An extremely hot, massive young galaxy cluster, the largest ever seen in the distant universe, has been studied by an international team using ESO’s Very Large Telescope (VLT) in the Atacama Desert in Chile along with NASA’s Chandra X-ray Observatory and the Atacama Cosmology Telescope. El Gordo which means the fat one in Spanish, is officially known as ACT-CL J0102-4915 and is located more than 7 billion light-years from Earth, at a time when the universe was half its current age. The monster galaxy cluster has mass about 2 quadrillion (that’s 2 followed by 15 zeroes) times that of the sun, making it the most massive known cluster in the distant universe.
Galaxy clusters form through mergers of smaller groups of galaxies. These events depend on the amount of dark matter and dark energy in the universe, and thus could shed light on these enigmas. Gas in El Gordo can reach super-high temperatures of nearly 360 million degrees Fahrenheit (200 million degrees Celsius), based on X-rays collected by Chandra and the European Southern Observatory’s Very Large Telescope in Chile. This heat, as well as the fact that galaxies within the cluster are concentrated in two distinct groups, suggests El Gordo is the site of a violent merger between two galaxy clusters. Although a cluster of El Gordo‘s size and distance is extremely rare, it does fit within the standard Big Bang model of cosmology. This suggests the universe is composed predominantly of dark matter and dark energy, and began with a Big Bang about 13.7 billion years ago.