This was
your sky.

Cluster Crash Illuminates Dark Matter Conundrum

In Abell 520, huge galaxy clusters are colliding, creating a puzzle for astrophysicists. The dark matter, shown in blue, is separating from the normal matter, seen in red from Chandra X-ray Observatory data. This separation is unexpected and challenges our understanding of dark matter. The individual galaxies are visible, but the invisible components are the real mystery.