Brian Cox

I mean, they are quite big effects, these, in the sense that for the satellite navigation system, for example, GPS. The clocks on the satellites tick at a different rate to the clocks on the ground. And it's quite a big effect.

I think from memory, it's something like over 30,000 nanoseconds per day difference because they're in a weaker gravitational field and they're moving and all sorts of things. It's the same thing. But 30,000 nanoseconds. Light travels one foot per nanosecond, which is great. I always say that God used imperial units because it's 30.8 centimeters. It's one foot, right? It's good.

I think from memory, it's something like over 30,000 nanoseconds per day difference because they're in a weaker gravitational field and they're moving and all sorts of things. It's the same thing. But 30,000 nanoseconds. Light travels one foot per nanosecond, which is great. I always say that God used imperial units because it's 30.8 centimeters. It's one foot, right? It's good.

I think from memory, it's something like over 30,000 nanoseconds per day difference because they're in a weaker gravitational field and they're moving and all sorts of things. It's the same thing. But 30,000 nanoseconds. Light travels one foot per nanosecond, which is great. I always say that God used imperial units because it's 30.8 centimeters. It's one foot, right? It's good.

It's one foot per nanosecond. So that's 30,000 feet of position measurement. if you drift your clock out by 30,000 nanoseconds. So it wouldn't work. So it's a big effect for when you start using time to measure distance, which is what we do in satellite navigation, GPS. So we have to correct. So the clocks have to be corrected for that effect.

It's one foot per nanosecond. So that's 30,000 feet of position measurement. if you drift your clock out by 30,000 nanoseconds. So it wouldn't work. So it's a big effect for when you start using time to measure distance, which is what we do in satellite navigation, GPS. So we have to correct. So the clocks have to be corrected for that effect.

It's one foot per nanosecond. So that's 30,000 feet of position measurement. if you drift your clock out by 30,000 nanoseconds. So it wouldn't work. So it's a big effect for when you start using time to measure distance, which is what we do in satellite navigation, GPS. So we have to correct. So the clocks have to be corrected for that effect.

So it's an effect that we can easily measure with atomic clocks, but it doesn't make much difference to us as humans. But just the point is that the laws of nature would allow you to do it if you could go close to the speed of light. By the way, the last thing I'll say is the limiting factor. You might say, well, what happens if you go really close to the speed of light?

So it's an effect that we can easily measure with atomic clocks, but it doesn't make much difference to us as humans. But just the point is that the laws of nature would allow you to do it if you could go close to the speed of light. By the way, the last thing I'll say is the limiting factor. You might say, well, what happens if you go really close to the speed of light?

So it's an effect that we can easily measure with atomic clocks, but it doesn't make much difference to us as humans. But just the point is that the laws of nature would allow you to do it if you could go close to the speed of light. By the way, the last thing I'll say is the limiting factor. You might say, well, what happens if you go really close to the speed of light?

What happens if you go at the speed of light? Well, special relativity, Einstein's theory, is built such that the distance between any two events in the universe along the path of the beam of light between the events is zero. No time at all. So that's the way that Einstein's theory is built.

What happens if you go at the speed of light? Well, special relativity, Einstein's theory, is built such that the distance between any two events in the universe along the path of the beam of light between the events is zero. No time at all. So that's the way that Einstein's theory is built.

What happens if you go at the speed of light? Well, special relativity, Einstein's theory, is built such that the distance between any two events in the universe along the path of the beam of light between the events is zero. No time at all. So that's the way that Einstein's theory is built.

So he asked the question when he was younger, famously, what would the universe look like if I traveled alongside a beam of light? And the answer is that you wouldn't perceive any time. You can't. The last thing I'll say is that if you've got any mass at all, you can't do that. You can't go at the speed of light.

So he asked the question when he was younger, famously, what would the universe look like if I traveled alongside a beam of light? And the answer is that you wouldn't perceive any time. You can't. The last thing I'll say is that if you've got any mass at all, you can't do that. You can't go at the speed of light.

So he asked the question when he was younger, famously, what would the universe look like if I traveled alongside a beam of light? And the answer is that you wouldn't perceive any time. You can't. The last thing I'll say is that if you've got any mass at all, you can't do that. You can't go at the speed of light.

So according to our model, which is a good model and it seems to work, but if you've got no mass, you go at the speed of light. So if you're a photon, you go at the speed of light and no time. So...

So according to our model, which is a good model and it seems to work, but if you've got no mass, you go at the speed of light. So if you're a photon, you go at the speed of light and no time. So...

So according to our model, which is a good model and it seems to work, but if you've got no mass, you go at the speed of light. So if you're a photon, you go at the speed of light and no time. So...

Yeah, that's called the – I can never pronounce it. It's the albacore – what's it called? The drive. So you can – Einstein's general theory of relativity, general relativity is his theory of gravity. And it's a theory where space and time are distorted by things, anything in the universe, right? Stars and planets. So that's what gravity is. It's the distortion of space and time by mass and energy.