The Sun has always been a source of warmth, comfort and light. But we're discovering a new and frightening side to our star. A kind of solar rage peaks every eleven years. And sometimes, Earth is in the line of fire. It's a billion pounds of matter traveling at a million miles an hour - a solar blast - which could send us scrambling. Without warning, navigation systems could be disrupted, blinding jets in the sky. Phone connections around the world could go dead, leaving us stranded during emergencies. And within minutes of impact, a power blackout could leave millions of people in the dark.