<\/p>\n Galaxy clusters are collections of dark matter<\/a> and hundreds to thousands of galaxies, all bound together by gravity. Those galaxies are separated by a mix of gas known as the intracluster medium. As galaxy clusters form, the intracluster medium heats up due to gravitational interactions within the cluster and energy emissions from young stars and black holes. But this process takes a long time, and scientists have only rarely observed a hot intracluster medium in young galaxy clusters.<\/p>\n You may like<\/p>\n “Understanding galaxy clusters is the key to understanding the biggest galaxies in the universe,” study co-author Scott Chapman<\/a>, an astrophysicist at Dalhousie University who conducted the research while at the National Research Council of Canada (NRC), said in a statement<\/a>. “These massive galaxies mostly reside in clusters, and their evolution is heavily shaped by the very strong environment of the clusters as they form, including the intracluster medium.”<\/p>\n In the new study, researchers used the Atacama Large Millimeter\/submillimeter Array (ALMA), a powerful radio telescope located in Chile, to observe a bright, young galaxy cluster known as SPT2349-56, whose light was emitted just 1.4 billion years after the Big Bang. This cluster is relatively small \u2014 about the size of the Milky Way<\/a>‘s outer halo \u2014 but it contains more than 30 active galaxies and three supermassive black holes, and it forms stars more than 5,000 times as fast as the Milky Way.<\/p>\n Using a phenomenon called the thermal Sunyaev-Zeldovich effect, the team found that the gas in the intracluster medium is at least five times hotter than current theories of cluster formation predict it should be for its relatively young age.<\/p>\n \n An artist\u2019s impression of the galaxy cluster SPT2349-56. (Image credit: ESO\/M. Kornmesser)<\/p>\n![\"Spinning,](\"https:\/\/www.europesays.com\/us\/wp-content\/uploads\/2026\/01\/iHVFMp8uVu76ZsVtzT5Mne.jpg\")
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