Faint blue galaxies. Hubble Space Telescope images of four irregular faint blue galaxies, the most common class of objects in the Universe. These galaxies are at a distance of between three billion and eight billion light years from Earth, and so are seen as they were at an early time in the life of the Universe. The blue areas denote intense star-forming activity. Many such galaxies have a wide range of shapes, unlike the spiral and elliptical galaxies common today. This suggests that the irregular galaxies have either faded or been destroyed by collisions and mergers over the last few billion years.