Lead image credit: Thomas Pesquet / ESA

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French astronaut Thomas Pesquet is currently aboard the International Space Station (ISS). The view from about 400km (250 mi) affords Pesquet and other astronauts a stunning view of space and Earth. Pesquet also gets to witness interesting atmospheric phenomena, including a recent rare blue 'transient luminous event' over Europe.

While photographing a timelapse, Pesquet captured a single frame showing upper-atmospheric lightning. Science Alert wrote about Pesquet's image and described the event as a 'lightning-like phenomenon striking upwards in the upper atmosphere.'

While related to lightning, the blue glow Pesquet observed occurs above where typical lightning is observed and operates slightly differently. The 'blue jets' like Pesquet observed are triggered by lightning. Lightning can strike upward if the lightning travels through the upper region of thunderstorm clouds, which are negatively charged before traveling through the positively charged region below. This upward strike creates a blue glow as it ignites molecular nitrogen.

Since it's challenging to observe this phenomenon from the surface of the Earth and evidence was largely anecdotal from pilots, scientists were not sure that this type of transient luminous event existed. As Pesquet writes on his Flickr, 'Fast forward a few years, and we can confirm elves, and sprites are very real and could be influencing our climate too! My friend Andreas Mogensen has a large part to play in this story, he was the first to capture them from space (in only ten days on the Space Station he did all this, legend!) proving the worth of having a facility to monitor the flashes!'

The event can last mere milliseconds or up to a couple of seconds, so it's challenging to photograph a transient luminous event unless you're shooting timelapse images like Pesquet. In addition to blue jets and glows, there are also occasionally red electrical discharges. The various phenomena have great names, like SPRITES (Stratospheric/mesospheric Perturbations Resulting from Intense Thunderstorm Electrification), ELVES (Emission of Light and Very Low Frequently perturbations due to Electromagnetic Pulse Sources), TROLLs (Transient Red Optical Luminous Lineaments), Pixies, Ghosts (Green emissions from excited Oxygen in Sprite Tops) and Gnomes.

Pesquet's name may sound familiar to regular readers. In June, Pesquet shared an image that illustrates how quickly the ISS orbits Earth. In September, we wrote about Pesquet's photos of a rare blue auroral event. The aerospace engineer has observed a lot of unusual activity during his time aboard the ISS.