"Why is the Expansion of the Universe Accelerating?"

Professor Mustapha Ishak-Boushaki

University of Texas - Dallas

Cosmology, Relativity, and Astrophysics Group

Abstract: For more than a decade, cosmological observations indicate that the expansion of the universe is accelerating. Cosmic acceleration and the questions associated with it are at the heart of one of the most challenging and puzzling problems in cosmology and physics. What is the cause of this acceleration? Is it because of a repulsive dark energy or cosmological constant pervading the universe, or perhaps an extension to Einstein's General Relativity that takes effect at cosmological scales of distance, or because the expansion rate of space-time is uneven from one region to another in the universe? I will review these possibilities and discuss what recent results, including ours, have to say about it.

3:15 P.M., Room 104