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 27, 1995

M57: The Ring Nebula
Credit: The Electronic Universe Project, Nelson Caldwell

Explanation: A star with mass similar to that of our Sun will throw off its outer gasses after fusion has stopped in its core. Possibly the most visually spectacular of these planetary nebula is the pictured Ring Nebula. The appearance as a ring is really an illusion of projection - the nebula is actually a spherical shell. At the center a blue dot is visible which is the old core of the star, known as a white dwarf. It is still not known exactly how the star throws off the gas that becomes the nebula.

For more information on the Ring Nebula see The Electronic Universe Project's write-up.

Many images of Messier objects can be found in The Electronic Universe Project's The Galaxy Gallery: Messier Objects.

Tomorrow's picture: M82: An Irregular Galaxy

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Astronomy Picture of the Day is created by Robert Nemiroff and Jerry Bonnell who are solely responsible for its content.