Dark Energy and the Runaway Universe

Alexei Filippenko, Univ. California-Berkeley

Abstract:

In 1998, observations of very distant exploding stars (supernovae) provided intriguing evidence that the expansion of the Universe is now speeding up, rather than slowing down due to gravity as expected. Today, new and completely independent observations strongly support this amazing conclusion. Over the largest scales of space, our Universe seems to be dominated by a repulsive "dark energy" of unknown origin, stretching the very fabric of space itself faster and faster with time. The physical nature of dark energy may provide an important clue to the long-sought theory unifying gravity and quantum physics.