This image shows three different galaxies taken in visible light (bottom
three images) and ultraviolet light (top row) taken by NASA's Ultraviolet
Imaging Telescope (UIT) on the Astro-2 mission. Pictures of galaxies like
these show mainly clouds of gas containing newly formed stars many times
more massive than the sun, which glow strongly in ultraviolet light. In
contrast, visible light pictures of galaxies tend to be dominated by the
yellow and red light of older stars.