Universe Today
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Over 90% of UFO sightings can be easily explained, and are usually visual misinterpretations of meteors, weather balloons, a flock of birds, blimps, or even the Moon. Here's one more to add to the list of items mistakenly identified as UFO's: sprites. No, not the elf or troll-like sprites, but a natural phenomenon which occurs during thunderstorms. "Sprites appear above most thunderstorms," said Colin Price of the Tel Aviv University, "but we didn't see them until recently. They are high in the sky and last for only a fraction of a second." While there is much debate over the cause or function of these mysterious flashes in the sky, Price says they may explain some bizarre reports of UFO sightings.
Sprites are described as flashes high in the atmosphere, between 35 and 80 miles from the ground, much higher than the 7 to 10 miles where regular lightning bolts usually occur.
"Lightning from the thunderstorm excites the electric field above, producing a flash of light called a sprite," explained Price, head of the Geophysics and Planetary Sciences Department at Tel Aviv University. "We now understand that only a specific type of lightning is the trigger that initiates sprites aloft." [caption id="attachment_26095" align="aligncenter" width="400" caption="The appearance of a "sprite" (about 30 miles high by 30 miles wide), flashing above a distant thunderstorm. The "sprite" is about 175-250 miles away from the camera. Credit: ILAN Science Team"]
[/caption] Though sprites have existed for millions of years, they were first discovered and documented only by accident in 1989 when a researcher studying stars was calibrating a camera pointed at the distant atmosphere where sprites occur.
"Sprites, which only occur in conjunction with thunderstorms, never occur on their own, and are cousins to similar natural phenomenon dubbed by atmospheric electricians as 'elves,' 'goblins' and 'trolls,'" said Price. These flashes are so named because they appear to "dance" in the sky, which may explain some UFO sightings.
Price and has led students and other researchers in studying sprites for several years, and Tel Aviv University has been one of the leaders in researching the phenomenon. Now, Price and his students are teaming up with students from The Open University and The Hebrew University to take three-dimensional pictures of sprites to gain a better understanding of their structure. Using remote-controlled roof-mounted cameras, the researchers are able to look at the thunderstorms that produce sprites when they are still over the Mediterranean Sea.
Using new camera techniques has revealed the sprites' circular structures, which are much like those of candles on a birthday cake. Using triangulation, Price and his team have also been able to calculate the dimensions of the sprites' features. "The candles in the sprites are up to 15 miles high, with the cluster of candles 45 miles wide -- it looks like a huge birthday celebration!"
Because of their high altitude, sprites may also have an impact on the chemistry of the Earth's ozone layer. "Since they are relatively infrequent, the global impact is likely small," said Price. "But we're researching that now."
Source:
PhysOrg
