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There are children, friends, and families walking riding on paths and roads every day. Remember they're real people with loved ones who need them to get home safely. Protect our cyclists and pedestrians because they're people too.

There are children, friends, and families walking riding on paths and roads every day. Remember they're real people with loved ones who need them to get home safely. Protect our cyclists and pedestrians because they're people too.

Go safely.

Go safely.

California from the California Office of Traffic Safety in Caltrans.

California from the California Office of Traffic Safety in Caltrans.

When you pull up to game night, ay, all new Camri, but it's actually Bingo Night Minigolf anyone, It's a Camri.

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I just think it's fascinating that it's such a fundamental force in the universe, right, Like it's basically the thing that builds galaxies and keeps planets moving right and gives structure to the entire cosmos.

I just think it's fascinating that it's such a fundamental force in the universe, right, Like it's basically the thing that builds galaxies and keeps planets moving right and gives structure to the entire cosmos.

That's right. On the largest scale, it's actually the most important force. It's the reason why things look the way they do. It's the reason why our planet is round. It's the reason why we're on the planet.

That's right. On the largest scale, it's actually the most important force. It's the reason why things look the way they do. It's the reason why our planet is round. It's the reason why we're on the planet.

It's pretty important, and yet we don't know a lot about it, right, Like, there's some really deep and strange mysteries about it.

It's pretty important, and yet we don't know a lot about it, right, Like, there's some really deep and strange mysteries about it.

On one hand, we have a theory which works really really well. On the other hand, we have questions about it which seems really really basic.

On one hand, we have a theory which works really really well. On the other hand, we have questions about it which seems really really basic.

And not only that, it's very different than all the other forces of nature.

And not only that, it's very different than all the other forces of nature.

That's right, one of these things is not like the other ones.

That's right, one of these things is not like the other ones.

Hi am morhee.

Hi am morhee.

I'm a cartoonist and I'm Daniel. I'm a particle physicist.

I'm a cartoonist and I'm Daniel. I'm a particle physicist.

And this is our podcast Daniel and Jorge explain the universe.

And this is our podcast Daniel and Jorge explain the universe.

In which a cartoonist and a physicists try to figure out how to make the universe understandable to anybody.

In which a cartoonist and a physicists try to figure out how to make the universe understandable to anybody.

Yeah, and today on the podcast we are examining a very heavy topic, gravity and specifically why is gravity so.

Yeah, and today on the podcast we are examining a very heavy topic, gravity and specifically why is gravity so.

Weak and strange. Gravity, as we said earlier, is something which controls the structure of the universe. I mean, the reason the Solar System looks the way it does is because of gravity. The reason the Earth is round is because of gravity. The reason we have galaxies is because of gravity.

Weak and strange. Gravity, as we said earlier, is something which controls the structure of the universe. I mean, the reason the Solar System looks the way it does is because of gravity. The reason the Earth is round is because of gravity. The reason we have galaxies is because of gravity.

The reason we weigh so much is because of gravity. Right, it's not my.

The reason we weigh so much is because of gravity. Right, it's not my.

Belt, No, that's because of late night cake eating.

Belt, No, that's because of late night cake eating.

But it's such a fundamental force of nature, right, Like it's present in our everyday life. We spend a lot of time thinking about gravity, right, how not to fall down, how not to drop things, how to go up buildings, how to go down buildings.

But it's such a fundamental force of nature, right, Like it's present in our everyday life. We spend a lot of time thinking about gravity, right, how not to fall down, how not to drop things, how to go up buildings, how to go down buildings.

Right, that's right. It seems like one of the most important forces. I mean, if you ask people, you know, to name a force or what kind of forces the experience in their life, gravity is the one that's present in their lives.

Right, that's right. It seems like one of the most important forces. I mean, if you ask people, you know, to name a force or what kind of forces the experience in their life, gravity is the one that's present in their lives.

Right.

Right.

You're climbing upstairs, you're fighting gravity, you trip, you fall down, you're feeling gravity. You look around you. The shape of things is controlled by gravity. And that's why it's particularly strange that gravity is the weakest force of all the forces we've discovered. It's by far the weakest.

You're climbing upstairs, you're fighting gravity, you trip, you fall down, you're feeling gravity. You look around you. The shape of things is controlled by gravity. And that's why it's particularly strange that gravity is the weakest force of all the forces we've discovered. It's by far the weakest.

Yeah, it's really strange to hear you say that, Like, how can gravity be weak? Like, you know, like it's keeping the whole Earth together, it's making the entire planet swing around, go in a circle, basically. Right. Without gravity, we would just shoot off into space.

Yeah, it's really strange to hear you say that, Like, how can gravity be weak? Like, you know, like it's keeping the whole Earth together, it's making the entire planet swing around, go in a circle, basically. Right. Without gravity, we would just shoot off into space.

That's right. It's a really strange situation. And there's other things about gravity we don't understand as well. It's really strange. It doesn't play well with the other forces. It's very, very weak. It's a total mystery to science, except that we have a theory which works beautifully right. We can calculate exactly how mercury orbits the sun. We can send things in outer space and know with to millimeter precision exactly where they're going to land. We have a working theory that we can use, right, but we don't understand it on a conceptual level. We have these basic, deep questions about what gravity is and how the universe works because of it.

That's right. It's a really strange situation. And there's other things about gravity we don't understand as well. It's really strange. It doesn't play well with the other forces. It's very, very weak. It's a total mystery to science, except that we have a theory which works beautifully right. We can calculate exactly how mercury orbits the sun. We can send things in outer space and know with to millimeter precision exactly where they're going to land. We have a working theory that we can use, right, but we don't understand it on a conceptual level. We have these basic, deep questions about what gravity is and how the universe works because of it.

So it's a weird question, and maybe one of the people hadn't thought about before. So Daniel went out as usual and asked people on the street, why do you think gravity is so weak?

So it's a weird question, and maybe one of the people hadn't thought about before. So Daniel went out as usual and asked people on the street, why do you think gravity is so weak?

Here's what a random selection of folks who were willing to talk to me on a Tuesday morning had to say about gravity.

Here's what a random selection of folks who were willing to talk to me on a Tuesday morning had to say about gravity.

I don't know.

I don't know.

I should don't know about that, all right. I thought it was a pretty strong force. I don't know, but yeah, because.

I should don't know about that, all right. I thought it was a pretty strong force. I don't know, but yeah, because.

It depends on the distance and it's long range one. So that's why we feel it very weak most of the time. Cool, No, Okay, I have no I'm sorry, it's not very fruitful.

It depends on the distance and it's long range one. So that's why we feel it very weak most of the time. Cool, No, Okay, I have no I'm sorry, it's not very fruitful.

