Astronomers witness the birth of a very distant cluster of galaxies from the early universe

Using the Atacama Large Millimeter/submillimeter Array (ALMA), of which ESO is a partner, astronomers have discovered a large reservoir of hot gas in the still-forming galaxy cluster around the Spiderweb galaxy--the most distant detection of such hot gas yet. Galaxy clusters are some of the largest objects known in the universe and this result, published today in Nature, further reveals just how early these structures begin to form.