Under the watchful eyes of NASA's Solar Dynamics Observatory spacecraft, the sun is a raucous place of ever-changing features. It has dark snake-like filaments and gaping sunspots. Scientists were particularly interested when the SDO spotted a very strange sort of filament late last month. It's circular rather than stretched out like a strand.
NASA describes this phenomenon: "Solar filaments are clouds of charged particles that float above the sun, tethered to it by magnetic forces." The rounded filament encircles an active region of our nearest star and looks a lot like an unruly hair cowlick.
NASA says its researchers have only seen a handful of filaments like this one. "While it may have no major scientific value, it is noteworthy because of its rarity," the space agency says.
The unusual filament appeared in the SDO's view from Oct. 29 through 31. The large dark area to the left is a coronal hole, which appears almost black due to its cooler temperatures compared with its surroundings.
We've seen some spectacular filaments in the past, including atracked by the SDO in 2014. This circular filament is a fascinating counterpoint to that serpent-like formation.