Scientists have finally gotten a clear view of the spark that sets off an exotic type of lightning called a blue jet.
Blue jets zip upward from thunderclouds into the stratosphere, reaching altitudes up to about 50 kilometers in less than a second. Whereas ordinary lightning excites a medley of gases in the lower atmosphere to glow white, blue jets excite mostly stratospheric nitrogen to create their signature blue hue.
Blue jets have been observed from the ground and aircraft for years, but it’s hard to tell how they form without getting high above the clouds. Now, instruments on the International Space Station have spotted a blue jet emerge from an extremely brief, bright burst of electricity near the top of a thundercloud, researchers report online January 20 in Nature.
Understanding blue jets and other upper-atmosphere phenomena related to thunderstorms, such as sprites and elves, is important because these events can affect how radio waves travel through the air — potentially impacting communication technologies, says Penn State space physicist Victor Pasko, who was not involved in the work.