Latest / Daniel and Kelly’s Extraordinary Universe / What is the densest thing in the universe?

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What is the densest thing in the universe? · Daniel and Kelly’s Extraordinary Universe

• 0:08
  Speaker 1: Hey, or Hey. You know how sometimes everybody thinks they
• 0:11
  Speaker 1: know the answer to a question, but they're actually all wrong.
• 0:14
  Speaker 1: You mean, like how you think everything weird in space
• 0:17
  Speaker 1: is because of aliens. Well, that's not a good example.
• 0:20
  Speaker 1: I think it probably is because of aliens. Or you mean, like,
• 0:23
  Speaker 1: what why people think this guy is blue? Yeah, a
• 0:25
  Speaker 1: lot of people think this guy is blue because of
• 0:27
  Speaker 1: the ocean. Wait, it's not because of the ocean. Do
• 0:30
  Speaker 1: you even listen to our podcast? We did a whole
• 0:32
  Speaker 1: episode about that. I don't listen to our podcast. I'm
• 0:34
  Speaker 1: too busy looking out for aliens. Well, if you did
• 0:37
  Speaker 1: pay attention, sometimes you'd realize that sometimes there's a question
• 0:40
  Speaker 1: in science that everybody assumes they know the answer to,
• 0:43
  Speaker 1: but it turns out they don't. Hi. I'm or Hey.
• 1:02
  Speaker 1: I'm a cartoonists and the creator of PhD comics. Hi
• 1:06
  Speaker 1: I'm Daniel. I'm a podcast host and part time particle physicist.
• 1:10
  Speaker 1: Have you been downgraded to part time? Now? I decided
• 1:13
  Speaker 1: let's make this podcast thing my primary activity. That's right,
• 1:16
  Speaker 1: it's two hours a week, but it's the most important
• 1:18
  Speaker 1: and valuable two hours of my week. Two hours of work.
• 1:21
  Speaker 1: Isn't that too much? For a physicist. Well, you know,
• 1:25
  Speaker 1: you've got your naps in, you've got your coffee breaks,
• 1:28
  Speaker 1: you got your scribbling nonsense on the board to look busy.
• 1:31
  Speaker 1: So it's a pretty full day after a while, you
• 1:33
  Speaker 1: mean a pretty full week, pretty for a week. Yeah,
• 1:36
  Speaker 1: you know. But I modeled my work day after my
• 1:38
  Speaker 1: um my cartooning role models. You know. Yeah, sleep in,
• 1:43
  Speaker 1: never change out of your pajamas, this kind of stuff. Yeah, No,
• 1:46
  Speaker 1: we should all look up to cartoonists as a nation.
• 1:50
  Speaker 1: We would all be more productive if we follow the
• 1:52
  Speaker 1: cartooning work week. We'd all be a lot more funny,
• 1:56
  Speaker 1: that's right. We would do the low way to prosperity.
• 1:58
  Speaker 1: But you are listeners are listening to our podcast, Daniel
• 2:02
  Speaker 1: and Jorge Explain the Universe, a production of I Heart Radio,
• 2:06
  Speaker 1: in which we take weird and funny and amazing and
• 2:08
  Speaker 1: crazy things about the universe and try to doodle them
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  Speaker 1: into your brain with silly analogies and bad jokes. That's right.
• 2:15
  Speaker 1: We try to take you to the corners, the far
• 2:17
  Speaker 1: reaching corners of the universe, and to explore the heaviest things,
• 2:22
  Speaker 1: the biggest things, the brightest things, the smallest things that
• 2:26
  Speaker 1: are out there for us to discover that's right, And
• 2:29
  Speaker 1: so we have this series of podcasts we've been really
• 2:31
  Speaker 1: enjoying about the extreme Universe, Extreme Extreme, in which we
• 2:37
  Speaker 1: look at all the weirdest, nastiest, hottest, wettest, craziest things
• 2:41
  Speaker 1: in the universe, and we have actually done some of those.
• 2:43
  Speaker 1: We did the hottest, we did the brightest, we did
• 2:45
  Speaker 1: the biggest. What else did we do? You Ma, you
• 2:47
  Speaker 1: make our podcast sound a little not safe for work there, Daniel.
• 2:51
  Speaker 1: That's all in the minds of the listener. Okay, well,
• 2:53
  Speaker 1: that's that's kind of the universe totally. The universe is
• 2:56
  Speaker 1: not safe for work. Oh I thought you meant the
• 3:00
  Speaker 1: universe is in the minds of the listener, which is
• 3:02
  Speaker 1: also sort of true from a philosophical point of view.
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  Speaker 1: So today we're continuing our series of extreme Things in
• 3:07
  Speaker 1: the universe, and in this episode we are going to
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  Speaker 1: explore what is the dnsest thing in the universe, the
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  Speaker 1: densest thing in the universe, that's right, Not the heaviest,
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  Speaker 1: not the biggest, not the smallest, but the most compact,
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  Speaker 1: the thing with the most stuffed stuffed into it, that's right,
• 3:29
  Speaker 1: Not the sharpest thing, the densest thing, that's right, Not
• 3:33
  Speaker 1: the brightest thing, but the densest things, right, Not the
• 3:38
  Speaker 1: smartest thing in the universe, the dances, that's right. Yeah,
• 3:41
  Speaker 1: the smartest thing in the universe. That would be an
• 3:42
  Speaker 1: interesting discussion. I wonder what is the smartest thing in
• 3:45
  Speaker 1: the universe. Do you think it's a human? Who? You
• 3:46
  Speaker 1: think it's some super intelligent alien race? I think the
• 3:49
  Speaker 1: universe is the smartest thing in the universe. Oh snap,
• 3:52
  Speaker 1: we are the universe thinking? Is that what you're thinking?
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  Speaker 1: Where you're going? We are the brain of the universe.
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  Speaker 1: The universe is us. It's very holistic of you. I
• 4:00
  Speaker 1: gotta get some of those banana peals you must have
• 4:02
  Speaker 1: been smoking for today's episode. I am one with the universe,
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  Speaker 1: and the universe is me, and I am thinking the
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  Speaker 1: thoughts of the universe. Well, I but I don't. I
• 4:09
  Speaker 1: don't smoke banana peals. I just I just eat them. Wrong,
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  Speaker 1: You eat them, you eat the flesh, and I smoked
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  Speaker 1: the peels. So we're a perfect team. Well, so, yeah,
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  Speaker 1: what is the densest thing you meaning? Like, what is
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  Speaker 1: the most compact crunched up think? Is you know, craziest
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  Speaker 1: most amount of stuff in a small amount of space.
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  Speaker 1: Thing that exists out there in the universe, that's right.
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  Speaker 1: And the point of this series, the Extreme Universe series,
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  Speaker 1: is to remind you that our little corner of the
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  Speaker 1: universe is fairly ho hum. It's not very fast, it's
• 4:40
  Speaker 1: not very big, it's not very hot, it's not very cold.
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  Speaker 1: It's sort of just right. And what that means is
• 4:45
  Speaker 1: that there is crazy stuff out there, this stuff out
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  Speaker 1: there that's bigger you than you can imagine, that's hotter
• 4:50
  Speaker 1: than you can imagine, that's emptier than you can imagine.
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  Speaker 1: And one of my funniest extremes is density. To imagine
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  Speaker 1: how much stuff you can cram into the tiniest spot,
• 5:00
  Speaker 1: get those atoms all crowded up into each other. Because
• 5:03
  Speaker 1: when that happens, really weird things happen. Matter does all
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  Speaker 1: sorts of strange stuff when you squeeze it together. And
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  Speaker 1: so a lot of our listeners, a lot of you
• 5:10
  Speaker 1: listening out there, might be thinking, Oh, I know the
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  Speaker 1: answer to this question. It's obviously a black hole. Hint,
• 5:17
  Speaker 1: it's not a black hole. It's not a black hole.
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  Speaker 1: Maybe it is, maybe it isn't. There's a bit of
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  Speaker 1: a philosophical argument there at the end teaser, there's a
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  Speaker 1: plot twist. It is it isn't It is it isn't.
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  Speaker 1: Some people say it is, some people say it isn't.
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  Speaker 1: Those other people throw the other first people into a
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  Speaker 1: black hole, and the argument and at all just becomes
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  Speaker 1: a black hole of a mess exactly, it becomes a
• 5:42
  Speaker 1: mental black hole. We all get a little denser. So
• 5:45
  Speaker 1: hopefully that sucked you in into the topic of this podcast,
• 5:49
  Speaker 1: and so stay tuned to see if it is or
• 5:51
  Speaker 1: if it's not a black hole. Daniel says, maybe it
• 5:53
  Speaker 1: is not, Maybe it is, maybe it's not. Exactly, But
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  Speaker 1: before we dive into that, I went around and I
• 5:59
  Speaker 1: asked folks on campus that you see Irvine. I said,
• 6:01
  Speaker 1: what do you think is the densest thing in the universe?
