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Speaker 1: Hey, Daniel, do you enjoy doing housework?

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Speaker 2: There's something satisfying about it compared to the abstraction of research.

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Speaker 2: You know, you start doing dishes and then the dishes

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Speaker 2: are done.

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Speaker 1: Yeah, that's a cost and effect, right, basic law of

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Speaker 1: the universe. If you wash the dishes, they will presumably

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Speaker 1: be clean.

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Speaker 2: I wish that same thing applied to physics research. You know,

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Speaker 2: you do the physics research and the mysteries are unraveled.

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Speaker 2: Doesn't know what's happened that way.

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Speaker 1: Well, there's no guarantee in science.

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Speaker 2: How about you. Are you a fan of housework?

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Speaker 1: Uh? No, And yet I'm the person who does all

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Speaker 1: the dishes in my house. Well, actually the dishwasher doesn't,

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Speaker 1: but I assist the dishwasher. I'm the assistant dishwasher.

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Speaker 2: And are you a fan of vacuuming?

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Speaker 1: I'm not a huge fan.

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Speaker 2: No.

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Speaker 1: I mean, I think my vacuum has a big fan,

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Speaker 1: but I am not a fan of vacuuming.

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Speaker 2: I agree vacuuming totally sucks.

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Speaker 1: Hi. I'm Horium, my cartoonist and the author of all

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Speaker 1: ours great big Universe.

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Speaker 2: Hi. I'm Daniel. I'm a particle physicist and a professor

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Speaker 2: at U. See Irvine, and sometimes I feel like my

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Speaker 2: head contains a perfect vacuum.

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Speaker 1: You mean, like a perfect vacuuming machine or a perfect

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Speaker 1: lack of pressure.

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Speaker 2: You know how, sometimes you reach back into your mind

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Speaker 2: for a good idea and you just find nothing. On

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Speaker 2: the other hand, you know, maybe that means you're ready

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Speaker 2: to suck in a bunch of new information.

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Speaker 1: M I thought you were saying your brain sucks.

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Speaker 2: The creative process is a mystery to me.

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Speaker 3: You know.

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Speaker 2: Sometimes you reach back there and you find gold, and

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Speaker 2: other times you are just left empty handed.

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Speaker 1: It is pretty dusty inside of my head as well.

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Speaker 1: But anyways, welcome to our podcast, Daniel and Horror I

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Speaker 1: Explained Universe, a production of iHeartRadio.

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Speaker 2: In which we try to take the whole universe and

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Speaker 2: squeeze it into your brain, hoping that there's enough space

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Speaker 2: to contain all of its mysteries, all of its majesty,

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Speaker 2: all of its marvelous contents, including quantum particles, including black holes,

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Speaker 2: including neutron stars, including photons, and everything else that makes

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Speaker 2: this universe a wonderful, delicious and bizarre place to live.

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Speaker 1: That's right. It is science's job to dig down into

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Speaker 1: the dusty corners of the universe and polish off our

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Speaker 1: knowledge about how things work and why things are the

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Speaker 1: way they are.

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Speaker 2: And when scientists think about dust, we're not always just

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Speaker 2: thinking about it as an annoyance, something to get rid of. Instead,

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Speaker 2: we want to take the universe apart into its smallest pieces,

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Speaker 2: and so dust provides a very useful clue. What is

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Speaker 2: dust made out of? What happens when we break dust

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Speaker 2: open into smaller bits? Why is the universe so dusty? Anyway?

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Speaker 1: So we are actually technically all made out of star dust, right,

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Speaker 1: isn't that what the famous saying from Carl Sagan?

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Speaker 2: That is the famous saying. And you know it's mostly true.

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Speaker 2: All the heavier elements we were made of, at least

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Speaker 2: were composed in the hearts of stars out there, fusing

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Speaker 2: together the primordial hydrogen and helium created during the Big Bang.

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Speaker 2: But since a large part of our bodies are made

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Speaker 2: of hydrogen, part of us are actually Big Bang dust,

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Speaker 2: not just star dust.

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Speaker 1: I guess maybe since atoms are all made of the

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Speaker 1: same things, technically, like, it's just more and more dust,

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Speaker 1: kind of compounded dust that we're made out of.

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Speaker 2: Jorges Dusty theory of the Universe.

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Speaker 1: Now, does that mean that bunnies are also made out

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Speaker 1: of dust bunnies?

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Speaker 2: Or are dust bunnies made out of bunnies?

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Speaker 1: How about people named dusty? Would they also be made

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Speaker 1: out of star dust?

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Speaker 2: Star dust and bang dust? And while it's fun to

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Speaker 2: make these jokes, it's also really a fascinating mystery, like

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Speaker 2: what is all of this stuff? What is its fundamental nature?

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Speaker 2: Deep down? And that question is sitting inside a deeper, broader,

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Speaker 2: maybe even emptierestion, which is like, what is all of

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Speaker 2: this stuff sitting in? What happens to the universe if

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Speaker 2: you get rid of all the dust, you finally suck

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Speaker 2: it all away and reveal the nothingness? What is all

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Speaker 2: of that nothingness?

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Speaker 1: That's right? What is nothing? Is it nothing? Or is

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Speaker 1: nothing something?

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Speaker 2: Do we have nothing to say about it? And can

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Speaker 2: we anyway spin it into a forty five minute podcast?

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Speaker 1: No, let's just create an audio vacuum right now for

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Speaker 1: forty five minutes. Ready go.

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Speaker 2: That's actually a great analogy for today's podcast because even

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Speaker 2: in that quiet, pun free moment, there was not nothing.

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Speaker 2: There was something.

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Speaker 1: So today on the podcast, we'll be asking the question

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Speaker 1: what is a vacuum?

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Speaker 2: Now?

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Speaker 1: I imagine Daniel, you mean like a space vacuum, not

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Speaker 1: like a household vacuum.

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Speaker 2: I do love digging into the physics of everyday objects,

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Speaker 2: because it turns out there's always a surprising amount of

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Speaker 2: complicated physics that goes into like what is a mirror?

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Speaker 2: Or how does glass work? This kind of stuff is

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Speaker 2: super fun. But no, today, I want to talk about

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Speaker 2: the nothingness of the universe. What happens if you use

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Speaker 2: a vacuum to suck up all this stuff? What is

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Speaker 2: that vacuum? And philosophically, what does that mean about the

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Speaker 2: nature of reality?

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Speaker 1: Yeah, and I guess more fundamentally, does a vacuum exist?

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Speaker 1: Is it possible to actually have nothing in the universe?

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Speaker 2: Or is it possible to have multiple different vacuums or

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Speaker 2: vacuum a.

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Speaker 1: Or maybe more a trippy Is a vacuum something.

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Speaker 2: Or if a vacuum is something, maybe that's just what

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Speaker 2: we define as nothing as the most vacuum meist something.

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Speaker 1: Okay, now I'm getting nothing out of this.

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Speaker 2: I just invented a word vacuumist. Vacuumist, though it sounds

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Speaker 2: more like somebody who operates a vacuum. Maybe it's not

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Speaker 2: the best choice.

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Speaker 1: Well, that would be a vacuumer, wouldn't it be?

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Speaker 2: Not an expert in naming things over here?

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Speaker 1: Very clearly, But anyways, as usual, we were wondering how

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Speaker 1: many people out there had thought about this fundamental question

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Speaker 1: what is a vacuum and if they have any ideas

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Speaker 1: about whether it is something or nothing.

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Speaker 2: So thanks very much to everybody out there who answers

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Speaker 2: these questions for the podcast. And if you've been listening

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Speaker 2: for a while or even just a few weeks and

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Speaker 2: you'd like to throw your hat into the ring, everybody's welcome,

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Speaker 2: please write to me two questions at Danielandjorge dot com.

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Speaker 1: So think about it for a second. What do you

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Speaker 1: think a vacuum is? Here's what people have to say.

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Speaker 4: It sounds like the inside of my head when you

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Speaker 4: ask this question, But if I were to think of it,

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Speaker 4: vacuum is like a whiteboard with infinite possibilities, And when

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Speaker 4: something comes along, like a whiteboard marker, you can either

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Speaker 4: draw stuff on it or you can just raise stuff

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Speaker 4: on it.

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Speaker 1: It's just everything.

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Speaker 5: The vacuum would be space without any stuff in it,

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Speaker 5: like no atmosphere, but I think space always has some

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Speaker 5: stuff in it, so it's not really a true vacuum.

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Speaker 5: That's really all I know.

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Speaker 1: I'm pretty sure the vacuum is like space with all

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Speaker 1: its quantum fields, like at its resting state.

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Speaker 3: I can guess by what it says the vacuum is

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Speaker 3: not a vacuum cleaner, but the vacuum of space. What

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Speaker 3: causes it is actually a good question. I don't know.

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Speaker 3: Maybe it's something related to dark energy and expansion, but

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Speaker 3: probably not.

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Speaker 4: I think vacuum is the definition, the theoretical definition of

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Speaker 4: the absence of matter in a given space.

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Speaker 6: I think vacuum quite literally means emptiness or absence of stuff. Now,

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Speaker 6: if you have a bottle, you remove everything from it,

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Speaker 6: then you have a vacuum. But I think that's pretty ideal.

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Speaker 2: I don't think you can actually remove everything from a bottle.

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Speaker 6: Vacuum is the absence of matter, but I know that

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Speaker 6: it doesn't mean it's empty, and there are lots of

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Speaker 6: quantum craziness going around in what we traditionally call vacuum.

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Speaker 6: So I'm looking forward for your guys to explain it.

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Speaker 1: All right, A lot of interesting answers here. Someone got

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Speaker 1: kind of technical talking about fields and resting states, the

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Speaker 1: absence of matter.

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Speaker 2: M m lots of really cool answers here that explore

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Speaker 2: really the wide spectrum of possibilities for what nothing is.

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Speaker 1: Yeah, I guess you could define it in several ways, right,

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Speaker 1: like absence of matter or absence of energy, or absence

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Speaker 1: of quantum field maybe.

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Speaker 2: Yeah, And we will tear all of that apart on

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Speaker 2: the podcast today.

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Speaker 1: Well, let's dig into it, Daniel. How does physicists define

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Speaker 1: what a vacuum is?

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Speaker 2: So, the definition of a vacuum, from the point of

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Speaker 2: view of physics and especially quantum field theory, is space

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Speaker 2: with no particles in it. Essentially space as empty as

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Speaker 2: possible from energy. If you can stuck all the energy out,

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Speaker 2: including the matter, and relax space down to its lowest

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Speaker 2: energy state, that's what we consider a vacuum.

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Speaker 1: Now, how is it different than the concept of space itself.

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Speaker 1: Is space the vacuum or can space be a vacuum?

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Speaker 2: Well, there's the difference between space and sort of empty space.

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Speaker 2: Space itself doesn't have to be a vacuum. Like at

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Speaker 2: the heart of the Sun. There's space, right, there's all

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Speaker 2: sorts of particles bouncing around, whizzing around, incredible density, very

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Speaker 2: high temperature, lots of matter loss of energy. All of

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Speaker 2: that sits within space. Right, the Sun is in space.

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Speaker 2: Even the heart of the Sun has space within it.

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Speaker 2: It's not empty space. It's very high energy, very dense space.

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Speaker 2: As you move away from the Sun, of course, that

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Speaker 2: space gets lower and lower energy, fewer particles. But everywhere

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Speaker 2: in the universe we think has space in it.

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Speaker 1: You mean everywhere in space has space in it.

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Speaker 2: Yeah. As soon as you use the word where, you're

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Speaker 2: assuming a location and location requires space. You can't really

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Speaker 2: have locations without space. Space represents the relationships between points, right,

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Speaker 2: That's really what space is.

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Speaker 1: I guess can you have the universe without space or

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Speaker 1: space without universe?

