Latest / Daniel and Kelly’s Extraordinary Universe / Listener Questions about light and black holes

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Listener Questions about light and black holes · Daniel and Kelly’s Extraordinary Universe

• 0:08
  Speaker 1: Hey, Daniel, I have a light question for you. I
• 0:11
  Speaker 1: hope I am bright enough to answer it. See I
• 0:13
  Speaker 1: can tell you're taking this a little too lightly. Well,
• 0:15
  Speaker 1: you know, I'm happy to answer it and try to
• 0:18
  Speaker 1: lighten your intellectual load. Now I need a pretty awesome
• 0:21
  Speaker 1: answer here, something totally lit as the kids would say,
• 0:25
  Speaker 1: all right, what is it? I can illuminate for you?
• 0:28
  Speaker 1: All right, are you ready? What is a photon? Anyways,
• 0:33
  Speaker 1: that is not a lighthearted question, but go ahead, light
• 0:36
  Speaker 1: it up. Unfortunately, I don't have a very enlightening answer
• 0:39
  Speaker 1: for you. Just light puns. My puns are massless. Ye
• 0:58
  Speaker 1: Hi am or handmade cartoonists and the creator of PhD comics.
• 1:01
  Speaker 1: I'm Daniel. I'm a physicist and a professor at u
• 1:04
  Speaker 1: C Irvine, and now I find myself very light on
• 1:07
  Speaker 1: the puns. You're a shining example of in academia. No,
• 1:12
  Speaker 1: I just used up all my light puns, and now
• 1:14
  Speaker 1: my brain is like a black hole of ideas for
• 1:17
  Speaker 1: how to make more puns about light. You're dimming on
• 1:20
  Speaker 1: the punts there. Welcome to our podcast, Daniel and Jorge
• 1:24
  Speaker 1: Explain the Universe, a production of My Heart Radio in
• 1:27
  Speaker 1: which we try to shine a bright light on the
• 1:30
  Speaker 1: deepest mysteries of the universe. We wonder how everything works.
• 1:34
  Speaker 1: We wonder why it works at all. We wonder why
• 1:36
  Speaker 1: there is anything, how much of it there is, and
• 1:39
  Speaker 1: what rules it follows. We are amazed that we can
• 1:43
  Speaker 1: make sense of any of this incredible, crazy cosmos that
• 1:46
  Speaker 1: we find ourselves in, but we are appreciative that we can,
• 1:49
  Speaker 1: and we seek to share that little sliver of understanding
• 1:52
  Speaker 1: with you. That's right, It is a pretty amazing universe
• 1:54
  Speaker 1: full of light and shiny things for us to wonder
• 1:57
  Speaker 1: and ask questions about, like, for example, light or the
• 2:02
  Speaker 1: opposite of light, like black holes, big stars, giant stars,
• 2:06
  Speaker 1: small stars, dark matter, all kinds of things for us
• 2:09
  Speaker 1: to wonder about, because it's not just a universe filled
• 2:12
  Speaker 1: with stuff. It's a universe filled with stuff that is
• 2:15
  Speaker 1: sending us messages. We couldn't see stars in other solar
• 2:19
  Speaker 1: systems if they were not shooting light at us or
• 2:22
  Speaker 1: sending other kinds of particles. So don't imagine a universe
• 2:26
  Speaker 1: out there doing its mysterious stuff in the darkness. Instead,
• 2:29
  Speaker 1: all the crazy dancing that's happening in the physics inside
• 2:33
  Speaker 1: stars and inside black holes and all over the galaxy
• 2:36
  Speaker 1: is beaming you answers, beaming you clues at least to
• 2:39
  Speaker 1: lead you towards answers and understanding of the fundamental physics
• 2:43
  Speaker 1: that would explain it all. Yeah, the universe is bathing us,
• 2:46
  Speaker 1: but information about itself and have the laws that it
• 2:49
  Speaker 1: follows to make everything work, from giant stars and galaxies
• 2:52
  Speaker 1: to the tiny smallest molecules and particles. Assuming of course,
• 2:56
  Speaker 1: that the universe does follow laws. He's saying the universe
• 2:59
  Speaker 1: is some kind of out law, some kind of criminal universe.
• 3:02
  Speaker 1: Is it gon need to go to university jail. I
• 3:06
  Speaker 1: don't want to put a black mark on the reputation
• 3:08
  Speaker 1: of the universe in any sense I think you just did.
• 3:11
  Speaker 1: I'm just asking questions. You know, I wonder if Daniel
• 3:17
  Speaker 1: Whiteson broke the law again today. Is that the kind
• 3:20
  Speaker 1: of question that wouldn't that is harmless? Yeah? Yeah, exactly.
• 3:24
  Speaker 1: And I'm impressed with how well the universe so far
• 3:27
  Speaker 1: has been following laws, or put another way, how we've
• 3:30
  Speaker 1: been able to discover the laws the universe seems to
• 3:33
  Speaker 1: be following. But you know, there is a deep and
• 3:35
  Speaker 1: fundamental mystery there which is like, why is the universe
• 3:39
  Speaker 1: following laws at all, and is it possible to ever
• 3:42
  Speaker 1: come up with a single law that describes everything in
• 3:46
  Speaker 1: the universe. That's a little bit of an article of
• 3:48
  Speaker 1: faith in the whole process of science. Yeah, it's a
• 3:50
  Speaker 1: big question. Fortunately, the universe, as you said, is bright,
• 3:53
  Speaker 1: and it is full of things that shine and give
• 3:56
  Speaker 1: up light, and and that like gets to us, and
• 3:58
  Speaker 1: we can use that information to figure out if the
• 4:02
  Speaker 1: universe should be arrested or not. And that raises another
• 4:06
  Speaker 1: deep question, which is if the universe breaks the law,
• 4:09
  Speaker 1: who punishes it? Does it go to universe jail? In
• 4:11
  Speaker 1: what universe is that jail? Obviously there's a multiverse department
• 4:15
  Speaker 1: of justice. I'm amazed that I've never read that science
• 4:20
  Speaker 1: fiction novel. I think I think Marvel has it pretty
• 4:23
  Speaker 1: well covered. But a whole universe in jail, Wow, that's
• 4:28
  Speaker 1: quite the budget. Now they kill universes, oh man, they
• 4:31
  Speaker 1: shut them down. The death penalty for a universe. Usually
• 4:34
  Speaker 1: that gives me the shirts. Yeah, it's pretty pretty. It's
• 4:37
  Speaker 1: called the time authority. Oh that's right. Yeah, they do
• 4:40
  Speaker 1: cancel whole branches of the timeline. That's true. Well, let's
• 4:44
  Speaker 1: hope that never happens to us. We are just here
• 4:46
  Speaker 1: trying to figure out how the universe works. We're trusting
• 4:49
  Speaker 1: that it is following some laws and it's not putting
• 4:52
  Speaker 1: us in existential danger because we would like to understand
• 4:55
  Speaker 1: how it works. We look at all these photons that
• 4:58
  Speaker 1: come to our eyeballs and we try to make a
• 5:00
  Speaker 1: mental picture of how everything works. And sometimes we're confused.
• 5:03
  Speaker 1: Sometimes we see something we don't quite understand, and that,
• 5:06
  Speaker 1: of course leads to my favorite part of science, asking questions. Yeah,
• 5:10
  Speaker 1: and it's not just scientists who ask questions or love
• 5:12
  Speaker 1: to ask questions or have questions about the universe. It's everybody.
• 5:16
  Speaker 1: We all, at some point in our lives look up
• 5:18
  Speaker 1: at this guy and think, where did it all come from?
• 5:21
  Speaker 1: How does it all work? Why are we here? Who
• 5:23
  Speaker 1: is it that stole my chocolate? And how can I
• 5:25
  Speaker 1: put them in universe jail? These are big questions basically
• 5:28
  Speaker 1: everybody asks in their lifetime, because science is not just
• 5:31
  Speaker 1: a process that professors can do in their offices or
• 5:34
  Speaker 1: in their basement labs. It's just part of being human.
• 5:38
  Speaker 1: It's just like a way to codify and systematize the
• 5:41
  Speaker 1: natural feelings that we have of curiosity and investigation. It's
• 5:46
  Speaker 1: something that everybody can do, and it's something that everybody
• 5:48
  Speaker 1: is always doing as they maneuver in this world. Yeah,
• 5:52
  Speaker 1: all you have to do is observe the universe, think
• 5:54
  Speaker 1: about it, and use logic to work things out. That's
• 5:57
  Speaker 1: that's basically science right now. That's basically science. Also, drink coffee.
• 6:01
  Speaker 1: Coffee is a big part of it. I think you
• 6:05
  Speaker 1: don't drink any coffee anymore though, Does that mean that
• 6:07
  Speaker 1: you don't do any science? Well, I don't get paid
• 6:09
  Speaker 1: for it. If that's what you means. It's the coffee
• 6:12
  Speaker 1: drinking that I'm getting paid for over here, that's true.
• 6:14
  Speaker 1: It's the extra mile. Yeah, when you're ingest chemicals for something,
• 6:18
  Speaker 1: that means you're a pro. That's what goes to my
• 6:21
  Speaker 1: time sheets. Nine espressos today. Oh I'm getting over time,
• 6:25
  Speaker 1: over time, uh yeah, and overclocking your heart as well,
• 6:30
  Speaker 1: exactly and my brain. But what we love to do
• 6:33
  Speaker 1: is not just ask questions ourselves and talk about them,
• 6:36
  Speaker 1: but encourage you to ask questions. We hope that this
• 6:38
  Speaker 1: podcast tickles that inquisitive part of your brain and makes
• 6:42
  Speaker 1: you look around at your universe and think, do I
• 6:44
  Speaker 1: understand how this works? Can I figure this out? And
• 6:47
  Speaker 1: when you don't, we want you to write to us
• 6:49
  Speaker 1: with your questions so we can help you understand them.
