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8 Surprising Facts About the Deepest Part of the Ocean

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The deepest part of our oceans, the region from below 20,000 feet to the very bottom of the deepest sea trench, is known as the hadal zone. It's named after Hades, the underworld of Greek mythology (and its god). The majority of the hadal zone is made up of plunging trenches formed by shifting tectonic plates. To date, some 46 hadal habitats have been identified—about 41 percent of the total depth range of the entire ocean, and yet less than one quarter of 1 percent of the entire ocean. Scientists still know very little about this mysterious and difficult to study region, but what we have learned is astounding. 


To give some perspective, Mount Everest would fit inside the deepest sea trench on Earth, the Mariana Trench, with a few miles to spare. This helps explain why it has been so rarely explored—only three people have ever made it to the bottom of the Mariana trench: two scientists aboard the Trieste in 1960, and the film director James Cameron in 2012.

The trenches of the hadal deep are so remote that getting equipment or people to such depths is extremely difficult. This is compounded by the fact that the underwater pressure at that depth—approximately 8 tons per square inch, roughly that of 100 elephants standing on your head—causes ordinary instruments to implode.

Scientists venturing so far down require special equipment that can withstand the immense pressure, but even those can be unreliable. In 2014, the remote unmanned sub Nereus became the latest in a long line of research probes to be lost during a mission. Nereus was built by Woods Hole Oceanographic Institution (WHOI) and had completed several ground-breaking missions into the hadal zone, including in 2009 reaching the bottom of the Mariana Trench. But during its last mission, into the Kermadec Trench just off New Zealand, the sub imploded and broke apart, likely because of the intense water pressure. You can see some footage of the Nereus sampling the seafloor of the Mariana Trench during its 2009 expedition. 


To measure the very deepest parts of the ocean, scientists use bomb sounding, a technique where TNT is thrown into the trenches and the echo is recorded from a boat, allowing scientists to estimate the depth. While scientists question the sensitivity of the method, even the rough results are impressive: So far, in addition to the Mariana Trench, four other trenches—the Kermadec, Kuril-Kamchatka, Philippine, and Tonga, all in the Western Pacific Ocean—have been identified as deeper than 10,000 meters (32,808 feet).


The first expedition to take samples from the hadal zone was the trail-blazing HMS Challenger Expedition, working from 1872 to 1876. Scientists on board managed to extract samples from 26,246 feet under the ocean, but at that time were not able to confirm if the animal remains they found were actually living at that depth or were simply the remains of marine creatures from higher up in the ocean which had sunk to that depth after death. It was not until 1948 that a Swedish research vessel, Albatross, was able to collect samples from 25,000 feet, which proved that creatures existed at greater depths than 20,000 feet, and thus that the hadal zone was inhabited.

But it wasn’t until 1956 that Jacques Cousteau took the first photograph of the hadal zone. Cousteau submerged his camera to the sea-floor of the Romanche Trench in the Atlantic Ocean, some 24,500 feet down, providing the first glimpse of this previously unseen part of the ocean.


Studying the creatures that survive in the hadal zone can be very challenging. Prior to 2008, most species were described from just one sample, often in a poor state. (One scientist described most hadal samples as “shrivelled specimens in museums.”) In 2008, in a huge leap toward understanding deep sea creatures, the first images of live organisms from the hadal zone were recorded. The Japanese research vessel Hakuho-Maru deployed a freefall baited lander in the Japan Trench in the Pacific Ocean, becoming the first scientists to produce images of live hadal creatures in situ. The camera caught pictures of hadal snailfish (Pseudoliparis amblystomopsis), which are thought to be the most prevalent species at hadal depths. The images surprisingly showed swarms of active fish feeding on tiny shrimp—overturning ideas that fish at this depth would be solitary, sluggish creatures barely eking out an existence. A 2016 paper went on to identify live snailfish at a depth of 26,722 feet—the deepest confirmed sighting of a live specimen.


Recent expeditions such as the HADES project in the Pacific suggest that fish are not found below 27,560 feet. But the hadal zone extends to 36,000 feet. Whitman College marine biologist Paul Yancey hypothesizes that fish reach a limit around 27,500 feet because proteins at such great depths cannot build properly. To counteract this, deep-sea fish have developed an organic molecule known as trimethylamine oxide, or TMAO (this molecule also gives fish their “fishy” smell), which helps proteins work at high pressure. Shallow water fish have fairly low levels of TMAO, while deep sea fish have increasingly high levels. Yancey proposes that the amount of TMAO required to counteract the huge pressure below 27,560 feet would be so great that water would begin to flow uncontrollably through their bodies, killing the fish.

Below 27,560 feet however, other types of creatures do exist, such as shrimp-like hadal amphipods. These creatures scavenge on the waste and dead bodies from sea creatures which float down from above, amazingly thriving at great depths.


