After a series of eruptions on the Sun, the Earth can expect geomagnetic storms and auroral outbursts in the next few days.
A sunspot called AR2929 produced two solar flares accompanied by coronal mass ejections. Although neither was aimed at Earth, the emissions now rushing through space can deliver glancing blows to our planet’s atmosphere, which can cause geomagnetic storms.
The first flare occurred on January 18 at 5:44 p.m. UT and was classified as an M1.5 class flare. The second flare occurred on January 20 at 6:01 a.m. UT. It was more powerful and reached the M5.5 level. Both flares are considered medium flares – not the strongest our Sun can produce, but strong enough to be felt on Earth.
Both flares caused a burst of X-rays that ionized Earth’s upper atmosphere, resulting in short-lived, minor shortwave radio blackouts; the first flare occurred over South America and the second over the Indian Ocean.
Coronal mass ejections (CMEs), which result from the rupture and reconnection of magnetic field lines, are massive ejections of up to billions of tons of plasma from the solar corona, carrying an embedded magnetic field. They often occur in conjunction with solar flares and move outward from the Sun, taking several days to reach Earth if they are headed in our direction.
Otherwise, they can still strike lightning fast. This is exactly what we can observe in the case of the two CMEs from AR2929. The resulting geomagnetic storms will be minor: perhaps a few fluctuations in the power grid, a minor degradation of radio communications, and minor interruptions in space operations.
We may also see auroras when charged particles from the CME collide and interact with the Earth’s atmosphere and magnetic field, creating magnificent light shows at high latitudes.
Such flares become more frequent as the Sun approaches solar maximum, the peak of solar activity, which occurs during an 11-year cycle.
This cycle is based on the Sun’s magnetic field, which changes every 11 years, with the north and south magnetic poles swapping places. It is not known what causes these cycles (recent research suggests it has to do with the 11.07-year planetary alignment), but the poles change when the magnetic field is at its weakest, which is also known as the solar minimum.
The Sun’s magnetic field controls its activity, including sunspots (temporary areas of strong magnetic field), solar flares, and coronal mass ejections, so the solar minimum appears as a period of minimum activity. After the pole shift, solar activity gradually increases to a maximum, when the Sun is at its most exuberant.
The last solar minimum was recorded in December 2019. We are currently in a phase of increasing activity and moving toward a solar maximum around July 2025. Last year saw some truly epic outbursts, which could mean even more spectacular fireworks are in store for us this year.
No two solar cycles are the same, so it’s hard to predict exactly how active the Sun will become. Probes and observatories like the Parker Solar Probe and Solar Dynamics Observatory are helping scientists better understand our Sun’s behavior so they can better predict solar storms.
The approaching CMEs should probably reach Earth’s orbit in the next few days, and there is a high probability of geomagnetic storms and auroras over the weekend.
