Speaker 1: Welcome to Scoot to Blow Your Mind production of My
Speaker 1: Heart Radio. Hey you welcome to Stuff to Blow Your Mind.
Speaker 1: My name is Robert Lamb and I'm Joe McCormick. And
Speaker 1: today we have got a special treat for you. Returning
Speaker 1: champion previous guests to the show, Daniel Whiteson of Daniel
Speaker 1: and Jorge Explain the Universe. We are so privileged to
Speaker 1: have Daniel join us again today. Daniel, say hi and
Speaker 1: introduce yourself. For anybody who wasn't around last time, Hi guys,
Speaker 1: thanks so much for having me on. Great to be back. Um.
Speaker 1: I'm Daniel Whitson. I'm a professor of particle physics at
Speaker 1: u c Irvine down here in southern California, and I'm
Speaker 1: also the co host of the podcast Daniel and Jorge
Speaker 1: Explain the Universe, a podcast with my good friend and
Speaker 1: collaborator Jorge cham in which we talk all about the
Speaker 1: craziness of the universe. We try to answer questions, We
Speaker 1: try to share the wonder and the mystery of the
Speaker 1: uni verse in a way that makes it accessible and
Speaker 1: hopefully a little bit fun. Well, we really appreciate you
Speaker 1: joining us today, Daniel. So I wanted to invite you
Speaker 1: onto stuff to blow your mind today to talk about space.
Speaker 1: This is actually a subject I've I've wanted to tackle
Speaker 1: on the show for a while with uh, the unifying
Speaker 1: question of what is space? Why is there such a
Speaker 1: thing as the distance between the Earth and the Sun,
Speaker 1: or between an atomic nucleus and the electron that orbits it.
Speaker 1: Because I think a lot of the time when we
Speaker 1: think about physical reality, we just immediately look past space
Speaker 1: to the things that occupy it. We we assume space
Speaker 1: as a kind of given, a de facto canvas on
Speaker 1: which physics can be realized. But I wanted to think
Speaker 1: about space itself. What is it? How does it exist?
Speaker 1: Do we know anything about where it comes from and
Speaker 1: where it's going? So maybe the easiest way to start
Speaker 1: off today would be to to get as simple as
Speaker 1: we can so in simplest terms in a sentence, if
Speaker 1: you could do it, how would a physicist define space?
Speaker 1: While all of space in one sentence? That is a
Speaker 1: pretty tall order, you know, I have to say, to
Speaker 1: be honest, I'd have to say, we really have no
Speaker 1: idea what space is. I mean, I think it's wonderful
Speaker 1: that you're asking this question. It's the kind of question
Speaker 1: that it takes like a sort of maturity of science
Speaker 1: and philosophy to even understand why the question is interesting
Speaker 1: and important. You know. It's like it's like we're have
Speaker 1: been fish scientists for a thousand years swimming through this fluid,
Speaker 1: and then only recently have realized that it's it's something fascinating,
Speaker 1: something to study, something that has property, something can do
Speaker 1: weird things. And so it's a it's a deep and
Speaker 1: important question, you know. And and just to digress a
Speaker 1: tiny bit more like it makes me wonder how many
Speaker 1: other crazy basic questions we aren't even asking because we
Speaker 1: don't realize how rich the topic is, you know. So
Speaker 1: I feel sort of privilege that we're at this moment
Speaker 1: in science when we can ask this question what is
Speaker 1: space and understand that it is an important question? Alright,
Speaker 1: So I totally dodged your question there, But I could
Speaker 1: try to give a one sentence answer if if you'd like, sure,
Speaker 1: we'll start simple and then and then we'll get more
Speaker 1: into the nuances here. All right, Well, a simple answer
Speaker 1: to what is space? Is that? Oh man? I mean
Speaker 1: I could try to maybe impossible, um, I'd say the
Speaker 1: simplest description I could give for what space is is
Speaker 1: something which has various properties. We've discovered it can contain
Speaker 1: quantum fields, it can expand, and it has relationships to
Speaker 1: other parts of space. And so that's more a description
Speaker 1: of like what we've what we've observed about space. It's
Speaker 1: not really an inherent understanding of what it is because
Speaker 1: we don't have that understanding. Well, maybe this brings me
Speaker 1: to a question I wanted to ask later on. But
Speaker 1: if there is no good answer to this, it can
Speaker 1: help ground us as we go forward. So I wanted
Speaker 1: to ask, is there such a thing as even a
Speaker 1: hypothetical physics without space? Does all physics assume space? And
Speaker 1: can we imagine, say a possible world that exists but
Speaker 1: does not contain space, or is that just inconceivable? Now?
Speaker 1: I think that all physics that we do assume space,
Speaker 1: Like all of our modern theories, the standard model and
Speaker 1: quantum field theory, they all operate in some space. And
Speaker 1: there are different kinds of theories that we have, and
Speaker 1: some of those make different assumptions for what that space is.
Speaker 1: Like quantum field theory, you write down with the spaces
Speaker 1: in advance. You say I'm gonna assume space. You know
Speaker 1: is three dimensions and extents in all in all these directions,
Speaker 1: and then I'm going to talk about the fields that
Speaker 1: are in that space. Other theories like general relativity. Space
Speaker 1: is a part of what you're sort of trying to
Speaker 1: get at. It's not like the backdrop. It's the thing
Speaker 1: you solve for. You say, if I have this configuration,
Speaker 1: then what does the space look like? But they all
Speaker 1: assume space. I mean space gives you a relationship between stuff, right,
Speaker 1: tells you this is here and this is not here.
Speaker 1: And in the end, all of our theories are trying
Speaker 1: to understand the world we live in, and everything we
Speaker 1: live in has space. So it's pretty hard to grapple
Speaker 1: with a non spatial theories or non spatial physics. So yeah,
Speaker 1: I would say that we need space, okay, But so
Speaker 1: if we could come at it from the exact opposite
Speaker 1: angle you think, you you couldn't really have a physics
Speaker 1: without space. Could you have a universe full of space
Speaker 1: with no matter of energy in it? Could space exist
Speaker 1: without any contents? Could space exists without any contents in it? Yeah?
Speaker 1: That is an awesome question, and it's fascinating because we
Speaker 1: have two theories of physics right now, quantum mechanics and
Speaker 1: general relativity, and they're both awesome achievements, staggering insights into
Speaker 1: the way the universe works, and they give different answers
Speaker 1: to this question. Right, So general activity um is Einstein's theory.
Speaker 1: And he has a bunch of equations. Let's say, what
Speaker 1: the universe look like depending what you put in it,
Speaker 1: and he has and one of the and it's really
Speaker 1: hard to solve, like, there's very few ways you can
Speaker 1: actually solve these equations. One of the very few ways
Speaker 1: you actually can get an answer out is what they
Speaker 1: call the vacuum solution, like to say, assume there's nothing,
Speaker 1: then what does the universe look like? If there's nothing
Speaker 1: in it? All? Right? Einstein can solve that problem quantum
Speaker 1: field theory. Though, quantum field theory says, hold on a second,
Speaker 1: um space is filled with all these quantum fields and
Speaker 1: particles and matter and all the stuff that you make
Speaker 1: me and you are just like excited states of these fields.
Speaker 1: So when you look at an electron, it's not a particle,
Speaker 1: it's not a wave. It's a little ripple in some
Speaker 1: field which is not in space. It's part of space.
Speaker 1: So if all these fields. You have the electron field,
Speaker 1: the electromagnetic field, all the fields associated with each of
Speaker 1: the forces. As lots of them. We can talk about
Speaker 1: them later if you'd like. But some of them never
Speaker 1: relax completely. Some of them are always have some energy
Speaker 1: in them, for example, the Higgs field. The Higgs field
Speaker 1: is in every part of space, and it's always got
Speaker 1: some built intention to it, and that means that there's
Speaker 1: energy in every part of space. So quantum field theory says, no,
Speaker 1: you can't have space without some energy in it. There's
Speaker 1: some inherent energy to space, where the general relativity says,
Speaker 1: I could totally imagine it. And we don't know which
Speaker 1: theory is the fundamental, true theory of the universe. If
Speaker 1: either one, we can't seem to make them play together
Speaker 1: very well. And so this question really goes to the
Speaker 1: heart of the nature of reality itself. It's fascinating. It's
Speaker 1: the kind of thing that in five years physicists will
Speaker 1: know the answer to and look back at us and
Speaker 1: be like, oh, man, those people didn't understand anything about
Speaker 1: the nature of the universe they were living in, right,
Speaker 1: What a bunch of cave men and cave women like
Speaker 1: they were subjignary misses. So I love that idea about
Speaker 1: quantum field theory. And if I understand this right, you're
Speaker 1: saying that under the assumptions of quantum field theory, you
Speaker 1: could have a big block of space, and even if
Speaker 1: you were able to clear everything out of it, clear
Speaker 1: out all the hydrogen particles, clear out all the dust,
Speaker 1: so there's no matter left in it, you'd still you
Speaker 1: still really wouldn't have an empty void. Is that correct?
Speaker 1: That's right. Every unit of space comes with energy built
Speaker 1: in it comes from the factory with energy already in it,
Speaker 1: and um and and lots of those fields cannot cannot relax.
Speaker 1: The Higgs field is one example, but many of these
Speaker 1: fields cannot relax all the way down to zero. And
Speaker 1: so it's impossible, according to these quantum theories, to have
Speaker 1: space with no energy density in it at all. And
Speaker 1: that means and that's stuff, right, All stuff is is
Speaker 1: some kind of energy, like the matter that makes it
Speaker 1: me and you. That's just a form of energy. So
Speaker 1: to say that this space has energy in it really
Speaker 1: means it's not empty. So what you're describing space as
Speaker 1: really goes against a lot of our intuitions, where you know,
Speaker 1: I think the standard understanding of empty space what's out
Speaker 1: there beyond Earth, you know, even if you could clear
Speaker 1: all the hydrogen and dust and everything out of it,
Speaker 1: is that it's just this empty relationship between two points.
