Speaker 1: Hey, Hey, how are the mountains in Panama?
Speaker 2: They are wet and hot and beautiful.
Speaker 1: Wet and hot in the best possible way.
Speaker 2: That's right, the safest for work sounds plasma?
Speaker 1: Are they like tall mountains? Is Panama famous for having
Speaker 1: tall mountains?
Speaker 3: Uh?
Speaker 2: Sort of. We're a pretty small country, but there is
Speaker 2: a pretty large volcano there. It's about twelve thousand feet.
Speaker 1: Oh wow, that sounds pretty impressive coming from like the
Speaker 1: Danish point of view.
Speaker 2: Are you from Denmark?
Speaker 1: My wife's family is from Denmark and we all speak Danish.
Speaker 2: And do they have mountains there?
Speaker 1: You know? They think they have mountains. But the highest
Speaker 1: point in Denmark is like five hundred feet above sea level, But.
Speaker 2: The rest of the country is like two thousand feet
Speaker 2: below sea level, isn't it. So it's a pretty big
Speaker 2: mountain relatively.
Speaker 1: No, that's the Netherlands. Denmark is mostly above sea level,
Speaker 1: oh right, which makes it very flat and very nice
Speaker 1: to ride bikes around.
Speaker 2: What's the biggest mountain in Denmark?
Speaker 1: They call it Himmelbeard, which literally means the mountain of Heaven.
Speaker 2: WHOA, how big is it?
Speaker 1: It's like five hundred feet above sea level?
Speaker 2: I think the hill I live on is bigger than
Speaker 2: five hundred feet? Does I mean I live in heaven?
Speaker 1: You live in Danish Heaven.
Speaker 2: I live in California Heaven Valhalla. I am Horhembi cartoonists
Speaker 2: and the author of Oliver's Great Big Universe.
Speaker 1: Hi. I'm Daniel. I'm a particle physicist and a professor
Speaker 1: at UC Irvine, and I love mountains in the summer.
Speaker 2: Oh not in the spring or fall.
Speaker 1: Definitely not in the winter. Spring and fall can be acceptable.
Speaker 2: Now do you like to look at mountains? Do you
Speaker 2: like to climb mountains? Do you like to dig under mountains?
Speaker 2: How do you like to position yourself relative to a
Speaker 2: large rock?
Speaker 1: I like to be in the mountains in the summer.
Speaker 1: It's beautiful and the fresh air and hiking and the
Speaker 1: views and all that stuff. In the winter, I prefer
Speaker 1: to be far away from the mountains, though I do
Speaker 1: enjoy looking at them, you know, out of the window
Speaker 1: of an airplane.
Speaker 2: But doesn't that require you to get out of your couch?
Speaker 2: Isn't that the problem here?
Speaker 1: I have no problems getting off my couch in the summer.
Speaker 1: I love going to Aspen, and I love the Rockies.
Speaker 1: But man, in the winter that is just not fit
Speaker 1: for human habitation.
Speaker 2: I see, so nine months a year we can find
Speaker 2: you in a couch. Three months a year you're open
Speaker 2: a mountain.
Speaker 1: It's a pretty good life. That's my personal valhalla.
Speaker 2: That's right, it's called tenure. You just disappear into a mountain.
Speaker 1: When you get ten year in the University of California,
Speaker 1: they actually give you a couch, not a mountain. Not
Speaker 1: a mountain. No, there's a lot more couches to go
Speaker 1: around than mountains.
Speaker 2: Just a mountain of paperwork. But anyways, welcome to our podcast,
Speaker 2: Daniel and Jorge Explain the Universe, a production of iHeart Radio.
Speaker 1: In which we climb the mountain of mysteries that we
Speaker 1: have about the way the universe works. We want to
Speaker 1: take everything apart and understand how it all interacts, how
Speaker 1: those little particles push and pull on each other, how
Speaker 1: they dance together to make the reality that we're aware of,
Speaker 1: and how they build themselves up into mountains and planets
Speaker 1: and solar systems and galaxies and the entire universe that
Speaker 1: we one day hope to understand and explain to you.
Speaker 2: That's right. We stand on the shoulders of giants to
Speaker 2: get a better view of the entire cosmos, hopefully getting
Speaker 2: a little bit closer to the stars and what makes
Speaker 2: them turn, what makes them shine, what makes them explode,
Speaker 2: and what will happen to them in the far off future.
Speaker 1: One of the most incredible things about physics is that
Speaker 1: those questions about the stars and the questions under our
Speaker 1: feet can often be very closely related. They might even
Speaker 1: be the same. The same laws of physics that tell
Speaker 1: us how the stars move and how they orbit each
Speaker 1: other and how the universe develops should be applicable to
Speaker 1: the rocks and the bananas and the white chocolate and
Speaker 1: everything else that we find around.
Speaker 2: Us, Especially if you live on the side. That would
Speaker 2: be the same physics, right.
Speaker 1: That's right. Solar Newton probably had that realization a lot
Speaker 1: earlier than ours.
Speaker 2: Yeah, yeah, he was probably sweating the details of living
Speaker 2: on the Sun.
Speaker 1: My favorite model of how the Sun works is actually
Speaker 1: Gary Larson's model.
Speaker 2: Oh yeah, what did he say about the Sun?
Speaker 1: Well, he has this awesome far side cartoon where it's
Speaker 1: just like a sweaty guy inside the Sun and he's
Speaker 1: got a big lever that says rise or set.
Speaker 2: I think he had the green biology, not astrophysics.
Speaker 1: No, obviously that makes no sense because if you're inside
Speaker 1: the sun, what do you do to rise and set? Right?
Speaker 2: That's your quibble with the cartoon, is like the direction
Speaker 2: of up and down, not the person living inside the
Speaker 2: sun pulling a lever.
Speaker 1: No, you'd need one lever for every planet. Right, how
Speaker 1: do you rise over Jupiter and set over the Moon?
Speaker 1: And yes, that's my quibble with the science of the
Speaker 1: far side.
Speaker 2: Maybe he was pulling the Earth lever.
Speaker 1: I think there's a lot going on in that cartoon.
Speaker 1: At the same time, it's God layers.
Speaker 2: But speaking of layers, there are many layers to the Earth.
Speaker 2: Some of them go pretty high, which gives us a
Speaker 2: view of everything that surrounds us and makes us all
Speaker 2: ask questions about how things work in the universe.
Speaker 1: It's just part of being a curious human in the
Speaker 1: world to wonder how everything works, to look for explanations,
Speaker 1: to try to tell stories about the universe that makes
Speaker 1: sense to us. That's what we try to do with
Speaker 1: the cutting edge of science. That's what we do here
Speaker 1: on the podcast, and that's what we want you to
Speaker 1: do when you are going about your lives. I want
Speaker 1: you all to think like physicists and wonder how does
Speaker 1: that work work? Do I really understand how these two
Speaker 1: ideas come together?
Speaker 2: And do I really want to climb that mountain in
Speaker 2: the winter?
Speaker 1: No, No, I want to take a helicopter to the top.
Speaker 1: That's what I want.
Speaker 2: I do. Like mountains in the winter, that's the one
Speaker 2: you can ski and snowboard.
Speaker 1: You see that, Like those are good things I don't understand. Yeah,
Speaker 1: you're super fun.
Speaker 2: What's not to like about strapping some planks on your
Speaker 2: feet and then jumping down a mountain?
