Strongest solar flare in four years washes over Earth

BBC : Three days ago, NASA’s Solar Dynamics Observatory detected an ultraviolet flare emanating from a sunspot. Hot particles associated with the flare have already reached Earth. Although observations from two other spacecraft, STEREO-B and SOHO, suggest that the stream of particles is not powerful enough to knock out power grids, it will likely affect telecommunications on Earth, brighten and enlarge the polar auroras, and qualify as the strongest in four years.