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Speaker 2: You might be able to have the universe without space

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Speaker 2: because we don't fundamentally know what space itself is. We

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Speaker 2: don't know if it's a necessary fundamental part of the universe,

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Speaker 2: meaning that like it has to exist, or if it's

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Speaker 2: an emergent property of something deeper, you know, something that

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Speaker 2: just sort of gets woven together out of the fundamental

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Speaker 2: bits of the universe that might not require space. If

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Speaker 2: you're not familiar with the concept of like fundamental versus emergent,

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Speaker 2: fundamental just means it's required, it's essential, whereas emergent means

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Speaker 2: it's not that. Sometimes it happens and sometimes it doesn't.

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Speaker 2: Like ice cream and pies we think are emergent properties

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Speaker 2: or something the universe can do, they can't exist. But

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Speaker 2: it's possible to have a universe without ice cream and pies.

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Speaker 2: So we think it might be possible to have a

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Speaker 2: universe without space, though that's not something we understand. There

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Speaker 2: are various theories out there, but that's an open question

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Speaker 2: in physically, so far we're operating under the assumption that

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Speaker 2: space is essential for the universe.

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Speaker 1: Well, I don't know about physics, but ice cream is

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Speaker 1: pretty essential to my life. I mean, a universe without

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Speaker 1: ice cream it's not a universe I want to live in.

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Speaker 2: And yet the vast majority of the history of the

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Speaker 2: universe had exactly zero ice cream in it, unless, of course,

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Speaker 2: there are ancient alien civilizations who also enjoyed cold custards.

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Speaker 1: We don't know. So you're saying you don't know if

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Speaker 1: aliens have ice cream or not. It's still an open question.

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Speaker 2: I can make no definitive statement about alien ice cream

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Speaker 2: that is exactly true.

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Speaker 1: Yes, Also, I think in a vacuum, no one can

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Speaker 1: hear you ice cream. You're like, I don't even know

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Speaker 1: where to go with that joke.

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Speaker 2: That was the perfect joke. There's no possible response to it.

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Speaker 2: A vacuum is there only possible response to that joke.

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Speaker 1: That's right, it's a micdrop moment.

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Speaker 2: Boom, Exactly, I just dropped my ice cream over here.

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Speaker 2: It's an ice cream drop moment.

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Speaker 1: But ana is back to our discussion. So you're saying

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Speaker 1: a vacuum is space with no matter in it, no

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Speaker 1: particles in it.

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Speaker 2: Yeah, that's exactly right. Whereas the minimum energy which includes particles. Right,

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Speaker 2: if you're talking about what space is, space is fundamentally

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Speaker 2: something we don't understand, but it has inside of it

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Speaker 2: the possibility to contain all sorts of energy and matter.

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Speaker 2: You can have protons in space. You can have photons

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Speaker 2: in space. Photons are not technically matter, they fall into

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Speaker 2: the radiation category. Right, So you can all sorts of

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Speaker 2: different kinds of energy inside of space, and we have

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Speaker 2: a huge variety of energy. Density in space. Right around

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Speaker 2: us on Earth is an incredible number of particles. You

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Speaker 2: take a cubic meter of air just in front of

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Speaker 2: you here on Earth, and there's like ten to the

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Speaker 2: twenty five mongules in that cubic meter of air. It's

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Speaker 2: like swarming with particles.

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Speaker 1: Well, I guess you know, for me traditional Newtonian kind

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Speaker 1: of high school physics, or you know, kind of as

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Speaker 1: we grow up kind of way. A particle are bits

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Speaker 1: of stuff that can fly around or float around, and

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Speaker 1: so it's kind of easy to imagine just a chunk

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Speaker 1: of space, a Cuba space, with no little bits in it. Right,

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Speaker 1: that would be a vacuum in a traditional sense.

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Speaker 2: In a traditional sense depending on whether you're including radiation also, right,

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Speaker 2: To really get a vacuum, you want to minimize the

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Speaker 2: overall energy, not just the total matter. So yeah, you

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Speaker 2: want to apply your vacuum and suck out all the bits.

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Speaker 2: But then you also want to prevent photons and other

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Speaker 2: kinds of non matter radiation from entering that cube of

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Speaker 2: space to get the best vacuum you can get.

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Speaker 1: Well, radiation is also particles, right, Like a photon is

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Speaker 1: a particle.

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Speaker 2: A photon is a particle, but it's not matter in

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Speaker 2: the same sense. These are like silly overlapping definitions. So yeah,

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Speaker 2: if you suck out all the particles, that would include photons.

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Speaker 2: So yes, that would be all the radiation.

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Speaker 1: But I guess it's complicated because now we know that

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Speaker 1: a particle is really just like a little blip in

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Speaker 1: a quantum field. Right.

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Speaker 2: So there are sort of two different philosophical pictures about

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Speaker 2: how this all works, and one that we talk about

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Speaker 2: on the podcast a lot is what you just described,

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Speaker 2: which is to meagine particles themselves as emergent properties. They're

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Speaker 2: not fundamental things in the universe. They're just eagles in

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Speaker 2: these fields that fill all of space. And in that picture,

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Speaker 2: fields are the most fundamental thing that when you have space,

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Speaker 2: it contains these fields. And these fields are like places

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Speaker 2: that energy can be. They're like, you know, how you

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Speaker 2: can stack energy up and if you wiggle them in

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Speaker 2: just the right way, then we call that a particle.

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Speaker 2: So that's sort of one picture of the structure of space, time,

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Speaker 2: and matter. There's another picture which says fields are nonsense.

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Speaker 2: Really everything is made of particles, and the way particles

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Speaker 2: communicate with each other and exchange momentum and stuff is

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Speaker 2: by exchanging other particles. So the sort of the fields picture,

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Speaker 2: which I think is more popular and maybe more intuitive,

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Speaker 2: But there is also this other picture that says that

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Speaker 2: particles are the most fundamental thing, and fields are nonsense

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Speaker 2: because remember, we never actually see fields themselves. Fields are

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Speaker 2: sort of a unobserved story. We tell ourselves to explain

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Speaker 2: what we do see in the universe, but we never

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Speaker 2: actually see them. We only see their effect on particles.

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Speaker 1: Fields are sort of like the potential for particles to happen.

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Speaker 2: Yeah, there's sort of like the parking lot into which

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Speaker 2: you can put cars, right, but again, we can't ever

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Speaker 2: see them directly, like even electric field which don't seem

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Speaker 2: controversial as a topic, like do electric fields exist? Well,

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Speaker 2: how do you see an electric field? You put an

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Speaker 2: electron in it and you see it move. What you're

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Speaker 2: really seeing is the electron moving, not the field itself,

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Speaker 2: So it's sort of a little bit indirect.

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Speaker 1: Well, maybe we're getting a little bit ahead of ourselves.

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Speaker 1: I think what you're saying is that the idea that

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Speaker 1: a vacuum is just a chunk of space without particles

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Speaker 1: in it's still or energy is still pretty good.

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Speaker 2: Yeah, that's a pretty good concept of what a vacuum is,

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Speaker 2: though it's surprisingly rare in the universe and hard to achieve.

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Speaker 1: Well, I guess maybe the first question or listeners might

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Speaker 1: have is is space out there really a vacuum.

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Speaker 2: It's hard for me to say that anywhere in the

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Speaker 2: universe is actually a true vacuum. If you go like

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Speaker 2: near the surface of the Earth where space officially starts,

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Speaker 2: which is like one hundred kilometers above the surface of

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Speaker 2: the Earth, although the United States calls you an astronaut,

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Speaker 2: if you've been above eighty kilometers, then that's where space

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Speaker 2: officially starts. But there's a lot of stuff out there still.

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Speaker 2: You know, the Earth's atmosphere doesn't end. It's not like

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Speaker 2: there's a pane of glass there that's holding the atmosphere

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Speaker 2: and it should drifts off gradually. So there's still a

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Speaker 2: lot of atmosphere up there. And if you fly your

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Speaker 2: satellite at that orbit, you'll be dragged by that atmosphere

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Speaker 2: and eventually you deorbit back to the Earth's surface. So

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Speaker 2: we know that there's definitely a lot of stuff out

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Speaker 2: there still.

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Speaker 1: Just about the Earth or just outside of the Earth.

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Speaker 1: It's kind of you say, it's kind of hard to

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Speaker 1: find a true vacuum.

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Speaker 2: And so you go further, right like, Okay, I'm gonna

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Speaker 2: leave Earth entirely, I'm gonna go into interplanetary space. Halfway

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Speaker 2: between Earth and Mars. Well, then there's still a lot

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Speaker 2: of stuff out there. You know, the Sun pumps out

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Speaker 2: not just photons which we consider energy and particles and

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Speaker 2: so it disrupts your vacuum, but also matter particles, electrons, protons,

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Speaker 2: alpha particles, very very high speed particles moving on like

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Speaker 2: hundreds of kilometers per second. And there's not a tiny

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Speaker 2: number of them. There's like millions of protons per cubic

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Speaker 2: meter out there in interplanetary space.

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Speaker 1: Whoa coming from the Sun, right.

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Speaker 2: Yeah, this is the solar wind. And you know that's

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Speaker 2: a tiny number compared to the density of air here

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Speaker 2: on Earth. It's like ten to the nineteen times less dense.

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Speaker 2: So it feels like a vacuum if somebody chucks you

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Speaker 2: out the air lock, But it's not even really close

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Speaker 2: to a vacuum because you still have millions of particles

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Speaker 2: per cubic meter.

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Speaker 1: Well, what if you go out further into space. Can

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Speaker 1: you find a true vacuum out there?

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Speaker 2: If you like leave the Solar System and go into

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Speaker 2: interstellar space, still inside the galaxy, then you're still surrounded

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Speaker 2: by what we call the interstellar medium, which is mostly

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Speaker 2: gas and a little bit of dust some cosmic rays,

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Speaker 2: and here it's much more sparse and it's highly variable.

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Speaker 2: You can get from like ten to the minus four

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Speaker 2: up to ten to the six molecules per cubic meter,

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Speaker 2: so it's still really not close to empty. And don't

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Speaker 2: forget that's just the kind of matter we know about, right,

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Speaker 2: protons and electrons. There's still also the dark matter, which

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Speaker 2: is filling the galaxy. Inside the galley, we're inside the

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Speaker 2: dark matter halo, which is five times as much matter

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Speaker 2: as the normal matter. So inside the galaxy you can't

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Speaker 2: really ever say you have a vacuum.

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Speaker 1: What about like the far reaches of space, Like if

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Speaker 1: you go deep out there in the middle of nowhere,

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Speaker 1: really in the middle of nowhere between galaxies.

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Speaker 2: So take a point, for example, between the Milky Way

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Speaker 2: and Andromeda. You're far outside of the galaxy. There's still

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Speaker 2: something there. There's the intergalactic medium. This is a rarefied plasma.

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Speaker 2: It's mostly protons and it's not zero. There's like one

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Speaker 2: to ten atoms per cubic meter, and there's actually kind

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Speaker 2: of a lot of stuff out there, this plasma that's

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Speaker 2: between galaxies. This number sort of shocks me. Is about

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Speaker 2: half of the ordinary matter in the universe. Like you

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Speaker 2: look up at the night sky and you see stars,

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Speaker 2: and you think about galaxies, and you know, there's a

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Speaker 2: lot of dark matter out there that we can't see,

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Speaker 2: but you imagine probably we're seeing all the normal matter.

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Speaker 2: But something like half fifty percent of all the normal

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Speaker 2: matter in the universe is between galaxies, any sort of

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Speaker 2: filaments of plasma that connects them together.

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Speaker 1: Yeah, because these filaments are huge, right, Like the space

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Speaker 1: between galaxies and clusters of galaxies. It's a lot. So

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Speaker 1: even if you only have one to ten atoms per

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Speaker 1: cubic meter, it adds up to as you're saying, half

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Speaker 1: of the stuff in the universe.

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Speaker 2: Yeah, it's really a lot of stuff. But you can

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Speaker 2: get more sparse. Right, You're like, let's not hang out

390
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Speaker 2: between the galaxies. Let's leave the galactic cluster, or let's

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Speaker 2: find one of these supervoids that are between the superclusters.

