Had Ben Franklin fried himself in his lightning experiment, we might see Chester Arthur on the one-yard bill.

Thinking that lightning was an electric current, Franklin flew a kite in a thunderstorm in 1752. If you've been reading this far, you probably wonder why the ol' boy wasn't fried when his hand approached an iron key hanging from the kite string.

Luckily, the current passed through Ben's bod and into the ground without major harm. Although we'd hate to run that experiment past a human-subjects review board, Benny proved his point -- that lightning was an electric charge in the cloud.

Just think: had Franklin cooked his goose -- as well he might have -- they might have put Chester Arthur on the $100 bill!

These days, researchers are a bit more chary in their lightning research -- but they have much cooler tools -- both on satellites and the ground.

If you're scared of lightning, avoid the Southeast United States, Southern Africa and parts of South America. These data, from the Lightning Imaging Sensor on the Tropical Rainfall Measuring Mission, show summer in the Southern Hemisphere. Courtesy: NASA

Cloudy picture
New studies are probing the significance of cloud flashes -- current between regions of clouds with opposite charges that does not hit the ground.

Formerly disregarded because they don't kill people, cloud flashes are getting some respect simply because they are the most common type of lightning. "We have pretty solid evidence," says David Rust of the National Severe Storms Lab, "that in a lot of storms, especially the big ones, that a very high percentage of total lightning, sometimes all the lightning, is cloud flashes for periods of time."

It makes sense because lightning gives a clue to how much energy the storm is generating (remember that lightning results from strong updrafts that separate out electrical charges in a thunderstorm). Indeed, a satellite instrument called the optical transient detector correlated tornadoes with cloud flashes.

Two minutes of lightning on June 29, 2000, during an hour of lightning that preceded a small tornado that touched ground for 15 minutes. The lightning "hole" at left (on west side of the storm) was 9 kilometers across. Similar holes appeared in several other storms. Most cloud-to-ground flashes in this storm had the newly recognized positive polarity.
Courtesy: STEPS

In a 2000 study of lightning in the Great Plains, STEPS, the Severe Thunderstorm Electrification and Precipitation Study, observed an intriguing "lightning hole" in places that spawned tornadoes.

Like the linkage between lightning rates and tornadoes, this is only a first step toward the ultimate goal: understanding thunderstorms well enough to better predict tornadoes and dangerous lightning.

How about a tool for more learning: a lightning bibliography.