 1: and see if we have answered Don's question about aliens.
• 44:10
  Speaker 9: Daniel and Kelly, thanks for the thorough and thoughtful discussion.
• 44:13
  Speaker 9: It's interesting to learn about magnetic elements and minerals that
• 44:17
  Speaker 9: are not iron I've always wanted a magnet that attracted
• 44:21
  Speaker 9: other metals. Like gold or copper. Some being somewhere as
• 44:25
  Speaker 9: likely already created a magnetic prism that refracts a magnetic
• 44:29
  Speaker 9: field to attract or repel whatever elements they specify. I
• 44:34
  Speaker 9: suppose that's similar to what the large Hadron collider it
• 44:36
  Speaker 9: certain does for fundamental particles. Just shrink cern to fit
• 44:41
  Speaker 9: in your hand, install the app, choose your element, and
• 44:44
  Speaker 9: go asteroid mining. I do have a biology question for Kelly.
• 44:49
  Speaker 9: If iron were very rare at Earth's surface, what color
• 44:53
  Speaker 9: would our blood be? Thank you again, I really enjoy
• 44:57
  Speaker 9: your podcast.
• 44:58
  Speaker 2: Wow, that's a great follow up question, don Okay, So
• 45:02
  Speaker 2: our bodies use a protein called hemoglobin, and iron is
• 45:06
  Speaker 2: used in hemoglobin and that binds oxygen and brings us
• 45:11
  Speaker 2: different places in the body. Okay, so you're asking, if
• 45:13
  Speaker 2: we don't have iron.
• 45:15
  Speaker 3: What would we do instead.
• 45:17
  Speaker 2: I have no idea what evolution would come up with,
• 45:20
  Speaker 2: but I need to have an answer. So the answer
• 45:23
  Speaker 2: I'm gonna give you is that mullusks, so like clams
• 45:27
  Speaker 2: and stuff, they have hemocyanin, which is a copper binding protein.
• 45:34
  Speaker 3: So instead of iron, it uses copper.
• 45:38
  Speaker 2: So if we lived on a planet with no iron,
• 45:40
  Speaker 2: maybe we would use this to bind oxygen instead, and
• 45:45
  Speaker 2: so if you were using this, the protein turns blue
• 45:50
  Speaker 2: when oxygen is bound to it, So I guess our
• 45:54
  Speaker 2: blood would be blue.
• 45:55
  Speaker 3: Which would be kind of epic.
• 45:57
  Speaker 2: Thanks for the question, don Thank you for sharing your
• 46:01
  Speaker 2: curiosity with us. We love getting questions from y'all, and
• 46:04
  Speaker 2: you can send us those questions through email at questions
• 46:07
  Speaker 2: at Daniel and Kelly dot org. Or you can connect
• 46:09
  Speaker 2: with us at our discord channel and you can get
• 46:11
  Speaker 2: an invite to our discord channel by going to Daniel
• 46:14
  Speaker 2: and Kelly dot org.
• 46:15
  Speaker 3: We hope to hear from you.
• 46:16
  Speaker 2: We answer every question, Daniel usually within thirty seconds, me
• 46:20
  Speaker 2: usually within about a week, but we answer them all
• 46:24
  Speaker 2: in a subset of them end up on the show.
• 46:26
  Speaker 1: That's right, and thank you for lending us your curiosity.
• 46:36
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• 46:38
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• 46:41
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• 46:44
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• 46:48
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• 46:48
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• 46:57
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• 46:58
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• 47:02
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• 47:03
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• 47:19
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