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



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.