These pictures from NASA's Solar Dynamics Observatory show the three X-class flares that the sun emitted in under 24 hours on May 12-13, 2013. The images show light with a wavelength of 131 angstroms, which is particularly good for showing solar flares and is typically colorized in teal. Credit: NASA/SDO

The sun emitted a third significant solar flare in under 24 hours, peaking at 9:11 p.m. EDT on May 13, 2013. This flare is classified as an X3.2 flare. This is the strongest X-class flare of 2013 so far, surpassing in strength the two X-class flares that occurred earlier in the 24-hour period.

The flare was also associated with a , or CME. The CME began at 9:30 p.m. EDT and was not Earth-directed. 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.

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. Credit: NASA/SDO

The merged cloud of solar material will pass by the Spitzer spacecraft and may give a glancing blow to the STEREO-B and Epoxi spacecraft. Their mission operators have been notified. If warranted, operators can put spacecraft into safe mode to protect the instruments from solar material.