The sun has had an active few days, firing several powerful solar flares and plumes of searing-hot solar material out into space.

On May 13, a sunspot on the sun’s surface named AR4086 exploded, releasing an X1.2-class solar flare, part of the most powerful category of flare. Then, during the early hours of May 14, another sunspot named AR4087 spat out an M5.3 flare, followed by an even more powerful X2.7 flare, and yet another M7.7 flare a few hours later. The radiation of these solar flares triggered radio blackouts on the sun-facing side of the planet at the time of the flares, affecting North and South America, Europe, Africa, the Middle East, and Southeast Asia.

Solar flares are sudden, intense bursts of electromagnetic radiation released from regions of intense magnetic activity on the sun’s surface, usually from or near sunspots. The sun’s surface is threaded with powerful magnetic fields, and sometimes these magnetic field lines get twisted and tangled. When the stress on these field lines becomes too great, they can snap and realign, releasing a massive amount of stored magnetic energy as a solar flare.

Some solar flares are much more powerful than others. NOAA’s Space Weather Prediction Center categorizes solar flares as either A, B, C, M, or X-class, with each class representing a ten-fold increase in power over the previous one. X-class flares are the most powerful and least common form of solar flare. The number after the letter class indicates further how strong the flare is: an M9 flare is nine times more powerful than an M1 flare. The X1.2 and X2.7 flares were on the lower end of this most intense category; the strongest recorded flare in the last seven years was an X9 in October 2024.

These newly-launched X-class flares were the first of their kind recorded since March, according to Live Science’s sister site Space.com. Solar flares cause radio blackouts because of the intense X-ray and ultraviolet radiation unleashed on our planet’s atmosphere. Normally, shortwave radio signals — used for long-distance communication — bounce off the ionosphere, allowing them to travel far across the globe. The radiation of a solar flare increases the ionization (charging) of atoms and molecules in the lower ionosphere, especially in a region called the D-layer, meaning that the D-layer absorbs radio signals instead of reflecting them, especially those in the high-frequency range.

X-class solar flares can cause radio blackouts across the sunlit side of the Earth, impacting mariners, aviators, and also triggering satellite navigation errors.