… In a day's time, the sun uncorked three X-class solar flares — all stronger than any others this calendar year.
The grand finale, which peaked at 9:11 p.m. EDT Monday night, was the most intense — an X3.2-class eruption. The flare packed the energy "equivalent to millions of 100-megaton hydrogen bombs" writes Discover's Tom Yulsman. It ranks as the third strongest flare of the current solar cycle, which began February 15, 2011, taking the spot of the second flare in the sequence (which now ranks 4th strongest).
Via NASA: "Four images from NASA's Solar Dynamics Observatory of an X3.2-class flare from late at night on May 13, 2013. Starting in the upper left and going clockwise, the images show light in the 304-, 335-, 193- and 131-angstrom wavelengths. By looking at the sun in different wavelengths, scientists can view solar material at different temperatures, and thus learn more about what causes flares."…
The ratings of the three successive flares were X1.7, X.2.8, and X3.2. These X-class flares are the strongest variety, and an X3 is three times as strong as an X1. (The other flares categories are M-class, which are medium strength, and C-class, which are small and relatively weak.)
A blast of solar wind known as coronal mass ejections (CMEs) was associated with all three flares. Of the third CMENASA writes: Experimental NASA research models show that the CME left the sun at approximately 1,400 miles per second, which is particularly fast for a CME. The models suggest that it will catch up to the two CMEs associated with the earlier flares.
None of the flares or associated CMEs were pointed at Earth, so disruptions to satellite communications and the power grid are not expected. However, the CMEs may be on a path to affect NASA's Epoxi and Spitzer spacecrafts on May 15-16….