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.
December 31, 1997
Explanation: Some stellar nebulae are strangely symmetric. For example, every major blob of gas visible on the upper left of NGC 5307 appears to have a counterpart on the lower right. This picture taken by the Hubble Space Telescope was released last week. NGC 5307 is an example of a planetary nebula with a spiral shape. Spiral planetary nebulae are thought to be caused by a bright central white dwarf star expelling a symmetric wobbling jet of rapidly moving gas. It takes light about 10,000 years to reach us from NGC 5307, and about 6 months just to go from one side to the other. In contrast, light takes only about 8 minutes to reach Earth from the Sun.
Authors & editors:
NASA Technical Rep.: Jay Norris. Specific rights apply.
A service of: LHEA at NASA/ GSFC
&: Michigan Tech. U.