Google Talk: Dark Energy and the Runaway Universe (English)

We expected the attractive force of gravity to slow down the rate at which the Universe is expanding. But observations of very distant exploding stars (supernovae) show that the expansion rate is actually speeding up, a remarkable discovery that was honored with the 2011 Nobel Prize in Physics to the teams' leaders. Over the largest distances, the Universe seems to be dominated by a repulsive "dark energy" -- an idea Albert Einstein had suggested in 1917 but renounced in 1929 as his "biggest blunder." It stretches space itself faster and faster with time. But the physical origin and nature of dark energy, which makes up about 70% of the contents of the Universe, is probably the most important unsolved problem in all of physics; it may provide clues to a unified quantum theory of gravity.