The Chinese records back as far as 1054 give us information that we don't have recorded otherwise. They had spotted a Nova, a new star, in one region of the sky, and that region nowadays is the center from which we get pulses - but where does the light come from that we see there? This cloud of gas thrown out, why should gas continue to radiate energy? - because the energy has to disappear. Well, it seemed to me that it was reasonable to think of the source of the energy as contained in rotation of a star left behind in the explosion. I should have followed that up by looking for pulses of light coming from that object, but that was subsequently observed, I think if I remember right, thirty pulses a second, the indication that there is really a rotating object at the center that powers the surrounding mass of gas.