X-ray Astronomy
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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