Geomagnetic Storm From 'Cyclops-Like' Hole in Sun to Hit Earth Today

A minor geomagnetic storm is predicted to occur at some point today as solar winds make their way to Earth from a "hole" in the sun's atmosphere.

Forecasters at the National Oceanic and Atmospheric Administration's Space Weather Prediction Center (SWPC) said on Monday that G1-strength geomagnetic storms "are likely on 6 July due to a geoeffective coronal hole high speed stream."

In other words, a gust of solar wind—a stream of charged particles—is due to interact with Earth's magnetic field, potentially causing minor disturbances for certain systems like satellites and power grids.

The solar wind is headed our way from what dubbed a "cyclops-like hole" on the sun, seen in the NASA Solar Dynamics Observatory image below.

Coronal hole
A NASA Solar Dynamics Observatory image of the sun on July 3 with a coronal hole seen in the center. The hole is thought to be responsible for solar winds causing a minor geomagnetic storm this week. NASA/SDO/AIA

Fortunately, the geomagnetic storm is nothing to worry about. As a G1 storm, it is the weakest type of geomagnetic storm on the SWPC's scale which goes up to G5. G1 storms happen fairly regularly, sometimes multiple times a month.

Still, a G1 storm can have some effects, including weak power grid fluctuations, a minor impact on satellite operations, and potentially auroras at lower latitudes than normal in states like Michigan and Maine due to changes in the Earth's magnetic field. There may also be changes to the behavior of migratory animals.

A G5 storm—a much rarer event—would be far more disruptive, potentially shutting down entire power grid systems and damaging transformers; problems with satellite data transfer; radio blackouts lasting for days; and auroras as low as Florida or Texas. A big enough geomagnetic storm in today's modern society could cost trillions of dollars in damage.

In any case, Wednesday's storm will likely not be noticeable to most people. The coronal hole in the sun's atmosphere from which the solar wind is originating is a documented phenomenon.

Coronal hole
A closer view of the coronal hole. The July 6 event is a G1 storm, the weakest type of geomagnetic storm on the SWPC's scale. NASA/SDO/AIA

The sun is continually releasing a steady stream of particles from its surface, and this stream is especially strong through these holes. Normally, magnetic field lines on the sun's surface keep these streams of particles relatively well contained.

However, sometimes these field lines don't close back on themselves, leaving an open channel through which the solar wind can blast at up to 500 miles per second, according to the Exploratorium museum in California.

Coronal holes appear dark in extreme ultraviolet and soft x-ray images because they are cooler, less dense regions than the surrounding plasma.

Other ways in which the sun can buffet Earth with particles and radiation is via solar flares and coronal mass ejections which can also cause disruption to Earth systems like communication networks and power grids.