Christoph Wetterich

Dark Energy - a Cosmic Mystery

Dark energy - a homogeneously distributed cosmic energy density - seems to explain various cosmological observations. The anisotropies in the microwave background radiation, the formation of structure and the late time acceleration of the Hubble expansion fit into a consistent picture. The role and origin of dark energy are among the greatest mysteries in fundamental physics, touching the question of unification of gravity with the fundamental quantum interactions.

We discuss quintessence - a dynamical form of dark energy - and possible signatures distinctive from a cosmological constant. Quintessence could be related to a new "fundamental" macroscopic force and induce a small time variation of fundamental constants.