Ask A Physicist: Why Believe In Dark Matter? 11Dr. Dave Goldberg and 97 others eEditaDeleteBPromoteXDismissXUndismissbBlock for sitebHide On today's episode of our "Ask A Physicist" series, Dr. Goldberg tackles the darker side of the universe - Dark Matter, that is. What is this curious cosmic stuff, and why should we care? » 5/01/10 9:00am 5/01/10 9:00amAsk A Physicist Any Question You Want About The UniverseIf The Universe Is Expanding, What's It Expanding Into?