Speaker 1: But you mentioned, of course, the the idea that there,
Speaker 1: you know, quantum fields that can be excited and can
Speaker 1: give birth to particles and stuff. Well, I might be
Speaker 1: putting words in your mouth. There is that correct though. Yeah, okay,
Speaker 1: but earlier you mentioned also that it has other properties,
Speaker 1: So it sounds like you're saying space really is a thing.
Speaker 1: It's almost like a substance of a kind. Yes, space
Speaker 1: is a goo. Right. We first imagine space sort of
Speaker 1: as a place to hold our ideas, right where like
Speaker 1: maybe when you think space and you think a deep space,
Speaker 1: you imagine some like glowing x y z axes that
Speaker 1: used to like the backdrop on which maybe your calculations
Speaker 1: take place or your spaceship flies through or whatever sort of.
Speaker 1: But they're like mental metrics we use to understand where
Speaker 1: things are. That sort of the initial idea of space.
Speaker 1: But then it turns out the space can do things
Speaker 1: that are inconsistent with that, right, Like space can ripple
Speaker 1: we've seen gravitational waves. When black holes orbit each other
Speaker 1: and eventually collide or other things happen, they create these
Speaker 1: ripples in space itself. These ripples, they're space getting stretched
Speaker 1: and space getting contracted, right, squeezing and shrinking and then
Speaker 1: expanding again, and very very very small, which is why
Speaker 1: they were hard to discover. But yes, we've discovered that
Speaker 1: space can do things. So it can ripple, it can expand, right,
Speaker 1: We've talked about the expansion of the universe, the universe
Speaker 1: expanding its first moments, and it's continuing to expand. In addition,
Speaker 1: space can bend. Maybe the most familiar example is understanding
Speaker 1: gravity as distortions in space by having mass nearby and
Speaker 1: and so space can do all these things that nothingness
Speaker 1: cannot do, that a backdrop cannot do. You can't just
Speaker 1: think of spaces like the theater of the universe. It's
Speaker 1: a weird dynamical thing in itself. Yeah, I think in
Speaker 1: general our listeners are going to be more familiar with
Speaker 1: the idea that space can can bend in accordance with
Speaker 1: general relativity. There's a big object, you know, and that
Speaker 1: creates curvature, and in spacetime it's a little bit harder
Speaker 1: to picture exactly what's happening with the first thing you
Speaker 1: mentioned with the ripples through spacetime. So that's something that
Speaker 1: would be like, that's like how we detected gravitational waves, right,
Speaker 1: is that correct? Um? So what what exactly is happening
Speaker 1: when a ripple goes through space? Like? How do how
Speaker 1: do you measure that? What? What is that in the moment? Right? Well,
Speaker 1: you know, a ripple through space is information propagating through
Speaker 1: the gravitational field. Something that's very important that came out
Speaker 1: of general relativity that we didn't have with Newton's gravity
Speaker 1: is the concept that information takes time to move gravitationally.
Speaker 1: Like if the Sun disappeared, would we feel the Sun's
Speaker 1: gravity instantly disappear or would it take a moment? Turns
Speaker 1: out Newton says it would go away instantly. Einstein says, no,
Speaker 1: you wouldn't even notice for eight minutes because the gravity
Speaker 1: from the Sun would take The information about the Sun
Speaker 1: being gone would take eight minutes to get here gravitationally,
Speaker 1: And so that's propagation of information. And so gravitational wave
Speaker 1: is a special form of that. Say you're familiar with
Speaker 1: the concept of like putting a mass and that deforms space.
Speaker 1: We'll imagine you put a mass in space, and then
Speaker 1: you take it away, and you put it in space,
Speaker 1: and you take it away, and you put in space
Speaker 1: and you take it away. What's going to happen, Well,
Speaker 1: you know it's not gonna be very pleasant for the
Speaker 1: occupants of your space. They're gonna get jerked around, right,
Speaker 1: It's back and forth and back and forth. And that's
Speaker 1: sort of a more dramatic version of what happens when
Speaker 1: two black holes orbit each other. Is they're creating ripples
Speaker 1: in this gravitational field, and you feel those as stretching
Speaker 1: and squeezing of space itself. And we measured that here
Speaker 1: on Earth by having really long rods essentially and watching
Speaker 1: them shrink and expand shrink and expand. With those north
Speaker 1: there would be like lasers that you would use to
Speaker 1: measure that. Yeah, the practical way you measure a very
Speaker 1: small change in the length of a long rod is
Speaker 1: that you don't actually of the physical rods. That was
Speaker 1: the first thing they tried, actually did that here, you see,
Speaker 1: I Jo Webber did that, and it's because he had
Speaker 1: no idea like maybe this is easy to spot right,
Speaker 1: let's just build a big block of metal and see
Speaker 1: if its shrinks and expands. I was gonna say, what
Speaker 1: was it made out of? Yeah, it's just a big
Speaker 1: cylinder of metal. Um. But nowadays they're miles long and
Speaker 1: their laser and they use lasers to measure the length
Speaker 1: between two isolated mirrors. And I think that the biggest
Speaker 1: misconception people have about space being bent by mass is
Speaker 1: that they're used to this rubber sheet analogy where you
Speaker 1: have like a big rubber sheet and you put a
Speaker 1: bowling ball in it and it bends space. And the
Speaker 1: bowling ball is supposed to represent the sun and the
Speaker 1: rubber sheet is supposed to represent space. And that's helpful
Speaker 1: up to a point because it gets you to think
Speaker 1: about space being bent instead of flat. But it's also
Speaker 1: I think confusing. And the way it's confusing is that
Speaker 1: it's bending in some sort of third dimension, right, and
Speaker 1: that analogy space the universe is two D and you
Speaker 1: put some object in it and it bends in some
Speaker 1: third dimension. But our space it's three D. First of all,
Speaker 1: when you put a mass in it, it doesn't bend
Speaker 1: in some fourth dimension. It's not like our space is
Speaker 1: embedded in some higher dimensional space and then it gets
Speaker 1: bent in fourth dimension. It's an intrinsic bending, not an
Speaker 1: extrinsic It's not like there's somebody out there with a
Speaker 1: true set of rulers in four D space and they're
Speaker 1: noticing our space being bent. It's an intrinsic bending, which
Speaker 1: means it just changes the relationship between points in space.
Speaker 1: Right it says, Okay, now that space, that bit of
Speaker 1: space is closer and this bit of a space is
Speaker 1: further away. Wow. So I've never thought of it that way. So,
Speaker 1: so you're saying that the gravitational influence of a large
Speaker 1: object like a star is in some literal sense shortening
Speaker 1: the distance between points of space as you get closer
Speaker 1: to it. Absolutely. You know, massless particles like photons travel
Speaker 1: not in straight lines. They travel along geodesics, which means
Speaker 1: the shortest path through curved space. Now out in the
Speaker 1: middle of nowhere, there's no mass anywhere that happens to
Speaker 1: be a straight line. That's why it seems like photons
Speaker 1: travel straight. But photons can also be bent by the sun.
Speaker 1: How does that happen? Photons have no mass, right, Well,
Speaker 1: the the Sun is changing the shape of space, so
Speaker 1: that the shortest path from A to B is no
Speaker 1: longer what we would consider a straight line. It's a geodesic.
Speaker 1: It's the shortest path. And so general relativity and mass
Speaker 1: changes the relationship between space between here and there, and um,
Speaker 1: that's what we maybe you hear people talk about like
Speaker 1: the spacetime metric that relates like how bits of space
Speaker 1: are connected. So this is sort of the biggest conceptual
Speaker 1: leap to make from the rubber sheet analogy to our
Speaker 1: actual three D space, which is that it's an intrinsic bending.
Speaker 1: It's a relationship between points in space, and that's what
Speaker 1: a gravitational wave is doing. Also, it's a ripple in
Speaker 1: this metric as it passes through space, and it's saying, oh,
Speaker 1: these things are now closer together, now the further apart.
Speaker 1: Like you can change the distance, but weeen two things
Speaker 1: without those things moving relative to each other, right, because
Speaker 1: you change the relative distances. Well, it almost makes me
Speaker 1: think in terms of how this is communicated to non experts,
Speaker 1: that would maybe be better to not use terms like
Speaker 1: bending of space and maybe more like compressing or squeezing
Speaker 1: of space. Yeah, but space can also be expanded, right,
Speaker 1: like what we're seeing in the universe right now is
Speaker 1: that space is expanding, which is crazy. It's like something
Speaker 1: out there is manufacturing new units of space all the time.
Speaker 1: It's filling the universe with new space. Like that's that's
Speaker 1: the hardest thing for me to get my mind around.
Speaker 1: It's like where this new space is coming from, what
Speaker 1: it means to make new space? And are you making
Speaker 1: units of new space? There's space continuous and smooth and like, man,
Speaker 1: there's so many questions. Oh well, I want to talk
Speaker 1: about that. Maybe we should take a quick break and
Speaker 1: then when we come back we can explore the expansion
Speaker 1: of space. Sounds good than all? Right, we're back. We're
Speaker 1: talking with Daniel Whitson about space, the nature of space.
Speaker 1: That's right. So before we went to the break, Daniel,
Speaker 1: you just introduced the idea of the expansion of space.
Speaker 1: As we've we've been talking about the properties of space
Speaker 1: as a as a thing and not just an emptiness. Uh.
Speaker 1: And so of course we know one of the things
Speaker 1: that space is doing is that it's expanding. Uh. I
Speaker 1: think we all know now that the universe as a
Speaker 1: whole is expanding and maybe expanding at an accelerating rate.
Speaker 1: If I've got that writing, comment on that in a second.
Speaker 1: What exactly does it mean for space to expand? Because
Speaker 1: I think from an intuitive level, people might think, well,
Speaker 1: I don't notice space expanding, Like I don't notice it
Speaker 1: doesn't seem like the space in between the molecules in
Speaker 1: my body is expanding. So so is space in general
Speaker 1: expanding or is it just say, the distance between galaxies
Speaker 1: is expanding. What form does that expansion take? Yeah, it's
Speaker 1: a great question. I love the intuition there. You know.
