It's an interesting thought. Nothing scientific here, just my thoughts. If we assume that "consciousness" just leaves our body when we die and exists as a form of energy or sth like that and re-unites with the quantum vacuum energy, the "soul" would float through space with light speed. The interesting fact is that for anything that travels with light speed the time-dimension disappears - there's no time anymore. All those questions about eternity / nothingness are becoming obsolete