Rare form of transient luminous event over Oklahoma, US

An enormous swarm of sprites was observed across the top of a thunderstorm during a severe weather outbreak in Oklahoma, US on May 23, 2016.

The phenomenon was recorded by amateur astronomer Thomas Ashcraft, almost 640 km (400 miles) away, SpaceWeather.com reports, but it seems that on that day, at 04:18 UTC, Ashcraft recorded a very rare transient luminous event.

He points out to the "palm tree" dendritic fan shape in the midst of the sprite cluster – a possible 'pop-through gigantic jet' – and noted that the event is still being analyzed.

Video courtesy Thomas Ashcraft

Even if Ashcraft didn't record this rare event, just seeing and hearing sprites dancing high above the ground is a special treat. "The deep bass sound of the lightning stroke sounds like a distant shotgun blast in the night," he says.

Oscar van der Velde, a lightning scientist at the Technical University of Catalonia, explains a 'pop-through gigantic jet' as a cluster of sprites that can actually warp Earth's ionosphere, bringing it down from its usual altitude of 90 km (56 miles) to only 40 km (29 miles)." This sets the stage for the jet.

"The sprite cluster triggers an upward-directed discharge which in the past received fancy names as 'troll' or 'palm tree'," said van der Velde. "A satellite-based study by Taiwanese researchers in 2012 found them similar to gigantic jets – large isolated discharges reaching from the thundercloud toward the ionosphere. In the case of a 'pop-through gigantic jet,' the lowering of the ionosphere is not uniform and the jet may then reach higher than the bottom tendrils of the sprite."

SpaceWeather's Tony Philips noted in his post yesterday that most scientists did not believe sprites existed until after 1989 when they were photographed by cameras onboard the space shuttle. Nowadays, "sprite chasers" routinely photograph them from their homes.

Source: SpaceWeather

Featured image credit: Thomas Ashcraft