Video: Powerful solar flare erupts from the sun The flare came from an active region on the left side of the sun, which has already been the source of a number of weaker flares. 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. This flare was an X-class, one of the most intense kind which can cause degradation or blackouts of radio communications for about an hour. Increased numbers of flares are quite common at the moment, since the sun's normal 11-year activity cycle is ramping up toward solar maximum, which is expected in 2013. The first X-class flare of the current solar cycle occurred on Feb 15, 2011 and there have been 15 X-class flares total in this cycle, including this one.