"Vacuum Catastrophe" When looking at http://en.wikipedia.org/wiki/Vacuum_catastrophe I thought about my problem in understanding the question of virtual particles being real physical things or not. It appears to me that if the virtual particle pairs were actually real, always existing in high numbers before the next instant when they disappear and others create, there would be this great amount of mass in the universe affecting gravity. However, if the particles are not manifested as real in reality, the vacuum catastrophe is, in that way, explained. Does this resonate with you as a decent explanation for the discrepancy between the expected vacuum energy density if the quantum perturbations are not actually particles, but more of a fragment of spacetime and the uncertainty principle to you? The physical observations of the Casimir force etc. would then have to be described as field effects other than the virtual particles really being real. Perhaps these motions explained by virtual particles are just rather representations of forces and perturbation theory by which we cannot explain by any other imagined means for our theory at this time.