Cosmic Background Explorer (COBE)

U.S. satellite that from 1989 to 1993 mapped the cosmic background radiation field. In 1964, microwave radiation was discovered that permeated the cosmos uniformly. This radiation provided spectacular support for the big bang theory, which held that the early universe was very hot. In order to test theories of the universe's history, cosmologists needed to know whether the field was truly the same in every direction. COBE's all-sky survey of the radiation showed slight “wrinkles” from density variations. These variations would have stimulated galaxy formation. A spectrometer showed that the background radiation's spectrum precisely matched the theory.

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