Speaker 1: The idea is like this thing is supposed to be
Speaker 1: happening everywhere in the universe. Kind of sort of reconcile
Speaker 1: that with my experience. Can I see that happening around me?
Speaker 1: And you know, like a few hundred years ago, that
Speaker 1: was a big conceptual leap to say like the rules
Speaker 1: of the universe should also being applied here. Um. So
Speaker 1: it's a great question. And and the short answer is
Speaker 1: that space is expanding everywhere, Like every unit of space
Speaker 1: is the same. It's homogeneous as far as we understand.
Speaker 1: There's no difference to this chunk of space and a
Speaker 1: chunk of space out there in the deepest voids between galaxies.
Speaker 1: They're all the same from the point of view of
Speaker 1: the universe, and they're all expanding, which means they're all
Speaker 1: creating new space. But that's not the only thing happening, right.
Speaker 1: You are made of a mesh of atoms that are
Speaker 1: held together with pretty strong bonds, and this expansion of
Speaker 1: space is dramatic, but per unit of space, it's pretty small.
Speaker 1: Like there's not a whole lot of space being made
Speaker 1: between me and this microphone, for example. It adds up
Speaker 1: when you get to like cosmic scales between me and
Speaker 1: the galaxy, because there's a lot of space between us,
Speaker 1: but here on the small scale, it's not very powerful,
Speaker 1: so the bonds in my body are strong enough to
Speaker 1: hold me together. The same thing said for you know
Speaker 1: the reason why you're staying on Earth. You know, Earth
Speaker 1: is holding you down because if it's gravity, that's enough
Speaker 1: to overcome this expansion of space, and Earth is bound
Speaker 1: gravitationally to the Sun for the same reason. The space
Speaker 1: between us and the Sun is expanding, but the gravity
Speaker 1: the Sun holds us there. It's like if you were
Speaker 1: sliding away from somebody on an ice sheet, but they
Speaker 1: had a rope around you, and so they were keeping
Speaker 1: you at a fixed distance. Okay, so there are forces
Speaker 1: within our bodies, holding our bodies together that are counteracting
Speaker 1: that expansive force. But I'm trying to imagine what exact
Speaker 1: form does that take. So does that mean that the say,
Speaker 1: the bonds between the molecules and our body holding them
Speaker 1: together actually prevent the space from expanding there so it
Speaker 1: doesn't expand, or does the space somehow kind of roll
Speaker 1: out beyond us without affecting our you know, our bodies
Speaker 1: as it does. So you can't stop the expansion of space,
Speaker 1: but you can't and keep your constant distance. If those
Speaker 1: bonds were deleted, then all the items would sort of
Speaker 1: drift further and further apart, but instead you have these
Speaker 1: bonds holding them together. And so it's more of that
Speaker 1: the answers the latter, that space sort of rolls out
Speaker 1: past you. So space is emanating from us at all times. Yeah,
Speaker 1: it's sort of like we're in a pool of space
Speaker 1: that's expanding larger and larger, and we're a smaller and
Speaker 1: smaller dot inside of it. So as a result, you know,
Speaker 1: the universe is getting getting more and more dilute, like
Speaker 1: the matter energy density of the universe decreases with time
Speaker 1: because there's no more stuff being created, but there is
Speaker 1: more space being created all the time. And so that's
Speaker 1: really like the way to think about the whole expansion
Speaker 1: of the universe since the Big Bangs, that the universe
Speaker 1: didn't start out small. It started out dense. It was
Speaker 1: like compressed and hot and nasty and wet, and then
Speaker 1: the Big Bang is just this rapid dilution of space
Speaker 1: into something much more sparse, and then that's just continued.
Speaker 1: The universe has just gotten more and more cold and
Speaker 1: dilute and spread out as new spaces being created and
Speaker 1: these little chunks of matter desperately clinging to each other
Speaker 1: to avoid being totally isolated. And I think there's another
Speaker 1: part of your question which I think is fascinating, is
Speaker 1: like at what scale does that take over? Like you
Speaker 1: hold yourself together, Yeah, the Earth holds onto you, the
Speaker 1: Sun holds onto the Earth, the galaxy holds onto the
Speaker 1: Sun and all the stars, and dark energy is probably
Speaker 1: not going to rip apart our galaxy, and even the
Speaker 1: neighboring galaxies like Andromeda is going to collide into us,
Speaker 1: and the direct gravity these two galaxies are going to
Speaker 1: smash them together, and the group of galaxies is mostly
Speaker 1: gravitationally bound, and that's the biggest sort of gravitationally bound thing.
Speaker 1: Beyond that, things are not tightly connected enough by gravity
Speaker 1: to resist dark energy. And that's so it's these groups
Speaker 1: of galaxies that are getting pushed apart and getting further
Speaker 1: and further away because there's nothing really to resist the
Speaker 1: dark energy push. Okay, So the reason then that you
Speaker 1: would normally see the expansion of the universe expressed in
Speaker 1: terms of like the separation of what galaxy clusters or
Speaker 1: what it would be that that's where gravity is no
Speaker 1: longer strong enough to hold back against it. And it's
Speaker 1: not just the amount of distance, you know, causes the
Speaker 1: uh causes all the expansion to add up there, That's right,
Speaker 1: It's it's both things. I mean, the the amount of
Speaker 1: distance makes it more dramatic, and the distance makes gravity weaker.
Speaker 1: And so what you think which happens if you sort
Speaker 1: of project the universe forward billions or trillions of years,
Speaker 1: is that these gravitationally bound clusters continue to contract and
Speaker 1: hold themselves together, but they get more and more distant
Speaker 1: from everything else. So the future is is islands of
Speaker 1: stuff separated by even more vast distances of space. It's interesting.
Speaker 1: So all of this talk about space as a substance
Speaker 1: and having all these properties that we can measure and
Speaker 1: not just as a you know, uh, the void or
Speaker 1: the distance between things is uh somehow on on one level,
Speaker 1: kind of makes a lot of these like sci fi
Speaker 1: plots where you manipulate space itself with technology seem more plausible. Robert,
Speaker 1: I think you had some questions about this, maybe right, yeah, yeah,
Speaker 1: this this got me thinking, you know about the expansion
Speaker 1: explosive expansion. H Daniel, what do you make of the
Speaker 1: notion that faster than light travel could essentially be achieved
Speaker 1: by some manner of of work bubble manipulation moving the
Speaker 1: space containing the ship rather than the ship through space alone. Oh,
Speaker 1: I'm ready to invest in your work drive company for sure. UM.
Speaker 1: I read a lot of science fiction, and um, I
Speaker 1: love these ideas. And there's a lot of bolognay and
Speaker 1: science fiction where they just like slap quantum mechanics on
Speaker 1: a plot hole because they don't really know how to
Speaker 1: think about it. But I give people a lot of
Speaker 1: flexibility when it comes to space because we really don't
Speaker 1: know what he can do. And there's a lot of
Speaker 1: opportunities there for new ideas. And the one that you
Speaker 1: mentioned I think is is a great um idea and
Speaker 1: it's not just science fiction. I think it really could
Speaker 1: be that we could develop a warp drive that that
Speaker 1: gets us two distant stars. You know, there's one very
Speaker 1: hard and fast rule about the universe, which is you
Speaker 1: cannot move through space faster than the speed of light.
Speaker 1: But you've gotta be a bit of a lawyer about it, right,
Speaker 1: You're gonna be like, what on a second, you said
Speaker 1: move through space? Right? That's fine, so you can't travel
Speaker 1: through a light year of space in less than a year.
Speaker 1: But what if you didn't want to move through space? Right?
Speaker 1: What if you squeeze space itself? Right? Or if you
Speaker 1: stretch space? And that's the basis of these warp drive
Speaker 1: ideas is to get around it by saying I don't
Speaker 1: want to go all the way to Alpha Centauri. I
Speaker 1: want to squeeze the distance between here and Alpha Centauri.
Speaker 1: Or I want to create this warp bubble which continuously
Speaker 1: is like squeezing the space in front of me, so
Speaker 1: I can move really really fall What what what would
Speaker 1: have been otherwise really far in a short amount of time,
Speaker 1: and and that way you can get somewhere which would
Speaker 1: have taken light a long time to get there, but
Speaker 1: it only takes you a few moments because you've effectively
Speaker 1: shortened that distance. So I think that's totally plausible. Um,
Speaker 1: I think it's far, far beyond our abilities. You know,
Speaker 1: it's sort of like this moment when physicists pass things
Speaker 1: off to engineers, you know, like we're interested in is
Speaker 1: it totally possible or totally impossible. Once we decide it's
Speaker 1: probably possible, then it's a practical question of like how
Speaker 1: do you focus that much energy in order to accomplish that?
Speaker 1: How do you actually build something which does this? And
Speaker 1: that's a whole separate question. And you know, there are
Speaker 1: even other crazier ideas for how to get far through
Speaker 1: space which take advantage of this this new sort of
Speaker 1: modern conception of space, and that's like, don't even go
Speaker 1: through any space at all. General relativity tells us that
Speaker 1: you can be creative about assigning the distances between bits
Speaker 1: of space. Right, it doesn't have to be you lay
Speaker 1: out a grid and everything that's next to each other
Speaker 1: has equal distances. Right, mass can change the relationship of
Speaker 1: points in space. And it's more than just like taking
Speaker 1: a she and stretching it and squeezing it to make
Speaker 1: gentle differences. You can have crazy rear arrangements. You can
Speaker 1: connect bits of space which are not adjacent to each other.