Hmmm, I have no idea, but I'd be interested in finding out why.

Hmmm, I have no idea, but I'd be interested in finding out why.

All right, that was that was pretty good. Most people weren't surprised when you said gravity's weak.

All right, that was that was pretty good. Most people weren't surprised when you said gravity's weak.

I don't know. I feel like if all the questions I've asked people, this is the one that flumms them the most. You know, people were like, what, I have no idea, or they had crazy ideas why gravity must be weak. I feel like usually we get one person who knows what the answer is or has a good clue about what's going on. This time, I feel like almost everybody was pretty clueless. I mean, one person said I always thought gravity was pretty strong, right, which kind of sums up the situation, right. Gravity's omnipresent in our lives. It dominates our experience, and yet it's so weak compared to the other really powerful forces we've discovered.

I don't know. I feel like if all the questions I've asked people, this is the one that flumms them the most. You know, people were like, what, I have no idea, or they had crazy ideas why gravity must be weak. I feel like usually we get one person who knows what the answer is or has a good clue about what's going on. This time, I feel like almost everybody was pretty clueless. I mean, one person said I always thought gravity was pretty strong, right, which kind of sums up the situation, right. Gravity's omnipresent in our lives. It dominates our experience, and yet it's so weak compared to the other really powerful forces we've discovered.

Well, some people a couple of answers were that it had to do with distance, like gravity gets really weak with distance.

Well, some people a couple of answers were that it had to do with distance, like gravity gets really weak with distance.

That's right, And the problem there is that all the forces get weak with distance, like electromagnetism also falls as a distance grows. Right, So all of these forces follow this one over r squared rule or are as your distance from the thing that's giving.

That's right, And the problem there is that all the forces get weak with distance, like electromagnetism also falls as a distance grows. Right, So all of these forces follow this one over r squared rule or are as your distance from the thing that's giving.

You the force, right, maybe maybe right?

You the force, right, maybe maybe right?

Maybe yeah, mostly we think, And so that can't be the answer, right, because all the other forces have that same feature.

Maybe yeah, mostly we think, And so that can't be the answer, right, because all the other forces have that same feature.

So when you say it's the weak is it's not that it changes over distances differently than the other forces.

So when you say it's the weak is it's not that it changes over distances differently than the other forces.

That's right. So maybe we should talk about what the forces are and compare them to each other so folks can get an understanding of how crazy weak gravity is.

That's right. So maybe we should talk about what the forces are and compare them to each other so folks can get an understanding of how crazy weak gravity is.

Right. So, Daniel, what are the forces of nature besides a bad movie with Ben Affleck than Center Bullet.

Right. So, Daniel, what are the forces of nature besides a bad movie with Ben Affleck than Center Bullet.

Well, I think comedy. Comedy is definitely a force of nature. You know, it solves big problems around the world. Now, the fundamental forces are electromagnetism, right, that's the one that controls electricity and magnetism obviously, and his responsible for the cool things like light and lightning and all that cool stuff. And then there's the weak nuclear force, which is a force which is responsible for radioactive decay of a nuclei, right, And the cool thing about electricity and magnetism and the weak nuclear force. Is that we actually have shown that there are two sides of the same coin. As a particle physicist, we refer to them as one force. We call it the electro week. So sort of magnetism lost out there in the name merger, right, it should be electromagnetic week. But nobody voted to keep magnetism in the sort of the name of the partners in a law firm.

Well, I think comedy. Comedy is definitely a force of nature. You know, it solves big problems around the world. Now, the fundamental forces are electromagnetism, right, that's the one that controls electricity and magnetism obviously, and his responsible for the cool things like light and lightning and all that cool stuff. And then there's the weak nuclear force, which is a force which is responsible for radioactive decay of a nuclei, right, And the cool thing about electricity and magnetism and the weak nuclear force. Is that we actually have shown that there are two sides of the same coin. As a particle physicist, we refer to them as one force. We call it the electro week. So sort of magnetism lost out there in the name merger, right, it should be electromagnetic week. But nobody voted to keep magnetism in the sort of the name of the partners in a law firm.

Nobody lobbied for weak electro.

Nobody lobbied for weak electro.

Or magneto weak force. Yeah, yeah, again, we are suffering the fate of some anonymous committee of scientists that get to name these things. Right, Who are these people?

Or magneto weak force. Yeah, yeah, again, we are suffering the fate of some anonymous committee of scientists that get to name these things. Right, Who are these people?

Probably some grad student, right or some you know, like this is really weird, we'll call it this.

Probably some grad student, right or some you know, like this is really weird, we'll call it this.

Yeah. So we have electricity and magnetism, which is a single force. We have the weak nuclear force, which is really should be combined with electricity magnetism. And then there's the strong nuclear force. And this is the one that holds the nucleus together. You know, the nucleus is of just a bunch of positively charged protons and neutral neutrons. Right, it says only positively charged particles in the nucleus. So you might think, what it even holds the nucleus together. Right, you have all this positively charged stuff should be repelling themselves. Well, it's the strong nuclear force, and it does so by exchanging these crazy little particles we call gluons, and that holds the nucleus together, and it's pretty strong. It's even stronger than electromagnetism.

Yeah. So we have electricity and magnetism, which is a single force. We have the weak nuclear force, which is really should be combined with electricity magnetism. And then there's the strong nuclear force. And this is the one that holds the nucleus together. You know, the nucleus is of just a bunch of positively charged protons and neutral neutrons. Right, it says only positively charged particles in the nucleus. So you might think, what it even holds the nucleus together. Right, you have all this positively charged stuff should be repelling themselves. Well, it's the strong nuclear force, and it does so by exchanging these crazy little particles we call gluons, and that holds the nucleus together, and it's pretty strong. It's even stronger than electromagnetism.

Well, let's take a step back. So in the universe there's stuff.

Well, let's take a step back. So in the universe there's stuff.

There's like, yes, firm that there is stuff in the universe. Yes, without reservation, there is stuff.

There's like, yes, firm that there is stuff in the universe. Yes, without reservation, there is stuff.

I'm glad we saw that question. But I mean it's like there's stuff that has substance to it, that has mass to it, or you know that it sort of exists. And then there's also besides that, how these things interact with each other, like how they affect each other.

I'm glad we saw that question. But I mean it's like there's stuff that has substance to it, that has mass to it, or you know that it sort of exists. And then there's also besides that, how these things interact with each other, like how they affect each other.

That's right. There's the matter and then there's the forces. Right, the forces affect how they interact with each other.

That's right. There's the matter and then there's the forces. Right, the forces affect how they interact with each other.

