A team of American researchers has captured a rare film of a ‘gigantic jet’, and managed to confirm that this strange, upside-down lightning is just as powerful as the strikes that come down from clouds.

Gigantic jets flow upwards from clouds towards the outer reaches of the atmosphere, rather than down to the ground. They have been captured on film only five times since 2001, says the US National Science Foundation.

Now Steven Cummer, of Duke University in North Carolina, and his colleagues have managed to work out just how much charge these jets transfer from storms to the ionosphere.

“Our measurements show that gigantic jets are capable of transferring a substantial electrical charge to the lower ionosphere,” he says (NSF press release).

“They are essentially upward lightning from thunderclouds that deliver charge just like conventional cloud-to-ground lightning. What struck us was the size of this event.”

In their paper in Nature Geoscience the team reports that the jet carries a current of 730 A and is around 75 km long. The researchers also show that gigantic jets do make contact with the upper atmosphere.

“What we were able to conclusively show is that these are not just sparks that come out of the thunderstorm and travel upward and tickle the upper atmosphere,” says Cummer (BBC). “They actually deliver to the upper atmosphere as much electric charge as the very strong lightning strokes to ground.”

Images: Steven Cummer