Speaker 1: And that's what we call a wormhole, is a connection
Speaker 1: between bits of space which you know, have no reason
Speaker 1: otherwise to be next to each other. But it's like,
Speaker 1: I'm here in Orange County, you're in Atlanta. What if
Speaker 1: we just somehow said Orange County is next to Atlanta,
Speaker 1: and you know, we just rearrange the connections. That's what
Speaker 1: a wormhole does. And shockingly, crazily, mind bogglingly that's not
Speaker 1: against the rules. Yeah, this makes me think of the
Speaker 1: examples we saw in the Hyperion novels where you had, uh,
Speaker 1: you know, essentially warp gates that were allowing a river
Speaker 1: in one world to flow into a river in the
Speaker 1: other world, which, you know, if it feels completely fantastic,
Speaker 1: but what what you're saying, if you lawyer up appropriately,
Speaker 1: it's not completely out of the realm of possibility. Yeah,
Speaker 1: it's not out of the realm of possibility at all.
Speaker 1: And it's the kind of thing which might never be practical.
Speaker 1: They might be that we're never able to build something
Speaker 1: which allows you to have a house where your bathroom
Speaker 1: is in one planet, in your living room is another.
Speaker 1: I love that book, Um, But also might be totally possible,
Speaker 1: and it might be seem impossible, and then somebody has
Speaker 1: a breakthrough, like, oh, it turns out it's a lot
Speaker 1: easier than we thought. And it used to cost um
Speaker 1: the entire energy output of the human race for a
Speaker 1: year just to transmit a particle through a wormhole. Now
Speaker 1: we can do it for or five cents, you know,
Speaker 1: and then the next year that's an app for it, right,
Speaker 1: and sort of the progression of technology, And you know,
Speaker 1: the way a wormhole would work is conceptually quite tricky. Still.
Speaker 1: You need to create a black hole, you need to
Speaker 1: open this wormhole up, you need to keep it open.
Speaker 1: It might require the creation of exotic matter and all
Speaker 1: sorts of stuff, but it's tactically not impossible. And that's
Speaker 1: that's excite to me, um, mostly because I'd love to
Speaker 1: visit these other star systems and walk on another planet,
Speaker 1: or at least have humans walk on other planets and
Speaker 1: tell us about it, you know, um, it feels frustrated
Speaker 1: to be stuck in this tiny little island of our
Speaker 1: universe and not able to explore the neighborhood. And so
Speaker 1: if warp drives and wormholes could be built, then I'm
Speaker 1: all for it. So yeah, I'd love to invest in
Speaker 1: your company. So to come back to another question about
Speaker 1: the properties of space, I was thinking about, um, So
Speaker 1: we think of space as a kind of undifferentiated, uncountable
Speaker 1: mass of potentially occupied territory, kind of the way you
Speaker 1: use the analogy of water earlier, the way we think
Speaker 1: about water. But of course in the modern world we
Speaker 1: know that water is not actually continuous and uncountable. It's
Speaker 1: a made up of h two molecules. In theory, you
Speaker 1: could separate them out and count them. Is there any
Speaker 1: evidence that space works like that? Are their smallest indivisible
Speaker 1: units of space that could be counted? And does anybody
Speaker 1: have any ideas for how to look into this question? Yeah,
Speaker 1: that's a wonderful question. The short answer is that we
Speaker 1: think space should be pixelated, and we think that there
Speaker 1: should be a smallest meaningful unit of space. But the
Speaker 1: arguments are kind of fuzzy, and it goes something like this,
Speaker 1: you know, we look around in the universe and we
Speaker 1: see that everything at the smallest scale is quantized. Like
Speaker 1: you can have one electron, you can have two electrons.
Speaker 1: You can't have one point six one electrons. Electrons in
Speaker 1: bound states have energy levels. You can be an energy
Speaker 1: level one or two. You can't be at one point
Speaker 1: to one. Right, the universe seems to be quantized everything,
Speaker 1: excitations of quantum fields. Everything comes down to numbers, integers,
Speaker 1: not real numbers, but integers. And so we imagine that
Speaker 1: as we zoom in on space smaller and smaller and smaller,
Speaker 1: that we should similarly see the smallest bit of space.
Speaker 1: It would sort of be counter a lot of what
Speaker 1: we imagine to be foundational to quantum mechanics if it
Speaker 1: wasn't right, if you could always zoom into a smaller space.
Speaker 1: And so there's this idea that space could be made
Speaker 1: out of these basic units, these pixels. And you can
Speaker 1: think of it either it's like space being pixels or
Speaker 1: space being sort of made out of this foam um.
Speaker 1: And you know, that's not a very strong argument, but
Speaker 1: it's it's consistent. You know, you find these general principles
Speaker 1: who say, hey, the universe seems to work this way,
Speaker 1: and so it should work this way in all categories.
Speaker 1: It should every part of it should follow these rules.
Speaker 1: Are there any ideas for types of experiments that could
Speaker 1: test for this right now? Where is? That's just totally
Speaker 1: beyond our even guests of how to how to look
Speaker 1: for right now? Well, it's hard to know because we
Speaker 1: don't know how big these pixels should be. Right we
Speaker 1: let's think about scales for example, like we can look
Speaker 1: at really small things using particle colliders. For example, with
Speaker 1: a large hadron collider at certain we can zoom in
Speaker 1: and see things that are about ten to the minus
Speaker 1: twenty meters. That's pretty small, um. But if we had
Speaker 1: to make a guess for how small these space pixels
Speaker 1: would be, we don't really have a lot of good
Speaker 1: reasons to guess. And what we do is we just
Speaker 1: sort of take all the numbers we have and we
Speaker 1: rearrange them until they give us something that have units
Speaker 1: of a meter. We're like, okay, take the speed of light.
Speaker 1: You know, that's meters per second multiplied by planks constant. Alright,
Speaker 1: that has energy units. So keep throwing in fundamental constant
Speaker 1: to the universe until you get something that has units
Speaker 1: of meters, and you can do it, and you get
Speaker 1: a number, and that number is about ten to the
Speaker 1: minus thirty five meters, and it's called the plank length.
Speaker 1: And it sounds like a really deep insight. I mean,
Speaker 1: it's really nothing more clever than dimensional analysis. It's just saying,
Speaker 1: how can I get a unit of meter? Doesn't mean
Speaker 1: that that's the fundamental scale of the universe, doesn't mean
Speaker 1: that space pixels are that size, but it's the only
Speaker 1: thing we can do. And often in science we start
Speaker 1: with like, let's start with the dumbest idea because that's
Speaker 1: all we can do, and then let's get more sophisticated.
Speaker 1: So if that's the case, and if space pixels are
Speaker 1: ten to the minus thirty five meters, that's really far
Speaker 1: from what we can see today, right, that's fifteen orders
Speaker 1: of magnitude from what we can see. That's like, if
Speaker 1: you can see whole solar systems, then one over one,
Speaker 1: one over ten of the fifteen would be like seeing
Speaker 1: a meter stick. So it's like saying I can barely
Speaker 1: detect solar systems and other galaxies. Okay, well, can you
Speaker 1: see a meter stick on the surface of a planet?
Speaker 1: In another galaxy. No, I mean we're not even close.
Speaker 1: So we're trillions of scale factors away from being able
Speaker 1: to see these things in particle collisions. Um. But there's
Speaker 1: a whole area of research that's built up the other directions.
Speaker 1: Let's start from the bottom instead of starting from the
Speaker 1: top and like breaking up protons and electrons into smaller
Speaker 1: bits all the way down to the plank scale, Let's
Speaker 1: start from the bottom. Imagine that it's true. Can we
Speaker 1: sort of build up and come up with the theory
Speaker 1: of physics and then make a prediction? Right? And that's
Speaker 1: this this group of of theories called loop quantum gravity,
Speaker 1: and it's really fascinating stuff, and it's you know, they've
Speaker 1: instead of trying to bring general relativity together with quantum
Speaker 1: field theory by saying, oh, let's turn gravity into a
Speaker 1: quantum field theory, they go the other direction. They say,
Speaker 1: let's take space and make it into quantized units. Let's
Speaker 1: chop it up in the little bits and imagine that
Speaker 1: the quantized. So then as space is expanding, you're like
Speaker 1: popping off new little bits of space, which is sort
Speaker 1: of conceptually hard to imagine. But your question really was like,
Speaker 1: have we figured that out, could we possibly see it?
Speaker 1: And so far that the whole field is sort of
Speaker 1: in its infancy. You know, it's decades old. They only
Speaker 1: realized if you know, fifty years ago, was even possible,
Speaker 1: and how to do basic calculations and how to just
Speaker 1: get simple stuff right. Um, But the short answer is,
Speaker 1: and we could answer all these questions, we could resolve
Speaker 1: all these mysteries if we could see inside a black hole.
Speaker 1: You don't happen to have a black hole, dude, Uh,
Speaker 1: that's sort of impossable, right, Like you're not you're not
Speaker 1: getting information out of a black hole? Is that correct?
Speaker 1: That's exactly right. And that's the frustrating thing is that
Speaker 1: like gravity is very very weak, it's a very weak force.
Speaker 1: It takes a lot for gravity to do anything very powerful.
Speaker 1: But inside a black hole you have in tremendous gravity,
Speaker 1: so much gravity that it could reveal things like you know,
Speaker 1: the creation of new bits of space or the distortion
Speaker 1: of space, or it could show us like what's, um,
Speaker 1: what's the matter distribution like inside a black hole? Because
Speaker 1: general relativity says that there's a singularity, that there's all
Speaker 1: this mass concentrated in a single dot zero volume but
Speaker 1: if space is pixelated, if loop quantum gravity is right,
Speaker 1: then you can't have a tiny infinitesimal dot. You have
Speaker 1: need to have a basic unit of space. So if
Speaker 1: we could see what was going on inside a black hole,
Speaker 1: we could see what happens when gravity tries to compress
Speaker 1: things down to these tiny units of space. But you're right,
Speaker 1: all the secret to the universe exists inside black holes,
Speaker 1: but they are unobservable. Will never get that information and out,
Speaker 1: which is so frustrating. It's like if you know, the
Speaker 1: oracle says, here are all the answers, and I'm gonna
Speaker 1: put them in a box, which if you try to
Speaker 1: open it destroys all the answers. It's like some cruel
Speaker 1: Greek fable or something. You know. Also a really safe
Speaker 1: place to hide the secrets of the universe, right, that's right,
Speaker 1: and all your passwords. I keep all my passwords in
Speaker 1: a black hole. Just think. So the short answer is
Speaker 1: we're not anywhere close to discovering the basic pixels of space.
