X-Rays from 100 Million Degree Gas (IMAGE) University of Waterloo Caption An X-ray image reveals the hot plasma that envelopes the Perseus cluster. Located some 240 million light years from earth, the Perseus cluster is one of the largest known structures in the universe. The cluster includes not only the ordinary matter that makes up the galaxies, but an "atmosphere" of hot plasma with a temperature of tens of millions of degrees, as well as a halo of invisible dark matter. Data from the Hitomi satellite reveals that although the black hole at the heart of the Perseus cluster has only one-thousandth of the mass of its host galaxy, and has a much smaller volume, it seems to have a huge influence on how the galaxy and how the surrounding hot plasma atmosphere evolve. Credit University of Waterloo Usage Restrictions None License Licensed content Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.