Sidney Bludman
Universidad de Chile, Departamento de Astronomía

"What Drives the Cosmological Acceleration?"

Resolving the dynamics of 'dark energy', requires complementing the homogeneous expansion observations with observations of the growth of cosmological fluctuations. Projected observations potentially distinguish static from dynamic 'dark energy', but distinguishing dynamic Dark Energy from Dark Gravity will require a weak lensing shear survey more ambitious than any now projected. Low-curvature modifications of Einstein gravity may also be detectable in refined observations in the solar system or in isolated galaxy clusters.