In 1996 Haisch and Rueda published a ZPF explanation for intertial mass: http://www.calphysics.org/haisch/mercury.html
They now say they have a similar explanation for gravitational mass: http://www.eurekalert.org/pub_releases/2005-08/ns-ijv081005.php "Rueda and Haisch argued that charged matter particles such as electrons and quarks are unceasingly jiggled around by the zero-point field. If they are at rest, or travelling at a constant speed with respect to the field, then the net effect of all this jiggling is zero: there is no force acting on the particle. But if a particle is accelerating, their calculations in 1994 showed that it would encounter more photons from the quantum vacuum in front than behind it (see Diagram). This would result in a net force pushing against the particle, giving rise to its inertial mass (Physical Review A, vol 49, p 678). But this work only explained one type of mass. Now the researchers say that the same process can explain gravitational mass. Imagine a massive body that warps the fabric of space-time around it. The object would also warp the zero-point field such that a particle in its vicinity would encounter more photons on the side away from the object than on the nearer side. This would result in a net force towards the massive object, so the particle would feel the tug of gravity. This would be its gravitational mass, or weight (Annalen der Physik, vol 14, p 479). " Anyone have a Newscientist subscription to fetch the whole article? http://www.newscientist.com/article.ns?id=dn7844&feedId=online-news_rss20