Speaker 1: But I think if you pulled physicists in them would
Speaker 1: say that space is probably pixelated. So I'm sorry if
Speaker 1: I if you already alluded to this and I missed it,
Speaker 1: But um, so would you say looking for pixelated space
Speaker 1: the smallest units of space is something that could potentially
Speaker 1: be done by experimental methods available to us if we had,
Speaker 1: you know, the ultimate particle collider or energy levels you
Speaker 1: know you couldn't that are nowhere near what we have today?
Speaker 1: Or is it just like not within reach of any
Speaker 1: reasonable experimental paradigm that we know about. That's a great question, um.
Speaker 1: And one of the amazing things about particle colliders is
Speaker 1: that there really is no limit to what they can do.
Speaker 1: It's really just a money question. Like the more money
Speaker 1: you give us, the bigger the particle collider we can build,
Speaker 1: the faster we can shoot those particles around. And speed
Speaker 1: is sort of inverse two distance, right, The faster your
Speaker 1: particles are going, the smaller the distance they can probe.
Speaker 1: And so there's really no limit. If we built a
Speaker 1: Milky Way size particle collider, then yes, we could answer
Speaker 1: these questions, and uh, you know, we could find space
Speaker 1: pixels and we could you know, see quantum effects at
Speaker 1: this level. Um, but you know that would cost us.
Speaker 1: I don't even know if there's a number for the
Speaker 1: amount of money. If so, be bigger than this recent
Speaker 1: stimulus by a lot. So you're saying it would not
Speaker 1: be like, you know, something five to ten times bigger
Speaker 1: than the large had round collider. It would need to
Speaker 1: be like galaxy sized or something. Yeah, it have to
Speaker 1: be like ten to the fifteen times larger than the
Speaker 1: larger run colider. And that would be like I don't
Speaker 1: even know what the acronym would be like, you can't
Speaker 1: just call it a large hage junk collider. You need
Speaker 1: like a very very very very very large hit junk
Speaker 1: lider V to the fifteen LHC or something. Nobody's even
Speaker 1: asking for that money. But yeah, there's no limit to
Speaker 1: to sort of how small we can peer down if
Speaker 1: we have really powerful colliders and we know the technology right, like, um,
Speaker 1: we just add more little boosters to make the particles
Speaker 1: go faster. Um. But you know, we also are working
Speaker 1: on other kinds of technologies to make these colliders more
Speaker 1: powerful without having to make them ridiculously big and expensive,
Speaker 1: because currently we're limited by sort of how fast we
Speaker 1: can make these particles move because it takes this these
Speaker 1: little units to give them a kick and then magnets
Speaker 1: to bend them. But if we can make those accelerators,
Speaker 1: the little units of accelerators, better and faster and more
Speaker 1: compact than we could build like tabletop accelerators. There are
Speaker 1: people here you see Irvine, working on these plasma wakefield
Speaker 1: devices to try to get particles accelerated to really high
Speaker 1: energies and very short distances um and then it might
Speaker 1: be possible to you know, peel back a layer of
Speaker 1: reality and see what's going on underneath the without spending
Speaker 1: ten of the fifteen trillion dollars. So we've been looking
Speaker 1: a lot at the very smallest properties of space. I say,
Speaker 1: we zoom out to the biggest possible, uh way of
Speaker 1: looking at space and talk about the shape of the
Speaker 1: universe we live in as a whole. Um. So, yeah,
Speaker 1: so you've I was reading an article that you and
Speaker 1: Jorge wrote about this. Uh could you talk a little
Speaker 1: bit about the shape of the universe. Yeah, the shape
Speaker 1: of the universe is a wonderful question. It's it's sort
Speaker 1: of hard to imagine because I think people again think
Speaker 1: about the shape of the universe, they think about like
Speaker 1: a big blob, and then when like, what is the
Speaker 1: shape of that blob? Is it, you know, look like
Speaker 1: a pile of dog poop or like a bagel, or
Speaker 1: like a doughnut or whatever. But when we talk about
Speaker 1: the shape of the universe again, we're talking about something intrinsic, right,
Speaker 1: We're talking about how do the pieces of the universe
Speaker 1: relate to each other? Because we don't imagine that the
Speaker 1: universe is like sitting in some larger space. We're not
Speaker 1: asking like, if you were outside the universe and looking
Speaker 1: at it, which shape would it have. We're really talking
Speaker 1: about how does the universe curve? You know, like when
Speaker 1: you put mass in a solar system, it bends space
Speaker 1: so that planets move in according to these geodesics, which
Speaker 1: happen to be orbits. So we're really talking about the
Speaker 1: large scale like bending of the universe. And you know,
Speaker 1: as you put stuff in the universe, planets, stars, whatever,
Speaker 1: the universe bends in such a way so that it
Speaker 1: would tend to collapse, right, tend things We tend to
Speaker 1: sort of roll towards each other, moved towards each other,
Speaker 1: so that gets space one curvature. But what we've done
Speaker 1: is we've we've gone out, we've measured the curvature of space.
Speaker 1: We've we've asked like how much stuff is there in space?
Speaker 1: And how do these things balance each other? Because it
Speaker 1: turns out there's a there's one way to bend the universe,
Speaker 1: and that's by having mass, and there are other ways
Speaker 1: to bend the universe the other direction. These things called
Speaker 1: dark energy, which are contributing to the expansion of space,
Speaker 1: actually has the opposite effect on this curvature. Some mass
Speaker 1: bends it one way, dark energy bends it the other way,
Speaker 1: and together the two things give you perfectly flat space.
Speaker 1: So these two titanic forces which are balancing each other
Speaker 1: and giving you space which is completely flat, meaning that
Speaker 1: on average there is no curvature to the universe. That
Speaker 1: that you know that things should move in straight lines.
Speaker 1: So I've read the curvature of the universe described alternately
Speaker 1: as flat and as almost flat. Could you help me
Speaker 1: sort sort out the difference? There is one of those
Speaker 1: just wrong or or what's going on? Well, it's a measurement, right,
Speaker 1: and we're measuring the curvature of the universe. And roughly
Speaker 1: how we do is we add up all these pieces
Speaker 1: and we ask, you know, what do they come out to?
Speaker 1: But they all have uncertainties, you know, we don't know
Speaker 1: precisely how much stuff there is in the universe. We
Speaker 1: don't know exactly how strong dark energy is. And we
Speaker 1: get better and better measurements every year, and those measurements
Speaker 1: are consistent with totally flat, right with adding up to
Speaker 1: being exactly flat. But there's uncertainty there, and some measurements
Speaker 1: suggest a tiny deviation from flat, and some measurements are
Speaker 1: consistent with flat and other things, and so there's some
Speaker 1: wiggle room there. And and we're trying to measure in
Speaker 1: lots of different ways because we don't just trust one
Speaker 1: experiment or one experiment or and so we try to
Speaker 1: probe these things from different directions and sometimes they slightly disagree,
Speaker 1: so there can be some sort of momentary controversy there.
Speaker 1: But you know, I think the larger question is like,
Speaker 1: why are we flat at all? You know, it seems
Speaker 1: sort of weird once you discover the space can be curved,
Speaker 1: to discover that our universe just sort of happens to
Speaker 1: be flat. So you say just sort of happens to
Speaker 1: be flat. That indicate that you think the flatness of
Speaker 1: the universe, in your expert opinion, is basically a coincidence,
Speaker 1: or do you think that that it's not a coincidence
Speaker 1: that it's a downstream effect of some thing we don't
Speaker 1: understand or some other variable. It depends right like um,
Speaker 1: before we had this theory for how the universe began,
Speaker 1: it seemed really weird to have a flat universe. Seemed
Speaker 1: really strange for space to be so smooth and to
Speaker 1: not have curvature, because as you put stuff in the universe,
Speaker 1: it should sort of gather together, right, that's gravity, and
Speaker 1: it should make it more and more curt and so
Speaker 1: it's it's weird to start with the universe that's pretty
Speaker 1: flat and then end up with the universe it's pretty flat,
Speaker 1: Like it doesn't seem stable. It seems like if you
Speaker 1: have any deviation from flatness, that deviation would build on
Speaker 1: itself and build on itself and build on itself, and
Speaker 1: eventually you'd be pretty far from flat. So then our
Speaker 1: universe is pretty old. It's fourteen billion years old. This
Speaker 1: has been going on for a long time. Why are
Speaker 1: we still flat? And so for a long time that
Speaker 1: was that seemed like a coincidence, like either we were
Speaker 1: so closed to flat in the first few seconds that
Speaker 1: we've hardly deviated it all, Like we're like balanced on
Speaker 1: the knife's edge and we're still balanced fourteen billion years later,
Speaker 1: which seems unlikely, or there's some reason for it. And
Speaker 1: the explanation that we've come up with recently is this
Speaker 1: idea of inflation, that the universe was stretched super quickly
Speaker 1: in the first few moments of the universe that made
Speaker 1: it essentially hyper hyper flat. It's like if you're standing
Speaker 1: on a tennis ball. You look around, and you can
Speaker 1: tell that the universe is a little bit curve, right,
Speaker 1: because the tennis ball is a lot of curvature to it.
