Quote:
Originally Posted by
Zoerawrr 
Okay, Alex so far understood where this was going. He nodded his head slowly to show this.
On a train.
Table.
Light between two mirrors.
Metre apart.
6.7 nanoseconds to get from one mirror to the other and back.
And... since the train was moving, the mirrors were. Yeah... made sense. Kinda.
"Does the speed of the train matter, sir? And... maybe I'm being dim, but in my head it makes more sense for the speed to be quicker, 'cause the train is zooming along and... well, I think my brain just exploded."
There was one way to settle this.
"I don't think we should question the light, sir. After all, all things serve The Beam."
Alex didn't have a clue what he was on about.
"Well, in this case the beam serves us," Risu said, wondering why it felt wrong to say that. He plunged on quickly. "And you've asked a very good question. As your head looks curiously intact and unexploded, perhaps you have an idea of how to answer the question yourself?"
He smiled encouragingly. "Let's say the train is going at a speed of, oh, 100 kph. A hundred kilometres per hour. Now, as you seem to have realised, to the person at the station, the beam of light travels a slightly longer way because the train is moving past. What then - and if you have an answer to this, you'll have understood the entire thought experiment - if the train was going 150 kph? What would the person at the station see happen to the beam of light
then? Any ideas, Mr Miner?"