The Mariana Trench is an epic canyon carved out of the floor of the Pacific Ocean. At its deepest, it reaches down nearly 7 miles (about 11 kilometers). That's three times the width of Manhattan in New York City. Mount Everest could stand up in there with plenty of headroom to spare.
Imagine being there in the crushing darkness, a massive weight of water pressing down from above. What do you think it would sound like? Would it be quiet? The US National Oceanic and Atmospheric Administration has the answer. It's surprisingly noisy down there.
A NOAA-funded project lowered a hydrophone (a microphone designed for underwater use) and a sound recorder into Challenger Deep, the deepest trough in the Mariana Trench in July. A team retrieved the hydrophone in November, and NOAA shared some of the deep-sea recordings on Tuesday.
Earthquake as heard in the Mariana Trench
The gadget filled up a flash drive over the course of 23 days. "The ambient sound field is dominated by the sound of earthquakes, both near and far, as well as distinct moans of baleen whales, and the clamor of a category 4 typhoon that just happened to pass overhead," NOAA research oceanographer Robert Dziak said in a statement.
The recordings are haunting. There's the pulsing moans of whales and dolphins, the fuzzy thwacking of a ship propeller and the mesmerizing sounds of a 5.0 magnitude earthquake rumbling from near Guam.
The Mariana Trench represents a frontier for exploration right here on Earth. "Avatar" filmmaker James Cameron is one of the very few people to actually visit the deepest part of the trench. He used a high-tech submersible vehicle to accomplish the feat in 2012.
The audio project is a joint effort between NOAA, Oregon State University and the US Coast Guard. Researchers are curious about how human-made noises, such as the sound of ship propellers, might affect sea life, including fish and whales. These first recordings establish a basic understanding of the noise levels in the trench. An expedition scheduled for 2017 will lower the hydrophone for a longer time. A camera will also go along for the ride.