Description of supernova data in conformal cosmology without cosmological constant

We consider cosmological consequences of a conformal-invariant formulation of Einsteinʹs General Relativity where instead of the scale factor of the spatial metrics in the action functional a massless scalar (dilaton) field occurs which scales all masses including the Planck mass. Instead of the expansion of the universe we obtain the Hoyle–Narlikar type of mass evolution, where the temperature history of the universe is replaced by the mass history. We show that this conformal-invariant cosmological model gives a satisfactory description of the new supernova Ia data for the effective magnitude–redshift relation without a cosmological constant and make a prediction for the high-redshift behavior which deviates from that of standard cosmology for z>1.7.