Okay so here is a question. I don’t need posers who just want to blow smoke out their ass trying to sound smart. This is an actual question. Is there an absolute speed of light? Does light travel at 300,000 kps no matter the conditions?
So here is your crash course in relativity. You are on a train traveling at 90mph and drop a ping pong ball onto a table. To you the ball travels straight down, and then bounces straight up. So in your perspective it hasn’t traveled any distance. However for an observer on the ground who is stationary, the ball travels forty feet between bounces. Since the train is moving, they observe distance between bounces, while you observe no lateral distance traveled. Both people are right according to their perspective.
Now if hit the ping pong ball at 10mph across the train car, to you the ball will have traveled 10mph, but to the stationary observer it will be moving at 100mph. Again according to the perspective of the observer, they are both right.
So the question arises, if you fire a laser (which moves at the speed of light) and it shoots out the front of the train, without resistance will it be moving at the speed of light only or the speed of light plus the speed of the train?
That is all the information needed for the equation. Don’t get lost in the weeds thinking of B.S. questions,(like what color is the train, or where is it headed) lets just see what you think.