"Deadlymotionpressure,the  deep's ultimate stealth weapon." "Pressureisatremendous natural force." "Itcancripple." "Pain,numbness,lossof function." "Crush." "SeemsI 'mjuststuck." "Dead silence." "Orimplodein afractionofa second." "Youwouldneverknowwhat hit you." "Descendbeneaththeocean's5 deadly pressure zones, each more devastating than the last, to the deadliest spot on Earth." "7milesdownisextremely hostile, not unlike a large SUV on a dime." "Nothingescapesthefatal pressure of the underwater universe." "Ofalltheplanetsinthe known universe, planet Earth does something unique." "It supports water." "A lot of water." "About70%of thisplanethas ocean water covering it." "The average depth's about 2 miles." "And so, if you look at it from space, at the Earth, you could make the case that we should be called planet Ocean, not planet" "Earth." "TheEarthis coveredbya  blanket of liquid totaling 331 million cubic miles." "Rolled into a ball, that would be roughly 1/3 the size of the" "Moon." "At 8 pounds per gallon, all that liquid pulled by gravity toward the center of the earth weighs some 3 sextillion pounds." "The weight of water is the greatest barrier to exploring the underwater universe." "Humans feel it as pressure, the deadliest force in the deep." "Thedeeperyougointhe ocean, the nastier it gets." "The deeper you go, the more water there is above you, and so, the greater the weight of the water becomes." "Theweightof theoceansis divided into 5 layers, or zones, each deeper, darker, colder, and deadlier than the last." "At the very bottom, some 36,000 feet down, is the most lethal place on Earth." "At36,000feet,the  pressure's about 8 tons per square inch." "So, you think of 8 tons on top of a--1 square inch, that's--uh, it makes you think." "Cananythingsurvivethe grip of the underwater universe?" "To better understand the immense forces at play, it's necessary to descend through each of the 5 pressure zones, beginning at the top." "Zone 1, the epipelagic." "Otherwise known as "the sunlight zone."" "It's home to the majority of ocean life." "Although relatively shallow and seemingly welcoming, pressure here is already a formidable enemy." "Thefirst33 feetisreally the most dangerous for an uncertified diver." "Jacques Cousteau led a scuba-diving revolution in the" "1940s, giving humans unprecedented access to the epipelagic zone for the first time." "It'sonlyin thelastless  than 100 years that we are starting to explore and go under the surface to see what's there." "Butnoteverydiverisfully  aware of the power of water pressure, especially so close to the surface." "Just off the Florida Keys, a family of amateur scuba-divers prepares for a routine recreational dive." "Wetookup scubadivingasa family." "We all got certified about 6 years ago, so we started incorporating that in our vacations together." "It was just kind of a family thing that we could all do together." "AndrewDevliegerandhis twin brother Matthew planned to spend the day exploring a popular dive site." "Allright." "Wedescendedslowly." "We had great visibility." "Clear, warm water." "A perfect day." "Buttheshallowestwaters hide the planet's most extreme pressure shift." "Wherewearenow ,atsea level, the weight of the air above you is 1 atmosphere, 1 bar." "Um, so, if you look up to the sky or to the highest mountain, that height gives you 1 bar of pressure, 1 atmosphere." "1atmosphereof pressure equals 14.7 pounds per square inch, or psi, the weight of 1 square inch of our Earth's airspace." "Because water is 800 times heavier than air, the weight of the entire 10 miles of atmosphere is matched in just the first 33 feet of seawater." "Thefirstatmosphere,the  first 30 feet, it's the hardest to get used to." "I knew that I had to go slow, clearing my ears and equalizing to the pressure difference." "Assoonas adiverentersthe water, pressure begins to compress the air pockets inside his body." "Ifyouweretodescend holding your breath, as the pressure increased, your lungs would get squeezed tighter and tighter and tighter until they were just, um, nothing but bloody pulp." "That'sthesecretofthe regulator." "It allows you to breathe air at the ambient pressure, at the pressure of the level of the water where you are so not to have an accident." "AndrewandMatthewdescendto 130 feet." "The pressure here is 4 atmospheres, the equivalent of 4 bowling balls pressing down on every square inch of the body." "Wewereswimmingaround." "We explore the ship." "Visibility over 100 feet." "Gorgeous dive." "Thoughthebrothersare  breathing