Sun unleashes 2025's most powerful solar flare, causing widespread radio blackouts

It was a quiet dawn until the sun made its voice heard. As early risers began their Tuesday, the sky above flared with activity. At 4:25 a.m. EDT (0825 GMT) on May 14, the Sun released a powerful X-class solar flare, catching scientists and radio operators by surprise.

The eruption came from a new and active sunspot region, labelled AR4087, which has just started turning towards Earth. The burst caused strong R3-level radio blackouts across much of Europe, Asia, and the Middle East — all on the sunlit side of the planet when the flare struck.

According to the NOAA Space Weather Prediction Centre, this kind of solar activity is rare. Solar flares are classified in five main groups — A, B, C, M and X — with X being the strongest. This latest event measured X2.7, placing it at the lower end of the highest category. Still, the flare carried enough power to send X-rays and extreme ultraviolet radiation rushing to Earth at light speed, disturbing the upper atmosphere and affecting high-frequency radio signals used for communication.

While the full impact of the flare is still being assessed, experts say there may also have been a coronal mass ejection, or CME — a large release of solar plasma and magnetic energy that often follows strong flares. If confirmed, it could eventually lead to geomagnetic storms and colourful auroras, but only if the ejection hits Earth directly. For now, AR4087’s position near the edge of the Sun means our planet is out of its firing line.

Vincent Ledvina, a well-known aurora chaser, posted on X (formerly Twitter) that the region appears to be heating up quickly. “This is getting intense,” he wrote, adding that the same sunspot also released an M5.3 flare only a few hours earlier. “What does this AR have planned over the next days … we’ll have to wait and see.”