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.
July 13, 1997
Explanation: About 11,000 years ago a star in the constellation of Vela exploded. This bright supernova may have been visible to the first human farmers. Today the Vela supernova remnant marks the position of a relatively close and recent explosion in our Galaxy. A roughly spherical, expanding shock wave is visible in X-rays. In the above optical photograph, the upper left corner of the spherical blast wave is shown in detail. As gas flies away from the detonated star, it reacts with the interstellar medium, knocking away closely held electrons from even heavy elements. When the electrons recombine with these atoms, light in many different colours and energy bands is produced.
Authors & editors:
NASA Technical Rep.: Jay Norris. Specific rights apply.
A service of: LHEA at NASA/ GSFC
&: Michigan Tech. U.