pressurized air, every minute in water's grip takes a toll on their bodies." "Whenyoubreatheatincreased pressure, your lungs are exposed to a higher pressure." "It's going to push more gas into your bloodstream." "Theonlywaytogetridof  that gas is to slowly expel it or decompress on the way back to the surface." "Andmybrothermotionstome , it's time to go up." "We've been diving for 6 or 7 years and this instance didn't seem any different than all the other times where he showed me his gauge saying he's to ascend." "So, I figured, "ok, it's time to go up."" "I looked around for where" "Matthew was and I couldn't find him." "I looked up and there was a diver who was significantly higher than I was." "Matthewisascendingfast, too fast." "Thatairin yourbloodstream, as you go up, is expanding because it's compressed at the ambient pressure." "You have to go slowly so whatever is inside your body gets dispersed or disposed of so you don't have blockage." "Ifinallygettotheboatand that's when Matthew started having a hard time breathing." "Diverswhorunintotrouble can find themselves experiencing a wide range of perplexing symptoms." "Pain,numbness,paresthesias, uh, loss of function, weakness..." "Paralysis..." "Arterialgasembolism..." "Unconsciousnessorlossof memory..." "Immediatecardiovascular collapse and death." "Thehumanbodydoesnot respond well to large changes in differential pressure." "Decompressionsickness,or" ""the bends," is a disease of the industrial revolution." "It was observed initially by folks who used caisson, great big cylinders that would be placed underground to--to force the water out of mines." "The deeper they got and the longer they stayed, they began to have pains in their joints and eventually, they started to have fatalities." "Althoughmuchis still unknown about why the body reacts so powerfully to changes in pressure, scientists now understand that it attacks the body from the inside out." "A soda bottle demonstrates how." "Ifyoutakeasoda bottleand you look at it before you open it, before you twist that top, there are no bubbles that you can see." "You'vegotgassesthatare suspended in that liquid, that carbon dioxide that's in the soda." "When you open it, you hear that fizz." "[Fizzing]" "That's when you're gonna see the bubbles." "That's the gas in the liquid trying to come to a new equilibrium point with its environment." "That is what you're trying to prevent when you're trying to prevent decompression sickness." "ButinMatthew'scase,it's  too late." "His bloodstream is already a mass of bubbles." "Underwater Universe 1x03 Fatal Pressure Original Air Date on March 16, 2011" " sync, corrected by elderman " "Oftheunderwateruniverse's 5 fatal pressure zones, the first and shallowest, the epipelagic claims more victims per year than any other." "As twin brothers Andrew and" "Matthew Devlieger surface from a 1/2-hour scuba dive, it's clear that something has gone wrong." "Wedidn'tknowwhattothink ." "Matthew couldn't move his legs and he was short of breath, gasping for air and gripping his wetsuit." "It was definitely scary." "We radioed the Coast Guard and we raced home." "ThegasbubblesinMatthew's bloodstream are threatening to block his circulation entirely." "It'slikeavaporlock inthe carburetor on your car." "You don't get any gas down to the engine and the car stops." "Well, if you don't get blood pumped around to your body and to your brain, you will stop, too, and it doesn't take very long at all." "45minutesaftersurfacing, the twins make it to the hospital." "Now, the question for Matthew's doctors is how to shrink the deadly bubbles back to size." "The answer?" "More pressure." "Theyputhimina  decompression chamber and they put him in it for a long time." "Matthewisrushedintoa sealed capsule known as a hyperbaric chamber." "The air pressure inside is increased to mimic 3 atmospheres of water pressure, enough to start shrinking the bubbles." "Ifthebubblesare not ,uh,  reduced in size, they may continue to accumulate in the joints and in the spinal cord and other areas of the body and continue to create more damage." "[Slam]" "Matthewissealedinthe chamber for 2 days." "3 days." "But doctors see no improvement." "Inmanycases,duringthe treatment, the symptoms will abate." "However, in Matt's case, the symptoms did not appear to be resolving." "[Andrew sighs]" "Itwasscary." "We were definitely getting more and more concerned." "Finally,after5daysof treatment, Matthew appears to be over the worst." "Though he survives, he will pay a price." "Iwasin thehyperbaric