• 6:52
  Speaker 1: So today on the podcast, we'll be tackling listener questions
• 7:01
  Speaker 1: light addition. Now it's just like a low calorie version
• 7:04
  Speaker 1: of our usual listener question episode. Welcome to Daniel and
• 7:08
  Speaker 1: Jorge on an intellectual diet. That's right, it's all cottage
• 7:11
  Speaker 1: cheese and can't to look today, folks, what is it? Aspertame?
• 7:15
  Speaker 1: We're going to give aspertain answers, the sweetest questions to
• 7:19
  Speaker 1: the sweetest mysteries in science, but with no calories. It's
• 7:23
  Speaker 1: gonna feel sweet when you listen to our answers, but
• 7:26
  Speaker 1: don't worry, you're not going to learn anything that is
• 7:29
  Speaker 1: promising here. Or maybe we should have very heavy answers
• 7:33
  Speaker 1: and people should like bench press us, you know, like
• 7:36
  Speaker 1: really massive, deep answers to the heaviest questions in the universe.
• 7:41
  Speaker 1: Maybe that should be a different podcast, the heavy edition,
• 7:44
  Speaker 1: the fitness version. The massive addition. We should be playing
• 7:47
  Speaker 1: like fitness music in the background, so I've already can
• 7:49
  Speaker 1: be like doing their crunches as they listen. That might
• 7:52
  Speaker 1: make it a little hard to talk. Yeah, I would
• 7:54
  Speaker 1: think of physicists would know that. But we do love
• 7:56
  Speaker 1: encouraging you to ask questions and to send us your question.
• 8:00
  Speaker 1: If you have questions about the way the universe works,
• 8:02
  Speaker 1: or there's something that's always puzzled you, please please please
• 8:05
  Speaker 1: write to us two questions at Daniel and Jorge dot com.
• 8:09
  Speaker 1: We answer all our emails. We answer all these questions,
• 8:12
  Speaker 1: and sometimes we might pick your question to answer here
• 8:15
  Speaker 1: on the podcast. Yeah, so today we have three awesome
• 8:18
  Speaker 1: questions and they're all in one way or another about
• 8:20
  Speaker 1: light kind of right or the lack thereof perhaps, Yeah, exactly, photons,
• 8:25
  Speaker 1: what they do when they hit stuff, how far they
• 8:27
  Speaker 1: can travel, and what's going on inside a black hole?
• 8:30
  Speaker 1: As always, I feel like everything comes back to the
• 8:33
  Speaker 1: black hole, one of the most massive mysteries in science.
• 8:36
  Speaker 1: Feel like it's kind of the rug for physicist. When
• 8:38
  Speaker 1: you hit a question that you don't know the answer to,
• 8:40
  Speaker 1: you're like, black hole on there. Why didn't I answer
• 8:45
  Speaker 1: your email? Oh it must have been routed into a
• 8:47
  Speaker 1: black hole. My apologies. So that works. Yeah, an email
• 8:51
  Speaker 1: black hole. That's how I would describe my regular imbob
• 8:54
  Speaker 1: exactly want to exceed a certain number of unread messages,
• 8:57
  Speaker 1: it just collapses. It creates a distorted and uh in
• 9:01
  Speaker 1: space and time? Yeah, all right, we'll start here with
• 9:03
  Speaker 1: our first question, which is about photons and what happens
• 9:06
  Speaker 1: when they hit stuff? And this question comes from Matthew
• 9:11
  Speaker 1: Daniel and horror. Hey, what's up? I loved the episode
• 9:15
  Speaker 1: about photons bumping into each other, but it really got
• 9:19
  Speaker 1: my brain spinning here, which is not difficult. What happens
• 9:25
  Speaker 1: to photons when they hit my skin? Are they just
• 9:29
  Speaker 1: absorbed and turned my skin a beautiful golden brown? What
• 9:35
  Speaker 1: happens when they hit solar panels? Why do things heat
• 9:38
  Speaker 1: up when they're hit by photons? What happens when photons
• 9:43
  Speaker 1: hit the opaque plastic cover on my little camper and
• 9:48
  Speaker 1: I can see light through it? Do some get through
• 9:50
  Speaker 1: and some don't? What happens when photons hit a mirror?
• 9:54
  Speaker 1: What happens when photons hit rock versus water, versus clouds?
• 10:00
  Speaker 1: I think you get the point. Boy, let's uh, let's
• 10:04
  Speaker 1: really dig in. It's going to be fotastic. All right, Wow,
• 10:12
  Speaker 1: I love that question. Yeah, that question or questions that
• 10:16
  Speaker 1: was like twenty different questions there. It was fotastic do
• 10:20
  Speaker 1: you think he was eating a bowl of fun as
• 10:22
  Speaker 1: he was thinking about these things. Hopefully it was diet foe. Yeah.
• 10:25
  Speaker 1: But uh, well, first of all, we should just say
• 10:27
  Speaker 1: what's up? Pat you back to you. Let me just
• 10:31
  Speaker 1: say how much I enjoyed hearing him spin out on
• 10:34
  Speaker 1: this question, realizing that there are really basic, deep questions
• 10:38
  Speaker 1: about how photons interact with matter and everything around us.
• 10:41
  Speaker 1: It is really complicated, So thank you very much for
• 10:43
  Speaker 1: inviting us to dig into it. Yeah. I think he
• 10:45
  Speaker 1: seemed to expand in his head as he was asking
• 10:48
  Speaker 1: the question on the idea that first of all, light
• 10:50
  Speaker 1: is everywhere. It's bouncing around everything and hitting everything. But
• 10:54
  Speaker 1: also there's kind of a huge variety of things that
• 10:57
  Speaker 1: like does. When it does seem to hit things right,
• 10:59
  Speaker 1: some lines, that goes through things, sometimes it bounces back,
• 11:02
  Speaker 1: sometimes it gets absorbed, sometimes it heats things up right,
• 11:05
  Speaker 1: there's kind of a wide range of things that light does. Yes,
• 11:08
  Speaker 1: light is very amazing and very complicated, and even though
• 11:11
  Speaker 1: it's everywhere in the world, it does react very differently
• 11:15
  Speaker 1: to different kinds of stuff. It's a great way to
• 11:17
  Speaker 1: show off like the fundamental quantum mechanics of our universe.
• 11:21
  Speaker 1: To understand all these different behaviors when light hits different
• 11:24
  Speaker 1: kinds of stuff. Yeah, so let's dig in, as Matthew requested,
• 11:28
  Speaker 1: So Daniel's started with the basics. What is light? What
• 11:31
  Speaker 1: is this thing we call light? Yeah? So the short
• 11:33
  Speaker 1: answer is, we really just don't know. Done. If we
• 11:36
  Speaker 1: don't know what light is and we don't know what
• 11:38
  Speaker 1: it does when it hits other things. Next question. We
• 11:41
  Speaker 1: don't know what light is in the sense that we
• 11:43
  Speaker 1: don't have like a good intuitive analog. I can't say
• 11:47
  Speaker 1: it's like a beach ball, or it's like a wave
• 11:49
  Speaker 1: in water. It's not like anything else we know. On
• 11:53
  Speaker 1: the other hand, we do have a very nice mathematical
• 11:57
  Speaker 1: description of what light does, so we can predict very
• 12:00
  Speaker 1: well what happens when light hits metal, or when light
• 12:03
  Speaker 1: hits plastic, or when light hits water, or when light
• 12:06
  Speaker 1: hits your skin. We can do all those calculations even
• 12:09
  Speaker 1: if we don't fundamentally know what light is in the
• 12:12
  Speaker 1: sense that we can't like translate it into something familiar. Wait,
• 12:15
  Speaker 1: what do you mean we don't know what it is?
• 12:16
  Speaker 1: I thought that light was, you know, excitations or wiggles
• 12:21
  Speaker 1: in the electromagnetic field that propagates across the universe, right,
• 12:25
  Speaker 1: isn't that the idea that the universe is filled with
• 12:27
  Speaker 1: quantum fields and the electromagnetic force is one of them,
• 12:31
  Speaker 1: and the wiggles in it are the photons. Yeah, that's
• 12:34
  Speaker 1: part of the mathematical description of how light works. We
• 12:38
  Speaker 1: can model light as a wiggle in the electromagnetic field,
• 12:42
  Speaker 1: and what happens to light when it hits something can
• 12:44
  Speaker 1: be predicted by solutions to these wave equations, which we
• 12:48
  Speaker 1: know mostly how to deal with in lots of circumstances,
• 12:51
  Speaker 1: like when they hit a barrier, or when they go
• 12:54
  Speaker 1: from air to water, or when it goes from air
• 12:56
  Speaker 1: to skin. We know mostly how to solve these problems.
• 12:59
  Speaker 1: We don't know what light is in the sense that
• 13:01
  Speaker 1: we don't really understand the fundamental quantum mechanics of it.
• 13:04
  Speaker 1: Like light is a wave in the sense that it's
• 13:06
  Speaker 1: fluctuations in this electromagnetic field. On the other hand, it
• 13:09
  Speaker 1: also acts like a particle because you can't observe all
• 13:12
  Speaker 1: of these waves directly. What you see are individual packets
• 13:15
  Speaker 1: of light that like go here or go there. So
• 13:17
  Speaker 1: there's something fundamentally probabilistic and quantum mechanical about light, and
• 13:21
  Speaker 1: in that sense, we don't really know like what light is,
• 13:25
  Speaker 1: that we do have the mathematics to describe it. Well,
• 13:27
  Speaker 1: you could also say that about everything else in the universe, right,
• 13:30
  Speaker 1: all the matter particles, all of the force particles, they're
• 13:33
  Speaker 1: all just quantum mechanical wave packets. Right. Yeah, absolutely, we
• 13:38
  Speaker 1: don't know, for example, what a particle is. My whole
• 13:41
  Speaker 1: episode talking about the various philosophical ideas for what it is.