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Speaker 2: Right and out there is the closest you can get

393
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Speaker 2: to a vacuum. You know, the number density of particles,

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Speaker 2: the particles per cubic meter drops to almost zero. There's

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Speaker 2: almost no photons out there either. It's like as close

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Speaker 2: to zero as you can.

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Speaker 1: Get wait, isn't that weird? Like how can you have

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Speaker 1: no photons? Like you'd be there and you would look

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Speaker 1: out around you and you wouldn't see anything.

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Speaker 2: It'll never actually get to zero. Right, You'll be as

401
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Speaker 2: distant as possible from all of those galaxies, and so

402
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Speaker 2: you'll have the dimmest view of all of them. But

403
00:20:00,520 --> 00:20:03,320
Speaker 2: you're right, it'll never actually get to zero. Right. It's

404
00:20:03,320 --> 00:20:06,280
Speaker 2: not like you look around you and you see total blackness.

405
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Speaker 2: So the number of photons will never actually get to zero,

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Speaker 2: even inside those supervoids. It's like the furthest you can

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Speaker 2: get from all the light sources. It's like if you're

408
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Speaker 2: trying to find a dark spot in your city to

409
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Speaker 2: look at the night sky, and you get as far

410
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Speaker 2: away as possible from all the street lights, you're still

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Speaker 2: going to have some light there.

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Speaker 1: Are you trying to say that there is no perfect

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Speaker 1: vacuum in the universe, naturally occurring perfect vacuum in the universe.

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Speaker 1: It's not possible to find a perfect vacuum.

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Speaker 2: It's probably impossible for all of those reasons. I think

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Speaker 2: every chunk of space probably has at least one photon

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Speaker 2: in it from some distant galaxy that threw that particle

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Speaker 2: in that direction.

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Speaker 1: But that's kind of an average though, right, Like, maybe

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Speaker 1: when you're out there, you see a photon every once

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Speaker 1: in a while, but in between the times that you

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Speaker 1: see a photon, you would be sort of in a

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Speaker 1: perfect vacuum potentially.

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Speaker 2: And here's where we run up against the technical question,

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Speaker 2: because every chunk of space also contains dark energy, right.

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Speaker 2: Dark energy not something we understand, but every chunk of

427
00:21:04,640 --> 00:21:07,560
Speaker 2: space has some of it. So the technical definition of

428
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Speaker 2: a vacuum is not space with no energy in it.

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Speaker 2: It's space with a minimum amount of energy. So you

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Speaker 2: can be in a chunk of space that has some

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Speaker 2: energy in it and still call that a vacuum if

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Speaker 2: you're convinced that that's the most relaxed possible state of space.

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Speaker 1: Hmm. It sounds like maybe there's a concept of a

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Speaker 1: perfect vacuum, and then there's a concept of like what's

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00:21:28,040 --> 00:21:32,560
Speaker 1: the minimum vacuum that the universe naturally has out there?

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00:21:32,640 --> 00:21:35,359
Speaker 1: You know, kind of like temperature, right, Like there's absolute zero,

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Speaker 1: and then there's what actually actually seen the universe.

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Speaker 2: There's what space theoretically could accomplish in terms of relaxation,

439
00:21:42,280 --> 00:21:45,040
Speaker 2: and then there's this sort of most relaxed space that

440
00:21:45,160 --> 00:21:48,040
Speaker 2: actually exists in the universe, and those could be different.

441
00:21:48,440 --> 00:21:52,440
Speaker 1: Hmm. All right, so let's get into what would actually

442
00:21:52,480 --> 00:21:55,200
Speaker 1: happen if you create a perfect vacuum in the universe.

443
00:21:55,320 --> 00:21:57,840
Speaker 1: What would that mean? Is it possible and would it

444
00:21:57,880 --> 00:22:00,360
Speaker 1: be as tidy as we want it to be? Dig

445
00:22:00,400 --> 00:22:15,280
Speaker 1: into that, But first let's take a quick break. All right,

446
00:22:15,320 --> 00:22:17,920
Speaker 1: we're talking about vacuuming the universe. It sounds like the

447
00:22:18,200 --> 00:22:20,480
Speaker 1: universe has a lot of space that you need to

448
00:22:20,960 --> 00:22:21,440
Speaker 1: suck up.

449
00:22:22,320 --> 00:22:25,480
Speaker 2: It's a big chore to clean up the whole universe.

450
00:22:25,680 --> 00:22:27,800
Speaker 1: Now, is the universe more of like a shag carpet

451
00:22:28,160 --> 00:22:30,920
Speaker 1: or you think it's more of a wooden floors kind

452
00:22:30,960 --> 00:22:31,480
Speaker 1: of situation.

453
00:22:31,760 --> 00:22:35,360
Speaker 2: I think it'd be pretty hard to totally thoroughly cleanse

454
00:22:35,440 --> 00:22:38,080
Speaker 2: the universe, So yeah, it's definitely shag carpeting out there.

455
00:22:38,280 --> 00:22:40,800
Speaker 1: Or maybe right like, we don't know if maybe the

456
00:22:40,880 --> 00:22:43,960
Speaker 1: universe encompasses all of the matter in the universe, or

457
00:22:44,000 --> 00:22:45,840
Speaker 1: maybe there's a bunch of universe out there that is

458
00:22:45,880 --> 00:22:46,520
Speaker 1: truly empty.

459
00:22:46,760 --> 00:22:50,439
Speaker 2: It's possible, though cosmologists prefer the assumption that the universe

460
00:22:50,520 --> 00:22:53,479
Speaker 2: is essentially the same everywhere. It's not a totally solid

461
00:22:53,520 --> 00:22:56,240
Speaker 2: experimental point, but it's sort of the simplest idea that

462
00:22:56,280 --> 00:22:58,520
Speaker 2: there's no special place in the universe. And so when

463
00:22:58,560 --> 00:23:02,560
Speaker 2: you zoom out really far and cosmic scales, we see

464
00:23:02,600 --> 00:23:05,040
Speaker 2: so far the universe has the same density of stuff

465
00:23:05,080 --> 00:23:08,760
Speaker 2: basically everywhere, again massively zooming out right on the scale

466
00:23:08,760 --> 00:23:11,640
Speaker 2: of superclusters of galaxies. So that would suggest that there

467
00:23:11,680 --> 00:23:15,440
Speaker 2: isn't any place in space that's like really truly specially empty,

468
00:23:15,480 --> 00:23:17,920
Speaker 2: different from the part of the universe that we find

469
00:23:17,960 --> 00:23:20,320
Speaker 2: ourselves in. So that's just an assumption, right, which is

470
00:23:20,359 --> 00:23:23,399
Speaker 2: extrapolating from what we see out to infinity, which is

471
00:23:23,440 --> 00:23:24,280
Speaker 2: always dangerous.

472
00:23:24,760 --> 00:23:28,800
Speaker 1: Yeah. I think sometimes people talk about the analogy with

473
00:23:28,960 --> 00:23:30,879
Speaker 1: like fish in the water, right, Like you could be

474
00:23:30,920 --> 00:23:32,959
Speaker 1: a fish at the bottom of the ocean and think, oh,

475
00:23:33,320 --> 00:23:35,560
Speaker 1: the whole universe is filled with water, right, because as

476
00:23:35,600 --> 00:23:36,880
Speaker 1: far as I can see, there's water.

477
00:23:38,840 --> 00:23:41,120
Speaker 2: Yeah, that's right. I think that's Max tech Mark's analogy,

478
00:23:41,160 --> 00:23:43,480
Speaker 2: which is really wonderful because it gives you a sense

479
00:23:43,560 --> 00:23:46,520
Speaker 2: of your naivete and how you might not know what

480
00:23:46,600 --> 00:23:49,320
Speaker 2: you don't know. And there could of course be boundaries

481
00:23:49,640 --> 00:23:52,080
Speaker 2: to the kind of universe that you imagine we could

482
00:23:52,080 --> 00:23:54,800
Speaker 2: be living in a bubble where these laws of physics

483
00:23:54,800 --> 00:23:57,720
Speaker 2: apply and everything seems to make sense to us, but

484
00:23:57,760 --> 00:23:59,680
Speaker 2: there could be an edge to it out past, which

485
00:23:59,800 --> 00:24:03,440
Speaker 2: the universe is in another phase, you know, crazy densities

486
00:24:03,480 --> 00:24:07,199
Speaker 2: where quantum gravity applies, or maybe the inflaton field hasn't

487
00:24:07,200 --> 00:24:10,960
Speaker 2: decayed yet, or some other crazy nosis, so it's always possible.

488
00:24:11,240 --> 00:24:13,919
Speaker 1: Or maybe we're living inside of a vacuum of someone

489
00:24:13,960 --> 00:24:17,280
Speaker 1: cleaning up their universe in a super mega universe.

490
00:24:17,400 --> 00:24:19,480
Speaker 2: Man, that would totally suck so well.

491
00:24:19,520 --> 00:24:21,840
Speaker 1: As you were saying earlier, it's kind of hard to

492
00:24:21,880 --> 00:24:25,040
Speaker 1: find a naturally occurring perfect vacuum because even if you're

493
00:24:25,080 --> 00:24:29,400
Speaker 1: out there in the depth of space in between galactic clusters,

494
00:24:29,440 --> 00:24:31,320
Speaker 1: there's stills kind of stuff in it. There might be

495
00:24:31,359 --> 00:24:33,840
Speaker 1: some a little bit of light or an atom here

496
00:24:33,920 --> 00:24:37,160
Speaker 1: or there, or maybe even dark energy or dark matter.

497
00:24:37,400 --> 00:24:39,960
Speaker 2: Right, Yeah, that's right. It's hard to find a chunk

498
00:24:40,000 --> 00:24:44,080
Speaker 2: of space that really has no particles in it because

499
00:24:44,119 --> 00:24:47,680
Speaker 2: the universe is buzzing with stuff and that's flying everywhere

500
00:24:47,760 --> 00:24:48,960
Speaker 2: and filling everything up.

501
00:24:49,359 --> 00:24:51,680
Speaker 1: So then I guess the next question that we can

502
00:24:51,720 --> 00:24:57,040
Speaker 1: ask is is the perfect vacuum possible? And what would

503
00:24:57,040 --> 00:24:59,399
Speaker 1: it look like, like, can you have a chunk of

504
00:24:59,440 --> 00:25:03,000
Speaker 1: space with that any particle, matter or energy in it?

505
00:25:03,200 --> 00:25:04,520
Speaker 1: What's left if you have none of that?

506
00:25:04,880 --> 00:25:07,960
Speaker 2: Yeah, So imagine that you were able to somehow rid

507
00:25:08,000 --> 00:25:10,040
Speaker 2: a chunk of space of all the particles. Maybe you

508
00:25:10,080 --> 00:25:13,639
Speaker 2: built a box that blocked all photons another matter from entering,

509
00:25:13,680 --> 00:25:16,040
Speaker 2: and you sucked everything out of it. What would be

510
00:25:16,200 --> 00:25:18,959
Speaker 2: in there? Right? What is sort of the nature of nothing?

511
00:25:19,040 --> 00:25:22,120
Speaker 2: What is the minimum thing that exists in the universe?

512
00:25:22,240 --> 00:25:24,880
Speaker 2: Or like, what is reality when there's nothing in it?

513
00:25:25,600 --> 00:25:27,399
Speaker 2: And you know, we don't know the answer to that

514
00:25:27,480 --> 00:25:29,919
Speaker 2: question at the deepest level, but we do have a

515
00:25:29,960 --> 00:25:32,840
Speaker 2: theory that describes it. Right. We call that thing space,

516
00:25:32,920 --> 00:25:36,320
Speaker 2: and space still has a structure to it even if

517
00:25:36,359 --> 00:25:38,879
Speaker 2: you suck all the stuff out of it. Right, This

518
00:25:38,920 --> 00:25:40,720
Speaker 2: is what we were talking about earlier, that there's a

519
00:25:40,880 --> 00:25:45,600
Speaker 2: possibility for things to exist, and that possibility are the fields.