Speaker 1: Yeah, it's cold, it's expensive, it's dangerous. What couldn't you love?
Speaker 2: The thrill, the fun, the outdoor activity of it.
Speaker 1: I get that on the four or five every day
Speaker 1: around here.
Speaker 2: Well there you go. Should just take the four or
Speaker 2: five to the top of the mountain. But anyways, people
Speaker 2: do have questions. We all have questions about the universe,
Speaker 2: about how things work around us, and sometimes we answer
Speaker 2: those questions on this podcast.
Speaker 1: We encourage you to think deeply about the nature of
Speaker 1: the universe and to write to us when you are
Speaker 1: confused or you want inside. We answer all of our
Speaker 1: listener emails. Please send your questions to Questions at Danielanjorge
Speaker 1: dot com.
Speaker 2: So today on the podcast we'll be tackling listener questions
Speaker 2: number forty six, Couch Surfing Edition.
Speaker 1: I'm pretty sure nobody who's asking these questions has visited
Speaker 1: the Sun.
Speaker 2: For example, Well, how do you know, Daniel? Do you
Speaker 2: know all of our listeners? I don't know all of
Speaker 2: our listeners and their travel experiences.
Speaker 1: But I know that nobody has visited the Sun, So
Speaker 1: that rules out everybody, including our listeners.
Speaker 2: How do you know, Daniel? Or how do you know
Speaker 2: there aren't any aliens listening to the podcast?
Speaker 4: Oh?
Speaker 1: Are we doing that kind of podcast today? Dream skettic condition?
Speaker 1: How do you know, Daniel? How do you know? How
Speaker 1: do you know I'm even Daniel today? If you're going
Speaker 1: to be really scotch.
Speaker 2: That's right. How do I know you're not the alien?
Speaker 1: Hmmm? Or I could be my brother Chimoon and you
Speaker 1: know that my mother can't tell us apart on the
Speaker 1: phone still after fifty years.
Speaker 2: Oh boy, are we getting into the dynamics of you
Speaker 2: and your brother again?
Speaker 1: Let's answer some listener questions.
Speaker 2: Yes, let's get back on track here. Our listeners have
Speaker 2: questions and sometimes we answer them here on the podcast,
Speaker 2: and today we have three pretty awesome questions. One of
Speaker 2: them is about the biggest mountain possible, the other one
Speaker 2: is about the Higgs field, and the third one is
Speaker 2: about time and can it go faster or slower depending
Speaker 2: on where you are. So let's jump right in. Our
Speaker 2: first question comes from Nicholas.
Speaker 3: Hello, gentlemen, this is Nicholas from Sweden. Is there a
Speaker 3: limit on how high a mountain can be come on Earth?
Speaker 3: Before Phystix limits it? When the base of the mountain
Speaker 3: grow larger and larger, does the curvature of the Earth
Speaker 3: affects the height?
Speaker 1: Mm?
Speaker 2: Awesome question from Nicholas. Now do you think Nicholas knows
Speaker 2: the difference of where Vikings come from in Scandinavia?
Speaker 1: I'm pretty sure Nicholas has a good grasp on his
Speaker 1: own history. I guess.
Speaker 2: Did the Swedish countess Vikings? I think I've been there
Speaker 2: and I think I did see a Viking ship there right.
Speaker 1: Yes, the Danes, the Swedes, and the Norwegians all have
Speaker 1: Viking ancestry. The Fins are different. They're Nordic but not Scandinavian.
Speaker 2: But did they have Vikings too?
Speaker 1: I mean, I'm sure some people who live in Finland
Speaker 1: today have Viking ancestry the way people who live in
Speaker 1: like Sardinia have Viking ancestry because the Vikings went everywhere
Speaker 1: and did horrible things to local people. But the Viking
Speaker 1: culture itself is more Scandinavian. Now, where does thor come
Speaker 1: into this?
Speaker 2: Was thor? Technically Swedish, Danish or Finnish.
Speaker 1: Thor is part of Scandinavian folklore. So yeah, that would
Speaker 1: be Danish, Swedish, Norwegian.
Speaker 2: Well, I'm glad we cleared that up on our podcast
Speaker 2: Scandinavian Culture and three and Mythology.
Speaker 1: And those countries all speak very similar languages, like if
Speaker 1: you speak Danish, you can understand no Region. If you
Speaker 1: speak Swedish, you can understand Norwegian. If you speak Swedish
Speaker 1: you can understand Norwegion. Norwegians say they can't understand Danish,
Speaker 1: but we know they can. But a big difference between
Speaker 1: these countries is that Norway and Sweden have mountains. Denmark
Speaker 1: doesn't really have any.
Speaker 2: But anyways, back to physics on our question. Nicholas from
Speaker 2: Sweden has a question about how high a mountain can
Speaker 2: be on Earth before there are physical limitations to it,
Speaker 2: like Is there no limit to how big a mountain
Speaker 2: can be? Or is there a point of which the
Speaker 2: mountain just can grow?
Speaker 1: This is a really fun question. I love this question
Speaker 1: because there's lots of different ways you can answer it.
Speaker 1: You can answer it like a physicist, or you could
Speaker 1: try to answer it like a geologist, and it shows
Speaker 1: you how different sciences think about different things, and how
Speaker 1: all science is like about building models that kind of
Speaker 1: apply to the real world and have limitations.
Speaker 2: Wait, do you get different answers if you answer it
Speaker 2: as different scientists or do you come to the same conclusion.
Speaker 2: I would hope the same answer.
Speaker 1: You tell very different stories and you sometimes get roughly
Speaker 1: the same answer.
Speaker 2: Oh boy, this is going to depend on the definition
Speaker 2: of a mountain now, or like the definition of height
Speaker 2: or size.
Speaker 1: Like all of science, it's going to depend on what
Speaker 1: you include in your description and what you don't. So,
Speaker 1: for example, if we're going to take a physics point
Speaker 1: of view, the physicist in me says, let's just think
Speaker 1: about a mountain and like a big cone of rock,
Speaker 1: and let's ask what's the tallest pile of rocks with
Speaker 1: the biggest cone you can build where the top doesn't
Speaker 1: have so much pressure that it like crushes the bottom.
Speaker 1: Think of it like building a skyscraper.
Speaker 5: Hmmm.
Speaker 2: You're saying that if I just pile a bunch of
Speaker 2: rocks or dirt, at some point the weight of it
Speaker 2: is going to be so much that something's going to
Speaker 2: happen to the bottom of it.
Speaker 1: Exactly. Rock is not infinitely strong, right. You make a
Speaker 1: super tall tower of rock, and the pressure on the
Speaker 1: bottom rock is going to be so great that it's
Speaker 1: going to start to flow. It doesn't have to melt,
Speaker 1: it's not necessarily going to become liquid, but it will
Speaker 1: start to flow because the pressure is so great. This
Speaker 1: actually happens already inside the Earth and the sort of
Speaker 1: upper layers of the Earth. The rock is not melted,
Speaker 1: it's not liquid, but it does still flow because of
Speaker 1: incredible pressure. So all materials have something called compressive strength
Speaker 1: that if you push on it hard enough, it will
Speaker 1: flow or crumble.
Speaker 2: Right, But that assumes it has somewhere to flow, right, Yeah,
Speaker 2: that's right. Like, if it can flow, it can be
Speaker 2: pretty almost infinitely compressible.
