According to Einstein's special theory of relativity, there is no such thing as a moment in time spread throughout the universe. Instead, time is one of four dimensions in spacetime. Learn how this "relative" view of time is usefully diagramed with light cones, representing the past and future.
00:00 - Understanding Cosmology, Gravity, and Relativity
01:00 - Taking a Four-Dimensional Viewpoint of Relativity
02:15 - Moving Into a Space-Time View of Reality
03:40 - Differences Between a Newtonian and Einsteinian View of the Universe
04:45 - The Notion of Simultaneity
05:55 - Einstein’s Clocks, Poincaré’s Maps by Peter Galison
06:05 - Recurrence Theorem
08:00 - Einstein's Clock Patents
08:45 - Constructing the Present Moment
10:40 - Why Space-Time Is Relative
14:00 - What is a Muon?
15:00 - Carl Anderson Discovers Muons
15:50 - Why Do the Muons Reach Us Before Decaying?
18:30 - Einstein's Notion of Time as Personal
20:30 - What Are Light Cones?
24:20 - Time Dilation and Length Contraction
27:00 - How Einstein Conceptualizes Space-Time
28:00 - Newtonian Rule for Time Travel
28:45 - Implications of Relativity