Solar flares are brief, enormous outbursts of electromagnetic radiation from the Sun lasting from minutes to hours.
They produce enhanced emission in all wavelengths across the electromagnetic spectrum, including radio, optical, UV, hard and soft X-rays, and gamma-rays.
Researchers classify solar flares according to their brightness in the X-ray wavelengths.
There are three categories of solar flares: C, M, and X.
C-class flares are small with few noticeable consequences here on Earth.
M-class flares are medium-sized; they generally cause brief radio blackouts that affect Earth’s polar regions. Minor radiation storms sometimes follow an M-class flare.
Compared to C- and M-class events, X-class flares are big; they are major events that can trigger radio blackouts around the whole world and long-lasting radiation storms in the upper atmosphere.
The March 11 event is classified as an X2.2-class flare (an X2 is twice as intense as an X1, an X3 is three times as intense, etc). The flare shot out from a sunspot classified asActive Region 12297, an area that had been firing off less intense flares for a few days prior to the massive, X-class eruption on Wednesday. According to the US Space Weather Prediction Center out of Colorado, which is overseen by the National Oceanic and Atmospheric Administration,the flare caused an area-wide blackout that lasted up to an hour in some regions, with high-frequency radio communications faltering as a result.
SDO observatory, which watches the Sun constantly, captured an image of the event.
The sun released an X-class flare, an X2.2, on March 11, 2015. In this video, the flare itself is not very impressive. However, solar material can be seen blasting away from the flare location. Credit: NASA/SDO.