Virgo Cluster

The Bullet Cluster is a pair of colliding galaxy clusters whose components have been torn apart by impact. Its galaxies and most of its mass passed through relatively cleanly, while the hot ordinary gas lagged behind, making the system one of astronomy’s clearest pieces of evidence that most matter in galaxy clusters is dark matter.

Object class

Colliding galaxy clusters

Composition

~40 galaxies, hot intracluster gas, dark matter

The Virgo Supercluster is the larger galactic neighborhood that contains the Virgo Cluster, the Local Group, and many other nearby galaxy groups and clusters. It was long used as the standard name for our home supercluster-scale environment before larger flow-based structures such as Laniakea became common in cosmography.

Object class

Galaxy supercluster

Composition

At least 100 galaxy groups and clusters, galaxies, hot intergalactic gas, dark matter

NGC 6872 is one of the largest known spiral galaxies and is caught in a strong gravitational interaction with its smaller companion IC 4970. The encounter has stretched its spiral arms into enormous tidal extensions, giving the system a tip-to-tip span of more than 700,000 light-years.

Object class

Interacting giant spiral galaxy

Host

Pavo group

Composition

Hundreds of billions of stars, gas, dust, dark matter