In the 1970s, tons of toxic pharmaceutical waste—the equivalent of 880 Boeing 747s—was dumped into the Puerto Rico Trench. At the time Puerto Rico was a large producer of pharmaceuticals, and the dumping was allowed as a temporary measure while a new wastewater treatment site was built. Inevitably, delays meant that dumping continued at the site into the 1980s. Samples taken from the dump site indicated that ecosystems were seriously damaged by the pollutants, with a 1981 study revealing “demonstrable changes in the marine microbial community in the region used for waste disposal.”


Creatures that thrive in extreme environments such as the hadal zone are called extremophiles. These creatures can withstand very low temperatures, high pressures, and can survive with little or no oxygen. Studying these extraordinary animals can lend great insights to scientists, indicating how life might persist in space where no oxygen is present. Microorganisms such as Pyrococcus CH1 have been found in deep sea vents, gifting scientists with an idea of the type of life that could exist on planets such as Jupiter’s moon, Europa.


One of the most excitingly named creatures found in the hadal zone is the enigmatic supergiant, also known as Alicella gigantea. This amphipod is at least 20 times the size of its shallower-dwelling cousins. This makes them sound super exciting, until you realize they’re still miniscule creatures related to the humble sand hopper—a tiny beast often found popping out of the seaweed at the beach at high speed. The largest specimen of supergiant ever found was a 13.4-inch-long female, found in a trench in the Pacific Ocean.

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IA Collaborative
Lovely Vintage Manuals Show How to Design for the Human Body
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IA Collaborative

If you're designing something for people to hold and use, you probably want to make sure that it will fit a normal human. You don't want to make a cell phone that people can't hold in their hands (mostly) or a vacuum that will have you throwing out your back every time you clean the house. Ergonomics isn't just for your office desk setup; it's for every product you physically touch.

In the mid-1970s, the office of legendary industrial designer Henry Dreyfuss created a series of manuals for designers working on products that involved the human body. And now, the rare Humanscale manuals from Henry Dreyfuss Associates are about to come back into print with the help of a Kickstarter campaign from a contemporary design firm. Using the work of original Henry Dreyfuss Associates designers Niels Diffrient and Alvin R. Tilley, the guides are getting another life with the help of the Chicago-based design consultancy IA Collaborative.

A Humanscale page illustrates human strength statistics.

The three Humanscale Manuals, published between 1974 and 1981 but long out-of-print, covered 18 different types of human-centric design categories, like typical body measurements, how people stand in public spaces, how hand and foot controls should work, and how to design for wheelchair users within legal requirements. In the mid-20th century, the ergonomics expertise of Dreyfuss and his partners was used in the development of landmark products like the modern telephones made by Bell Labs, the Polaroid camera, Honeywell's round thermostat, and the Hoover vacuum.

IA Collaborative is looking to reissue all three Humanscale manuals which you can currently only find in their printed form as historic documents in places like the Cooper Hewitt design museum in New York. IA Collaborative's Luke Westra and Nathan Ritter worked with some of the original designers to make the guides widely available again. Their goal was to reprint them at a reasonable price for designers. They're not exactly cheap, but the guides are more than just pretty decor for the office. The 60,000-data-point guides, IA Collaborative points out, "include metrics for every facet of human existence."

The manuals come in the form of booklets with wheels inside the page that you spin to reveal standards for different categories of people (strong, tall, short, able-bodied, men, women, children, etc.). There are three booklets, each with three double-sided pages, one for each category. For instance, Humanscale 1/2/3 covers body measurements, link measurements, seating guide, seat/table guide, wheelchair users, and the handicapped and elderly.

A product image of the pages from Humanscale Manual 1/2/3 stacked in a row.

"All products––from office chairs to medical devices—require designs that 'fit' the end user," according to Luke Westra, IA Collective's engineering director. "Finding the human factors data one needs to achieve these ‘fits' can be extremely challenging as it is often scattered across countless sources," he explains in a press release, "unless you've been lucky enough to get your hands on the Humanscale manuals."

Even setting aside the importance of the information they convey, the manuals are beautiful. Before infographics were all over the web, Henry Dreyfuss Associates were creating a huge compendium of visual data by hand. Whether you ever plan to design a desk chair or not, the manuals are worthy collectors' items.

The Kickstarter campaign runs from July 25 to August 24. The three booklets can be purchased individually ($79) or as a full set ($199).

All images courtesy IA Collaborative

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Winston Churchill’s Audacious Plan to Build an Aircraft Carrier Out of Ice
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iStock/Central Press/Hulton Archive/Getty Images

Winston Churchill was enjoying a steamy bath when he discovered the secret to winning World War II floating in his tub. It was 1942, and Lord Louis Mountbatten, the Chief of Combined Operations and Britain’s head honcho for unconventional warfare, had stormed into the Prime Minister’s bathroom with unexpected news. (It’s not as strange as it sounds. Churchill regularly conducted meetings from his tub.)