• 13:45
  Speaker 1: That doesn't stop us from having a theory about it
• 13:48
  Speaker 1: and having mathematics that describe it, even if we don't
• 13:50
  Speaker 1: know who the subject of that mathematical story is. Right,
• 13:54
  Speaker 1: So if you ask me, like what is light? Then
• 13:57
  Speaker 1: boo boy, that's a whole big philosophical question. If you
• 13:59
  Speaker 1: ask me, can you predict what happens when light hits
• 14:02
  Speaker 1: a mirror? Oh? Yeah, that I can certainly do. Well. Fortunately,
• 14:06
  Speaker 1: this is not a philosophy podcast, so we'll just focus
• 14:10
  Speaker 1: on the latter part of describing light as as waves
• 14:14
  Speaker 1: any electromagnetic field. And you're saying that we can with
• 14:18
  Speaker 1: that description of light, we can tell what happens when
• 14:21
  Speaker 1: it hits different things. Yeah, that's right. We think about
• 14:24
  Speaker 1: light is a little packet of energy, a little pulse
• 14:26
  Speaker 1: in the electromagnetic field propagating through the universe. So you
• 14:29
  Speaker 1: imagine like light coming out of the star and flying
• 14:32
  Speaker 1: through space and making it through the atmosphere and hitting
• 14:34
  Speaker 1: your skin. And his first question was, like, what happens
• 14:38
  Speaker 1: to that photon? Right? Is it just like absorbed? Right? Well,
• 14:42
  Speaker 1: hopefully he's wearing sunscreen if he's out there in the sun,
• 14:45
  Speaker 1: and most of it will get refracted, refracted, reflected. But
• 14:50
  Speaker 1: maybe just step us through the basics, like what happens
• 14:53
  Speaker 1: when one of these packets of energy in the electromagnetic
• 14:56
  Speaker 1: field runs into a matter particle like an electron on
• 15:00
  Speaker 1: or maybe like an atom, like the atoms and the skin.
• 15:02
  Speaker 1: What's going on? So if you want to think about
• 15:04
  Speaker 1: in terms of an individual particle of light, then you
• 15:06
  Speaker 1: can imagine like the photon flying through space and it
• 15:09
  Speaker 1: hits the matter. Matter, of course, is made of other
• 15:12
  Speaker 1: little particles, and so the photon interacts with that matter.
• 15:15
  Speaker 1: It's not like the photon hits your skin as a
• 15:17
  Speaker 1: whole big blob. It touches like one particle of your skin.
• 15:21
  Speaker 1: It would like zero in on a single electron in
• 15:25
  Speaker 1: an atom on the surface of your skin and interact
• 15:28
  Speaker 1: with that electron. And one thing that it can do,
• 15:30
  Speaker 1: for example, is it can be absorbed by that electron.
• 15:33
  Speaker 1: Electrons can just eat photons, and then that electron now
• 15:37
  Speaker 1: has the energy of that photon. Yeah, that's pretty well.
• 15:40
  Speaker 1: Although you said that the photon touches a matter particle
• 15:43
  Speaker 1: in your skin, but that's not actually true, right, or
• 15:46
  Speaker 1: at least the idea of things touching each other is
• 15:49
  Speaker 1: kind of controversial or philosophical. Really, what happens is that
• 15:53
  Speaker 1: they get close enough to each other where they have
• 15:56
  Speaker 1: some kind of quantum interaction. Right. Well, the quantum interaction
• 15:59
  Speaker 1: here is two fields coupling directly, Like you have the
• 16:02
  Speaker 1: electron field and the photon field, and they overlap in
• 16:06
  Speaker 1: space and energy passes from one field to another. That's
• 16:10
  Speaker 1: the fundamental way we describe an interaction is passing of
• 16:12
  Speaker 1: energy from one field to another. If you're talking about
• 16:15
  Speaker 1: two matter particles like two electrons, Yeah, they don't actually
• 16:18
  Speaker 1: touch because they communicate through a photon. Right, So two
• 16:21
  Speaker 1: electrons don't push against each other directly. They pass photons
• 16:25
  Speaker 1: back and forth. But a photon interacts directly with an electron.
• 16:28
  Speaker 1: Its energy flows from the electromagnetic field into the electron field, right,
• 16:33
  Speaker 1: But I guess I mean like that there's no actual touching.
• 16:35
  Speaker 1: It's just that the one wiggle gets close enough to
• 16:37
  Speaker 1: the other wiggle where they somehow, through the magic of
• 16:39
  Speaker 1: the universe, the energy gets transferred from one field to
• 16:42
  Speaker 1: the other. I guess that's what touching is, right. So
• 16:45
  Speaker 1: then now we're in a philosophy podcast again. But that's
• 16:48
  Speaker 1: an interesting way to think about it, is that it's
• 16:50
  Speaker 1: it's like energy going from the photon field to the
• 16:55
  Speaker 1: electron field, right, Like that just magically happens. Is there
• 16:58
  Speaker 1: there's no conduit, there's no channel for that to happen.
• 17:01
  Speaker 1: That just automatically happens. These fields are sort of like, uh,
• 17:04
  Speaker 1: kind of on top of each other in that way. Yeah,
• 17:06
  Speaker 1: as you said, space is filled with these quantum fields.
• 17:09
  Speaker 1: Is a bunch of them. Is one for electrons, is
• 17:11
  Speaker 1: one for quarks, is one for photons, is one for
• 17:13
  Speaker 1: every kind of particle. A lot of those fields ignore
• 17:16
  Speaker 1: each other, but some of the fields don't. Some of
• 17:18
  Speaker 1: the fields do talk to each other. We call that
• 17:20
  Speaker 1: a coupling, and that coupling is determined by the charges
• 17:23
  Speaker 1: of the particles. So, for example, the photon field can
• 17:27
  Speaker 1: pass energy to any field. For a particle that has
• 17:29
  Speaker 1: an electric charge, that's actually kind of what it means
• 17:32
  Speaker 1: to have an electric charge. So yeah, the energy can
• 17:34
  Speaker 1: pass directly from the photon field to the electron field.
• 17:38
  Speaker 1: Like mathematically, when we describe these fields, we write them
• 17:41
  Speaker 1: down together in the lagrange and of the standard model,
• 17:43
  Speaker 1: and we add a term in front of them which
• 17:45
  Speaker 1: is not zero, which means that energy can pass from
• 17:48
  Speaker 1: one field to the other. So when the photon flies
• 17:51
  Speaker 1: out of the sun and hits your skin, that energy
• 17:53
  Speaker 1: is propagating through the electromagnetic field and now into the
• 17:57
  Speaker 1: electron field. It's absorbed by the electron. Okay, so that's
• 18:00
  Speaker 1: one thing that can happen to the photon. It can
• 18:02
  Speaker 1: get absorbed by the electron, and then after that a
• 18:06
  Speaker 1: couple of other things can happen. Right. Yeah, it's possible
• 18:08
  Speaker 1: for that electron to then release that energy like back
• 18:11
  Speaker 1: into the photon field. Right. That's a two directional interaction.
• 18:15
  Speaker 1: Electrons can eat photons, They can also create photons. They
• 18:18
  Speaker 1: can spit photons out. That electron, for example, has a
• 18:21
  Speaker 1: bunch of energy now, and the universe doesn't like to
• 18:24
  Speaker 1: have energy density very high in one place. It likes
• 18:26
  Speaker 1: to relax, likes to roll down to lower potential energy.
• 18:30
  Speaker 1: So the electron, one thing you can do is jump
• 18:32
  Speaker 1: back down in energy and give off a photon again.
• 18:35
  Speaker 1: And that can happen lots of different ways. You can
• 18:37
  Speaker 1: call that reflection, you can call that fluorescence. But that's
• 18:40
  Speaker 1: one thing that the bit of matter can do is
• 18:42
  Speaker 1: they can spit that photon back out into the universe. Yeah.
• 18:46
  Speaker 1: I guess there's two interesting things about that. One is that,
• 18:48
  Speaker 1: first of all, the original photon is basically god right,
• 18:52
  Speaker 1: like when we think of light bouncing off of a
• 18:55
  Speaker 1: mirror or bouncing off of your skin, like, Actually, what's
• 18:58
  Speaker 1: happening is that the photon die is right, It disappears
• 19:01
  Speaker 1: into that electron, and then a neil photon gets split
• 19:04
  Speaker 1: out by that electron. You know, you keep saying we're
• 19:07
  Speaker 1: not a philosophy podcast, and then you keep asking philosophy
• 19:09
  Speaker 1: questions like is the photon killed when it's absorbed? You know,
• 19:14
  Speaker 1: it's really interesting question, is it the same photon? Well,
• 19:17
  Speaker 1: that photon didn't exist for a moment. It was absorbed
• 19:20
  Speaker 1: into the electron. It's quantum information still exists, right, It's
• 19:24
  Speaker 1: certainly correlated with the original photon, So it's not like
• 19:27
  Speaker 1: there's no relationship between the new photon and the old photon.
• 19:31
  Speaker 1: But yeah, you might say it's a new photon, it's
• 19:33
  Speaker 1: not the same one, I guess. I mean, like in
• 19:35
  Speaker 1: your views of physicists, is that like an actual sequence
• 19:38
  Speaker 1: of events, Like the photon got absorbed, the electron realized
• 19:43
  Speaker 1: it had too much energy, so then it powered down
• 19:45
  Speaker 1: and spit out a new photon, Like, is there a
• 19:49
  Speaker 1: certain amount of time that happens in and it was
• 19:51
  Speaker 1: certain order in which it happens. It's not an instantaneous process, right.
• 19:56
  Speaker 1: The electron can absorb a photon and can hold onto
• 19:59
  Speaker 1: it for a little while, and then it can give
• 20:00
  Speaker 1: it up later with a podcast episode about that process.
• 20:03
  Speaker 1: It's called fluorescence, and that can be quite delayed, and
• 20:06
  Speaker 1: there certainly can be a time gap. On the other hand,
• 20:09
  Speaker 1: sometimes the electron gives it up almost immediately, and it's
• 20:12
  Speaker 1: more like the photon bounces off of the electron. For example,
• 20:15
  Speaker 1: in a mirror. What happens is that the photon is
• 20:18
  Speaker 1: basically just immediately reflected, though it is momentarily held by
• 20:22
  Speaker 1: the electron. And it's important to consider the other things
• 20:25
  Speaker 1: that can happen. It's not necessarily the case that the
• 20:28
  Speaker 1: electron gives up that photon. There are other options. It
• 20:31
  Speaker 1: can pass that energy to the nucleus of the atom
• 20:34
  Speaker 1: or into the lattice of the material, basically heating it up.
