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.

2022 September 13
The featured image shows a long filament snaking across the
face of the Sun. 
Please see the explanation for more detailed information.

A Long Snaking Filament on the Sun
Image Credit & Copyright: Alan Friedman (Averted Imagination)

Explanation: Earlier this month, the Sun exhibited one of the longer filaments on record. Visible as the bright curving streak around the image center, the snaking filament's full extent was estimated to be about half of the Sun's radius -- 350,000 kilometers long. A filament is composed of hot gas held aloft by the Sun's magnetic field, so that viewed from the side it would appear as a raised prominence. A different, smaller prominence is simultaneously visible at the Sun's edge. The featured image is in false-color and color-inverted to highlight not only the filament but the Sun's carpet chromosphere. The bright dot on the upper right is actually a dark sunspot about the size of the Earth. Solar filaments typically last from hours to days, eventually collapsing to return hot plasma back to the Sun. Sometimes, though, they explode and expel particles into the Solar System, some of which trigger auroras on Earth. The pictured filament appeared in early September and continued to hold steady for about a week.

Tomorrow's picture: waving space lizard


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