by A jumbled region of sunspots pointing almost directly at Earth has just emitted a large solar flare, which could wreak havoc on power and communication networks for days to come.
NASA Solar Dynamic Observatory (SDO) first detected the sunspot area designated AR3006 (“AR” stands for “active region”) several days ago; now the region is located near the center of the sun’s visible disk.
The SDO images show that a point near the center of the region has the reverse magnetic polarity of the surrounding area, meaning its magnetic field lines point in the opposite direction to nearby field lines. This mismatch creates an unusual situation that can cause large disturbances, called “magnetic reconnections“when areas of different polarity interact.
And now it seems that the interaction has occurred. Satellites in Earth orbit have detected a radio burst indicating a class X1.5 flare it erupted from AR3006 shortly before 9 am ET (1400 Universal Time) on Tuesday (May 10). Experts told WordsSideKick.com that the resulting flash is impressive, though not necessarily that unusual.
The flare is also likely to have caused a coronal mass ejection (CME), releasing a droplet of plasma that could impact land in the next few days.
Related: Strange new type of solar wave defies physics
There are five classes of solar flares: A, B, C, M, and X. according to nasa. Each is 10 times more powerful than the previous class and is followed by a number from 1 to 9 indicating their strength within that class.
But there is theoretically no limit to the strength of the largest X-class flares: the most powerful on record, from 2003, outperformed sensors by a rating of X28.
coronal mass ejection
Jan Janssens, a communications specialist at the Solar-Terrestrial Center of Excellence in Brussels, which coordinates international efforts to monitor the sun, called the new solar flare “impressive.”
But “I’m a little surprised at the strength of the flare, because this was all just about small sunspots,” Janssens told LiveScience in an email.
AR3006 is a relatively small patch of sunspots developing on the remnants of a decaying active region, but its structure of mixed polarities means it has a higher chance of breaking up and releasing droplets of energy into space, he said.
Solar physicist Dean Pesnell of NASA’s Goddard Space Flight Center, the Solar Dynamics Observatory project scientist, said the mixed polarity of the AR 3006 region was not uncommon.
“It happens when twisted magnetic field lines spin below the surface before exploding,” Pesnell told Live Science in an email, adding that solar flares also seemed more common in regions with such complicated magnetic fields.
Tuesday’s solar flare also caused an outburst of radio waves indicating that it was accompanied by a coronal mass ejection (CME) of superhot plasma from the sun.
CMEs typically emit billions of tons of stellar material at speeds of hundreds of miles per second, according to the NOAA Space Weather Prediction Center.
If CME material from the latest flare impacts Earth in the next few days, it has the potential to disrupt power grids and communications networks, and damage satellites.
Right now, the sunspot region is pointed almost directly at us, Janssens noted, but any risk of CME disruption will diminish in the coming days as AR3006 turns toward the western edge of the sun’s visible disk.
Pesnell explained that determining whether a CME would hit Earth was a “difficult and interesting calculation” that depends on the location and dynamics of the CME filament. While such events were “clues to how the solar dynamo works,” Pesnell said, “we only see the results of the dynamo, rather than the actual mechanism.”
“It’s like trying to understand the water cycle on Earth by looking only at the tops of clouds and not knowing about precipitation and the oceans below,” he said.
magnetic fields
Sunspots are caused by magnetic disturbances in the sun’s outer layer that expose the slightly cooler layer below. Even average sunspots are larger than Earth, and the largest sunspots can be many times larger.
Although sunspots and solar flares occur most frequently near the peaks of the 11-year solar activity cycle, they are actually the result of a longer 22-year cycle in the polarity of the sun’s magnetic fields.
The sun’s magnetic fields become entangled as it rotates through space about once every 27 days, according to nasa. At the peak of a solar cycle, roughly every 11 years, the sun’s fields become so entangled that the entire star abruptly reverses its magnetic polarity, the equivalent of Earth swapping its magnetic poles.
When that happens, sunspot activity decreases as the entangled magnetic fields unravel again, until the sun has almost no sunspots at the low point of the solar activity cycle.
But the cycle begins again when the sun’s magnetic fields begin to become entangled again; and so it takes 22 years until the sun’s magnetic polarity is the same as before.
Although it may seem that the sun has been very active in recent months, Live Science previously reported that its activity is about the same as during the last solar cycle, and even lower than at this time in the previous two cycles.
Records of the solar activity cycle began in 1775, and we are currently in the ascending phase of Solar Cycle 25; it is expected to peak in late 2024 or early 2025.
Originally published on Live Science.