• 20:37
  Speaker 1: So there's a few varieties of things that can happen
• 20:39
  Speaker 1: to the electron after it's absorbed the photon. All right, man,
• 20:43
  Speaker 1: maybe walk us through a little bit of those options.
• 20:46
  Speaker 1: So how does it impart energy to the nucleus. So
• 20:49
  Speaker 1: the electron is interacting with the nucleus in the same
• 20:52
  Speaker 1: way the electron can interact with the photon, right, it's
• 20:54
  Speaker 1: bound to the nucleus, and it's also interacting with other
• 20:58
  Speaker 1: electrons in the material. And so in the same way
• 21:01
  Speaker 1: that it can like give up a photon, it can
• 21:03
  Speaker 1: also bump up against other electrons or can push up
• 21:06
  Speaker 1: against the nucleus. All of these, of course would be
• 21:08
  Speaker 1: mediated by other virtual photons. But basically, instead of just
• 21:12
  Speaker 1: giving up that photon back out into space, it can
• 21:15
  Speaker 1: create a photon which is absorbed by like the next
• 21:17
  Speaker 1: atom or by another particle, and that particle can have
• 21:21
  Speaker 1: that energy in terms of like its vibration or its rotation.
• 21:24
  Speaker 1: There's lots of ways for energy to be stored in matter,
• 21:27
  Speaker 1: and once the electron has absorbed that photon, it's possible
• 21:31
  Speaker 1: for that photon to get into like many of these
• 21:32
  Speaker 1: different kinds of buckets. All right, well, let's get into
• 21:35
  Speaker 1: some of the examples of what like does as it
• 21:38
  Speaker 1: hits different materials and whether or not it dies or not.
• 21:42
  Speaker 1: But first let's take a quick break. All right, we're
• 21:56
  Speaker 1: answering listener questions today, and our first one was about
• 22:00
  Speaker 1: light and basically what happens when light hits stuff, and
• 22:04
  Speaker 1: we talked about how it's actually photons in the electromagnetic
• 22:07
  Speaker 1: field hitting the particles in the atoms of the things
• 22:11
  Speaker 1: that you're trying to shed a light on. And one
• 22:14
  Speaker 1: thing it can do, it can be reflected back, or
• 22:16
  Speaker 1: it can the electrons can spit out basically an identical
• 22:20
  Speaker 1: photon back in the same direction or sort of the
• 22:23
  Speaker 1: same direction that the initial photon came in at. But
• 22:26
  Speaker 1: you're saying, you could also absorb that photon and you know,
• 22:30
  Speaker 1: give the atom more energy or the material it hit
• 22:32
  Speaker 1: more energy. That's kind of what happens when you you're
• 22:35
  Speaker 1: sitting out in the sun heating up right. Yeah, that
• 22:38
  Speaker 1: energy comes from the sun via photons and gets absorbed
• 22:41
  Speaker 1: by your body. When you feel hot, that's because the
• 22:44
  Speaker 1: atoms in your body are moving faster, they're wiggling or
• 22:47
  Speaker 1: sliding around faster, and then energy comes from the photon.
• 22:51
  Speaker 1: So yeah, that photon is now like gone. You know,
• 22:54
  Speaker 1: maybe every time you sit in the sun you need
• 22:55
  Speaker 1: to have like ten to the twenty six funerals for
• 22:58
  Speaker 1: all the photons that you're killing. Yeah, it's pretty sad.
• 23:01
  Speaker 1: You sound really sad. That's why you should cover yourself
• 23:04
  Speaker 1: in a liminum foil or mirrors, or just never go
• 23:07
  Speaker 1: outside your house. That's right. If you want to be
• 23:08
  Speaker 1: a photo vegan, that's right, you can join the Society
• 23:12
  Speaker 1: for the Humane Treatment of Photons. But so that's I
• 23:15
  Speaker 1: guess that's reflection and that's absorption. What about refraction, like
• 23:20
  Speaker 1: he asked, like, what happens when the light hits like
• 23:23
  Speaker 1: a semi opaque window like in his camper or you know,
• 23:27
  Speaker 1: something that's translucent. Maybe what's what's going on there? How
• 23:31
  Speaker 1: does refraction work? So refraction is complicated. To understand from
• 23:34
  Speaker 1: this like microphysical picture of a single article, then you
• 23:38
  Speaker 1: have to back up and really remember that the path
• 23:40
  Speaker 1: of a photon is determined by the wave equations that
• 23:44
  Speaker 1: are guiding its motion through the electromagnetic field. Refraction is
• 23:48
  Speaker 1: very familiar wave phenomena. When a wave hits another kind
• 23:51
  Speaker 1: of material, part of it reflects, part of it gets transmitted,
• 23:55
  Speaker 1: and then it gets bent in a slightly different direction.
• 23:57
  Speaker 1: For example, if you have a straw in new glass
• 23:59
  Speaker 1: of water, looks like the straw sort of broken in
• 24:01
  Speaker 1: half because the part of the light that's going through
• 24:04
  Speaker 1: the water gets bent slightly in a new directions. That's
• 24:07
  Speaker 1: what we call refraction, and that's tricky to understand for
• 24:10
  Speaker 1: like the path of an individual photon, but it's very
• 24:13
  Speaker 1: straightforward from like the mathematics of the wave equation. So
• 24:16
  Speaker 1: what's going on? Then? Why does lighter any wave change
• 24:20
  Speaker 1: direction when it changes the medium it's going in. So
• 24:23
  Speaker 1: when a wave travels through a medium, it's like wiggling
• 24:26
  Speaker 1: something right, and different kinds of medium wiggle in different ways. So,
• 24:31
  Speaker 1: for example, if you shout in the air and then
• 24:33
  Speaker 1: that sound wave hit water, part of it reflects and
• 24:36
  Speaker 1: part of it goes into the water and changes direction,
• 24:38
  Speaker 1: But it gets fundamentally transformed when it goes into the water.
• 24:42
  Speaker 1: Right now, it's wiggling water molecules instead of wiggling air molecules.
• 24:46
  Speaker 1: In order to balance all the frequencies at the surface
• 24:48
  Speaker 1: to make the math add up at the surface, so
• 24:50
  Speaker 1: everything is like making sense and being continuous. Those waves
• 24:54
  Speaker 1: sort of have to change direction in order to account
• 24:57
  Speaker 1: for the fact that it's like a new kind of wave.
• 25:00
  Speaker 1: That's the fundamental physics of like refraction of waves for light.
• 25:03
  Speaker 1: It's a little bit complicated if you want to think about,
• 25:05
  Speaker 1: like what happens to one photon when it hits the
• 25:07
  Speaker 1: surface of the water. How does it know how much
• 25:10
  Speaker 1: to bend right? And that's determined by the wave equation.
• 25:13
  Speaker 1: That's why it's fundamentally quantum mechanical. Two photons hitting a
• 25:17
  Speaker 1: surface might bend in slightly different directions, but a bunch
• 25:20
  Speaker 1: of photons hitting the surface sort of average out to
• 25:23
  Speaker 1: give you the answer you would expect from the wave equations.
• 25:26
  Speaker 1: But I guess what, like, what's happening to the individual photon,
• 25:29
  Speaker 1: how does it change direction? For example, you can't really
• 25:32
  Speaker 1: ask the question what happens to an individual photon unless
• 25:36
  Speaker 1: you're actually observing, unless you're seeing it. You can only
• 25:38
  Speaker 1: really think about photons as particles when you're observing them.
• 25:42
  Speaker 1: So you shoot a photon out, it hits the surface
• 25:44
  Speaker 1: of the water, then you detect it somewhere in the water, right,
• 25:47
  Speaker 1: and you want to know, like what happened at the
• 25:49
  Speaker 1: surface of the water. That's like going to the double
• 25:52
  Speaker 1: slit experiment and asking like which slit did the photon
• 25:55
  Speaker 1: go through? Really, the photon has many possible paths between
• 26:00
  Speaker 1: the source of the light and where you're detecting it,
• 26:02
  Speaker 1: and quantum mechanically speaking, it does all of them together. Right.
• 26:06
  Speaker 1: There's not a single story for what happened to that
• 26:09
  Speaker 1: individual photon, right, But I guess it's a little bit
• 26:12
  Speaker 1: different because to the photon, it didn't change mediums, right,
• 26:16
  Speaker 1: Like it didn't change how it was. The electromagnetic field
• 26:20
  Speaker 1: didn't change between outside the water and inside the water. Right.
• 26:23
  Speaker 1: To a photon is just going through the electromagnetic field.
• 26:25
  Speaker 1: The difference is that it's suddenly surrounded by a bunch
• 26:28
  Speaker 1: of water molecules, right, And so are you saying, like
• 26:32
  Speaker 1: all those water molecules basically act like little double slits. Yeah,
• 26:36
  Speaker 1: all those water molecules are like little interactions. How do
• 26:39
  Speaker 1: water molecules change the path of the wave. Well, remember
• 26:43
  Speaker 1: that the water molecules are charged particles, so they interact
• 26:47
  Speaker 1: with the photon field. You know. One way to think
• 26:49
  Speaker 1: about it is that like the photon is getting pulled
• 26:52
  Speaker 1: on by all those molecules. But you can't really have
• 26:54
  Speaker 1: like a single picture of the path of an individual
• 26:57
  Speaker 1: photon and say this one got bent in this particugular way.
• 27:00
  Speaker 1: There's lots of different possibilities for what might happen to
• 27:03
  Speaker 1: the photon when it goes through, and one photon will
• 27:05
  Speaker 1: go in one direction, another in the other direction. If
• 27:08
  Speaker 1: you average up over many many photons, millions of photons,
• 27:11
  Speaker 1: then you'll get this sort of average behavior you expect
• 27:14
  Speaker 1: from a classical wave. But for an individual particle, it's
• 27:17
  Speaker 1: a little bit random. Because I guess the photon from
• 27:21
  Speaker 1: its point of view, it's like it's going along. Suddenly
• 27:23
  Speaker 1: it sees a wall of water molecules, and some of
• 27:26
  Speaker 1: those molecules bounce it this way or bounce it that
• 27:28
  Speaker 1: way or right. Is that what you're saying, m Yeah, exactly.
