Transcript:

So, most people are familiar with the prediction of special relativity, which says that the faster something moves, the slower time passes for it. There is time dilation that happens.

So, I actually calculated it. If you take Usain Bolt, he ran the fastest 100 meters. If you calculate his average speed, and you apply special relativity to it, you can calculate how much time dilated for Usain Bolt. That's the number. Time slowed down for Usain Bolt. This thing is shaking because of the wind, but don't worry about it.

There is another consequence where time moves at a different rate, depending on which gravity field you are in — which means if the space-time is more curved, which is a stronger gravity field, time will move slower for you compared to regions where space-time is more flat or less curved. You can calculate that out also.

A consequence of general relativity is that the centre of the Earth is two years younger compared to the surface of the Earth. This is amazing.