Eighteen miles southwest of Nassau, the Johnson Sea Link prepares to dive. Its destination: the floor of the Atlantic Ocean, half a mile below the surface.
To find out firsthand what the black bottom of the sea is really like, CBS News Correspondent Dan Rather made several dives with pilot Tim Askew to view the deep-sea world the way marine scientists do.
It takes almost an hour to reach the sea floor. While they descend, a sphere five inches thick protects them from pressure that will exceed a million pounds per square inch.
As they travel down, the craft actually shrinks. Squeezed by the external pressure, it actually reduces in size by about three-eighths of an inch when it reaches a depth of 3,000 feet.
If the craft were to develop a leak, say a small pin hole, the water pressure that would come in would be of such force that it would just simply cut right through a human body. At about 500 or 600 feet, sunlight is gone.
Nevertheless, many creatures live down here.
Rather and Askew spy a deep-water lobster, probably only found 2,500 feet down or more. As they dive, they see more and more luminescent animals.
"These are undersea lightning buglike creatures," says Rather. "It's a little like the Times Square of the sea."
Those who study the deep sea are constantly surprised by what they find. "We only know very little about life in the deep sea," says marine scientist David Pawson.
"In any sample that you take of deep sea mud,...you'll probably find that more than 90 percent of the animals it contains are new to science," he says.
Before the submersible was made available for science, this ecosystem was studied by dropping nets over the sides of ships and towing the nets around the sea floor. But nets destroyed delicate gelatinous organisms and missed others entirely. Submersibles allow scientists to collect animals with almost surgical precision.
Scientists know of about 2 million different kinds or species of plants and animals. The deep sea may hold 10 million or more, Pawson says. Scientists hope not only to identify these exotic creatures but to use them to develop wonder drugs and compounds.
At one point, the pair see something that shocks even Askew.
"Holy cow!" Askew exclaims. "It's a siphonofore. The head of the animal is up in the front there, and all that other stuff is just tentacles that are actually pulled in. This one is so big it would probably go out 15 feet when they're fully extended."
The deep-flight vehicle is a high-tech sub. "This machine has no limits," says Graham Hawkes, who invented it. "It's very agile. That gives you the freedom that you get with an aircraft."
Says Hawkes: "You're going to be able to do all kinds of strange maneuvers down there, so it's really ideally adapted to go into all the future exploration that lies ahead."
The three and a half hour mission is over quickly"At these depths, your mind is concentrated on what you see right in front of you and the time goes quickly," Rather says. Before they surface, Askew allows Rather to pilot the craft.
The return to the surface is a shock. It is a different world.
"Did I feel more like Alice in Wonderland, Christopher Columbus or Neil Armstrong?" Rather asks himself. "Perhaps more like Alice in a watery wonderland."