  Some recent supernovae studies have extended the distance versus velocity
Hubble plot to very high redshift, and have revealed the apparent presence of a
cosmic repulsion. We show that such a repulsion has a natural origin within
conformal gravity, a fully covariant candidate alternative to standard gravity,
and that it arises from the gravitational field itself via the negative spatial
curvature which conformal cosmology is required to possess. In this same
cosmology the flatness, horizon and cosmological constant problems are all
resolved, and no need is found for dark matter.
