#516 | Journey to the Deep: A Short History of Underwater Exploration
English Learning for Curious Minds
Deep Dive
What was Ferdinand Magellan's method for measuring ocean depth in 1521?
Ferdinand Magellan measured ocean depth by attaching a cannonball to a long rope and lowering it off the side of his boat. When the rope went slack, it indicated the cannonball had hit the bottom. However, after lowering it 732 meters, the rope remained tight, leading Magellan to conclude the ocean was 'immeasurably deep.'
What was the significance of Guglielmo de Lorena's diving bell invention?
Guglielmo de Lorena's diving bell, invented in the 16th century, allowed divers to explore underwater for extended periods. It was used to recover treasures from ancient Roman barges at the bottom of Lake Nemi, marking one of the first instances of underwater archaeology. The device was a wooden barrel with a crystal window and a system to pump fresh air, enabling divers to withstand cold and fatigue rather than running out of air.
What was the purpose of David Bushnell's 'Turtle' submarine during the American War of Independence?
David Bushnell's 'Turtle' was a small, self-powered submarine designed for military use during the American War of Independence. Its objective was to stealthily approach British ships, attach a bomb to their hulls, and escape before detonation. However, strong currents and limited air supply prevented it from completing any successful missions.
What major scientific discoveries were made by the HMS Challenger expedition?
The HMS Challenger expedition (1872-1876) discovered around 4,700 new species of marine life and identified the Mariana Trench as the deepest part of the ocean. It measured ocean depths, collected samples, and studied marine biology, proving that the deep sea was not inhospitable but teeming with life. This expedition laid the foundation for modern oceanography.
What challenges did Don Walsh and Jacques Piccard face during their 1960 descent into the Mariana Trench?
Don Walsh and Jacques Piccard faced extreme pressure during their 1960 descent into the Mariana Trench, reaching a depth of 10,984 meters. The pressure at this depth was over 1,000 times that at sea level, equivalent to 1,250 kilograms pushing down on every square centimeter of their bathyscaphe. Their reinforced steel craft, with walls 9cm thick, was essential to withstand the crushing pressure and ensure their survival.
How does the number of manned descents to the Mariana Trench compare to Mount Everest summits?
As of a few years ago, there have been only 22 manned descents to the Mariana Trench, compared to thousands of Mount Everest summits. The extreme difficulty, expense, and technological challenges of deep-sea exploration make it far less accessible than climbing Everest, despite both being iconic feats of human exploration.
- Early diving attempts were limited by pressure and air supply.
- Guglielmo de Lorena's diving bell allowed for underwater exploration of shipwrecks.
- Cornelis Drebbel's submarine, though not initially successful militarily, represented a significant technological advancement.