Astronomers have discovered a galaxy cluster with an important characteristic; it's “relaxed, meaning that it shows no signs of having been disrupted by violent collisions with other clusters of galaxies. This composite image contains X-rays from Chandra (blue), which helped identify SPT2215 along with other telescopes, and data from Hubble (cyan and orange). Image Credit: X-ray: NASA/CXC/MIT/M. Calzadilla; UV/Optical/Near-IR/IR: NASA/STScI/HST; Image processing: N. Wolk
In the span of a human lifetime, much of the Universe seems unchanging. But that’s an illusion; things are always changing, and that fact can make galaxies and the clusters they reside in very unruly places due to mergers and collisions.
However, some galaxy clusters seem much calmer than others.
