“I’ve never seen anything like it before,” said NASA solar physicist Jack Ireland.
The event began at about 2:30 a.m. Eastern time and continued for several hours. The flare itself — the brief bright flash at the beginning of the video above — was fairly ordinary and medium-sized. But the loop of magnetized plasma ejected by the flare, called a filament, was at least as large as 10 Earths.
Filaments that large normally break free from the sun’s magnetic field and escape into space, said NASA solar physicist Alex Young. But this filament, perhaps because it didn’t have enough energy, simply broke up and fell back down. The splash covered almost half the sun’s diameter.
“The unusual part of this event is that a lot of material came back down and interacted with the surface of the sun in a really spectacular way,” Ireland said. “We don’t normally see it in such great detail.”
Rather than falling straight down, as it would if pulled only by gravity, the plasma rain followed invisible magnetic field lines. Some of the material was pulled into bright spots of magnetic activity called active regions.
“A lot of the material looked like it was going straight, but then curved into the active regions,” Young said. “The magnetic field from the active regions sucked the plasma into it. That’s not something I’ve seen before.”
The event was captured by NASA’s Earth-orbiting Solar Dynamics Observatory. But it first came to scientists’ attention after it was uploaded on a citizen science website called Helioviewer, which helps scientists and the public make YouTube videos from SDO data.
“The site has been a godsend for SDO data,” Young said. “As a scientist, I would not be able to look at SDO data in the way that I do now without Helioviewer.”
Because most of the charged material fell back onto the sun, Earth probably won’t experience any effects beyond extra shows of northern lights.
“It’s nothing to worry about,” Young said. “It’s just really, really beautiful.”