Speaker 1: Yeah. In this case, though, if you're building a mountain,
Speaker 1: then what's going to happen is that your mountain's base
Speaker 1: is going to flow and it's not going to get taller.
Speaker 1: So as you add rocks to the top, you're going
Speaker 1: to be adding pressure on the bottom, and the bottom
Speaker 1: is going to flow and spread out. So there's a
Speaker 1: sort of physics model there that can help you calculate,
Speaker 1: like what is the tallest pile of rocks you can
Speaker 1: make without the base spreading out from underneath you?
Speaker 2: Right, I guess maybe it does maybe come down to
Speaker 2: the definition of a mountain, which is like a pile
Speaker 2: of rocks above some arbitrary level that you pick to
Speaker 2: be the base of the mountain.
Speaker 1: And so if you define a mountain like that, you
Speaker 1: have a flat plane, you start by piling rocks and
Speaker 1: you build those up and build those up. Then it's
Speaker 1: a pretty simple model. And the answer you get for
Speaker 1: like what is the tallest pile of rocks you can build,
Speaker 1: depends on just a couple of things. It depends on
Speaker 1: the gravity, because the more gravity there is, the more
Speaker 1: pressure there's going to be on the bottom. Right, in
Speaker 1: a no gravity environment, there's no pressure. In a higher
Speaker 1: gravity environment is more pressure. And it also depends on
Speaker 1: the compressive strength of the material, Like if you build
Speaker 1: it out of titanium or you build it out of popcorn,
Speaker 1: you're going to get a different height mountain. But just
Speaker 1: really those two numbers are all that it depends on.
Speaker 2: Well, I think there's something in civil engineering where there's
Speaker 2: sort of like a maximum angle that you can pile
Speaker 2: a bunch of rocks or a bunch of dust or
Speaker 2: a bunch of powder. And so I think what you're
Speaker 2: saying is that at some point, if you just start
Speaker 2: piling rocks, at some point the bottom rocks are going
Speaker 2: to float outwards to the sides, right, exactly, And that's
Speaker 2: kind of why like a pile of rocks it looks
Speaker 2: like triangle basically.
Speaker 1: Right, Yeah, that's exactly right.
Speaker 2: And the more stuff you put into it, the more
Speaker 2: the more it's just gonna basically fall off to the
Speaker 2: side and roll down the side of the mountain.
Speaker 1: And this is a very simplistic model, right, or ignoring
Speaker 1: everything happening under the surface of the thing that formed
Speaker 1: the mountain. Right, Nobody actually builds mountains this way, starting
Speaker 1: with a pile of rocks and adding them one at
Speaker 1: a time. But in this simplistic model, you can plug
Speaker 1: in the numbers and say how tall could you make
Speaker 1: a mountain out of granite? For example, if you had
Speaker 1: the gravitational force of the Earth, and the answer you
Speaker 1: get is about twenty two kilometers high, which you know
Speaker 1: for a physics model is pretty good, Like it's order
Speaker 1: of magnitude the right answer.
Speaker 2: Interesting. I mean, you plugged in the numbers and you
Speaker 2: got twenty two kilometers, But what does your model say
Speaker 2: happens after twenty two kilometers.
Speaker 1: After twenty two kilometers, then as you add rocks on top,
Speaker 1: the bottom breaks down and it spreads out, So it
Speaker 1: basically max is out at twenty two kilometers.
Speaker 2: Like, you add another rock and the base gets wider.
Speaker 1: Yeah, exactly, So you can get a higher volume to
Speaker 1: your mountain, but you can't get a taller mountain.
Speaker 2: Oh I see, So the more rocks you add, the
Speaker 2: just the wider with.
Speaker 1: Yet yeah, you get a fatter mountain. Exactly.
Speaker 2: But this again, this depends on a totally flat world, right.
Speaker 1: Yes, it depends on a totally flat world. And it
Speaker 1: also ignores the way we know that mountains are made. Right.
Speaker 1: In reality, mountains are not made by people piling rocks
Speaker 1: on top of a flat plane. They're made by tectonic plates.
Speaker 1: Slamming into each other with certain forests and certain speed,
Speaker 1: and then one of them subducting under the other, forcing
Speaker 1: it up to create those mountain ranges, like the tallest
Speaker 1: mountains on Earth, Everest come from the Indian plates slimming
Speaker 1: into the Asian plate and creating the Himalayas.
Speaker 2: M but pushing the rocks.
Speaker 1: Up, pushing some of the rock up exactly. And for
Speaker 1: a long time in geology there's been a debate about
Speaker 1: what limits the height of mountains, some people arguing that
Speaker 1: it's the pressure from the tectonic plates, and other people
Speaker 1: arguing that no, it's actually erosion, because you know, weather
Speaker 1: and water and rivers and wind and all that stuff
Speaker 1: breaks down mountain eventually. So for a long time people
Speaker 1: were arguing about which of the two factors controls the
Speaker 1: height of mountains.
Speaker 2: Well, there's also in geology buoyancy, right, And at some
Speaker 2: point when you pile an of rocks, it starts to
Speaker 2: sink into the earth.
Speaker 1: That's true. But here you have two plates pushing on
Speaker 1: top of each other. So one plate is being pushed
Speaker 1: up by the other plate, one is sinking down, and
Speaker 1: one is getting pushed up. Right, So I'm not sure
Speaker 1: that buoyancy is a factor. I just read a paper
Speaker 1: in Nature that came out last year that showed that
Speaker 1: the height of mountains around the Earth is totally correlated
Speaker 1: with the pressure between the plates. Like you can measure
Speaker 1: the forces along the two plates, and they show that
Speaker 1: the greater the pressure between the two plates, the taller
Speaker 1: the mountains, which suggests that actually erosion is basically irrelevant
Speaker 1: and the only thing that determines the heights of mountains
Speaker 1: on Earth is how hard these plates are slamming into
Speaker 1: each other or or me.
Speaker 2: That's the biggest factor though, right.
Speaker 1: Yeah, that's the overwhelming factor to within their arabars. And
Speaker 1: that means that if you've wanted a taller mountain, you need,
Speaker 1: like in to zoom faster along the surface of the
Speaker 1: Earth before it slammed into China, because it would apply
Speaker 1: a greater pressure and make taller Himalayas. Right.
Speaker 2: But once you form a mountain, I think another limiting
Speaker 2: factor is, like I said, the buoyancy of it, right,
Speaker 2: because the rocks inside the Earth are sort of soft
Speaker 2: in a geological scale, and so that at some point
Speaker 2: the mountain is going to sink into the Earth.
Speaker 1: Yeah, I think that in reality, there's lots of things
Speaker 1: that all contribute but me and we can never model
Speaker 1: all the processes that control these things, so we try
Speaker 1: to just isolate, like what is the dominant factor. Then
Speaker 1: this Nature paper claims that it's the force between these
Speaker 1: two mountains, and that's really cool because it makes you
Speaker 1: think about like what might have happened earlier on Earth,
Speaker 1: Like when the Earth was hotter than the convection cells
Speaker 1: within the Earth were probably cycling faster, which might have
Speaker 1: meant plate tectonics were pushing things together harder, which might
Speaker 1: mean that there were taller mountains on Earth earlier.
Speaker 2: On right, right, But I guess this is I think
Speaker 2: you're talking about the origin of mountains, and like here
Speaker 2: on Earth, this is how mountains were formed. Maybe they're
Speaker 2: correlated to the pressure between the tectonic plates, but I
Speaker 2: think Nicholas's question is like, what's the biggest one you
Speaker 2: can form?
