Could Lightning Come From Space?

Cosmic rays may cause a “runaway breakdown” of electrons when they collide with highly charged particles in thunderclouds

S-Ky photography

You would think that we’d know how thunder and lightning work by now. But researchers still puzzle over what, exactly, causes those bright flashes of electrostatic discharge. Lightning electrifies the sky about 100 times per second in various locations around the world, yet the electric fields within thunderclouds seem to have only about a tenth of the strength required for producing a lightning bolt, LiveScience reports.

As it turns out, lightning may have extraterrestrial origins. This idea is not new:

More than 20 years ago, physicist Alex Gurevich at the Russian Academy of Sciences in Moscow suggested lightning might be initiated by cosmic rays from outer space. These particles strike Earth with gargantuan amounts of energy surpassing anything the most powerful atom smashers on the planet are capable of.

Cosmic rays slamming into air molecules may split those molecules into many electrons, which collide in turn with additional molecules, snowballing into more and more electrons zipping around. Gurevich called this “a runaway breakdown,” LiveScience writes.

In a new paper, Gurevich and colleagues analyzed radio pulses from around 3,800 lightning strikes. They hypothesize that thunderclouds’ highly electrically charged water droplets and ice nuggets allow even the most un-energetic cosmic rays to spark a bolt of lightning if it comes into contact with such a cloud. Researchers know that cosmic rays hit the planet about as frequently as lightning strikes, LiveScience writes, so the theory at least makes sense.

Unfortunately, Gurevich and a number of other scientific groups are still in the process of taking simultaneous measurements of cosmic ray’s energetic particles and the radio pulses lightning produces, which should help determine whether or not the two phenomenon are indeed linked. At least for now, Gurevich’s idea—long ignored by science—is at least being given the attention needed to prove once and for all whether lightning does have extraterrestrial origins.

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