New research finds cosmic rays hitting the atmosphere cause of the ignition of lightning

Two lightning flashes graphed
Click for original image.

New research has now found that the shower of energy produced when a cosmic ray hits the atmosphere could be a major cause for the ignition of lightning in thunderheads.

You can read the paper here. The two graphs to the right are taken from figure 3 of the paper, and show two different lightning events. The colors represent time, going from green (earliest) to blue to yellow and red (latest). The white dot marks the spot where the lightning flash started. From the article above:

We believe that that most lightning flashes in thunderstorms are ignited by cosmic ray showers,” says the study’s lead author Xuan-Min Shao, a senior scientist at the Los Alamos National Laboratory in New Mexico.

…One of the important things about cosmic ray showers is that they contain antimatter–positrons as well as ordinary electrons. The Los Alamos 3D lightning maps contained strong evidence for positrons. Electrons and positrons are bent in opposite directions by Earth’s magnetic field, so they leave opposite imprints on the lightning’s polarization, which BIMAP-3D also measured.

…Positrons clinched the case for cosmic rays. “The fact that a cosmic ray shower provides an ionized path in the cloud that otherwise lacks free electrons strongly favor the inference that most lightning flashes are ignited by cosmic rays,” the authors wrote.

It remains unclear if cosmic rays cause all lightning flashes or just some. Either way, it is a remarkable thing to consider: Cosmic rays are created in distant interstellar and even intergalactic events. The rays take millions, maybe billions of years to reach Earth. And when they do, they produce lightning in thunderstorms!

Hat tip reader Steve Golson.

Instrument designed to detect lightning releases first data

Lightning over Europe
Lightning over Europe. Click for original movie.

The first data from the Lightning Imager launched in December 2022 on Europe’s Meteosat weather satellite has now been released, the images compiled into movies showing lightning activity across Europe, Africa, the Middle East and parts of South America.

While the animations are a first initial result from the Lightning Imager, the Meteosat Third Generation Imager is currently undergoing its commissioning phase during which the instruments are calibrated and the data is validated. Data from the Lightning Imager will be available for operational use in early-2024 at an increased sensitivity.

You can see all the movies here. The lightning is found almost exclusively over land. In fact, you can see the lightning in one storm vanish as the storm drifts out into the Mediterranean.