• 27:32
  Speaker 1: And when you say bounce it you mean reflection. Yeah,
• 27:35
  Speaker 1: we mean interaction, which of course means like absorption and
• 27:38
  Speaker 1: re emission, and I guess the angle of that reflection
• 27:42
  Speaker 1: will change because the water molecules are you know, in
• 27:45
  Speaker 1: random pocisitions. And so you're saying the aggregate effect is
• 27:49
  Speaker 1: that it refracts light along a certain angle. M hmm, exactly.
• 27:54
  Speaker 1: It's the aggregate effect that's controlled by the wave equations.
• 27:57
  Speaker 1: It's maybe crisp is when you think about like reflection,
• 28:00
  Speaker 1: what happens when light hits a mirror, for example, Sure,
• 28:02
  Speaker 1: it gets absorbed by the atoms in the surface of
• 28:04
  Speaker 1: the mirror, but how do those atoms know what direction
• 28:08
  Speaker 1: to send the light? Out? Right? Light when it hits
• 28:11
  Speaker 1: the mirror doesn't just come off at any angle, comes
• 28:13
  Speaker 1: off at a very precise angle, like it bounces off
• 28:15
  Speaker 1: right following Snell's law. How do the atoms that absorbed
• 28:19
  Speaker 1: the photon know in what direction to send it? We
• 28:22
  Speaker 1: can't really answer that question from the particle point of view,
• 28:25
  Speaker 1: because you know, they don't really know. But there's a
• 28:28
  Speaker 1: lot of wave mechanics that are guiding what's happening to
• 28:30
  Speaker 1: the average photon. Because nobody's actually watching a single particle
• 28:34
  Speaker 1: absorbed that photon and re emit it. It's just like
• 28:38
  Speaker 1: an average process for many, many possible paths, and a
• 28:41
  Speaker 1: lot of those conflict and interfere, giving you overall the
• 28:45
  Speaker 1: photon being emitted in the right direction that's predicted sort
• 28:49
  Speaker 1: of by classical optics. Right, doesn't it all have to
• 28:52
  Speaker 1: do a lot with the crystals, right, and the order
• 28:56
  Speaker 1: of the things that you're shining a light on. Then
• 28:58
  Speaker 1: that's when you get something that can mirror, which bounces
• 29:00
  Speaker 1: things more neatly. Right, Mirrors do bounce things more neatly.
• 29:05
  Speaker 1: It has mostly to do with the conductivity properties of
• 29:08
  Speaker 1: the surface. Conductors are things that don't allow electric fields
• 29:12
  Speaker 1: very deep in them, have a bunch of electrons inside
• 29:14
  Speaker 1: them which rearrange themselves to like cancel out any electric field.
• 29:18
  Speaker 1: And so photons when they hit something that's like a mirror,
• 29:21
  Speaker 1: don't go very deep. They bounced right off the surface,
• 29:24
  Speaker 1: whereas things that are not mirrors, like your wall, which
• 29:26
  Speaker 1: is white which reflects a lot of light, doesn't act
• 29:29
  Speaker 1: like a mirror. Because the photons can get sort of
• 29:31
  Speaker 1: deeper in and interact with things further inside, and because
• 29:35
  Speaker 1: different photons will get different distances inside, they come out
• 29:38
  Speaker 1: a little bit scrambled. So images are, for example, scrambled
• 29:41
  Speaker 1: by a white wall, whereas they're not scrambled by a mirror,
• 29:44
  Speaker 1: because the mirror reflects everything basically from the very same depth,
• 29:47
  Speaker 1: which is right at the surface, right right, Well that's interesting, yeah,
• 29:51
  Speaker 1: but I mean it also has to do with the
• 29:52
  Speaker 1: surface sector, right, That's why you can polish things to
• 29:54
  Speaker 1: make them look shiny. Yeah, exactly, want a very flat surface.
• 29:57
  Speaker 1: So all the photons are bouncing off at the same instance,
• 30:00
  Speaker 1: and that's why conductors like silver or steel whatever make
• 30:03
  Speaker 1: good mirrors. All right, Well, I think that answers Matthew's
• 30:06
  Speaker 1: question what happens when photons hit stuff? The answer is
• 30:10
  Speaker 1: they die, Yeah, Daniel, I think that's our basic conclusion today. Yes,
• 30:15
  Speaker 1: every interaction is an absorption and a re emission, which
• 30:18
  Speaker 1: means the original photon is gone, baby gone. I mean,
• 30:23
  Speaker 1: it's we joke about it, but it's kind of true. Right,
• 30:26
  Speaker 1: like all light interactions reflection when something shining not shining
• 30:30
  Speaker 1: black white colors, you know, all that is uh in
• 30:34
  Speaker 1: every interaction. Every time light bounces off with something, it
• 30:37
  Speaker 1: dies and then it gets resurrected. I prefer to think
• 30:40
  Speaker 1: of it, it's like having children, because the original photon
• 30:43
  Speaker 1: is influencing the new photons certainly, man, And now you
• 30:46
  Speaker 1: get into whether photons are house photons reproduced? Is that
• 30:51
  Speaker 1: what you're I think that's gets into philosophical biological podcast right.
• 31:00
  Speaker 1: We only allow certain kinds of baseless philosophy on this show.
• 31:04
  Speaker 1: That's where we have standards here, only fantastic discussions here. Well,
• 31:10
  Speaker 1: thank you very much Matthew for that really intriguing question.
• 31:14
  Speaker 1: All right. Our next question comes from Tim and it
• 31:16
  Speaker 1: has to do with stars. Hey, Daniel and Core Hey,
• 31:21
  Speaker 1: I had a question. Is there such a thing as
• 31:24
  Speaker 1: a star that is so big or so bright that
• 31:29
  Speaker 1: it would actually affect the daytime nighttime cycles of planets
• 31:34
  Speaker 1: in a nearby solar system. I'm not talking about like
• 31:37
  Speaker 1: a binary solar system, talking about a star that is
• 31:41
  Speaker 1: in a neighboring system. Just listen to your podcasts about
• 31:46
  Speaker 1: twinkling stars and that made me thinking about it. Thanks
• 31:49
  Speaker 1: for the answers, because I know you'll have them. Well,
• 31:52
  Speaker 1: thank you Tim for that question and the faith that
• 31:54
  Speaker 1: you have that we will have answers. I come in
• 31:58
  Speaker 1: every time having the same confidence. Did you do well?
• 32:01
  Speaker 1: We'll definitely have something to say, even if we can't
• 32:03
  Speaker 1: answer the question definitively that's right, that's right. Anything techniquely
• 32:07
  Speaker 1: counts as an answer. I learned with my kids. When
• 32:09
  Speaker 1: questions hit the podcast, they die. That's right, to get absorbed,
• 32:14
  Speaker 1: and then we burth and back out into your ear.
• 32:18
  Speaker 1: We admit something. All right. Well, Tim's question is that
• 32:24
  Speaker 1: is it possible for a light from a different solar
• 32:27
  Speaker 1: system to affect the feeling of day and night in
• 32:31
  Speaker 1: a planet in another solar system? Right? That's the basic question. Yeah, Basically,
• 32:36
  Speaker 1: can stars change the day night pattern? Like? Could stars
• 32:39
  Speaker 1: be bright enough that they cause shadows? For example, I've
• 32:42
  Speaker 1: been out at night looking at but the stars and
• 32:45
  Speaker 1: then checking out behind me to see, like, am I
• 32:47
  Speaker 1: casting a star shadow? Star shadow? Sounds like a good
• 32:50
  Speaker 1: gamer tag. But of course, as you look up at
• 32:54
  Speaker 1: the night sky, those stars are obvious to your eyes,
• 32:56
  Speaker 1: but they're not bright enough to make the night sky
• 33:00
  Speaker 1: bright right, to make it feel like it's daytime? Well,
• 33:03
  Speaker 1: technically they do cast. You do cast a star shadow, right,
• 33:06
  Speaker 1: or a shadow star right? Like the technically, yeah, you
• 33:09
  Speaker 1: are blocking light from stars and preventing something behind you
• 33:13
  Speaker 1: from getting that light. Yeah, And it's fundamentally the same
• 33:16
  Speaker 1: process as getting a shadow from our sun. It's just
• 33:19
  Speaker 1: that our sun is closer, right, and so it's brighter,
• 33:23
  Speaker 1: so you notice it much more because it does dominate
• 33:26
  Speaker 1: the brightness of our planet. And the thing I love
• 33:28
  Speaker 1: about Tim's question, he says he's wondering about these two
• 33:30
  Speaker 1: different categories, our sun and the distant stars, and wondering
• 33:34
  Speaker 1: if there's something that bridges them. Is it's possible to
• 33:37
  Speaker 1: have something in between other stars that are close enough
• 33:40
  Speaker 1: to be sort of like part of our day night cycle.
• 33:42
  Speaker 1: Really cool way to think about it. I guess maybe
• 33:44
  Speaker 1: the question is like, how close can two solar systems
• 33:46
  Speaker 1: get so that one sun actually changes the day night
• 33:50
  Speaker 1: time feeling of another solar system? Yeah? Maybe Tim's working
• 33:53
  Speaker 1: on a science fiction novel, and this is an important
• 33:55
  Speaker 1: part of the plot, Right, isn't everybody working on a
• 33:57
  Speaker 1: science fic novel? I don't know. I feel like science
• 34:00
  Speaker 1: fiction gets absorbed by the reader and then not always
• 34:02
  Speaker 1: re emitted as a new novel. Right. Sometimes science fiction
• 34:06
  Speaker 1: novels just die. I see, they die in the reader's brain.
