High above storm clouds and far beyond the reach of commercial aircraft, scientists are studying elusive electrical discharges known as transient luminous events TLEs . These short-lived phenomena include red sprites, blue jets and ELVES: bursts of light triggered by lightning that occur tens of kilometres above active thunderstorms.
For decades, pilots reported unexplained flashes in the upper atmosphere. Researchers later confirmed these sightings and coined names for the different forms they observed. Today, those reports are being matched with hard data thanks to the AtmosphereSpace Interactions Monitor ASIM , which has been operating aboard the International Space Station since 2018.
Developed by Danish aerospace firm Terma and operated from a control centre in Belgium, ASIM was designed to detect visible light, ultraviolet radiation and X-rays produced by rare electrical activity between 20 and 100 kilometres above Earths surface. Mounted externally on the station, it has a clear view of large thunderstorm systems, particularly over equatorial regions where lightning activity is most intense.
