Elves seen from space

Artist impression of lightning in clouds seen from space followed by a blue flash that lasts 10 micro seconds, a blue jet lasting 400 milliseconds and an elve generated by the blue flash that lasts for 30 microseconds. The International Space Station solar panels are shown in the foreground.

Dark clouds, the smell of rain on a hot sidewalk, the flashes of intense light followed by a loud crackling and then a low, rolling thunder – who doesn’t love a good summer thunderstorm. We’ve all seen one, heard one, or been completely soaked by one. But how much do we really know about this weather phenomenon?

As it turns out, there are a lot of things left to discover. Things like blue jets, elves and red sprites. Bizarre-sounding things. Things that are very difficult to observe from the surface of the Earth. As a Nature paper reports, however, the European Atmosphere-Space Interactions Monitor (ASIM) observatory on the International Space Station is helping scientists find answers.

Looking down on Earth’s weather from the International Space Station 400 km above, ASIM’s enhanced perspective is shedding new light on weather phenomena and their characteristics.

The collection of optical cameras, photometers and an X- and gamma-ray detector was installed on the Space Station in 2018. It is designed to look for electrical discharges originating in stormy weather conditions that extend above thunderstorms into the upper atmosphere.

A blue jet is a form of lightning that shoots upwards from thunderstorm clouds. They can reach as far 50 km into the stratosphere and last less than a second. The space storm-hunter measured a blue jet that was kicked off with and intense five 10-microsecond flash in a cloud near the island of Naru in the Pacific Ocean.

The flash also generated equally fantastic-sounding ‘elves’. Elves are rapidly expanding ring of optical and UV emissions at the bottom of the ionosphere. Here, electrons, radio waves and the atmosphere interact to form these emissions. 

Capturing these phenomena using the highly sensitive ASIM tools is vital for scientists researching weather systems on Earth. The observations hold clues to how lightning is initiated in clouds and investigators think these phenomena could even influence the concentration of greenhouse gasses in Earth’s atmosphere, underscoring once more how important it is to find out exactly what’s going on above our heads.