And that's pretty much the universe. That's like, it's matter and forces.

And that's pretty much the universe. That's like, it's matter and forces.

Yeah, one way to look at the universe is that it's particles, right, or you would say matter and their forces. In modern particle physics, we think about one level deeper, which is we think of quantum fields and quantum fields are responsible both for matter and for forces. So we can talk about that maybe in another podcast. What is a quantum field? And how can I get one? You know, for lease or rent? What can they do for me? But yeah, I think it's fair still to think about the universe in terms of particles and forces.

Yeah, one way to look at the universe is that it's particles, right, or you would say matter and their forces. In modern particle physics, we think about one level deeper, which is we think of quantum fields and quantum fields are responsible both for matter and for forces. So we can talk about that maybe in another podcast. What is a quantum field? And how can I get one? You know, for lease or rent? What can they do for me? But yeah, I think it's fair still to think about the universe in terms of particles and forces.

On that note, let's take a quick break.

On that note, let's take a quick break.

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There are only four kinds of forces.

There are only four kinds of forces.

Yeah, there are four kinds of forces. So electromagnetism, weak nuclear force, strong nuclear force, and then of course gravity. Right, that's the fourth force that we've discovered.

Yeah, there are four kinds of forces. So electromagnetism, weak nuclear force, strong nuclear force, and then of course gravity. Right, that's the fourth force that we've discovered.

Okay.

Okay.

The fascinating thing is that different particles feel different forces, right, Like, some particles feel this set of forces. Some particles feel those set of force for example, right, particles with electric charge feel electromagnetism. Right. The electron, for example, is negatively charged, the proton is positively charged. You bring them close together, they're gonna pull on each other. They're gonna stuck each other together, right, because they have opposite charges. We all know that, but you bring a neutral particle nearby, it just totally ignores it, right, It doesn't feel it at all. Right, Right, It's like it's like somebody's walking through a crowd of people shouting, but they have headphones on so they can't hear anything. They're totally oblivious to it.

The fascinating thing is that different particles feel different forces, right, Like, some particles feel this set of forces. Some particles feel those set of force for example, right, particles with electric charge feel electromagnetism. Right. The electron, for example, is negatively charged, the proton is positively charged. You bring them close together, they're gonna pull on each other. They're gonna stuck each other together, right, because they have opposite charges. We all know that, but you bring a neutral particle nearby, it just totally ignores it, right, It doesn't feel it at all. Right, Right, It's like it's like somebody's walking through a crowd of people shouting, but they have headphones on so they can't hear anything. They're totally oblivious to it.

It's kind of like how we talked about in a previous podcast. They're almost like languages or like social media platforms. Like some people are on Twitter, some people are on Facebook, but some people are not on this. And so if somebody, if you're not on Twitter and somebody sends you a tweet, you're not going to get it. And so it's just different ways that particles interact.

It's kind of like how we talked about in a previous podcast. They're almost like languages or like social media platforms. Like some people are on Twitter, some people are on Facebook, but some people are not on this. And so if somebody, if you're not on Twitter and somebody sends you a tweet, you're not going to get it. And so it's just different ways that particles interact.

That's right. Gravity is the Google plus social media, right because nobody uses the trends. It's ancient but powerless. Yeah, And so different particles feel different forces. And for example, an electron, while it feels electromagnetism because it has a negative charge, it doesn't feel the strong force at all. It will pass right by a bunch of particles that are really tugging on each other with a strong force and not be affected at all. Whereas quarks. Quarks feel all the forces. They feel a strong force, which is how they get pulled together in the nucleus. Remember, protons and neutrons are made of quarks. Quarks feel electromagnetism because they have electric charge, they feel the weak force. They also feel gravity, of course, because they have masks. So quarks get their fingers in everything.

That's right. Gravity is the Google plus social media, right because nobody uses the trends. It's ancient but powerless. Yeah, And so different particles feel different forces. And for example, an electron, while it feels electromagnetism because it has a negative charge, it doesn't feel the strong force at all. It will pass right by a bunch of particles that are really tugging on each other with a strong force and not be affected at all. Whereas quarks. Quarks feel all the forces. They feel a strong force, which is how they get pulled together in the nucleus. Remember, protons and neutrons are made of quarks. Quarks feel electromagnetism because they have electric charge, they feel the weak force. They also feel gravity, of course, because they have masks. So quarks get their fingers in everything.

They get the feels for everything, They feel everything erect.

They get the feels for everything, They feel everything erect.

They got the strong feels. Of course, they're really deeply emotional part of that. And on the other side of the spectrum, you've got things like neutrinos and trinos don't have electric charge, so they ignore all electricity and magnetism. Right, they don't interact with light. They're invisible. They pass right through anything that They ignore electromagnetic bonds, so they pass through most materials. They don't feel the strong force. The only way they interact is with the weak force. And the weak force is pretty weak, which is why neutrinos can mostly just pass through matter unaffected.

They got the strong feels. Of course, they're really deeply emotional part of that. And on the other side of the spectrum, you've got things like neutrinos and trinos don't have electric charge, so they ignore all electricity and magnetism. Right, they don't interact with light. They're invisible. They pass right through anything that They ignore electromagnetic bonds, so they pass through most materials. They don't feel the strong force. The only way they interact is with the weak force. And the weak force is pretty weak, which is why neutrinos can mostly just pass through matter unaffected.

So we have four fundamental forces, right, and gravity is one of these forces. And so when you say that gravity is weak, you actually mean it's weak compared to these other three forces.

So we have four fundamental forces, right, and gravity is one of these forces. And so when you say that gravity is weak, you actually mean it's weak compared to these other three forces.

That's right. And so the ranking is the strong force is the strongest, right, so that one is actually well named. Congratulations, you know anonymous group of scientists. Yeah, we should be called the as of twenty eighteen, currently known to be the strongest force force. Right after that comes electromagnetism, and you know, we know that force's pretty powerful. You stick your finger in the socket, you're gonna feel the wrath of electromagnetism. Right, It's not an unfamiliar feeling.

That's right. And so the ranking is the strong force is the strongest, right, so that one is actually well named. Congratulations, you know anonymous group of scientists. Yeah, we should be called the as of twenty eighteen, currently known to be the strongest force force. Right after that comes electromagnetism, and you know, we know that force's pretty powerful. You stick your finger in the socket, you're gonna feel the wrath of electromagnetism. Right, It's not an unfamiliar feeling.

Right, try to stick your finger in anything, you feel it, right, because it's electromagnetism is the force that keeps you from basically passing through the table or passing through your car.

