Most of the gravity responsible for the bending is produced by unseen dark matter. (discovermagazine.com)
Gravity, primarily from unseen dark matter, can hold the ring in a nearly circular orbit around the host galaxy. (members.nova.org)
Galaxy cluster Abell 1689 seems to be held together by swaths of unseen dark matter; blue shows its theoretically inferred location. (discovermagazine.com)