Soleron on 19 May 2009
When string theory matures we'll have a proper, quantum description of gravity that accounts for all of today's mysteries. But it's so hard that we can't even find the equations of string theory, never mind solve them.
Gravitons are a quantum analogue of classical gravitational action-at-a-distance. We can't directly observe them because of their properties and we can't incorporate them into a consistent theory because they are non-renormalisable at the moment.
