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Basking in the Heat of the Universe

WASHINGTON, D.C.--Scientists have found new evidence for a cosmic infrared background radiation, a sort of fossil radiation thought to have been emitted during the earliest surge of star and galaxy formation. This warm glow puts a limit on the total amount of energy released by all the stars in the universe, which will help improve development of models explaining the birth and evolution of stars and galaxies after the big bang.

Unlike the cosmic microwave background, the infrared (IR) radiation was given off after formation of stars and galaxies had begun, perhaps from galaxies shrouded in dust. The new results were obtained by two groups of astronomers who drew data from an experiment aboard NASA's Cosmic Background Explorer satellite. One team, led by Michael Hauser of the Space Telescope Science Institute in Baltimore, announced its findings here today at a meeting of the American Astronomical Society.

A second group also detected the IR signature in the satellite data. When researchers meticulously subtracted emissions from bright, patchy sources in the Milky Way, background radiation emerged. It "just popped out of the analysis," says Marc Davis of the University of California, Berkeley, who, with David Schlegel of the University of Durham in the U.K. and Berkeley's Doug Finkbeiner, has submitted their calculations to The Astrophysical Journal.