Upward-shooting 'blue jet' lightning spotted from International Space Station
By Nicoletta Lanese - Staff Writer 4 days ago
(Image: © European Space Agency)
Scientists on the International Space Station spotted a bright-blue lightning bolt shooting upward from thunderclouds.
Blue jets can be difficult to spot from the ground, since the electrical discharges erupt from the tops of thunderclouds. But from space, scientists can peer down at this cerulean lightshow from above. On Feb. 26, 2019, instruments aboard the space station captured a blue jet shooting out of a thunderstorm cell near Nauru, a small island in the central Pacific Ocean. The scientists described the event in a new report, published Jan. 20 in the journal Nature.
The scientists first saw five intense flashes of blue light, each lasting about 10 to 20 milliseconds. The blue jet then fanned out from the cloud in a narrow cone shape that stretched into the stratosphere, the atmospheric layer that extends from about 6 to 31 miles (10 to 50 kilometers) above the Earth's surface.
Blue jets seem to appear when the positively-charged upper region of a cloud interacts with the negatively charged boundary between the cloud and the air above, according to the report. The blue jet appears as a result of this "electric breakdown," where the opposing charges swap places in the cloud and briefly equalize, releasing static electricity. However, the properties of blue jets and the altitude to which they extend above clouds "are not well characterized," the authors noted, so this study adds to our understanding of the dramatic phenomenon.
Blue jets seem to appear when the positively-charged upper region of a cloud interacts with the negatively charged boundary between the cloud and the air above, according to the report. The blue jet appears as a result of this "electric breakdown," where the opposing charges swap places in the cloud and briefly equalize, releasing static electricity. However, the properties of blue jets and the altitude to which they extend above clouds "are not well characterized," the authors noted, so this study adds to our understanding of the dramatic phenomenon.
Four of the flashes preceding the blue jet came with a small pulse of ultraviolet light (UV), the scientists noted. They identified these emissions as so-called "elves," another phenomenon seen in the upper atmosphere.
More:
https://www.livescience.com/blue-jets-of-lightning.html
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