Is the speed of light constant relative to the observer? Hypothetically, I am standing at the front of a train. The train is traveling 100 mph. I shine a flashlight pointing forward in the direction the train is traveling.
Is the light from the flashlight traveling at 670,616,629 mph or (670,616,629 mph) +the speed of the train (100 mph) = 670,616,729 mph.?