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  Speaker 1: Because I was curious, is everybody just going to say
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  Speaker 1: it's a black hole? To people have other ideas? Have
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  Speaker 1: people done the careful reading about the fundamental issues in
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  Speaker 1: the corners and the centers black holes? Or maybe people
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  Speaker 1: knew what the densest thing in the universe is. Maybe
• 6:17
  Speaker 1: there it's it's something else and people knew about it. Yeah,
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  Speaker 1: that's right. Maybe it's the center of some weird kind
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  Speaker 1: of candy and you know, famously dance or something else
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  Speaker 1: weird people have read about. So I walked around I
• 6:28
  Speaker 1: asked people. I said, what do you think is the
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  Speaker 1: densest thing in the universe? So think about it for
• 6:33
  Speaker 1: a second, and if somebody asked you on the street,
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  Speaker 1: what is the denist thing in the universe, would you
• 6:37
  Speaker 1: answer that it's a black hole. Here's what people had
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  Speaker 1: to say. A black hole. Oh, man, I hope it's
• 6:43
  Speaker 1: chocolate black hole. Probably a black hole, a black hole,
• 6:48
  Speaker 1: neutron stars, something like that. Black holes gets the anti
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  Speaker 1: matter black hole. I think I want to say the core,
• 6:56
  Speaker 1: the core core of the Earth, okay, okay, or actually,
• 7:00
  Speaker 1: so you know universe, probably the sun in the star, right, yeah,
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  Speaker 1: I would say a star al right. So most people
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  Speaker 1: answered black hole. A lot of people said it's a
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  Speaker 1: black hole. It's a good go to thing. I think
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  Speaker 1: people think what's the densest thing in the universe and
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  Speaker 1: their mind goes straight to a black hole because they
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  Speaker 1: imagine a black hole has a lot of stuff stuffed
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  Speaker 1: into it. But it wasn't the only answer. There was
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  Speaker 1: some pretty interesting ones here. I like the one that
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  Speaker 1: said it's chocolate exactly. I'm not sure that was a
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  Speaker 1: serious answer. Somebody out there really had a hanker and
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  Speaker 1: for some dark, dark chocolate. Right. The thing that interested
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  Speaker 1: me about these answers maybe they were thinking like richest,
• 7:35
  Speaker 1: Like what's the richest thing you've ever tasted? Most? What's
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  Speaker 1: the most calorie dense thing in the universe? Maybe that's
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  Speaker 1: what they're thinking. There you go, is it still a
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  Speaker 1: black hole? Like what if you eat a black hole?
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  Speaker 1: That's a lot of calories technically, right, what if you
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  Speaker 1: ate a black hole? I think that's a physics question
• 7:52
  Speaker 1: nobody has ever asked me before. While we are breaking
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  Speaker 1: new ground today. One of the things I liked about
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  Speaker 1: these answers is in contrast to someone the other extreme
• 8:01
  Speaker 1: universe questions, where you you might have noticed people tended
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  Speaker 1: to answer in their local environment. They're like, thought about
• 8:06
  Speaker 1: what is the brightest thing in our solar system? Or
• 8:08
  Speaker 1: what is the biggest thing nearby here? People really went
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  Speaker 1: s at a universal They really cast their minds into
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  Speaker 1: the entire universe to find something really really dense. I
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  Speaker 1: mean like the person who said it was the core
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  Speaker 1: of the earth exactly, not that person, everybody, but that
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  Speaker 1: person yeah, all right, Well there were other answers here.
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  Speaker 1: Some people said neutron stars, other people said antimatter. Those
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  Speaker 1: are pretty a space physics the answers yeah, yeah, I
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  Speaker 1: think antimatters a would have stabbed there. You know, Um,
• 8:37
  Speaker 1: antimatter is not anymore or less than the normal matter, right,
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  Speaker 1: it's just another kind of matter. It's at the opposite
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  Speaker 1: kind of matter. But a neutron star is a good answer. Um.
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  Speaker 1: I like the people who said, you know, I don't
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  Speaker 1: know something strange out there in space like that, you know,
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  Speaker 1: just conveys the whole idea we're trying to get across here,
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  Speaker 1: which is that space is filled with weird stuff, something
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  Speaker 1: crazy and strange and you probably can't even imagine. Well,
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  Speaker 1: that needs to be the answer to every single one
• 9:04
  Speaker 1: of these extreme universe episodes. It's like, what's the brightest
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  Speaker 1: thing in the universe, some weird thing out there in space,
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  Speaker 1: something in space. I've noticed this trend that you seem
• 9:15
  Speaker 1: to be trying to assemble a sort of universal list
• 9:18
  Speaker 1: of answers to physics questions, Like how many physics questions
• 9:21
  Speaker 1: can you just answer with the with the phrase the
• 9:23
  Speaker 1: Big bang or space or you know, physics. Um, it's
• 9:27
  Speaker 1: like you're trying to find shortcuts or something. Well, you know,
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  Speaker 1: I want to be ready when that physicist approaches me
• 9:31
  Speaker 1: on the street wearing sandals and asking me strange questions
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  Speaker 1: about the universe. I want to be ready. You know,
• 9:39
  Speaker 1: you want to be ready. I think we should do
• 9:41
  Speaker 1: that someday. We should just flip your answers in and
• 9:43
  Speaker 1: see if any listeners even noticed. Right, do I get
• 9:45
  Speaker 1: to Google first? Nobody gets to Google first. There's no
• 9:49
  Speaker 1: googling allowed in these questions. It's just what do you know? Now?
• 9:52
  Speaker 1: What's in your mind? What answer can you construct? All right, well,
• 9:55
  Speaker 1: let's launch into this discussion, Daniel. Let's figure out what
• 9:58
  Speaker 1: is the dancest thing in the universe. But first let's
• 10:01
  Speaker 1: maybe talk about what is density. I think we all
• 10:04
  Speaker 1: have an intuitive sense of what density is, but you know,
• 10:07
  Speaker 1: maybe there's a it's different from the physics definition. Yeah,
• 10:10
  Speaker 1: and we talk a lot in this podcast about sort
• 10:12
  Speaker 1: of the difference between technical physical definitions and sort of
• 10:15
  Speaker 1: cultural definitions, and in this one case, I think they're
• 10:19
  Speaker 1: pretty well aligned. But let's just go through the basics.
• 10:22
  Speaker 1: Being people up to speed in case they haven't thought
• 10:23
  Speaker 1: about density. Since you know high school chemistry or something
• 10:27
  Speaker 1: um And so density is not a fundamental unit, it's
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  Speaker 1: a derived unit, which means it's a ratio of two
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  Speaker 1: other things. It's mass over volume. So mass is just
• 10:35
  Speaker 1: like how much stuff is there. It's different from weight. Right, Wait,
• 10:38
  Speaker 1: is how much force is there on you from from
• 10:41
  Speaker 1: Earth's gravity. Mass is just like how much stuff is
• 10:44
  Speaker 1: there in you? Right, And remember we talked about that
• 10:46
  Speaker 1: another time. What is mass? And it comes from inertia
• 10:49
  Speaker 1: and it's the property of an object to resist changes
• 10:52
  Speaker 1: in its motion. Right, So that's what mass is. All
• 10:54
  Speaker 1: the particles inside you and all their energy addupt to
• 10:56
  Speaker 1: give you a certain amount of mass. And then on
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  Speaker 1: the bottom of that volume, right, So it's mass over
• 11:01
  Speaker 1: a volume. And volume is just how much space do
• 11:04
  Speaker 1: you take up? Right? How big are you? So something
• 11:07
  Speaker 1: can be really dense if it has a lot of
• 11:08
  Speaker 1: mass and not very much volume, or not very much
• 11:11
  Speaker 1: mass but even less volume. Right. So it's not about
• 11:14
  Speaker 1: being extremes in mass or extremes in volume. It's all
• 11:17
  Speaker 1: about the ratio. It's having a lot of mass in
• 11:20
  Speaker 1: a small space. I see. It's not about being the
• 11:22
  Speaker 1: biggest thing or about having the most mass. It's about
• 11:25
  Speaker 1: having the most mass in the smallest amount of space. Yeah,
• 11:29
  Speaker 1: because you can think of things that are really really
• 11:31
  Speaker 1: big and really really massive, but not very dense, like
• 11:35
  Speaker 1: a blimp. Right. You know, a blimp is not that
• 11:37
  Speaker 1: dense because it can float in the air. Right, It's
• 11:39
  Speaker 1: filled with a gas that's less dense than air, even
• 11:42
  Speaker 1: though it's really big and uh and and it has
• 11:45
  Speaker 1: a huge amount of mass to it. A blimp is
• 11:47
  Speaker 1: not actually that dense. But if the blimp was made
• 11:49
  Speaker 1: out of rocks, that would be really really dense. That's right.
