Fulgurite: when lightning strikes the sand
In the rare cases when an electric bolt of lightning strikes the sand or soil, the sudden heat causes the sand to sinter into full glass tubes of unusual shape. This formation is called fulgurite, and in the people — "devil's finger". And in fact, sometimes they look like completely foreign structures that have come to Earth either from Hell or from the depths of space:
— Dan Skoff (@weatherdan) February 17, 2014
According to experts, the world is full of fulgurites. "All you need to do is go to any beach and start digging," says Martin Uman of the University of Florida. However, due to their popularity on the web, you can often see ads for the purchase of fulgurites, which were actually made artistically:
Fulgurite is the product of sand being struck by lightning pic.twitter.com/wju6i5e9KQ
— Reg Saddler (@zaibatsu) October 13, 2018
This is especially important when it comes to real science. By studying how and with what force lightning strikes the ground in a particular region, climatologists can assess the potential damage to underground power lines and come up with ways to avoid such accidents. Sometimes, for a spectacular shot, photographers dig out fulgurites from the sand so that they look as spectacular as possible in the frame:
See this thing?
It's a fulgurite, and it's formed when goddamn LIGHTNING hits sand or soil, and the heat from the strike (>27,000°C!) fuses the silica to glass.
Geology rocks. pic.twitter.com/aVqSPRxghR
— Paul Byrne (@ThePlanetaryGuy) April 28, 2020
Note that although across the globe lightning strikes the earth, trees, and buildings at least a million times a day, only a small part of them has enough power to turn sand into glass. So in practice, they are quite rare. In the 1990s, researchers searching for "damn fingers" accidentally discovered the absolute record holder: the length of this "petrified lightning" was more than 4.9 meters!