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.

2010 May 22
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Dark Filament of the Sun
Credit: NASA / Goddard / SDO AIA Team

Explanation: Suspended by magnetic fields above a solar active region this dark filament stretches over 40 earth-diameters. The ominous structure appears to be frozen in time near the Sun's edge, but solar filaments are unstable and often erupt. The detailed scene was captured on May 18 in extreme ultraviolet light by cameras on board the Solar Dynamics Observatory. While the cooler plasma of the filament looks dark, hotter, brighter plasma below traces magnetic field lines emerging from the active region. When seen arcing above the edge of the Sun, filaments actually look bright against the dark background of space and are called prominences.

Tomorrow's picture: fast sunspot

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Authors & editors: Robert Nemiroff (MTU) & Jerry Bonnell (UMCP)
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