Speaker 1: But if the tennis ball suddenly gets inflated to the
Speaker 1: size of a planet where you look around, you can't
Speaker 1: tell that the Earth is not flat, right, it seems
Speaker 1: to be flat. And so that's what happened, we think
Speaker 1: in the first few moments of the universe. That explains
Speaker 1: how the universe got so flat in the beginning. So
Speaker 1: if if this is what it is like in a
Speaker 1: flat universe, I mean, is there any way to to
Speaker 1: even discuss like what it would be like within a
Speaker 1: round universe or a square universe or anything other than
Speaker 1: a flat or almost flat universe. Yeah, Well, it has
Speaker 1: really fascinating applications for like the possible sizes of the universe. Right,
Speaker 1: if the universe is flat, then it can go on forever. Right,
Speaker 1: you can just keep going forever because it can be
Speaker 1: flat like an infinite sheet. Right, But in three dimensions,
Speaker 1: if the universe is curved, like if the universe is
Speaker 1: the surface of a sphere right in some higher dimensional space,
Speaker 1: then it it might not be infinite. Right. It might
Speaker 1: be that you move and you keep curving and eventually
Speaker 1: you come back to where you were, and so it
Speaker 1: could be infinite, but not necessarily have any edges, right
Speaker 1: because like on the surface of the sphere or on
Speaker 1: the surface of the Earth, you walk for long enough,
Speaker 1: you come back to where you started. You don't like
Speaker 1: run into the edge of the Earth. So the shape,
Speaker 1: this curvature of the universe has a lot of consequences
Speaker 1: for the potential size of the universe, And so if
Speaker 1: it was curved, it wouldn't necessarily be infinite. Um, if
Speaker 1: it's flat, that suggests it could be infinite, but it
Speaker 1: also might not be. Right, there's ways to connect the universe.
Speaker 1: It can be flat but also still be like weirdly
Speaker 1: connected like an asteroids game, so that you come off
Speaker 1: one side and you end up on the other side.
Speaker 1: Because remember space can have these complicated, non trivial connections
Speaker 1: between parts of it. The whole edge of the universe
Speaker 1: could be basically a set of wormholes that bring you
Speaker 1: back to the other side. All Right, we're gonna take
Speaker 1: one more break, but we'll be right back. All right,
Speaker 1: we're back. So I've got a question about the Big Bang. Then,
Speaker 1: with respect to the the expansion of the universe, we
Speaker 1: often hear, of course, the Big Bang was that the
Speaker 1: universe was once in this hot, dense state, and then
Speaker 1: there's this expansion. You you think, when you go through
Speaker 1: this period of inflation, that seems to be the consensus
Speaker 1: now and then we we keep expanding and cooling. But
Speaker 1: what form does that expansion take with respect to space?
Speaker 1: Does that mean that the universe or the contents of
Speaker 1: the universe expanded into pre existing space, or that space
Speaker 1: itself expanded, space itself expanded. The way I think about
Speaker 1: it's not like a small blob of stuff that then
Speaker 1: blew up and moved through space, but instead an infinite
Speaker 1: universe created with infinite stuff in it. And then the
Speaker 1: Big Bang happened simultaneously everywhere, all at once, meaning that
Speaker 1: all that stuff just got diluted, like new space was
Speaker 1: being created everywhere. Space was expanding, and it's not like
Speaker 1: it was stretching stuff into what was previously empty space.
Speaker 1: It was just creating new space everywhere between all the bits.
Speaker 1: So what used to be hot and dense and intense
Speaker 1: is now more dilute. And so I think one of
Speaker 1: the biggest misconceptions that the Big Bang started off like
Speaker 1: the whole universe the size of an atom, and then
Speaker 1: it's just a big explosion where stuff moves through space.
Speaker 1: But instead, I think it's much more natural to think
Speaker 1: about the universe be created um infinite amount of stuff
Speaker 1: created all at once, and then diluted and then expanded.
Speaker 1: So that's like requires you to imagine an infinite creation
Speaker 1: of stuff and then an infinite big bang on top
Speaker 1: of it, which is sort of mind blowing and also
Speaker 1: sort of more natural. I really like that explanation because
Speaker 1: I feel like it places uh sit places that the
Speaker 1: the individual thinker within the model, instead of placing us
Speaker 1: trying to place us with outside of the model, which
Speaker 1: which excuse this UH, this attempt to understand like what
Speaker 1: space is, you know, and then you don't have to
Speaker 1: ask questions like, well, where was the Big Bang? Was
Speaker 1: it over there and over there? And we're close to
Speaker 1: the center, and when we look around us, we see
Speaker 1: everything is moving away from us, and there's no directionality
Speaker 1: to it, like things over here moving away from us,
Speaker 1: things over there moving away from us. And that's true
Speaker 1: everywhere in the universe, which means that there is no center.
Speaker 1: There's no place from which this explosion happened. It happened
Speaker 1: everywhere all at once, and that's what differentiates sort of
Speaker 1: things moving through space from the expansion of space itself.
Speaker 1: This makes me wonder if, kind of like the idea
Speaker 1: of bending in general relativity, if we're suffering from the
Speaker 1: connotation ends of the word we happen to use. The
Speaker 1: idea of expanding usually indicates like the pushing of boundaries
Speaker 1: into areas that were previously out of bounds, Like if
Speaker 1: you expand a map, you know you're pushing the edges out,
Speaker 1: But that doesn't really make sense in this case. We're
Speaker 1: talking about the expansion of space, So it would almost
Speaker 1: make more sense to think about the Big Bang maybe
Speaker 1: as a um a population of or I don't know,
Speaker 1: a population of space expanding and infilling of space. Yeah.
Speaker 1: I think of it like a take an infinite ruler,
Speaker 1: right and mark off two dots, and then somebody stretches it. Right. Well,
Speaker 1: it was infinite before, it's infinite now. But there's more
Speaker 1: of it, right, And so space is really this like
Speaker 1: it's it's it's more of a stretching, you know, than
Speaker 1: an expansion. It's not an explosion. It's more of like
Speaker 1: a Yeah, it's like a stretching. There has to be
Speaker 1: a social distancing metaphor, and all of us I keep,
Speaker 1: I keep kind of grasping for it. Well, I'm certainly
Speaker 1: expanding inside my pants on a notice that they're all there.
Speaker 1: They're all denser these days, and then before this quarantine.
Speaker 1: But I think that's something that's hard to grapple with,
Speaker 1: is this creation of an infinite universe or an infinite
Speaker 1: amount of space. And people write us questions in our
Speaker 1: podcast all the time, and one of the most common
Speaker 1: questions is what is the universe expanding into? Right? And
Speaker 1: I think that comes from this conception of the Big
Speaker 1: Bang as a small dot which is then exploding, right,
Speaker 1: or even if you imagine space as a chunk of
Speaker 1: stuff and you understand the space itself is expanding, you
Speaker 1: wonder what is it expanding into? And I think that's
Speaker 1: this desperation to sort of place the universe in a
Speaker 1: context is to say, alright, we started off by drawing
Speaker 1: access lines and describing all the stuff happening in universe
Speaker 1: in this sort of construct we imagine called space, which
Speaker 1: was maybe philosophical or just a thought idea, and then
Speaker 1: it turns out it's real. Well, we'd like to place
Speaker 1: then that space in some sort of super space or
Speaker 1: meta space. So sort of grapple with it. It's difficult
Speaker 1: even for me or for cosmologists, I think, to still,
Speaker 1: you know, grapple with this concept of space not being
Speaker 1: in anything else, not necessarily sitting in a superspace or
Speaker 1: a meta space on which you can define these axes.
Speaker 1: It just sort of is inherent. So I'm sure you've
Speaker 1: gotten this question before, but I think it always helps
Speaker 1: to to try as best we can to imagine it
Speaker 1: on our own level. So imagine you have a space ship,
Speaker 1: you know, that can go faster than the light, as
Speaker 1: fast as you possibly wanted to go, there's no limit
Speaker 1: to it, and you just travel in the same direction
Speaker 1: forever but what do you imagine happens then, Well, I
Speaker 1: think you would really never get anywhere. I mean, you
Speaker 1: leave the galaxy, and then you leave the local group
Speaker 1: of galaxies, and then you're flying off towards another group
Speaker 1: of galaxies. But that group of galaxies is moving away
Speaker 1: from us faster than the speed of light. Right now.
Speaker 1: It's not again physics lawyer talk, it's not moving through
Speaker 1: space fasten the speed of light. New space is being
Speaker 1: created between us and those galaxies faster than we could
Speaker 1: move to it, faster than even a photon could fly
Speaker 1: through it. So those galaxies, if you just sat here
Speaker 1: on Earth, those galaxies are disappearing from our view. Eventually,
Speaker 1: the photons being created by them will no longer get
Speaker 1: to us. It's like if Lussin Bolt was running at you,
Speaker 1: but somebody was laying track in front of him faster
Speaker 1: than he was running. It doesn't matter how fast he is,
Speaker 1: right if they're laying track faster, he's never going to
Speaker 1: beat them. So, in that same way, those photons will
Speaker 1: never get to us, and we will never get to
Speaker 1: those galaxies, which means that the night sky is getting
Speaker 1: darker and darker. Right things are literally falling off the
Speaker 1: edge of the observable universe, and things are disappearing from
Speaker 1: our view. You know, in fifty billion years or a
Speaker 1: hundred billion years, it may be that there are no
Speaker 1: galaxies visible in the sky. Imagine human civilization survives that long,
Speaker 1: or maybe we have some apocalypse when we rebuild and
Speaker 1: we start building human edge again, then there is no
Speaker 1: Edwin Hubble moment when you look out in the sky
Speaker 1: and discover distant galaxies and realize, oh, we're not alone
Speaker 1: in the universe is expanding. They would never know that.
Speaker 1: There would be no way for them to learn that,
Speaker 1: and that to me is so tantalizing and frustrating to
Speaker 1: know that that knowledge could be hidden, because I project
Speaker 1: the other way. I'm like, all right, well, we're fourteen
Speaker 1: billion years into the universe. What has already disappeared from
Speaker 1: the night sky which we will never recover? What clues,
Speaker 1: what incredible context are we missing about the night sky
Speaker 1: that you know, astronomers thirteen billion years ago would laugh
Speaker 1: at us for not understanding. We don't know, and we
Speaker 1: probably never will, and that drives me crazy. So this
Speaker 1: is our shot. We don't have time to re evolve
Speaker 1: from bacteria and do it again. That's right, that's right.
