Brian Cox

Yeah. But we're talking the distance between the galaxies is, you know, the Andromeda galaxy is two million light years away. Right. Which is the largest and nearest large neighbor. So I think when I when I think about this, I tend to confine it to our galaxy because I can't conceive of travel between galaxies. Too crazy. I think it's too far.

Yeah. But we're talking the distance between the galaxies is, you know, the Andromeda galaxy is two million light years away. Right. Which is the largest and nearest large neighbor. So I think when I when I think about this, I tend to confine it to our galaxy because I can't conceive of travel between galaxies. Too crazy. I think it's too far.

Although for now, it is true that the laws of physics do not prevent that. So relativity, I teach relativity at Manchester University for the first years, the 18-year-olds.

Although for now, it is true that the laws of physics do not prevent that. So relativity, I teach relativity at Manchester University for the first years, the 18-year-olds.

Although for now, it is true that the laws of physics do not prevent that. So relativity, I teach relativity at Manchester University for the first years, the 18-year-olds.

And the first thing we do in special relativity is talk about the fact that if you travel close to the speed of light, so if you had a spacecraft traveling close to the speed of light, then distances shrink from your perspective.

And the first thing we do in special relativity is talk about the fact that if you travel close to the speed of light, so if you had a spacecraft traveling close to the speed of light, then distances shrink from your perspective.

And the first thing we do in special relativity is talk about the fact that if you travel close to the speed of light, so if you had a spacecraft traveling close to the speed of light, then distances shrink from your perspective.

And the one number I always have in my mind is that the Large Hadron Collider at CERN, the protons go around the ring, which is 27 kilometres in circumference, and they go around at 99.999999% the speed of light, so close to the speed of light. At that speed, distances shrink by a factor of 7,000. And so that ring... is something like four meters in diameter to the protons.

And the one number I always have in my mind is that the Large Hadron Collider at CERN, the protons go around the ring, which is 27 kilometres in circumference, and they go around at 99.999999% the speed of light, so close to the speed of light. At that speed, distances shrink by a factor of 7,000. And so that ring... is something like four meters in diameter to the protons.

And the one number I always have in my mind is that the Large Hadron Collider at CERN, the protons go around the ring, which is 27 kilometres in circumference, and they go around at 99.999999% the speed of light, so close to the speed of light. At that speed, distances shrink by a factor of 7,000. And so that ring... is something like four meters in diameter to the protons.

So according to laws of physics, if you can build a spacecraft that goes very close to the speed of light, you can shrink the distance to the Andromeda Galaxy and therefore the time it takes to get there by an arbitrary amount, actually. The closer you get to the speed of light, the more you can shrink it. And so you can make those two million light years.

So according to laws of physics, if you can build a spacecraft that goes very close to the speed of light, you can shrink the distance to the Andromeda Galaxy and therefore the time it takes to get there by an arbitrary amount, actually. The closer you get to the speed of light, the more you can shrink it. And so you can make those two million light years.

So according to laws of physics, if you can build a spacecraft that goes very close to the speed of light, you can shrink the distance to the Andromeda Galaxy and therefore the time it takes to get there by an arbitrary amount, actually. The closer you get to the speed of light, the more you can shrink it. And so you can make those two million light years.

You could traverse across that distance in principle in a minute, according to physics. However, the downside... is that you couldn't come back to tell – if you came back to the Earth at that speed to tell everybody what you'd found, at least four million years would have passed on the Earth. Oh, boy. So you can't – so there's kind of a downside to it.

You could traverse across that distance in principle in a minute, according to physics. However, the downside... is that you couldn't come back to tell – if you came back to the Earth at that speed to tell everybody what you'd found, at least four million years would have passed on the Earth. Oh, boy. So you can't – so there's kind of a downside to it.

You could traverse across that distance in principle in a minute, according to physics. However, the downside... is that you couldn't come back to tell – if you came back to the Earth at that speed to tell everybody what you'd found, at least four million years would have passed on the Earth. Oh, boy. So you can't – so there's kind of a downside to it.

We could, in principle, explore the galaxy and beyond. But getting to chat to everybody about what you found is forbidden by the structure of the universe. It's the way that relativity works. That really is essentially a time machine. Well, it's a time machine in the sense that we could go arbitrarily far into the future. by flying around in a rocket very close to the speed of light.

We could, in principle, explore the galaxy and beyond. But getting to chat to everybody about what you found is forbidden by the structure of the universe. It's the way that relativity works. That really is essentially a time machine. Well, it's a time machine in the sense that we could go arbitrarily far into the future. by flying around in a rocket very close to the speed of light.

We could, in principle, explore the galaxy and beyond. But getting to chat to everybody about what you found is forbidden by the structure of the universe. It's the way that relativity works. That really is essentially a time machine. Well, it's a time machine in the sense that we could go arbitrarily far into the future. by flying around in a rocket very close to the speed of light.