Life in a World Beneath the Light

By: G. Maranhão 

Over four centuries ago, Galileo Galilei became the first in human history to observe Mars through a telescope. Since then, generations of scientists have dedicated themselves to mapping every square inch of the Red Planet, and today, we’ve charted virtually 100% of its surface. Now, to put that into perspective, that means we have a 72.7% more complete and clearer picture of Mars’s surface than we do of the ocean floors that surround us. Despite covering an approximate 70% of Earth’s surface, the sea remains one of humanity’s most paramount mysteries. In over 300,000 years of human existence, we’ve explored only around 20% of our oceans.

The sea is the most fascinating aspect of our planet, likely where all life originated, four billion years ago. It is a world that remains largely invisible and hidden from us. Since we cannot understand it, we create myths, mysteries, theories; all of which seem pointless when considering the limit of our knowledge. The Bermuda Triangle, a much-debated phenomenon ever since the mid-20th century, has long piqued the public’s attention, with ships, planes, and people said to vanish without a trace. Off the coast of Japan, the Yonaguni Monument, referred to as a real-life Atlantis, continues to divide specialists over whether its staircase-like formations were constructed by an ancient civilization, or are simply the result of natural erosion. Moreover, when scientists discover new species, from the Apolemia - a jellyfish-like organism stretching 47 meters - to fish that generate their own light deep within the Abyssal Zone, the ocean still continues to defy expectations and logic. Every discovery only underscores how little we truly understand the world we inhabit.

​But while many of these mysteries remain unsolved, a new discovery has revealed something even more extraordinarily unexpected - and yet, entirely real. At the bottom of the Kuril-Kamchatka Trench (near the Hokkaido region), 10,542 meters below the surface of the Pacific Ocean, where no sunlight could ever reach, a team of Chinese researchers found life thriving in conditions once thought impossible. Even compared to Mount Everest, the tallest mountain on Earth, this point sits 1,693 meters above its peak - the equivalent of two Burj Khalifas stacked on top of each other.

​The researchers entered the trench using a submersible, expecting lifeless and stark results. However, they were inexplicably met with foot-long tube worms, molluscs, crustaceans, sea cucumbers, among others; an entire functioning ecosystem. For decades, biologists largely believed that only microscopic organisms could withstand such extreme pressure (around 106 MPa) and the complete absence of sunlight. This discovery, published in Nature in 2025, disproves that assumption - showing that rich, complex life can exist even in the deepest, darkest corners of our planet.

Even without photosynthesis, through chemosynthesis, a process in which bacteria create energy from chemicals such as methane and hydrogen sulfide leaking from cracks in the ocean floor, these organisms form the foundation of an entire food web that operates without any reliance on sunlight. It’s a self-contained system, powered not by sunlight, but by the Earth itself. This discovery also raises the possibility that similar or completely new ecosystems could exist in other deep-sea trenches - or even on other planets and moons with hidden oceans beneath their surfaces.

The Hadal Zone - depths below 6,000 meters - has always been an alien world, a part of our planet that remains largely unexplored and unknowable. Now that technology has made it possible for us to reach these extreme depths, something cannot be overstated: from the dark Abyssal Zone to the strange and unexplained phenomena near the surface, the ocean is a memorandum that the unknown is still present in our own world, not only in faraway galaxies. Each new dive reveals how little we know - and how much remains out there, waiting to be discovered. What lies beneath the light may not only contain the secrets of our planet's past, but also a key to possibilities we've not yet imagined.