Hello, I've got two quick questions. Why is it so that they say "if a object moves extremely fast then we see it curtailed/shortened a little bit"? But if it moves that fast that the length even may be noticeable, how on Earth do we SEE it shortened when it moves THAT fast past us? If a spaceship flies by in the speed of light, we see nothing but a wave. I might be wrong here, I hope I am, that's why I want to know why people still say that we See it shortened. And besides, if an airplane flew by us even as slow as 1000 km/h. How much exactly does the aeroplane shorten then? I have no time to calculate, but was it less than a millimetre.. ____________________ Second problem ----------------------- Why is it so that if one twin steps on a spacecraft and goes for a flight in the speed of light and after returning his twin brother is the one who became older? I mean isn't it the same if the spaceship stays put and the whole universe went for a flight in the speed of light? Thanks for your replies.