Physics Nobel Explainer: Why Is Expanding Universe Accelerating?
More than a decade after prize-worthy find, dark energy still baffles.
What goes up must come down. Few on Earth would argue with the fundamental law of gravity. But today the 2011 Nobel Prize in Physics was awarded to three scientists who uncovered a dark side of the force.
New Nobel laureates Saul Perlmutter and Adam Riess of the U.S. and Brian Schmidt of Australia contributed to the discovery that the universe is not only expanding but also speeding up.
The finding led to the now widely accepted theory of dark energy, a mysterious force that repels gravity. Measurements show that dark energy accounts for about 74 percent of the substance of the universe.