Mysterious Flashes Above Earth: New Videos Explain Sprites

[Ivan Seeking]

New Videos Help Explain Mysterious Flashes Above Earth
By Robert Roy Britt
LiveScience Managing Editor
posted: 16 February 2006
11:01 am ET

http://www.livescience.com/forcesofnature/060216_sprites.html

 

[matthyaouw]

Thats a pretty cool vid. thanks for posting it.

 

[Mk]

Pretty sweet picture (read the caption): http://www.livescience.com/php/mult...ms+University's+Moonbear+Institute+of+Biology

 

[Astronuc]

From one of the links -

http://www.space.com/scienceastronomy/planetearth/red_sprites_991208.html

The mechanics of sprites

With negative cloud-to-ground (CG) lightning strikes, electrons move from the clouds to the Earth (and, by definition, current moves upward). In a positive CG, electrons move upward. While all of this might be interesting to devoted lightning researchers, red sprite aficionados are most curious about the physics happening above the clouds. And the new research, produced by Stanford University's Christopher Barrington-Leigh and colleagues, changes the perception of what's going on up there.

"Our observation of negative CG sprites suggests that the normal mechanism for sprites does not depend greatly on the sign of the charge moved by the lightning, but only on how much charge is moved by the lightning," Barrington-Leigh told space.com. "The scarcity of negative CG sprites must then lie in the fact that most negative CG lightning just doesn't often move enough charge around."

Every second of every day, on average, lightning hits Earth about 50 times. Barrington-Leigh points out that the majority of that activity involves negative CG strikes, of the type he's just observed to be associated with red sprites. This raises the possibility that sprites may be far more prevalent than previously suspected.

The possibly higher frequency could alter our understanding of numerous upper-atmosphere phenomena. Some researchers have speculated that sprites might create nitric oxide, which destroys the protective ozone layer. And there are other possible relationships.

"We have seen evidence that sprites, and the electromagnetic pulses from lightning, may be able to both increase and decrease [respectively] the populations of high-energy particles in the Earth's radiation belts," said Barrington-Leigh. "These remarkable effects could thus affect the rate at which satellites in low- and middle-Earth orbit are being bombarded by electrons."