One of the biggest disasters we face would begin about 18 hours after the sun spit out a 10-billion-ton ball of plasma--something it has done before and is sure to do again. When the ball, a charged cloud of particles called a coronal mass ejection (CME), struck the Earth, electrical currents would spike through the power grid. Transformers would be destroyed. Lights would go out. Food would spoil and--since the entire transportation system would also be shut down--go unrestocked.