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Sunspot region 4366 turned to face Earth in early February, showing no signs of weakening and demonstrating it was the most active sunspot of the current solar cycle (cycle 25). A large coronal mass ejection (CME) released toward Earth at the time prompted a geomagnetic storm watch. A glancing blow from that CME was considered likely, and NOAA predicted that a minor (G1) geomagnetic storm could begin as early as February 5, potentially making auroras visible at lower latitudes than usual.
A huge sunspot named Region 4366 had turned to face Earth. It showed very strong activity at the time and was the most active area in the current solar cycle. Experts from the National Oceanic and Atmospheric Administration issued warnings, stating that a large burst of solar material could hit our planet. This burst, called a coronal mass ejection, could start a small geomagnetic storm later that week. If the path stayed the same, the northern and southern lights could have been seen much closer to the equator, in places where these lights are usually only seen near the poles.
This sunspot grew very fast since it first appeared, reaching about half the size of the famous spot from the 1859 Carrington Event, the strongest solar storm ever recorded. Because Region 4366 grew so quickly, it became very unstable. In just two days from Sunday to Monday of that period, it erupted more than 20 times. These eruptions included 23 M-class flares and four very strong X-class flares. NASA said this was some of the biggest solar activity seen in years.
The activity became very strong on Sunday at 6:57 p.m. Eastern Time when an X8.1-class flare exploded. This was the strongest single flare recorded since an X9.0 event in October of the previous year. The bright burst of radiation caused radio blackouts across the South Pacific and pushed a large cloud of hot gas toward Earth. Experts at the time thought this cloud would miss a direct hit but could still graze our planet. Even a slight touch could disturb Earth's magnetic shield.
If charged particles from such a cloud hit Earth's magnetic field, they travel to the poles. This makes molecules high in the upper atmosphere glow, creating the dancing lights we call auroras. A grazing hit could push the light ring closer to the equator, meaning people at more temperate latitudes might see these lights.
Sunspots are dark, cooler areas on the sun's surface. Scientists call this layer the photosphere. They form where the sun's magnetic fields get very strong and rise up. These strong fields stop normal heat flow, making the spot look dark. These areas have very unstable magnetic fields. When the twisted magnetic lines snap and reconfigure, they release huge energy.
This energy comes in two forms. The first is a solar flare, a bright flash of high-energy radiation. It travels at the speed of light and reaches Earth in eight minutes. The second form is a coronal mass ejection, or CME. This is a slower but much larger release of magnetic gas. A CME carries billions of tons of material into space at millions of miles per hour, taking one to three days to reach Earth.
Solar activity follows an 11-year cycle. The sun's magnetic poles flip direction during this cycle. At the peak, called solar maximum, storms happen more often and are stronger. NASA confirmed the sun entered this phase in 2024. Scientists expect high levels of space weather to continue into 2026. This period increases the chance of extreme events that could affect our world.
The serious effects of solar storms go far beyond the lights. Strong radiation can change the upper air layers, disrupting high-frequency radio used by planes, ships, and emergency teams. It also causes radio blackouts, like those from the recent X8.1 flare. Geomagnetic storms can create electric currents in long wires on the ground, including power grids and oil pipelines. In severe cases, this can damage transformers, potentially causing power outages for days or weeks.
Satellites orbiting Earth are very vulnerable to this weather. Energetic particles can break sensitive electronics, damage solar panels, and disrupt signals, affecting the Global Positioning System (GPS) billions of people use every day. Astronauts on the International Space Station must take shelter in shielded areas during major radiation events to stay safe.
The benchmark for extreme space weather is the Carrington Event of September 1859. A massive flare and CME caused that storm, producing auroras so bright people could read newspapers as far south as the Caribbean. Telegraph systems failed globally, and some operators received electric shocks. A storm like that today would be far more dangerous, as our modern world relies on fragile systems. Such an event could cause trillions of dollars in damage, with recovery potentially taking years.
The recent surge in activity shows the sun is active. A study looked at the sunspot that made auroras visible as far south as Florida in May of the previous year. That spot lasted over three months and released nearly 1,000 flares. Region 4366 had already released stronger flares than previous record-breaking events from that period. It was not yet known if it would last as long or produce as much energy.
Agencies like the NOAA Space Weather Prediction Center track this activity using many observatories in space and on the ground. They measure flare strength and model where CMEs go, allowing them to warn satellite operators and power grid managers. It is hard to predict the exact time of a CME impact, but predictions improve as the cloud moves closer. At the time, scientists watched Region 4366 closely. It takes about two weeks for a spot to move across the sun, and its future activity would determine if it became a major event in solar cycle 25. No matter the result, this activity demonstrates the power of our star and the link between our sun and modern technology.