Two galaxy clusters that previously collided are now heading for another round of cosmic headbutt, NASA's Chandra X-ray Observatory and other telescopes have found. Located 2.8 billion light years from Earth, each of the two galaxy clusters contain thousands of galaxies, vast quantities of dark matter and superheated gas.
The two colliding clusters, together known as PSZ2 G181, resemble an irregular violet peanut shell with bulbous ends linked by a tapered middle. A composite image of the cosmic event shows crescent-shaped structures surrounding the system.
As per the astronomers, these are likely shock fronts, described as massive, sonic-boom disturbances, often located near a dense core remnant. The shock fronts created from the initial impact have since moved apart and are now about 11 million light-years away from each other - the widest separation ever recorded. This suggests just how massive and long-lasting the effects of galaxy collisions can be.
"Bracketing the combined galaxy cluster, these shock fronts were caused by the initial collision about a billion years ago. They are currently separated by 11 million light-years," NASA stated.
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Despite their enormous distance, the galaxy clusters are gravitationally bound and slowly turning back for another high-speed impact.
"Now, data from NASA's Chandra and ESA's XMM-Newton is providing evidence that PSZ2 G181 is poised for another collision. Having a first pass at ramming each other, the two clusters have slowed down and begun heading back toward a second crash."
As per Andra Stroe, the lead author of the study, the second encounter offers scientists the chance to observe a lower-mass system undergoing the kind of large-scale violence typically seen in more massive clusters.
Additionally, the collision could provide more insights into the mysterious unseen substance known as dark matter, as well as the evolution of the universe.
