Gravity couples very weak to mass. At low energies (i.e. mass) this coupling is thus negligable and not observable relative to the other fundamental couplings in nature. In a 4 dimensional theory one expects gravity coupling to become of the same order as the others first around 10 to the 19. GeV. In a higher dimensional theory this may happen already at 10 to the 3. GeV, i.e at LHC and ATLAS. So if nature should hold unknown extra dimensions, this may be observable in a few years, making the experimental exploration of a unified theory of all fundamental couplings possible.