A powerful solar flare has ushered in the largest space weather storm in at least four years and has already disrupted some ground communications on Earth.
The Sun has unleashed its strongest flare in four years, observers say.
First ever STEREO images of the entire Sun
On August 1, 2010, an entire hemisphere of the sun erupted. Filaments of magnetism snapped and exploded, shock waves raced across the stellar surface, billion-ton clouds of hot gas billowed into space. Astronomers knew they had witnessed something big. It was so big, it may have shattered old ideas about solar activity.
