There is a place on Earth so deep, so dark, and so hostile that it might as well be another planet. It is deeper than Mount Everest is tall. The pressure at its bottom is equivalent to having fifty jumbo jets stacked on top of your body. Sunlight has never touched its floor. And yet, life exists there—strange, alien, and utterly fascinating. This is the Mariana Trench. And in this episode, we descend into its secrets. We begin with the sheer scale of the abyss. The trench stretches over 1,500 miles across the western Pacific, a crescent-shaped scar in the ocean floor where the Pacific Plate is being forced beneath the Philippine Plate in a process called subduction. At its southern end lies the Challenger Deep—the lowest point on the surface of the Earth. How deep? Estimates vary, but the most recent measurements place it at nearly 11,000 meters—roughly 6.8 miles down. If you dropped Mount Everest into the Challenger Deep, its peak would still be more than a mile underwater. Only a handful of humans have ever made the journey. In 1960, Jacques Piccard and Don Walsh descended in the bathyscaphe Trieste, spending twenty minutes at the bottom before a cracked window forced them to surface. It would be another fifty-two years before anyone returned. In 2012, filmmaker James Cameron made a solo dive in the Deepsea Challenger, reaching a depth of nearly 11,000 meters and spending hours exploring the alien landscape. And between 2019 and 2022, investor-adventurer Victor Vescovo visited the Challenger Deep a record fifteen times, bringing the total number of humans who have ever been there to just twenty-two. But the trench is not a dead zone. It is teeming with life—life that has evolved to survive conditions that would kill anything from the surface. In 2021, Chinese scientists aboard the submersible Fendouzhe conducted 33 dives and discovered over 7,000 new microbial species, nearly 90 percent of which had never been documented before. They found amphipods—shrimp-like crustaceans—that grow to nearly a foot long. They found the hadal snailfish, a small, pink, scaleless fish that holds the record as the deepest-living fish ever discovered, thriving at depths where most creatures would be crushed. And they found xenophyophores—single-celled organisms the size of saucers, living in complete darkness at the bottom of the world. The trench is also a place of mystery. For a decade, scientists were baffled by a strange sound picked up by underwater microphones near the Mariana Trench. They called it the "biotwang"—a low, sonorous moan followed by a squeaky, mechanical echo that sounded, to some, like a Starship Enterprise sound effect. Some speculated it might be an alien species hiding in the deep. In 2024, the mystery was finally solved: the biotwang is the call of the Bryde's whale, a rarely observed baleen whale that frequents the waters near the trench. But the trench is not just a biological wonder. It is a geological engine. The Mariana Trench is part of the Pacific Ring of Fire, a tectonically active region where plates collide, causing earthquakes, volcanic activity, and the formation of hydrothermal vents. These vents spew superheated, chemical-rich fluids from deep within the Earth's crust, creating oases of life in the pitch-black abyss. Chemosynthetic bacteria—organisms that derive energy from chemicals rather than sunlight—form the base of a food web that supports tube worms, mussels, shrimp, and crabs. The Mariana Trench is a reminder of how little we know about our own planet. We have mapped the surface of Mars in greater detail than the floor of our own oceans. We have sent probes to the edges of the solar system while the deepest trenches on Earth remain largely unexplored. Every dive brings new discoveries, new species, new questions. And as we descend into the abyss, we are forced to confront a humbling truth: the most alien place in the universe might be right here, beneath the waves. So close your eyes. Breathe deeply. And let the mysteries of the Mariana Trench carry you into the deepest sleep of your life. This is deepSleep Theory—where the wonders of the unknown become your bedtime story. Become a supporter of this podcast: https://www.spreaker.com/podcast/deepsleep-science--7308176/support. This episode includes AI-generated content.