chamber for 5 days, 5 hours at a time." "I still couldn't move my legs after the fifth day." "Uh, I didn't really have much sensation, either." "And the doctor said-- heisparalyzedfromthe chest down." "Today, despite being told he would never walk again, he has regained some movement in his legs." "Matthew's case is rare." "Only 2% of scuba divers suffer the bends each year, and fewer still are paralyzed." "Idefinitelyhavegaineda new respect for how much pressure there is when you go under the ocean." "Ididn'tunderstandhow  dangerous water pressure could be." "It must command our respect." "Matthewbarelysurvivedthe  deadly force of pressure in the shallowest of the 5 ocean zones." "But what happens to the human body in the ocean's next pressure zone?" "Zone 2, the mesopelagic." "Also called the twilight zone because the sun's rays cannot penetrate any deeper." "The mesopelagic plunges from 600 to 3,000 feet where pressures mount to 15,000 psi." "The weight of 2 all-terrain vehicles on each square inch of the human body." "This deep, oxygen becomes scarce and animals are few and far between." "In order to venture here, a new kind of diving technology is necessary." "Intheearlysixties,there was a group of people at the" "Naval Medical Research" "Institute, uh, that came up with an idea that you could treat the body like a sponge." "Whenyouexposeadrysponge to water, it will expand until it becomes completely saturated." "At that point, it will stop absorbing water and stabilize." "In a similar way, the human body can also be saturated." "Thesaturationdive'sadive  in which you have come in complete equilibrium with the gasses that you're breathing." "Whilestillat thesurface, divers are pressurized inside a sealed chamber to match their working depth." "Yourearsstarttoclick." "You can feel your cartilage compress as you get deeper." "It depends how deep you're going, but it may take 3, 4, 5," "6 hours to get you down to depth, but your body will adjust and it will get saturated and it will get used to it." "Oncefullysaturated,divers are lowered down to the ocean floor inside an attached diving bell." "Whenyougetdowntothesea bed or wherever you're working, you can open the door to the bell, and because the 2 pressures are exactly the same, the water won't come rushing in." "You can stay for 12 hours or 28 days." "Your decompression time won't change." "As long as you stay at that pressure, at the end of your month, you will only have to do" "3, 4 days, 5 days decompression." "It takes away the need to decompress every time you dive." "Sincetheearlydaysof saturation diving, the race has been on to find out how much water pressure the human body can withstand." "Inthe1960sand 1970s,it was very much the Wild West and people would get hurt every now and again, and there were quite a few fatalities." "Bythelate1970s,no" "American team has been deeper than 1,000 feet in the open ocean and survived." "Scientists at Duke University announce a series of virtual test dives below 1,000 feet." "They name the project "The" "Atlantis Experiment."" "Youwantthatbeinthe safest place you can be if something goes wrong." "If you're doing it in the ocean, there is a lot more risk, obviously, than there is if you have a controlled situation." "Agymnasium-sizedresearch facility is built to simulate deep ocean conditions." "Inside a 7-foot wide pressure chamber, nicknamed "Golf Ball,"" "the scientists plan to push 3 test divers to their limit." "Nooneknewatthetimehow deep a human could dive." "Thekeyto saturationdiving is breathing the right combination of gasses." "Ifyouswitchfromairtoa mixture of different gasses, that allows you to stay longer and also go deeper." "Theairwe breatheuphere , largely a mix of 78% nitrogen and 20% oxygen, becomes deadly down there." "Theexposureof humansto nitrogen under pressure, uh, can have a narcotic effect." "It can impair your judgment." "You can have nitrogen narcosis to the point where, uh, you take your regulator out of your mouth and try to feed it to a fish." "You can have oxygen toxicity to the point where your body goes into convulsions." "Byreplacingmuchof the oxygen and nitrogen with helium, a less narcotic gas at depth, saturation divers can remain healthier longer." "But by 1980, the mix has yet to be perfected." "No one has gone deeper than 1,000 feet without adverse side effects." "Breathing helium, it turns out, is not without risk." "Youcanseethe effectsof pressure when you dive on helium." "The deeper you go and the faster you go, the more severe the effects