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thegeekgroup, youtube

The Petrified Physical Evidence Of a Lightning Strike

thegeekgroup, youtube
thegeekgroup, youtube

Lightning flashes—while terrifying—appear and vanish in less than a second. Yet, occasionally, passing strikes memorialize themselves with a rocky calling card buried in the earth. Such structures are called fulgurites, also known as “petrified lightning.”

During thunderstorms, the air surrounding a given lightning bolt can get incredibly hot—temperatures exceeding 50,000⁰ Fahrenheit (27760⁰ Celsius) have been recorded. To understand just how scalding that is, note that the surface of our sun only reaches about 10,000⁰ F (5500⁰ C). Naturally, this doesn’t bode well for lightning-strike victims, who often receive severe third-degree burns.

If, instead of a person, lightning hits a sandy beach, an amazing geological phenomenon can take place. Jolted by the sudden, intense heat, unsuspecting sand or rock particles may melt down and re-fuse almost instantly. Thus, a baby fulgurite is born.

These elongated tubes have been found all over the world, from the Sahara desert to the California coastline. Hollow and made of natural glass, fulgurites can reach over 13 feet in length, though a young Charles Darwin once wrote that 30-foot specimens had been reported in England during the 19th century. 

Unfortunately, these glassy objects aren’t noted for their resiliency. Petrified lightning samples tend to get shattered by the elements in short order, making quality samples scarce. However, some passionate tinkerers have created their very own artificial fulgurites with some electrical gear and a few buckets of sand. Check out this awesome video to see how it’s done:

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History
The Queen of Code: Remembering Grace Hopper
By Lynn Gilbert, CC BY-SA 4.0, Wikimedia Commons

Grace Hopper was a computing pioneer. She coined the term "computer bug" after finding a moth stuck inside Harvard's Mark II computer in 1947 (which in turn led to the term "debug," meaning solving problems in computer code). She did the foundational work that led to the COBOL programming language, used in mission-critical computing systems for decades (including today). She worked in World War II using very early computers to help end the war. When she retired from the U.S. Navy at age 79, she was the oldest active-duty commissioned officer in the service. Hopper, who was born on this day in 1906, is a hero of computing and a brilliant role model, but not many people know her story.

In this short documentary from FiveThirtyEight, directed by Gillian Jacobs, we learned about Grace Hopper from several biographers, archival photographs, and footage of her speaking in her later years. If you've never heard of Grace Hopper, or you're even vaguely interested in the history of computing or women in computing, this is a must-watch:

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science
Why Are Glaciers Blue?
iStock
iStock

The bright azure blue sported by many glaciers is one of nature's most stunning hues. But how does it happen, when the snow we see is usually white? As Joe Hanson of It's Okay to Be Smart explains in the video below, the snow and ice we see mostly looks white, cloudy, or clear because all of the visible light striking its surface is reflected back to us. But glaciers have a totally different structure—their many layers of tightly compressed snow means light has to travel much further, and is scattered many times throughout the depths. As the light bounces around, the light at the red and yellow end of the spectrum gets absorbed thanks to the vibrations of the water molecules inside the ice, leaving only blue and green light behind. For the details of exactly why that happens, check out Hanson's trip to Alaska's beautiful (and endangered) Mendenhall Glacier below.

[h/t The Kid Should See This]

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