Black Holes and Galactic Clusters

Black Holes and Galactic Clusters

Some astronomers believe that the gravity pulls of gigantic black holes may hold together vast galactic clusters such as the Virgo cluster consisting of about 2500 galaxies. Such clusters were formed after the Big Bang some 10 to 20 billion years ago. Why they did not spread randomly as the Universe expanded is not understood, as only a fraction of the mass needed to keep them together is observable.

NASA's Hubble Space Telescope and AXAF Telescope provide many more times the data than present ground and space observatories furnish and should contribute to resolving this and other mysteries of our Universe.