Astronomy Picture of the Day

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

July 18, 1995
See Explanation. Clicking on the picture will download the highest resolution version available.
Cygnus Loop Supernova Shockwave
Credit: NASA, HST, WFPC2, Jeff Hester

Explanation: 15,000 years ago a star in the constellation of Cygnus exploded. This picture shows a portion of a shockwave from this supernova explosion still expanding past nearby stars. The collision of this gaseous shockwave with a stationary gas cloud has heated the gas causing it to glow in a spectacular array of colors, known as the Cygnus Loop. This picture was taken with the Wide Field and Planetary Camera 2 on board the Hubble Space Telescope.

For more information see the NASA Hubble Space Telescope press release.

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Astronomy Picture of the Day is brought to you by Robert Nemiroff and Jerry Bonnell . Original material on this page is copyrighted to Robert J. Nemiroff and Jerry T. Bonnell.