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Underground Wonders

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More than just a hole in the ground, every cave has its own story. Caves are born in many different fashions, which leave them with different personalities.

Lava Tubes

Lava tube caves are formed when lava flows down the side of a volcano. The lava exposed to the air cools and hardens first, while the lava underneath continues to flow out, leaving an open tube behind when the eruption is finished. The longest and deepest lava tube is 40-mile-long Kazumura Cave on the southeast slope of Mauna Loa in Hawaii.

Tree Molds

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Mount St. Helens has plenty of lava tube caves, and some lava tree molds. The tree molds were formed when an eruption 1,950 years ago knocked down trees and covered them with lava. When the trees burned, the opening left behind would be a perfect mold of the logs.

Sea Caves

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Sea caves are erosional caves, formed by the action of waves against rock, usually along an existing fault. The Blue Grotto of Capri is a popular and photogenic cave due to the appearance of light from the bottom of the cave. Sunlight enters the cave through underwater channels and reflects off the limestone floor.
More types of caves, after the jump.

Wind Caves

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Wind caves are formed by erosion of sandstone by blowing wind. They tend to be pretty shallow and rounded. Gaviota, California is home to some beautifully sculpted wind caves.

Glaciar Caves

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Glaciar caves are also erosional, usually carved by mountain streams flowing into glaciers, but can also be formed by volcanic heat from below. Pictured is a cave carved by water flowing into the Fox Glacier in New Zealand.

Limestone Caves

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Solutional caves are formed when the existing rock is dissolved. The most common type is the limestone cave, because rainwater and groundwater contain acids which dissolve limestone over time. An example is Mammoth Cave system in Kentucky, the world's most extensive cave system at 367 combined miles (and still not completely mapped)!

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Another limestone cave formation, the Sarawak Chamber in the Gunung Mulu National Park in Malaysia is the world's largest single cave chamber, measuring 2,300 feet long, 1,300 feet wide and at least 230 feet high!

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In New Mexico, Lechuguilla Cave and Carlsbad Caverns are a different kind of solutional cave. They were formed by sulphurous acids rising from below. The minerals from the acidic fumes leave amazing and fragile gypsum and sulphur formations such as chandeliers, soda straws, and cave pearls. Although Carlsbad Caverns is a major tourist draw, the more recently-mapped Lechuguilla Cave is off-limits to visitors in order to preserve the environment.

Salt Caves

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Salt caves are also solutional caves, forming and collapsing relatively quickly. The world's longest salt cave (nearly four miles) was discovered just last year on Qeshm Island off the coast of Iran.

For all kinds of information on caves, I recommend a tour of The Virtual Cave.

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Courtesy of Nikon
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science
Microscopic Videos Provide a Rare Close-Up Glimpse of the Natural World
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Courtesy of Nikon

Nature’s wonders aren’t always visible to the naked eye. To celebrate the miniature realm, Nikon’s Small World in Motion digital video competition awards prizes to the most stunning microscopic moving images, as filmed and submitted by photographers and scientists. The winners of the seventh annual competition were just announced on September 21—and you can check out the top submissions below.

FIRST PRIZE

Daniel von Wangenheim, a biologist at the Institute of Science and Technology Austria, took first place with a time-lapse video of thale cress root growth. For the uninitiated, thale cress—known to scientists as Arabidopsis thalianais a small flowering plant, considered by many to be a weed. Plant and genetics researchers like thale cress because of its fast growth cycle, abundant seed production, ability to pollinate itself, and wild genes, which haven’t been subjected to breeding and artificial selection.

Von Wangenheim’s footage condenses 17 hours of root tip growth into just 10 seconds. Magnified with a confocal microscope, the root appears neon green and pink—but von Wangenheim’s work shouldn’t be appreciated only for its aesthetics, he explains in a Nikon news release.

"Once we have a better understanding of the behavior of plant roots and its underlying mechanisms, we can help them grow deeper into the soil to reach water, or defy gravity in upper areas of the soil to adjust their root branching angle to areas with richer nutrients," said von Wangenheim, who studies how plants perceive and respond to gravity. "One step further, this could finally help to successfully grow plants under microgravity conditions in outer space—to provide food for astronauts in long-lasting missions."

SECOND PRIZE

Second place went to Tsutomu Tomita and Shun Miyazaki, both seasoned micro-photographers. They used a stereomicroscope to create a time-lapse video of a sweating fingertip, resulting in footage that’s both mesmerizing and gross.

To prompt the scene, "Tomita created tension amongst the subjects by showing them a video of daredevils climbing to the top of a skyscraper," according to Nikon. "Sweating is a common part of daily life, but being able to see it at a microscopic level is equal parts enlightening and cringe-worthy."

THIRD PRIZE

Third prize was awarded to Satoshi Nishimura, a professor from Japan’s Jichi Medical University who’s also a photography hobbyist. He filmed leukocyte accumulations and platelet aggregations in injured mouse cells. The rainbow-hued video "provides a rare look at how the body reacts to a puncture wound and begins the healing process by creating a blood clot," Nikon said.

To view the complete list of winners, visit Nikon’s website.

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environment
Great Britain's Last Snow Patch Is About to Disappear Completely for the First Time in a Decade

Until recently, it was easy to find snow in Great Britain at any time of the year—you just had to know where to look. In previous Septembers, the island has been home to as many as 678 snow patches, residual pockets of snow and ice whose climates and topographies keep them frozen through the summer. This year, though, only two of Britain's snow patches have survived the summer. And the island is now on track to be completely snowless by the end of the season, Atlas Obscura reports.

Snow patches vary in size and durability, with some melting completely by late summer and others remaining a permanent fixture of the landscape. Garbh Choire Mor—a steep glacial depression on top of Scotland's third-highest mountain, Braeriach—contains two of the oldest snow patches in Britain, known as the Pinnacles and the Sphinx. The Pinnacles snow patch dissolved into a puddle earlier this month, and the Sphinx snow patch, the last surviving snow patch in Great Britain, is expected to do the same in the next few days.

Scotland experienced uncharacteristically hot weather this summer, with temperatures creeping into the low 90s as early as May. But more significant than the sweltering summer was the dry winter that preceded it. Below-average snowfall last year meant this year's snow patches were already smaller than usual when temperatures started heating up. If the Sphinx snow patch does vanish before winter arrives, it will mark the first time in over a decade and just the sixth time in the last 300 years that England, Scotland, and Wales are without a single patch of snow.

The Sphinx snow patch, though currently a measly version of its previous self, is still visible for now. But Iain Cameron, a veteran "snow patcher" who writes an annual report on snow for the UK's Royal Meteorological Society, says it could be gone as soon as Wednesday, September 20.

He's currently camped out on Garbh Choire Mor, waiting to document the patch's final moments. You can follow his updates on Twitter.

[h/t Atlas Obscura]

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