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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.

Crepuscular Rays Over Utah

Explanation: What could cause such rays of dark? Dark sky rays were caught in spectacular fashion earlier this month above Kanab, Utah , USA . The cause is something surprisingly familiar: shadows . Clouds near the horizon can block sunlight from reflecting off air, making columns outward from the Sun appear unusually dark . Cloud shadow s can be thought of as the complement of the more commonly highlighted crepuscular rays , also visible above, where sunlight pours though cloud holes. Sometimes, on the opposite side of the sky, anticrepuscular rays can also be seen.

Date August 31, 2005
Credit Credit & Copyright: Jean Nesheim
Authors & editors: Robert Nemiroff (MTU) & Jerry Bonnell (UMCP)
A service of: ASD at NASA / GSFC,
NASA Science Activation & Michigan Tech. U.