Right, try to stick your finger in anything, you feel it, right, because it's electromagnetism is the force that keeps you from basically passing through the table or passing through your car.

Right, that's right, because electromagnetism is the basis of chemical bonds, right, and chemical bonds are really the thing that form the structure of your body. Right. You think of your body is like a bunch of particles, but it's held together by all these forces. It's like a chain link fence binding together these little particles that prevents you from passing through something else. Yeah, So we got the strong force, and then electromagnetism and then actually the weak nuclear force. Right, this is the force that like powers neutrinos and radioactive decay. It's much weaker than electromagnetism and much weaker than the strong force.

Right, that's right, because electromagnetism is the basis of chemical bonds, right, and chemical bonds are really the thing that form the structure of your body. Right. You think of your body is like a bunch of particles, but it's held together by all these forces. It's like a chain link fence binding together these little particles that prevents you from passing through something else. Yeah, So we got the strong force, and then electromagnetism and then actually the weak nuclear force. Right, this is the force that like powers neutrinos and radioactive decay. It's much weaker than electromagnetism and much weaker than the strong force.

Even weaker than the weak is gravity.

Even weaker than the weak is gravity.

That's right. If you make a list like strong force, electromagnetism, in the weak force, then you should leave like one hundred blank pages, and then you get to gravity. Because when we compare these forces, we put things like an equal distance apart, and we compare the strength of the forces. Gravity is ten to the thirty six times weaker than the weak force. That's ten with thirty six zeros in front of it.

That's right. If you make a list like strong force, electromagnetism, in the weak force, then you should leave like one hundred blank pages, and then you get to gravity. Because when we compare these forces, we put things like an equal distance apart, and we compare the strength of the forces. Gravity is ten to the thirty six times weaker than the weak force. That's ten with thirty six zeros in front of it.

But isn't that sort of a matter of units or scale? Do you know what I mean? Like, it's much weaker, but only if you compare apples to apples, right, or just oranges.

But isn't that sort of a matter of units or scale? Do you know what I mean? Like, it's much weaker, but only if you compare apples to apples, right, or just oranges.

That's right, But put two protons next to each other, right, h Two protons have a certain amount of mass and a certain amount of electric charge, and the force of their charges is going to be much much stronger than the force from their masses.

That's right, But put two protons next to each other, right, h Two protons have a certain amount of mass and a certain amount of electric charge, and the force of their charges is going to be much much stronger than the force from their masses.

Oh I see.

Oh I see.

So yeah, if everything was much much more massive, then there would be stronger gravity. But you can compare these things apples to apples by comparing them at you know the same distance and the same basic unit of interaction.

So yeah, if everything was much much more massive, then there would be stronger gravity. But you can compare these things apples to apples by comparing them at you know the same distance and the same basic unit of interaction.

Right, But what if you take an apple put it next to another apple?

Right, But what if you take an apple put it next to another apple?

Well, I think you can do that experiment. Nothing's going to happen because gravity is so weak. Right. You don't see two apples like pulling themselves together on the counter, right, And though built in apple collider, you know the apples are not drawn to each other. Gravity is a super weak force, and you can see this yourself. Right, you can do an experiment where you counter the entire gravitational force of an enormous celestial body like the Earth. Right, take a small kitchen magnet and use it to hold up a nail, and think about what's happening there, right, You have the nail is being pulled down by every single rock in the Earth. It's pulling with all of its gravity. But a tiny little kitchen magnet totally overcomes that.

Well, I think you can do that experiment. Nothing's going to happen because gravity is so weak. Right. You don't see two apples like pulling themselves together on the counter, right, And though built in apple collider, you know the apples are not drawn to each other. Gravity is a super weak force, and you can see this yourself. Right, you can do an experiment where you counter the entire gravitational force of an enormous celestial body like the Earth. Right, take a small kitchen magnet and use it to hold up a nail, and think about what's happening there, right, You have the nail is being pulled down by every single rock in the Earth. It's pulling with all of its gravity. But a tiny little kitchen magnet totally overcomes that.

It can lift a nail even though it's pulling, it's being pulled down by the whole entire planet Earth.

It can lift a nail even though it's pulling, it's being pulled down by the whole entire planet Earth.

Right exactly. Now, imagine a magnet the size of the Earth, right, I mean that would be that would be extraordinarily powerful. And so you have basically like a gravitational blob the size of the Earth still pretty ineffective compared to electromagnetism.

Right exactly. Now, imagine a magnet the size of the Earth, right, I mean that would be that would be extraordinarily powerful. And so you have basically like a gravitational blob the size of the Earth still pretty ineffective compared to electromagnetism.

Mmmm, so it's weak if you sort of compare it by object, Like you said, if you take a proton and put an extra proton, the force are going to feel from electromagnetism is so much bigger than the force of gravity. They're going to feel towards each other the same with like two electrons or two quarks and things. So in the scale of like the particles that we know, it's.

Mmmm, so it's weak if you sort of compare it by object, Like you said, if you take a proton and put an extra proton, the force are going to feel from electromagnetism is so much bigger than the force of gravity. They're going to feel towards each other the same with like two electrons or two quarks and things. So in the scale of like the particles that we know, it's.

A really weak force, that's right, exactly, And yet and yet it seems to dominate, right. That's a bit of a puzzle, Like, on one hand, it's super duper weak, and we're telling you that it hardly counts for anything. On the other hand, it's responsible for the structure of the Solar System, man for the galaxy, and it's the reason the universe looks the way it is, right, right, And so that can be confusing to people, Like how do you reconcile those two things in your head?

A really weak force, that's right, exactly, And yet and yet it seems to dominate, right. That's a bit of a puzzle, Like, on one hand, it's super duper weak, and we're telling you that it hardly counts for anything. On the other hand, it's responsible for the structure of the Solar System, man for the galaxy, and it's the reason the universe looks the way it is, right, right, And so that can be confusing to people, Like how do you reconcile those two things in your head?

Yeah, Like, why doesn't the Earth feel an electromagnetic force with the Sun, which it would be so much bigger than the force of gravity.

Yeah, Like, why doesn't the Earth feel an electromagnetic force with the Sun, which it would be so much bigger than the force of gravity.

Yeah, Well, it would be pretty shocking, And that's actually the reason is gravity is different from the other forces and that it can't be canceled out. Right, if there was some huge electrostatic difference between the Sun and the Earth, like a bunch of positive charges there and a bunch of negative charges here, it would create such an enormous force that it would be very quickly balanced. Like that's what lightning is. Right. When there's a charge differential between clouds and the grounds, it doesn't take that much before those charges want to rearrange themselves to a lower energy configuration. They rush down to the ground, or they'd rush up to the clouds, or they jump the cloud cloud to balance themselves out. Because you have two kinds of charges, you have positive and you have negative, so you can find an arrangement where basically everybody's happy. It's an equilibrium, right, But that's not true for gravity.