Speaker 1: Yeah, good point, And there I guess physics says twenty
Speaker 1: two kilometers is the tallest mountain you could make on
Speaker 1: Earth without the base of it flowing out from under you.
Speaker 1: And as you say, they're also buoyancy effects, So I
Speaker 1: would guess somewhere around that number around twenty kilometers.
Speaker 2: And then he also had a bit of a question
Speaker 2: here about the curvature of the Earth. How does that
Speaker 2: affect your calculation, because your calculation assumes a totally flat earth.
Speaker 1: Yeah, but on these scales, even a mountain is pretty
Speaker 1: small compared to the curvature of the Earth. So your
Speaker 1: mountain would have to be like, really really huge before
Speaker 1: the curvature affected it. So I think that in every
Speaker 1: case we can basically ignore the curvature.
Speaker 2: Well, I guess maybe the question is what would happen,
Speaker 2: Like if I took the Moon or maybe a whole
Speaker 2: other planet, I pulvarized it in the rocks, and I
Speaker 2: just started pouring those rocks in one place on Earth.
Speaker 2: It would at first start to make a mountain. And
Speaker 2: then at about twenty you're seeing out of about twenty
Speaker 2: two cols, the more rocks I pour into, the more
Speaker 2: it's just going to flow to the sides.
Speaker 1: Mm hmm, yeah exactly.
Speaker 2: And then and then what's going to happen is the
Speaker 2: Earth gonna end up kind of oblong shape like a
Speaker 2: cone head.
Speaker 1: Yeah, I mean, eventually it would grow wide enough that
Speaker 1: it just becomes a feature of the Earth, right, because
Speaker 1: the Earth varies and radius by more than twenty kilometers.
Speaker 2: All right, well, I guess that's the general answer for
Speaker 2: Nicholas Daniels says that Quartant's model, the biggest mountain that
Speaker 2: you can get on Earth would be about twenty two
Speaker 2: kilometers above sea level.
Speaker 1: But that's a simple physics model. It ignores lots of stuff.
Speaker 1: So before you submit a pitch to the US government
Speaker 1: to build the world's tallest mountain, please get a more
Speaker 1: accurate model.
Speaker 2: All right, thanks Nicholas for that question. So let's get
Speaker 2: to our other questions here about the Higgs field and
Speaker 2: the flow of time. So we'll dig into those, but
Speaker 2: first let's take a quick break. All right, we're answering
Speaker 2: listener questions here today, and our next question comes from Martin.
Speaker 4: Back in the seventeenth and eighteenth century, it was believed
Speaker 4: that there was an ether that which permeated the universe. This,
Speaker 4: of course, has now been disproved. However, fast forward many
Speaker 4: years and scientists have shown that there is a Higgs
Speaker 4: Boson field. Although not exactly the same, they do seem
Speaker 4: to be quite similar. My question is, are there other
Speaker 4: theories in the past that were disproved but are actually
Speaker 4: similar to theories or proofs that we believe to be
Speaker 4: true today.
Speaker 2: All right, great question here, going a little bit back
Speaker 2: in history about our ideas if what the universe was
Speaker 2: made out of. We used to have this idea of
Speaker 2: the ether in our classmers.
Speaker 1: Right, Yeah, the ether was an idea which was popular
Speaker 1: for quite a while to try to explain the mystery
Speaker 1: of what is light wiggling through? We understood sound waves
Speaker 1: were wiggles in air, and there were other kinds of waves,
Speaker 1: and there were waves in the ocean, and the idea
Speaker 1: that light was a wave raised the question of like
Speaker 1: what is light wiggling through? And so for a long
Speaker 1: time people imagine that space wasn't actually empty, it was
Speaker 1: filled with something the ether that light was propagating.
Speaker 2: Through, sort of like you know, we have air around
Speaker 2: us here on the surface of Earth, and sound waves
Speaker 2: are really just you know, pressure waves through air.
Speaker 1: Yeah, that's exactly right, And the speed of those waves
Speaker 1: is relative to the air that's the medium. And so
Speaker 1: you can like catch up to a sound wave and
Speaker 1: move with it, for example, as it moves through the medium.
Speaker 2: And so there was this idea that maybe light worked
Speaker 2: the same way as sound like maybe light is a
Speaker 2: wave that is being spread by something that's all around us.
Speaker 1: Yeah, exactly. And this was like a universized idea that
Speaker 1: all of space was filled with this stuff we hadn't
Speaker 1: ever discovered before, and then later the idea was discarded,
Speaker 1: and ever since then, this idea of an ether is
Speaker 1: so mocked in popular science a lot. You know, anytime
Speaker 1: you suggest anything that fills the universe, people are like, wow,
Speaker 1: well that sounds like the ether revisited. Ha ha ha,
Speaker 1: we know how all that worked out.
Speaker 2: Oh boy, I didn't know if this is it since
Speaker 2: we're so snarky.
Speaker 1: Well, I think there's an element to Martin's question, which
Speaker 1: is like, is this idea of a Higgs field which
Speaker 1: fills the universe? Is that just the ether revisited? You know,
Speaker 1: like should we be concerned about inventing ideas of stuff
Speaker 1: filling the universe because that didn't work out well for.
Speaker 2: Us once, But then later you sort of build quantum theory,
Speaker 2: which sort of relies on an idea that's very similar
Speaker 2: to either, right, quantum field.
Speaker 1: Yeah, So to put a pin in the story of
Speaker 1: the ether, the reason we didn't believe the ether exists
Speaker 1: is because light doesn't move through space the way sound
Speaker 1: moves through waves. Right. Sound moves at a constant speed
Speaker 1: relative to its medium, but light moves at a constant
Speaker 1: speed relative to any observer. So the Michaelson morally experiment
Speaker 1: showed that like can't be moving through the ether because
Speaker 1: as we move through the ether, we measure light to
Speaker 1: always have the same speed. It turns out that light
Speaker 1: just propagates through space actually to propagation through these quantum fields.
Speaker 1: So as you say we have this sort of like
Speaker 1: new updated version of the ether, instead of imagining the
Speaker 1: universe is filled with stuff as a medium for light
Speaker 1: to propagate through, we say that light propagates through space
Speaker 1: itself as fluctuations in those quantum fields. But importantly, and
Speaker 1: this is the big difference, those fields don't have a
Speaker 1: frame of reference like air does, so you can't catch
Speaker 1: up to a photon. Photons are always moving at the
Speaker 1: speed of light relative to the observer.
Speaker 2: I wonder if you're sort of getting up to our
Speaker 2: limits of knowledge, because you're talking sort of about relating
Speaker 2: relativity right and relative istic speeds to quantum theory and
Speaker 2: quantum fields, which the physicists actually been able to relate
Speaker 2: the two.
Speaker 1: So physicists cannot relate to general relativity, which is about
Speaker 1: the curvature space and gravity, to quantum fields. But we
Speaker 1: have successfully married special relativity things moving really really fast
Speaker 1: and even at the speed of light to quantum fields.
Speaker 1: And so quantum field theory is fully special relativistic and
Speaker 1: incorporates speed of light transmission and particles moving at the
Speaker 1: speed of light, all that stuff. So we have a
Speaker 1: very robust theory that unifies quantum mechanics and special relativity.
