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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.

See Explanation. Clicking on the picture will download the highest resolution version available.

A Quasar Portrait Gallery

Explanation: Quasars (QUASi-stellAR objects) lie near the edge of the observable Universe . Discovered in 1963, astronomers were astounded that such objects could be visible across billions of light-years, as this implies they must emit prodigious amounts of energy. Where does the energy come from? Many believe the quasar's central engine is a giant black hole fueled by tremendous amounts of infalling gas, dust, and stars. This gallery of quasar portraits from the Hubble Space Telescope offers a look at their local neighborhoods: the quasars themselves appear as the bright star-like objects with diffraction spikes . The images in the center and right hand columns reveal quasars associated with disrupted colliding and merging galaxies which should provide plenty of debris to feed a hungry black hole .

Date March 9, 2002
Credit Credit J. Bahcall ( IAS, Princeton ), M. Disney ( Univ. Wales ), NASA
Authors & editors: Robert Nemiroff (MTU) & Jerry Bonnell (UMCP)
A service of: ASD at NASA / GSFC,
NASA Science Activation & Michigan Tech. U.