2:30 pm Monday, 17 March 2003
Precision distance-redshift observations can map out the recent expansion history of the universe, including the present acceleration and the transition to matter dominated deceleration. The proposed Supernova/Acceleration Probe (SNAP) will determine the contribution and equation of state of the dark energy, providing insights into fundamental high energy physics theories, cosmology, and gravitation. In complementarity with Planck CMB data, SNAP can also achieve potentially 3 sigma detection of time variation in the equation of state. This is a critical clue to distinguish between various dynamical scalar field models for the dark energy, as well as higher dimension and alternate gravity theories.