Speaker 2: Meaning that these ideas that you can go faster than
Speaker 2: the speed of light, that's built into quantum physics.
Speaker 1: Yeah, that's built into quantum physics exactly. And quantum physics
Speaker 1: tells us this fascinating picture of the universe, which sounds
Speaker 1: kind of familiar, like hm, the universe actually isn't empty
Speaker 1: out there. Space is filled with all of these quantum fields.
Speaker 1: There's lots of them. There's the Higgs field, but is
Speaker 1: also the electromagnetic field and the electron field, and all
Speaker 1: the quark fields and maybe fields for dark matter, we
Speaker 1: don't know. But space is filled with all of these
Speaker 1: weird quantum fields that are sort of reminiscent of the
Speaker 1: ether in the sense that like, oh, space isn't empty,
Speaker 1: there's stuff out there happening.
Speaker 2: And so I think Martin's question here is like, you know,
Speaker 2: we used to it. Now you're sort of seems can
Speaker 2: make fun of people who believed in the ether, but
Speaker 2: at the same time, now you believe that there is
Speaker 2: something sort of like the ether that you call quantum fields.
Speaker 2: And so I think his question is like, are there
Speaker 2: other examples of that? Like are there things we thought
Speaker 2: was right but then disproved but then later it turned
Speaker 2: out to be Well, it's sort of like this.
Speaker 1: Yeah, it's a great question, and it reminds us to
Speaker 1: be humble, right that things that we like chuckle at today,
Speaker 1: in the future people might be like, actually that was
Speaker 1: a good idea, and you should have pursued that a
Speaker 1: little bit more.
Speaker 2: Yeah, Like maybe you'll try skiing one day and like it,
Speaker 2: and you'd be like, oh my god, I should have
Speaker 2: been doing this for years.
Speaker 1: Yeah, maybe I'll learn how to ski at the speed
Speaker 1: of light. That'd be awesome.
Speaker 2: Yeah, of course, need it would take no time to
Speaker 2: do it, so see, like you would suffer very little.
Speaker 1: Perfect another really great story about the dismissal and then
Speaker 1: resurgence of a big idea is also connected to relativity.
Speaker 1: But this is general relativity, and it's the idea of
Speaker 1: the cosmological constant. You know. Einstein, when he he was
Speaker 1: developing his theory of the universe, how space is curved
Speaker 1: and how gravity's actually just the motion of stuff through
Speaker 1: that curved space instead of a force. He put together
Speaker 1: his theory of space time and he looked at it
Speaker 1: and he realized, hold on a second, if this is true,
Speaker 1: the universe has a bunch of mass in it, Why
Speaker 1: isn't the universe just collapsing. Why isn't the space getting
Speaker 1: curved in a way that everything just rushes together and
Speaker 1: collapses the universe. And he looked out in the universe
Speaker 1: and he thought the universe was static. He thought all
Speaker 1: the stars just sat out there in space forever. So
Speaker 1: he added a fudge factor, a cosmological constant, to the
Speaker 1: equations of general relativity to balance out the effects of
Speaker 1: mass and hang everything sort of on balance in place.
Speaker 2: He just made that up, like he's like, oh, this
Speaker 2: is weird. I'll just add a number here. Yeah.
Speaker 1: It turns out if you add a number, you avoid
Speaker 1: this disastrous prediction of the equations, and only a few
Speaker 1: years later he realized that that was sort of silly
Speaker 1: and unnecessary.
Speaker 2: Wait, what do you mean? He realized that he didn't
Speaker 2: need that constant or did other people? I think you
Speaker 2: didn't need it.
Speaker 1: No, he realized that we didn't need that constant, and
Speaker 1: he actually called it like a huge blunder later in life.
Speaker 2: Wouldn't didn't need it? Like, what was this mistake?
Speaker 1: Well, he was trying to describe a static universe, the
Speaker 1: universe where nothing is happening. There's no expansion, there's certainly
Speaker 1: no acceleration. And this is kind of a crazy theory anyway,
Speaker 1: because it predicts a universe sort of like balanced on
Speaker 1: a knife edge, you know, a little bit more matter
Speaker 1: and things would collapse, a little bit more cosmological constant
Speaker 1: and things would expand. So it wasn't really anyway a
Speaker 1: great description of the universe as we saw it. And
Speaker 1: then a few years later Hubble discovered that it anyway
Speaker 1: wasn't the universe we were living in, the universe wasn't static.
Speaker 1: It was expanding, right, there was this positive expansion of
Speaker 1: the universe. So Einstein figures, oh, well, you don't need
Speaker 1: the cosmological constant to balance the mass. You just have
Speaker 1: this positive expansion already the universe somehow began with this expansion,
Speaker 1: and the mass isn't enough to overcome that. And so
Speaker 1: that was Einstein's picture of the universe to accommodate what
Speaker 1: Hubble and lots of other people, of course, discovered that
Speaker 1: the universe was already expanding.
Speaker 2: And so if you find out that the universe is expanding,
Speaker 2: then you don't need that fudge factor. You can just
Speaker 2: explain it without it.
Speaker 1: Yeah, if the universe is expanding, then without that fudge factor,
Speaker 1: you have two options. Either we'll never collapse because the
Speaker 1: expansion is so fast, or we just haven't collapsed yet
Speaker 1: because enough time hasn't passed for gravity pull everything back together.
Speaker 1: So that was sort of Einstein's new picture, and he
Speaker 1: got rid of the cosmological constancy.
Speaker 2: He was like dope, he.
Speaker 1: Was like, oh, I didn't need that. That was a mistake.
Speaker 1: But then decades later it resurfaced and now it's a
Speaker 1: crucial part of our understanding of the universe.
Speaker 2: What do you mean what changed?
Speaker 1: Well, in two thousand we discovered that the universe isn't
Speaker 1: just expanding, it's expanding, and accelerating. The expansion is happening
Speaker 1: faster and faster every year. Remember Einstein's description of what
Speaker 1: was happening is, all right, there's some expansion, but it's
Speaker 1: slowing down because of gravity, and either it's going to
Speaker 1: peter out and turn around to come back to a crunch,
Speaker 1: or it's just going to sort of drift out gradually forever.
Speaker 1: But then we discovered this expansion isn't slowing down, it's
Speaker 1: speeding up. And in order to make that happen, what
Speaker 1: do you need? You've got to put back in the
Speaker 1: cosmological constant to make that acceleration happen.
Speaker 2: What So, without the fudge factor, then you just get
Speaker 2: a universe that's evenly expanding.
Speaker 1: Without it, you get a universe whose acceleration is either
Speaker 1: zero or negative. You need the cosmological constant to have
Speaker 1: positive acceleration to the expansion. And that's not to say
Speaker 1: we understand why that's happening. It's just like, can we
Speaker 1: even use the equations to describe what we see? And
Speaker 1: to do that we need Einstein's fudge factor to return.
Speaker 2: And is that the official name of it, Einstein's fudge factor?
Speaker 1: Eff. No, the much fancier name of the cosmological constant.
Speaker 1: But the cosmological constant just a number we put into
Speaker 1: the equations to describe the universe. Can we have no
Speaker 1: explanation for it, no mechanism that can describe it or
Speaker 1: predict it. Our attempts actually to calculate what the cosmological
Speaker 1: concept might be from the quantum fields that fill space
Speaker 1: give an answer that are off by ten to the
Speaker 1: one hundred. So we're nowhere near understanding why this constant
Speaker 1: has its number.
