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.

2013 February 26

Coronal Rain on the Sun
Video Credit: Solar Dynamics Observatory, SVS, GSFC, NASA; Music: Thunderbolt by Lars Leonhard

Explanation: Does it rain on the Sun? Yes, although what falls is not water but extremely hot plasma. An example occurred in mid-July 2012 after an eruption on the Sun that produced both a Coronal Mass Ejection and a moderate solar flare. What was more unusual, however, was what happened next. Plasma in the nearby solar corona was imaged cooling and falling back, a phenomenon known as coronal rain. Because they are electrically charged, electrons, protons, and ions in the rain were gracefully channeled along existing magnetic loops near the Sun's surface, making the scene appear as a surreal three-dimensional sourceless waterfall. The resulting surprisingly-serene spectacle is shown in ultraviolet light and highlights matter glowing at a temperature of about 50,000 Kelvin. Each second in the above time lapse video takes about 6 minutes in real time, so that the entire coronal rain sequence lasted about 10 hours.

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