[en] We discuss the possibility that spontaneous breakdown of conformal invariance due to the very existence of our universe originates all the mass (or length) scales ranging from the Planck mass (approx. 1019 GeV) to the Hubble constant (approx. 10-42 GeV) and suggest that the photon may have a curvature-dependent mass which is as small as 10-42 GeV. We also present a possible clue to Dirac's large number hypothesis. (orig.)