A rare red sprite – a transient luminous event – photographed by astronauts from the International Space Station above a powerful storm.
Credit : NASA/Nichole Ayers
Astronauts aboard the International Space Station have captured astonishing images of strange lightning storms happening far above Earth’s clouds, and the photos released by NASA are revealing a hidden side of our planet’s atmosphere that few people have ever seen. The brief flashes – glowing red, blue and violet – appear high above thunderstorms and last only milliseconds, but from orbit they look like surreal fireworks lighting up the edge of space.
The phenomena, known as transient luminous events (TLEs), occur so high above Earth that they are almost impossible to observe from the ground. But thanks to specialised cameras on the International Space Station (ISS), scientists are finally getting a clear look at these mysterious flashes and trying to understand what they might mean for weather, aviation and even radio communications.
The strange lightning storms most people never see
Most of us only experience thunderstorms from below – a crack of thunder and a flash of lightning across the sky. But above those clouds, something even stranger can happen.
Scientists have identified several types of electrical events that occur up to about 55 miles (around 90 kilometres) above Earth’s surface. Among them are:
- Red sprites, glowing structures that appear above thunderstorms for just a few milliseconds
- Blue jets, which shoot upward from storm clouds toward the stratosphere
- Halos and ultraviolet rings, sometimes called ELVES, which expand rapidly in the upper atmosphere
These flashes are incredibly fast and faint, which is why they were long considered almost mythical. For decades, they appeared mainly in pilot reports or occasional photographs taken by chance.
Now, however, the ISS has changed the game. From its orbit roughly 400 kilometres above Earth, astronauts and instruments can watch storms from above, where these strange bursts of light become far easier to detect.
A powerful storm-watching instrument on the ISS
One of the main tools responsible for these discoveries is the Atmosphere–Space Interactions Monitor (ASIM), a European Space Agency instrument attached to the outside of the space station since 2018.
ASIM was built specifically to observe lightning and other electrical events from space. Its high-speed cameras and sensors are sensitive enough to detect flashes smaller than a fingernail and lasting only a fraction of a second.
The instrument has already captured thousands of events, helping scientists understand how energy from thunderstorms can travel upward into the ionosphere, a charged region of the atmosphere important for radio communications.
One phenomenon that fascinates researchers is the formation of ELVES rings, enormous expanding circles of ultraviolet light triggered by powerful lightning strikes. These rings can spread across hundreds of kilometres almost instantly, potentially affecting the electrical balance of the upper atmosphere.
Astronauts filming storms from space
The technology on the ISS doesn’t stop with automated instruments.
Astronauts themselves are also helping capture these rare events. Inside the station is the Cupola, the famous observation dome with seven large windows that provide a panoramic view of Earth.
Using a special high-speed camera system as part of the Thor-Davis experiment, astronauts can record distant storms at up to 100,000 frames per second. When scientists slow down the footage, they can study lightning’s branching patterns and electrical structures in extraordinary detail.
These images are more than just beautiful – they help scientists compare real storms with laboratory experiments on plasma and electricity.
Understanding lightning in such detail could eventually help improve systems designed to protect power grids and aircraft from severe electrical storms.
Invisible bursts of radiation also detected
Some storms produce another surprising effect: terrestrial gamma-ray flashes, bursts of radiation that occur during lightning events.
These flashes are extremely brief, but they can be powerful enough to expose aircraft passing through a storm to a short burst of radiation comparable to a medical X-ray.
To study these events, researchers have deployed a small satellite called Light-1 from the International Space Station. The cube-shaped satellite carries specialised detectors that track high-energy radiation produced during storms.
By comparing the satellite’s measurements with ground-based lightning networks, scientists hope to build a detailed map showing where these gamma-ray flashes occur most often.
Why these discoveries matter
At first glance, glowing sprites and blue jets might seem like little more than spectacular natural light shows. But researchers believe these phenomena could have important implications for technology and climate science.
Because they occur in the same atmospheric region used to transmit radio signals, these flashes may occasionally disturb communications or navigation systems.
Scientists also suspect they play a role in the movement of certain chemicals between atmospheric layers, potentially affecting ozone and climate processes.
With the International Space Station expected to keep operating for several more years, scientists say they will continue collecting data on these mysterious events.
Each new image captured from orbit adds another piece to the puzzle of how thunderstorms interact with the edge of space – a hidden world of lightning that most people on Earth will never see.
