Astronomers See Decoupling of Dark and Normal Matter in Collision of Two Galaxy Clusters

[Grim Reaper 6]

The two galaxy clusters, known collectivity as MACS J0018.5+1626, each contain thousands of galaxies and are located billions of light-years away from Earth. As they plowed through each other, the dark matter sped ahead of the normal matter.?

Think of a massive collision between multiple dump trucks carrying sand. The dark matter is like the sand and flies ahead,” said Emily Silich, an astronomer at Caltech and Harvard & Smithsonian’s Center for Astrophysics.

Such decoupling of dark and normal matter has been seen before, most famously in the Bullet Cluster.

In that collision, the hot gas can be seen clearly lagging behind the dark matter after the two galaxy clusters shot through each other.

The situation that took place in MACS J0018.5+1626 is similar, but the orientation of the merger is rotated, roughly 90 degrees relative to that of the Bullet Cluster..

https://www.sci.news/astronomy/dark-normal-matter-decoupling-13144.html