• 11:53
  Speaker 1: That would be a terrible design for a blimp exactly. Um,
• 11:57
  Speaker 1: I don't recommend you buy any stocks and your friends
• 12:00
  Speaker 1: rock blimp startup. Well, it depends on what you're trying
• 12:03
  Speaker 1: to float in, right, If you're trying to float into
• 12:05
  Speaker 1: something that is denser than rock, then they would work. Yeah,
• 12:09
  Speaker 1: that's true. I'm not sure where that exists, so you know,
• 12:12
  Speaker 1: he's lava denser than rock, probably not right, So I'm
• 12:15
  Speaker 1: not sure where your rock blimp would even work, but
• 12:18
  Speaker 1: sure yeah, maybe you know, on the surface sid maybe
• 12:21
  Speaker 1: in the liquid nitrogen oceans of Jupiter. There you go, there,
• 12:26
  Speaker 1: there you go. There's a great reason to invest in
• 12:29
  Speaker 1: your in that startup now. Yeah. But the point is,
• 12:32
  Speaker 1: things can be really big and really massive without being
• 12:35
  Speaker 1: very dense. Right. Dense requires a huge amount of mass
• 12:37
  Speaker 1: compacted into a small space. So the densest thing in
• 12:40
  Speaker 1: the universe doesn't have to be something big. It can
• 12:43
  Speaker 1: be something small, that's right. And things can be very
• 12:45
  Speaker 1: very dense without being that big. Right. You can have
• 12:48
  Speaker 1: a really really small amount of something that's very dense
• 12:51
  Speaker 1: as long as there's a huge amount of stuff crammed
• 12:54
  Speaker 1: into it. But it could also be a really big thing,
• 12:56
  Speaker 1: like you could you know, the densest thing in the
• 12:59
  Speaker 1: universe could be like a star or a neutron star.
• 13:01
  Speaker 1: It could be something that big. Yeah, exactly, it could
• 13:03
  Speaker 1: be big, it could be small. It could be massive,
• 13:05
  Speaker 1: it could be not that massive. The key is the
• 13:07
  Speaker 1: ratio again between the mass and the volume, how much
• 13:10
  Speaker 1: stuff is cramped into a certain amount of space exactly.
• 13:14
  Speaker 1: And you know, that's physics density, And I think that
• 13:16
  Speaker 1: matches pretty well with what people's intuition is for density.
• 13:19
  Speaker 1: I don't think we have a pretty big disconnect like
• 13:22
  Speaker 1: we usually do. So congratulation Physics Naming team. You picked
• 13:26
  Speaker 1: a good one this time. Well, I guess intuitively, you know,
• 13:29
  Speaker 1: it's kind of like, um, holding something in your hand.
• 13:32
  Speaker 1: You know, like if you're holding a little rock that's
• 13:34
  Speaker 1: dense and you know it's dnse because it feels heavy,
• 13:37
  Speaker 1: but it still fits in your hand. But if you
• 13:39
  Speaker 1: have you have like a ball of cotton in your hand,
• 13:42
  Speaker 1: that's not very dense, that's right. And so one way
• 13:44
  Speaker 1: to compare densities is to say, I'm going to compare
• 13:48
  Speaker 1: different kinds of stuff and have the same volume, so
• 13:50
  Speaker 1: the same amount of its same like physical space full
• 13:53
  Speaker 1: of it, and then just compare the mass because it's
• 13:56
  Speaker 1: the ratio of mass to volume. And if you fix
• 13:58
  Speaker 1: the volume, then you can just compare the mass us.
• 14:00
  Speaker 1: So you can compare like a handful of rock to
• 14:03
  Speaker 1: a handful of cotton, to a handful of air to
• 14:06
  Speaker 1: a handful of you know, hot lava or whatever. And
• 14:09
  Speaker 1: don't actually try to get a handful of hot lava,
• 14:11
  Speaker 1: but hand full of lava sounds like it sounds like
• 14:15
  Speaker 1: a you know, a high school band name or something
• 14:17
  Speaker 1: up next an extreme universe handful of lava. Anyway, Um, yeah,
• 14:23
  Speaker 1: you if you fix the volume, then you can compare
• 14:26
  Speaker 1: the mass. Okay, so you have a couple of great
• 14:28
  Speaker 1: interesting numbers here for us, and they're all based on
• 14:31
  Speaker 1: a fixed volume, which is a one teaspoon, right, that's right.
• 14:34
  Speaker 1: I thought a teaspoon is like a macroscopic quantity. You know,
• 14:37
  Speaker 1: you can imagine it's just like a normal kitchen spoonful
• 14:40
  Speaker 1: of stuff. And then we can think about how heavy,
• 14:43
  Speaker 1: how much mass is there in a teaspoon of this
• 14:46
  Speaker 1: versus a teaspoon of that versus the teaspoon of something else.
• 14:48
  Speaker 1: So if we fix the volume, then we can just
• 14:50
  Speaker 1: think about how much mass there is, how much a
• 14:52
  Speaker 1: teaspoon of something would Wait, that's right now. Wait, of
• 14:56
  Speaker 1: course is slightly different from mass, but you know they're connected.
• 14:59
  Speaker 1: And here Earth, something that has more mass has more weight. Um,
• 15:03
  Speaker 1: you know, far away from the Earth, then you can
• 15:05
  Speaker 1: still have mass even if you don't have weight. But
• 15:07
  Speaker 1: they're the same if we're if we're doing this experiment
• 15:09
  Speaker 1: on the surface of the Earth, then it's equivalent. So
• 15:11
  Speaker 1: step us through here, Daniel. All right, so I thought
• 15:13
  Speaker 1: we'd start really really light, all right, just sort of
• 15:16
  Speaker 1: for scale, and imagine if you had, for example, um,
• 15:20
  Speaker 1: a teaspoon of space right. I mean, I don't know
• 15:22
  Speaker 1: how you would get that, but so you like scooped
• 15:24
  Speaker 1: up a teaspoon of space, so you had, you know,
• 15:27
  Speaker 1: stuff that had the same density of space. Like what
• 15:29
  Speaker 1: do you mean space, like average space or like if
• 15:32
  Speaker 1: you win out into space, grabbed the scoop of it
• 15:35
  Speaker 1: and brought it back to Earth. Is that what you mean? Yeah?
• 15:38
  Speaker 1: The average amount the average amount of stuff in space.
• 15:41
  Speaker 1: And remember we did a whole podcast episode about how
• 15:43
  Speaker 1: space he is space and it turns out that the
• 15:45
  Speaker 1: answer is pretty different depending on where you get your
• 15:48
  Speaker 1: scoop of space. But in all cases, as long as
• 15:51
  Speaker 1: you're far away from the Earth's atmosphere, the answer is
• 15:53
  Speaker 1: pretty pretty low. You know, you're gonna get less than
• 15:56
  Speaker 1: one proton in your tea spoon. Okay, so this is
• 15:59
  Speaker 1: like the average teaspoon of the universe. Yeah, exactly. The
• 16:03
  Speaker 1: average density of a teaspoon in the universe is one
• 16:06
  Speaker 1: times ten to the negative twenty seven kilograms, So that's
• 16:11
  Speaker 1: zero point twenties seven. Zero's one. That's how much a proton. Ways,
• 16:17
  Speaker 1: so you can have like a whole teaspoon with just
• 16:18
  Speaker 1: a proton in it. That's about the average density of
• 16:21
  Speaker 1: stuff out there, and a proton is pretty small, right,
• 16:25
  Speaker 1: I mean it's it's pretty much. Uh, it's it's tiny.
• 16:30
  Speaker 1: It's almost nothing, right, it's almost a fundamental unit of
• 16:33
  Speaker 1: of mass. Right. Yeah, it's amazing because it's almost nothing.
