A rare solar storm, S4, is hitting Earth's atmosphere: Russian scientists warn

In an exceptional astronomical event, the likes of which haven't been seen in scientific records for nearly two decades, scientists from the Solar Astronomy Laboratory at the Space Research Institute of the Russian Academy of Sciences observed a powerful solar radiation storm classified as level S4. This storm has begun to have a direct and strong impact on the space environment surrounding Earth, marking a new peak in current solar activity.

Details of the rare astronomical event

Data released by researchers revealed a sudden and sharp surge in the solar proton flux, exceeding 10,000 units, a level not observed for over two solar cycles. Scientists confirmed that the storm reaching S4 level is unprecedented in nearly 20 years, placing this event among the most significant astronomical phenomena of the last decade.

Scientists classify radiation storms using a scale ranging from S1 (lowest) to S5 (highest). While level S5 is considered a theoretical limit that has never been recorded in modern observations, level S4 represents a "severe" radiation storm, while the historical record set in the last century still stands at approximately 40,000 units.

X-class solar flare and its effects

These violent cosmic disturbances are the aftershocks of a massive solar flare that occurred last Sunday, classified as an X-class flare, the most intense and powerful category on the solar flare scale. This flare, the first of its kind since early 2026, unleashed a torrent of charged particles toward Earth, registering the highest flow rate in the last ten years.

Russian laboratory experts pointed out that this event raises profound scientific questions, as overall solar activity - despite its increase - is still below the traditional levels that usually explain such a violent radiation explosion, indicating complexities in the dynamics of the sun that are still being studied.

Potential effects and risks

From a scientific standpoint, storms of level (S4) have significant impacts on space technology and the environment. These impacts include the potential for interference with satellite memory systems, increased noise in space imaging data, potential radiation risks to astronauts outside Earth's atmosphere, and disruptions to high-frequency (HF) radio communications, particularly in polar regions.

Solar Cycle 25: Activity exceeding expectations

Scientists have described the conditions that led to this barrage of radiation being directed straight at our planet as an “extremely rare coincidence” resulting from a confluence of exceptional physical circumstances. This occurred during solar cycle 25, which began in December 2019.

Solar cycles are a natural, cyclical process in which the Sun's magnetic field changes approximately every 11 years. Despite initial predictions that cycle 25 would be relatively calm, it proved to be the most turbulent and active in decades, registering an unexpected peak in strength. This necessitates continuous monitoring by global space agencies to protect Earth's technological infrastructure.