become." "Themanin chargeofthe experiment, Dr. Peter Bennett, hopes to refine the mix and eliminate side effects." "But first, he needs human volunteers." "Therearepagesofconsent forms." "You need to know that you-re volunteering for something which could possibly end in your death." "Aftera gruelingselection process, 3 civilian divers are picked to serve as human test subjects." "The leader is a North Sea commercial saturation diver named Steve Porter." "Iknewtheseguyswere the experts." "They were best in the world at it, and that's why I wanted to come here and be part of this." "Althoughthedepthis simulated, the danger is real." "Once fully surated, there is no easy escape for the men if something goes wrong." "They'reloadedwithgas and  they have to have at least 31 days to get that gas out, otherwise, they're going to get decompression sickness." "It was a risk, a big risk." "After2 successfultest dives, one to a record-breaking" "2,132 feet, the researchers are ready to go for a new world record." "StevePorterandhis teamare sealed inside the chamber." "20 feet away at the control center, Dr. Bennett begins to gradually increase the pressure." "Andthey'regoingintoano man's land at that kind of depth." "You have no idea what's going to happen." "3menareabouttoattempta record-setting virtual dive into the underwater universe's second of 5 fatal pressure zones, the mesopelagic, between 600 and" "3,000 feet deep." "Theyknewtheyweregoing into the unknown." "The consent form ends where the potential risk is death." "It had to be written and they signed the consent form and made that judgment." "OnthemorningofOctober25, 1981, the test divers inside the pressure simulation chamber are experiencing the initial phase of the experiment." "You'regoingdowntoabout 1,000 feet very, very quickly." "You're hot, you're--you're getting this really rapid compression." "Uh, it's uncomfortable as the devil." "Porterandtheothershave  already passed the usual working depth of most saturation divers." "Though they are beginning to experience the physical effects of pressure, they are far from experiencing the reality of working in the mesopelagic zone." "Thecoldis yourbiggest enemy, as well as the pressure." "You take your glove off and immediate pain on your hands, you feel it straight away." "TonyGroomhasspentthe majority of his career 600 feet below the surface fixing oil rigs in the frigid North Sea." "It'sverysimilartobeingan" "Astronaut." "Pressures are pretty similar." "You've got a vacuum in space and you've got huge pressure under the sea." "Your movements are restricted like they are in space." "It's slower." "You can be walking in the water all day and you're absolutely exhausted because every movement is hard." "AtDukeUniversity,the test divers are finding out that despite the relative comfort of their dry research facility, the effects of pressure are becoming more debilitating the deeper they go." "Theair,it getssothick that your nasal passages won't support breathing." "You can't get enough air in." "So, you've got to breath through your mouth all the time." "Theairat thatdepthbehaves a lot different than the air we're in right now." "It almost takes on liquid properties." "Ifyouapplyenoughpressure to gas, it compresses the molecules together so much that they experience a phase shift and transform from a gas to a liquid." "Youcouldphysicallyfeelthe density of the air, just moving around in it, breathing it." "Byday2, StevePorterand his team reach their previous record of 2,132 feet of simulated seawater pressure." "Itwaslookingsogood at this maximum depth we couldn't believe it, so we said, "well, maybe we haven't reached the barrier yet, you know?" "Why don't we just try to go on a little excursion to 2,250?"" "Onday12 ,withthe divers' consent, Dr. Bennett gives the command." "As the pressure increases to 1,023 pounds per square inch, the physical side effects are immediately intensified." "Ifyouhadtosneeze,it would tear the top of your head off." "The pressure build-up inside it, it just--it hurt like the devil." "Ah-choo!" "Andworse,theirmindsbegin to play tricks." "Yougetthesehorrible technicolor dreams that just drive you nuts." "That shook me quite a bit a number of times." "Underextremepressure, helium is known to cause animals to go into convulsions and some divers to hallucinate." "Despite the side effects, Steve" "Porter and the other test divers manage a full day at 2,250 feet, setting a world record." "But they pay a price for glory." "35 long days of decompression, cut off from