It seems to me that this song is about some person who is looking up at the night sky and contemplating a star that is fading out of existence or that may have gone supernova. I think the lyrics are saying that the star will be gone and that the viewer is only seeing the left over light from the star due to distance (even though the star is no longer physically present) and because of this it is making him wonder whether someone in the future could be looking at his own light so to speak, even though in that scenario he would no longer exist.
It seems to me that this song is about some person who is looking up at the night sky and contemplating a star that is fading out of existence or that may have gone supernova. I think the lyrics are saying that the star will be gone and that the viewer is only seeing the left over light from the star due to distance (even though the star is no longer physically present) and because of this it is making him wonder whether someone in the future could be looking at his own light so to speak, even though in that scenario he would no longer exist.