Space Lightning!

~No, this isn't about a new science fiction movie or novel. Space lightning (or "upper-atmosphere lightning") is a very real meteorological phenomenon, and a very impressive one. For many years, observational reports of upper-atmosphere lightning were dismissed, often because airline pilots who observed it were reluctant to speak for fear of ridicule. Not until 1989 were pictures taken by scientists from the University of Minnesota, and its existence was not confirmed until 1994.

^ If you look at the above chart, you'll notice several distinct categories of atmospheric phenomena. Aside from the familiar lightning storm at the bottom, there are also blue jets, sprites, and elves (no, as Dave Barry would say, I Am Not Making This Up). Notice how the "sprites" and "elves" extend well beyond 50 miles (80 km) above sea level, making them technically in outer space (hence "space lightning").

Sprites (named after Ariel from The Tempest) are essentially gigantic sparks caused by powerful lightning discharges in the lower atmosphere; if the discharges are powerful enough, they temporarily increase the strength of the electrical field above the storm, resulting in a sprite. As you can see from the image, it's a huge reddish flash, sometimes nearly 50 miles high, tens of miles across, and potentially occupying thousands of cubic miles.

That may sound impressive, but a sprite is an extremely short-lived event, usually lasting for only 1/100th of a second. Still, that's more than enough for the human eye and brain to perceive them. Don't believe me? See for yourself:



^ This video was recorded by an aircraft flying at ~45,000 feet over a storm in the area of Texas & Arkansas in 1994. It shows the first color images taken of sprites and blue jets.

"Elves", also seen on the chart, are electromagnetic pulse (EMP) shockwaves caused by the electrical discharge that creates sprites. Unlike sprites, however, elves last only ~1/1000th of a second, and are therefore generally too quick for humans to perceive. The term "elves" refers not only to the mysterious, elusive nature of this phenomenon, but is also a mostly-frivolous acronym for "Emissions of Light and Very Low Frequency Perturbations from Electromagnetic Pulse Sources".

Blue jets are not a sports team, but rather cone-shaped blasts of energy that project 25-30 miles from the tops of cumulonimbus (i.e., storm) clouds. Like sprites, the precise cause of blue jets is unknown, but is thought to have less to do with lightning activity and more with intense hail activity in the storms that form them. Blue jets are extremely elusive and very few images have been obtained.




Meteorology discoveries like this remind me of reading the Handbook of Unusual Natural Phenomena (a bit dated, but most of its entries are still very mysterious to modern science). So the next time you're in the middle of a roaring thunderstorm, take a moment to wonder what's going on above the storm. Who knows...perhaps gigantic energy discharges are blasting unfathomable amounts of electricity out into space! I wonder what other mysteries our atmosphere holds for humans to discover and be awed by.