Einstein's theories were huge advances in science, but he still thought in terms of simple physical pictures: the acceleration of trains, the descent of elevators, rockets, the movement of the clock hands, and in fact the theory of relativity - which was an event that shook the world - came about as a result of two simple pictures of this kind The first image occupied Einstein's mind since he was sixteen years old, when he tried to imagine how the light rays would look to him if he could go next to them at the same speed. In the square of the speed of light, the famous equation that solved the mystery of stars.