Astronomy Picture of the Day

Discover the cosmos! Each day a different image or photograph of our fascinating universe is featured, along with a brief explanation written by a professional astronomer.

July 10, 1995

Abell 2218: A Galaxy Cluster Lens
Picture Credit: NASA, HST, WFPC2, W. Couch (UNSW)

Explanation: Sometimes one of the largest concentrations of mass known can act like a lens. Almost all of the bright objects in this image are galaxies in the cluster known as Abell 2218. The cluster is so massive and so compact that it bends light from galaxies that lie behind it, causing many of them to appear as stretched out arcs. Many dim, elongated arcs are visible on this photograph. This picture was taken with the Wide Field Planetary Camera 2 on board the Hubble Space Telescope.

For more information about this picture see the Space Telescope Scientific Institute's press release.

Tomorrow's picture: Microlensing of the Einstein Cross

Authors & editors: Robert Nemiroff (MTU) & Jerry Bonnell (USRA)
NASA Technical Rep.: Jay Norris. Specific rights apply.
A service of: LHEA at NASA/ GSFC
&: Michigan Tech. U.