Scientists marvel as whirlpool forms ‘solar vortex’
NASA video shows plasma swirl around sun’s north pole
You’ve heard of the polar vortex, but how about a solar polar vortex?
Scientists and the public alike are in awe over a bizarre video that emerged of a vaporous-looking eddy of solar plasma swirling around the sun’s north pole. The footage was captured on Groundhog Day by NASA’s Solar Dynamics Observatory, a satellite launched in 2010. Since then, it’s gone viral on social media.
It shows a tendril-like filament of solar material erupting into space. From there, however, some of that material appears to be captured — and is slingshotted 360 degrees around the high latitudes of the sun’s northern hemisphere.
That raises the question — does the sun have a polar vortex? And if so, what is its purpose?
Bob Leamon is a solar heliophysicist and researcher at the University of Maryland-Baltimore and NASA Goddard. He said the “polar crown filament” was tracing a key magnetic boundary — one that can offer insight into forthcoming “space weather” and allow experts to better predict the frequency of impending solar storms.
“You can kind of think of the jet stream on Earth as what separates the polar regions of the atmosphere from the temperate zones and the tropics,” he explained. “The same thing is sort of true for the sun.”
That key boundary sits at 55 degrees latitude. (On Earth, that parallel would pass through Alaska, Quebec and Scotland — so imagine that on the sun.) There’s another similar interface in the sun’s Southern Hemisphere.
Here on Earth, our jet stream weaves the divide between air masses of different temperatures. On the sun, though, 55 degrees marks the boundary between zones of different magnetic structure.
“Fifty-five degrees latitude starts appearing in a whole bunch of diagnostics,” said Scott McIntosh, deputy director at the National Center for Atmospheric Research.
The sun is divided into horizontal (longitudinal) bands of magnetism. At any given point, there are usually four such bands that wrap around the sun. They alternate in polarity (north or south) and each hemisphere has two bands. That means 55 degrees is where the divider between bands starts. Over time, however, those bands diverge; one moves toward its respective pole, while the other shifts equatorward.
Scientists aren’t sure exactly what happens to one magnetic regime when it gets to a pole.
“Does the field get (absorbed) down into the sun’s core?” posited McIntosh. “We have no idea (where that magnetism goes).”
It takes roughly 11 years for a single band of magnetism to work from the 55 degrees (where the bands originate) to either the pole or the equator. That represents one solar cycle.
“I wouldn’t (set my clock to it),” said McIntosh. “It goes from 8 to 14 years.”
When a band reaches the equator, however, it encounters a strip of opposing magnetism arriving from the sun’s other hemisphere. That spurs something known as a terminator event, according to McIntosh.
The two opposite fields wage war in spectacular fashion, working to annihilate one another and brewing sunspots. Sunspots are bruiselike discolorations on the sun representing pockets of magnetic flux that hurl energy into space.
When that energy is Earth-directed, it can interact with our magnetic field, causing brilliant displays of the northern lights while disrupting GPS equipment and satellites.
At the poles, meanwhile, one band of magnetism disappears and is replaced by a new band of opposite polarity arriving from its origin near 55 degrees north or south latitude. That means the sun’s north and south poles flip polarity every 11 years on average.
So what’s the deal with our “solar vortex?” It’s a filament of solar plasma tracing neutral magnetic field lines between the northern hemisphere’s two bands of opposite polarity.
During a terminator event, the colliding midlatitude magnetic bands exhibit major magnetic interference around the equator. Sunspots are most numerous when interference is in high gear, which usually happens at the peak of a “solar cycle” following a terminator event. McIntosh proposed the last terminator occurred around the beginning of 2022, with an uptick in solar activity since.
“We’ve been observing a lot more activity around the polar crown the past few weeks,” said McIntosh. “That’s the thing that historically people have associated with solar maximum.”
The current solar cycle is expected by NASA and NOAA scientist to peak in July of 2025, though McIntosh and Leamon anticipate a peak in 2024 based on current observations.
“The first thing we see is the polar jet go up,” McIntosh said. That polar jet — or the invisible boundary that has been working north from its original perch near 55 degrees — is what corralled the now-viral “polar crown filament” from the video. “At polar reversal, 9 to 12 months from now, then we’ll see the bands that start solar cycle 26.”
Leamon and McIntosh note that there is still plenty to learn about the sun — particularly in the polar regions. Not only would scientists be able to better resolve magnetic disturbances at the poles, but they would be able to more holistically understand the process behind terminator events.
“This is a beautiful example of why we need to go up there and look,” McIntosh said.