This composite image from NASA's Chandra X-ray Observatory and Hubble Space Telescope (HST) combines the deepest X-ray, optical and infrared views of the sky. Using these images, astronomers have obtained the first direct evidence that black holes are common in the early Universe and shown that very young black holes grew more aggressively than previously thought.

A deep study of 29 gigantic blobs of hydrogen gas has been carried out with NASA's Chandra X-ray Observatory to identify the source of immense energy required to illuminate these structures. These mysterious blobs - called "Lyman-alpha blobs" by astronomers because of the light they emit - are several hundred thousand light years across and are seen when the Universe is only about two billion years old, or about 15% of its current age.

One of the most impressive accomplishments of the Chandra mission has been the improved understanding of the distant X-ray Universe. Chandra has accomplished this through deep X-ray surveys that generally involve pointing Chandra at a particular region of the sky that is not known to have any bright nearby objects and letting the camera collect X-ray light for an extended period of time.