The Sun appears to be stirring once more following one of its most energetic years in 2024. During the weekend leading up to May 5, 2025, Earth experienced exceptionally swift solar winds, reaching speeds over 700 kilometers per second, which resulted in minor G1-class geomagnetic storms and spectacular auroras in high-latitude areas.
This increase in solar wind is associated with a massive coronal hole on the Sun, a region where the solar magnetic field opens and permits fast streams of charged particles to flow into space and reach Earth. In spite of the strong solar wind, the Sun’s largest visible sunspot, AR4079, remains unexpectedly calm.
Typically, a sunspot of this magnitude would generate strong solar flares, yet AR4079 has only released a few minor C-class flares up to now. This unexpected tranquility has confused solar researchers, prompting the inquiry: might this be a lull before a storm or merely a peaceful period?
A notable characteristic of sunspot 4079 is a striking “light bridge”—a luminous, canyon-like formation cutting through the sunspot’s dark center. Solar physicists observe that light bridges frequently suggest intricate magnetic activity below the surface, where magnetic fields intersect and reconnect, processes capable of triggering strong solar flares.
Nonetheless, a light bridge’s existence does not ensure an upcoming explosion; occasionally, sunspots featuring light bridges merely disintegrate silently. The existing solar wind conditions, influenced by the coronal hole, have already triggered geomagnetic storms that disrupted Earth’s magnetic field and initiated auroras visible as far south as northern US regions.
Though there haven’t been any significant coronal mass ejections (CMEs) targeting Earth lately, the persistent high-speed solar wind is still compressing Earth’s magnetosphere, raising the likelihood of additional geomagnetic activity.
