Hello, I am currently doing an essay on time and special relativity. I just have a few questions, 1) In many places, they say that time slows down when travelling very, very fast because of the image in the attachment. I understand that if the clock is moving, then the thing hitting either plate is going to have to travel further (the hypotenuse), and hence take longer, but because light always has to travel at the same speed, then time needs to slow down. But what I don't understand is why is the hitting of either plates "time", is this an analogy? If it was just a normal clock with no physical moving parts then surely this would be wrong? 2) Secondly, if a space ship was travelling at 1000 m/s in space and it had its lights on, then it maybe common sense that the light would travel at 300,001,000 m/s. But of course because the speed of light is constant, the light can not travel any faster. Would I be right to say, because of s = d/t And because the speed has gone up, then the time must increase to cancel the initial increase?