An intense series of eruptions on the sun may trigger a strong geomagnetic storm on Earth Thursday (Aug. 18), spawning stunning aurora displays farther south of their usual polar regions.
The geomagnetic storm, a G3 category according to the U.S. National Oceanic and Atmospheric Administration (NOAA), will result from interactions between the strong solar wind blowing from a "hole" in the upper atmosphere of the sun, called the corona, and the Earth's magnetic field. The storm will get additional fuel from two coronal mass ejections (CMEs) that erupted from the sun earlier this week and are currently on their way to the planet.
Space weather forecasters are still waiting for the two CME's to reach NOAA's Deep Space Climate Observatory (DSCOVR) satellite, about 1 million miles (1.5 million kilometers) away from Earth toward the sun, to get an exact idea of the strength and direction of the magnetic field carried by those CMEs, NOAA said in a statement.
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CMEs are bursts of magnetized plasma from the sun that escape from sunspots when the tense magnetic lines in these regions temporarily break. In the past week, space weather experts have seen multiple CMEs erupting from the sun, but most of them were not Earth-directed.
There are currently 10 active sunspots on the visible part of the sun, according to the U.K. weather forecaster Met Office, generating solar flares and CMEs. The two CMEs that are currently heading to Earth both burst from a "complex" sunspot, called region 3078 by NOAA. This region, located in the sun's southwest, is currently the largest and most active region on the visible disk of the sun and consists of "strong," magnetically complex spots, the Met Office said in the statement.
Solar flares are flashes of electromagnetic radiation that travel at the speed of light and can disrupt radio-communications on Earth. Unlike the CMEs, which take up to three days to arrive, there is no advance warning before the onset of the effects of solar flares.
The space weather forecasters are also observing two coronal holes, from which solar wind escapes at high speeds. Coronal holes are regions in the corona where the sun's magnetic lines are disrupted, creating an opening from which solar wind can easily escape.
Despite all this activity on the sun, NOAA expects no major impacts on our technological world, as a G3 storm is still relatively weak. More potent storms, category G4 and G5, can cause power blackouts, disrupt satellite communication links and even destroy satellites in orbit.
In February this year, SpaceX lost a batch of 40 Starlink satellites after it launched into a relatively mild geomagnetic storm. Other operators of low Earth orbit satellites reported problems due to the sun's activity in recent months as the interaction of the solar wind with the upper atmosphere increases drag on the satellites, which then fall back to Earth faster.
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