WHAT IS LIGHTNING? Lightning is a form of static electricity. We experience static electricity every time we drag our feet on the carpet and then touch a conducting surface, like a metal doorknob. The shuffling causes our bodies to pick up extra electrons. Touching something with a positive charge, like metal, causes the electrons to "jump" across the small gap from our fingers to the object, and we experience a tiny electric shock. Similarly, lightning occurs because clouds become negatively charged as the water droplets inside rub up against each other during the natural process of evaporation and condensation, when moisture accumulates in the clouds. This charge seeks out something with a positive charge -- the ground, ideally -- and the lightning is the "spark" closing the gap between the two.
WALKING ROCKS: Rocks on an area of Mars were found in strangely orderly patterns. Scientists found that the rocks moved into these patterns by rolling into the wind. When the wind blows, it picks up sand in front of the rocks and pulls it away, leaving a small cavity. As the wind continues to blow, it pulls enough sand from under the rock that it rolls forward into the hole due to gravity. As the rocks move, they can block the wind from other rocks, which leaves wind rushing past the side of a rock, where it can create a hole and cause a rock to migrate laterally, helping to form a regular pattern that is repeated around Mars.
The American Astronomical Society, the American Meteorological Society, the American Geophysical Union and the American Physical Society contributed to the information contained in the TV portion of this report.