SPACE - Sun emits fourth X-class flare in a week

The sun emitted a significant solar flare—its fourth X-class flare since Oct. 23, 2013—peaking at 5:54 p.m. on Oct. 29, 2013. 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 disrupts the radio signals for as long as ...

http://phys.org/news/2013-10-sun-emits-fourth-x-class-flare.htm