Mostly Mute Monday: Volcanic Lightning

Lightning: it isn’t just for stormclouds.

“If you are caught on a golf course during a storm and are afraid of lightning, hold up a 1-iron. Not even God can hit a 1-iron.” –Lee Trevino

Image credit: Martin Rietze(Alien Landscapes on Planet Earth).

Image credit: Ragnar Th Sigurdsson / www.arctic-images.com.

Image credit: Francisco Negroni / Associated Press, Agenci Uno / European Press Photo Agency.

Image credit: Nordicphotos / Getty Images Contributor.

Image credit: volcanic lightning in Kyushu, Japan, via http://i.imgur.com/dLAjD36.jpg.

Image credit: Terje Sorgjerd/Getty Images.

Image credit: Sigurdur Hrafn Stefnisson / National Geographic.

When the voltage between two distant points exceed the breakdown voltage of air, a lightning strike occurs. During thunderstorms, approximately ten Coulombs of charge — some 10^20 electrons — are exchanged with every bolt, representing the release of an incredible build-up of energy.

During a volcanic eruption, however, the incredible heats cause neutral atoms to become ions, either positively or negatively charged, which then separate due to differences in masses, temperatures and physical cross-sections. The aerodynamics separates the particles even farther, and when the threshold of breakdown voltage is crossed, a lightning strike occurs. The photos below, most spectacularly, show multiple lightning strikes observed over the span of many minutes, taken as a time-lapse. All told, volcanic lightning has been observed and well-documented in over 150 eruptions, from the recent ones Eyjafjallajökull (in Iceland), Puyehue-Cordón Caulle (in Chile) and Sakurajima (in Japan) all the way back to the infamous eruption of Mt. Vesuvius nearly 2000 years ago!

Mostly Mute Monday tells the story — in images with 200 words max — of a particular physical or astronomical sight found in this Universe. For more about volcanic lightning and its causes, have a read here.

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