Astronomers Rule Out Starburst Galaxies as Contributing to the Far-Ultraviolet Background

Astronomers using the Hopkins Ultraviolet Telescope (HUT), flown aboard the Shuttle ASTRO-2 mission, have been able to exclude one explanation for the mysterious far ultraviolet background radiation that existed when the universe was young. They find that starburst galaxies -- galaxies forming new stars at an extremely high rate -- were largely opaque to the UV radiation from hot newborn stars embedded within them. Contrary to earlier ideas, this means that starburst galaxies did not contribute significantly to heating, or ionizing, the early universe.