# Feynman lectures on physics: The Michelson-Morley experiment

I have a problem understanding something. I'm reading FLP and here I don't understand why when the system is travelling, the light doen't make the same angle in the mirror C... if B and C are moving straight on for me there is no reason for light to make an other angle. I'm a bit stuck there, can anyone help me?

Furthermore, as Feynman mentions in the first section, one of the consequences of Maxwell's equations is that the speed of light is independent of the motion of the source. So, there will be a difference in time taken when the entire apparatus is moving, since the light has to cover a longer distance (from the perspective of the observer) at the same velocity $c$.