This image, showing an X1.0 class solar flare flash in the center of the sun, was captured on October 28, by NASA's Solar Dynamics Observatory. It shows a blend of light from the 171 and 304 angstrom wavelengths. Solar flares are powerful bursts of radiation. Harmful radiation from a flare cannot pass through Earth's atmosphere to physically affect humans on the ground however, when intense enough, they can disturb the atmosphere in the layer where GPS and communications signals travel. Photo courtesy of NASA