Going back to the bus example, if you were to shoot an arrow out the window at a target down the road in front of you, how fast would it be moving when it hit the bullseye? Well, essentially it would be going the speed of the bus – about 60 mph – plus however fast you shot the arrow. Now what if you shined a beam of light at it? Since the light travels at 186,000 miles per second, we would just add the 60 mph right? Wrong. Scientists found that no matter what, light travels the same speed. Which brings us to our next point…