A burst of solar material leaps off the left side of the sun in what’s known as a prominence eruption. This image combines three images from NASA's Solar Dynamics Observatory captured on May 3, 2013, at 1:45 pm EDT, just as an M-class solar flare from the same region was subsiding. The images include light from the 131-, 171- and 304-angstrom wavelengths.
Image Credit: NASA/SDO/AIA
Explanation from: http://www.nasa.gov/mission_pages/sunearth/news/News050313-flare.html