Yeah, Well, it would be pretty shocking, And that's actually the reason is gravity is different from the other forces and that it can't be canceled out. Right, if there was some huge electrostatic difference between the Sun and the Earth, like a bunch of positive charges there and a bunch of negative charges here, it would create such an enormous force that it would be very quickly balanced. Like that's what lightning is. Right. When there's a charge differential between clouds and the grounds, it doesn't take that much before those charges want to rearrange themselves to a lower energy configuration. They rush down to the ground, or they'd rush up to the clouds, or they jump the cloud cloud to balance themselves out. Because you have two kinds of charges, you have positive and you have negative, so you can find an arrangement where basically everybody's happy. It's an equilibrium, right, But that's not true for gravity.

Okay, I get it. So for example, if the Earth was every particle on Earth had a positive electromagnetic charge, and every particle in the Sun had a negative electromagnetic charge, there would be a humongous pull from electromagnetism, pulling the Earth into the Sun.

Okay, I get it. So for example, if the Earth was every particle on Earth had a positive electromagnetic charge, and every particle in the Sun had a negative electromagnetic charge, there would be a humongous pull from electromagnetism, pulling the Earth into the Sun.

Yeah, we'd be toased pretty quick Yeah.

Yeah, we'd be toased pretty quick Yeah.

Yeah, would be huge. Even the opposite. If we were all positive and the Sun was all positive, we would get shot out of the Solar system very quickly.

Yeah, would be huge. Even the opposite. If we were all positive and the Sun was all positive, we would get shot out of the Solar system very quickly.

That's right. And that's why you know, early days of the Solar system being formed, you have these gases and the gas and dust coalescing and very rapidly things neutralize, right, because anything that feels an electrostatic force to something else is going to find the opposite charge and they're going to coalesce and they're going to make something neutral. Right. That's why most of the things around you are neutral, right, Most of the elements are neutral, because any deviation from neutral results in a powerful force to neutralize it.

That's right. And that's why you know, early days of the Solar system being formed, you have these gases and the gas and dust coalescing and very rapidly things neutralize, right, because anything that feels an electrostatic force to something else is going to find the opposite charge and they're going to coalesce and they're going to make something neutral. Right. That's why most of the things around you are neutral, right, Most of the elements are neutral, because any deviation from neutral results in a powerful force to neutralize it.

So, thankfully the Earth is made out of both like equal amounts of positive and negative particles, right, that's right. Thankfully we're sort of balanced electromagnetically, and so even if the Sun was all positive, we would look like neutral, like a neutral ball to the Sun.

So, thankfully the Earth is made out of both like equal amounts of positive and negative particles, right, that's right. Thankfully we're sort of balanced electromagnetically, and so even if the Sun was all positive, we would look like neutral, like a neutral ball to the Sun.

Yeah, that's right. Where on large scales the Earth is neutral, right, I mean, there might be some residual positive or negative charge depending on the solar wind, et cetera. But basically the Earth is neutral, and so the largest force of the Earth feels is the gravity from the sun, even though gravity is super duper weak, right, it doesn't take a lot to counteract gravity. But it's the only player left because everybody else is sort of pair it up and danced off for the night, and gravity's just there left, hold in the bag. And gravity can't be balanced, right. You feel gravity if you have any mass. Right, there's only positive masses, no such thing as a negative mass to give anti gravity.

Yeah, that's right. Where on large scales the Earth is neutral, right, I mean, there might be some residual positive or negative charge depending on the solar wind, et cetera. But basically the Earth is neutral, and so the largest force of the Earth feels is the gravity from the sun, even though gravity is super duper weak, right, it doesn't take a lot to counteract gravity. But it's the only player left because everybody else is sort of pair it up and danced off for the night, and gravity's just there left, hold in the bag. And gravity can't be balanced, right. You feel gravity if you have any mass. Right, there's only positive masses, no such thing as a negative mass to give anti gravity.

Wow, well, let's keep going, but first let's take a quick break. Okay, So that's how gravity is so much weaker than the other forces. So how's it different than the other three forces of nature?

Wow, well, let's keep going, but first let's take a quick break. Okay, So that's how gravity is so much weaker than the other forces. So how's it different than the other three forces of nature?

There's like no end to waste. The gravity is weird, you know, there's no end to like the puzzles of gravity is fascinating.

There's like no end to waste. The gravity is weird, you know, there's no end to like the puzzles of gravity is fascinating.

Bottomless pit.

Bottomless pit.

That's right, it's a black hole of questions. And one of my favorites is just that we have no way to sort of fit gravity in with the way the universe works according to everything else. You know, we talked earlier about how we have particles and we have forces or quantum fields equivalently, and that's a really successful way to describe the universe. You know, we have the Large Hadron Collider to explore these things really high energies. And we've understood all sorts of things using this theory, but that theory is used as quantum mechanics. So the way we describe interactions, you know, the way we talk about two electrons repelling each other, or the way lightning is formed or anything, involves passing quantum particles back and forth. And that's just not true for gravity.

That's right, it's a black hole of questions. And one of my favorites is just that we have no way to sort of fit gravity in with the way the universe works according to everything else. You know, we talked earlier about how we have particles and we have forces or quantum fields equivalently, and that's a really successful way to describe the universe. You know, we have the Large Hadron Collider to explore these things really high energies. And we've understood all sorts of things using this theory, but that theory is used as quantum mechanics. So the way we describe interactions, you know, the way we talk about two electrons repelling each other, or the way lightning is formed or anything, involves passing quantum particles back and forth. And that's just not true for gravity.

What does that mean? Passing particles back and forth? Like when like if I have two magnets and they're attracted to each other, they're not. They're not It's not like an invisible telekinesis pulling on each other. They're actually swapping particles, and I can see that is that kind of what do you mean?

What does that mean? Passing particles back and forth? Like when like if I have two magnets and they're attracted to each other, they're not. They're not It's not like an invisible telekinesis pulling on each other. They're actually swapping particles, and I can see that is that kind of what do you mean?

