Weird Lightning
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Scientists
captured this blue-jet lightning bolt as it flashed up from the
top of a cloud. They used a night-vision camera to catch the light.
The color has been changed from “night-vision” green to blue. |
Shocking!
Two new kinds of lightning are dancing in the sky—not really new, but
scientists have just learned about these mysterious flashes.
Both of these types of lightning flash up from the tops of clouds instead of down to the ground, so people rarely see them.
For many years airplane pilots said they saw lightning shooting up from clouds, but nobody believed them. Then in 1989, a scientist used a video camera to catch lights flashing upward, above a storm.
“It became a threshold for a new field of science,” said Dr. Victor Pasko, a scientist at Penn State University. Now Dr. Pasko and other researchers have started photographing and measuring the bright pulses, which are called red sprites and blue jets.
Mysterious Red Sprites
Sprites seem to pop upward out of clouds that are also sending lightning
bolts crashing to the ground. Sprites usually appear in clusters of two,
three, or more. Some look like red jellyfish. Others look like thin red
curtains. They don’t last long. To see one, you have to be looking straight
at it. There’s no time to spot it out of the corner of your eye and then
turn to look at it.
A Blue Jet on Video
Dr. Pasko and a team of researchers captured the other newly discovered
lightning—a blue jet—on video. They were photographing a storm cloud
one night in Puerto Rico, hoping to catch a sprite or a jet.
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Dr.
Pasko and the night-vision camera in Puerto Rico. |
They saw a blue light shoot up from the top of the cloud. It went faster and faster. It split into two spikes that branched into lots of blue fingers. The blue jet flashed twice. Then it fell apart into many bright spots that glowed for a moment before fading. It was all over in less than a second.
“We just started screaming,” Dr. Pasko said. “It was the most spectacular thing I’ve ever seen.”
The scientists had caught the jet’s picture on a video recorder hooked to a computer. It’s the best movie ever made of a blue jet.
When Dr. Pasko saw the jet, he didn’t hear any thunder. Lightning makes thunder by heating the air. But up where jets and sprites flicker, the air is so thin that the electricity of a lightning bolt may not be able to heat it up.
Nobody knows for sure what causes red sprites and blue jets. But scientists think these mysterious forms of lightning will reveal secrets about Earth’s atmosphere.
