According to the data coming from the NASA GOES-16 space satellite of the Geostationary Operational Environmental Satellite program, on April 20, an M-class flare occurred on the Sun. It lasted 5 minutes and ended by moving to C-class, and its peak was M1.11.
The extreme ultraviolet flare was accompanied by a coronal mass ejection, which, according to the forecasts of NASA’s Integrated Space Weather Analysis System, is not directed towards the Earth.
This is one of the most powerful outbreaks in a very long period of their complete absence. A pulse of X-rays and ultraviolet radiation from the flare ionized the upper atmosphere of the Earth, causing a blackout of shortwave radio communications over the Pacific Ocean. Mariners and radio amateurs in the area may have noticed unusual propagation conditions below 10 MHz.
This is the fourth point in the five-point flare system (only class X flares are above the M class). This outbreak is unique, because we have fallen into a very deep minimum of solar activity and recently there have been four or five such outbreaks. The Flash Activity Index has been raised from green to yellow.
The last time flares of such and greater strength were recorded on our star on November 29, 2020, and before that – only in the fall of 2017.
Astronomers have already said that the outbreak does not pose a threat to earthlings, but a massive magnetic storm may follow. Presumably, it will take place on April 21-22.
However, there is still no exact forecast. We need to wait for additional data from SOHO coronagraphs to confirm the direction of the CME ejection towards the Earth.
Solar flares, depending on the power of X-ray radiation, are divided into five classes: A, B, C (weak), M (medium) and X (strong).
Plasma clouds ejected during flares lead to geomagnetic storms and also create aurora, most often near the poles.