Speaker 2: Interesting, So that's kind of another modern day version of
Speaker 2: the either Are there any other concepts like that? In physics?
Speaker 1: They're all over the place. Another famous one is string theory.
Speaker 1: String theory actually originated as an attempt to describe how
Speaker 1: quarks interact. Now we describe quark interactions using the strong force,
Speaker 1: and we have a really nice theory of it called
Speaker 1: quantum chromodynamics, which explains the fields involved and the gluons
Speaker 1: and all that complicated stuff we've talked about on the podcast.
Speaker 1: But originally, in like the fifties and sixties, people were
Speaker 1: trying to use string theory to describe the strong interaction,
Speaker 1: but it didn't really work very well. And in nineteen
Speaker 1: seventy three when we discover the jpe side particle, which
Speaker 1: is a bound state of two quarks. That was really
Speaker 1: triumph for this other idea, this quantum chromo dynamics theory
Speaker 1: of the strong interactions. So people abandoned string theory. They
Speaker 1: were like a string theory total failure. Couldn't explain the
Speaker 1: strong interactions. And then about fifteen year years later, people realized, oh, actually,
Speaker 1: there are things you can do to string theory to
Speaker 1: make it to be able to describe not just the
Speaker 1: strong interaction, but every kind of interaction, maybe even gravity.
Speaker 1: And then you had the string theory revolutions of the
Speaker 1: eighties and nineties, and now string theory is everywhere. It's
Speaker 1: like the best candidate for our theory of everything.
Speaker 2: So it failed to describe one little thing. But then
Speaker 2: people figured out it can describe lots of other things,
Speaker 2: but doesn't it still fail to describe the one thing
Speaker 2: that it had failed to describe before.
Speaker 1: One of the challenges of string theory is that there's
Speaker 1: lots and lots of string theories, and so they thought
Speaker 1: initially that there was a basic problem with string theory
Speaker 1: that it couldn't describe the strong interactions. But that's because
Speaker 1: they hadn't yet considered like the right string theory, and
Speaker 1: so other people found ways to put constraints on the
Speaker 1: strings and add bells and whistles to them that allowed
Speaker 1: them to describe accurately the strong force and all the
Speaker 1: other stuff. The problem is, of course, we don't know
Speaker 1: which string theory is the right one, and we can't
Speaker 1: test it. So it's not like string theory is proven,
Speaker 1: but it's definitely a deep area of research where it
Speaker 1: was once abandoned.
Speaker 2: Right. It's exciting, it's maybe because of its potential, but
Speaker 2: we don't really know if it's true, which was sort
Speaker 2: of Martin's question, like is there something we thought wasn't
Speaker 2: true but now we think it's true.
Speaker 1: Yeah, that's fair. We definitely don't know that string theory
Speaker 1: is true, but it's no longer on the dust benef theories.
Speaker 3: All right.
Speaker 2: Sounds like physics is constantly changing, right, And things that
Speaker 2: ideas that we thought were working we would start out
Speaker 2: to work, and things we thought work some things don't work.
Speaker 2: It's a process.
Speaker 1: It's definitely a process, and we're constantly mining the past.
Speaker 1: If you look at the history of physics, there are
Speaker 1: lots of scenarios where like nothing happens for forty years
Speaker 1: and then somebody reads an old paper and they're like,
Speaker 1: hold on a second, this is a great idea. How
Speaker 1: come nobody's doing this? And sometimes ideas just need their moment,
Speaker 1: the right person to read them at the right time
Speaker 1: and connect them with current thinking. So we're constantly digging
Speaker 1: into our own past to look for good ideas that
Speaker 1: we've ignored.
Speaker 2: Make physics sound kind of fashionable and fickle.
Speaker 1: Absolutely, remember, physics, like all science, is of the people,
Speaker 1: by the people, for the people. It's not like methodical
Speaker 1: or consistent in the way that it explores all ideas.
Speaker 1: It's just like, what are people into, what are they
Speaker 1: thinking about? What ideas do they have? What inspires them?
Speaker 1: It's a creative process.
Speaker 2: What's trendy?
Speaker 4: Now?
Speaker 2: Would you spell fickle with a pH then or fashionable
Speaker 2: with a pH?
Speaker 1: Sh Ion, you're in charge of the names, so I
Speaker 1: defer to you. Good, thank you, I'll take that title.
Speaker 2: All right. Well, let's get to our last question here
Speaker 2: of the day, which is about the flow of time
Speaker 2: and universal symmetry. So let's dig into that. But first
Speaker 2: let's take another quick break. Right, We're answering listener questions.
Speaker 2: And our second question was whether there are a lot
Speaker 2: of concepts in physics that we thought weren't true, but
Speaker 2: then we realize we're true or sort of true. And
Speaker 2: it sounds like there are, oh, absolutely, and it sounds
Speaker 2: like physics is always changing. And so that was the
Speaker 2: answer for that. But now we have our third question
Speaker 2: of the day, which is about time.
Speaker 5: Hell hold, I'm looking for a place in the universe.
Speaker 5: Will time go way faster related to the out and
Speaker 5: envelopment of this place? Is there a place like that?
Speaker 5: What can make this place real? I thought maybe some
Speaker 5: gravitational a different speeds effect can cause it. What did
Speaker 5: you say? Thank you here? Nadav from Israel?
Speaker 2: All right, interesting question. I'm not one hundred percent sure
Speaker 2: I understand it, but it sounds like they're asking, can
Speaker 2: you somehow make time go faster?
Speaker 1: And think he wants like a box he can step
Speaker 1: in where things will go much much faster than when
Speaker 1: he steps out. Less time will have passed on the
Speaker 1: outside than on the inside.
Speaker 2: More time. I think, like I think what he's may
Speaker 2: be referring to is that, you know, a lot of
Speaker 2: the ideas we have about time is that they're about
Speaker 2: slowing down time, right, Like if you go close to
Speaker 2: the speed of lighter really fast and time will slow
Speaker 2: down for you, or if you go near a black hole,
Speaker 2: time will slow down for you. I wonder if he's asking,
Speaker 2: you know, is there some sort of effect in physics
Speaker 2: that will do the opposite and make time go faster.
Speaker 1: Yeah, it'll go faster for the people like in the box, right,
Speaker 1: so that people step in the box, they're in the
Speaker 1: box for a year in our time, and they come
Speaker 1: out and one hundred years is past for them. That's
Speaker 1: what he wants, right.
Speaker 2: Right, right, so time moves more, time has gone by
Speaker 2: for them, they're older.
Speaker 1: Yeah, time has flowed faster inside the box and outside
Speaker 1: the box.
Speaker 4: Right.
Speaker 1: Yeah. It's a good question, and you're right that this
Speaker 1: is not something that's easy to assemble in physics, not
Speaker 1: something we naturally see, but we should dig into like
Speaker 1: why that works and how that works. But I do
Speaker 1: have an idea for an adove, though I think it's
Speaker 1: probably impractical.
Speaker 2: Hmmmm, Well, in practicality has never stopped physicists, So why
Speaker 2: start now?
Speaker 1: Exactly all right.
Speaker 2: So we're looking for a way to accelerate time, maybe
Speaker 2: like if you wanted to age your wine faster, you
Speaker 2: could stick it in this box and it would get
Speaker 2: older faster. Or if you want to grow your vegetables faster,
Speaker 2: I guess it's one they used for it.
