Studies funded by national laboratories have estimated that a powerful solar disturbance could knock out electrical service to over a hundred million people, causing trillions of dollars in damage.
Functional-imaging studies of the brain have revealed another tantalizing clue: During the aura phase, a wave of electrical activity sweeps over the outer, furrowed layer of the brain known as the cortex, at a pace of 2 to 3 millimeters per minute.