Brian Cox
speaker
1,719 appearances
13 recordings
8 series
first heard Oct 2024
last heard 16 Jun
Brian Cox’s voice in public audio — every appearance, attributed to the second.
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recordings per month · last 12 monthsRecordings per month over the last 12 months — 9 in all, peaking in Jun 2026 with 3.
Appearances
Because the study of black holes and this idea of information and how does it get out, that's leading us to suspect that space and time themselves are not fundamental, but they emerge from something else. So just in the way that we've been talking about consciousness. emerging from this physical structure in our heads.
So we don't know how it emerges, it's a very strange thing, but it emerges from this collection of atoms in a particular pattern. Well, we think now, from the study of black holes, that space and time emerge from something else, which is kind of... One way to describe it is just a quantum theory. So in quantum computing terms, it would be just qubits
So a network of qubits entangled together, just like a quantum computer. Out of that, we suspect that space and time might emerge. So surely we have to understand that process, and we don't really fully understand that, but we have glimpses of it in much more detail to start talking about the origin of time. Because in order to talk about the origin of time, you have to know what it is.
And we don't actually know what it is, which is, you know, and that's kind of when you say that it sounds bizarre, doesn't it? Well, how can you not know what time is? I think Einstein once said that it is the thing that you measure on a watch. But he said that as kind of almost a joke, because you assume in Einstein's theory, there's a thing that the watch measures.
But what actually it is at the deepest level is a good question. But it's interesting the study of black holes is forcing us towards these theories. It's not that we had the theories face and time emerging from something and decided we could check it by thinking about black holes. It's come the other way around, really. So it's interesting. But that almost makes...
the universe look in some ways like a giant quantum computer, which is not to say that we live in a simulation, before you ask. But it just looks like there's a description of the universe that looks like a quantum computer type description. That doesn't have the concept of space or time in it.
It is. It's interesting that you're right. And that's a good way of phrasing it. It mimics or looks like a network of qubits. So it looks like some kind of quantum computing description is available to us, to the universe. But I don't think you can infer much from that. I mean, it just passes the question further back.
As I said, we have never understood what it means for the universe to have a beginning. So we don't really know that. And so this is the same. I think it's just the same question. It's like, well, you ask, well... If it really is a network of qubits, it could have been there forever, that network of qubits. Actually, in quantum theory, it's more natural for it to be just eternal.
And it's an interesting question. I once gave a talk, actually, a conference of bishops. They were Catholic bishops. And they asked me to go and give a talk at their conference about cosmology. And so I gave the talk about cosmology, and they all listened. And we had a question thing afterwards. And I said to them, What happens if we discover the universe has always existed? Because it might have.
We know there's a thing called the Big Bang, but it might have been something that happened in a pre-existing universe. Maybe that's eternal. What does that mean for your sort of picture of a creator? Does it? I don't know. I was asking it. It's a genuine question. Right. How would you? And they really didn't. They thought it was a cool question and didn't have an answer. Right. But it but it is.
I think the idea that I was the question to you, actually, are we more comfortable with the universe that began or would we be more comfortable with the universe that had always existed?
And you're right. You've had Sean Carroll on the show. He always points out that this question, why is there something rather than nothing, presupposes that nothing is more likely than something.
Whereas it might be the other way around. Right, right. We don't even know that. Right.
That's the big one. The history, I think historically, you have, I think it's right to say that Einstein really felt, I think, that initially that an eternal universe was more natural. But it is also true to say that his theory, general relativity, really doesn't quite rule that out. But it's strongly suggestive of there being a beginning and or an end.
So the theory itself, historically speaking, strongly suggests that. And so he changed his mind. And then we saw the universe was expanding. We observed that. And then we've now seen the oldest light in the universe, the cosmic microwave background radiation, which is the afterglow of the Big Bang. So we know that the universe was hot and dense 13.8 billion years ago.
We have so much evidence for that, not least that we have a photograph of it 380,000 years after the Big Bang. It's called the cosmic microwave background radiation. Let's see that images of that. That's from the satellite called Planck, a European satellite and also satellite called COBE. So we have these images of the afterglow of the Big Bang.
We also have theories that tell us about the abundance of chemical elements in the universe which match this perfectly. So there's multiple lines of evidence that tell us the universe was hot and dense. But none of that tells us that that was the beginning. I think that would be widely accepted. It's a beginning in Einstein's theory.
If you just take general relativity, there's a singularity there at the beginning of time. We don't know what it is, but it's there. But it absolutely is true to say that we think that's not complete as a picture. So there it is. So that is light that was emitted about 380,000 years after the Big Bang.
And the key thing, there's so many things to say about these images, but one thing is those colours. correspond to regions of very slightly different density that we detected now in the gases of the young universe.
Yeah, the reds and blues, all those as well. They're both the same. So that greeny one, well, either that one or the one with the greeny blue, that one, that's from the Planck satellite. So those colors correspond to regions of different density.
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