• 16:36
  Speaker 1: But then it makes up everything, right, And it's incredible
• 16:38
  Speaker 1: how you can get big macroscopic stuff made out of
• 16:42
  Speaker 1: super tiny stuff. Right. It boggles the mind how small
• 16:45
  Speaker 1: a proton is, and then how many protons you need
• 16:47
  Speaker 1: to make, Like you know, a cookie or whatever. There's
• 16:50
  Speaker 1: so many protons in your cookie and you don't even
• 16:52
  Speaker 1: think about them as you eat it. Wow. So that's
• 16:53
  Speaker 1: the average density of the universe really, right, it's it's
• 16:57
  Speaker 1: about one proton per teaspoon. And the reason is, you know,
• 17:01
  Speaker 1: there's a lot of stuff out there in the universe,
• 17:03
  Speaker 1: a lot of stars and they're big, and a lot
• 17:05
  Speaker 1: of galaxies, but most of the universe is pretty empty,
• 17:08
  Speaker 1: you know, the stuff between stars and between galaxies. There's
• 17:10
  Speaker 1: not that much stuff there. And the biggest volume of
• 17:13
  Speaker 1: the universe are these super voids, you know, between the
• 17:16
  Speaker 1: sheets of superclusters. But there's really basically almost nothing. And
• 17:20
  Speaker 1: so because density is mass over volume, and the volume
• 17:23
  Speaker 1: of the universe is unbelievably gigantic. Then that's why the
• 17:27
  Speaker 1: density is so small. I mean, it's amazing that it's
• 17:29
  Speaker 1: even anywhere close to a proton. Frankly, Wow, that's pretty
• 17:33
  Speaker 1: incredible to think that if you sort of, like if
• 17:35
  Speaker 1: you shrank the entire universe into a teaspoon, like everything
• 17:39
  Speaker 1: that's stuff, stars as planets, would just be about the
• 17:43
  Speaker 1: size of a proton exactly. But but the next I thought,
• 17:45
  Speaker 1: let's let's look at something sort of around here on
• 17:48
  Speaker 1: the Earth, and and a good sort of normalization for
• 17:51
  Speaker 1: like a standard for what density is is water, because
• 17:54
  Speaker 1: water is one um gram per cubic centimeter, right, and
• 18:00
  Speaker 1: a teaspoon is five cubic centimeters, So water is five
• 18:03
  Speaker 1: grams per cubic centimeter. So you have a teaspoon of water,
• 18:06
  Speaker 1: it weighs five grams, which is a whole lot more
• 18:09
  Speaker 1: than a proton. What about a teaspoon of tea? A
• 18:13
  Speaker 1: teaspoon of tea, that's a good question. It must be
• 18:16
  Speaker 1: a little bit more dense, right because you put something
• 18:19
  Speaker 1: into it, but it's about the same, Okay, So that's um.
• 18:26
  Speaker 1: I think that's a pretty good anchor for people, maybe,
• 18:28
  Speaker 1: you know, because we're all sort of familiar with how
• 18:31
  Speaker 1: water feels and how much it wasgs. That's right, And
• 18:34
  Speaker 1: if you're holding a teaspoon, you can tell the difference
• 18:36
  Speaker 1: between having a full teaspoon and an empty teaspoon. Right,
• 18:39
  Speaker 1: somebody pours water into your teaspoon with your eyes closed,
• 18:41
  Speaker 1: you can tell the difference. Whereas if I put a
• 18:43
  Speaker 1: single proton in your teaspoon, you're not gonna notice. So
• 18:46
  Speaker 1: you can feel it, right, you can feel five grams.
• 18:49
  Speaker 1: It's not it's not a lot, but it's also not nothing.
• 18:51
  Speaker 1: That really kind of tells you how empty the universe is, right, Like,
• 18:54
  Speaker 1: if our average experience of matter is a teaspoon of water,
• 19:00
  Speaker 1: compare that to a teaspoon with one proton in it.
• 19:02
  Speaker 1: That's that's really kind of the difference between our everyday
• 19:05
  Speaker 1: experience and the actual whole other rest of the universe,
• 19:09
  Speaker 1: exactly at the low extreme, most of the universe is
• 19:12
  Speaker 1: really not very dense at all, So we live in
• 19:14
  Speaker 1: a pretty dense place compared to most of the universe.
• 19:17
  Speaker 1: But then again, as you'll hear, our surroundings are not
• 19:20
  Speaker 1: very dense at all compared to the densest places in
• 19:22
  Speaker 1: the universe, So The craziest thing about the universe is
• 19:25
  Speaker 1: that it has this enormous range. Most of it's not
• 19:28
  Speaker 1: very dense at all, and then there's these incredible pockets
• 19:31
  Speaker 1: of total density. Well, let's keep scooping up more and
• 19:34
  Speaker 1: more dens for things. But first let's take a quick break.
• 19:51
  Speaker 1: All right, we're scooping things up indiscriminately here and measuring
• 19:54
  Speaker 1: their density to find out the densest thing in the universe.
• 19:58
  Speaker 1: And we we just scipped up some water. So some
• 20:00
  Speaker 1: water is about five grams that's right, five grams per
• 20:03
  Speaker 1: tea spoon. And then people, um, a lot of people said, oh,
• 20:06
  Speaker 1: maybe the sun or a star. That seems like a
• 20:08
  Speaker 1: dense thing, right, because it seems like it's trapped by
• 20:11
  Speaker 1: gravity and the reason it's burning is that it's all
• 20:14
  Speaker 1: this gasp and compressed. So people figure, well, it must
• 20:17
  Speaker 1: be pretty dense, right, Well, it is dense, but it's
• 20:20
  Speaker 1: surprisingly not that dense. I mean, the density of the
• 20:22
  Speaker 1: sun is about seven grams per teaspoon, so only a
• 20:26
  Speaker 1: little bit denser than water. Are you serious? Yeah, the
• 20:29
  Speaker 1: sun is not that much denser than water. Yeah, the
• 20:33
  Speaker 1: Sun is not that much denser than the water. Now,
• 20:35
  Speaker 1: the sun is really big, and the Sun is really hot,
• 20:38
  Speaker 1: but it's not actually that dense. So this is the
• 20:41
  Speaker 1: average density of the Sun, because I imagine the Sun
• 20:44
  Speaker 1: is dens or at the middle in the middle unless
• 20:46
  Speaker 1: dense at the edges. Right, the Sun really doesn't like
• 20:49
  Speaker 1: when you talk about its middle that way. It's been
• 20:51
  Speaker 1: working on it for a few billion years um. But yes,
• 20:54
  Speaker 1: the the density of the Sun does vary. So this
• 20:56
  Speaker 1: is the average density exactly. And I think the reason
• 21:00
  Speaker 1: that it's not more dense is that there's more than
• 21:03
  Speaker 1: just gravity going on. Right. Gravity is the thing that
• 21:05
  Speaker 1: made the Sun. It pulled all that stuff together, it
• 21:08
  Speaker 1: starts that fire. But once you have that fire happening,
• 21:11
  Speaker 1: it's like a constant explosion, and that explosion is making
• 21:15
  Speaker 1: the Sun less dense. So the Sun is this constant balance, right,
• 21:18
  Speaker 1: It's a trapped, ongoing nuclear explosion. The explosions are pushing
• 21:22
  Speaker 1: things out and gravity is pulling things in. And so
• 21:25
  Speaker 1: if it was just gravity, then you know, the Sun
• 21:27
  Speaker 1: would collapse into a very very dense state. But the
• 21:30
  Speaker 1: reason it doesn't collapse is because it's exploding, so that
• 21:33
  Speaker 1: keeps it, you know, a little fluffy, So you're really
• 21:35
  Speaker 1: only kind of measuring the density of the fuel of
• 21:38
  Speaker 1: the sun, Like once it turns into fire and photons
• 21:42
  Speaker 1: once it turns into light, you don't really count that
• 21:44
  Speaker 1: as part of the density. That's right, we're measuring the
• 21:47
  Speaker 1: matter density of the sun. But you know a lot
• 21:49
  Speaker 1: of the photons produced in the sun never leave it
• 21:51
  Speaker 1: because they're reabsorbed. You make a photon somewhere in the
• 21:54
  Speaker 1: middle of the sun, it's going to get reabsorbed before
• 21:56
  Speaker 1: it leaves the sun. But I think they did is
• 21:58
  Speaker 1: that if you scooped up a teaspoon of the sun,
• 22:01
  Speaker 1: it would it would sort of feel the same as
• 22:03
  Speaker 1: this teaspoon of water. It might be a lot brighter, right,
• 22:07
  Speaker 1: and hotter, but exactly. Yeah, that's the idea, right, Somebody
• 22:12
  Speaker 1: out there is imagining being blindfolded, and you're saying, I'm
• 22:15
  Speaker 1: either going to pour a teaspoon of water into your
• 22:17
  Speaker 1: teaspoon or a teaspoon of the sun, and you won't
• 22:19
  Speaker 1: be able to tell which. And you're thinking, yeah, I
• 22:22
  Speaker 1: think I'll be able to tell. But you're right, you
• 22:24
  Speaker 1: won't be able to tell from the from the heaviness
• 22:27
  Speaker 1: of it, because it's not that much heavier than water,
• 22:29
  Speaker 1: all right, And in fact, it seems like things are
• 22:31
  Speaker 1: even denser here on Earth. Yeah, exactly. And you might
• 22:33
  Speaker 1: be thinking, well, water is not that dense, and you're right,
• 22:36
  Speaker 1: And if you just like bent down and scooped up
• 22:38
  Speaker 1: a teaspoon of rocks, you know of like gravel or whatever,
• 22:42
  Speaker 1: then you would have something denser. In fact, the density
• 22:44
  Speaker 1: of the Earth, again averaging over everything in the Earth,
• 22:47
  Speaker 1: is thirty grams per teaspoon. Remember waters five grams, the
• 22:52
  Speaker 1: sun is seven grams. The Earth is thirty grams per teaspoon.
