On May 14, 2018, a storm rained straight out of the Twilight Zone over Oklahoma.
Rather than scattering the Earth with jagged bolts of lightning, the veils of dense clouds fueling this storm spew a 50-mile upwards, far enough to brush the ionosphere or the edge of space. This violent, backward-directed surge of electricity would soon be classified as one of nature’s most mysterious atmospheric phenomena: a gigantic jet.
Giant jets are simply glowing jets that form alongside normal lightning, but point in the opposite direction. But they are much stronger than their downward-facing counterparts, sometimes even threatening spacecraft or other technology floating in our planet’s orbit. And this particular one was incredibly intense. Considered the most powerful of its kind studied to date, it carries an estimated 300 coulombs of electrical charge, a whopping 100 times more than typical lightning bolts hold.
Over the past two decades, scientists have identified several of these strange forces, but many of these sightings have been accidental catches of the public.
For example, a purple streak was photographed by an airplane flying over Bhadrak in India, and another was spotted with a night camera near the 6,240-foot summit of Mount Shikengkong in China. In 2013, NASA added an experiment to the ISS to get a better, more actively placed view of the scene above cloud cover so we could see giant jets in action. Still, the scientific community doesn’t have many observing systems tailored to the search.
For that reason, the Oklahoma incident in 2018 was a happy accident.
Coincidentally, this extreme event happened near a number of relevant scientific instruments in the state, such as satellite networks and a lightning mapping system that detects so-called “very high-frequency signals.” A citizen scientist in the area even photographed it with a low-light camera. Based on all of these clues, a group of scientists gathered as much data as possible about the jet to try to paint a detailed retelling of what happened in Oklahoman’s swirling skies four years ago.
This gigantic jet was captured with a single 3.2 second exposure over Bhadrak, India. Though the giant jet appears to be attached to the plane’s wing, it likely began in a more distant thunderhead and can be seen extending upward toward Earth’s ionosphere.
Hung-Hsi Chang/NASA
“We were able to map this gigantic jet in three dimensions with really high-quality data,” said Levi Boggs, a researcher at Georgia Tech Research Institute and author of an article on the structure published Aug. 3 in the journal Science Advances, “says it in a press release.
Such a three-dimensional structure is important in the quest to decode gigantic jets, as their ascent from clouds means they are often not visible. “We were able to see very high-frequency sources above the cloud cover that had not previously been seen with this level of detail,” Boggs said. And those VHF signals offered a gold mine of information about giant jets.
Basically, lightning emanating from thunderclouds is created by a combination of leaders and streamers. Leaders are the result of electrical charge differences that contribute to the development of lightning, and streamers are at the very top of these developing lightning. Together these forces work to spread the electricity channeled from the storm cloud, but the leaders usually make up the bulk of the discharge.
The researchers of the new study initially saw clearly that the gigantic nozzle-producing leaders and streamers were located Above the storm cloud during the Oklahoma event, rather than lower down where they would normally be found. Second, “the radio and optical data provide the first clear evidence that the VHF observed by lightning networks is generated by streamers ahead of the leader,” the study authors wrote.
“These cold streamers start spreading just above the cloud cover,” Boggs explained. “They spread into the lower ionosphere to an altitude of 50 to 60 miles and make a direct electrical connection between the cloud cover and the lower ionosphere.”
In addition, the team analyzed many other interesting charge dynamics of giant jets and even settled on a possible explanation for why these strange jets are spurting out in the first place. “For whatever reason, there’s usually suppression of cloud-to-surface discharges,” Boggs said of records collected from the Oklahoma event. “In the absence of the lightning discharges we normally see, the gigantic jet could reduce the build-up of excess negative charge in the cloud.”
In other words, some storm clouds might be bottling their negative energy – and as they say, that will come out one way or another.
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