November 6, 2002: Time Travel and Cosmology - Lawrence M. Krauss

Professor Lawrence M. Krauss, Ambrose Swassie Professor of Physics and chair of the physics department at Case Western Reserve University, explores the theoretical possibilities and paradoxes of time travel. This heavyweight physicist, comparable to Michio Kaku in stature, examines whether time travel could be scientifically achievable based on current understanding of physics and cosmology. Krauss addresses the fundamental question that puzzles scientists: if time travel is theoretically possible, as many leading physicists believe it may be, then where are the time travelers? The conversation delves into the complex mathematics and physics behind potential time travel mechanisms, including discussions of relativity, spacetime geometry, and quantum mechanics. Art and Krauss explore various theoretical models that might permit temporal displacement, examining the scientific literature and considering what conditions would need to exist for actual time travel to occur. The discussion addresses the famous grandfather paradox and other temporal conundrums that arise when considering backward time travel. Krauss provides rigorous scientific analysis while maintaining accessibility for general audiences, explaining how concepts from advanced physics might one day enable humanity to journey through time itself.