Even cooler, the glass spherules created by lightning strikes when they hit volcanic ash form high in the atmosphere

Mar 4, 2015 08:15 GMT  ·  By

It is a well-known fact that, when hitting rocks and sediments, lightning strikes can cause the natural materials that comprise them to melt and, in doing so, birth all sorts of glassy structures.

In a new paper, scientists with the Geological Society of America argue that the same thing can happen to volcanic ash. That's right, it appears that volcanic ash can too turn into glass if hit by a lighting strike.

Even cooler, the glass spherules that come into being during such close encounters form high in the atmosphere. Just moments after creation, gravity grabs hold of them and they fall to the ground.

How lightning strikes work

Clouds generate lightning strikes because of the movement of the water droplets and the ice fragments that comprise them. This commotion gives clouds a positive charge at the top and a negative one at the bottom, thus causing electrical discharges.

Once produced, these electrical discharges that we call lightning strikes leave their parent cloud and move towards the ground or sometimes even upwards at mind-boggling speeds.

While on this journey, they heat the air around them at about 30,000 degrees Celsius (54,000 degrees Fahrenheit). This temperature is roughly 5 times greater than the one documented on the surface of the Sun.

Given how much heat they generate, it is no wonder that lightning strikes can melt rock and sediments and, as confirmed by the Geological Society of America researchers in a series of lab experiments, even melt volcanic ash and turn it into tiny glass spheres.

The glass spheres are all unique

In a report in the journal Geology, specialist Kimberly Genareau and fellow researchers explain that such spheres of glass created by lightning strikes have over the years been discovered all across the world in the proximity of active volcanoes.

For instance, quite a lot of them were recovered from the ground following the March 2009 eruption of Mount Redoubt in Alaska and after the April May 2010 eruption of Eyjafjallajökull, an active volcano located in Iceland.

The specialists say that, while some of these spheres have a surprisingly smooth surface, others display all sorts of holes or sometimes even cracks. It is believed that these deformations are the result of the outward expansion of the sphere's interior under the influence of heat.

Photo shows a miniature glass sphere obtained in the lab
Photo shows a miniature glass sphere obtained in the lab

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Lightning strikes can turn volcanic ash into glass, study finds
Photo shows a miniature glass sphere obtained in the lab
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