• 34:11
  Speaker 1: Maybe the reader just goes to an excited state of
• 34:14
  Speaker 1: knowledge and enlightenment. Oh there you go, transforms that energy
• 34:17
  Speaker 1: into you know, their their own work, their own imagination.
• 34:22
  Speaker 1: But anyway, here we are not answering Tim's question once again, Yes,
• 34:26
  Speaker 1: but we are trying to hear and um So, I
• 34:28
  Speaker 1: guess the question is how far canto solar systems get
• 34:31
  Speaker 1: before maybe they're not two different solar systems. I wonder
• 34:35
  Speaker 1: if that's kind of part of the question. Yeah, because
• 34:37
  Speaker 1: he specifically ruled out like a binary solar system where
• 34:39
  Speaker 1: you have two stars. It's a really interesting question and
• 34:42
  Speaker 1: there's a couple of different parameters we can play with here.
• 34:45
  Speaker 1: One is where you are in the galaxy, which really
• 34:48
  Speaker 1: determines how far apart stars are, and also how big
• 34:53
  Speaker 1: the stars are, because there's a huge variation in the
• 34:56
  Speaker 1: brightness and the size of stars. Right there are big ones,
• 35:00
  Speaker 1: small ones, and out in our neighborhood of the galaxy,
• 35:04
  Speaker 1: we're sort of like halfway out from the center of
• 35:06
  Speaker 1: the galaxy. Things are not very tightly packed. We're sort
• 35:09
  Speaker 1: of like in the suburbs of the galaxy. Like the
• 35:12
  Speaker 1: closest star to Earth is about four light years away.
• 35:16
  Speaker 1: That's really really far away. And remember that the brightness
• 35:19
  Speaker 1: of a star gets dimmer as you get further away,
• 35:22
  Speaker 1: and it gets dimmer by that distance squared, So if
• 35:25
  Speaker 1: you're ten times further away, a star is a hundred
• 35:29
  Speaker 1: times dimmer. If you're a thousand times further away, then
• 35:32
  Speaker 1: it's a million times dimmer. So that mathematics really works
• 35:37
  Speaker 1: against the distant stars. It's why the Sun really dominates
• 35:40
  Speaker 1: our experience. Yeah, and it's why if we were ten
• 35:43
  Speaker 1: times closer to the Sun, we would feel it's heat
• 35:46
  Speaker 1: a million times more, right, we need toast. Yeah, and
• 35:50
  Speaker 1: in our neighborhood the stars are pretty diffused, but if
• 35:53
  Speaker 1: you go to the center of the galaxy, things are
• 35:55
  Speaker 1: much more cozy. Right in the center of the galaxy,
• 35:59
  Speaker 1: it's not uncommon to have stars that are less than
• 36:01
  Speaker 1: a light year apart, or even less than a tenth
• 36:04
  Speaker 1: of a light year apart, And so those stars benefit
• 36:07
  Speaker 1: from that short distance. They get the same math, but
• 36:10
  Speaker 1: working in their favor to boost their brightness. You're ten
• 36:13
  Speaker 1: times closer, now you're a hundred times brighter. To give
• 36:16
  Speaker 1: you a sense of like what that means, if we
• 36:18
  Speaker 1: had another star as bright as our sun that was
• 36:21
  Speaker 1: like half a light year away, we would see it
• 36:24
  Speaker 1: during the daytime. It would be like bright enough in
• 36:26
  Speaker 1: our sky to see during the daytime, be about as
• 36:29
  Speaker 1: bright as venuses, which you can see during the daytime.
• 36:32
  Speaker 1: So like we would look up into the day sky
• 36:35
  Speaker 1: and maybe among the clouds you would see a little
• 36:38
  Speaker 1: pinpoint of light. Yeah, you'd see a pinpoint. It wouldn't
• 36:41
  Speaker 1: change the day night cycle, right, you could see it
• 36:43
  Speaker 1: during the day of the way you can see the moon,
• 36:45
  Speaker 1: but doesn't mean that the night would feel like the day,
• 36:48
  Speaker 1: but it would be something that's visible. So you could
• 36:50
  Speaker 1: see another sun that was like point forward light years away,
• 36:54
  Speaker 1: you know, if it was even closer than it would
• 36:56
  Speaker 1: be even brighter and in the center of the galaxy.
• 36:58
  Speaker 1: That does happen stars very close together, But I guess
• 37:01
  Speaker 1: at what point does it become part of a binary system?
• 37:05
  Speaker 1: You know, like how close can two stars get without
• 37:07
  Speaker 1: them basically being the same in affecting each other gravitationally,
• 37:12
  Speaker 1: so that they become one big solar system. Well, stars
• 37:15
  Speaker 1: are always going to pull on each other gravitationally, right,
• 37:18
  Speaker 1: we are getting pulled on by our neighboring stars even
• 37:21
  Speaker 1: though they are four light years away, and our galaxy
• 37:24
  Speaker 1: is getting pulled on by the neighboring galaxy even though
• 37:26
  Speaker 1: it's millions of light years away. So it's just sort
• 37:29
  Speaker 1: of like a cosmic web of gravitational interactions. And in
• 37:33
  Speaker 1: the center of the galaxy, these stars are all tugging
• 37:35
  Speaker 1: on each other, but they're not like in stable orbits
• 37:38
  Speaker 1: around each other. I think for a binary star system
• 37:41
  Speaker 1: you want them to be like gravitationally captured by each other.
• 37:44
  Speaker 1: But it's more like a mosh pit than a bunch
• 37:46
  Speaker 1: of dancing couples in the center of the galaxy. It's
• 37:48
  Speaker 1: kind of crazy down there. So I guess if you're
• 37:51
  Speaker 1: close to the center of the galaxy, uh, there's not
• 37:53
  Speaker 1: just probably one star that's have a light year a way.
• 37:56
  Speaker 1: There's a Brazilian stars that are light your way. So
• 37:59
  Speaker 1: if our solar system was and near the center of
• 38:02
  Speaker 1: the galaxy, we would look up at the day sky
• 38:04
  Speaker 1: and it would be filled with pinpoints, right, maybe just
• 38:07
  Speaker 1: a huge cloud that it would all just kind of
• 38:10
  Speaker 1: be super bright everywhere. Yeah, exactly. And it wouldn't be
• 38:14
  Speaker 1: unreasonable that your night sky might have a very very
• 38:18
  Speaker 1: bright star in it. You might have a neighbor which
• 38:20
  Speaker 1: is pretty close and just the same way, when you're
• 38:23
  Speaker 1: trying to sleep, if your neighbor has like floodlights on
• 38:25
  Speaker 1: in their house, it can go through your windows and
• 38:27
  Speaker 1: disturb your sleep. Near the center of the galaxy, you
• 38:30
  Speaker 1: might have a neighboring star that's bright enough to disturb
• 38:33
  Speaker 1: your night, especially if that neighboring star is not like
• 38:36
  Speaker 1: the Sun, if it's one of the big monster stars.
• 38:39
  Speaker 1: Because stars have a huge variation in their brightness. You know,
• 38:43
  Speaker 1: our sun is britty bright, but there are many more
• 38:46
  Speaker 1: stars out there that are much much brighter than our sun. Right,
• 38:49
  Speaker 1: I guess it's all relative, right, Like what what we
• 38:52
  Speaker 1: consider daytime here might be equivalent to nighttime on a
• 38:56
  Speaker 1: planet near the center of the galaxy, right, just from
• 38:58
  Speaker 1: all the life from all the by stars. Yeah, potentially, Yeah,
• 39:02
  Speaker 1: that's true exactly, And just to give you a sense
• 39:04
  Speaker 1: of the range, you know, like in our night sky,
• 39:07
  Speaker 1: there are other stars we can see that are much brighter.
• 39:09
  Speaker 1: Like Serious is a star in our sky, and it's
• 39:11
  Speaker 1: twenty five times as bright as the Sun. If you're
• 39:14
  Speaker 1: at the same distance from Serious as you were from
• 39:16
  Speaker 1: the Sun, it would be twenty five times as bright.
• 39:20
  Speaker 1: But that's just like a little step up. There are
• 39:22
  Speaker 1: other stars, like the biggest stars in our galaxy, one
• 39:25
  Speaker 1: is called Eta Carina, that are like two million times
• 39:29
  Speaker 1: as bright as the Sun two million, and so any
• 39:33
  Speaker 1: star in the neighborhood of Eta Carina is basically going
• 39:36
  Speaker 1: to be bright all night long. Yeah, And I guess
• 39:40
  Speaker 1: it also opens the possibility that like that, like maybe
• 39:42
  Speaker 1: if you're a planet orbiting a dim star, like maybe
• 39:46
  Speaker 1: like a brown dwarf or something that's just kind of simmering,
• 39:50
  Speaker 1: they're not really shining as bright as our sun. Then
• 39:53
  Speaker 1: for you, if you are near the center of the galaxy,
• 39:56
  Speaker 1: then really your son maybe doesn't even influence the day
• 40:00
  Speaker 1: a night cycle, right, Like maybe for you in that
• 40:02
  Speaker 1: Solar system, day and night is when your planet's facing
• 40:06
  Speaker 1: the center of the galaxy or not facing the center
• 40:08
  Speaker 1: of the gap, right, Like a day could be like
• 40:11
  Speaker 1: a whole year. Yeah, and the darkest times could be
• 40:14
  Speaker 1: when your son who clips is the other bright neighbor,
• 40:16
  Speaker 1: so you can have like a star star eclipse. Wow. Yeah,
• 40:19
  Speaker 1: who said science fiction dies? On this podcast, we're not
• 40:24
  Speaker 1: just absorbing science fiction here. We are emitting it in
• 40:27
  Speaker 1: real time. We are creating it. You're redirecting it. We
• 40:32
  Speaker 1: are reflecting these ideas back again. We want to hear
• 40:34
  Speaker 1: this story. Send us the draft of your novel when
• 40:36
  Speaker 1: you finished it. Yeah, but make sure we sign an
• 40:39
  Speaker 1: NDA here. I wouldn't trust us not to copy your ideas. Copy.
• 40:43
  Speaker 1: We're collaborators, we're co authors, we're here workshopping it live man.