• 22:56
  Speaker 1: That's a lot denser than the Sun. So the Sun
• 22:58
  Speaker 1: is actually kind of fluffy, right, Yeah, it's like a
• 23:01
  Speaker 1: big cozy pillow on fire. Yeah. And the reason is right,
• 23:04
  Speaker 1: the Earth is not on fire. Right. If the Earth
• 23:09
  Speaker 1: was more massive so that there was more gravity so
• 23:12
  Speaker 1: we can press it more infusion would get started, then
• 23:14
  Speaker 1: it would actually get bigger, right, and then it would
• 23:17
  Speaker 1: be more fluffy. So Earth is more dense because we
• 23:19
  Speaker 1: only have gravity going on. We have no outward pressure
• 23:22
  Speaker 1: from fusion to make us fluffy. We're not living in
• 23:25
  Speaker 1: an explosion. We are pretty compact. So but that's kind
• 23:29
  Speaker 1: of the average density of the Earth. But there must
• 23:33
  Speaker 1: be things on Earth that are denser than the average density.
• 23:36
  Speaker 1: Big variation in density. You know, the core of the
• 23:38
  Speaker 1: Earth is more dense than the rocks under your feet,
• 23:41
  Speaker 1: for example. So there's a lot of variation. But if
• 23:44
  Speaker 1: you look around on Earth, for like, what is the
• 23:46
  Speaker 1: densest thing that occurs on Earth? There's this one element
• 23:49
  Speaker 1: it's called osmy um, and osmium weighs a hundred ten
• 23:53
  Speaker 1: grams per teaspoon a hundred and ten grams, so like, um,
• 23:58
  Speaker 1: that's a lot. That's like, how much is that like
• 24:01
  Speaker 1: fifteen scoops of the sun compressed down? Is how much
• 24:07
  Speaker 1: osm that's right? Um, If you had a teaspoon of osmium,
• 24:11
  Speaker 1: it would feel like you had like a half a
• 24:13
  Speaker 1: cup of water in your teaspoon. The stuff is pretty dense.
• 24:16
  Speaker 1: I've never seen ausman. I don't even know what it
• 24:18
  Speaker 1: looks like or if you can pour it, if it's
• 24:20
  Speaker 1: liquided room temperature or whatever. But it's the densest stuff
• 24:23
  Speaker 1: on Earth. But that's at the on the surface of
• 24:26
  Speaker 1: the Earth. Like maybe down in the center of the Earth,
• 24:28
  Speaker 1: things are more compact because there's more pressure. Yeah, and
• 24:31
  Speaker 1: you're right, the core of the Earth is more dense
• 24:34
  Speaker 1: than the rest of the Earth or the Earth's crust
• 24:36
  Speaker 1: for example, or the average density of the Earth, which
• 24:38
  Speaker 1: is what we mentioned earlier. But sort of surprisingly, it's
• 24:41
  Speaker 1: not that much more dense, Like it's twice as dense
• 24:44
  Speaker 1: at the core of the Earth than it is at
• 24:45
  Speaker 1: the Earth's crust, which is most of the Earth. But
• 24:48
  Speaker 1: so it's not crazy. It's not like a jillion times
• 24:51
  Speaker 1: denser or anything. I mean, twice as dance is a lot,
• 24:53
  Speaker 1: but it's not. It's not shocking. Okay, So now take
• 24:55
  Speaker 1: us out into space, Daniel, what are some of the
• 24:57
  Speaker 1: densest things out there in space? Well, so, as we
• 25:00
  Speaker 1: talked about, stars that are normally burning, are not actually
• 25:04
  Speaker 1: that dense, right, and so in our solar they're pretty fluffy.
• 25:07
  Speaker 1: In our Solar system, one of the densest things is
• 25:09
  Speaker 1: just the Earth, right, It's a pretty concentrated blob of rock.
• 25:13
  Speaker 1: So what you gotta do if you want something really
• 25:15
  Speaker 1: dense is something I think one of our listeners on
• 25:17
  Speaker 1: the street or one of our interviewees on the street
• 25:19
  Speaker 1: actually mentioned what you need is a failed star or
• 25:22
  Speaker 1: a star that has gone supernova and then collapsed, right.
• 25:26
  Speaker 1: And sometimes when a star blows its load, and it's
• 25:29
  Speaker 1: finished burning all of its fuel and it's expended all
• 25:32
  Speaker 1: of its energy, and that it no longer has that
• 25:35
  Speaker 1: radiation pressure to keep it fluffy. It collapses into a
• 25:38
  Speaker 1: neutron star. It's called a neutron star because the the
• 25:43
  Speaker 1: gravity is so intense that it forces all the protons
• 25:46
  Speaker 1: to give off an electron and become neutrons. And it's
• 25:48
  Speaker 1: just like a big ball of neutrons and they are
• 25:52
  Speaker 1: really scrunched in together, right, because there's so many of
• 25:54
  Speaker 1: them that the gravity really compresses things and makes it really,
• 25:58
  Speaker 1: really really dense. That's it. It's ridiculously dense because again
• 26:02
  Speaker 1: there's no process going on to counteract is, so all
• 26:05
  Speaker 1: you have is gravity. Is just like packing these little
• 26:07
  Speaker 1: neutrons and imagine like a huge bag of ping pong balls, right,
• 26:11
  Speaker 1: and you squeeze it so that they find like every
• 26:13
  Speaker 1: little gap of space gets squeezed out, and they all
• 26:15
  Speaker 1: find exactly the tightest way they can all fit together.
• 26:19
  Speaker 1: And the density of this thing is incredible. I mean,
• 26:21
  Speaker 1: it's even hard to understand. You know, we're talking about
• 26:23
  Speaker 1: a teaspoon. If you had a teaspoon of a neutron star,
• 26:27
  Speaker 1: it would be fifty times ten to the eleven kilograms.
• 26:32
  Speaker 1: That's a lot of eleven Yeah, exactly. I think that's
• 26:34
  Speaker 1: five thousand billion kilograms per teaspoon. And you rode here,
• 26:38
  Speaker 1: it's about seven hundred thousand Eiffel towers in a single
• 26:43
  Speaker 1: tea spoon. Yeah. I was trying to find an understandable
• 26:45
  Speaker 1: unit of of mass, like you know, what is comparable
• 26:49
  Speaker 1: in mass to a teaspoon of a neutron star. And
• 26:52
  Speaker 1: it turns out, you know, it's almost a million Eiffel
• 26:55
  Speaker 1: towers boiled down into a tea spoon. Like, I mean,
• 26:58
  Speaker 1: it's ridiculous, Like you couldn't hold up a sing the
• 27:00
  Speaker 1: Eiffel Tower. I mean, I know you've been working out
• 27:02
  Speaker 1: and you're pretty strong and everything, but an Eiffel tower
• 27:04
  Speaker 1: weighs a lot. Now I take a million Eiffel towers
• 27:07
  Speaker 1: and then condense them down into a tiny teaspoon, It's
• 27:10
  Speaker 1: hard to even imagine what that kind of matter is. Like,
• 27:13
  Speaker 1: what you know I am stronger in France is that
• 27:17
  Speaker 1: because the Earth is not round, there's a difference in
• 27:20
  Speaker 1: like the difference from the distance from the center of
• 27:22
  Speaker 1: the Earth. It's probably just the French wines out there.
