“How deep is the ocean?” has been the tagline for many popular song renditions from Frank Sinatra to Eric Clapton! Variations of gigantic proportions to describe feelings of love and affection have always translated into the depths of the oceans, the height of the skies or the width of the mightiest rivers and valleys.
In reality, the ocean’s depth is a subject that has only emerged as a frontrunner of research and scientific studies in the past couple of centuries. From the time of the ancient Greek historians and scientists till the modern age, it was believed that life could not exist in the deepest depths of the ocean. The beliefs stemmed from the surmise that virtually no light penetrated the deeper layers of the seas and hence life had no chance of existence or survival in the darkest layers of the oceans or the seabed.
That belief was somewhat shattered when in 1875 the British Royal Navy survey ship HMS Challenger tracked the deepest part of the waters in the Pacific Ocean southwest of the island of Guam and discovered a series of trench or underwater valleys in an area near the Mariana Islands that stretched for kilometers along the sea floor. The maximum depth recorded at that time was 8,184 meters (26,850 feet). In the mid 1950s, another research vessel also called the HMS Challenger made fresh attempts for additional measurements in the same area and recorded depths of 10,900 meters using echo sounding. In the 21st century, a study conducted by the University of Hawaii determined a depth of 10,971 meters followed by the United States Center for Coastal & Ocean Mapping which established the depth of the Challenger Deep at 10,994 meters, an astonishing 36,070 feet. To understand this in real terms, let’s look at some simple examples. The Challenger Deep, named after the HMS Challenger, is the deepest part of the ocean.
Human exploration of the Challenger Deep was first conducted in 1960 by Don Walsh and Jacques Piccard. Using the Trieste Bathyscaphe, a vessel designed for research in deep waters they reached a depth of 10,916 meters but their rough landing on the seabed created near invisible conditions for them to see anything in the depths and they could only spend about 20 minutes. In 2009 two separate sonar mapping researches put the depth at 10,971 and 10,902 meters respectively.
In 2012, James Cameron fulfilled his desire of descending to the very bottom of the Challenger Deep in his submersible, Deepsea Challenger spending nearly three hours on the seabed; a feat that was fraught with danger as the pressure of water at those depths is incredibly punishing. Images of that dive revealed abundance of life and never before seen creatures in the deepest waters of the ocean where sunlight does not penetrate at all. It also established the might of the trenches in terms for us to understand better. If Mount Everest, the tallest on earth was placed in this depth, there would still be about a mile of water above its peak to the ocean’s surface! Or it would take over 5 Empire State Buildings from the ocean floor to the surface of the ocean; at 120 times larger than the Grand Canyon, the sheer size and depth of the Mariana Trenches are unimaginable.
The Mariana Trench or the Challenger Deep is located at the convergence of two plates of the Earth’s crust. When the plates push against each other, one plumbs into the ocean depths resulting in deep ocean trenches.