NASA astronaut Butch Wilmore has captured an image of a blue jet sprite in the Earth’s atmosphere, a rare phenomenon only confirmed in recent years.
Astronaut and keen astrophotographer Don Pettit shared a photo to Reddit, taken by colleague Butch Wilmore during his unexpectedly long stay on board the International Space Station (ISS).
“Here is a blue jet-sprite photographed by my crewmate Butch Wilmore in a timelapse sequence,” Pettit explained in a reddit post. “Blue jets and sprites are terms that are rather loosely applied to what I like to call ‘upward directed lightning’ (UDL). This is a rather new elusive atmospheric phenomena now extensively captured by digital cameras but still not fully understood. The tops of this UDL are around 75-80km [47-50 miles], boarding on the fringes of space.”
The phenomenon, as explained by Pettit, is not fully understood. Blue jets and red sprites have been reported by credible witnesses on the ground, as well as pilots in the air, for decades. According to accounts of the blue jet phenomenon, blue or green columns of light can sometimes be seen emanating upwards from the top of thunderstorm clouds at great speeds. Despite this, we have only relatively recently confirmed their existence.
“The phenomenon, now known as a sprite, was first accidentally documented on ground based videotape recordings on the night of July 6, 1989. Video observations from the space shuttle acquired from 1989 through 1991 provided 17 additional examples to confirm the existence of the sprites phenomenon,” NASA explains.
Like regular lightning strikes, the sprites occur following a build-up of electrical charge within clouds. Unlike usual lightning, the charge proceeds upwards, the result of a layer of negative charge above. The color occurs as the charge meets nitrogen in the Earth’s atmosphere.
While we have a reasonable understanding of the jets and sprites, and their similarities to lightning, a lack of observations means there is still much to learn.
“What conditions in the upper atmosphere trigger sprite initiation?” NASA asks, as well as “how are sprites connected with gravity waves, which send wind-driven ripples of energy through our upper atmosphere?”
Further study – from below and above – may help answer these questions.
