Brian Cox

Yeah. Wow. But those are models. I mean, it's important to say that it's interesting because until... So we have a hypothesis, which is strongly supported by lots of bits of evidence, that dark matter is some kind of particle. So that's the broadly, that's what you find in the textbooks. But it's true that until you find it, until you see it, then you haven't shown it to be correct.

Yeah. Wow. But those are models. I mean, it's important to say that it's interesting because until... So we have a hypothesis, which is strongly supported by lots of bits of evidence, that dark matter is some kind of particle. So that's the broadly, that's what you find in the textbooks. But it's true that until you find it, until you see it, then you haven't shown it to be correct.

Are there alternative theories? There are. Are they compelling? No, they all have problems. And most of them have problems with that pattern, the CMB, the cosmic microwave background that we just saw. Because that pattern, what you're looking at actually in that pattern is acoustic, it's waves, sound waves essentially in the early universe that go through the plasma of the early universe.

Are there alternative theories? There are. Are they compelling? No, they all have problems. And most of them have problems with that pattern, the CMB, the cosmic microwave background that we just saw. Because that pattern, what you're looking at actually in that pattern is acoustic, it's waves, sound waves essentially in the early universe that go through the plasma of the early universe.

Are there alternative theories? There are. Are they compelling? No, they all have problems. And most of them have problems with that pattern, the CMB, the cosmic microwave background that we just saw. Because that pattern, what you're looking at actually in that pattern is acoustic, it's waves, sound waves essentially in the early universe that go through the plasma of the early universe.

And they go out and we know what speed they go through that plasma. So it's almost like you're looking at a pond and you're throwing stones into the pond. And they all land in the pond at the same time and send ripples out, little circular ripples in the pond. And they all overlap. And that's what that pattern is. So we're looking at sound waves going through this plasma. And those theories...

And they go out and we know what speed they go through that plasma. So it's almost like you're looking at a pond and you're throwing stones into the pond. And they all land in the pond at the same time and send ripples out, little circular ripples in the pond. And they all overlap. And that's what that pattern is. So we're looking at sound waves going through this plasma. And those theories...

And they go out and we know what speed they go through that plasma. So it's almost like you're looking at a pond and you're throwing stones into the pond. And they all land in the pond at the same time and send ripples out, little circular ripples in the pond. And they all overlap. And that's what that pattern is. So we're looking at sound waves going through this plasma. And those theories...

uh require the dark matter the dark matter fits well if it's in there in in this plasma in this kind of soup that this subatomic particle soup that's the early universe and the way the sound waves go through it fit that idea so that's one thing but the the the idea also came from looking at galaxies and how they rotate and galaxies and how they bend light and and

uh require the dark matter the dark matter fits well if it's in there in in this plasma in this kind of soup that this subatomic particle soup that's the early universe and the way the sound waves go through it fit that idea so that's one thing but the the the idea also came from looking at galaxies and how they rotate and galaxies and how they bend light and and

uh require the dark matter the dark matter fits well if it's in there in in this plasma in this kind of soup that this subatomic particle soup that's the early universe and the way the sound waves go through it fit that idea so that's one thing but the the the idea also came from looking at galaxies and how they rotate and galaxies and how they bend light and and

And deform space and time and how they interact together. So there's loads of different bits of information, observations of the universe from the cosmic microwave background all the way through to galaxies and the formation of galaxies and the theories that we have there that suggest there are these particles around that interact very weakly with light.

And deform space and time and how they interact together. So there's loads of different bits of information, observations of the universe from the cosmic microwave background all the way through to galaxies and the formation of galaxies and the theories that we have there that suggest there are these particles around that interact very weakly with light.

And deform space and time and how they interact together. So there's loads of different bits of information, observations of the universe from the cosmic microwave background all the way through to galaxies and the formation of galaxies and the theories that we have there that suggest there are these particles around that interact very weakly with light.

So they don't really interact with light at all, which is why we don't see them, which is why they're dark. That's just like a neutrino, right? So like heavy neutrinos. And actually there was a theory once that maybe they were heavy neutrinos, but that's kind of disfavored now. And so we have loads of kind of different bits that fit. This is how you do science.

So they don't really interact with light at all, which is why we don't see them, which is why they're dark. That's just like a neutrino, right? So like heavy neutrinos. And actually there was a theory once that maybe they were heavy neutrinos, but that's kind of disfavored now. And so we have loads of kind of different bits that fit. This is how you do science.

So they don't really interact with light at all, which is why we don't see them, which is why they're dark. That's just like a neutrino, right? So like heavy neutrinos. And actually there was a theory once that maybe they were heavy neutrinos, but that's kind of disfavored now. And so we have loads of kind of different bits that fit. This is how you do science.

You start with a theory and you make a load of observations and you can infer things and you get a consistent picture. But... very importantly, until you find it, until you really find that particle, then you don't know, right? So that's a good question.

You start with a theory and you make a load of observations and you can infer things and you get a consistent picture. But... very importantly, until you find it, until you really find that particle, then you don't know, right? So that's a good question.

You start with a theory and you make a load of observations and you can infer things and you get a consistent picture. But... very importantly, until you find it, until you really find that particle, then you don't know, right? So that's a good question.