The Mariana Trench Is So Deep the Everest Would Vanish Inside It

Introduction: a chasm that defies comprehension

An extreme point on the planet

Did you know that the deepest known point in the world's oceans lies in the Mariana Trench, in the western Pacific Ocean? This spot, called Challenger Deep, reaches a depth of roughly 10,935 meters below the surface of the water, a figure so staggering that it exceeds the imagination of most people who have never had the chance to picture it concretely on a human scale.

To grasp the sheer scale involved, it helps to compare this depth to the height of the planet's tallest peak: Mount Everest, which rises to 8,849 meters above sea level. If Everest were dropped whole into the Challenger Deep, its summit would still sit under more than 2,000 meters of water, a fact that dramatically illustrates just how immense this ocean trench truly is.

An extreme geography still poorly known to the public

The Mariana Trench stretches nearly 2,550 kilometers across the western Pacific Ocean, near the Mariana Islands, not far from Guam. It results from the subduction of the Pacific tectonic plate beneath the Mariana plate, a slow geological process that has shaped this underwater landscape, among the most extreme on the entire planet, over millions of years.

Despite its scale and scientific importance, this trench remains largely unknown to the general public, overshadowed in the collective imagination by far more visible land summits like Everest, even though the depth gap separating the bottom of this trench from the ocean's surface far exceeds the height of the tallest mountain in the entire world.

The rare human explorations of the Challenger Deep

The bathyscaphe Trieste, a pioneer in 1960

The first confirmed human descent to the bottom of the Challenger Deep dates back to 1960, when the bathyscaphe Trieste, piloted by Jacques Piccard and Don Walsh, reached the floor of the trench after a long and perilous descent through increasingly dark and cold layers of water. This technical feat, achieved at a time when underwater technology remained rudimentary compared to today's standards, marked a turning point in the history of global ocean exploration.

For more than half a century after this historic first descent, no other human being returned to this extreme depth, as the priority of space and oceanographic agencies had long been given to exploring outer space rather than Earth's own abyssal depths, a paradoxical situation frequently pointed out by oceanographers themselves over the following decades.

James Cameron and the return of deep-sea exploration

It was not until 2012 that Canadian filmmaker James Cameron, known for his blockbuster films, made a solo descent to the bottom of the Challenger Deep aboard his submersible Deepsea Challenger, reigniting public interest in exploring extreme ocean depths after decades of relative media indifference toward this kind of scientific expedition.

This widely publicized expedition made it possible to gather valuable images and scientific data about this extreme environment, while also demonstrating that modern technology now allowed for safer and more productive explorations than those carried out half a century earlier with far more limited technical means.

Victor Vescovo and the Five Deeps project

An explorer racking up depth records

Between 2019 and 2020, American explorer and businessman Victor Vescovo made several descents to the bottom of the Challenger Deep as part of his ambitious Five Deeps Expedition, which aimed to reach the deepest point of each of the planet's five oceans aboard a single submersible specially built for these extreme missions.

Unlike previous expeditions, generally unique and exceptional events, Vescovo made repeated descents to this extreme depth, allowing for the collection of far more data than isolated attempts in the past, while also testing the reliability of his submersible, the Limiting Factor, through repeated dives in some of the most hostile conditions on the planet.

Surprising discoveries despite extreme pressure

These repeated expeditions made it possible to document unexpected life forms at the bottom of this trench, despite crushing pressure exceeding a thousand times the usual atmospheric pressure felt at the surface, once again demonstrating the remarkable adaptability of living organisms in the face of environmental conditions that seem, at first glance, entirely incompatible with any form of biological existence.

The data collected by these successive missions continues to feed scientific research on abyssal ecosystems, a field still largely unexplored despite its importance for understanding the limits of life on Earth and, potentially, elsewhere in the universe, on icy moons that orbit certain planets in our solar system.

Understanding the geological formation of this extreme trench

The mechanism of tectonic subduction

The Mariana Trench results from a geological process called subduction, in which the denser Pacific tectonic plate slowly slides beneath the Mariana plate, creating an underwater depression whose depth increases gradually over millions of years thanks to this continuous tectonic movement, particularly active in this region of the globe.

This type of tectonic boundary, called a subduction zone, is also responsible for numerous earthquakes and volcanic eruptions in the region, with the Pacific Ring of Fire concentrating a large share of the world's seismic and volcanic activity due to the presence of multiple zones of this type all around this ocean.