“I have a block of new material that I want to put in your bath,” Mountbatten explained. He dropped a hunk of ice between Churchill’s legs. The two watched in awe as the ice refused to melt.

At the time, Churchill was in a pickle. The Soviets were fighting Germany on the eastern front, but the UK, which had yet to successfully invade Europe from the west, sat in limbo. Knowing that Britain was utterly dependent on imports, German U-boats routinely targeted merchant ships bound for the UK, sending the food and goods intended for citizens and soldiers to the bottom of the ocean.

Those ships needed protection badly, but aircraft based on shore didn’t have the range to offer cover, leaving vessels to navigate a perilous 300-mile stretch of undefended ocean on their own. Experts called this vulnerable territory the "mid-Atlantic gap." Others simply called it "The Black Pit."

Mindful of the gap, Churchill believed a series of floating airfields in the Atlantic could close the distance between his air force and enemy submarines. With aircraft carriers in short supply, he wanted to establish a string of unsinkable floating islands that could serve as hangars and refueling depots. The catch? These buoyant land strips had to be constructed out of a material other than steel; the Allies needed every ounce of the metal for weapons, tanks, and battleships.

Churchill was convinced the solution was bobbing in his bathwater.

For a time, the British seriously considered using ice as a construction material for their floating airfields. Ice, after all, doesn’t sink. Repairs would be easy: just add water. Churchill naively believed it was as simple as chiseling off a slice of the Arctic ice shelf and tugging it back to Cornwall.

There were obstacles, of course. Ice melts, and nobody wanted to send a fleet of floating islands into the Atlantic just to watch them disappear. Ice is also brittle, and Churchill's men knew that if an airfield were too thin, a bomb could split it in two. Icebergs have also been known to violently flip over, and the same went for Churchill’s airfields, which were one well-placed strike away from dumping hundreds of flyboys into the drink.

Geoffrey Pyke, the scientist who cooked up the idea of ice-based airfields in 1942, directed the researchers of Britain's Combined Operations to find a way to make strong, unmeltable ice. He focused his attention on a little-known report by Herman Mark, a Vienna-based professor of chemistry who had fled the Nazis, which explained how a simple mixture of wood pulp, sawdust, or cotton could reinforce ice in the same way that steel wires bolster concrete.

The report was no joke. Pyke's men found that even a small addition of wood pulp worked miracles: It insulated the ice, prevented most melting, and resulted in blocks of building material that were as resilient as concrete. Pyke's men named it “Pykrete,” and when the Prime Minister saw it floating in his bathtub, he was sold.

“It would be of ship-like construction, displacing a million tons, self-propelled at slow speed,” Churchill wrote in his 1951 book Closing the Ring, “with its own anti-aircraft defense, with workshops and repair facilities, and with a surprisingly small refrigerating plant for preserving its own existence.” It would be called Project Habakkuk, named after the Hebrew prophet who wrote, “Look at the nations, and see! Be astonished! Be astounded! For a work is being done in your days that you would not believe if you were told.”

The code name was apropos. The proposed aircraft carrier was destined to be 2000 feet long and 100 feet thick. (Ten times thicker than the average sheet of Arctic ice, by the way.) It would have a cruising range of 7000 miles, requiring 26 electric motors and a 15-story rudder. It would displace 26 times more water than the largest ship in the world.

The carrier's awesomeness didn't end at its massive size. Max Perutz, a scientist who worked on the project, wrote in The New Yorker that the “bergships were to carry enormous tanks full of supercooled water—liquid water cooled below its normal freezing point—which could be sprayed at the enemy to solidify on contact.”

In other words, freeze rays.

In 1943, the British presented the idea to American commanders during a secret meeting. Accounts vary, but as Perutz told it, Lieutenant Commander Douglas Grant brought two blocks of ice—one regular, one Pykrete—whipped out a pistol, and fired two shots. The first bullet shattered the ice. The second bullet hit the Pykrete, ricocheted, and tore into a high-ranking officer’s shoulder. The Pykrete, however, was unharmed.

The Americans signed on.

That summer, the military built a prototype in Alberta, Canada. Local mills supplied the pulped wood, while laborers at a 200-acre refrigeration plant froze water into monolithic cubes. Within months, a 60-foot-long ice boat rested on a nearby lake. It weighed as much as five blue whales.

But the project went no further. By late 1943, Allied factories had built new fleets of aircraft carriers. With the flying range of new military airplanes (aptly named very-long-range aircraft) improving and the pace of manufacturing gaining steam, the mid-Atlantic gap had already closed. Improvements to radar and an increase in destroyer escorts spelled trouble for Germany's U-Bootwaffe, which would lose a quarter of its submarines that year. Officials poring over production numbers concluded that constructing a fleet of berg-boats was an unnecessary money trap. They scuttled the mission, and the Pykrete barge was abandoned to slowly melt.


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