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.

October 29, 1995
See Explanation. Clicking on the picture will download the highest resolution version available.
Radioactive Clouds in the Milky Way
Credit: NASA, Compton Gamma Ray Observatory, COMPTEL Collaboration,

Explanation: When massive stars explode they create large radioactive blast clouds which expand into interstellar space. As the radioactive elements decay, they produce gamma-rays. Possible locations of these stellar explosions known as supernovae, are indicated by the bright clumps in this map of the central regions of our Milky Way Galaxy. The map was made by a telescope onboard NASA's orbiting Compton Gamma Ray Observatory using detectors sensitive to gamma rays from the decay of radioactive aluminum.

Tomorrow's picture: Update on Comet Hale-Bopp

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Authors & editors: Robert Nemiroff (GMU) & Jerry Bonnell (USRA).
NASA Technical Rep.: Sherri Calvo. Specific rights apply.
A service of: LHEA at NASA/ GSFC