One of Albert Einstein’s basic theorems is that of relativity, which concerns the movement of an object itself inside a moving object.
He took as an example of somebody walking in a train. While the person walking in the train thinks he is moving at his normal walking speed, an outside observer sees he is moving at the speed of the train plus his walking speed. Sometimes, when you’re inside something bigger that moves fast, it’s easy to miss what’s truly hauling you forward.