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.

April 21, 1996

A Supernova in the Whirlpool
Credit: R. Kirshner (CfA), NASA

Explanation: In 1994, a new star in a distant galaxy was seen by amateur astronomers, who alerted the world to their discovery of a supernova. Near the nucleus of spiral galaxy M51, popularly known as the Whirlpool, this supernova (1994I) is identified as the bright spot indicated by the arrow in the lower left of this Hubble Space Telescope image. Supernovae are violent death explosions of stars that eject radioactive debri clouds. They are often discovered by amateur observers dedicated to systematic searches of the sky and are of intense interest to astronomers who hope to learn what kind of stars generate these explosions and what chemical elements are produced and mixed into space. Distances to these these intrinsically bright events can also be determined, providing crucial yardsticks for measuring the Scale of the Universe.

Tomorrow's picture: At the Edge of the Helix

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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.