Abell 2218: A Galaxy Cluster Lens
Credit:
W. Couch (University of New South Wales),
R. Ellis (Cambridge University),
NASA
Gravity can bend light.
Almost all of the bright objects in
this Hubble Space Telescope image are galaxies in the cluster
known as Abell 2218.
The cluster is so massive and so compact that its
gravity bends and focuses the light
from galaxies that lie behind it.
As a result,
multiple images of these background galaxies
are distorted into faint stretched out arcs -
a simple lensing effect analogous to viewing distant street lamps through
a glass of wine.
The Abell 2218 cluster itself is about 3 billion light-years away
in the northern constellation Draco.