X1.1 Solar Flare Triggers Moderate Geomagnetic Storm Near Solar Cycle Peak

Earth registered the onset of a G2.3-class geomagnetic storm, classified as moderate intensity, on the evening of December 10, 2025, following the arrival of a solar plasma ejection. This event was the second significant ejection from the Sun between December 7 and 8, 2025, according to reports from the Solar Astrophysics Laboratories of IKI RAN and ISF SO RAN. Initial scientific attention had focused on the first ejection, associated with an M8.1 flare, which models suggested would miss the planet.

The subsequent impact, however, resulted from an unexpectedly dense and swift plasma ejection linked to the sole X1.1-class solar flare observed during December, which erupted on December 8. The arrival of this plasma flow caused a pronounced reaction in Earth's magnetosphere, notably manifesting as a vividly bright polar oval. Specialists pinpointed the primary impact zone over Scandinavia, noting that the periphery of the affected area encompassed territories including the southwestern regions of Russia before the disturbance tracked toward Canada. Experts indicated that a more severe geomagnetic event was averted as the Earth was only marginally grazed by the edge of the ejected plasmoid, despite the G2.3 classification.

This incident highlights the unpredictable nature of solar activity near the predicted peak of Solar Cycle 25. Researchers noted that the trajectory of the plasma from the X1.1 flare was not accurately represented in existing space weather models, which impeded precise long-term forecasting capabilities. The X1.1 flare on December 8 also generated significant radio interference, reaching an R3 (strong) level across Australia and East Asia on that date. As of December 11, 2025, the scientific community anticipated a gradual return to quiescent geomagnetic conditions. This event followed a predicted G2-G3 storm for December 9-10 that did not materialize, underscoring the month's erratic solar behavior.

The G2-level storm conditions, while moderate, carry potential effects on technological infrastructure, including temporary disruptions to satellite systems, GPS signals, and radio communications. For space-sensitive individuals, experts on the morning of December 11 recommended mitigating physical and emotional strain during the first half of the day, prioritizing hydration, and adhering to a rest regimen due to residual magnetic storm effects. The scientific community continues to monitor the environment, noting the observation of a rare 'dark' flare ejection in December, which adds complexity to understanding current solar dynamics.

In parallel astronomical developments, the interstellar comet 3I/ATLAS, discovered on July 1, 2025, has drawn attention. Observations using the ALMA observatory revealed record-high concentrations of methane and cyanide, with a methane ejection rate reaching 40 kg per second. Harvard astrophysicist Avi Loeb has suggested that anomalies in 3I/ATLAS's orbit and chemical makeup could indicate it is a technological artifact, though most scientists classify it as a natural comet. The comet's maximum approach to Earth is projected for December 19, 2025, at approximately 270 million kilometers, allowing for continued observation until its departure from the Solar System by the year's end.