• 27:26
  Speaker 1: You feel stronger in France. Exactly, But I think I
• 27:34
  Speaker 1: see what you're saying is that, like a neutron start
• 27:36
  Speaker 1: is really just a star that went out right, or
• 27:39
  Speaker 1: that collapse, Yeah, exactly, it finished burning. And so you're
• 27:41
  Speaker 1: saying that, like our son would be that dense, except
• 27:45
  Speaker 1: that since it's exploding, it kind of keeps everything fluffy.
• 27:49
  Speaker 1: But if you were to suddenly turn it off, all
• 27:51
  Speaker 1: that stuff woulds crunched down into something like a neutron star. Right.
• 27:55
  Speaker 1: And so to take the bomb analogy, you know, a
• 27:57
  Speaker 1: nuclear bomb when it's exploded is not actually that dense.
• 28:01
  Speaker 1: It's a huge fireball, right, But the fireball itself is
• 28:03
  Speaker 1: not that dense. It's much more dense before it explodes, right,
• 28:06
  Speaker 1: when it has all that fuel compacted into a small place.
• 28:10
  Speaker 1: After it explodes, it's much less dense. So an exploding
• 28:13
  Speaker 1: bomb is less dense than a non exploding bomb. Right.
• 28:15
  Speaker 1: It's kind of like can candy. You know how can
• 28:18
  Speaker 1: candy is big and fluffy, but if you like crunch
• 28:21
  Speaker 1: it down, then you just get one really dense piece
• 28:24
  Speaker 1: of candy. Yeah, you're making, uh, the sun sound really
• 28:28
  Speaker 1: comfortable and cozy. It's like big and fluffy like cotton candy.
• 28:32
  Speaker 1: You know, every pink pink? What is in the air
• 28:37
  Speaker 1: over your house that you think the sun is pink? Well,
• 28:40
  Speaker 1: you know that it depends on your If you're wearing
• 28:43
  Speaker 1: a rose color glasses, you know, I'll give it to you.
• 28:47
  Speaker 1: That's your cartoonist license, you know, that's your art um. Yeah, exactly.
• 28:51
  Speaker 1: So a neutron star is actually one of the densest
• 28:54
  Speaker 1: things in the universe. It's it's unbelievably dense. You know,
• 28:57
  Speaker 1: I think isn't even denser than Thor's hammer. You're the
• 29:00
  Speaker 1: Marvel Universe guy. I think it is. It is made
• 29:04
  Speaker 1: from the heart of a dying neutron star. So I
• 29:08
  Speaker 1: don't know if it's heavier, but it sounds like it's
• 29:12
  Speaker 1: maybe in the same order of magnitude. Well, so then
• 29:14
  Speaker 1: do the calculation. You know, if a teaspoon of neutron
• 29:17
  Speaker 1: star is a million Eiffel towers, then Thor's hammer is what,
• 29:21
  Speaker 1: I don't know, a hundred teaspoons, a thousand teaspoons. You know,
• 29:24
  Speaker 1: you're talking a billion Eiffel towers. So every time Thorpe
• 29:28
  Speaker 1: picks up that hammer, he's lifting a billion Eiffel towers.
• 29:31
  Speaker 1: It's a calming book. Wait, we're doing the physics of
• 29:36
  Speaker 1: comic books here today, folks. Um. Yeah, but you know,
• 29:39
  Speaker 1: not only do you have to be strong, but you
• 29:41
  Speaker 1: have to be worthy right to pick up Thor's hammer.
• 29:44
  Speaker 1: So so that's pretty dense. If you scoop up some
• 29:47
  Speaker 1: neutron star in a teaspoon, you would be picking up
• 29:51
  Speaker 1: a million Eiffel towers. Yeah, so make sure you do
• 29:53
  Speaker 1: your stretches before you try that, or you're gonna hurt yourself.
• 29:56
  Speaker 1: Make sure you use a strong spoon. Boon made out
• 30:00
  Speaker 1: of osmium, or a spoon made out of a billion
• 30:04
  Speaker 1: Eiffel towers, that's right, or vibranium. You sort of give
• 30:11
  Speaker 1: it away. You said a neutron star is one of
• 30:13
  Speaker 1: the densest things in the universe. But maybe so you're
• 30:16
  Speaker 1: saying it's not the densest thing. Well, it's it's a
• 30:18
  Speaker 1: little bit unclear. Depends a little bit who's camp you're in.
• 30:22
  Speaker 1: Are you an Einstein kind of person or are you
• 30:25
  Speaker 1: a shorting Your kind of person, Because depending on what
• 30:28
  Speaker 1: you think is going on inside a black hole, black
• 30:31
  Speaker 1: holes are either the densest thing in the universe or
• 30:34
  Speaker 1: not very dense at all. All right time to pick
• 30:37
  Speaker 1: sides Einstein versus short Anger. But first let's take a
• 30:41
  Speaker 1: quick break. All right, we're talking about the densest thing
• 30:57
  Speaker 1: in the universe, and we got to we are now
• 31:00
  Speaker 1: at um black holes. That's right, and we are right
• 31:04
  Speaker 1: smack in the middle of the longest standing physics grudge match.
• 31:08
  Speaker 1: It's general relativity versus quantum mechanics, Albert Einstein versus Schrodinger
• 31:14
  Speaker 1: in Heisenberg and all those other smart folks. And so
• 31:18
  Speaker 1: you might be thinking that there are Let's tell me
• 31:20
  Speaker 1: how dance is a black hole, because a black hole
• 31:22
  Speaker 1: is also something that happens after a star collapses. Right,
• 31:25
  Speaker 1: Sometimes the star performs a neutron star. Sometimes it forms
• 31:27
  Speaker 1: a black hole. And a black hole seems like it
• 31:30
  Speaker 1: must be the densest thing in the universe because it
• 31:32
  Speaker 1: has the strongest gravity. Right. The problem with the black
• 31:36
  Speaker 1: hole is that how do you define the edge of
• 31:38
  Speaker 1: the black hole? Remember that to talk about density, we
• 31:41
  Speaker 1: have to talk about mass. Black holes have huge masses,
• 31:44
  Speaker 1: but we also have to talk about volume. So what's
• 31:47
  Speaker 1: the denominator? What's the edge of the black hole? And
• 31:50
  Speaker 1: one very reasonable thing to say is that the edge
• 31:53
  Speaker 1: of the black hole is the point of no return,
• 31:55
  Speaker 1: you know, the point where if you're closer to the
• 31:58
  Speaker 1: center of the black hole than that than light can't
• 32:00
  Speaker 1: escape and nothing can never leave. Right, So you're sort
• 32:03
  Speaker 1: of saying, how do you when what do you count
• 32:06
  Speaker 1: as the black hole? Is the question exactly, because if
• 32:08
  Speaker 1: you're gonna do density, you have to calculate mass over volume.
• 32:12
  Speaker 1: So what volume are you including? So you're saying, one
• 32:14
  Speaker 1: option is to use what they call the event horizon, right, right,
• 32:19
  Speaker 1: the point where not even light can escape the vicinity
• 32:23
  Speaker 1: of the black hole. That's right, And I think that's
• 32:25
  Speaker 1: a reasonable definition because we can't see inside the event horizons.
• 32:28
  Speaker 1: We have no idea what's going on inside the event horizon,
• 32:31
  Speaker 1: so all we really can do is average over it. Right,
• 32:34
  Speaker 1: we can say, well, we know how much mass there is,
• 32:37
  Speaker 1: and we know how big it is, what's going on inside?
• 32:39
  Speaker 1: You know, that's Einstein versus Shortinger. So if you don't
• 32:42
  Speaker 1: want to be dependent on which physics genius is right
• 32:45
  Speaker 1: about the universe, then you just need to calculate the
• 32:47
  Speaker 1: mass the black hole divided by the volume includes enclosed
• 32:51
  Speaker 1: by that event horizon. So I think you're saying that
• 32:53
  Speaker 1: a black hole should be measured by when it's when
• 32:57
  Speaker 1: it's black. Yeah, exactly when the black star like that
• 33:01
  Speaker 1: where the black star and the whole holiness. That's right.
• 33:06
  Speaker 1: And the issue with black holes then is that they
• 33:09
  Speaker 1: are really really massive, right, which means it's a huge
• 33:11
  Speaker 1: amount of gravity, which means the event horizon is really
• 33:14
  Speaker 1: really big. So you say, you don't know what's going
• 33:18
  Speaker 1: on inside a black hole, but there's a huge amount
• 33:19
  Speaker 1: of mass in there. The event horizon grows linearly with mass.