520
00:25:45,960 --> 00:25:49,080
Speaker 2: We think of these as part of space itself, That

521
00:25:49,160 --> 00:25:52,480
Speaker 2: these fields exist even when there's nothing in them, that

522
00:25:52,520 --> 00:25:55,320
Speaker 2: the possibility for things to exist is part of the

523
00:25:55,320 --> 00:25:56,960
Speaker 2: structure of space itself.

524
00:25:57,320 --> 00:25:57,560
Speaker 4: Hmm.

525
00:25:57,920 --> 00:25:59,680
Speaker 1: I guess, as you were saying, it kind of depends

526
00:25:59,720 --> 00:26:02,160
Speaker 1: on what that you consider fields to be a thing

527
00:26:02,440 --> 00:26:04,800
Speaker 1: or not. Like, if you consider them to be a thing,

528
00:26:05,040 --> 00:26:07,199
Speaker 1: then fields kind of take up all of space in

529
00:26:07,240 --> 00:26:10,160
Speaker 1: the universe, right, So you can't have a space without fields.

530
00:26:10,200 --> 00:26:13,520
Speaker 1: But if fields are just kind of a made up concept,

531
00:26:13,560 --> 00:26:15,200
Speaker 1: then it is possible to have empty space.

532
00:26:15,440 --> 00:26:17,600
Speaker 2: If you consider field to be the most fundamental, then yes,

533
00:26:17,680 --> 00:26:20,800
Speaker 2: they are the bedrock. They are contained as part of space.

534
00:26:20,840 --> 00:26:23,280
Speaker 2: They're a fundamental aspect of the universe. And we can

535
00:26:23,320 --> 00:26:25,520
Speaker 2: talk in a minute about like what is the lowest

536
00:26:25,640 --> 00:26:28,840
Speaker 2: energy those fields can occupy, what would that vacuum mean, etcetera,

537
00:26:28,880 --> 00:26:31,280
Speaker 2: et cetera. If you reject fields and say, look, I

538
00:26:31,280 --> 00:26:33,880
Speaker 2: can't ever see fields. I don't think that those really

539
00:26:33,920 --> 00:26:36,000
Speaker 2: are the way particles push on each other, then you

540
00:26:36,040 --> 00:26:39,840
Speaker 2: have another picture, which is virtual particles. Particles push on

541
00:26:39,840 --> 00:26:42,399
Speaker 2: each other by exchanging these virtual particles, you know, and

542
00:26:42,480 --> 00:26:45,720
Speaker 2: two electrons whiz by each other. They're not using their

543
00:26:45,720 --> 00:26:48,800
Speaker 2: fields to push on each other. They're exchanging virtual photons.

544
00:26:49,000 --> 00:26:51,040
Speaker 2: So if you use that picture, you don't just delete

545
00:26:51,040 --> 00:26:53,440
Speaker 2: the field to replace it with nothing else. You delete

546
00:26:53,480 --> 00:26:55,600
Speaker 2: the fields and you replace it with an infinite number

547
00:26:55,680 --> 00:26:59,160
Speaker 2: of virtual particles. So in neither picture of the universe

548
00:26:59,200 --> 00:27:02,080
Speaker 2: is really true empty, even when you have no real

549
00:27:02,359 --> 00:27:03,040
Speaker 2: matter in it.

550
00:27:03,960 --> 00:27:07,600
Speaker 1: Well, is it possible to have space without fields? Right?

551
00:27:07,640 --> 00:27:10,720
Speaker 1: Because fields kind of have come and gone in our

552
00:27:10,800 --> 00:27:14,080
Speaker 1: history of the universe, and also I think mathematically it's

553
00:27:14,119 --> 00:27:16,199
Speaker 1: sort of possible to just not have a field and

554
00:27:16,240 --> 00:27:17,200
Speaker 1: still have space. Right.

555
00:27:17,400 --> 00:27:19,119
Speaker 2: What do you mean fields have come and gone? You

556
00:27:19,160 --> 00:27:22,040
Speaker 2: mean it's a scientific concept, or in the cosmological history

557
00:27:22,040 --> 00:27:22,640
Speaker 2: of the universe.

558
00:27:22,800 --> 00:27:25,000
Speaker 1: I mean, like in the cosmological history right, like you know,

559
00:27:25,040 --> 00:27:26,879
Speaker 1: the Big Bang, we didn't have some of the fields

560
00:27:26,880 --> 00:27:27,480
Speaker 1: we have. Right.

561
00:27:27,520 --> 00:27:29,879
Speaker 2: Our description of the history of the universe goes back really,

562
00:27:29,920 --> 00:27:32,200
Speaker 2: really far to what we think is like a few

563
00:27:32,359 --> 00:27:35,840
Speaker 2: tiny moments in time after maybe the universe was created.

564
00:27:35,920 --> 00:27:37,560
Speaker 2: But it really goes back only as far as we

565
00:27:37,600 --> 00:27:40,400
Speaker 2: can describe with our current laws of physics, and those

566
00:27:40,480 --> 00:27:43,520
Speaker 2: laws always include fields. So it might be that before

567
00:27:43,520 --> 00:27:45,960
Speaker 2: a certain point there weren't fields, But that's because the

568
00:27:46,040 --> 00:27:48,360
Speaker 2: universe is like in a different phase where fields are

569
00:27:48,359 --> 00:27:51,679
Speaker 2: no longer a good description of what's happening, and so

570
00:27:51,720 --> 00:27:54,160
Speaker 2: we use fields as a way to describe the universe

571
00:27:54,200 --> 00:27:57,360
Speaker 2: we're in right now, we don't know if fields are

572
00:27:57,400 --> 00:28:00,960
Speaker 2: fundamental or when the universe changes conditions to a point

573
00:28:00,960 --> 00:28:03,240
Speaker 2: where these laws of physics are no longer relevant that

574
00:28:03,320 --> 00:28:07,240
Speaker 2: some other description is useful. Going back to your fish analogy,

575
00:28:07,359 --> 00:28:10,199
Speaker 2: sort of imagining that the universe currently is in a

576
00:28:10,240 --> 00:28:13,600
Speaker 2: certain phase, like the way the fish are swimming through water,

577
00:28:13,640 --> 00:28:15,719
Speaker 2: and that water is a certain phase, and they develop

578
00:28:15,840 --> 00:28:18,919
Speaker 2: laws of physics that describe, you know, the fluid dynamics

579
00:28:18,920 --> 00:28:21,440
Speaker 2: of that water. If the water was to boil, then

580
00:28:21,480 --> 00:28:23,520
Speaker 2: the water's in a new phase and their laws don't

581
00:28:23,520 --> 00:28:26,439
Speaker 2: work anymore. In the same way, there's a moment before

582
00:28:26,560 --> 00:28:30,560
Speaker 2: which we don't think fields probably describe the phase of

583
00:28:30,640 --> 00:28:33,280
Speaker 2: the universe. We don't know how to describe it requires

584
00:28:33,359 --> 00:28:36,840
Speaker 2: quantum gravity. But from that moment and forward, we think

585
00:28:36,920 --> 00:28:40,080
Speaker 2: fields are a good description of the whole universe. So

586
00:28:40,240 --> 00:28:43,040
Speaker 2: in that sense, yeah, fields haven't always existed, but only

587
00:28:43,080 --> 00:28:46,080
Speaker 2: because this phase of the universe hasn't always existed.

588
00:28:47,160 --> 00:28:48,640
Speaker 1: Well, I guess what I mean is like, if it

589
00:28:48,720 --> 00:28:52,240
Speaker 1: is a phase, it kind of seems optional, kind of

590
00:28:52,240 --> 00:28:54,840
Speaker 1: like the water in the ocean, right, Like, you know,

591
00:28:54,880 --> 00:28:58,440
Speaker 1: you can imagine a universe existing without the muon field

592
00:28:58,640 --> 00:29:01,600
Speaker 1: for example, it's out field or the you know, certain

593
00:29:01,680 --> 00:29:04,200
Speaker 1: quarks or whatever, and you would still maybe have a

594
00:29:04,200 --> 00:29:07,240
Speaker 1: functioning universe, which means maybe they're optional, in which case

595
00:29:07,280 --> 00:29:09,320
Speaker 1: maybe you can have a universe without fields.

596
00:29:09,400 --> 00:29:11,520
Speaker 2: We don't know the answer to that question, right, What

597
00:29:11,680 --> 00:29:15,040
Speaker 2: is the physics of other phases of the universe where

598
00:29:15,080 --> 00:29:17,560
Speaker 2: our laws of physics do not apply. That's a question

599
00:29:17,640 --> 00:29:20,640
Speaker 2: of like what is quantum gravity? You know what happens

600
00:29:20,680 --> 00:29:23,680
Speaker 2: when things get super duper dense and very very hot,

601
00:29:23,960 --> 00:29:26,920
Speaker 2: where gravity is important and quantum mechanics is important. We

602
00:29:27,040 --> 00:29:29,520
Speaker 2: just don't have a theory that describes that. Some candidate

603
00:29:29,560 --> 00:29:32,560
Speaker 2: theories do include fields, right, There's still are fields in

604
00:29:32,640 --> 00:29:34,920
Speaker 2: some of those theories, and so it might be that

605
00:29:34,920 --> 00:29:37,480
Speaker 2: there are still fields back before that moment in time

606
00:29:37,520 --> 00:29:40,600
Speaker 2: when our current theories break down. We just don't know.

607
00:29:41,160 --> 00:29:43,360
Speaker 2: So from that point of view, you don't always have fields.

608
00:29:43,440 --> 00:29:45,560
Speaker 2: But if we're talking about, like what is a vacuum,

609
00:29:46,000 --> 00:29:48,000
Speaker 2: I think that's sort of in the context of our

610
00:29:48,120 --> 00:29:51,560
Speaker 2: current kind of space, the current phase of the universe

611
00:29:51,600 --> 00:29:53,840
Speaker 2: that we're in. You can still say what is a

612
00:29:53,920 --> 00:29:55,920
Speaker 2: vacuum in that context.

613
00:29:55,880 --> 00:29:57,800
Speaker 1: So then I'm trying to figure out what you're trying

614
00:29:57,800 --> 00:30:00,400
Speaker 1: to say. Are you saying that you can not have

615
00:30:00,480 --> 00:30:03,040
Speaker 1: a vacuum a true vacuum. Or are you saying that

616
00:30:03,280 --> 00:30:05,680
Speaker 1: you can't have a vacuum where there's not even fields

617
00:30:05,720 --> 00:30:08,360
Speaker 1: in it, or does your definition of a vacuum just

618
00:30:08,400 --> 00:30:12,200
Speaker 1: includes the fields as a base kind of layer of existence.

619
00:30:12,360 --> 00:30:14,880
Speaker 2: It's that last one. What we consider a vacuum is

620
00:30:15,040 --> 00:30:18,480
Speaker 2: space at its most relaxed, which is what is the

621
00:30:18,640 --> 00:30:22,840
Speaker 2: least energy possible to exist in space. And because our

622
00:30:22,920 --> 00:30:25,880
Speaker 2: concept of space includes these built in fields, they will

623
00:30:25,880 --> 00:30:30,200
Speaker 2: always contain fields. So a vacuum is not perfect zeroness,

624
00:30:30,560 --> 00:30:33,560
Speaker 2: complete emptiness. It's a most relaxed state of space which

625
00:30:33,600 --> 00:30:35,440
Speaker 2: will always include these fields.

626
00:30:36,080 --> 00:30:39,440
Speaker 1: M But I guess, is it theoretically possible to have

627
00:30:39,600 --> 00:30:41,440
Speaker 1: zero energy space?

