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S U D D E N     F A C T S ™
What causes lightning?

Scientists are re-thinking their theories on what causes lightning. Lightning occurs when particles of frozen water collide with ice crystals inside large clouds, generating positive and negative electrical charges, which separate within the cloud - the negative charges moving downward and the positive charges upward - and form a lightning bolt. But recent research suggests that the layers of charged particles are sometimes reversed, with positive charges sinking to lower regions, says Paul Krehbiel, a researcher at the New Mexico School of Mines and Technology. A surprising number of storms also produced an accompanying "positive to ground" form of lightning, in which positive charges rush to the ground and cause a reverse flow of negative charges -- an effect opposite of typical lightning strikes. Krehbiel says such lightning strikes tend to be more powerful, and may be more common than had been realized. "Storms may reverse their polarity all the time, but we just never knew it," he said. 

Can anything go faster than the speed of light?

Well, we always thought the answer to that was a definite NO. However, scientists reported in 2000 that they had exceeded the cosmic speed limit. In a landmark experiment, they caused a light pulse to travel at many times the speed of light, so fast that the peak of the pulse exited a specially prepared test chamber before it even finished entering it. According to the scientists, the results are "not at odds with Einstein," though on the surface they appear to contradict his theory of relativity, which holds that the speed of light in a vacuum (about 186,000 miles per second) is the fastest anything can go. Said Lijun Wang, one of the scientists at the NEC Research Institute in Princeton, NJ, who conducted the experiment: "Our experiment does show that the generally held misconception that 'nothing can move faster than the speed of light' is wrong." Nothing with mass can exceed the light-speed limit. But physicists now believe that a pulse of light, which is a group of massless individual waves, can. 

Who discovered the speed of light?

French physicist Armand Fizeau was the first to approximate the speed of light. In 1849, he obtained a value for the speed of light that was about five percent too high. Jean Foucault obtained the first accurate measurement (within just one percent of the correct speed) in 1862.

M Y S T E R Y     F A C T
TODAY'S TRIVIA QUESTION

What is a light-year?

-- Answer here next issue --

PREVIOUS TRIVIA QUESTION & ANSWER

In Greek tragedies, what is the difference between "hubris" and "hamartia"?

"Hamartia" is the fatal flaw that brings a good character to his ruin. The class example of hamartia is "hubris," or pride.