As I conjectured in a previous blog post, gravitons will be absorbed by matter-energy in its presence, causing the matter-energy to accelerate in the direction of the gravity source. In absence of matter-energy, that is, in a vacuum, the gravitons will burn into matter and anti-matter, and effectively start radiating Hawking radiation.
I'm sure Jack will have something to say about this hypothesis. To read the rest of the article, click here.