Speaker 1: Yeah, absolutely, Or chemical reactions could happen faster. You could
Speaker 1: like make new fossil fuels in the blink of an
Speaker 1: eye rather than waiting one hundred million years.
Speaker 2: Yeah, there you go. If you want to like warn jeans,
Speaker 2: but you didn't want to wait and be fashiona willed
Speaker 2: with a pH you could use this machine.
Speaker 1: Yeah. Or you could roast to Thanksgiving turkey in a
Speaker 1: minute right instead of hours.
Speaker 2: Oh my gosh, that is the actual killer app for
Speaker 2: this fast slow organic food.
Speaker 1: There you go. Physics saves Thanksgiving.
Speaker 2: Yeah, there you go. All right, So what's your idea
Speaker 2: for making this happen? So first of all, why is
Speaker 2: it that we can only usually slow down time in
Speaker 2: the universe.
Speaker 1: Well, there's two different kinds of ways to change how
Speaker 1: time flows. One of them is based on speed velocity,
Speaker 1: and that one's symmetric. And then then one of them
Speaker 1: is based on gravity and a curvature of space, and
Speaker 1: that one is asymmetric. So the velocity one is the
Speaker 1: one people mostly think about. This is like, if you
Speaker 1: see a clock moving past you really fast, you're going
Speaker 1: to see it ticking slower than your clock. Right. So
Speaker 1: Jorges in a spaceship, he's flying by the earth, he
Speaker 1: is a clock. I'm watching his clock from the earth,
Speaker 1: comparing it to my clock, and I see Jorgey's clock
Speaker 1: is ticking slower. So Hoory's time is passing slower than mine.
Speaker 2: Right, It's going slow for everybody, which is weird.
Speaker 1: Yeah, because it's symmetric. You might think, well, if Daniel
Speaker 1: is seeing Jorges clock going slower, doesn't that mean Jorge
Speaker 1: is seeing Daniel's clock going faster. The answer is no,
Speaker 1: because Jorge also sees Daniel moving fast. Like if you're
Speaker 1: in the spaceship, from your perspective, that Earth is flying
Speaker 1: by you at high speed, and the same rule applies
Speaker 1: moving clocks run slow. You see my clock moving fast,
Speaker 1: so you see my clock ticking slower. So I see
Speaker 1: your time moving slow. You see my time moving slow.
Speaker 1: Nobody sees anybody's time moving quickly. And that's the whole
Speaker 1: puzzle of special relativity and the twin paradox which we've
Speaker 1: dug into other times on the episode, But that doesn't
Speaker 1: give you any way to speed up time.
Speaker 2: Well, maybe let's dig into it a little bit. So
Speaker 2: that's just how it looks to the two of us.
Speaker 2: For each of us as we pass by each other,
Speaker 2: but at some point, if we wanted to meet up again,
Speaker 2: one of us has to turn around, and for that person,
Speaker 2: time is going to move slower or faster.
Speaker 1: Right, So, if you decide to turn your spaceship around
Speaker 1: and come back to Earth so we can compare our
Speaker 1: clocks like right on top of each other, without any
Speaker 1: velocity relative to each other, then the rules of special
Speaker 1: relativity don't really apply anymore because when you turned around,
Speaker 1: you accelerated, and this simple description of special relativity only
Speaker 1: applies to things moving at constant velocity. When you turn around,
Speaker 1: that's acceleration. But you're right that something interesting happens when
Speaker 1: you turn around. When you turn around, you see time
Speaker 1: jump forward for me, so so far you've seen my
Speaker 1: time be slow. When you turn around as you turn around,
Speaker 1: that acceleration has this effect that you see my time
Speaker 1: jump forward, so that when you come back to Earth,
Speaker 1: our times are very similar to each other.
Speaker 2: Right, But like we're saying there's something called the twins paradogs,
Speaker 2: which is like, if you take two twins and you
Speaker 2: send one of them to the next star system, going
Speaker 2: at almost a suit of light, and then they come back,
Speaker 2: one of the twins will have aged faster than the other.
Speaker 1: That's right. So the one that takes that trip, that
Speaker 1: goes down in the spaceship, accelerates, turns around, comes back
Speaker 1: will be younger than the twin that stayed on Earth.
Speaker 2: So like yeah, so like if you want to slow
Speaker 2: down time for yourself, you would hop in a.
Speaker 1: Spaceship and go away, right, Yeah, that's right.
Speaker 2: So to make time move faster, wouldn't stick everybody else
Speaker 2: in the spaceship, send it off and then have it
Speaker 2: come back, and then I will have age more. I guess.
Speaker 2: Maybe the question is like why is it so one
Speaker 2: directional or is it one directional? Like what's the difference
Speaker 2: Twin A and Twin B.
Speaker 1: The difference is acceleration. While velocity is totally relative. Doesn't
Speaker 1: matter who's doing the moving, It just matters what you measure, right,
Speaker 1: there's no absolute frame of reference. Acceleration is not relative.
Speaker 1: So there is a difference between the twin that goes
Speaker 1: out in the spaceship and turns around, that's acceleration, and
Speaker 1: the one that just states on Earth and doesn't accelerate.
Speaker 1: So the effects of the flow of time are different
Speaker 1: on those two twins. That's why they're no longer symmetric.
Speaker 1: And in case where they're just passing each other in space,
Speaker 1: they both see the other one's time as going slowly,
Speaker 1: and that's perfectly symmetric because they just have relative velocity.
Speaker 1: Nobody's accelerating. One of them turns around, then they're accelerating.
Speaker 1: That makes one twin very different from the other twin
Speaker 1: from a physics point of view, and that's why they
Speaker 1: have different outcomes. And that actually is an idea there
Speaker 1: is like, well, if you accelerate, then you see time
Speaker 1: jump forward for everybody else, and so that's actually a
Speaker 1: way to accelerate the passage of time for the rest
Speaker 1: of the universe, right.
Speaker 2: Right, That's what I mean. It's like, accelerate, send everybody
Speaker 2: else on Earth and on a space ship and have
Speaker 2: it come back. That's a little bit logistically hard mmm.
Speaker 1: And it connects nicely with the other time dilation because,
Speaker 1: as we've talked about in the podcast before, acceleration is
Speaker 1: just like another way to see curvature in space. From
Speaker 1: a general relativistic point of view, acceleration and curvature are
Speaker 1: basically the same. You can even like create an event
Speaker 1: horizon with acceleration. Remember we talked once on the podcast
Speaker 1: about how you can like outpace a beam of light
Speaker 1: if you're constantly accelerating. And so this next with the
Speaker 1: other kind of time dilation we can talk about, and
Speaker 1: that's absolute time dilation due to curvature. If you see
Speaker 1: a clock near a black hole, for example, you will
Speaker 1: see its time going slower. But if somebody's at that
Speaker 1: clock and they're looking back at you and you're far
Speaker 1: away from the black hole, they don't see your time
Speaker 1: going slower. They see your time going faster, in the
Speaker 1: same way that like the twin that's accelerating sees time
Speaker 1: moving faster for everybody. A twin near a black hole
Speaker 1: will see time moving faster for everybody else outside in
Speaker 1: the universe. So this is asymmetric time dilation because curvature
Speaker 1: is not relative. Curvature is absolute, just like acceleration is.
Speaker 1: It's really the same thing.
