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APOD

Astronomy Picture of the Day

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.

See Explanation. Clicking on the picture will download the highest resolution version available.

Orange Sun Simmering

Explanation: Even a quiet Sun is a busy place. The above image , taken in a single color of light called Hydrogen Alpha , records a great amount of detail of the simmering surface of our parent star . The gradual darkening towards the Sun's edge, called limb darkening , is caused by increased absorption of relatively cool solar gas. Further over the edge, a giant prominence is visible, while a different prominence can be seen in silhouette as the dark streak near the image center. Two active areas of the Sun are marked by bright plages . The above amateur photograph of the Sun was taken just last month through a small telescope and a standard digital camera. In contrast, there are times when our Sun appears much more active .

Date July 29, 2003
Credit Credit & Copyright: Ralph Encarnacion
Authors & editors: Robert Nemiroff (MTU) & Jerry Bonnell (UMCP)
A service of: ASD at NASA / GSFC,
NASA Science Activation & Michigan Tech. U.