That's exactly what I mean. That the way two things interact via some force is by exchanging particles. And so for example, electromagnetism, right, is the force behind a magnet. And the way electromagnetism works, we think at a sort of microscopic particle level, is that there's a particle that transmits that force, that sends sort of the information back and forth between two things that are feeling it and in the case of electromagnetism, that particle is the photon. Right, the particle is also a packet of light. So each of the quantum forces that we talked about before, electromagnetism, the weak force and the strong force, each of them have a particle we associate with it. And that's not just like some name tag we put on and say, hey, you get this one, you get this one. We think that that's the particle that's responsible for making the force work. So when two electrons come near each other, how do they repel each other? How does that actually happen? Well, we think that they send photons out right, the electric field of a moving electron, right, and accelerating electron generates photons, and those photons interact with the other electrons, and so basically the passing messages back and forth using these quantum particles.

That's exactly what I mean. That the way two things interact via some force is by exchanging particles. And so for example, electromagnetism, right, is the force behind a magnet. And the way electromagnetism works, we think at a sort of microscopic particle level, is that there's a particle that transmits that force, that sends sort of the information back and forth between two things that are feeling it and in the case of electromagnetism, that particle is the photon. Right, the particle is also a packet of light. So each of the quantum forces that we talked about before, electromagnetism, the weak force and the strong force, each of them have a particle we associate with it. And that's not just like some name tag we put on and say, hey, you get this one, you get this one. We think that that's the particle that's responsible for making the force work. So when two electrons come near each other, how do they repel each other? How does that actually happen? Well, we think that they send photons out right, the electric field of a moving electron, right, and accelerating electron generates photons, and those photons interact with the other electrons, and so basically the passing messages back and forth using these quantum particles.

So gravity is weird because we don't know that there is a quantum particle being exchanged when two things get attracted gravitationally.

So gravity is weird because we don't know that there is a quantum particle being exchanged when two things get attracted gravitationally.

That's right, So we have this great framework. We say, oh, maybe all forces are quantum mechanical fields interacting with each other. Right, Let's apply that to the electromagnetic field. Yeah, it works. Let's apply that to the weak force. Yeah it works. Let's apply to the strong force. Ooh, cool, it works. Maybe this is something deep about the way the universe works. Let's apply it to gravity. Uh. Oh, it doesn't work right, So what does that mean? What does it mean when I say it doesn't work? Well? For a theory to work, it has to provide predictions for experiments. You have to be able to say, okay, theory, what would happen in this configuration if I shot a proton and another particle. Predict what would happen, and then you can often do the experiments and compare it right. Well, when you do that for gravity, you try to form a quantum theory of gravity, it doesn't work. You get nonsense answers. You get answers like infinity right, or things disappear, or it just it doesn't mathematically function Like, there's no way to build a theory of gravity that we've discovered so far that works, that actually explains the way these things happen. There are a few candidates out there there pretty far from being a functional theory of quantum gravity, things like loop quantm gravity or string theory, but the basic problem is that quantum mechanics and general relativity, which is our best theory of gravity, do not play well together and we have no functioning quantum theory of gravity.

That's right, So we have this great framework. We say, oh, maybe all forces are quantum mechanical fields interacting with each other. Right, Let's apply that to the electromagnetic field. Yeah, it works. Let's apply that to the weak force. Yeah it works. Let's apply to the strong force. Ooh, cool, it works. Maybe this is something deep about the way the universe works. Let's apply it to gravity. Uh. Oh, it doesn't work right, So what does that mean? What does it mean when I say it doesn't work? Well? For a theory to work, it has to provide predictions for experiments. You have to be able to say, okay, theory, what would happen in this configuration if I shot a proton and another particle. Predict what would happen, and then you can often do the experiments and compare it right. Well, when you do that for gravity, you try to form a quantum theory of gravity, it doesn't work. You get nonsense answers. You get answers like infinity right, or things disappear, or it just it doesn't mathematically function Like, there's no way to build a theory of gravity that we've discovered so far that works, that actually explains the way these things happen. There are a few candidates out there there pretty far from being a functional theory of quantum gravity, things like loop quantm gravity or string theory, but the basic problem is that quantum mechanics and general relativity, which is our best theory of gravity, do not play well together and we have no functioning quantum theory of gravity.

So does that mean that we don't have the right theory or is that gravity is just not quantum in nature?

So does that mean that we don't have the right theory or is that gravity is just not quantum in nature?

That's exactly the question we don't know the answer to. Right In one hundred years from now, somebody will know the answer to that, I hope, and they'll look back and they'll wonder, you know, why did those guys see the clues? But we don't know. It could be that there is a quantum theory gravity, we're just not smart enough to think it up yet, right, Like the right person hasn't been born yet to put the math together, or maybe it requires a different kind of math that we're using. Right, there's some assumption we're making that's a mistake.

That's exactly the question we don't know the answer to. Right In one hundred years from now, somebody will know the answer to that, I hope, and they'll look back and they'll wonder, you know, why did those guys see the clues? But we don't know. It could be that there is a quantum theory gravity, we're just not smart enough to think it up yet, right, Like the right person hasn't been born yet to put the math together, or maybe it requires a different kind of math that we're using. Right, there's some assumption we're making that's a mistake.

Or maybe just giving it a wrong name, like maybe it should be gravit tunis or gravitinos gravitas. That's taken exactly.

Or maybe just giving it a wrong name, like maybe it should be gravit tunis or gravitinos gravitas. That's taken exactly.

That's definitely the problem. That's step number one, when we made a mistake in step number one, when we could define the particle. The other option, of course, is that maybe gravity is not a quantum force the way the other forces are. Right. The other forces we call them quantum forces because they're well described by quantum mechanics. But gravity is kind of different. I mean, the current theory we have a gravity general relativity. It doesn't like to describe gravity as a force, right, describes gravity instead as a bending of space. It says that when you have mass somewhere in space, space no longer becomes straight, becomes bent. Right, things move in curves and circles.

That's definitely the problem. That's step number one, when we made a mistake in step number one, when we could define the particle. The other option, of course, is that maybe gravity is not a quantum force the way the other forces are. Right. The other forces we call them quantum forces because they're well described by quantum mechanics. But gravity is kind of different. I mean, the current theory we have a gravity general relativity. It doesn't like to describe gravity as a force, right, describes gravity instead as a bending of space. It says that when you have mass somewhere in space, space no longer becomes straight, becomes bent. Right, things move in curves and circles.

And it's not like an actual just a mathematical nuance or a mathematical perspective. What really confirms is it is the idea that gravity can affect things that don't have mass. Right, That's how we know it's more than just a force between things that have mass. It actually like affects space for things that don't have mass.

And it's not like an actual just a mathematical nuance or a mathematical perspective. What really confirms is it is the idea that gravity can affect things that don't have mass. Right, That's how we know it's more than just a force between things that have mass. It actually like affects space for things that don't have mass.