628
00:30:41,840 --> 00:30:44,840
Speaker 2: It is not theoretically possible because all these fields are

629
00:30:45,000 --> 00:30:49,200
Speaker 2: quantum fields. They're not classical fields like Maxwell's theory of electromagnetism,

630
00:30:49,200 --> 00:30:52,680
Speaker 2: which has like electric and magnetic fields oscillating which makes light.

631
00:30:52,800 --> 00:30:55,280
Speaker 2: Those fields could be absolute zero. You could have them

632
00:30:55,280 --> 00:30:57,720
Speaker 2: at zero energy. You could have zero electric field and

633
00:30:57,800 --> 00:31:00,920
Speaker 2: zero magnetic field. Our modern view is that these fields

634
00:31:00,920 --> 00:31:04,520
Speaker 2: are quantum fields, which means they oscillate differently instead of

635
00:31:04,560 --> 00:31:07,120
Speaker 2: whiggling like a string, where they can take any value.

636
00:31:07,400 --> 00:31:10,680
Speaker 2: There are only certain solutions that are allowed, they're like discretized,

637
00:31:10,720 --> 00:31:14,640
Speaker 2: they're quantized, and the mathematics don't work for zero energy,

638
00:31:15,040 --> 00:31:18,560
Speaker 2: Like the solution of the quantum field equations don't allow

639
00:31:18,600 --> 00:31:22,120
Speaker 2: a zero energy solutions. It's like a minimum energy required

640
00:31:22,480 --> 00:31:25,480
Speaker 2: for any quantum fields. They have to be like bubbling

641
00:31:25,520 --> 00:31:30,120
Speaker 2: and frothing at some tiny little level, at the very minimum.

642
00:31:30,120 --> 00:31:31,920
Speaker 1: I guess maybe what I'm asking it at a fundamental

643
00:31:32,000 --> 00:31:34,680
Speaker 1: level is can you have a universe with no fields?

644
00:31:34,840 --> 00:31:36,960
Speaker 2: Are you asking whether we could have a universe with

645
00:31:37,120 --> 00:31:40,200
Speaker 2: fields that are at zero or a universe where space

646
00:31:40,520 --> 00:31:43,240
Speaker 2: literally does not have the capacity for fields.

647
00:31:43,440 --> 00:31:45,840
Speaker 1: Can you have a universe where there are no fields

648
00:31:45,880 --> 00:31:46,160
Speaker 1: in it?

649
00:31:46,480 --> 00:31:49,200
Speaker 2: That? We don't know? Right? Our current definition of space

650
00:31:49,560 --> 00:31:52,640
Speaker 2: has these fields built in. Is it possible to have

651
00:31:52,680 --> 00:31:55,440
Speaker 2: another kind of space without fields, where you wouldn't even

652
00:31:55,520 --> 00:31:58,080
Speaker 2: have the possibility to have matter in it? We don't know.

653
00:31:58,120 --> 00:31:59,880
Speaker 2: We don't even know what that would mean, right, because

654
00:31:59,880 --> 00:32:02,360
Speaker 2: you can't have things in it. What does distance really mean?

655
00:32:02,400 --> 00:32:05,000
Speaker 2: If space is by definition empty, distance is sort of

656
00:32:05,040 --> 00:32:08,200
Speaker 2: defined to be between two locations, right, So that would

657
00:32:08,200 --> 00:32:10,840
Speaker 2: be like a whole new kind of space, one that

658
00:32:10,840 --> 00:32:13,320
Speaker 2: doesn't even have the capacity to have stuff in it.

659
00:32:13,840 --> 00:32:16,080
Speaker 1: But that does a math allow for it, or does

660
00:32:16,160 --> 00:32:18,840
Speaker 1: a math not only exist, like the math we have

661
00:32:19,080 --> 00:32:23,640
Speaker 1: only exists or is defined in a universe with fields

662
00:32:23,640 --> 00:32:23,920
Speaker 1: in it.

663
00:32:24,280 --> 00:32:27,160
Speaker 2: You could create a conceptual space with no fields in it.

664
00:32:27,200 --> 00:32:30,040
Speaker 2: Sure it's trivial, right, Like, there's no math for it,

665
00:32:30,160 --> 00:32:33,040
Speaker 2: there's nothing in it. Right, So it's just like it's

666
00:32:33,040 --> 00:32:35,280
Speaker 2: like writing nothing on a sheet of paper. That's your theory.

667
00:32:38,680 --> 00:32:42,160
Speaker 1: Well, yeah, I mean kind of right. Well there's a paper, right,

668
00:32:42,280 --> 00:32:44,880
Speaker 1: the paper exists, you're just not putting an equation in it,

669
00:32:45,400 --> 00:32:46,720
Speaker 1: or you're writing zero in it.

670
00:32:46,800 --> 00:32:49,560
Speaker 2: Yeah, zero, right? But what is zero like is that

671
00:32:49,640 --> 00:32:51,760
Speaker 2: you have a field whose value is zero? If you're

672
00:32:51,760 --> 00:32:55,360
Speaker 2: talking about like really true empty of any theoretical content

673
00:32:55,520 --> 00:32:59,480
Speaker 2: that can exist. Theoretically, it doesn't describe anything in our universe. Right,

674
00:32:59,760 --> 00:33:02,720
Speaker 2: All these concept have to make contact with reality. So

675
00:33:02,840 --> 00:33:05,520
Speaker 2: our best description of reality as we see it out

676
00:33:05,560 --> 00:33:07,760
Speaker 2: there is space that always has fields in it, and

677
00:33:07,800 --> 00:33:11,400
Speaker 2: those fields are never at zero energy. We've never discovered

678
00:33:11,440 --> 00:33:16,120
Speaker 2: any evidence for fieldless space. Theoretically you can make that concept, sure,

679
00:33:16,560 --> 00:33:18,160
Speaker 2: but we don't think it describes reality.

680
00:33:18,720 --> 00:33:20,240
Speaker 1: I see. So I think what you're saying is that

681
00:33:20,280 --> 00:33:23,600
Speaker 1: the universe that we see out there has fields in it,

682
00:33:24,240 --> 00:33:27,320
Speaker 1: and therefore there's no such thing as perfect nothingness because

683
00:33:27,400 --> 00:33:28,840
Speaker 1: everything we see has fields in it.

684
00:33:28,960 --> 00:33:31,680
Speaker 2: Yeah, if perfect nothingness as things without fields, then we

685
00:33:31,720 --> 00:33:34,320
Speaker 2: don't think that exists. In the universe. Every chunk of

686
00:33:34,400 --> 00:33:37,960
Speaker 2: space has those fields, and those fields have some zero

687
00:33:38,120 --> 00:33:43,000
Speaker 2: point energy, some minimum fuzziness, some oscillation to them. For example,

688
00:33:43,040 --> 00:33:45,240
Speaker 2: the Higgs field feels all of space, and the Higgs

689
00:33:45,240 --> 00:33:48,520
Speaker 2: field is sort of weirdly stuck at high energy, so

690
00:33:48,520 --> 00:33:51,160
Speaker 2: it's not a trivial amount of energy that's in space

691
00:33:51,480 --> 00:33:52,840
Speaker 2: even when there's no matter in it.

692
00:33:53,440 --> 00:33:55,800
Speaker 1: But I think what you mean by like everywhere there

693
00:33:55,840 --> 00:33:58,160
Speaker 1: has this little bit of energy to it, you don't

694
00:33:58,200 --> 00:34:00,880
Speaker 1: mean like there's actually energy there. I think what you

695
00:34:00,920 --> 00:34:03,640
Speaker 1: mean is that there's kind of like the potential for

696
00:34:03,720 --> 00:34:06,480
Speaker 1: there to be things in it, or like the universe

697
00:34:06,840 --> 00:34:10,520
Speaker 1: leans towards stuff being there.

698
00:34:10,640 --> 00:34:13,919
Speaker 2: No, I mean there's literally energy in space. The Higgs field,

699
00:34:14,000 --> 00:34:17,880
Speaker 2: for example, filled space, and it has a high potential energy.

700
00:34:17,960 --> 00:34:20,280
Speaker 2: Even if there are no particles there. There is energy

701
00:34:20,320 --> 00:34:22,680
Speaker 2: in the configuration of the field itself.

702
00:34:22,760 --> 00:34:24,680
Speaker 1: That's what I mean. I think you said it has

703
00:34:24,680 --> 00:34:27,759
Speaker 1: the potential to do stuff it's a potential energy. It's

704
00:34:27,800 --> 00:34:29,760
Speaker 1: not like a little photon floating out there in space.

705
00:34:29,800 --> 00:34:32,560
Speaker 2: That's right, it's potential energy exactly. It's like if you

706
00:34:32,600 --> 00:34:35,040
Speaker 2: mentioned a guitar string. Somebody has pulled the guitar string

707
00:34:35,080 --> 00:34:37,279
Speaker 2: away from its relaxed state and it's taught, so it's

708
00:34:37,280 --> 00:34:40,040
Speaker 2: storing energy in that. It's not moving. There's no kinetic

709
00:34:40,239 --> 00:34:43,040
Speaker 2: energy right now. It's not oscillating, but it's held in

710
00:34:43,080 --> 00:34:46,120
Speaker 2: a configuration that has energy. If somebody was to release it,

711
00:34:46,120 --> 00:34:48,680
Speaker 2: it would vibrate and make a noise. Right. The Higgs

712
00:34:48,719 --> 00:34:51,360
Speaker 2: field is just like that. It's held in some configuration

713
00:34:51,440 --> 00:34:54,680
Speaker 2: that stores a lot of energy, and that's potential energy.

714
00:34:54,800 --> 00:34:57,239
Speaker 2: But every field has some energy in it, not even

715
00:34:57,320 --> 00:34:59,800
Speaker 2: just the Higgs field, Like the electromagnetic field that feels

716
00:34:59,800 --> 00:35:02,560
Speaker 2: space is held in a non zero value and that's

717
00:35:02,600 --> 00:35:06,640
Speaker 2: not just potential energy. That's like actually thrumming with kinetic energy.

718
00:35:06,760 --> 00:35:08,839
Speaker 1: Thruw I mean in a quantum says that. I think

719
00:35:08,960 --> 00:35:11,840
Speaker 1: what you mean is like there's like quantum particles popping

720
00:35:11,880 --> 00:35:13,399
Speaker 1: in and out of existence. Is that what you mean?

721
00:35:13,719 --> 00:35:16,359
Speaker 2: Not enough energy to make a real particle, But the

722
00:35:16,400 --> 00:35:19,440
Speaker 2: field itself has energy. It is vibrating. You can think

723
00:35:19,440 --> 00:35:22,480
Speaker 2: of these fields as having kinetic energy and potential energy,

724
00:35:22,680 --> 00:35:24,959
Speaker 2: just like a string, right, which slides back and forth

725
00:35:25,000 --> 00:35:27,960
Speaker 2: between having kinetic and potential energy as it oscillates. So

726
00:35:28,000 --> 00:35:32,080
Speaker 2: these fields have actual energy, not enough to make a particle. Right,

727
00:35:32,120 --> 00:35:35,200
Speaker 2: The lowest energy state of these things is not one particle.

728
00:35:35,239 --> 00:35:38,359
Speaker 2: It's zero particles, but not zero energy.

729
00:35:38,320 --> 00:35:39,719
Speaker 1: All right, So then what does that mean for the

730
00:35:39,760 --> 00:35:42,200
Speaker 1: idea of a vacuum. Means that in our universe you

731
00:35:42,360 --> 00:35:43,840
Speaker 1: can have a perfect vacuum.