the outside world." "Therewasno in-between." "There's no shortcuts." "They can hand you stuff through the medical lock, but when something went wrong, it was all up to me to take care of it." "Themenemergeexhausted,but alive." "Bennett's experiment is a success, but this is the deepest simulated saturation dive he will ever attempt." "Therearelimitationsofthe human body as to how much pressure you can stand." "I personally was quite glad when we finished at 2,250 foot." "I would not like to go to 3,000 or 6,000 foot." "I don't even take humans there." "Todescendanydeeperthan  the mesopelagic zone means withstanding more pressure than the human body can handle." "Zone 3, the bathypelagic." "The midnight zone, beyond the reach of sunlight." "The pressure in this place of perpetual night, close to 5,800 psi, the equivalent of a Chevy" "Suburban on every square inch of the human body." "Inorderto getdeeperthan  the human body can go by itself, you would need to use an unmanned vehicle or a submersible." "Forthousandsof years,men  have tried to make vessels to travel underwater." "But as of the 1920s, not one of them has made it below 400 feet." "Theknowledgeof thedeep ocean in the 1920s was minimal, at best." "Mostbiologistsbelievedthat there was no life in the deep ocean." "That the temperature was too cold and the pressure from all the water above was too high." "Mankind'sfirstattemptto reach the bathypelagic zone takes place in the early 1930s." "Not by any of the world's navies, but by 2 daring civilians with big dreams and no safety net." "William Beebe and Otis Barton." "WilliamBeebewasone ofthe most famous Naturalists in the world." "He was the Director of the Bronx" "Zoo." "He was an Ornithologist by avocation." "Beebeteamsup withayoung engineer named Otis Barton, who has a design he believes will allow them to reach the bathypelagic zone." "He calls it the Bathysphere." "BuildingtheBathyspherewas  essentially like building an" "Apollo spacecraft, except a couple of kids doing it in their backyard." "TheBathysphereis a4  1/2-foot wide cast steel hollow ball with walls 1-inch thick." "The 5,000-pound sphere will be lowered into the ocean by a single steel cable." "January 30, 1930, off the coast of Bermuda." "The Bathysphere is loaded into the water for a series of unmanned tests." "TheysenttheBathysphere down to 1,500 feet empty and brought it back up." "And when they brought it back up, Beebe could see that there was water inside." "The Bathysphere had leaked, and water had come in under pressure." "So, Beebe knocked the wing nut and as it clears the threads, the pressure inside fires it 40 feet across." "That was how much pressure there was." "What that test showed them was exactly what they would feel if they were on the inside and the water was coming the other way." "After4 yearsof tests, including a successful manned dive to 803 feet in June 1930," "Beebe and Barton work out the kinks in their design." "They are ready to make history." "A manned dive over 1/2 mile deep." "Weoftenthinkaboutrescues in space, but this was even more risky because there was no way that anybody was going to pull the Bathysphere up if the winch let go." "In1934,no humanhas ever explored the deepest 3 pressure zones in the ocean, each deadlier than the last." "On August 21, off the coast of" "Bermuda, 2 men are about to explore zone 3, or the bathypelagic, for the first time." "Pressurewastheenemy." "They were talking about going to 1/2 mile, at which point the pressure per square inch on every inch of the surface of the" "Bathysphere was going to be about 1,000 pounds." "If there was even the slightest leak, you would never know what hit you." "Towithstandsuchpressure," "Beebe and Barton are relying on the spherical design of their vessel to keep them safe." "Asphereis idealasa  structural shape in the sense that it distributes the stresses evenly within the sort of surface, uh, of the structure." "It'slikethekeystoneinan  arch." "A bridge can take an awful lot of weight." "How does it do it?" "It's a rigid block and it transfers the force from here out there." "Well, if you do this in 3 dimensions, then you could have force equally all around it, you end up with a sphere." "Minutesintothedive,they  pass their previous world record, 803 feet." "Asyoukeepgoingdeeper,it slowly begins to get darker." "It becomes a world of shapes, forms, silhouettes, and shadow." "Butastheydescendedbeyond sunlight, they began to see animals that no one had ever seen alive before." "Thesecreaturesarestrangely