Space weather emanating from the sun and other stars normally goes unnoticed by us, but the effects of big solar storms can be devastating. When a solar storm of almost apocalyptic proportions destroys large parts of the world's electrical grid, thrusting our civilization back into the Steam Age and resulting in millions of casualties as our modern technological infrastructure crumbles. Chillingly, a storm like this happened only 150 years ago, but the effects on our pre-technological world were minimal. Now scientists say they would be catastrophic.