Speaker 1: If we haven't missed our shot already, we should scrape
Speaker 1: the bottom of the barrel and understand what's going on
Speaker 1: out there in the universe. You know, we wrote a
Speaker 1: whole book about it's called We Have No Idea, And
Speaker 1: the point of that book is that we don't even
Speaker 1: really know what the denominator is on our ignorance, Like
Speaker 1: what fraction of the universe do we have understood? You know,
Speaker 1: given the fact that we only in the last thirty
Speaker 1: years figured out that space is a thing and it's
Speaker 1: expanding and could do all these weird stuff, and the
Speaker 1: universe is growing and growing, that so many of our
Speaker 1: basic questions about the universe have different answers than we imagined,
Speaker 1: And we're discovering new basic questions like what is space?
Speaker 1: What is time? How many dimensions are there to space,
Speaker 1: which we didn't even get into. Um. It tells me
Speaker 1: that there's a lot of stuff that we don't even
Speaker 1: know to ask yet. And I would just hope we
Speaker 1: figure out where the questions are before we run out
Speaker 1: of time to answer them. So I've got a question
Speaker 1: going in another direction. This might not make any sense,
Speaker 1: Feel free to decline it if it doesn't. But I
Speaker 1: was wondering, does it make sense to think that the
Speaker 1: fundamental properties of physics are actually properties of space, you know,
Speaker 1: or of local space as we know it. I'm thinking about,
Speaker 1: for example, you know, I don't know relative strength of
Speaker 1: fundamental forces or the mass of the proton or something.
Speaker 1: Does the nature of space have anything to do with
Speaker 1: these constants or the laws of physics? And are they
Speaker 1: in some way contingent upon what kind of space we
Speaker 1: live in? Oh? My god. Absolutely, that's not a crazy idea.
Speaker 1: I mean, it is a crazy idea, but it's also real,
Speaker 1: Like the universe is a crazy idea. So um, A
Speaker 1: lot of the things that we consider to be fundamental
Speaker 1: about the universe are actually just properties of space and
Speaker 1: the way that space around here at least seems to behave.
Speaker 1: For example, we know that particles. The reason particles have mass,
Speaker 1: tiny little particles like electrons have mass, it's not because
Speaker 1: they have a little stuff to them. It's because they
Speaker 1: interact with this new field we discovered, the Higgs field,
Speaker 1: and it's in interacting with those fields that they get inertia.
Speaker 1: The reason a little electron when you push it it
Speaker 1: um takes some force to get it to move, is
Speaker 1: because it has some inertition. The inertia comes from the
Speaker 1: Higgs field. But where does the Higgs field come from? Well,
Speaker 1: the Higgs fields we talked about before is one of
Speaker 1: these quantum fields. It's part of space, and it's got
Speaker 1: some tension built into it. Like when the universe cooled
Speaker 1: in the very first few moments, there's a lot of
Speaker 1: energy in the universe sort of cooled down, cooled down,
Speaker 1: But the Higgs field got stuck. It didn't go all
Speaker 1: the way down to zero, got like stuck on a
Speaker 1: little shelf, and it's very happy there for now. But
Speaker 1: if the Higgs field got kicked off that shelf and
Speaker 1: relaxed down to a lower level, then the electron would
Speaker 1: have less mass or zero mass, the proton, the corks
Speaker 1: would have less mass or zero mass. All the fundamental
Speaker 1: particles could have different masses, and that includes the force
Speaker 1: carrying particles like the W and the z boson, which
Speaker 1: affect the strength of the forces. So like the reason
Speaker 1: the weak force is so weak is because the W
Speaker 1: N Z boson that carry it are so heavy. Because
Speaker 1: the Higgs field is stuck where it is, so everything
Speaker 1: is hanging on the Higgs field, being stuck on this shelf,
Speaker 1: and if it gets down to a different shelf or
Speaker 1: falls off completely, space is totally different. I mean, it
Speaker 1: still follows laws of physics, but the laws of is
Speaker 1: if we've discovered a sort of emergent properties of all
Speaker 1: these assumptions, and if both changed, everything would be different
Speaker 1: and space would be almost unrecognizable. So yeah, crazy, but
Speaker 1: also true, and it's possible that that could happen. You know,
Speaker 1: we don't know what it takes to trigger the Higgs
Speaker 1: field to sort of collapse to what we call its
Speaker 1: true vacuum. Some people worry that, for example, collisions of
Speaker 1: particles that high energies lack are being done by some
Speaker 1: people in Switzerland, you know, not now actually during this pandemic.
Speaker 1: But those kind of situations could create um vacuum bubbles
Speaker 1: of the Higgs field, and those vacuum bubbles would expand
Speaker 1: at the speed of light and pass through all space,
Speaker 1: and so we could end up collapsing the Higgs vacuum
Speaker 1: and changing the way space works, and you would still
Speaker 1: have physics. You would just have very very different physics
Speaker 1: that we would you know, we wouldn't be around to
Speaker 1: explore it. But somebody would have a lot of fun
Speaker 1: figuring out what the rules of that space are. I
Speaker 1: think there's there's another fascinating as it's of space, which
Speaker 1: is sort of hard to grapple with. Which is so
Speaker 1: the relationship between space and stuff, Like we think about
Speaker 1: stuff as in space. It's like moving through space. Spaces
Speaker 1: like there for you to be in, like the way
Speaker 1: a car is on a road. Right, But if you
Speaker 1: are serious about space having quantum fields in it, and
Speaker 1: all particles are just excitations of those quantum fields, then
Speaker 1: stuff is really just a property of space, right, Like
Speaker 1: if space is just like a big quantum field, then
Speaker 1: you know, you imagine your road is like a bigger
Speaker 1: rubber band, and a car on the road is like, okay,
Speaker 1: this part of the rubber band is bouncing, has it's excited,
Speaker 1: and then as the car moves down the road, it's
Speaker 1: not like you move that car. Instead, that energy gets
Speaker 1: transported to a new part of space, which then has
Speaker 1: the bounces. So it's like every time you move from
Speaker 1: one piece of space to another, it's like star Trek teleporter.
Speaker 1: It's not actually the same particles, right, It's like the
Speaker 1: information is being transmitted, so you can excite that new
Speaker 1: bit of space in the same way. But is it
Speaker 1: at least still you you know, it's all ship of
Speaker 1: theses stuff. And so when I slide from over here
Speaker 1: over here with the space isn't changing. It's just like
Speaker 1: different parts of space are getting excited and so, and
Speaker 1: that's the way. We are all sort of part of space.
Speaker 1: We're not in it, we are part of it. This
Speaker 1: almost seems like a sort of deeper reformulation of the
Speaker 1: ether idea, right, like that they used to think that
Speaker 1: there needed to be a uh, substance in space that
Speaker 1: electromagnetic radiation would propagate through, and then that was considered obsolete.
Speaker 1: But maybe is space itself in a way that substance
Speaker 1: that everything propagates through. Yeah, yeah, I mean that we're
Speaker 1: discovering all sorts of new forms of ether, like dark
Speaker 1: energy and a cosmological constant in the Higgs field, and
Speaker 1: like there are these things that that fill the universe
Speaker 1: with stuff with with something with some physical dynamical object
Speaker 1: and so, right, it used to be ridiculous to imagine
Speaker 1: that space was filled with something, and now it turns
Speaker 1: out space is everything, right cool, um, it is it
Speaker 1: is very cool. Alright. So we talked about several other
Speaker 1: properties of space, but one that we're wondering about now
Speaker 1: is how many ways does it go? You know, so
Speaker 1: you gotta got up and down, left, right, back and forth.
Speaker 1: And we know that. Uh. Now, we generally think of
Speaker 1: time as another dimension of space. Space time that they're
Speaker 1: they're sort of combined there. But does it stop there
Speaker 1: or is it reasonable to think about additional directions that
Speaker 1: you could go in that are not even conceivable to
Speaker 1: us in our you know, macroscopic movements. I think what
Speaker 1: physics has taught us over the last time of years
Speaker 1: is that every crazy idea is reasonable to think about
Speaker 1: for a few moments, and some of them will turn
Speaker 1: out to be true. And this is one of my
Speaker 1: favorite questions, is like how many dimensions are there to space?
Speaker 1: And I think you can start from just like, well,
Speaker 1: why would there be three? You know, like three is
Speaker 1: a weird number. You know, it's uh, whenever you find
Speaker 1: something about the universe and has a number, and you've
Speaker 1: got to ask, like why that number? If you ask,
Speaker 1: like mathematicians, what like deep numbers do you expect to
Speaker 1: see in a description of the universe? You know, they'll
Speaker 1: say one or pie or e, but nobody says three,
Speaker 1: right unless they're Catholic and think that the trinity has
Speaker 1: really insight into the fundamental nature of reality. And hey,
Speaker 1: you know, maybe they're right. But that's like clue number one.
Speaker 1: It's like, is there something three ish about the universe?
Speaker 1: Like that's kind of weird, but maybe it is. But
Speaker 1: it turns out that there's no reason to think that
Speaker 1: the universe couldn't have more dimensions. And you know what
Speaker 1: that would mean is like another way to move, Like
Speaker 1: you write your position in spaces, you know x y Z, right,
Speaker 1: you would just have another coordinate system. And the first
Speaker 1: thought you might have is like, well where would it go? Right,
Speaker 1: Like where do you put it? You can't, like X
Speaker 1: y Z seems to describe everything. Where would it be?