• 40:47
  Speaker 1: All right, well, thank you Dann for that awesome question. Um,
• 40:50
  Speaker 1: I guess the answer is yes, there could be stars
• 40:54
  Speaker 1: so bright that they do affect the night day time cycle.
• 40:57
  Speaker 1: And in fact, if you're closer far away from the
• 41:00
  Speaker 1: center of the galaxy, it might make an bigger or
• 41:03
  Speaker 1: smaller difference. Yeah, the whole definition of day and night
• 41:05
  Speaker 1: would be really different, and it would lead to really
• 41:08
  Speaker 1: complicated patterns of life on that planet, which could be
• 41:11
  Speaker 1: really fun to explore in Tim's future debut science fiction novel,
• 41:14
  Speaker 1: Tim Jorgan Daniels new debut. Right, yes, of course, in fact,
• 41:20
  Speaker 1: you did he go first on the author list. I
• 41:22
  Speaker 1: don't know. We'll take that question off the air. All right,
• 41:28
  Speaker 1: let's get into our last question here about black holes
• 41:30
  Speaker 1: that are maybe made out of dark matter. We'll jump
• 41:34
  Speaker 1: right into that hole, but first let's take another quick break.
• 41:50
  Speaker 1: All right, we're answering listener questions and also stealing their ideas.
• 41:54
  Speaker 1: Apparently we're interacting with them, and we're interacted. I see,
• 42:01
  Speaker 1: that's right. The universe is not a criminal it's just
• 42:04
  Speaker 1: very interactive. That's right. The podcast host Field is interacting
• 42:08
  Speaker 1: with the podcast listener Field. Right, there's a couple and
• 42:10
  Speaker 1: there's a charge there. I can feel it. Yes, I
• 42:13
  Speaker 1: didn't still any classified documents. I just interacted with them
• 42:16
  Speaker 1: in my private home. Let's hope we don't get charged officially. Alright.
• 42:21
  Speaker 1: Our last question here comes from Matteo's and it's about
• 42:24
  Speaker 1: black holes. Hello, Daniel and Jorge, this is Mats from Poland.
• 42:28
  Speaker 1: I was wondering about the possibility of having a black
• 42:30
  Speaker 1: hole made entirely from the dark matter. I understand that
• 42:33
  Speaker 1: it's unlikely to happen because of the dark matter properties,
• 42:36
  Speaker 1: but I was wondering how could we detect one if
• 42:39
  Speaker 1: we can measure the black holes electric charge. Would a
• 42:42
  Speaker 1: zero charge mean that there is no normal matter inside?
• 42:45
  Speaker 1: How likely would it be for a black hole to
• 42:47
  Speaker 1: have zero electric charge? This also has led me to
• 42:51
  Speaker 1: some more general questions. Is the total electric charge in
• 42:53
  Speaker 1: the universe equal to zero? How about on galaxy or
• 42:57
  Speaker 1: planet level? I'm eager to hear your answers to my questions.
• 43:00
  Speaker 1: Thanks a lot for your great work with the podcast.
• 43:03
  Speaker 1: All right, thank you Matteos for that great question, and
• 43:05
  Speaker 1: it came to us free of charge, as all questions do. Now,
• 43:10
  Speaker 1: this is an interesting question he's asking. First of all, well,
• 43:13
  Speaker 1: he's asking several questions, but the first one was what
• 43:16
  Speaker 1: would happen if a black hole was made entirely out
• 43:21
  Speaker 1: of dark matter? He said, you know, he caveats that
• 43:24
  Speaker 1: it's unlike, he knows it's unlikely to happen. But what
• 43:27
  Speaker 1: if you made a black hole with dark matter? Would
• 43:30
  Speaker 1: it be different? Could? Could you tell the difference between
• 43:32
  Speaker 1: a regular black hole? Yeah? And even suggests a way
• 43:34
  Speaker 1: of maybe distinguishing dark matter black holes from a normal
• 43:38
  Speaker 1: matter black holes, which I thought was pretty clever. He's
• 43:40
  Speaker 1: thinking like a scientist. He's like, if this were to happen,
• 43:43
  Speaker 1: if I basically speculate about this, can this help me
• 43:46
  Speaker 1: write a ground Yeah? And so there's a bunch of
• 43:49
  Speaker 1: stuff going on here. First is the idea of what's
• 43:52
  Speaker 1: in a black hole? What can you make a black
• 43:54
  Speaker 1: hole out of? And you know, we think that black
• 43:57
  Speaker 1: holes can eat anything. They can eat normal matter, they
• 43:59
  Speaker 1: can eat dark matter, they can eat other black holes,
• 44:02
  Speaker 1: they can eat basically anything and grow because the curvature
• 44:05
  Speaker 1: space is determined not just by mass but by anything
• 44:09
  Speaker 1: with energy. That's what general relativity tells us. So black
• 44:12
  Speaker 1: holes can basically eat anything. You can make them out
• 44:15
  Speaker 1: of normal stuff or dark matter. But we think that
• 44:17
  Speaker 1: most black holes are probably dominated by normal matter because
• 44:21
  Speaker 1: it's harder for dark matter to fall into black holes. Mostly,
• 44:25
  Speaker 1: we think dark matter swirls around in big clouds, doesn't
• 44:29
  Speaker 1: clump together and fall into black holes as often as
• 44:32
  Speaker 1: normal matter. Right, because it's harder to make a black
• 44:35
  Speaker 1: hole out of dark matter, I think Matteo's kind of
• 44:38
  Speaker 1: acknowledged that they're harder to make and therefore less likely
• 44:42
  Speaker 1: to happen in the universe. But the basic answer is
• 44:45
  Speaker 1: that you can make a black hole out of dark matter. Like,
• 44:48
  Speaker 1: if you can somehow take dark matter squeeze it down
• 44:51
  Speaker 1: to a small enough radius, it would form a black hole.
• 44:53
  Speaker 1: In principle, absolutely yes, it would. And the reason that
• 44:56
  Speaker 1: it's harder to squeeze dark matter down is that we
• 44:59
  Speaker 1: don't think dark matter feels any other forces other than gravity,
• 45:03
  Speaker 1: so you can't push on it, for example, to compact.
• 45:05
  Speaker 1: It doesn't stick to itself, and that means it's hard
• 45:09
  Speaker 1: for it to give up angular momentum if it's spinning
• 45:11
  Speaker 1: around a black hole in the accretion disk, for example,
• 45:14
  Speaker 1: why do things fall into the black hole and not
• 45:16
  Speaker 1: just spin around them forever. They do that because they
• 45:19
  Speaker 1: lose angular momentum, They bump into something else in the
• 45:21
  Speaker 1: acreation disc and then head towards the black hole. Dark matter,
• 45:25
  Speaker 1: because it doesn't feel those forces we think, just passes
• 45:27
  Speaker 1: right through itself, doesn't bump into anything, doesn't stick together
• 45:31
  Speaker 1: into big blobs and fall into the black hole. But
• 45:33
  Speaker 1: it is possible if you somehow got a bunch of
• 45:36
  Speaker 1: dark matter together, it would make a black hole. Right,
• 45:38
  Speaker 1: And like also given enough time, right, Like, if you
• 45:41
  Speaker 1: have a blob of dark matter out in space, eventually
• 45:45
  Speaker 1: maybe in trillions of years, and it will all collapse
• 45:47
  Speaker 1: into a black hole. Right, that's right, Because rotation is acceleration,
• 45:51
  Speaker 1: which means it's giving off gravitational waves. So even something
• 45:55
  Speaker 1: that feels nothing else but gravity will eventually lose its
• 45:59
  Speaker 1: orbit because it's giving off energy out into the universe
• 46:02
  Speaker 1: and it will fall in. So, yes, eventually dark matter
• 46:05
  Speaker 1: will fall into a black hole, right, isn't there? I
• 46:08
  Speaker 1: mean there's a lot of dark matter out there in
• 46:10
  Speaker 1: the universe, a lot more than regular matter, and the
• 46:13
  Speaker 1: universe is pretty old, isn't it possible that at this
• 46:16
  Speaker 1: point some dark matter may have fallen and created a
• 46:19
  Speaker 1: dark matter black hole. It's almost certainly the case that
• 46:21
  Speaker 1: every black hole contains some dark matter. While a big
• 46:24
  Speaker 1: cloud is hard to collapse into a black hole, if
• 46:26
  Speaker 1: you have an existing black hole and a dark amoutter
• 46:29
  Speaker 1: of particle just like heads towards it, it's just going
• 46:31
  Speaker 1: to fall in. There's no like special protection. So every
• 46:34
  Speaker 1: black hole probably contains some dark matter. He's asking about,
• 46:37
  Speaker 1: like if it's possible to have a black hole that's
• 46:39
  Speaker 1: only dark matter, right, So imagine some big blob of
• 46:43
  Speaker 1: dark matter that's gotten separated from normal matter, which could happen,
• 46:47
  Speaker 1: right like the Bullet cluster collision stripped dark matter from
• 46:50
  Speaker 1: the normal matter in those galaxies, and of these big
• 46:53
  Speaker 1: vast clouds of dark matter basically all by themselves, wait
• 46:57
  Speaker 1: long enough, and that would collapse into a hole. Right.
• 47:00
  Speaker 1: He's asking, like, I think you're saying that, you know,
• 47:03
  Speaker 1: most black holes are like milk chocolate, you know, maybe
• 47:07
  Speaker 1: dark chocolate. But he's asking, can you have a dark
• 47:11
  Speaker 1: chocolate bark? Can you have a black hole made entirely
• 47:14
  Speaker 1: out of dark matter, and the answer is yes, right,
• 47:17
  Speaker 1: that can happen. The answer is yes, that can happen.
• 47:20
  Speaker 1: And then we have the question of like, how could
• 47:21
  Speaker 1: you tell? And now we run up against the problem,
• 47:24
  Speaker 1: which is that we can't know very much about what's
• 47:26
  Speaker 1: going on inside the black hole. The no hair theorem
• 47:29
  Speaker 1: tells us we can know the mass of the black hole,
• 47:31
  Speaker 1: basically how much stuff is in it. We can know
• 47:33
  Speaker 1: whether it's spinning, and we can know it's electric charge.
