  The Planck mass and the cosmological constant determine the minimum and the
maximum distances in the physical universe. A relativistic theory that takes
into account a fundamental distance limit $\ell$ on par with the fundamental
speed limit $c$, is based on the de Sitter extension of the Lorentz symmetry.
This article proposes a new de Sitter gauge theory of gravity which allows the
consistent cosmological evolution of the $\ell$. The theory is locally
equivalent to Dirac's scale-invariant version of general relativity, and
suggests a novel non-singular extension of cosmology.
