The story
On January 23, 1960, Jacques Piccard, a Swiss engineer, and Don Walsh, a US Navy lieutenant, descended to the bottom of the Challenger Deep in the Mariana Trench in the western Pacific, the deepest known point of Earth's oceans, about 10,900 meters down. Their vessel, the bathyscaphe Trieste, took nearly five hours to descend. They spent about 20 minutes on the seafloor, where the water pressure is over 1,000 times that at the surface, before returning.
The bathyscaphe was the invention of Jacques's father, Auguste Piccard, who in 1931 had ridden a pressurized gondola under a hydrogen balloon into the stratosphere. He applied the same idea in reverse: the crew sat in a small, thick steel sphere hung beneath a large float filled with gasoline, which is lighter than water and barely compressible. Iron pellets served as ballast; dropping them let the craft rise. Trieste was built in Italy and launched in 1953, and the US Navy bought it in 1958.
During the descent, one of the outer windows cracked with a loud bang, but the dive continued. On the bottom, the cloud of silt they stirred up limited what they could see. No human returned to the Challenger Deep until film director James Cameron's solo dive in 2012. The dive proved that people could reach, and safely return from, the full depth of the ocean.
Why it mattered
- Deep-sea submersibles such as Alvin, launched in 1964, built on the bathyscaphe's success.
- The dive helped spur scientific exploration of ocean trenches and later the discovery of life at hydrothermal vents in 1977.
- Debate over whether fish lived at the bottom, as Piccard reported seeing, fed decades of research into life at extreme pressure.
Sources
- Trieste's Deepest Dive U.S. Naval Institute
- Lucky Day: Navy Celebrates 60th Anniversary of Deepest Ocean Dive Office of Naval Research
- Trieste (bathyscaphe) Naval Historical Center
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