Located 124 miles east of the Mariana Islands in the Western Pacific is the Mariana Trench — a crescent-shaped scar in the earth’s crust that measures more than 1,500 miles long and 43 miles wide. The distance between the surface of the ocean and the trench’s deepest point — the Challenger Deep — is nearly 7 miles. If Mount Everest were dropped into the Mariana Trench, its peak would still be more than a mile underwater. Because of its extreme depth, the Mariana Trench is cloaked in perpetual darkness and the temperature is just a few degrees above freezing. The water pressure at the bottom of the trench is a crushing 8 tons per square inch — or about a thousand times the standard atmospheric pressure at sea level. Pressure increases with depth. The first and only time humans descended into the Challenger Deep was more than 50 years ago in 1960, when Jacques Piccard and Navy Lt. Don Walsh descended in a Navy submersible called the Trieste. After a 5-hour descent, the pair spent only a scant 20 minutes at the bottom, but were unable to take any photographs due to the clouds of silt stirred up by their passage. The Trieste expedition laid to rest any doubt that life could exist in the Mariana Trench. In fact, the pressure is so great that calcium can’t exist except in solution, so the bones of vertebrates would literally dissolve. So, are there fish that deep? Nobody knows.
