Rare Blue ‘Luminous Event’ Photographed From the ISS

Astronaut Thomas Pesquet has photographed a rare blue “transient luminous event” over Europe that was captured as part of a timelapse he shot from on board the International Space Station (ISS).

Thomas Gautier Pesquet, a French aerospace engineer who took part in the European Space Agency’s Expedition 50 and 51 and was assigned to the SpaceX Crew-2 mission, regularly shares a fascinating insight into space exploration.

He invited his audience to learn more about space by sharing photographs and timelapses throughout his time on the ISS. His latest observation, taken from a longer timelapse, shows a bright blue “light bomb” exploding over Europe.

Although it may appear ominous, the light didn’t do any damage. This natural phenomenon is known as upper-atmospheric lightning, which occurs during thunderstorms and is observed above where normal lighting would appear.

Science Alert explains the phenomenon as “blue jets” which happen lower down in the stratosphere and are triggered by lightning.

“If the lighting propagates through the negatively charged (top) region of the thunderstorm clouds before it gets through the positive region below, the lightning ends up striking upwards, igniting a blue glow from molecular nitrogen,” the publication explains.

These are not the only transient luminous events that can be observed. Others include electrical discharges that often have a red glow, slightly dimmer red ones that occur in the ionosphere, and others.

Under the timelapse frame, shared on Flickr, Pesquet explains that “what is fascinating about this lightning is that just a few decades ago they had been observed anecdotally by pilots, and scientists were not convinced they actually existed.”

Although Pesquet doesn’t confirm which specific type of luminous event is visible in the frame, Science Alert speculates it could be a “blue starter,” which is a blue jet that doesn’t quite make it to the jet part and instead creates a shorter and brighter glow.

What makes Pesquet’s photo unique is that these events are particularly hard to photograph from the ground because they occur so high in the sky, are often obscured by storm clouds, and only last for a couple of seconds or less each time.

“The Space Station is extremely well suited for this observatory as it flies over the equator where there are more thunderstorms,” says Pesquet. “This is a very rare occurrence and we have a facility outside Europe’s Columbus laboratory dedicated to observing these flashes of light.”

This isn’t the first time Pesquet has captured a rare blue atmospheric occurrence, either. In September, he shared a series of images where he captured the Aurora Australis giving off a rarely-seen blue hue that only happens under very precise geomagnetic conditions.

Pesquet regularly shares photos and videos from the orbiting space station on his Twitter and Flickr.

Image credits:  Photo by Thomas Pesquet, ESA