Pressure and darkness that are almost unimaginable

At the bottom of the Challenger Deep, pressure reaches roughly 1,086 bars, or more than a thousand times the standard atmospheric pressure measured at sea level, a force capable of instantly crushing most structures and organisms not specifically adapted to such an extreme environment, hostile to any non-specialized life.

At this depth, sunlight no longer penetrates at all, plunging this environment into total, permanent darkness, while the water temperature hovers just a few degrees above freezing, conditions that make the documented presence of life during the various successive expeditions to this region of the globe all the more remarkable.

Why this comparison with Everest is so fascinating

A mental image accessible to everyone

The comparison between the depth of the Challenger Deep and the height of Everest works so well with the general public because it turns an abstract number, hard to picture mentally, into a concrete image that is immediately understandable by anyone, regardless of their prior scientific knowledge of geography or oceanography.

This popularization technique, widely used by ocean agencies like the American NOAA, effectively conveys the true scale of ocean depths to a public that would otherwise likely struggle to concretely grasp what a figure as staggering as ten thousand meters below the surface of the water actually means.

A reminder of our persistent ignorance of the seafloor

This comparison also highlights an often overlooked fact: the ocean floor of our own planet remains, even today, less well mapped than the surface of the Moon or Mars, despite the considerable technological progress made over recent decades in the combined fields of space and underwater exploration.

This paradoxical situation shows just how much the exploration of Earth's own abyssal depths remains an underfunded scientific field compared to space exploration, even though these extreme environments could hold valuable clues about the origins of life and the possibility of extraterrestrial life existing under similar conditions elsewhere in our solar system.

What this discovery teaches us about the limits of exploration

Technologies still constantly evolving

Submersibles capable of reaching such depths remain extremely rare and expensive to build, requiring materials able to withstand crushing pressure while protecting the occupants or the onboard scientific instruments, an engineering challenge that continues to limit the number of possible expeditions to these extreme zones each year around the world.

The progress made from the Trieste to Victor Vescovo's Limiting Factor nonetheless reflects significant technological evolution, which raises hopes for more frequent and more productive future explorations, capable of documenting even further the biodiversity and geology unique to these largely unknown extreme environments.

A call to continue ocean exploration

Scientists involved in studying the Challenger Deep regularly stress the need to continue and intensify the exploration of the ocean floor, which could reveal valuable information about climate, marine biodiversity, and even the origin of life on Earth, fundamental questions that go well beyond the simple depth record associated with this particular trench.

This trench thus continues to represent a powerful symbol of the current limits of human knowledge, reminding us that even on our own planet, entire territories remain largely unexplored and likely to hold many more surprises for future generations of passionate researchers and explorers.

Conclusion: a humbling reminder of the ocean's immensity

A lesson in proportions

The comparison between the Challenger Deep and Everest offers far more than a simple statistical curiosity: it forcefully reminds us just how much the oceans remain largely unknown territories, capable of containing underwater landforms that exceed in scale the tallest peaks on the entire planet.

A territory still largely to be explored

While humanity keeps turning its gaze toward space, the Mariana Trench is a reminder that equally fascinating mysteries still await discovery much closer to home, in the depths of our own oceans, a territory that will likely continue to surprise researchers for many generations to come. Every new expedition, whether led by government agencies or by private explorers like Victor Vescovo, helps close a little more of the immense gaps that still remain in our knowledge of the world's ocean floors.

Ultimately, the Challenger Deep is not just a depth record: it embodies a powerful symbol of everything still left to discover on our own planet, at a time when one might otherwise believe that nearly the entire surface of the Earth has already been mapped and understood down to its smallest details by modern science.

For now, only a handful of people on Earth can say they have personally witnessed the bottom of the Challenger Deep, a club smaller than the group of astronauts who have walked on the Moon. That imbalance alone says something about where humanity has chosen to direct its curiosity and its funding over the past sixty years, and it leaves open an enormous amount of scientific ground still waiting for the next generation of explorers willing to look down instead of up.

By Maxime Marquette, columnist

Sources

Primary sources

NOAA — National Oceanic and Atmospheric Administration of the United States

NOAA Ocean Exploration — data on abyssal explorations

Nausicaá — the Mariana Trench, 11,000 meters below the sea

Secondary sources

National Geographic France — environment and ocean exploration

Futura Sciences — news on earth sciences

Sciences et Avenir — scientific analysis on the oceans