Have you ever seen a giant red jellyfish light up the night sky for a split second? If you have, you're not imagining things.

You've just witnessed a lightning-like electrical discharge high in the atmosphere known as a sprite.

Paul Smith captured the elusive phenomenon Wednesday night as storms raged over northwest Oklahoma and the Panhandle. Smith positioned himself 100 miles (about 160 kilometres) southeast of the storms in the town of Anadarko, a small community west of Oklahoma City with a population of just under 7,000.

Ordinarily, that's too far away to take pictures of lightning strikes – unless you're looking for flashes of heat lightning to illuminate distant thunderheads. But Smith didn't have his camera trained on the storms – he was looking above them.

That's where sprites live. They aren't born within the clouds. They distribute charges well above them about 30 to 50 miles (48 to 80 kilometres) up in the sky.

Commercial jetliners fly at a height of six to seven miles altitude. Sprites dance in the mesosphere – higher than where shooting stars and meteors burn up.

And although it's difficult to tell from photos, sprites are very large. An ordinary lightning bolt is about an inch thick and several miles (about 5 kilometres) long.

Jellyfish sprites can be 30 miles (48 kilometres) across. Imagine one electrical discharge spanning the distance from Baltimore to Washington, D.C. Other sprites can be a bit smaller, such as column sprites and carrot sprites.

The photos Smith took appear to be of the jellyfish variety. Later that evening, he also caught some column sprites.

"I captured a number of sprites during 2018," Smith said in an email, "but this last outing has been one of my favorites. It was very challenging with an almost full moon at my back."

Although sprites are poorly understood, atmospheric electrodynamicists have figured out the basics behind their formation.

Sprites are often triggered by a strong, positive bolt of ordinary lightning near the ground. They're thought to be a balancing mechanism that the atmosphere uses to dispense charges vertically. It's a quick process that takes less than a tenth of a second. That's what makes hunting for sprites so tough. Blink and you'll miss them.

Sprites weren't known about until 1989. For decades, pilots had reported seeing enormous fleeting bursts of light above storm tops, akin to strobing pink fireworks.

But it wasn't until an auroral physicist at the University of Minnesota snapped a photo of one that scientists were able to confirm their existence. The physicist, John R. Winckler, had been testing a low-light television camera that would be used to document an upcoming rocket launch, and he photographed the sprite accidentally.

Nowadays, pictures of sprites are routinely captured worldwide. With the right set of conditions, you could even try it from your backyard!

Sprites aren't terribly rare – they're just elusive. You need an unobstructed view of a distant, sparky thunderstorm. It needs to be dark enough that your camera won't be overexposed by taking long exposures. There can't be much light pollution, as that would wash out an attempt to snag a sprite. And of course, you need strong storms. So the best odds of catching a sprite are over the Great Plains during spring.

Sprites feed off strong electrical disturbances near the surface. So the more frequent and intense the lightning at ground level, the better the odds of seeing a sprite. That's why big, sprawling clusters or squalls of thunderstorms are more favorable instigators of sprite activity than isolated storm cells.

June is the peak month for these sorts of storms, as large mesoscale convective systems blast through the central and high Plains. These complexes can put down 100,000 or more lightning bolts every night, shedding sprites by the dozen up above – if you know where to look.

So next time you're enjoying a cool evening beverage watching faraway storms rage, look up. You may get to see something incredible. Smith sure did.

"I got my first sprite in 2017," he said, "and have been obsessed ever since."

2019 © The Washington Post

This article was originally published by The Washington Post.