• 47:37
  Speaker 1: And that's the key that Mattheos is focusing on to
• 47:39
  Speaker 1: tell us whether or not the black hole is built
• 47:41
  Speaker 1: from dark matter or normal matter. Because if you take
• 47:44
  Speaker 1: a black hole and you throw electrons into it, you
• 47:46
  Speaker 1: can't tell what happens to those electrons once they pass in,
• 47:50
  Speaker 1: but it does change the overall electric charge of the
• 47:53
  Speaker 1: black hole, and you can measure that the same way
• 47:55
  Speaker 1: you can measure a black hole's mass increasing. You can
• 47:58
  Speaker 1: measure it's charge increasing or decreasing as you add charge
• 48:01
  Speaker 1: to it, because charge is conserved in our universe. But
• 48:05
  Speaker 1: how do you measure the charge of a black hole
• 48:08
  Speaker 1: if no information can come out? You can measure the
• 48:10
  Speaker 1: charge of a black hole the same way you measure
• 48:12
  Speaker 1: its mass, right, you measure the field it creates. Black
• 48:15
  Speaker 1: Holes can make gravitational fields that go past their event horizon,
• 48:19
  Speaker 1: and in the same way they can make electric fields
• 48:21
  Speaker 1: that go past their event horizon. You don't need information
• 48:24
  Speaker 1: to come out of the black hole in order for
• 48:27
  Speaker 1: that electric field to exist outside the black hole. Now,
• 48:30
  Speaker 1: I guess the question is that Mattes was thinking about.
• 48:34
  Speaker 1: It was that, you know, dark matter doesn't feel the
• 48:36
  Speaker 1: electromagnetic force. That's one of the things we know about it.
• 48:39
  Speaker 1: That's why it's invisible. You can't see it. So if
• 48:41
  Speaker 1: you made a black hole out of dark matter, does
• 48:44
  Speaker 1: that mean that the black hole wouldn't feel the electromagnetic force. Yeah,
• 48:49
  Speaker 1: that's true. If a black hole is made out of
• 48:51
  Speaker 1: dark matter, then it has no charge, and then it
• 48:54
  Speaker 1: wouldn't feel electromagnetism. An electron flew by a dark matter
• 48:58
  Speaker 1: black hole, it wouldn't feel any force, just the same
• 49:01
  Speaker 1: way it doesn't feel any force from any other neutral object. Well,
• 49:04
  Speaker 1: we will feel the force of gravity, it just wouldn't
• 49:06
  Speaker 1: feel the electromagnetic force. Right, Yes, it wouldn't feel any
• 49:08
  Speaker 1: electromagnetic force. It would only feel the gravity, just the
• 49:11
  Speaker 1: same way when it flies by any other neutral object.
• 49:15
  Speaker 1: It doesn't feel an electromagnetic force from it, only its gravity,
• 49:18
  Speaker 1: all right, So then I guess Matteos was thinking. If
• 49:20
  Speaker 1: that's true, then could we tell whether a black hole
• 49:24
  Speaker 1: is made out of dark matter or not by measuring
• 49:27
  Speaker 1: its charge? Like, if you see a black hole, you
• 49:29
  Speaker 1: measure its charge, you see that it's zero charge, or
• 49:31
  Speaker 1: that electrons are not affected by are not attracted or
• 49:35
  Speaker 1: repelled by this black hole. Would that be evidence that
• 49:38
  Speaker 1: this black hole is made out of dark match? Yeah,
• 49:40
  Speaker 1: And the last wrinkle there is to think about normal
• 49:43
  Speaker 1: matter black holes. Would they also have zero electric charge,
• 49:46
  Speaker 1: in which case you couldn't distinguish them from dark matter
• 49:49
  Speaker 1: black holes, or do they typically have some amount of
• 49:52
  Speaker 1: residual charge, in which case an exactly zero charge black
• 49:57
  Speaker 1: hole would be weird and would be a nice signal
• 50:00
  Speaker 1: of a dark matter black hole. So that's sort of
• 50:02
  Speaker 1: the last part of the question is how likely is
• 50:04
  Speaker 1: it for a normal matter black hole to have zero
• 50:06
  Speaker 1: electric charge? I see, So if a normal black hole
• 50:09
  Speaker 1: somehow in its formation aid more electrons than to say,
• 50:13
  Speaker 1: protons or positrons, then it would have an overall negative charge,
• 50:17
  Speaker 1: or if it ate didn't need enough electrons it would
• 50:21
  Speaker 1: have a positive charge. You're saying, maybe a zero charge
• 50:25
  Speaker 1: black hole wouldn't tell us that it's made out of
• 50:27
  Speaker 1: dark marror because it can also happen normally in a
• 50:30
  Speaker 1: black hole. It can't also happen normally, and it's a
• 50:33
  Speaker 1: bit of a probability thing. Black holes are just randomly
• 50:35
  Speaker 1: eating particles. What's the chances that it's exactly balanced that
• 50:39
  Speaker 1: it eats exactly as many positive particles as negative particles?
• 50:44
  Speaker 1: On one hand, is very unlikely to get exactly that balance.
• 50:47
  Speaker 1: On the other hand, is also the most likely outcome.
• 50:50
  Speaker 1: In the same way that like, if you flip a
• 50:52
  Speaker 1: coin a million times, what are the chances you're gonna
• 50:56
  Speaker 1: get exactly fifty percent heads and exactly fifty tails. Well,
• 51:00
  Speaker 1: it's unlikely to get exactly that number, it's also the
• 51:03
  Speaker 1: most likely outcome, right right. And also, I guess it
• 51:06
  Speaker 1: would be kind of hard to make a pure dark
• 51:08
  Speaker 1: matter black hole, right, Like, if you have a pure
• 51:11
  Speaker 1: dark matter black hole and one electron falls into it,
• 51:14
  Speaker 1: then suddenly it's got a charge. Yes, so that would
• 51:16
  Speaker 1: make this pretty challenging. But it is really interesting to
• 51:19
  Speaker 1: think about what is the charge distribution of black holes
• 51:22
  Speaker 1: out there in the universe. Are they all basically zero
• 51:25
  Speaker 1: or very close to zero? What is the overall charge
• 51:28
  Speaker 1: of these things? We have a whole episode planned about
• 51:30
  Speaker 1: the charge of the entire universe and the galaxy. But briefly,
• 51:34
  Speaker 1: most of the stuff that's out there is close to
• 51:37
  Speaker 1: neutral because the electromagnetic force is so strong that anything
• 51:41
  Speaker 1: that isn't neutralized, the force basically cancels it out. It
• 51:44
  Speaker 1: will like suck electrons off of something to balance it out.
• 51:48
  Speaker 1: Mostly like the Sun, for example, actually has a slight
• 51:51
  Speaker 1: charge because it's solar wind, has electrons and protons, but
• 51:56
  Speaker 1: it's easier for the electrons to escape the Sun than
• 51:58
  Speaker 1: protons because they have a lower mass. So the Sun
• 52:01
  Speaker 1: gives off more electrons and protons, so it has a
• 52:04
  Speaker 1: very slight positive charge. Interesting, I do agree the Sun
• 52:09
  Speaker 1: is a very positive influence on my life at least
• 52:12
  Speaker 1: for sure. I mean, it's not free of charge, but
• 52:15
  Speaker 1: I do have to wear some blood. So the answer
• 52:17
  Speaker 1: to this question, it's a really clever way to think
• 52:18
  Speaker 1: about what might be inside a black hole, but I
• 52:21
  Speaker 1: think be very challenging to prove that a black hole
• 52:24
  Speaker 1: is a dark matter, because it's possible to get zero
• 52:28
  Speaker 1: overall charge even without dark matter. Right. And also, I
• 52:32
  Speaker 1: guess it maybe points to this idea that black holes
• 52:34
  Speaker 1: are black holes, right, Like, even if it's dark matter
• 52:37
  Speaker 1: that falls into it, dark matter eventually just gets transformed
• 52:40
  Speaker 1: into pure energy. Right, So, like a black hole really
• 52:44
  Speaker 1: kind of grinds everything up and maybe makes it impossible
• 52:47
  Speaker 1: to tell if what you put in was dark matter
• 52:49
  Speaker 1: or not. Yeah, we don't know the quantum states of
• 52:51
  Speaker 1: the things inside the black hole. It's one of the
• 52:53
  Speaker 1: deepest questions in modern physics, like what is the form
• 52:56
  Speaker 1: of matter inside there? We don't know the answer because
• 52:59
  Speaker 1: we don't have a theory of quantum gravity. We don't
• 53:01
  Speaker 1: understand how gravity works for individual particles. So once the
• 53:05
  Speaker 1: dark matter is inside the black hole, it's not really
• 53:07
  Speaker 1: dark matter anymore. It's something weird and new that we
• 53:10
  Speaker 1: don't understand. Interesting. All right, Well, thank you mass for
• 53:14
  Speaker 1: that question. These were all pretty good questions, not really light.
• 53:19
  Speaker 1: They're pretty heavy and content. Last one is super extra heavy.
• 53:24
  Speaker 1: So for those of you on an intellectual diet, sorry
• 53:27
  Speaker 1: for the heavy meal. Hopefully we had expanded your brain
• 53:30
  Speaker 1: your waistline. But thank you for emitting these questions. These
• 53:33
  Speaker 1: particles of curiosity that we love to absorb and to
• 53:37
  Speaker 1: shoot back at you. Yeah, we hope we shed some
• 53:39
  Speaker 1: light on these topics and then you come back for more.
• 53:42
  Speaker 1: Thanks for joining us, see you next time. Thanks for listening,
• 53:53
  Speaker 1: and remember that Daniel and Jorge explained the universe is
• 53:56
  Speaker 1: a production of I heart Radio. For more podcast from
• 53:59
  Speaker 1: my heart Radio, visit the i heart Radio app, Apple Podcasts,
• 54:03
  Speaker 1: or wherever you listen to your favorite shows. H