Frenzy in the summer skies
This idealized drawing of a lightning discharge illustrates some of the things we know about lightning today. Still not definitely agreed on — although scientists are beginning to get answers — is just how clouds become electrified.
1. Positive electrical charges accumulate in upper part of thundercloud.
2. Negative charges accumulate in lower part of thundercloud.
3. Small negative “leader” stroke ionizes path to earth to permit free flow of electricity and quick release of remaining charge.
4. Violent upward flow of warm air through thundercloud, it is believed, separates negative and positive charges.
5. Principal discharge is thought to be a core of fire 14,000 centigrade.
6. Enough current for 200,000 ordinary light bulbs; enough power to hoist a 35,000-ton battleship 40 feet.
7. Storm clouds take shape of steep dome.
8. Rain occurs during downdraft.
9. Small positive leaders from earth may join negative leaders from cloud.
10. Target: anyplace, anywhere, anyone.