• 33:23
  Speaker 1: So for example, you have twice as much mass, the
• 33:26
  Speaker 1: event horizon is twice as big. It's it's it's linear.
• 33:29
  Speaker 1: It's like a it's like a one to one increase.
• 33:33
  Speaker 1: I give you double the mass exactly. You double the
• 33:35
  Speaker 1: radius of the of the black area exactly. You double
• 33:39
  Speaker 1: the radius of the event horizon. Now, for those of
• 33:42
  Speaker 1: you you know something about geometry, think about that sphere
• 33:45
  Speaker 1: right now. If you double the radius of the sphere,
• 33:48
  Speaker 1: how much does the volume go up? Well, it goes
• 33:50
  Speaker 1: up like the radius cubed. Right. So, so you have
• 33:53
  Speaker 1: some black hole and you double its mass somehow, then
• 33:57
  Speaker 1: you've increased its mass by two, but you've increased its
• 34:01
  Speaker 1: volume by eight. Right, two cubed, so the density actually
• 34:05
  Speaker 1: goes down. So you double the mass of a black hole,
• 34:08
  Speaker 1: it's density goes down by a factor of four, which
• 34:11
  Speaker 1: means really really massive according to your definition of the
• 34:14
  Speaker 1: of the black holes, if you count the black part
• 34:17
  Speaker 1: as the black hole exactly, which seems like a reasonable
• 34:19
  Speaker 1: definition though you know, we'll talk about another definition in
• 34:22
  Speaker 1: a moment. And so what that means is that the
• 34:24
  Speaker 1: bigger your black hole is, sorry, the more massive your
• 34:27
  Speaker 1: black hole is, the less dense it actually is. But
• 34:30
  Speaker 1: you know, I guess it's a your I see what
• 34:33
  Speaker 1: you're saying, like that you should count the black as
• 34:35
  Speaker 1: the black hole. But that's it's not like a physical boundary,
• 34:40
  Speaker 1: you know, And it's not like it's not like a surface,
• 34:42
  Speaker 1: do you know what I mean. It's just where the
• 34:44
  Speaker 1: effect of the gravity starts to get crazy, but it's
• 34:48
  Speaker 1: not really sort of like you can't really touch the
• 34:50
  Speaker 1: surface of the black part, right. I wouldn't recommend it, um,
• 34:54
  Speaker 1: but you know, it is a real physical boundary. You know,
• 34:57
  Speaker 1: if you're a photon and you are pro do that
• 35:00
  Speaker 1: and you don't turn, you're gonna fall in. You know.
• 35:02
  Speaker 1: It's like saying, how big is the Grand Canyon. While
• 35:04
  Speaker 1: you start the definition at the edge of the Grand Canyon, right,
• 35:07
  Speaker 1: not at the not at the river at the bottom
• 35:09
  Speaker 1: of it. That made that Grand canyon. Right, you fall
• 35:11
  Speaker 1: in the Grand Canyon, you still fell in the Grand Canyon.
• 35:13
  Speaker 1: It doesn't matter if you fall into the edge or
• 35:15
  Speaker 1: if you jump out of a helicopter in the middle.
• 35:17
  Speaker 1: So I think it's a pretty reasonable definition that you're
• 35:20
  Speaker 1: you're putting the emphasis on the whole part. Well, that's
• 35:23
  Speaker 1: what makes the black hole so cool, right, is the
• 35:25
  Speaker 1: whole part, not the black part. So if you just
• 35:27
  Speaker 1: think of it the black hole as a whole, then
• 35:30
  Speaker 1: you have to measure where the whole starts. Yeah, so
• 35:33
  Speaker 1: you're saying them the density of the black hole, not
• 35:36
  Speaker 1: determined by how much mass is inside of the black hole,
• 35:40
  Speaker 1: is just kind of like how big the hole is,
• 35:42
  Speaker 1: which when it grows, it doesn't help the density, that's right,
• 35:45
  Speaker 1: because it's a connection there. Right. The more mass, the
• 35:47
  Speaker 1: bigger the hole, and the bigger the whole, the less dense, right,
• 35:51
  Speaker 1: So you sort of trapped there. In fact, to get
• 35:53
  Speaker 1: a really dense black hole, what you need to do
• 35:55
  Speaker 1: is is have um a smaller black hole. Right, If
• 36:00
  Speaker 1: you take half of the mass away from the black hole,
• 36:02
  Speaker 1: which of course you can't do, right, Then the mass
• 36:05
  Speaker 1: goes down by two, but the volume goes down by eight.
• 36:08
  Speaker 1: And so now the density increases by a factor of four. Okay,
• 36:12
  Speaker 1: so then the smaller the black hole, the denser it is. Yes, exactly,
• 36:16
  Speaker 1: So start with like a really big black hole, right.
• 36:19
  Speaker 1: I did some some calculations here. If you have a
• 36:21
  Speaker 1: supermassive black hole that has like the mass of four
• 36:24
  Speaker 1: billion sons, right, four billion times the mass of our Sun,
• 36:28
  Speaker 1: would be really really big black hole. It's event horizon
• 36:32
  Speaker 1: would be so big that the density of the black
• 36:34
  Speaker 1: hole would be the same as water, be five grams
• 36:38
  Speaker 1: per teaspoon of black hole. Oh, I see, because all
• 36:40
  Speaker 1: the masses just concentrated inside of this really really big hole. Exactly.
• 36:46
  Speaker 1: And again we're saying we don't know where stuff is
• 36:48
  Speaker 1: inside the hole. You know, we'll talk about that in
• 36:50
  Speaker 1: a moment. But if you have a really really dense
• 36:53
  Speaker 1: blob of matter that forms a black hole, then it's
• 36:56
  Speaker 1: event horizing is so big that it's really on average
• 36:59
  Speaker 1: on it's not denser than the water. Do you see
• 37:04
  Speaker 1: them unsatisfied by that? Well, I'm just confused a little bit.
• 37:06
  Speaker 1: So you're saying it's it's you need a billion sons
• 37:09
  Speaker 1: for this, right, four billion sons. Four billion sons. So
• 37:12
  Speaker 1: if you stuck four billion sons inside of a sphere
• 37:15
  Speaker 1: that big, it would be a black hole. It would
• 37:18
  Speaker 1: be a black hole. It doesn't matter how those sons
• 37:20
  Speaker 1: are arranged inside. It could be in a little point
• 37:23
  Speaker 1: in the middle, or it could be in a you know,
• 37:26
  Speaker 1: the form of unicorns spread all over the whole. It
• 37:28
  Speaker 1: would still create the same black hole. They could spell
• 37:31
  Speaker 1: out your name absolutely. So you're saying that we don't
• 37:34
  Speaker 1: know what the mass, how the mass is distributed inside
• 37:37
  Speaker 1: of that black sphere. It could be anything that's right,
• 37:41
  Speaker 1: and we don't because we can't see inside black holes.
• 37:43
  Speaker 1: So we don't know what the distribution of mass is.
• 37:46
  Speaker 1: Is it all in one little point in the center.
• 37:48
  Speaker 1: Is it a little fuzzier because the quantum mechanics is
• 37:51
  Speaker 1: it's some broader distribution. We don't know because we can't see.
• 37:55
  Speaker 1: That's why it's a reasonable definition to say, you know
• 37:58
  Speaker 1: everything inside this sphere, because we can't see any deeper anyway.
• 38:01
  Speaker 1: Anything beyond that requires speculation. I always thought black holes
• 38:04
  Speaker 1: had to be like a point. Everything had to be
• 38:06
  Speaker 1: inside of a little point. But you're saying that they don't.
• 38:09
  Speaker 1: They could. They could really be like like a fluffy
• 38:11
  Speaker 1: cloud of four billion sons. That's right. And another cool
• 38:14
  Speaker 1: thing is that any amount of matter can become a
• 38:16
  Speaker 1: black hole as long as you put it in the
• 38:19
  Speaker 1: right density. Right. You take your teaspoon of earth or
• 38:22
  Speaker 1: a teaspoon of water, you can make that into a
• 38:24
  Speaker 1: black hole if you candense it down to a small
• 38:26
  Speaker 1: enough area. Right, however small that event horizon has to be.
