This week, the Sun featured a very long filament that stretched at least half way across the Sun (Oct. 20-22, 2015).
These long snake-like filaments are elongated clouds of plasma that are tethered above the Sun by magnetic forces.
They are often unstable and usually break apart in less than a week, though they can last longer than that. Filaments are darker than most of the Sun's surface when viewed in extreme ultraviolet light because they are not as hot as the sun's surface behind them.
The birth and death of filaments is a mystery and the subject of ongoing study by solar scientists.
Watch the video here.
Also read: http://sdo.gsfc.nasa.gov/gallery/potw/item/671?linkId=18229418
Credit: Solar Dynamics Observatory, NASA.
