Blue 'jets' of lightning shooting upwards from thunderclouds have been detected by an instrument on board the International Space Station, a study has reported.

It reached up into the stratosphere — experts believe that blue jets can span distances of up to 31 miles (50 km) — and lasted less than a second.

Because blue jets form above the cloud layer, they are very difficult to see — and study — from down on the surface of the Earth.

Orbiting some 249 miles (400 kilometres) about the clouds, however, the International Space Station is afforded a non-obstructed view.

Understanding the formation of blue jets — and other energetic phenomena in the stratosphere and above  — can reveal clues about how lightning is triggered.

Blue 'jets' of lightning shooting upwards from thunderclouds have been detected by an instrument on board the International Space Station, a study has reported.

Understanding the formation of blue jets — and other energetic phenomena in the stratosphere and above, as pictured — can reveal clues about how lightning is triggered.

Measured by the European Space Agency's Atmosphere-Space Interactions Monitor (pictured), the phenomenon originated in a cloud top over the Pacific island of Nauru.