What you need to know about the massive sunspot facing Earth again

The culprit? A geomagnetic storm, driven by high-energy particles and magnetism emanating from a sunspot—a bruise-like spot on the sun’s surface. The same group of sunspots that spent weeks hiding behind the sun is now hurtling back toward Earth.

There is a chance that more geomagnetic storms of varying strength could occur over the next two weeks or so as the sunspot moves from left to right across the solar disk. (It takes about 27 days for the sun to rotate once.) Another extreme geomagnetic storm is unlikely to occur in the near future, but moderate to severe geomagnetic storms are not out of the question if a solar flare erupts from the sunspot. favorably positioned. pile

It’s technically the third time this group of sunspots has faced Earth. He spent the first half of May aiming at us and then returned at the end of the month in early June. Now Earth is once again in the line of fire.

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

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

Solar flares are intense bursts of high-energy particles and electrons that race through space at nearly the speed of light. They appear as bright bursts of flickering light in the sun. Slower-moving shockwaves of magnetism, known as coronal mass ejections (CMEs), sometimes follow; they sweep through space like interstellar tsunamis. If a CME hits the Earth, its chaotic magnetism can interact with the Earth’s magnetic field, producing episodes of the northern (and southern) lights.

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

It will take another day to roll in a better view of the observing satellites, which will help scientists at the Space Weather Prediction Center in Boulder, Colo. to better define its magnetic structure. From there, scientists can make probabilistic predictions—projecting, for example, the chances of an M-class or X-class solar flare within a given time period. These flares send high-energy particles toward Earth, which can lead to shortwave radio outages on the planet’s sunward side.

The sunspot cluster is much smaller than it used to be. But its magnetic structure is, apparently, still sufficient to emit strong flames. The Space Weather Prediction Center noted that AR3723 “remained the most magnetically complex cluster of spots” but had not evolved much over the past day.