The most powerful solar flare in three years was expelled by the Sun on Sunday.
Ultraviolet and x-ray radiation was expelled from the M4.4 flare, which ionized the top of Earth’s atmosphere.
Flares are rated between four classifications, between background-level A-class flares, followed by B, C, M, and X-class which are the largest flares; similar to the Richter scale, each letter is tenfold more powerful than its previous, meaning an M-class flare is ten times greater than a C-class.
While the largest flare in three years, it is unlikely to have been particularly noticed except by specialists.
“Ham radio operators and mariners may have noticed strange propagation effects at frequencies below 20 MHz, with some transmissions below 10 MHz completely extinguished”, Dr. Tony Phillips of SpaceWeather wrote.
However, this could be because the sun itself blocked off some of the expulsion, with Dr Phillips suggesting that because the blast site was behind the sun’s southeastern part its body may have eclipsed some of the flare – meaning it could have been an X-class event.
The coronal mass ejection (CME) – composed of plasma and its accompanying magnetic field - was flung into space, which will fortunately not strike the Earth.
If such a blast had hit the Earth, however, the planet could experience a strong geomagnetic storm; and since the sunspot that originated the flare will rotate onto the Earthside face of the sun in a few days, such an event may be incoming in the week.
In September the sun entered a new solar cycle, which usually brings with it an increase in large flares such as this one.
The Sun’s activity will continue to increase until July 2025, when the Sun reaches its next predicted maximum, halfway through its 11-year cycle.
Its previous largest flare, which was also M-class, took place in June. This M-class flare did reportedly cause a small radio blackout, and was followed by a smaller C-class flare approximately three hours later.
