An overview of the Chandra mission and goals, Chandra's namesake, top 10 facts.
Classroom activities, printable materials, interactive games & more.
Overview of X-ray Astronomy and X-ray sources: black holes to galaxy clusters.
All Chandra images released to the public listed by date & by category
Current Chandra press releases, status reports, interviews & biographies.
A collection of multimedia, illustrations & animations, a glossary, FAQ & more.
A collection of illustrations, animations and video.
Chandra discoveries in an audio/video format.
Clues from Clusters of Galaxies

Chandra observations of the clouds of hot gas in clusters of galaxies contain clues to the origin, evolution and destiny of the universe:

  • Combined X-ray and microwave measurements can yield an estimate of the age of the universe.
  • Measurements of the numbers of clusters with extremely hot--greater than 100 million degrees--gas clouds will tell how galaxies formed from the expanding fireball of the Big Bang.
  • The pressure in the hot gas is an accurate probe of the amount of dark matter in clusters of galaxies. This knowledge obtained from X-ray measurements can be used to determine whether the universe will expand forever, or will ultimately collapse.
3C295 cluster - optical 3C295 cluster - X-ray

The optical image (left) of the 3C295 cluster shows hundreds of galaxies. The X-ray image shows a vast cloud of fifty million degree gas. The gas cloud, which is visible only with an X-ray telescope,

Return to: Galaxy Clusters | X-ray Discovery