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The Einstein Cross

In this image of the Einstein Cross (Gravitational Lens G2237 + 0305), light from a distant quasar is seen to bend in its path by the gravitational field of the galaxy to produce four bright outer images. The diffuse central object is the bright core of the intervening galaxy. This image was obtained with the ESA Faint Object Camera (part of the Hubble Space Telescope).

The quasar is at a distance of approximately 8 billion light-years, while the galaxy is twenty times closer (400 million light years). Gravitational lensing occurs when the light from a distant source passes through or close to a massive foreground objec t. Depending on the detailed alignment of foreground and background objects with the line of sight to the Earth, several images of the background object may be seen.

Photo credit: NASA and European Space Agency (ESA)

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Copyright © 1995: Board of Trustees, University of Illinois

NCSA. Last modified 11/22/95.