Image of the Day: Galaxy Cluster Reveals Farthest Known Galaxy


Almost all of the bright objects in this Hubble Space Telescope image are galaxies in the cluster known as Abell 2218 -a cluster 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.

The cluster of galaxies Abell 2218 is itself about two billion light-years away in the northern constellation Draco. The power of this massive cluster telescope has recently allowed astronomers to detect a galaxy at a redshift of about 7, the most distant galaxy or quasar yet measured.

Three images of this young, still-maturing galaxy are faintly visible in the white contours near the image top and the lower right. The recorded light, further analyzed with a Keck Telescope, left this galaxy when the universe was only about five percent of its current age.

Credit: ESA, NASA, J.-P. Kneib (Caltech/Observatoire Midi-Pyrenees) & R. Ellis (Caltech)

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