The James Webb Space Telescope (JWST) has made a fresh discovery, spotting the most distant galaxy cluster ever found — which is almost 30 billion light-years away. The cluster consists of 7 galaxies (that had previously been observed with the Hubble Space Telescope), but their distance and whether they were truly bound together was still unknown. Using JWST’s spectrometer, the scientists measured the redshifts of these galaxies, which are caused by the expansion of the universe, revealing that all 7 were aligned at the exact same redshift.
Since light takes time to travel from distant objects to JWST’s position orbiting the sun, the telescope sees these galaxies as they were about 650 million years after the big bang. The proto-cluster may seem small from our current perspective, but if its light could reach us instantly, it would be colossal, having gravitationally roped in thousands of other galaxies. Researchers’ simulations suggest that this proto-cluster may now be one of the most enormous clusters in the universe.
Takahiro Morishita, a researcher at the California Institute of Technology, explained that astronomers knew about the over-density of galaxies for some time, but it was still surprising when all seven galaxies were observed at the exact same redshift. Benedetta Vulcani at the National Institute of Astrophysics in Italy compared the distant galaxies to small drops of water in different rivers, saying that eventually, they would all become part of one big, mighty river. This discovery is essential in our understanding of the universe’s evolution, and it opens doors for further exploration and discoveries.