Speaker 2: So like, for example, if you wanted to make time
Speaker 2: go faster for yourself. You might go off into orbit, right,
Speaker 2: because the Earth is also creating some curvature, and time
Speaker 2: is moving slower for things closer to the center of
Speaker 2: the Earth.
Speaker 1: Right, that's right. If you're further away from the Earth,
Speaker 1: then your time will be moving faster.
Speaker 2: So like a way to age your genes faster or
Speaker 2: your water line is to send it into space or
Speaker 2: to send it far away from the Earth.
Speaker 1: Yeah, that's right. So if you're hosting Thanksgiving, you should
Speaker 1: host it near a black hole, so you can send
Speaker 1: the turkey away from the black hole so that its
Speaker 1: time can move faster while it's cooking.
Speaker 2: Right, Right, But I guess what I'm saying is you
Speaker 2: don't need it the black hole. You could just do
Speaker 2: it here on Earth.
Speaker 1: Yeah, that's right, And it's a pretty small effect because
Speaker 1: the Earth doesn't have really dramatic curvature. Right. But the
Speaker 1: big picture we're sort of stumbling towards here is that
Speaker 1: for time to go faster, you need a place with
Speaker 1: less curvature. And so if you want everywhere in the
Speaker 1: universe to pass time slower than like your box, you
Speaker 1: basically need everywhere in the universe to be near a
Speaker 1: black hole or be near high curvature except for your box.
Speaker 1: So like my very impractical idea is similar to your
Speaker 1: impractical idea. Yours was make everybody in the universe accelerate
Speaker 1: except for the turkey or whatever mine is. Fill the
Speaker 1: universe with black holes except for where the turkey is,
Speaker 1: and then time will pass faster for the turkey than
Speaker 1: everybody else.
Speaker 2: Right, right, or shoot it with a turkey gun into
Speaker 2: the sky, although you won't get that much of an advantage.
Speaker 2: But I think maybe to answer the question of our listener,
Speaker 2: the answer is sort of like yes, sort of like
Speaker 2: if you want time to go faster than how it
Speaker 2: does here on the surface of Earth, then you can
Speaker 2: do it by putting it in a box and sending
Speaker 2: it off into space for a while. Right, time will
Speaker 2: move inside that box faster for a little bit.
Speaker 1: Yeah, the same way that time near a black hole
Speaker 1: moves more slowly. Time near the surface of the Earth
Speaker 1: moves more slowly than it does out in deep space.
Speaker 1: So basically our time is already slowed down a little bit,
Speaker 1: and you could take advantage of that by launching something
Speaker 1: into deep space where that effect isn't happening, and its
Speaker 1: time will go faster.
Speaker 2: Right, right, So if you want it to just age
Speaker 2: faster than everybody on the surface of Earth, that's doable.
Speaker 2: But I think maybe the question he had was, can
Speaker 2: you accelerate time where there's no curvature, or where there's
Speaker 2: no black holes or a planet like at the baseline
Speaker 2: speed of time in the universe? Maybe out there, whether
Speaker 2: you're nowhere near anything massive, can you make time go
Speaker 2: faster than that?
Speaker 1: We certainly don't know the answer to that question. Current
Speaker 1: physics would say it's impossible, But we also know the
Speaker 1: current physics doesn't really understand what time is or what
Speaker 1: space is, whether they're fundamental or whether they bubble up
Speaker 1: from something deeper or like a theory of quantum gravity,
Speaker 1: like maybe string theory. So we don't really understand what
Speaker 1: time is. So if I said absolutely not, then in
Speaker 1: fifty years somebody would be like, Haha, that guy didn't
Speaker 1: know what he was talking about.
Speaker 2: Right, And we know how snarchy physicists can be. They
Speaker 2: would totally laugh at you.
Speaker 1: Oh man, they're the worst. They go on these ski
Speaker 1: trips and they laugh at each other over hot coco.
Speaker 2: It's terror, right, They're like that Daniel doesn't know what
Speaker 2: he's missing.
Speaker 1: So current physics doesn't have a solution for you, Nadav,
Speaker 1: unless you want to fill the universe with black holes,
Speaker 1: or launch things into space.
Speaker 2: Right, or accelerate everybody else. Although it made me think,
Speaker 2: like with the twins paradogs, right, mm hmm, I send
Speaker 2: the twin out into space, they come back. They have
Speaker 2: a slower but to the twin that h slower, the
Speaker 2: other twin h faster. So what's the difference between the two.
Speaker 1: The difference is that one of them accelerated and the
Speaker 1: other one didn't.
Speaker 2: But they both accelerated relative to each other. The same.
Speaker 1: Acceleration is not relative. Acceleration is absolute. They can both
Speaker 1: hold accelerometers and they can both tell which one is
Speaker 1: doing the acceleration. They are not the same. Acceleration is
Speaker 1: absolute in the universe and velocity is relative.
Speaker 2: I see, like by visual site, they will both think
Speaker 2: they were both accelerating, but only one of them will
Speaker 2: really be accelerating.
Speaker 1: Yeah, if you're just measuring the relative distance between them,
Speaker 1: then you can't tell. But if you have an accelerometer,
Speaker 1: you can tell which one has had a force applied
Speaker 1: to them. Mmm. I see, it's a weird universe.
Speaker 2: All right, Well, I guess in the meantime, the best
Speaker 2: advice we can give is to just buy an air
Speaker 2: fryer or deep fryer for your turkey. That will definitely
Speaker 2: cook it faster.
Speaker 1: Oh I see, I thought by air fiument, a fryer
Speaker 1: which launches it up into the air like hind of
Speaker 1: the atmosphere where the less.
Speaker 2: Oh there you go. Yeah, and then bake it with
Speaker 2: baked with cosmic rays, so it'll be not just crispy,
Speaker 2: but also maybe mildly radioactive.
Speaker 1: Yeah, look for that in the daniel Le Jorge merch store,
Speaker 1: the skyfriar.
Speaker 2: That's right, perfect for relatives you don't like that.
Speaker 1: Much, relatives you want to fry with relativity.
Speaker 2: All right, Well, I think that answers that question, which
Speaker 2: is that physicists are not quite sure if you can
Speaker 2: accelerate time. So far, we can only think of ways
Speaker 2: to slow down time.
Speaker 1: Yeah, very impractical ways to speed it up, involving black
Speaker 1: holes and spaceships.
Speaker 2: Right, but even there, you'd have to like fill the
Speaker 2: universe with black holes except where you are.
Speaker 1: Yeah, that's an engineering problem.
Speaker 2: Right, Well, that's a big problem for everybody. If you
Speaker 2: did that, we would all suffer everyone at the Thanksgiving table.
Speaker 2: All right, well, thanks again to all of our listeners
Speaker 2: for sending in their questions. It's always fun to answer
Speaker 2: them here on the podcast and to see how curiosity
Speaker 2: works for every and what kinds of things people are
Speaker 2: thinking about and wondering about.
Speaker 1: So engage your curiosity, ask questions about the universe, and
Speaker 1: if you get a good one and write it to
Speaker 1: us questions at Daniel and Jorge dot com.
Speaker 2: That's right, call that lever that says ask the question.
Speaker 2: All right. We hope you enjoyed that. Thanks for joining us.
Speaker 2: See you next time.
Speaker 1: For more science and curiosity. Come find us on social
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Speaker 1: and now TikTok. Thanks for listening and remember that Daniel
Speaker 1: and Jorge Explain the Universe is a production of iHeartRadio.
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