Speaker 1: And you have to it's really hard to think it
Speaker 1: higher dimensions. So you have to do this trick where
Speaker 1: you think in two D and extrapolate the three D
Speaker 1: because your mind can handle both of them, and then
Speaker 1: try to use that three D that extrapolation to go
Speaker 1: from three to four. Right, So when you think about
Speaker 1: two D, you like on the surface of a piece
Speaker 1: of paper, three D you're like a cube. So imagine
Speaker 1: moving that piece of paper through three dimensional space and
Speaker 1: thinking about what that would be like as you like
Speaker 1: interact with the three D objects. A sphere passing through
Speaker 1: a piece of paper would look like a dot that
Speaker 1: grows to a circle and then shrinks again to a
Speaker 1: dot and disappears. So in that same way, you can
Speaker 1: imagine four D objects in three D space. And so
Speaker 1: you use that sort of mental exercise to imagine like
Speaker 1: what these other dimensions could be like. And but it
Speaker 1: turns out that that the current theories of physics don't
Speaker 1: imagine these other dimensions being like these first three that
Speaker 1: wouldn't be infinite dimensions that you could go like there's
Speaker 1: no limit to how far you can go and X
Speaker 1: or y or z. But these other dimensions, if they
Speaker 1: were infinite, we probably would have noticed them already. So
Speaker 1: if they exist, they would be compactified. They would be
Speaker 1: like rolled up like instead of being infinite, there would
Speaker 1: be curved like we talked about before, and they might
Speaker 1: just be like a centimeter wide, and you know what
Speaker 1: that means. It's like, Okay, you have x, y, z,
Speaker 1: and then you have another number which varies between you know,
Speaker 1: zero and one centimeter, And it's actually quite a natural idea.
Speaker 1: If it's true, it would explain a lot of mysteries
Speaker 1: of the universe. Like in the in the nineties, I
Speaker 1: remember when this happened, people came up with this idea
Speaker 1: that we might have um extra dimensions of space of
Speaker 1: time to explain why gravity is so weak. Like you
Speaker 1: know that we have these basic forces of the universe,
Speaker 1: the electromagnetic force, the weak force, the strong force. They're
Speaker 1: all pretty powerful compared to gravity. Gravity is like ten
Speaker 1: to the thirty times weaker in comparison. And that's weird.
Speaker 1: Why can't we jump at all? And and that's weird right,
Speaker 1: Like if you hold a little magnet above the Earth,
Speaker 1: you have the entire gravitational force of the Earth, right
Speaker 1: is being outpowered by a tiny little fridge magnet. Right,
Speaker 1: it's pretty impressive. Um, so we wonder like why is
Speaker 1: gravity is so weak? And then we thought, well, maybe
Speaker 1: gravity isn't actually so weak. It's just that most of
Speaker 1: gravity sort of leaking out into these other dimensions because
Speaker 1: the strength of gravity depends on how many dimensions there are.
Speaker 1: Like you know, as space grows, as you get further
Speaker 1: away from something the sort of same amount of gravitational
Speaker 1: power spreads out through that dimensional space. So space was
Speaker 1: four or five or six dimensional, gravity would be weaker, right,
Speaker 1: And so they imagine that maybe space does have more
Speaker 1: dimensions and that gravity is actually really strong, and these
Speaker 1: dimensions are really really short and anywhere past like a
Speaker 1: centimeter distant, what you're feeling is gravity being weakened because
Speaker 1: it's spread out in these other dimensions. So that was
Speaker 1: the idea. It's sort of cool insight. I love when
Speaker 1: you have like an idea that requires you to revolutionize
Speaker 1: the way you think about the universe and solves an
Speaker 1: existing puzzle. Um that was the idea, and it was
Speaker 1: especially tantalizing because they realized nobody had checked, like what
Speaker 1: is the gravitational force between two things that are just
Speaker 1: a centimeter apart? And they realized, oh my gosh, nobody's
Speaker 1: actually done that experiment. We didn't even know. And the
Speaker 1: reason is that it's hard, like what's the gravitational force
Speaker 1: between two marbles? Almost nothing, So it takes like real
Speaker 1: experimental bravado to set up the test to test gravity
Speaker 1: really really short distances. And so they did that, and
Speaker 1: they've done a bunch of these cool experiments in the
Speaker 1: University of Washington testing really really isolated situations, and they
Speaker 1: found that gravity doesn't seem to get any stronger as
Speaker 1: you bring things really really close together. And then we
Speaker 1: tried to discover these extra dimensions at the particle colliders,
Speaker 1: of course, because we use particle colliders for everything, you know,
Speaker 1: test the fundamental theories of the universe and new new
Speaker 1: new dimensions and you know, clean your laundry and all
Speaker 1: sorts of stuff. And the idea is that if gravity
Speaker 1: gets really strong when things get closed up, then maybe
Speaker 1: when proton get smashed together, you could create little mini
Speaker 1: black holes. Because if gravity is really powerful as short distances,
Speaker 1: then even the really low mass stuff like protons might
Speaker 1: have enough energy to create black holes. And that's what
Speaker 1: you know, there's a whole hull baloo about whether or
Speaker 1: not the particle collider was going to destroy the world. Um,
Speaker 1: and that's one reason why people thought maybe it could happen,
Speaker 1: is that we might create these black holes, which would
Speaker 1: prove that there are extra dimensions and explain why gravity
Speaker 1: is so weak, and then also you know, eat the
Speaker 1: Earth and end the human race. But it turns out
Speaker 1: that we haven't seen any of those black holes. And
Speaker 1: also we're pretty confident that that we're not going to
Speaker 1: be creating a dangerous black holes. That's certain because there
Speaker 1: are other collisions that happen all the time, very high
Speaker 1: energy collisions from space that create the same configurations and
Speaker 1: haven't yet created a black hole to eat the Earth.
Speaker 1: So we thought that was safe. But we didn't see
Speaker 1: these black holes, which would have proven to us that
Speaker 1: there were extra dimensions, and so currently we don't know
Speaker 1: if there are other dimensions to space like we think
Speaker 1: there might be. It still could be possible. They would
Speaker 1: just have to be smaller than about a millimeter, but
Speaker 1: we haven't seen them and we don't have any evidence
Speaker 1: that they exist. But there are some theories that like them,
Speaker 1: like Strength theory would love if there were eleven or
Speaker 1: twenty six dimensions, but at this point we sort of
Speaker 1: haven't seen them until we build that you know, trillion
Speaker 1: dollar galaxy sized particle collider. Well, it looks like we're
Speaker 1: running out of time here, Daniel. You're you and Jore
Speaker 1: are still actively putting out episodes of the podcast. Can
Speaker 1: you give us just a brief idea of like what
Speaker 1: is out right now and what's coming out in the
Speaker 1: immediate future. Yeah, we're putting out episodes of Daniel and
Speaker 1: Jorge Explain the Universe twice a week. Recent topics include
Speaker 1: like could dark matter be made out of quarks? Or
Speaker 1: what's the cosmological constant? Or We've been doing a really
Speaker 1: fun series on analyzing the science of science fiction universes
Speaker 1: where we interview famous science fiction authors and ask them
Speaker 1: nitpicky physics questions about their wormholes and their warp drives.
Speaker 1: So we're having a lot of fun and we answer
Speaker 1: a lot of listener emails. We had a whole episode
Speaker 1: recently where we just went through listener questions and answered
Speaker 1: all of their questions from seven year olds to seventy
Speaker 1: seven year olds. Sorry, I just had a glance at
Speaker 1: the I was glanced into the episode list to see
Speaker 1: if I was particularly familiar with any of the authors.
Speaker 1: So that you've you've talked to thus far y'all doing? Uh,
Speaker 1: Kim Stanley Robinson by by chance? No, we have it yet,
Speaker 1: but we've talked to Bray Crouch. Should we talk to
Speaker 1: Hugh Award winning authors like Ann Lecky and Mary Robin
Speaker 1: and Cole and Becky Chambers um, it's been really fascinating
Speaker 1: to see, like, how do you build the science fiction universe?
Speaker 1: At what point do you stop worrying about getting the
Speaker 1: science right and just think about the story. And then also,
Speaker 1: for me, since I'm such a science fiction buff, I
Speaker 1: just get a fanboy a little bit and talk to
Speaker 1: all these famous people. This might be too loaded of
Speaker 1: a question, but if you could interview a now deceased
Speaker 1: science fiction author and asked them some of these same questions,
Speaker 1: which one would you choose? You know, until I learned
Speaker 1: that he was also a jerk, I would have loved
Speaker 1: to interview Isaac Asimov because he created not just you know,
Speaker 1: new technology fiction, but like his Foundation series where he
Speaker 1: creates like actually a new field of science in his
Speaker 1: prediction of the future. Um, I thought that was really fascinating.
Speaker 1: I would love to just understand the kind of development
Speaker 1: of that idea and how he built a story around it.
Speaker 1: But then it turns out, like many greats from the past,
Speaker 1: he was also a jerk to lots of people he
Speaker 1: worked with. All right, well, well, thanks again for for
Speaker 1: coming on the show and chatting with us, And yeah,
Speaker 1: we encourage our listeners to check out those episodes and
Speaker 1: uh you know, and and hang with us. Thanks for
Speaker 1: calling in from your closet to talk with us. As
Speaker 1: we call in from our closets, don't expand out of
Speaker 1: reach before the next time we get to have you on.
Speaker 1: I hope I'll still fit in my pants by the
Speaker 1: next time I talk to you, guys. Thanks very much
Speaker 1: for having me on. All right, thank you, Thanks Daniel.
Speaker 1: In the meantime, if you want to check out other
Speaker 1: episodes of Stuff to Boil your Mind, head over to
Speaker 1: stuff to Boil your Mind dot com. That'll shoot you
Speaker 1: over to the I Heart listing for this show. But
Speaker 1: ultimately you can find our podcast wherever you get your
Speaker 1: podcasts and wherever that happens to be. Just make sure
Speaker 1: you rate, review, and subscribe huge thanks as always to
Speaker 1: our excellent audio producer Seth Nicholas Johnson. If you would
Speaker 1: like to get in touch with us with feedback on
Speaker 1: this episode or any other, to suggest a topic for
Speaker 1: the future, or just to say hi, you can email
Speaker 1: us at contact at stuff to Blow your Mind dot com.
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