Dr. Kaku explains how scientists recently slowed light to 20 miles per hour using Bose condensation, and why the universe appears to be accelerating toward a cold, dark future. The conversation turns to NASA's upcoming Deep Impact mission to slam a projectile into a comet and the controversial Cassini spacecraft carrying 72 pounds of plutonium set to fly just 700 miles from Earth in August 1999. Dr. Kaku reveals a classified memo estimating tens of thousands of potential casualties if Cassini were to reenter the atmosphere.
The discussion also covers rogue planets with possible subsurface oceans, genetic engineering ethics, the discovery of new super-heavy elements, and Einstein's brain autopsy revealing structural differences linked to abstract thinking. Callers press Dr. Kaku on M-theory's eleven dimensions and the clumpiness of the visible universe.
Key Moments
Theory of Everything as a one-inch equation: Kaku frames the unified field theory as a creation theory - an equation roughly an inch long defined in 10-dimensional hyperspace that would summarize all physical knowledge.
Multiverse as quantum beer foam: Kaku explains quantum foam - a vacuum filled with bubble universes constantly popping in and out of existence - and positions our 15-billion-year-old universe as one bubble among an infinite multiverse.
Time as a forking river, not a dammed arrow: Kaku resolves the grandfather paradox by describing time as a river that can fork into parallel timelines or form whirlpools - a time traveler who alters the past creates a second bubble universe rather than erasing their own.
One cosmic ray separates us from a Hitler-free timeline: Kaku speculates that a single quantum event - a cosmic ray through Hitler's mother's womb - could separate our universe from a parallel bubble where World War II never occurred, or where nuclear war wiped out humanity.
Cassini's 72 pounds of plutonium return on August 17: Kaku flags the Cassini Earth flyby coming in 33 days - a 13-ton probe carrying 72 pounds of plutonium swinging by at 700 miles altitude - and warns a classified memo says tens of thousands could die in a worst-case reentry.