IMAGES TAKEN BY CHANDRA OBSERVATORY AND HUBBLE SPACE, 2001-03-13 (photo)

"black holes, black holes and black holes." There may have been as many as 300 billion black holes in the entire sky when the universe was young, scientists said. Using the orbitting Chandra X-Ray Observatory (R), astronomers focused on the X-ray glow, a sort of blur in the background of images of galaxies, stars and other cosmic features. Astronomers have taken previous "core samples" using the Hubble Space Telescope (L), but that could only "see" things in visible light. Chandra takes pictures of objects using the X-rays they emit instead of the light they give off. JP