Watch this giant sunspot erupt in powerful solar flare barrage (video)

The sun has released an almost non-stop barrage of solar flares in the past 24 hours, including nine powerful M-class flares.

AR3311 is joined by another huge sunspot — AR3310 — which was responsible for the colossal solar flare on May 16 that caused widespread radio blackouts. The volatile pair are slowly rotating into view and will be directly facing us by the weekend.

a gif showing a series of solar flares erupting from the sun. — The sun has released multiple powerful solar flares in the past 24 hours. (Image credit: NASA/SDO)

Solar flares are caused when magnetic energy builds up in the sun's atmosphere and is released in an intense burst of electromagnetic radiation. They are categorized by size into lettered groups, with X-class being the most powerful. Then there are M-class flares that are 10 times smaller than X-class flares, then C-class, B-class and finally A-class flares which are too weak to significantly affect Earth.

Within each class, numbers from 1 to 10 (and beyond, for X-class flares) denote a flare's relative strength. The strongest flare in the last 24 hours clocked in at M5.3 at 8:40 p.m. ET on May 18 (00:40 GMT on May 19).

sunspots rotating into view across the disk of the sun. — On the left is AR3310, which produced the M9.6 flare on May 16. On the right is AR3311, which has produced a barrage of M-flares in the last 24 hours. (Image credit: NASA/SDO)

A series of shortwave radio blackouts have been triggered by the fusillade of flares, sending a strong pulse of X-rays and extreme ultraviolet radiation barrelling toward Earth. Traveling at the speed of light, the radiation reaches Earth in just over eight minutes and ionizes the upper layer of Earth's atmosphere — the thermosphere — triggering shortwave radio blackouts on the sun-lit portion of Earth at the time of impact.

Solar activity is on the rise as part of solar cycle 25, which scientists predict will peak in 2025. To find out if there is a solar flare today and to keep up with the latest space weather findings, visit the National Oceanic and Atmospheric Administration's Space Weather Prediction Center to see the most recent solar X-ray data from the agency's GOES weather satellites that perch over the eastern and western U.S.

Daisy Dobrijevic joined Space.com in February 2022, having previously worked as a staff writer for All About Space magazine. She completed an editorial internship with BBC Sky at Night Magazine and worked at the National Space Centre, communicating space science to the public.

Daisy holds a PhD in plant physiology and a Master's in Environmental Science. Based in Nottingham, U.K., she covers all things space, with a special focus on solar activity and space weather. She also has a keen interest in astrotourism and is always on the lookout for the next northern lights adventure.

She will be a guest speaker aboard HX's Solar Eclipse Expedition in August 2026 and will join Hurtigruten as an onboard astronomer for a northern lights sailing in January 2027.