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Amazing Planet

Dive Down Into The Ocean's Unexplored Twilight Zone

More people have been on the moon than have visited the region of ocean depth known as the "twilight zone." And maybe that's understandable: a dive down there requires specialized equipment, including bulky, redundant sets of gear in case anything goes wrong. But trips to the twilight zone are inevitably rewarding, with new species always swimming into view.

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Why Is It So Unexplored?

What makes the twilight zone so mysterious is its depth. Between 200 and 500 feet (60 and 150 meters) below the ocean's surface, the zone is too deep for recreational divers but above the depths scientists generally explore in submarines. As a result, it's brimming with undiscovered species. According to Scientific American, those brave enough to take the risk of venturing to this depth can discover new species at a rate of more than 10 per hour. And those species are strange ones: because minimal light gets through the water at these depths, you find sea creatures with bright red hues—since red wavelengths are filtered out of deep water—and coral that has to depend on something other than the sun for energy.

Related: Brine Pools Are Lakes On The Bottom Of The Ocean

The Thrill Of Exploration

New technology is making this once unexplored zone more accessible to researchers. According to Wired, "...these depths historically have been too shallow to justify the expense of sending a sub, yet too deep to pull off safely with scuba gear. That's finally changing: New technology makes it safer for divers to stay submerged as long as seven hours, so now scientists with the requisite funding (and nerves) can explore the deep reefs and see what no human has ever set eyes on." Of course, that doesn't open the area up to people just going for a visit. For regular people, there's an exhibit at the Steinhart Aquarium in San Francisco that showcases the strange scenery that exists in the twilight zone.

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Watch And Learn: Our Favorite Videos About Ocean Exploration

Pressure in the Twilight Zone

Get a glimpse of the animals that exist at this depth.

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Key Facts In This Video

  1. The Twilight Zone is located below normal scuba diving range, but above the range of submersibles. 00:05

  2. Divers in the ocean's Twilight Zone experience pressure about 10 times greater than surface pressure. 01:35

  3. Divers that descend to the Twilight Zone only have 15–20 minutes to perform their work before beginning an ascension that takes multiple hours. 02:44

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