This artist's animation shows a typical young galaxy, teeming with hot, newborn stars and exploding supernovas. The supernovas are seen as white flashes of light.
NASA's Galaxy Evolution Explorer spotted three-dozen young galaxies like the one shown here in our corner of the universe. It was able to see them with the help of its highly sensitive ultraviolet detectors. Because newborn stars radiate ultraviolet light, young galaxies light up brilliantly when viewed in ultraviolet wavelengths. The findings came as a surprise, because astronomers had thought that the universe's "birth-rate" had declined, and that massive galaxies were no longer forming.