Of all the weather onions that our beautiful planet throws at us, lightning is one of the most amazing – and most mysterious – things. Even though storms occur on a regular basis, we are still at a difficult stage to understand and account for the brutal electric transmission created in the skies.
One type of lightning is so strange and rare, in fact, that we didn’t even have concrete evidence that existed until 1990, when researchers identified the signature ‘rocket-like’ movement in a video from NASA’s Space Shuttle previous year.
Later called ‘blue jets’, the streaks are now known as bright flashes of light that last just a few hundred thousand miles, as lightning flows up from the clouds and into the stratosphere.
Photograph of a blue pier in Hawai’i. (Gemini Theater / AURA / Wikimedia Commons)
We can’t see this phenomenon below a cloud curtain – but that doesn’t mean scientists can’t see it from above. About 400 kilometers (250 miles) above the planet orbit the International Space Station, and for some time, instruments on board have been on the lookout for those mysterious showers of lightning upside down.
Now, after its launch in 2018, the European Space Station’s observatory is equipped with optical sensors, photometers, and detectors for gamma and X-radiation that have recorded five blue flashes from the top of a storm cloud, one of which ended with a blue jet climbing. high into the stratosphere.
These rare sightings give us a valuable insight into the beginning of the secret release, according to a team of physicists led by physicist Torsten Neubert from the Technical University of Denmark.
Blue jets are expected to start when a well-charged cloud roof meets a cover of negative charge at the end of the clouds and the air level above. This is thought to cause a conductor-induced electrical outage – an invisible conduction channel of ionized air on which the lightning travels.
However, our understanding of the blue jet leader is very limited. This is where the data analyzed by Neubert and his team fill in gaps.
On February 26, 2019, the Atmosphere-Space Interactions Monitor (ASIM) observatory recorded five blue flashes, approximately 10 microseconds long each, in a storm surge peak, near the Pacific island of Nauru.
One of these flashes gave a blue jet, reaching as far as the stratopause – the interface between the stratosphere and the ionosphere, at an altitude of about 50 to 55 kilometers (about 30 to 34 miles).
In addition, the observatory recorded atmospheric pulses called ELVES (short for light emissions and very low frequency wavelengths due to Electromagnetic Pulse sources). These extend rings of optical and ultraviolet emissions in the ionosphere that emerge above storm clouds, lasting just a million miles or so, as seen in the animation below.
They are thought to have been generated by an electromagnetic shock at the base of the ionosphere, caused by lightning transmission.
But red emissions from the leader were weak and very limited. This, the research team said, suggests that the conductor itself is very short and local, as opposed to fully developed lightning conductors between the ground and the clouds.
This also suggests that the flares and the blue jet itself are a kind of scattering climber: branching, readily emitting sparks emanating from high-voltage sources, such as Tesla corals, on a chain reaction of grains air ionizing.
“We then suggest that the UV rays generated by the flash streamer currents, rather than lightning strikes, are elves,” the researchers write in their paper.
The flavors, they believe, are similar to narrow bipolar events. These are high-powered radioactive transmissions that occur inside clouds during hurricanes, which are known to stimulate lightning inside the cloud. The blue flashes in the tops of the clouds, the team said, tend to be optically equivalent to this phenomenon, and can be blue jets.
Since narrow bipolar events are very common, this may mean that the blue flashes are more common than we thought. Finding out more about their prevalence could lead to a better understanding of storms and lightning, not to mention our atmosphere, and all their complex interactions. .
The team ‘s research was published in Nature.