Explanation:
Gravity can bend light, allowing huge clusters of galaxies
to act as telescopes.
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 long faint arcs -- a simple
lensing effect analogous to viewing distant street
lamps through a glass of
wine.
The
cluster of galaxies Abell 2218 is itself about three billion
light-years away in the northern constellation of the Dragon
(Draco).
The power of this massive cluster telescope has
allowed astronomers to detect a galaxy at
redshift 5.58, the
most distant galaxy
yet measured.
This young, still-maturing galaxy is
faintly visible to the lower right of the cluster core.
digg_url = 'http://apod.nasa.gov/apod/ap080210.html'; digg_skin = 'compact';
