Highly Warped Brane Concept The Randall/Sundrum Planck brane conjecture assumes gravitons flow freely between the bulk and our 3-D Standard Model brane. The graviton flow via the hypothetical T-quanta would be distinguished by being non-isotropic and very concentrated. In contrast, general graviton flow across the bulk/Standard Model brane-wall divide should be purely isotropic, as viewed by an observer within our brane.