Free How to Destroy the Universe by Paul Parsons Page B

you can start to hear thunder when the storm is about 16 km (10 miles) away—the bad news is this means you’re already within range of the lightning. If you’re able to, the safest course of action is to get indoors. Don’t think you’re safe under shelters and canopies. Get inside a building, where a lightning strike should be conducted safely down to the ground. But being inside doesn’t make you totally safe. Lightning can still be transmitted into your home via the electricity supply. So do not use any electrical equipmentduring a storm—most indoor injuries from lightning are sustained by people talking on the phone. If you’re away from buildings during a storm, a different strategy is needed. If your car is near then get inside and shut the door. The rubber in your tires will do little to stop an electric current that’s powerful enough to make it down through hundreds of meters of thin air. But the metal bodywork, so long as you’re careful not to touch it while you’re in there, should protect you—acting like a “Faraday cage.” British physicist Michael Faraday showed in 1836 that the electric charges within an enclosure made of conducting material will always cancel out—and if there are no charges there can be no dangerous currents. It’s the same mechanism that protects you if you’re in a plane that gets struck by lightning. The average commercial jet aircraft gets struck about once per year—just as well its aluminum skin is designed to withstand currents of up to 200,000 amps.
Out in the open
    You are at your most vulnerable when you’re out in the open. Your main concern is to stay low—literally. Lightning takes the path of least resistance, traveling through the shortest distance of air possible, which is why it always strikes the highest point above ground. Sheltering from the rain under the only tree for miles around is a very bad idea (the same applies to standing near telegraph poles and metal fences). Not only do yourisk severe burns should the tree be struck, but there is also the danger that you will get electrocuted directly thanks to a phenomenon called “side flash.” This is where the current from the lightning bolt passes directly into the ground and spreads horizontally outward. The electric charge this creates in the ground diminishes rapidly with distance. However, you may still receive a fatal surge of current through your body if you are standing close enough to where the lightning struck.
    Standing in a dense forest of trees all more or less the same height is fine. But if your friends insist on sheltering under a lone tree, you could remind them that getting wet will actually boost their survival chances. This is because of a phenomenon called external flashover, where the current passes over the victim’s body rather than through it—thus reducing the risk to the heart, brain and other organs. External flashover happens because water is an extremely good conductor, with a much lower electrical resistance than the human body.
    The best advice in open country is to crouch down (keeping as low to the ground as possible), on the balls of your feet (minimizing your contact area with the ground), and with your feet close together (to lessen the risk from side flash). Some experts even recommend putting your hands over your ears and shutting your eyes (hearing and vision injuries are common amonglightning strike victims). And should you feel the hairs stand up on your neck—a strong sign that a strike is imminent—hold your breath (some victims sustain internal burns from inhaling the superheated air). Oh, and make sure you and your friends all keep your distance while you’re crouching—lightning can hop between people standing up to 6 m (20 ft) apart. Even once a storm seems to have passed, don’t be lured into a false sense of security—charge remains in the air and