Space station detector finds source of strange 'blue ray' lightning

Scientists have finally got a clear view of the spark that produces a strange type of lightning called a blue spark.

Blue jets rise from thunderstorm clouds into the stratosphere, reaching altitudes of up to about 50km in less than a second. Whereas ordinary lightning excites a group of gases in the lower layer to glow white, blue lightning excites most of the nitrogen in the stratosphere to give them their characteristic blue color.

Blue lightning has been observed from the ground and aircraft for years, but it's hard to know how they form without rising above the clouds.

Learning about blue jets and other atmospheric phenomena associated with thunderstorms, such as meteors and goblins, is important because these events can affect how radio waves travel. and the atmosphere has the potential to affect communication technology. Penn State space physicist Victor Pasko adds.

In 2019.

The space station's camera and light-sensing instrument, known as a photometer, observed the blue jet during a storm over the Pacific Ocean, near the island of Nauru, in February 2019.

Torsten Neubert, an atmospheric physicist at the Technical University of Denmark in Kongens Lyngby, said: 'The whole thing started with what I think is a 'Blue Blast' - 10 microseconds of brilliant blue light at near the top of the cloud, about 16 km high. From that flash point, a blue jet shot up into the stratosphere, climbing to an altitude of about 52 kilometers in a few hundred milliseconds.

Neubert says the spark that produces the blue light could be a particular form of short-range discharge inside a thunderstorm cloud. Common lightning flashes are formed by electrical discharge between oppositely charged regions of a cloud - or cloud and the ground - many kilometers apart. But highly turbulent mixing in a cloud can create regions of oppositely charged electricity within about a kilometer of each other, creating extremely short but strong currents.

The researchers saw evidence of such short-range, high-energy discharges in radio pulses from thunderstorms detected by ground-based antennas.