What If You Sank and Couldn't Stop?

You jump off a boat over a coral reef for a swim, and start to sink. You can't swim up. A blue whale rises past you, hammerheads circle you, and the sunlight runs out. You meet a giant squid, an anglerfish, a beaked whale holding its breath, and the Titanic. Then the seafloor ends at a cliff, and you fall into the deepest trench on Earth, onto its floor, and on into the rock beneath it. What is real: every depth on screen and the animals that live there. Red light is gone from the sea within the first few dozen metres, and almost all sunlight by 200 m. Recreational divers stop at 40 m; the deepest scuba dive ever was 332 m. Below 1,000 m no sunlight has ever reached, and about three in four animals make their own light. A Cuvier's beaked whale has been tracked to 2,992 m. The Titanic lies at about 3,800 m. The deepest fish ever filmed was a snailfish at 8,336 m. The bottom of the Challenger Deep is about 10,935 m down, and a plastic bag has been filmed there. The weight on your fingernail is the real water pressure on one square centimetre: about 385 kg at the Titanic and over a tonne at the bottom. What is not real, or not known: nobody could survive this, and these places do not line up in one straight drop (the Titanic is in the Atlantic, the Mariana Trench in the Pacific); the cliff beside the Titanic is invented. Nobody has ever seen a sperm whale fight a giant squid. Animals are drawn larger and closer than you would meet them, and in the dark they are lit by your torch. Below the seafloor, the layers of rock are the textbook ones, but their exact thickness here, the rock's temperature and the depth of the mantle (about 17.7 km) are estimates. Nobody has ever drilled into the mantle, so the very last thing you see is made up. You watched for nine minutes. The Titanic took two hours and forty minutes to sink. You passed it on your way to somewhere much deeper. CHAPTERS 0:00 The Titanic 0:06 The reef 0:34 A blue whale 1:04 The twilight zone 2:19 The midnight zone 3:48 The Titanic 4:16 Over the edge 5:30 The trench 7:36 The bottom of the ocean HASHTAGS #whatif #science #ocean #titanic #marianatrench