thunderstorm filmed from onboard the International Space Station
© Geophysical Research Letters
Rare footage of a thunderstorm filmed from onboard the International Space Station (ISS) has raised more questions than answers for scientists, according to a new study.

Described as a first of its kind, footage of "elusive blue jets" was filmed in 2015 over the Bay of Bengal by European Space Agency astronauts using the most sensitive camera on the space station.

Gigantic electrical discharges and jets can be seen in the footage with numerous flashes visible within the storm clouds. A number of blue-purple discharges are followed by a "pulsating blue jet" shooting up out of the cloud.

"The blue discharges and jets are examples of a little-understood part of our atmosphere," the ESA said in a statement. "Electrical storms reach into the stratosphere and have implications for how our atmosphere protects us from radiation."

These "astonishing" jets reach up to 40km (25 miles) in height before fading, according to the study, which was published by Denmark's National Space Institute as part of an experiment known as THOR.

Blue jets can move at speeds of up to 360,000kph (220,000mph) and without a high speed camera they can be easily missed by the human eye.
Blue jets filmed from ISS
© Geophysical Research Letters

Similar studies will be taking place later this year with the Atmosphere - Space Interactions Monitor launching with the aim of monitoring such "transient luminous events" on an ongoing basis.

ESA astronaut Andreas Mogensen, who captured the footage, said: "It is not every day that you get to capture a new weather phenomenon on film, so I am very pleased with the result - but even more so that researchers will be able to investigate these intriguing thunderstorms in more detail soon."