In a result which has baffled astronomers at NASA’s Chandra X-ray Observatory, dark matter has been observed separating from galaxy clusters after a collision.
When galaxy clusters collide, astronomers expect the galaxies to be strongly bound to clouds of dark matter which act as gravitational ‘glue’. But in analysing the collision of galaxy clusters in the merging cluster Abell 520, a team of scientists found that the cluster’s core was rich in dark matter but contained no luminous galaxies. This seems to contradict earlier results.
Read more at University of California, Davis