If I am to understand correctly, light speed is the speed at which light travels through space. As I also am led to believe, our sun is some four lightyears away. I recall hearing that since it takes roughly four years for light to travel from the sun to us, the light we see during the day actually originated from the sun from four lightyears ago. That being said, in theory if the sun were destroyed (and we could ignore the gravitational effects that would create) would we continue to have light and heat for four years? Also, if any of what I heard/described above is accurate, is the sun we see from sunrise to sunset the actual, physical sun, or is it just an image? i.e. if the sun theoretically exploded and we were still intact, would we see the results immediately, or would it take some four years till we see a change?