What you should know about the massive sunspot facing Earth again

Culprit? A geomagnetic storm caused by high-energy particles and magnetism emanating from a sunspot—a bluish color on the surface of the Sun. The same sunspot cluster that spent several weeks hiding on the backside of the Sun is now spinning back toward Earth again.

There is a chance that additional geomagnetic storms of varying strength could occur over the next two weeks or so as the sunspot crosses the solar disk from left to right. (The Sun takes about 27 days to rotate once.) Another extreme geomagnetic storm is unlikely in the near future, but moderate to strong geomagnetic storms are not out of the question if a solar flare is ejected from a favorably placed sunspot. cluster.

This is technically the third time this sunspot cluster has encountered Earth. He was on his way to us in the first half of May and then came back at the end of the month until the beginning of June. Now Earth is once again in the line of fire.

Each time a sunspot cluster returns to the side of the Sun facing Earth, it is assigned a new number. In May it was “Active Area 3664”. Then the 3697. Now it’s the AR3723 — and it’s bursting with magnetism.

On Sunday, for example, AR3723 spat out an M-class solar flare. That’s the second-highest level on the scale (it’s A, B, C, M, and X, with X-class flares being the largest). The pulse of radiation helped ionize Earth’s upper atmosphere and created a reported shortwave radio blackout over the Atlantic for several hours. And the AR3723 is poised to spit out more magnetic hiccups in the coming days and weeks.

Solar flares are intense explosions of high-energy particles and electrons that hurtle through space at nearly the speed of light. They appear as intense flashes of light flashing in the sun. They are sometimes followed by slower-moving shock waves of magnetism, known as coronal mass ejections (CMEs); hurtling through space like an interstellar tsunami. If a CME hits Earth, its chaotic magnetism can interact with Earth’s magnetic field to produce episodes of northern (and southern) lights.

It’s too early to know exactly what AR3723 has in store.

It will take another day or so to rotate into a better view on observation satellites, which will help scientists at the Space Weather Prediction Center in Boulder, Colorado, better determine its magnetic structure. From there, scientists can make probabilistic predictions—projecting, for example, the likelihood of an M- or X-class solar flare in a given time frame. These eruptions send high-energy particles toward Earth, which can lead to shortwave radio blackouts on the sunlit side of the planet.

The Sunspot Cluster is much smaller than it once was. But its magnetic structure is evidently still sufficient to spit out powerful eruptions. The Center for Space Weather Prediction noted that AR3723 “remained the most magnetically complex group of spots” but had not evolved much over the past day.