The culprit? A geomagnetic storm caused by energetic particles and magnetism emanating from sunspots, the scar-like discolorations on the sun’s surface. These same sunspots that have been hiding on the far side of the sun for weeks are now beginning to rotate toward Earth again.
Over the next couple of weeks, more geomagnetic storms of various strengths are possible as sunspots move from left to right across the solar disk. (The Sun takes about 27 days to complete one revolution.) While it is unlikely that we will see another extreme geomagnetic storm in the near future, a solar outburst from a favorably positioned sunspot group could result in a moderate to severe geomagnetic storm.
This is technically the third time that these sunspots have faced Earth: They were headed toward Earth in early May, then again at the end of the month and into early June, and now Earth is once again in the crossfire.
Each time a sunspot group returns to the side of the sun facing Earth, it’s assigned a new number: in May it was Active Region 3664. Next was 3697. And now it’s AR3723, a magnetic, crackling mess.
For example, on Sunday, AR3723 erupted an M-class solar flare, the second highest level on the scale (A, B, C, M, X being the largest). This pulse of radiation ionized Earth’s upper atmosphere,Shortwave radio outage reported AR3723 is expected to spit out more magnetic anomalies over the coming days and weeks.
Solar flares are violent explosions of high-energy particles and electrons hurtling through space at close to the speed of light. They appear as bursts of intense light that flicker across the Sun. They are sometimes followed by slow-moving magnetic shock waves called coronal mass ejections (CMEs), which hurtle through space like interstellar tsunamis. When a CME strikes Earth, its chaotic magnetic fields interact with Earth’s magnetic field, creating the aurora borealis (and the southern lights).
It’s too early to know exactly what the AR3723 has in store.
While the satellites’ view is still about a day away, scientists at the Space Weather Prediction Center in Boulder, Colorado, will be able to get a better picture of the sun’s magnetic structure. From there, they can make probability predictions, such as the likelihood of an M- or X-class solar flare occurring within a given time period. These flares shoot high-energy particles toward Earth and can cause a blackout of shortwave radio signals on the side of the sun that is closest to Earth.
The sunspot group is much smaller than it used to be, but its magnetic structure is apparently still strong enough to erupt powerful flares. The Space Weather Prediction Center noted that AR3723 “remains the most magnetically complex sunspot group,” but that it hasn’t changed much over the past day or so.
“It’s back,” says sunspot group AR3664, which produced a spectacular auroral event on May 10-11. It’s smaller in size but still impressive. Centered around 1303 UTC / 6:03 AM PDT, it emitted a near X-class flare that temporarily degraded HF communications.Tamissa Skov translator pic.twitter.com/cv4TTJtdhF
— Peter Vogel (@PeterVogel) June 23, 2024