Sean Carroll is a physicist at the California Institute of Technology. He received his Ph.D. in 1993 from Harvard University. His research focuses on theoretical physics and cosmology, especially the origin and constituents of the universe. He has contributed to models of interactions between dark matter, dark energy, and ordinary matter; alternative theories of gravity; and violations of fundamental symmetries. Carroll is the author of The Particle at the End of the Universe, From Eternity to Here: The Quest for the Ultimate Theory of Time, and Spacetime and Geometry: An Introduction to General Relativity. He has been awarded fellowships by the Sloan Foundation, Packard Foundation, and the American Physical Society, as well as the MIT Graduate Student Council Teaching Award and the Villanova University Arts and Sciences Alumni Medallion. Carroll has appeared on TV shows such as The Colbert Report and Through the Wormhole with Morgan Freeman, and frequently serves as a science consultant for film and television. He lives in Los Angeles with his wife, writer Jennifer Ouellette.