  We study the boundary terms of the spectral action of the noncommutative
space, defined by the spectral triple dictated by the physical spectrum of the
standard model, unifying gravity with all other fundamental interactions. We
prove that the spectral action predicts uniquely the gravitational boundary
term required for consistency of quantum gravity with the correct sign and
coefficient. This is a remarkable result given the lack of freedom in the
spectral action to tune this term.
