Astronomers have discovered a galaxy cluster that appears to be a virtual island of calm and tranquility amid the violent and chaotic early universe.
The cluster, called SPT-CL J2215-3537 (SPT2215 for short), lies 8.4 billion light-years away and is thus seen as it was when the universe, now 13.8 billion years old, was just 5.3 billion years old. Conditions at that time were generally turbulent in the cosmos, and galactic clusters — conglomerations of up to hundreds of galaxies with gas, dust and dark matter woven between them — that existed then were subject to frequent collisions and mergers.
The history of those violent interactions can be traced by detecting X-rays emitted by hot gas in the clusters. Studying those X-rays has revealed to scientists that while collisions frequently disrupted these clusters, they also facilitated their growth. That means observing such galaxy aggregates that existed during early cosmic history is crucial in understanding how the universe has evolved.
Related: Hubble telescope captures the making of a 'cosmic monster' (photo)
