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About space and time: Part 2 of 2 The speed of light

[video]https://youtu.be/aeCsS6PjhK8[/video]


In reality, Tom's car (sadly) doesn't really go fast enough to demonstrate the effects of Lorentz contraction. How fast do you have to be moving before the effects of Lorentz contraction and time dilation do become "noticeable"? You’ll need the formulae for length contraction and time dilation, which can be found here.


At the heart of this lesson is the experimental fact that light moves at a constant speed – 299,792,458 metres per second. Because it's so incredibly fast, people used to think that light was transmitted between objects instantaneously. It wasn't until 1676 that the first measurement of light's finite speed was made by Danish astronomer Ole Rømer. In this video, Professor Brian Cox talks about this measurement and its implications for the nature of the universe. This video