insubstantial, far different from terrestrial animals." "Mostsuccessfuldeepsea  animals are all fluid." "They have, uh, no gas spaces in their body." "Over1 /2miledown,at3,028 feet, both the Bathysphere and the cable miraculously hold." "It'sstillincredibletome that they were lowered at the end of this cable in water that was much, much deeper than their" "Bathysphere was capable of withstanding." "Whenthehatchiseventually unbolted back onboard the ship," "Beebe and Barton emerge as international celebrities." "TheBathyspherewasfront page news." "William Beebe was a rock star and scientists didn't particularly care for him." "Foryears,mainstream academia remained skeptical about Beebe and Barton's account of animal life in the deep." "Hedidn'thaveany pictures." "He didn't have any samples that he was able to collect." "Buttheirdaringdivewill  inspire a new breed of deep water explorers obsessed with reaching even further." "Beneath the bathypelagic zone lies an even deadlier region." "Zone 4, the abyss, or abyssopelagic zone." "It begins over 2 miles below the surface and stretches all the way down to the vast abyssal plains that make up more than" "1/2 of the earth's surface." "Wehavemappedlessthan 1% of the deep ocean of our planet!" "Mapping is one thing." "Understanding what's on the bottom is another." "And so, that's why we're still in a phase of massive ocean exploration." "ABE,orAutonomousBenthic" "Explorer, is the brainchild of scientists at the Woods Hole" "Oceanographic Institute." "Its mission?" "To map the ocean floor autonomously." "Until 1995, the only way to explore 2 miles down are with manned submersibles or tethered robots, aremotelyoperatedvehicle can stay down a lot longer than" "I can in the submersible and they can launch and recover in higher sea states than I can risk in a human-occupied vehicle." "Buta fullyautonomousrobot might be able to go deeper and stay longer than one with a crew or a tether." "Woods Hole designers come up with a shape that will withstand" "20,000 feet of pressure, a force equal to 4 tons, or 1 adult bull elephant pressing down on every square inch of the human body." "Andweenvisionedasort ofa gumdrop-shaped thing with a gripper on the bottom and little thrusters which could move around sort of like the starship" ""Enterprise."" "Buoyancyisoneofthe greatest challenges in designing any submersible." "These4 beamswereusedfor navigation to..." "Thecraftwillneedair pockets to help it float back to the surface." "But pockets of air are easily crushed." "Howtoholdout the water pressure and still have something which is neutrally buoyant?" "ABE'sdesignersdecideon hollow spheres made out of a surprising material." "Glassspheresaboutthisbig and it has about, oh, 3/4," "5/8-inch wall, and it'll go to the bottom of the ocean." "Most of the time." "ABEisaresoundingsuccess." "Whenthescientistssaw this map come out of the printer in the ship, they said, "look at this." "Do you realize what this tells us?"" "And they said, "do this again."" "Overthenext15years,ABE reveals areas of our planet that otherwise would be total mysteries." "ABE's 222d dive." "9,800 feet down to a volcanically-active section of the ocean floor." "In the control room on the support ship, ABE seems to be performing flawlessly, then..." "Suddenly,justafter midnight, all signals from ABE stopped." "Thesignaljuststopped." "Just stopped." "Dead silence." "Nothing." "Almost2 milesdown,inthe abyssopelagic, the fourth of 5 deadly ocean pressure zones, a million-dollar autonomous robot named ABE mysteriously vanishes." "Wesattherefor hourslike  an Apollo recovery mission trying to figure out what happened, what had gone wrong, what we could do to communicate with it." "Lead engineer Tim Shank believes the robot finally succumbed to pressure." "Ithas6glassballsaround the top of it." "These are glass spheres that give it buoyancy." "One of the balls, weakened after so many dives, imploded." "Whenoneof thesespheres implodes, it's about 5 sticks of dynamite, and so, think of what that's gonna do to the sphere right next to it, which is close to its crush depth, and the one" "next to it." "Inthewakeofa catastrophic implosion, there would be little left of the robot on the ocean floor." "In 15 years of operation, ABE is able to map barely 2/1000ths of" "1% of the ocean floor." "But even if it had survived, it was not built to withstand the deepest and most lethal pressure region in the underwater universe." "Zone 5, the hadalpelagic." "In this endless night, the temperature is just above freezing