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Adam Riess (born December 16, 1969, Washington, D.C., U.S.) is an American astronomer who was awarded the 2011 Nobel Prize for Physics for his discovery of dark energy, a repulsive force that is the dominant component (73 percent) of the universe. He shared the prize with physicist Saul Perlmutter and astronomer Brian Schmidt. Riess wrote articles on dark energy and dark matter for the EncyclopƦdia Britannica. Riess received a bachelor’s degree in physics from the...