In 2003, new evidence cemented the bizarre idea that the universe is made mostly of mysterious "dark matter," being stretched apart by an unknown force called "dark energy." This set of discoveries claims top honors as the Breakthrough of the Year, named by Science and its publisher, AAAS, the nonprofit science society.

These insights into our "dark" universe plus nine other research advances make up Science's top ten scientific developments in 2003, chosen for their profound implications for society and the advancement of science. The Top Ten list appears in the journal's 19 December issue.

This year, information from the Wilkinson Microwave Anisotropy Probe (WMAP) satellite and the Sloan Digital Sky Survey (SDSS) telescopes confirmed some of cosmologists' strangest proposals about the fate of the universe.

"The implications of these discoveries about the universe are truly stunning. Cosmologists have been trying for years to confirm the hypothesis of a dark universe. Science is glad to recognize their success in this effort as the Breakthrough of the Year for 2003," said Don Kennedy, Editor-in-Chief of Science.

Those proposals entered the spotlight five years earlier, when Science's 1998 Breakthrough of the Year honored the discovery that the universe was expanding. Such an expansion would likely be driven by a "dark energy" that counters the effects of gravity. At the time, however, many cosmologists were wary of this strange idea.

Their doubts were dispelled in 2003. WMAP took the most detailed picture ever of the cosmic microwave background -- the light emitted by the universe during the first instant of its existence. B
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Contact: Christina Smith
ccsmith@aaas.org
202-326-7088
American Association for the Advancement of Science
18-Dec-2003