Image: Solar Dynamics Observatory spies rare encircling filament

They are usually elongated and uneven strands. Only a handful of times before have we seen one shaped like a circle. The black area to the left of the brighter active region is a coronal hole, a magnetically open region of the sun. While it may have no major scientific value, it is noteworthy because of its rarity. The still was taken in a wavelength of extreme ultraviolet light.