Right, that's exactly right. So if you shoot a photon through space that has mass nearby, the photon will not move in what we consider to be a straight line, right, It'll find a path through this bent space that involves basically curving. And this is what Einstein predicted with his theory, and they saw it, you know, and you can see in space. It's called gravitational lensing. You can see photons get bent by heavy objects, and it's because, as you say, the heavy objects are bending space itself.

Right, that's exactly right. So if you shoot a photon through space that has mass nearby, the photon will not move in what we consider to be a straight line, right, It'll find a path through this bent space that involves basically curving. And this is what Einstein predicted with his theory, and they saw it, you know, and you can see in space. It's called gravitational lensing. You can see photons get bent by heavy objects, and it's because, as you say, the heavy objects are bending space itself.

Right, It's not like gravity is pulling the photon because the photon doesn't have any mass.

Right, It's not like gravity is pulling the photon because the photon doesn't have any mass.

Right, that's right, the photon doesn't have any mass.

Right, that's right, the photon doesn't have any mass.

Yeah, So that's how it's different. Like gravity seems to affect things that don't have sort of its fundamental property, you know, like electrominetic forces can affect something that does not have an electric charge.

Yeah, So that's how it's different. Like gravity seems to affect things that don't have sort of its fundamental property, you know, like electrominetic forces can affect something that does not have an electric charge.

That's true.

That's true.

Gravity can affect thing everything else, right.

Gravity can affect thing everything else, right.

Yeah, that's a pretty deep insight there, Not that for a cartoonist, not at all. Yeah, that's a fascinating way to think about it. I think that's totally correct. Yeah. And so if gravity is instead of being a force, if it's a way we change the shape of space itself, then maybe that's why we don't have a quantum theory of it. Right. And that's amazing and it's fantastic and it's exciting. And another reason why we have a hard time bringing these two things together is that quantum mechanics, the theory we've developed only works so far in flat space. That is if there's really heavy stuff nearby, we don't know how to do those quantum calculations. We can basically only do quantum mechanics in places where there isn't really strong gravity.

Yeah, that's a pretty deep insight there, Not that for a cartoonist, not at all. Yeah, that's a fascinating way to think about it. I think that's totally correct. Yeah. And so if gravity is instead of being a force, if it's a way we change the shape of space itself, then maybe that's why we don't have a quantum theory of it. Right. And that's amazing and it's fantastic and it's exciting. And another reason why we have a hard time bringing these two things together is that quantum mechanics, the theory we've developed only works so far in flat space. That is if there's really heavy stuff nearby, we don't know how to do those quantum calculations. We can basically only do quantum mechanics in places where there isn't really strong gravity.

So wait, it's a quantum physics doesn't work in reality basically? Is that what you're saying? Like, it doesn't work in the space that we actually live in.

So wait, it's a quantum physics doesn't work in reality basically? Is that what you're saying? Like, it doesn't work in the space that we actually live in.

Well, it works basically everywhere except for close to black holes. M Right. You need basically a black hole have enough gravity to break down quantum mechanics because it's when when space gets really distorted that you start to see the effects of gravity on space, and then it becomes comparable to the strength of other stuff, and that's when that's when quantum mechanics breaks down. Yeah, quantum quantum field theory works basically what we call flat space, whereas gravity bends space.

Well, it works basically everywhere except for close to black holes. M Right. You need basically a black hole have enough gravity to break down quantum mechanics because it's when when space gets really distorted that you start to see the effects of gravity on space, and then it becomes comparable to the strength of other stuff, and that's when that's when quantum mechanics breaks down. Yeah, quantum quantum field theory works basically what we call flat space, whereas gravity bends space.

Wow, so earlier when we categorize gravity as part of these four fundamental forces, maybe that's just the wrong approach. Maybe you know, do you know what I mean? Like, maybe we shouldn't be categorizing these four things as one category of quote forces.

Wow, so earlier when we categorize gravity as part of these four fundamental forces, maybe that's just the wrong approach. Maybe you know, do you know what I mean? Like, maybe we shouldn't be categorizing these four things as one category of quote forces.

That's right. It could be could be that there is no quantum theory of gravity as a fundamental force because it isn't one. Yeah, and it's just a feature of space, right, Absolutely, it's one possible explanation. But then we still need a way to make quantum mechanics work in bent space, right, And we still need to understand how to make our theory of general relativity play well with quantum mechanics, because we think quantum mechanics describes the universe, right, and general relativity is not a quantized theory. It's it's continuous, right. It treats space and everything as if it's infinitely divisible, right, it's not a quantum theory at all, in fact that it came about before quantum mechanics was even invented. And so while the basic tenets of it how it distorted space are probably correct, i mean, been verified to zillion degrees of accuracy, it doesn't feel like it can be a fundamental description of nature because it's not quantum mechanical.

That's right. It could be could be that there is no quantum theory of gravity as a fundamental force because it isn't one. Yeah, and it's just a feature of space, right, Absolutely, it's one possible explanation. But then we still need a way to make quantum mechanics work in bent space, right, And we still need to understand how to make our theory of general relativity play well with quantum mechanics, because we think quantum mechanics describes the universe, right, and general relativity is not a quantized theory. It's it's continuous, right. It treats space and everything as if it's infinitely divisible, right, it's not a quantum theory at all, in fact that it came about before quantum mechanics was even invented. And so while the basic tenets of it how it distorted space are probably correct, i mean, been verified to zillion degrees of accuracy, it doesn't feel like it can be a fundamental description of nature because it's not quantum mechanical.

So, like we want to call it a force because it seems to move things like all the other forces, but it's maybe it's not a force. Maybe it's just kind of like some other weird property of space.

So, like we want to call it a force because it seems to move things like all the other forces, but it's maybe it's not a force. Maybe it's just kind of like some other weird property of space.

Yeah, exactly. You know, maybe we've been trying to put a round peg into a square hole all these years.

Yeah, exactly. You know, maybe we've been trying to put a round peg into a square hole all these years.

A gravity peg in a quantum hole.

A gravity peg in a quantum hole.

That's right, that's right. And there are other ways that people are trying to solve this problem. Like one way is thinking that maybe gravity is a fundamental force, but it just works a little bit differently from the other forces. For example, people think about how the universe might have additional spatial dimensions, you know, like instead of just being able to move in three directions, maybe there's like four or five six dimensions that you can move in. And folks who are interested in that should listen to our podcast on extra dimensions.

That's right, that's right. And there are other ways that people are trying to solve this problem. Like one way is thinking that maybe gravity is a fundamental force, but it just works a little bit differently from the other forces. For example, people think about how the universe might have additional spatial dimensions, you know, like instead of just being able to move in three directions, maybe there's like four or five six dimensions that you can move in. And folks who are interested in that should listen to our podcast on extra dimensions.

