Recently, the sunspot threw an X-class surprise flare, one of the most powerful solar flares our home star could produce. The big bang created a rare “solar tsunami” on the Sun’s surface, causing an intense burst of radiation that caused a radio blackout on Earth. And in a rare recording, a radio astronomer has managed to record the eerie sounds of a solar storm hitting our planet’s atmosphere.

The X-class flare occurred on February 17, Spaceweather.com reported. It was spat out by a nascent sunspot named AR3229. Solar storm forecasters at the National Oceanic and Atmospheric Administration (NOAA) estimated the probability of a small X-class solar flare that day, but believed the threat would come from the much larger sunspot AR3226.

As a result, astronomers were caught off guard by a 2.2-magnitude stellar explosion, Spaceweather.com reported. (The sunflare classes include A, B, C, M, and X, and each class is at least 10 times stronger than the previous one. Each class is divided into separate categories numbered 1 through 9; there is no defined upper limit.)

According to Spaceweather.com, the flare caused a rare shock wave known as a solar tsunami to propagate through the Sun’s visible surface, or photosphere. Also known by scientists as a fast magnetohydrodynamic wave, a solar tsunami is essentially a “giant hot plasma wave” in the photosphere that reaches 901,000 km/h and reaches an altitude of about 62,150 miles. (100 000 km), according to NASA.

The flare also produced a Type II solar radio flare, a stream of mostly ultraviolet and X-ray radiation that hit Earth shortly after the flare. According to Spaceweather.com, the radiation ionized the upper atmosphere, causing minor radio blackouts in parts of America for about an hour. (There are five categories of solar radio emissions. Type I is the weakest and Type V is the strongest and can cause widespread and prolonged power outages.)

Thomas Ashcraft, a New Mexico-based amateur radio astronomer and community scientist, has succeeded in making a rare audio recording of a radio burst hitting Earth. The eerie sound consists of static created by radiation entering the atmosphere and was somehow recorded by chance.

“The sun was directly in the beam of my radio telescope when the flare occurred,” Ashcraft told Spaceweather.com. This allowed the radio emission to capture “all its strength,” which would not have been possible if his telescope had not already been pointed at the sun, he added.

Class X outbreaks seem to occur more frequently. On January 3, the first of the year, a potential X-class flare exploded from a massive sunspot hidden on the far side of the Sun(opens in a new tab). Since then, the sun has fired five more X-class flares, including the latest one. For comparison, there were only seven X-class flares in all of 2022, according to SpaceWeatherLive.com.

The increase in X-class flares is likely the result of the sun entering a more intense phase of the 11-year solar cycle that is expected to peak in 2025. The increased activity also caused more sunspots to appear.