Title:[3073] The distribution of 2 million galaxies on the sky Caption:The distribution of 2 million galaxies shown as a map made up of many tiny dots. Each dot represents a small patch of sky containing many images. Dots are black where there are no galaxies, white where there are more than 20 and gray for a number between 1 and 19. The overall mottled pattern is caused by small-scale clustering of the galaxies. The small bright patches are individual galaxy clusters. The larger elongated bright areas are super-clusters and filaments. These surround darker voids where there are fewer galaxies than average. Copyright: Credit:Dept. of Astrophysics, University of Oxford

Title:[3074] Galaxies of various ages, giving clues to how galaxies evolve (HST) Caption:These Hubble Space Telescope images of galaxies at various distances have been arranged to provide clues to the evolution of galaxies over time. Far left: nearby galaxies representing the current age of the universe (about 14 billion years); center left: galaxies in rich clusters when the universe was about two-thirds its present age - the ellipticals appear much as today but the spirals appear more disrupted; center right: the spirals have a less clear and more disrupted structure at one-third the present age of the universe, though the elliptical (top) is still clearly recognizable far right: in the universe one-tenth its current age, the distinction between spirals and ellipticals is less clear, though the top image looks very much like a mature elliptical galaxy, suggesting that ellipticals formed remarkably early. Copyright: Credit:A. Dressler, M. Dickinson, D. Macchetto, M. Giavalisco and NASA.

Title:[4061] Young Galaxy Building Blocks Caption: Embedded in this Hubble Space Telescope image of nearby and distant galaxies are 18 young galaxies or galactic building blocks, each containing dust, gas, and a few billion stars. Each of these objects is 11 billion light-years from Earth and much smaller than today's galaxies. The 18 young galaxies were found within an area about 2 million light-years across, which is about the distance between our Milky Way and the Andromeda galaxy. The image covers a diameter that is 13 times smaller than that of the full moon. At this distance, the universe was only about 16 percent of its current age. Copyright: Credit:R. Windhorst and S. Pascarelle (Arizona State University) and NASA

Title:[4063] Massive black holes in galaxies Caption:The three galaxies above are believed to contain central, supermassive black holes. The galaxy NGC 4486B (lower-left) shows a double nucleus (lower-right). The images of NGC 3377 and NGC 4486B are 2.7 arcseconds on a side, and for NGC 3379 the size is 5.4 arcseconds; the lower-right is a blow-up of the central 0.5 arcseconds of NGC 4486B. Copyright: Credit:K.Gebhardt (University of Michigan) and T.Lauer (NOAO)

Title:[4064] Gamma-ray burst fireball Caption:A Hubble Space Telescope image of the fading fireball from one of the universe's most mysterious phenomena, a gamma-ray burst. Though the visible component has faded to 1/500th its brightness (27.7 magnitude) from the time it was first discovered by ground-based telescopes. The continued visibility of the burst, and the rate of its fading, support theories that the light from a gamma-ray burst is an expanding relativistic (moving near the speed of light) fireball, possibly produced by the collision of two dense objects, such as an orbiting pair of neutron stars. The energy released in a burst, which can last from a fraction of a second to a few hundred seconds, is equal to all of the Sun's energy generated over its 10 billion year lifetime. Copyright: Credit:A.Fruchter (STScI), E.Pian (ITSRE-CNR), and NASA