732
00:35:43,960 --> 00:35:47,560
Speaker 2: In our universe, we define sort of theoretical concept is

733
00:35:47,840 --> 00:35:51,040
Speaker 2: the most relaxed state of all the fields. That's sort

734
00:35:51,040 --> 00:35:53,400
Speaker 2: of like how we define a vacuum. We don't define

735
00:35:53,400 --> 00:35:55,480
Speaker 2: it to be like the theoretical minimum where all the

736
00:35:55,480 --> 00:35:58,560
Speaker 2: fields are a zero, because that's not theoretically possible. We

737
00:35:58,640 --> 00:36:01,240
Speaker 2: consider this sort of state of space as we understand

738
00:36:01,320 --> 00:36:03,279
Speaker 2: it and try to imagine what would be the most

739
00:36:03,400 --> 00:36:07,319
Speaker 2: relaxed configuration that all the field could get into. And

740
00:36:07,400 --> 00:36:09,960
Speaker 2: we now know that that's not at zero. But what's

741
00:36:10,000 --> 00:36:13,160
Speaker 2: interesting is that there might be multiple ways for the

742
00:36:13,200 --> 00:36:16,480
Speaker 2: field to relax. There might be a few stable configurations.

743
00:36:16,880 --> 00:36:19,120
Speaker 2: One of those would be the true vacuum. The actual

744
00:36:19,280 --> 00:36:22,920
Speaker 2: lowest possible state. The other ones would be false vacua

745
00:36:23,080 --> 00:36:25,880
Speaker 2: like places that space gets stuck as it's trying to

746
00:36:25,920 --> 00:36:27,920
Speaker 2: relax down to zero and it ends up in a

747
00:36:28,000 --> 00:36:31,560
Speaker 2: stable configuration that's not actually the lowest energy state.

748
00:36:31,800 --> 00:36:33,399
Speaker 1: I think what you're saying is that, like even if

749
00:36:33,400 --> 00:36:34,960
Speaker 1: you go out there in the middle of space, or

750
00:36:34,960 --> 00:36:37,320
Speaker 1: even if you create one, like you make a box

751
00:36:37,640 --> 00:36:40,400
Speaker 1: where nothing can get in it and there's no particles,

752
00:36:40,440 --> 00:36:43,160
Speaker 1: you see, no particles in it, there is still a

753
00:36:43,160 --> 00:36:45,320
Speaker 1: little bit of like thrumbing or a little bit of

754
00:36:45,600 --> 00:36:50,880
Speaker 1: vibration of the fields in that space not creating fully particles,

755
00:36:50,880 --> 00:36:53,000
Speaker 1: Like there's not enough there to actually pop out a

756
00:36:53,040 --> 00:36:55,520
Speaker 1: particle with that you can see and interact with. But

757
00:36:55,680 --> 00:36:58,640
Speaker 1: there's like, you know, half a particle forming and then

758
00:36:58,680 --> 00:37:01,799
Speaker 1: it's gone. There's a quarter of a particle Thereah, but

759
00:37:01,920 --> 00:37:03,720
Speaker 1: it's gone. Kind of situation, right.

760
00:37:03,600 --> 00:37:05,760
Speaker 2: Yeah, And you just intuited your way from the field

761
00:37:05,760 --> 00:37:08,319
Speaker 2: description to the particles cold description, Like what does the

762
00:37:08,440 --> 00:37:10,640
Speaker 2: energy of this field mean if it's not enough to

763
00:37:10,680 --> 00:37:13,319
Speaker 2: have an actual particle there. Well, it's sort of like

764
00:37:13,520 --> 00:37:15,440
Speaker 2: you know the particles exist, and that they don't they

765
00:37:15,440 --> 00:37:18,400
Speaker 2: pop in and out of existence. That's replacing the idea

766
00:37:18,440 --> 00:37:21,080
Speaker 2: of a field with these virtual particles that have some

767
00:37:21,160 --> 00:37:24,320
Speaker 2: weird energy from space itself and not enough to really

768
00:37:24,360 --> 00:37:26,160
Speaker 2: exist in the sense of like it could hang out

769
00:37:26,239 --> 00:37:28,279
Speaker 2: and you could leave the electron there and come back

770
00:37:28,320 --> 00:37:30,600
Speaker 2: a billion years later it would still be there. These

771
00:37:30,640 --> 00:37:33,279
Speaker 2: are virtual particles. That's sort of intuitive way to think

772
00:37:33,320 --> 00:37:35,879
Speaker 2: about what a virtual particle is, just like another way

773
00:37:35,920 --> 00:37:37,960
Speaker 2: to think about a field. When the field doesn't have

774
00:37:38,040 --> 00:37:40,359
Speaker 2: enough energy to make real particles, it might have enough

775
00:37:40,400 --> 00:37:41,800
Speaker 2: to make virtual particles.

776
00:37:42,000 --> 00:37:44,719
Speaker 1: All right, well, let's get into the idea of what

777
00:37:44,760 --> 00:37:47,680
Speaker 1: it would mean if you actually created a real vacuum,

778
00:37:47,880 --> 00:37:49,880
Speaker 1: and it has to do with this concept of a

779
00:37:50,080 --> 00:37:52,800
Speaker 1: fields relaxing. How relax can you make a field? What

780
00:37:52,920 --> 00:37:54,879
Speaker 1: sort of medication you need to give it in order

781
00:37:54,920 --> 00:37:57,759
Speaker 1: for it to finally relax. We'll dig into that, but

782
00:37:57,800 --> 00:38:13,120
Speaker 1: first let's take another quick break. All right, we're talking

783
00:38:13,120 --> 00:38:16,040
Speaker 1: about nothing today. This is the episode about nothing.

784
00:38:16,200 --> 00:38:17,800
Speaker 2: This is the Seinfeld of podcast.

785
00:38:18,600 --> 00:38:22,080
Speaker 1: That's right. I'll be Kramer and you be Which one

786
00:38:22,120 --> 00:38:24,839
Speaker 1: of us is Kramer, Which one of them is George? Consensus.

787
00:38:24,840 --> 00:38:26,960
Speaker 2: I think you're definitely more Kramer and I'm more George.

788
00:38:26,960 --> 00:38:30,240
Speaker 2: For sure. I always wanted to be an architect.

789
00:38:31,280 --> 00:38:34,080
Speaker 1: Yeah, I thought I was a comedian. Wait a minute,

790
00:38:34,280 --> 00:38:36,359
Speaker 1: but we were talking about nothing and the idea of

791
00:38:36,400 --> 00:38:39,360
Speaker 1: nothing and whether it's possible to have nothing in the universe,

792
00:38:39,400 --> 00:38:42,279
Speaker 1: and it sounds like that's not really possible. In the

793
00:38:42,360 --> 00:38:46,200
Speaker 1: universe that we see and experience, there are things called

794
00:38:46,280 --> 00:38:49,880
Speaker 1: quantum fields and so you which occupied all of space

795
00:38:50,000 --> 00:38:53,360
Speaker 1: and which has kind of inherent energy to it. So

796
00:38:53,400 --> 00:38:56,600
Speaker 1: there's really no trunk of space out there that has

797
00:38:56,719 --> 00:38:57,360
Speaker 1: zero energy.

798
00:38:57,760 --> 00:39:00,760
Speaker 2: Yeah, that's right. Space has these fields and they're always

799
00:39:00,800 --> 00:39:03,520
Speaker 2: wiggling at least a little bit. And so instead of

800
00:39:03,600 --> 00:39:07,560
Speaker 2: thinking about true zeroness of space, which we think is impossible,

801
00:39:07,640 --> 00:39:11,280
Speaker 2: physicists like to think about the minimum energy state of space.

802
00:39:11,320 --> 00:39:13,960
Speaker 2: That's what we call the vacuum, what happens when space

803
00:39:14,000 --> 00:39:16,720
Speaker 2: relaxes as much as it's theoretically allowed.

804
00:39:17,000 --> 00:39:19,600
Speaker 1: Okay, so then I guess we're this more like maximum

805
00:39:19,680 --> 00:39:22,960
Speaker 1: vacuum of the universe. Maybe not the perfect vacuum, but

806
00:39:23,000 --> 00:39:25,960
Speaker 1: the most vacuuminess that the universe can get.

807
00:39:26,160 --> 00:39:29,360
Speaker 2: Yeah, the vacuumiist. But I like that phrase maximum vacuum.

808
00:39:29,360 --> 00:39:33,840
Speaker 2: That sounds cool like an eighties band starring Max headroom.

809
00:39:34,280 --> 00:39:37,839
Speaker 1: Yeah with long long hair, Yeah, that might be out

810
00:39:37,880 --> 00:39:39,040
Speaker 1: of our reach at our age.

811
00:39:39,200 --> 00:39:43,000
Speaker 2: And to understand what's actually achievable, like how you can

812
00:39:43,080 --> 00:39:46,120
Speaker 2: really relax space itself, you have to understand like how

813
00:39:46,160 --> 00:39:48,319
Speaker 2: the fields wiggle and how they interact with each other,

814
00:39:48,360 --> 00:39:51,239
Speaker 2: how energy slashes back and forth. It's sort of like

815
00:39:51,280 --> 00:39:52,880
Speaker 2: you know when you lie down to take a nap

816
00:39:52,920 --> 00:39:55,960
Speaker 2: and you feel like, okay, I'm totally relaxed. Then you discover,

817
00:39:56,239 --> 00:39:58,960
Speaker 2: oh no, I'm actually holding this muscle tot and you

818
00:39:59,120 --> 00:40:01,480
Speaker 2: learn to relax that, to relax that, and you only

819
00:40:01,520 --> 00:40:03,680
Speaker 2: really ever fall asleep when all of your muscles are

820
00:40:03,719 --> 00:40:06,359
Speaker 2: fully relaxed in their lowest energy state.

821
00:40:06,760 --> 00:40:09,040
Speaker 1: Well, I guess maybe a question is there are fields

822
00:40:09,080 --> 00:40:11,520
Speaker 1: that have zero energy to them or not? Or do

823
00:40:11,640 --> 00:40:14,439
Speaker 1: all quantum fields have some inherent energy to them?

824
00:40:14,560 --> 00:40:17,080
Speaker 2: No quantum fields can have zero energy in them. It's

825
00:40:17,120 --> 00:40:21,160
Speaker 2: just an inherent property of any quantum object that cannot

826
00:40:21,200 --> 00:40:22,360
Speaker 2: have zero energy.

827
00:40:22,440 --> 00:40:22,759
Speaker 1: Why not.

828
00:40:23,040 --> 00:40:25,600
Speaker 2: There's the mathematical approach, which is like you look at

829
00:40:25,640 --> 00:40:27,960
Speaker 2: the shorter your equation, you try to solve it. The

830
00:40:28,000 --> 00:40:31,480
Speaker 2: minimum energy solution is not at zero. The intuitive way

831
00:40:31,480 --> 00:40:34,080
Speaker 2: to think about it is the heisember concertainty principle. Right,

832
00:40:34,120 --> 00:40:37,879
Speaker 2: If you accept that things have a minimum uncertainty to them,

833
00:40:38,120 --> 00:40:41,879
Speaker 2: then having zero energy would perfectly define its momentum and

834
00:40:41,960 --> 00:40:44,560
Speaker 2: its location. At the same time, you would know too

835
00:40:44,640 --> 00:40:47,839
Speaker 2: much about it. So in order to maintain the fuzziness

836
00:40:47,840 --> 00:40:50,360
Speaker 2: of the universe, these quantum fields have to be buzzing

837
00:40:50,440 --> 00:40:51,000
Speaker 2: a little bit.

838
00:40:51,440 --> 00:40:55,240
Speaker 1: WHOA that seems to get really philosophical.

839
00:40:54,760 --> 00:40:57,560
Speaker 2: Every time you try to understand quantum mechanics intuitively, you

840
00:40:57,680 --> 00:41:00,439
Speaker 2: got to reach for philosophy. That's really all we have.

841
00:41:00,960 --> 00:41:03,600
Speaker 2: You know, quantum mechanics has the beautiful mathematics which gives

842
00:41:03,640 --> 00:41:07,080
Speaker 2: you answers. But you want like intuitive understanding, then it's

843
00:41:07,120 --> 00:41:07,960
Speaker 2: all philosophy.

