On October 15, during a teleconference with reporters, representatives from NASA, the National Oceanic and Atmospheric Administration (NOAA), and the International Solar Cycle Prediction Commission announced that the Sun had entered solar maximum in cycle 25. This 11-year activity cycle high will continue through the next year.
Image source: NASA
The solar cycle is a natural process that the Sun goes through, changing its magnetic activity from low to high and back again. The Sun has longer cycles – hundreds and even thousands of years long – but the most studied are the 11-year cycles. At the height of each of them, the magnetic poles of the Sun change places, and the star passes from a quiet state to an active one.
After some time, the activity of the Sun decreases to its minimum and solar minimum occurs. Scientists never know in advance exactly what will happen when. We can only talk about an 11-year cyclicity conditionally. For example, from the current period – the 25th since tracking these cycles – the maximum was expected to occur in the second half of 2025, but it happened already in the fall of 2024.
During periods of greatest activity on the Sun, the number of sunspots increases. They are formed in places of the highest concentration of electromagnetic field lines of a star. In such areas, the convection of solar masses from the depths to the surface slows down, causing a specific area of the surface to become slightly cooler than neighboring areas. When magnetic lines then rapidly switch and open in such places, flares occur that can be accompanied by a coronal mass ejection from the Sun.
On the left is the Sun in December 2019 (minimum activity), on the right is the Sun in May 2024 (approaching maximum activity)
«This announcement does not mean this is the peak solar activity we’ll see this solar cycle, says NOAA meteorologist Elsayed Talaat. “Although the Sun has reached solar maximum, the month when solar activity peaks cannot be determined for several months or years.”
«We cannot reliably predict solar cycles,” explained astrophysicist Michael Wheatland from the University of Sydney in Australia back in 2022. “We don’t fully understand the solar dynamo, which generates the magnetic fields visible on the surface as sunspots that cause flares. This is one of the unsolved problems of astrophysics.”
But scientists have learned to determine and separate the phases of the 11-year cycle of solar activity using indirect signs. For example, by the intensity of the appearance of sunspots and the intensity of flares on it. So, in early October, a flare of magnitude X9.0 occurred on the Sun. This is not the most powerful event in the entire history of cycle observations, but it is among the 20 most intense. For humans on Earth, this event passes without a trace. Not a single medical study has found a connection between solar flares and the geomagnetic storms they generate that affect people’s well-being.
The danger of flares lies in the interruption of short-wave communications on the illuminated side of the Earth shortly after the flare (if it is directed towards our planet), as well as in an extra dose of radiation for pilots and cosmonauts and in disruption of the operation of satellites. If a coronal mass ejection occurs towards the Earth, a cloud of charged particles envelops the Earth and rushes to the poles, where colorful auroras appear. In extended metal structures on Earth – in pipelines, rails and power lines – at such moments a direct current appears, which can damage associated equipment. For example, there were cases of fire at substations. Today there are proven engineering solutions for this and this should not come as a surprise. Unless the flash and mass ejection will be of such power that technologically advanced humanity has not yet encountered, and such events have happened more than once in the history of the Earth. Let’s hope that we are not “lucky” to experience something extreme.