When we think of a storm we imagine lightning, thunder, pouring rain. End of story. In reality, much higher than the clouds we see from the surface, the atmosphere stages phenomena that for decades seemed almost like pilot legends: red flashes, blue jets, ultraviolet rings that explode for fractions of a second above storms.
Now those demonstrations have a name, a scientific classification and above all ever clearer images. The astronauts aboard the International Space Station they have in fact captured new photographs of the so-called red spritesspectacular red electrical discharges that form in the upper atmosphere above large storm systems.
Much more happens above the thunderstorms than we see from the ground, and for a few milliseconds the sky lights up red
They look like luminous jellyfish suspended in the sky. They remain visible for just a few milliseconds. And from the ground almost no one can see them.
The red sprites are part of the Transient Luminous Eventsthat is, transient light events that occur above thunderstorms and last very little. They develop in the mesosphere, even at about 80 kilometers altitudewell above the altitude at which normal thunderclouds form. They are triggered by particularly intense electrical discharges in the thunderstorms below and take on that typical reddish color due to the interaction with the nitrogen present in the upper atmosphere.
For years studying them was almost impossible: too fast, too high, too unpredictable. Then came the privileged view of the space.
The ISS has become an orbiting atmospheric observatory and is showing us a side of the sky that almost always escapes from the ground
From the viewing dome of the ISS, astronauts can observe thunderstorms from above, with a perspective that simply doesn’t exist from Earth. And that location has turned into a kind of permanent scientific laboratory.
He has been working on board for years ASIMthe Atmosphere-Space Interactions Monitor of the European Space Agency, an instrument designed specifically to study lightning and electrical phenomena in the upper atmosphere. Alongside this system, the astronauts also use very high-speed cameras as part of the experiment Thor-Daviscapable of recording up to 100,000 frames per second. A speed necessary when the phenomenon you want to observe lasts less than the blink of an eye.
And it is precisely thanks to these technologies that science is starting to better understand what happens above large storms.
These flashes are not just spectacular: they can affect the atmosphere, radio communications and the study of extreme phenomena
The most interesting part is that red sprites are not just a space photography curiosity. Discharges that pass through the upper atmosphere can temporarily alter the ionosphere, the electrically charged region that reflects and transports many radio waves. In practice, such an event can interfere with some long-distance communications and affect sensitive transmission systems.
Scholars are also trying to understand how much these phenomena impact on upper atmospheric chemistrythe formation of other extreme electrical events, and even aviation safety during high-altitude flights near large storm systems.
Not bad for something that seemed like cockpit folklore just a few decades ago.
There is a whole electric world above the clouds that we have only just begun to observe
The red sprites are just part of the show. Thunderstorms also appear above the thunderstorms blue jetsblue jets shooting into the stratosphere, and giant rings of ultraviolet light called ELVESinvisible to the naked eye but detectable by ISS instruments.
All these phenomena tell a fairly simple truth: Earth’s atmosphere is much more dynamic, violent and complex than what we see from below suggests.
For centuries we have watched storms thinking that the sky ended there, at the top of the black clouds.
It was only the ground floor.
