Underground Wonders

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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How to Spot Poison Ivy, According to a Scientist
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If you're a former scout, you've probably heard the rhyme “leaves of three, let it be.” This mnemonic device, used to steer intrepid outdoorspeople away from poisonous ivy and oak, is generally sound advice for ensuring you don’t come home with a nasty rash. Not all three-leaved plants are the enemy, though, and several harmless plants are often confused with poison ivy.

Microbiologist John Jelesko shared some tips with NPR for identifying this pernicious plant. First, it helps to know what you’re up against. Poison ivy is a master of disguise and can take many different shapes and sizes. It can appear in small patches, take the form of creeping vines or a bush, and can even mimic the appearance of a tree it has wrapped itself around. The leaves can have either “smooth, jagged, or lobed edges” and may or may not bear white or greenish berries.

If the plant has thorns, you can be sure it’s not poison ivy, whose mode of attack is a little more stealthy. In the city, Jelesko had found that climbing vines are the more common form; look out for ground-creeping vines in forested areas. While there are exceptions to this rule, Jelesko’s research found that poison ivy tends to take different forms depending on the landscape.

A longer middle stem and a hairy vine are also signs that you could be dealing with poison ivy. If you have a plant in your garden that you can’t identify, you can conduct a “black dot test” to see if it’s poison ivy. Put on a pair of gloves, tear a leaf in half, and place the sap on a sheet of white paper. If it’s urushiol oil (the rash-causing chemical in poison ivy), it will turn black within 30 minutes.

Sometimes, even our best efforts to identify poison ivy may fail. If you think you may have brushed up against it, don’t panic—take a shower within a few hours of contact. That should keep your chance of developing a rash at a minimum.

[h/t NPR]

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Art
A Rare Copy of Audubon's Birds of America Could Break Records at Auction
Christie's
Christie's

American artist and naturalist John James Audubon published The Birds of America in the first half of the 19th century, and his massive “double-elephant” folio of life-size bird illustrations remains one of the most ambitious nature books ever produced. On June 14, a rare edition of the four-book set is hitting the auction block, and it's expected to fetch up to $12 million—more than any Audubon book ever sold.

This edition of The Birds of America was owned by the dukes of Portland from around 1839 to 2012. Because it was stored on the shelves of the family's Nottinghamshire, England estate for nearly a century, the set's prints of watercolor drawings have remained remarkably well-preserved.

In 2012, the copy was auctioned off to philanthropist and businessman Carl W. Knobloch, Jr. for nearly $8 million. Knobloch donated the books to the Knobloch Family Foundation (KFF) before his death in 2016. Now, the KFF is sending the books to auction once again. This time, all proceeds of the sale will go to nature conservation.

Set of red leather-bound books.

New York City auction house Christie's describes the set in a listing as "among the finest copies in private hands of this icon of American art, and the finest color-plate book ever produced." Each of the 435 double-elephant folio pages measures 39.5 inches by 26.5 inches, the largest sheets Audubon could get his hands on at the time, and they feature 1037 birds from 500 species. The books are bound in red Moroccan leather with gold detailing on the borders and spines. The four-volume set also comes with the Ornithological Biography, a collection of five books describing the specimens in The Birds of America and their habits.

Christie's estimates the set will sell for $8 million to $12 million when the final bid is placed later this month. To date, the most expensive copy of The Birds of America was a first edition acquired from Sotheby's in London for $11.5 million. That sale also broke the record for the most expensive printed book ever sold at auction, a record held until 2013.

Illustration of American birds.

Illustration of American bird.

Illustration of American birds.

Illustration of American birds.

Illustration of American birds.

All images courtesy of Christie's

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