The Intergalactic Medium Family

  • Steven J. Dick
Part of the Astronomers' Universe book series (ASTRONOM)


We now move into the Family of the intergalactic medium, consisting of both gas and dust. Intergalactic gas is a hot, highly rarefied plasma consisting primarily of ionized hydrogen, along with traces of other elements such as helium and oxygen. It has been detected at temperatures ranging from 300,000 to five million degrees Celsius. This so-called Warm Hot Intergalactic Medium (WHIM) constitutes the bulk of the intergalactic medium (IGM). As with the interstellar medium, there is also a cooler neutral hydrogen component of the intergalactic medium in regions where there is not enough energy for ionization. Intergalactic molecules have not been discovered, but dust (G 16) also often coexists with the gas components.

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© Springer Nature Switzerland AG 2019

Authors and Affiliations

  • Steven J. Dick
    • 1
  1. 1.AshburnUSA

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