844
00:41:08,239 --> 00:41:10,040
Speaker 1: But what do you mean, Like you can't have uncertainty

845
00:41:10,200 --> 00:41:12,800
Speaker 1: with a perfect vacuum? Like could you have a field

846
00:41:12,840 --> 00:41:15,759
Speaker 1: that has zero average energy but it kind of like

847
00:41:16,160 --> 00:41:18,600
Speaker 1: has a negative state of being. I don't know, I

848
00:41:18,640 --> 00:41:20,360
Speaker 1: don't know what I'm talking about, But why can't you

849
00:41:20,400 --> 00:41:23,400
Speaker 1: have fuzziness and a zero average.

850
00:41:23,120 --> 00:41:26,759
Speaker 2: The value of the field is zero on average, but

851
00:41:26,880 --> 00:41:29,239
Speaker 2: the energy is not zero the same way that like

852
00:41:29,280 --> 00:41:31,839
Speaker 2: when a string vibrates on the guitar. If you took

853
00:41:31,960 --> 00:41:34,640
Speaker 2: pictures of where the string was and you average it's location.

854
00:41:34,760 --> 00:41:38,360
Speaker 2: Its average location is at the most relaxed state, or

855
00:41:38,360 --> 00:41:40,960
Speaker 2: at a straight string. You took any point on that

856
00:41:41,000 --> 00:41:43,840
Speaker 2: string and asks like, where is it on average? On average,

857
00:41:43,880 --> 00:41:45,960
Speaker 2: it's at its relaxed state. It's at the middle point

858
00:41:46,000 --> 00:41:48,879
Speaker 2: where the string is straight. But it's oscillating still, right,

859
00:41:49,120 --> 00:41:52,080
Speaker 2: it's still moving. So these fields can have energy while

860
00:41:52,120 --> 00:41:54,000
Speaker 2: their average value is still at zero.

861
00:41:54,280 --> 00:41:57,160
Speaker 1: And so what would happen if a string had no energy.

862
00:41:56,880 --> 00:41:59,160
Speaker 2: Well, a classical string can have no energy, right, And

863
00:41:59,200 --> 00:42:02,600
Speaker 2: that means you know exactly its location and exactly it's momentum.

864
00:42:02,760 --> 00:42:06,000
Speaker 2: It's zero momentum. But a quantum object can't do that.

865
00:42:06,120 --> 00:42:08,880
Speaker 2: You can't know both of those things simultaneously about a

866
00:42:08,960 --> 00:42:11,319
Speaker 2: quantum object. And it's not just that we can't know it.

867
00:42:11,360 --> 00:42:15,920
Speaker 2: Then information does not exist, cannot exist. It's not Noah bowl,

868
00:42:16,480 --> 00:42:18,480
Speaker 2: it's not determined.

869
00:42:17,880 --> 00:42:19,520
Speaker 1: Which wouldn't be a quantum object.

870
00:42:19,640 --> 00:42:22,320
Speaker 2: Oh yeah, sure, if you want to overthrow quantum mechanics,

871
00:42:22,320 --> 00:42:25,480
Speaker 2: then yes, you can have objects with zero energy. So

872
00:42:25,600 --> 00:42:29,040
Speaker 2: classical fields definitely can. But all evidence suggests that all

873
00:42:29,040 --> 00:42:32,040
Speaker 2: the fields we know about other than gravity at least

874
00:42:32,480 --> 00:42:34,840
Speaker 2: are quantum fields. They have quantum properties.

875
00:42:34,960 --> 00:42:37,880
Speaker 1: Wait, are you saying gravity is a non quantum field.

876
00:42:38,000 --> 00:42:40,520
Speaker 2: Well, our theory of gravity is a classical one, right,

877
00:42:40,680 --> 00:42:43,839
Speaker 2: and suggests that space can have zero curvature to it

878
00:42:44,200 --> 00:42:46,520
Speaker 2: and all sorts of stuff. We don't have a quantum

879
00:42:46,560 --> 00:42:49,400
Speaker 2: theory of gravity, so yeah, we have an only classical

880
00:42:49,480 --> 00:42:53,200
Speaker 2: understanding of gravity. We're not successfully quantized gravity. We don't

881
00:42:53,200 --> 00:42:55,120
Speaker 2: even know if gravity is a field or if it's

882
00:42:55,160 --> 00:42:57,479
Speaker 2: just like the curvature of space. So that's not something

883
00:42:57,600 --> 00:42:59,920
Speaker 2: we understand at all. But all the fields that we

884
00:42:59,920 --> 00:43:03,160
Speaker 2: have been able to probe and understand, electromagnetism and the

885
00:43:03,160 --> 00:43:05,960
Speaker 2: weak force, a strong force, these are definitely all quantum

886
00:43:06,000 --> 00:43:08,839
Speaker 2: fields and so they definitely cannot have zero energy. Same

887
00:43:08,880 --> 00:43:11,560
Speaker 2: with the Higgs field, also definitely a quantum field.

888
00:43:11,960 --> 00:43:13,960
Speaker 1: So wait, then, are you saying that if gravity is

889
00:43:14,000 --> 00:43:16,719
Speaker 1: not a quantum field, then you can have a non

890
00:43:16,800 --> 00:43:17,560
Speaker 1: quantum field.

891
00:43:17,800 --> 00:43:20,799
Speaker 2: It's possible that gravity is a non quantum field. Yeah,

892
00:43:20,840 --> 00:43:23,880
Speaker 2: we just don't really understand gravity. I remember that Einstein's

893
00:43:23,880 --> 00:43:26,640
Speaker 2: theory of gravity was developed basically at the same time

894
00:43:26,719 --> 00:43:28,840
Speaker 2: as quantum mechanics, and so he wrote it as a

895
00:43:28,920 --> 00:43:32,520
Speaker 2: classical theory. It makes all sorts of assumptions about the universe.

896
00:43:32,760 --> 00:43:35,359
Speaker 2: You know that you can have smooth, continuous paths that

897
00:43:35,400 --> 00:43:38,520
Speaker 2: you can know precisely the velocity and location of objects,

898
00:43:38,520 --> 00:43:40,360
Speaker 2: things that we don't think are true about the universe.

899
00:43:40,600 --> 00:43:43,240
Speaker 2: He built those into his theory, and yet it works

900
00:43:43,440 --> 00:43:46,399
Speaker 2: in every location where we can test it. So it's

901
00:43:46,400 --> 00:43:49,080
Speaker 2: a deep question in modern physics, like how do we

902
00:43:49,120 --> 00:43:52,440
Speaker 2: reconcile general relativity with quantum mechanics. But yeah, it's possible

903
00:43:52,520 --> 00:43:56,160
Speaker 2: that gravity is a field that's a classical field that

904
00:43:56,239 --> 00:43:57,680
Speaker 2: could relax down to zero.

905
00:43:57,880 --> 00:43:59,400
Speaker 1: I'm just trying to dig into what you say. I

906
00:43:59,400 --> 00:44:01,880
Speaker 1: mean when you say it's not possible, what you actually

907
00:44:01,960 --> 00:44:05,800
Speaker 1: mean is like it's not allowed under or the quantum

908
00:44:05,840 --> 00:44:08,200
Speaker 1: view of the universe, which may or may not be true.

909
00:44:08,320 --> 00:44:11,200
Speaker 2: Yeah, that's true. It might be that the final unification

910
00:44:11,440 --> 00:44:15,200
Speaker 2: and understanding of the bigger picture of physics involves an

911
00:44:15,200 --> 00:44:18,719
Speaker 2: overthrowing of quantum mechanics rather than general relativity. Maybe generativity

912
00:44:18,760 --> 00:44:21,799
Speaker 2: is right, and space is a classical backdrop in some way,

913
00:44:22,040 --> 00:44:25,000
Speaker 2: but in our current understanding of space at least it

914
00:44:25,000 --> 00:44:27,960
Speaker 2: contains these quantum fields which can't go down to zero.

915
00:44:28,280 --> 00:44:29,920
Speaker 2: But yeah, that could be all wrong.

916
00:44:30,160 --> 00:44:33,840
Speaker 1: Okay, Well, let's get back to our discussion vacuums. So

917
00:44:33,840 --> 00:44:36,480
Speaker 1: you're saying that maybe what we can talk about is

918
00:44:36,600 --> 00:44:39,480
Speaker 1: maximum vacuum of the universe, which is when these fields

919
00:44:39,520 --> 00:44:42,680
Speaker 1: relax down to the lowest level. And you're saying that

920
00:44:42,719 --> 00:44:45,760
Speaker 1: there's kind of different ways for these fields to relax,

921
00:44:46,320 --> 00:44:50,280
Speaker 1: Like there's meditation, there's drinking chamma meal.

922
00:44:50,120 --> 00:44:54,799
Speaker 2: Tea, meditation and medication exactly. Well, you know, this sort

923
00:44:54,800 --> 00:44:58,880
Speaker 2: of story of the universe is relaxation. The universe is expanding,

924
00:44:58,960 --> 00:45:01,359
Speaker 2: which means it's getting more elude, which means it's getting

925
00:45:01,560 --> 00:45:06,080
Speaker 2: lower temperature. Right, it's cooling down. As the universe expands,

926
00:45:06,120 --> 00:45:08,840
Speaker 2: the matter gets more and more sparse, and so the

927
00:45:08,960 --> 00:45:11,399
Speaker 2: energy in those fields is going down, down, down, down down.

928
00:45:11,680 --> 00:45:14,080
Speaker 2: So we think about the whole universe as relaxing. All

929
00:45:14,120 --> 00:45:16,640
Speaker 2: the common fields are sort of chill and out heading

930
00:45:16,680 --> 00:45:17,640
Speaker 2: towards zero.

931
00:45:17,840 --> 00:45:19,480
Speaker 1: Wait, what does that mean? Does that mean like a

932
00:45:19,800 --> 00:45:21,719
Speaker 1: field can have a lot of energy and it can

933
00:45:21,840 --> 00:45:22,840
Speaker 1: have a little bit of energy.

934
00:45:23,040 --> 00:45:25,120
Speaker 2: Yeah, fields in the center of the sun have a

935
00:45:25,160 --> 00:45:28,520
Speaker 2: lot of energy. Fields out in intergalactic space have much

936
00:45:28,560 --> 00:45:29,280
Speaker 2: less energy.

937
00:45:29,600 --> 00:45:32,520
Speaker 1: No, But I mean, like as a concept of a field, right, like.

938
00:45:32,840 --> 00:45:36,120
Speaker 2: Well, having multiple particles just means that field is wiggling

939
00:45:36,200 --> 00:45:39,239
Speaker 2: more like the field wiggles, that's one particle. The field

940
00:45:39,239 --> 00:45:42,160
Speaker 2: wiggles more, that's two particles. Field wiggles even more, that's

941
00:45:42,160 --> 00:45:43,200
Speaker 2: a billion particles.

942
00:45:43,440 --> 00:45:45,439
Speaker 1: I guess I was referring to this idea that maybe

943
00:45:45,520 --> 00:45:47,719
Speaker 1: there's a chunk in space out there with nothing in

944
00:45:47,760 --> 00:45:50,640
Speaker 1: it that has fields in it that are vibrating and

945
00:45:50,680 --> 00:45:53,680
Speaker 1: have energy to it. Can that energy be different values?

946
00:45:54,120 --> 00:45:56,399
Speaker 2: So it depends on how space cools, right, It's sort

947
00:45:56,400 --> 00:45:58,200
Speaker 2: of like making a sou fle. You've got to get

948
00:45:58,239 --> 00:46:01,440
Speaker 2: it to that special configuration. So the universe is cooling,

949
00:46:01,520 --> 00:46:04,440
Speaker 2: time is going on, space is relaxing, And then I

950
00:46:04,440 --> 00:46:06,560
Speaker 2: think the question you're asking is like, could it relax

951
00:46:06,600 --> 00:46:09,239
Speaker 2: into different values? Could you have like one state of

952
00:46:09,360 --> 00:46:12,160
Speaker 2: energy over here, another state of lower energy over there?