No.

No.

Yeah, we did a whole episode on extra dimensions, but we didn't sort of get into this particular topic. So tell us how extra dimensions might explain why gravity is so weak.

Yeah, we did a whole episode on extra dimensions, but we didn't sort of get into this particular topic. So tell us how extra dimensions might explain why gravity is so weak.

Yeah. The idea is that maybe gravity isn't so weak. Maybe gravity is just as strong as all the other forces. But if there's a whole other set of dimensions out there that's ways directions that think can move, it might be that gravity is the only thing that feels those dimensions, right. It might be that those dimensions are invisible to electromagnetism and to the weak force into the strong force, but to gravity, and what that means is that gravity might be basically leaking out into those other dimensions. You know, we talked about how the farther away you get from something, the weaker the forces. So like Mercury feels the force of the Sun's gravity much more strongly than Pluto does. Right, irrelevanti of whether or not you call it a planet, it doesn't feel gravity very strongly. And that's because it's further from the Sun, right. I mean that goes like one over are squared or are is the distance it's one of our squared because we have three dimensions. If we had six dimensions, it would be one over R five, right, which falls much more rapidly. So if there are additional dimensions out there, okay, and only gravity feels them, then that might be the reason why gravitational force falls so quickly. Maybe gravity's actually just as strong as everything else when you get really really close, But then these extra dimensions exist, and most of gravity leaks out into those other dimensions.

Yeah. The idea is that maybe gravity isn't so weak. Maybe gravity is just as strong as all the other forces. But if there's a whole other set of dimensions out there that's ways directions that think can move, it might be that gravity is the only thing that feels those dimensions, right. It might be that those dimensions are invisible to electromagnetism and to the weak force into the strong force, but to gravity, and what that means is that gravity might be basically leaking out into those other dimensions. You know, we talked about how the farther away you get from something, the weaker the forces. So like Mercury feels the force of the Sun's gravity much more strongly than Pluto does. Right, irrelevanti of whether or not you call it a planet, it doesn't feel gravity very strongly. And that's because it's further from the Sun, right. I mean that goes like one over are squared or are is the distance it's one of our squared because we have three dimensions. If we had six dimensions, it would be one over R five, right, which falls much more rapidly. So if there are additional dimensions out there, okay, and only gravity feels them, then that might be the reason why gravitational force falls so quickly. Maybe gravity's actually just as strong as everything else when you get really really close, But then these extra dimensions exist, and most of gravity leaks out into those other dimensions.

Oh, sort of like between you and me, there's not just the three dimensions between you and me Ei, there are other secret hidden spaces kind of between you and me. Are these other dimensions.

Oh, sort of like between you and me, there's not just the three dimensions between you and me Ei, there are other secret hidden spaces kind of between you and me. Are these other dimensions.

Exactly other ways for gravity to spread out, all right.

Exactly other ways for gravity to spread out, all right.

And so gravity would be like just as strong as all the other forces. But it's just flessing its muscles in these other spaces that we can't see or feel exactly.

And so gravity would be like just as strong as all the other forces. But it's just flessing its muscles in these other spaces that we can't see or feel exactly.

It's like, you know, if somebody's at the center of a crowd and they let go a really stinky far right, the people next to them they smell it strongly, and the people further away they smell it much more weakly, and people outside don't smell it at all.

It's like, you know, if somebody's at the center of a crowd and they let go a really stinky far right, the people next to them they smell it strongly, and the people further away they smell it much more weakly, and people outside don't smell it at all.

All right, now imagine the farts really suddenly. But let's let's let's go with it.

All right, now imagine the farts really suddenly. But let's let's let's go with it.

Hey, I'm trying to make this successible. You know, this is something everybody canna.

Hey, I'm trying to make this successible. You know, this is something everybody canna.

Appreciate trying to make way, I get it cut it.

Appreciate trying to make way, I get it cut it.

But if there was somewhere else for that far to go, you know, if it could move not just sideways, but also could float up right, so you had a really tall room in the far floated up, then people wouldn't feel it as much because most of the far would dissipate into the upper corners of the room. And so gravity might be the same way. It might be that you know, for the first millimeters, so the first centimeters, so gravity gets very weak, very quickly. It falls off really rapidly, and that then you know, at normal distances like a meter or ten meters or whatever, you don't feel those other dimensions anymore because the other dimensions only activate it really really short distances. This is the theory people came up with, and we don't know if it's real. You know, we tested it so far. It seems like gravity works the same way for galactic scales and for earth scales, and for microscopic scales. It seems to always fall off at the same rate as a function of distance. So nobody's ever seen any evidence of these extra dimensions. But it's a fascinating theory and it's you know, it's one that would give kind of a natural explanation for why gravity would fall off so quickly and why gravity is so weak. It wouldn't explain all these other things.

But if there was somewhere else for that far to go, you know, if it could move not just sideways, but also could float up right, so you had a really tall room in the far floated up, then people wouldn't feel it as much because most of the far would dissipate into the upper corners of the room. And so gravity might be the same way. It might be that you know, for the first millimeters, so the first centimeters, so gravity gets very weak, very quickly. It falls off really rapidly, and that then you know, at normal distances like a meter or ten meters or whatever, you don't feel those other dimensions anymore because the other dimensions only activate it really really short distances. This is the theory people came up with, and we don't know if it's real. You know, we tested it so far. It seems like gravity works the same way for galactic scales and for earth scales, and for microscopic scales. It seems to always fall off at the same rate as a function of distance. So nobody's ever seen any evidence of these extra dimensions. But it's a fascinating theory and it's you know, it's one that would give kind of a natural explanation for why gravity would fall off so quickly and why gravity is so weak. It wouldn't explain all these other things.

But in fact, people sort of try to use gravity to see if there are other dimensions, right.

But in fact, people sort of try to use gravity to see if there are other dimensions, right.

Yeah, that's right. It would be a really cool clue, right if And that's a fascinating way that science has done. You know, you try to look at everything around you and see if you can fit it all into one framework. Can I use this one set of ideas to describe everything right onto one part of concepts? Yep, that's right in my fart theory of the universe. The best possible way I think to unravel this is to actually go visit a black hole. Because quantum mechanics and general relativity tell you very different things about what's happening inside a black hole. Right, as we said before, general relativity tells you it's an infinite testimal dot of almost infinite density. Quantum mechanics says, you know, the universe is quantized first of all, so you can't have infinite testimal dots. And also this sort of a minimum size to stuff, right, and you can't have all that stuff compressed in such a tiny little area. And so if you could see inside a black hole, you would learn a lot about gravity.