• 38:31
  Speaker 1: But if you have enough mass, right then then it
• 38:33
  Speaker 1: doesn't have to be that dense. That's the point. Right,
• 38:37
  Speaker 1: So you take four billion sons, you can distribute them
• 38:39
  Speaker 1: in a really big area and it will still be
• 38:42
  Speaker 1: a black hole, a really huge black hole. So I
• 38:45
  Speaker 1: don't recommend that if you are distributing sons around, please
• 38:47
  Speaker 1: be careful not to make a black hole. It's easier
• 38:50
  Speaker 1: than you think can be careful handling those sons. Yeah,
• 38:53
  Speaker 1: So the point is for huge masses, it's easier to
• 38:55
  Speaker 1: make a black hole because they don't have to be
• 38:57
  Speaker 1: as dense for small masses, like you want to turn
• 38:59
  Speaker 1: your teaspoon of water or tea into. A black hole
• 39:02
  Speaker 1: has to be really dense to become a black hole.
• 39:04
  Speaker 1: There is a number, right, you can calculate how small
• 39:07
  Speaker 1: you have to compress that into. But it has to
• 39:09
  Speaker 1: be really dense, all right. So then, so a super
• 39:12
  Speaker 1: massive black hole that's a four billion times the mass
• 39:15
  Speaker 1: of our Sun would actually not be that dense. It
• 39:18
  Speaker 1: would be about us dance as a tea spoon of water,
• 39:21
  Speaker 1: that's right. But if you made a black hole out
• 39:23
  Speaker 1: of just one sun, right, then it would be really
• 39:26
  Speaker 1: pretty dense. It would be about as dense as a
• 39:28
  Speaker 1: neutron star. Oh, I see, huh about us dance, But
• 39:32
  Speaker 1: but it could be denser. Well, smaller black holes in
• 39:35
  Speaker 1: that could be denser than neutron stars. Yes, but the
• 39:37
  Speaker 1: smallest black hole we've ever seen is about six times
• 39:40
  Speaker 1: the mass of the Sun. So in terms of actual
• 39:44
  Speaker 1: stuff we've we've observed in the universe, then the densest
• 39:47
  Speaker 1: black hole we've observed is not as dense as neutron
• 39:51
  Speaker 1: stars because we've never seen one smaller than six solar
• 39:55
  Speaker 1: masses and I have to be smaller than that to
• 39:57
  Speaker 1: be denser. But so why haven't we seen one? Could
• 40:00
  Speaker 1: one exist? They certainly could exist. Yeah, there's no minimum
• 40:04
  Speaker 1: size to a black hole. Remember, at the large Hadron Collider,
• 40:06
  Speaker 1: we think we might create black holes and those black
• 40:08
  Speaker 1: holes would be like particle sized, So there's no minimum
• 40:12
  Speaker 1: size to a black hole. So they certainly could exist.
• 40:14
  Speaker 1: There could be black holes out there that are the
• 40:16
  Speaker 1: mass of the Sun, or half the mass of the Sun,
• 40:18
  Speaker 1: or the mass of one Horge for example. They could exist,
• 40:21
  Speaker 1: but they're harder to see, right. Smaller black holes are
• 40:24
  Speaker 1: harder to see. So the densest thing in any of
• 40:26
  Speaker 1: the universe is probably a black hole, but it would
• 40:30
  Speaker 1: have to a be a small black hole less massive
• 40:35
  Speaker 1: than our sun and be we haven't seen what. So
• 40:39
  Speaker 1: technically the densest thing we've seen is a neutron star.
• 40:43
  Speaker 1: But the densest thing that could exist is a small
• 40:45
  Speaker 1: black hole unless you're willing to pierce the veil of
• 40:48
  Speaker 1: the event horizon and talk about what's going on inside
• 40:51
  Speaker 1: the black hole. What's inside a hole? Right, Well, then
• 40:56
  Speaker 1: that's the thing we don't know right now. Originally, Einstein
• 40:59
  Speaker 1: and general Relative they say, in the center of a
• 41:01
  Speaker 1: black hole is a singularity is a point, and a
• 41:04
  Speaker 1: singularity means a point of infinite density, right, at a
• 41:07
  Speaker 1: point where there is a huge amount of mass in
• 41:10
  Speaker 1: zero volume, which is pretty hard to get your mind around,
• 41:13
  Speaker 1: like how do you have stuff in no space? But
• 41:15
  Speaker 1: black holes are hard to get your mind around anyway,
• 41:18
  Speaker 1: So that's what Einstein would say. I would say, Oh,
• 41:20
  Speaker 1: the answer this question is obvious, it's the singularity inside
• 41:22
  Speaker 1: a black hole. But but que quantum mechanics, and he
• 41:26
  Speaker 1: wouldn't say that. His spokesperson would say that, I guess
• 41:31
  Speaker 1: um Foundation, that's right, the estate of Albert Einstein Um.
• 41:36
  Speaker 1: But the quantum mechanics folks would say, look, we know
• 41:39
  Speaker 1: the universe is quantum mechanical, and quantum mechanics says, you
• 41:42
  Speaker 1: can't have that much stuff in a well defined location, right.
• 41:46
  Speaker 1: Quantum mechanics says, we know there can't be a singularity
• 41:48
  Speaker 1: at the center of black holes. We don't know what's there,
• 41:50
  Speaker 1: we don't know how it works, we don't know what's
• 41:52
  Speaker 1: going on. And at that point gravity gets so strong
• 41:55
  Speaker 1: that our theories of quantum mechanics don't work, and we
• 41:57
  Speaker 1: don't have a theory of quantum mechanics that work when
• 42:00
  Speaker 1: gravity is really really powerful um, So it's a big mess.
• 42:04
  Speaker 1: We don't know what's going on inside a black hole.
• 42:06
  Speaker 1: If it's if general relativity is correct, which we're pretty
• 42:09
  Speaker 1: sure it's not, then there's an infinite density singularity. If
• 42:13
  Speaker 1: quantum mechanics is correct, which we think it is, but
• 42:16
  Speaker 1: it doesn't work inside a black hole, then we don't know.
• 42:18
  Speaker 1: So what's the densest thing in the universe? Apparently it's
• 42:21
  Speaker 1: the ignorance of physicists. We don't really know i'near these things.
• 42:28
  Speaker 1: We have no idea, that's the answer. We have no
• 42:30
  Speaker 1: idea what the densest thing in the universe is. It
• 42:32
  Speaker 1: could be a neutron star. It could be a small
• 42:35
  Speaker 1: black hole, It could be a singularity at the center
• 42:37
  Speaker 1: of a black hole. It could be something else weird
• 42:39
  Speaker 1: and quantum mechanical that's going on inside a black hole.
• 42:42
  Speaker 1: We just don't know, all right. So that so that's
• 42:44
  Speaker 1: the answer to what is the dnist thing at the
• 42:45
  Speaker 1: universe is? We don't know exactly, and it kind of
• 42:48
  Speaker 1: depends on what we've observed and what the true theory
• 42:53
  Speaker 1: of physics is at these extreme situations. That's right. But
• 42:57
  Speaker 1: the densest thing we've ever found is a neutrons are,
• 43:00
  Speaker 1: which is plenty dance to impress you about extreme densities
• 43:04
  Speaker 1: in the universe, right, it goes from like a proton
• 43:08
  Speaker 1: in a teaspoon up to a million Eiffel towers in
• 43:11
  Speaker 1: the teaspoon. So there's an enormous range of densities. You know.
• 43:14
  Speaker 1: The universe is not just like uniform and spread out right,
• 43:17
  Speaker 1: it's like mostly empty with these incrediblely tight packed pockets.
• 43:22
  Speaker 1: And that works even in France. That works email in France,
• 43:25
  Speaker 1: exactly all right. Thanks for joining us and another one
• 43:28
  Speaker 1: of our Extreme Universe series. We hope you enjoyed that.
• 43:31
  Speaker 1: Thanks for tuning in, and hey, if you have a
• 43:33
  Speaker 1: question about the universe or or want us to talk
• 43:36
  Speaker 1: about another extreme thing in the universe, let us know.
• 43:46
  Speaker 1: If you still have a question after listening to all
• 43:48
  Speaker 1: these explanations, please drop us a line. We'd love to
• 43:52
  Speaker 1: hear from you. You can find us at Facebook, Twitter,
• 43:54
  Speaker 1: and Instagram at Daniel and Jorge That's one word, or
• 43:58
  Speaker 1: email us at Feedback Daniel and Jorge dot com. Thanks
• 44:02
  Speaker 1: for listening and remember that Daniel and Jorge Explain the
• 44:05
  Speaker 1: Universe is a production of I Heart Radio. For more
• 44:08
  Speaker 1: podcast from my Heart Radio, visit the i Heart Radio app,
• 44:12
  Speaker 1: Apple Podcasts or wherever you listen to your favorite shows,