953
00:46:12,360 --> 00:46:14,839
Speaker 1: Yeah, Like can the electron feel when it relaxes down

954
00:46:14,880 --> 00:46:18,160
Speaker 1: to its minimum? Can it relax down to point one

955
00:46:18,400 --> 00:46:21,560
Speaker 1: or point three or point four or when it relaxes

956
00:46:21,600 --> 00:46:23,760
Speaker 1: there's just one possible relaxation met.

957
00:46:23,920 --> 00:46:27,200
Speaker 2: So almost all the fields relax in a very simple way,

958
00:46:27,239 --> 00:46:30,120
Speaker 2: which is heading towards zero and hitting that minimum, so

959
00:46:30,160 --> 00:46:32,440
Speaker 2: that their average value is zero and they have the

960
00:46:32,520 --> 00:46:35,360
Speaker 2: minimum energy, and that should be the same everywhere in

961
00:46:35,360 --> 00:46:38,799
Speaker 2: the universe. But one field, the Higgs field, has some

962
00:46:38,840 --> 00:46:42,000
Speaker 2: weird wiggles in it and it gets stuck as it cools.

963
00:46:42,040 --> 00:46:45,080
Speaker 2: So the whole universe is cooling down. Everything is settling down,

964
00:46:45,120 --> 00:46:47,920
Speaker 2: sort of rolling towards the bottom of a valley, but

965
00:46:47,920 --> 00:46:50,560
Speaker 2: the Higgs field gets stuck in this false vacuum. Is

966
00:46:50,600 --> 00:46:53,280
Speaker 2: a large amount of energy stuck in it high potential

967
00:46:53,360 --> 00:46:56,800
Speaker 2: energy configuration. While everything else like rolled to the bottom

968
00:46:56,800 --> 00:46:58,600
Speaker 2: of a canyon. It got stuck sort of like on

969
00:46:58,640 --> 00:47:01,799
Speaker 2: a shelf on the canyon wall. So the Higgs field

970
00:47:01,920 --> 00:47:04,040
Speaker 2: is different from all the other fields. It's harder for

971
00:47:04,080 --> 00:47:06,800
Speaker 2: it to relax because the shape of its potential energy.

972
00:47:07,160 --> 00:47:09,200
Speaker 1: I think what you mean is like like if each

973
00:47:09,320 --> 00:47:12,719
Speaker 1: field is like the string and a guitar. All of

974
00:47:12,760 --> 00:47:16,160
Speaker 1: the fields kind of settled down to kind of a

975
00:47:16,200 --> 00:47:19,200
Speaker 1: minimum vibration, but the Higgs field is kind of stuck

976
00:47:19,200 --> 00:47:22,840
Speaker 1: in this kind of high vibration state.

977
00:47:23,000 --> 00:47:25,760
Speaker 2: It's not actually vibrating, and it has high potential energy.

978
00:47:26,120 --> 00:47:29,200
Speaker 2: So while everything else settled down to like the lowest

979
00:47:29,200 --> 00:47:33,000
Speaker 2: possible vibration, it got like stuck in this configuration where

980
00:47:33,000 --> 00:47:35,960
Speaker 2: somebody's pulling it really hard, and it's taught, it's not vibrating,

981
00:47:36,000 --> 00:47:37,960
Speaker 2: there's not a lot of kinetic energy, has a lot

982
00:47:38,000 --> 00:47:40,160
Speaker 2: of potential energy. So the Higgs field sort of like

983
00:47:40,200 --> 00:47:42,239
Speaker 2: got stuck on a bump on the side of your

984
00:47:42,280 --> 00:47:45,760
Speaker 2: guitar and it's pulled sideways and taught and stuck there.

985
00:47:46,960 --> 00:47:49,160
Speaker 1: Like there's a certain curve to the string. Maybe I

986
00:47:49,200 --> 00:47:50,040
Speaker 1: don't know, And so.

987
00:47:50,040 --> 00:47:52,960
Speaker 2: One question is like, is that the true vacuum or

988
00:47:53,000 --> 00:47:54,880
Speaker 2: is that a false vacuum. Is it possible for the

989
00:47:54,920 --> 00:47:57,640
Speaker 2: Higgs field to relax to a lower state, And we've

990
00:47:57,640 --> 00:47:59,640
Speaker 2: talked about that several times, like if the Higgs field

991
00:47:59,640 --> 00:48:02,399
Speaker 2: would collac to a lower potential energy configuration, that would

992
00:48:02,480 --> 00:48:05,400
Speaker 2: change the nature of physics in our universe, and you know,

993
00:48:05,480 --> 00:48:07,360
Speaker 2: all of our atoms would explode at the speed of

994
00:48:07,440 --> 00:48:09,719
Speaker 2: light and all sorts of crazy stuff. But we think

995
00:48:09,800 --> 00:48:13,680
Speaker 2: that probably there are multiple possible vacuum states, and the

996
00:48:13,760 --> 00:48:16,239
Speaker 2: Higgs field is stuck in sort of a false vacuum,

997
00:48:16,360 --> 00:48:19,279
Speaker 2: and the true vacuum is a lower energy configuration that

998
00:48:19,360 --> 00:48:21,600
Speaker 2: it can't quite get to. It's sort of stuck in this.

999
00:48:21,640 --> 00:48:25,680
Speaker 1: Vacuum m like the Higgs field can relax to maybe lower,

1000
00:48:25,719 --> 00:48:27,040
Speaker 1: but for some reason it's not.

1001
00:48:27,360 --> 00:48:29,280
Speaker 2: Yeah, somebody's holding on to that string.

1002
00:48:29,560 --> 00:48:33,160
Speaker 1: It's the finger of God or the God's pick.

1003
00:48:35,960 --> 00:48:39,040
Speaker 2: Maybe God's just in a dad band and that defines

1004
00:48:39,040 --> 00:48:39,920
Speaker 2: the nature of the universe.

1005
00:48:39,960 --> 00:48:42,799
Speaker 1: Yeah, there you go. That's right. And his dad is.

1006
00:48:42,760 --> 00:48:44,960
Speaker 2: Called maximum vacuum.

1007
00:48:45,600 --> 00:48:51,000
Speaker 1: Maximum vacuum. That's right. Now, does God play all the

1008
00:48:51,080 --> 00:48:54,839
Speaker 1: instruments or is he like a one man dad. It's

1009
00:48:54,880 --> 00:48:57,160
Speaker 1: like the Holy Quick quintet, you know.

1010
00:48:57,640 --> 00:48:59,719
Speaker 2: But then all members are actually part of the one.

1011
00:49:00,360 --> 00:49:03,160
Speaker 2: I don't have enough theological background to comment on that

1012
00:49:03,480 --> 00:49:04,640
Speaker 2: without offending.

1013
00:49:04,239 --> 00:49:08,520
Speaker 1: People anyways, So you were saying that maybe like we're

1014
00:49:08,520 --> 00:49:12,120
Speaker 1: not in the most vacuumus of vacuums that the universe

1015
00:49:12,160 --> 00:49:13,880
Speaker 1: can be in, and thankfully.

1016
00:49:13,520 --> 00:49:16,000
Speaker 2: All space out there probably has some particles in it.

1017
00:49:16,440 --> 00:49:19,040
Speaker 2: Even if you were able to remove particles from space,

1018
00:49:19,560 --> 00:49:21,640
Speaker 2: you would have space in this sort of Higgs field

1019
00:49:21,640 --> 00:49:24,600
Speaker 2: that's stuck at a high potential energy. And so yeah,

1020
00:49:24,640 --> 00:49:28,120
Speaker 2: probably nothing out there currently is even capable of getting

1021
00:49:28,120 --> 00:49:31,080
Speaker 2: to the maximum vacuum state that our kind of space

1022
00:49:31,280 --> 00:49:33,719
Speaker 2: is technically capable of achieving.

1023
00:49:35,280 --> 00:49:38,000
Speaker 1: And thankfully right, because if we ever flip to that

1024
00:49:38,400 --> 00:49:41,520
Speaker 1: lower or more vacuum e vacuum, then we're all toast

1025
00:49:41,680 --> 00:49:45,080
Speaker 1: like our universe would kind of get upturned and really suck.

1026
00:49:45,719 --> 00:49:48,200
Speaker 2: Absolutely. We have a whole episode about what would happen

1027
00:49:48,280 --> 00:49:50,759
Speaker 2: if the Higgs field did go to zero, and yeah,

1028
00:49:50,800 --> 00:49:51,840
Speaker 2: it would ruin your life.

1029
00:49:51,880 --> 00:49:53,440
Speaker 1: On the plus that you wouldn't have to vacuum your

1030
00:49:53,480 --> 00:49:54,040
Speaker 1: house anymore.

1031
00:49:54,840 --> 00:49:56,520
Speaker 2: It would be automatically vacuumed.

1032
00:49:57,040 --> 00:49:59,800
Speaker 1: Just room ba our way to a more blissful existence.

1033
00:50:00,520 --> 00:50:03,160
Speaker 1: All right, Well, I think the answer to our question

1034
00:50:03,320 --> 00:50:05,600
Speaker 1: of the episode is that a vacuum, it would be

1035
00:50:05,680 --> 00:50:08,759
Speaker 1: a spot with nothing in it, not even energy. And

1036
00:50:08,880 --> 00:50:11,040
Speaker 1: as far as we know, our universe kind of has

1037
00:50:11,160 --> 00:50:14,080
Speaker 1: something in it everywhere, and so a perfect vacuum it's

1038
00:50:14,120 --> 00:50:16,880
Speaker 1: not possible, and we have to settle for the eighties

1039
00:50:16,920 --> 00:50:20,160
Speaker 1: Coverman maximum vacuum.

1040
00:50:20,280 --> 00:50:23,080
Speaker 2: And when physicists talk about vacuums, that's what they mean.

1041
00:50:23,120 --> 00:50:25,320
Speaker 2: They mean a chunk of space with no particles in it,

1042
00:50:25,360 --> 00:50:29,400
Speaker 2: relaxed to its maximum possible state, which is not zero energy.

1043
00:50:29,840 --> 00:50:32,880
Speaker 1: I feel like physicists are settling then, though. Can't they

1044
00:50:32,920 --> 00:50:34,120
Speaker 1: be striving for perfection?

1045
00:50:34,400 --> 00:50:36,960
Speaker 2: No, we're just defining our achievements as success.

1046
00:50:37,280 --> 00:50:38,800
Speaker 1: I see, you're lowering your standards.

1047
00:50:40,600 --> 00:50:46,840
Speaker 2: We're redefining success. Everyone gets a trophy exactly, participation vacuum.

1048
00:50:46,920 --> 00:50:48,719
Speaker 1: All right, well, I guess the next time you look

1049
00:50:48,719 --> 00:50:52,480
Speaker 1: at into the that's of space, think about the idea

1050
00:50:52,520 --> 00:50:55,440
Speaker 1: that there is nothing out there that is truly nothing.

1051
00:50:56,040 --> 00:50:59,520
Speaker 1: There's always something out there in the universe.

1052
00:51:00,120 --> 00:51:02,200
Speaker 2: Nothingness has a lot of something to think.

1053
00:51:02,080 --> 00:51:05,080
Speaker 1: About that's not nothing. Well, we hope you enjoyed that.

1054
00:51:05,239 --> 00:51:07,879
Speaker 1: Thanks for joining us, see you next time.

1055
00:51:15,800 --> 00:51:18,600
Speaker 2: Thanks for listening, and remember that Daniel and Jorge explain

1056
00:51:18,680 --> 00:51:22,680
Speaker 2: the Universe is a production of iHeartRadio. For more podcasts

1057
00:51:22,680 --> 00:51:27,320
Speaker 2: from iHeartRadio, visit the iHeartRadio app, Apple Podcasts, or wherever

1058
00:51:27,400 --> 00:51:29,120
Speaker 2: you listen to your favorite shows.