and the pressure is an incredible 8 tons per square inch, the weight of a bulldozer sitting on every square inch of the human body." "The hadalpelagic zone consists of steep trenches plunging miles beneath the abyssal plains of the ocean floor." "These canyons are cracks in the earth between tectonic plates." "Theoldestseafloorthatwe have on earth is associated with these trench regions where one plate's going underneath another plate." "Only2 men,AmericanNavy" "Officer Don Walsh and Swiss" "Engineer Jacques Picard have ever attempted to explore the deepest Hadal trench." "They named their vessel" ""Trieste."" ""Trieste"iswhat'sreferred to as a bathyscaphe." "Unlike the Bathysphere, which is lowered at the end of a steel-reinforced cable, the bathyscaphe actually descends freely from the surface vessel and it's similar to a balloon." ""Trieste"'stiny61 / 2-foot steel sphere is attached to a massive 50-foot balloon-like tank filled with gasoline for buoyancy." "Wetestedit ." "We made one shallow dive in the harbor, at it was very tight, and then we made the 24,000-foot dive and it worked just fine and so, we were ready for the deep dive." "Themorningof January23,  1960, the bathyscaphe is lowered in the water and begins the descent." "Onthewaydownofthedeep dive, it, uh, ran very much according to plan." "But we got to 20,000 feet, there was this huge bang." "[Bang]" "And we looked around and we couldn't see anything obviously wrong." "Of course, if the pressure hull had failed, we'd probably have been dead before we heard the noise." "Convincedthatthestructural integrity of the sphere hasn't been compromised, they carry on." "Soon, their lights illuminate a flat, muddy bottom." "There, they see something unexpected." "Wesawaflatfish like a small Halibut." "That was important because, uh, a flat fish lives on the sea floor, so, if you see one, there's more than one." "So, that meant there was marine life all the way into the deepest place in the ocean." "Onlyaftersurfacingcould they realize the danger they were in." "Icouldseethishairline crack on the back of the entrance tube." "Tothisday,over50years  later, there have been no more manned dives to such depths." "It's considered too risky." "But scientists at the Woods Hole" "Oceanographic Institute believe their brand-new deep diving craft "Nereus" can survive the trip." "Oneofthegreatchallenges of building a vehicle like" ""Nereus" is to have it withstand, uh, the crushing pressures that exist nearly 7 miles down in the ocean." "UnlikeABE's6glassspheres," ""Nereus" uses over 1,500 smaller spheres made of far stronger ceramic." "6 hours after splashing into the water, "Nereus" reaches the bottom of the trench." "AndMay31 ,2009wehitthe challenger deep in the deepest part and it was, uh, it was--everybody took a collective deep breath." "Soon," Nereus"isofferinga rare glimpse into an alien world." "Itwasathrilltome to see the fauna on the bottom." "We saw about 14 species." "We saw stalked anemones I've never seen before." "You're gonna have to expect those never-seen-before moments when you're down there in an area that's--it's never been observed." "Thetrenchflooralsoreveals hot water vents, home to creatures that may provide hints at the earliest life forms on" "Earth." "Theyliveoffchemicalsthat  come spewing forth out of the deep sea floor." "It's laden with sulfide and methane and other nasty things that would kill humans, but they thrive there." "Thesecreaturesgive biologists pause." "If animals can adapt to such extreme conditions, then life might exist almost anywhere." "Even other planets." "It'sanevolutionary biologist's dream to be able to look at something so intimately related here on earth that may have an impact on how we understand or look for life on other planets." "Scientistsusing sophisticated robots like" ""Nereus" have only glimpsed into the mysterious depths of the underwater universe." "Themorewe explore,the more we discover and the more we realize how little we actually do know." "Despitethecrushingpowerof water pressure, humans will continue to explore Earth's final and deadliest frontier." "Peopledounderstandspace exploration because they could look up every night and see it." "They don't see the deep ocean." "They don't see the vast amount of deep ocean." "They don't realize how much of their life depends on the ocean." "Pressureissuchapervasive, all-encompassing, overwhelming, unforgiving entity." "It's a tremendous natural force." "It's there and you have to deal with it." " sync, corrected by elderman "