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Barcroft TV, Youtube

The Science Behind Super Rare (and Totally Amazing) Volcanic Lightning

Barcroft TV, Youtube
Barcroft TV, Youtube

Recently, a viral video of rare volcanic lightning footage has been making the rounds on social media. It’s easy to see why. The dramatic clip appears to show flecks of lightning dancing though an ominous volcanic plume, the likes of which most viewers have never seen. Make that all viewers, actually: As it turns out, the clip was actually doctored by the BBC, which combined footage from two separate eruptions for a scene in their hit series Patagonia: Earth’s Secret Paradise.

Nonetheless, volcanic lightning—a phenomenon that’s also known as a “dirty thunderstorm”—is still very real. Here’s what the incredible display actually looks like:

Back in March, German photographer Marc Szeglat captured the spectacle above, which is the Sakurajima volcano, located on Kyushu, Japan’s third-largest island. (Before 1914, the volcano sat on a smaller island named Sakurajima, but a huge eruption that year merged the landmass with Kyushu proper.)

A seasoned volcano photographer, Szeglat set out to document a Sakurajima blast and, in the process, also captured one of nature’s most mysterious wonders. At 2:05 in the video, you can see a lightning bolt zig-zagging across the eruption’s ashy mushroom cloud. 

What’s going on here? Believe it or not, some volcano-generated plumes are capable of creating powerful electrical charges that can lead to streaks of lightning, and bolts as large as two miles long.

As Szeglat explained to the BBC, “In a normal thunderstorm ice crystals collide and generate electrical charges, which results in lightning. In an eruption cloud, ash particles collide instead of ice crystals.”

But how do these particle collisions actually produce lightning? Experts aren’t entirely sure. “How lightning forms in general is still debated among scientists,” writes geologist Brentwood Higman on Geology.com, “and volcanic lightning is even less well understood.”

Still, we can say with reasonable certainty that all dirty thunderstorms require what’s known as a pyroclastic flow—fast-moving volcanic currents consisting of hot gas, rock fragments, and ash.  They’re also incredibly dangerous, as the billowing clouds tend to “hug” the ground and bury everything in their path. Such flows famously descended upon Pompeii in 79 CE, while others surged forth from Mount St. Helens during its sky-darkening 1980 eruption

As tiny particles are kicked into the atmosphere, they begin to move apart or split in two. The positively charged particles separate from their negatively charged brethren, and eventually build up enough attraction to cause a serious spark. According to Higman, “Lightning is the electrical flow that results when this charge separation becomes too great for air to resist the flow of electricity.”

Well-documented dirty thunderstorms broke out at Mount Redoubt of Alaska in 2009 and Iceland’s Eyjafjallajökull in 2010. Masses of round, glassy beads were later discovered at both sites, and earlier this year, an international scientific team concluded that the spherules had been forged by volcanic lightning. In theory, the incredibly hot bolts (whose scalding temperatures can reach 30,000°C) melted down pieces of ash which then re-solidified as little glass balls. 

Recent research also suggests that volcanic lightning bolts come in at least two distinct types. Some—like these—dart about near the tops of plumes. Meanwhile, others simply hang around the volcano’s mouth.

Volcanic lightning storms can also demonstrate the kind of intensity that’s normally reserved for Midwestern tempests. Unfortunately, filming them in action has proven exceptionally difficult, with flashes of lightning being too quick for most recording devices. So while the BBC did embellish that footage, it's likely that a "super-charged volcanic ash cloud" (!) could really be that spectacular—we'd just have to record it first to see.

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Courtesy of Gem Diamonds Ltd.
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This Just In
Fifth Largest Diamond in The World Discovered in Southern Africa
Courtesy of Gem Diamonds Ltd.
Courtesy of Gem Diamonds Ltd.

The Letšeng diamond mine in the southern African nation of Lesotho is known for producing large, high-quality gems. As Bloomberg reports, a massive diamond uncovered there recently is the mine's most impressive yet. The 910-carat stone is roughly the size of two golf balls and weighs more than a billiard ball.

The diamond is thought to be the fifth largest ever discovered on Earth. Gem Diamonds Ltd., the company behind the discovery, said in a statement [PDF] that the "exceptional top quality diamond is the largest to be mined to date and highlights the unsurpassed quality of the Letšeng mine."

Beyond its size, the diamond is also remarkable for its purity. The D color Type IIa status means there are little to no nitrogen atoms muddying its color. Though Gem Diamonds hasn't revealed their price, the diamond is likely worth a huge amount: up to $40 million, analyst Ben Davis tells Bloomberg.

That's a steep price, but it's nowhere near the highest ever paid for a diamond at auction. Rare colored diamonds tend to fetch the highest bids: In 2015, the Blue Moon diamond sold for $48.5 million, and in 2017 the Pink Star was auctioned off for $71.2 million, making it the most expensive diamond of all time.

[h/t Bloomberg]

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Space
Mysterious 'Hypatia Stone' Is Like Nothing Else in Our Solar System
iStock
iStock

In 1996, Egyptian geologist Aly Barakat discovered a tiny, one-ounce stone in the eastern Sahara. Ever since, scientists have been trying to figure out where exactly the mysterious pebble originated. As Popular Mechanics reports, it probably wasn't anywhere near Earth. A new study in Geochimica et Cosmochimica Acta finds that the micro-compounds in the rock don't match anything we've ever found in our solar system.

Scientists have known for several years that the fragment, known as the Hypatia stone, was extraterrestrial in origin. But this new study finds that it's even weirder than we thought. Led by University of Johannesburg geologists, the research team performed mineral analyses on the microdiamond-studded rock that showed that it is made of matter that predates the existence of our Sun or any of the planets in the solar system. And, its chemical composition doesn't resemble anything we've found on Earth or in comets or meteorites we have studied.

Lead researcher Jan Kramers told Popular Mechanics that the rock was likely created in the early solar nebula, a giant cloud of homogenous interstellar dust from which the Sun and its planets formed. While some of the basic materials in the pebble are found on Earth—carbon, aluminum, iron, silicon—they exist in wildly different ratios than materials we've seen before. Researchers believe the rock's microscopic diamonds were created by the shock of the impact with Earth's atmosphere or crust.

"When Hypatia was first found to be extraterrestrial, it was a sensation, but these latest results are opening up even bigger questions about its origins," as study co-author Marco Andreoli said in a press release.

The study suggests the early solar nebula may not have been as homogenous as we thought. "If Hypatia itself is not presolar, [some of its chemical] features indicate that the solar nebula wasn't the same kind of dust everywhere—which starts tugging at the generally accepted view of the formation of our solar system," Kramer said.

The researchers plan to further probe the rock's origins, hopefully solving some of the puzzles this study has presented.

[h/t Popular Mechanics]

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