As midnight neared, we bobbed around in the black Caribbean Sea aboard a rubber dinghy. There were five of us out there, peering down into the undulating, forever darkness. We scoured the water for signs of a telltale light, coming from below.

A yellow submarine — the same one that seven years previous captured the first deep sea footage of a giant squid — was expected to return to the surface after spending five hours in the ocean depths off of Eluethera, a snake-shaped island in The Bahamas.

“There!” yelled a crewmember, pointing 50 feet off the dinghy. And there the water began to glow, an emerald radiance amid the black sea. The shine grew brighter and brighter until the submersible’s bubble-like capsule, holding three humans, popped out of the water. On cue, a crewmember balanced on the edge of the dinghy, lunged into the water and swam over to the exploration craft, preparing to hook it to a looming 184-foot vessel called the Alucia, which would soon hoist the yellow submarine from the sea, and end the night’s mission.

Earth’s deep sea is famously uncharted, and on this August night the exploration group OceanX(opens in a new tab) sought out sixgill sharks — the dominant shark of the dark fathoms(opens in a new tab) — at depths of 3,000 feet. The surface of the moon is better mapped(opens in a new tab) than these lightless realms, a place where sealife awaits dead, sinking creatures for their meals. 

Without a submersible, most people can’t ever glimpse these profoundly remote, inaccessible places. So OceanX — a privately funded endeavor which has dived in Antarctica, the Galapagos, and beyond — brings tales of the deep back to the surface world. Each dive is carefully planned and the craft meticulously inspected and loaded with oxygen before seasoned submariners track every second of the expedition in a mission control room. 

In many ways, these marine ventures into the dark feel like a NASA endeavor to a new world(opens in a new tab), billions of miles away.

“Down here you’re just looking for weird things — and seeing if that weird thing has a name yet,” Edd Brooks, a marine ecologist, told me at a depth of 2,500 feet that morning.

We had dropped into a canyon, so the sub’s pilot inched warily forward. Even with the radiant spotlight, we could only see 20 or so feet ahead. There were lines on the white lunar-like ground, where creatures had once crept and slithered along the ground. But like the moon, there was nothing to blow their tracks away.

A giant, knife-shaped spire appeared ahead, and we approached. A colony packed with sponges, corals, and spiky critters clung there. Brooks squinted and brought his nose to the glass.

I asked what this place was.

“No one’s ever seen this before,” he said.

Just as the clock struck midnight on New Year’s Day 2019, hundreds of astrophysicists, engineers, and astronomers gulped champagne from plastic cups and cheered in an auditorium at the Johns Hopkins Applied Physics Laboratory, in Columbus, Maryland. The famed Queen guitarist Brian May — who also happens to be an accomplished astronomer(opens in a new tab) with vivacious, curly gray hair — stood in front of everyone, cheering too.

It was certainly unusual for everyone to be here, partying, but they had good reason to celebrate. In just 33 minutes, a legendary NASA spacecraft, New Horizons (which is navigated by Johns Hopkins’ scientists), was expected to swoop by a mysterious, ancient object, 1 billion miles past Pluto. It would be the farthest world ever visited by an exploration craft — and by extension — humanity.

Pictures of the weird, red snowman-shaped world(opens in a new tab) came back to Earth days later, after streaming some 4 billion miles through the solar system. People had never laid eyes on such a world before — a place frozen in time from our early solar system, a place where scientists could peer into a relic of our wild cosmic past, preserved in the coldest parts of space.

But here on Earth, OceanX did something similar, nearly 3,000 feet under the ocean. In 2013, marine biologist Edie Widder, sitting inside the yellow submarine, used a flashing light to attract a giant squid(opens in a new tab) — a creature of ancient sealore — to the submersible. They filmed the creature as its mighty purple tentacles lashed out at the light, before the enigmatic monster darted back into the shadowy water, whence it came.

“That was considered the holy grail of natural history photography,” said Widder.

Years later, Widder, a renowned biologist, again found herself on the OceanX’s mothership, the Alucia. Sitting in the dining area, where the tables and chairs are bolted to the floor in case of rocking waves, Widder yearned for more deep sea exploration. At 67 years old — and after decades of watching the degradation of marine environments(opens in a new tab) “with increasing dismay” — Widder lamented humanity’s still relatively large ignorance of the sea. She pondered why the U.S. maintains the expensive International Space Station, but doesn’t have an aircraft carrier-sized ocean exploration vessel.

The ocean isn’t just an alien realm. It controls the planet. Its whims bring decades-long shifts in climate(opens in a new tab), and it absorbs over 90 percent(opens in a new tab) of Earth’s accumulating heat, from global warming. It’s changing as it grows increasingly acidic(opens in a new tab). It’s a world we need to understand.

Each day, notes Widder, the largest migration on Earth occurs in the sea, as critters travel from deep to shallow waters, and back again. And among these critters are trillions of organisms that glow(opens in a new tab) as they fall to the seafloor, a phenomenon known as “marine snow.” She wants to know why some of it glows, and why some of it doesn’t. She wants to know what role it plays in trapping carbon in the deep sea, and moderating Earth’s climate. She wants to know all about the ocean’s secret, glowing world.

“This is a major part our planet — and we don’t even know how it works,” Widder said.

When submersibles, like those on the Alucia, do explore the sea, finding the unexpected is expected. Photographers diving in the yellow submarine have stumbled upon bizarre, alien creatures — dancing upon the seafloor on silken legs(opens in a new tab) — that defy scientific explanation.

Vincent Pieribone, a Yale University neuroscientist who directs the OceanX science missions, seeks more of the unexpected. The more unusual, the better, he said, as we descended on a dive into the pitch black, with small translucent, gelatinous critters fluttering against the sub’s bubble.

Like an eager Ian Malcom, Jeff Goldblum’s character in the Jurassic Park franchise, overcome with theories and sparks of thought, Pieribone believes there’s more strange stuff out there, hiding in places humanity has yet to visit. He cites the coelacanth — a huge fish thought dead for 65 million years(opens in a new tab) — around when the dinosaurs went extinct. But that changed in 1939.

“It showed up in a fish market in Indonesia,” said Pieribone.

“What is out there, is the question,” he pondered, as we peered into the black.

Aboard the Alucia, the thrill of witnessing the unknown always lies in the shadow of the primary mission: bringing everyone back up to the surface.

These are all crewed missions — not robotic explorers.

“Nobody loses sleep when you lose a robot,” said Pieribone.

OceanX has made thousands of deep sea dives. But it’s always a careful operation. The Alucia’s captain, Peter Fielding, doesn’t sleep until the sub is safely aboard. There’s a lot that can go wrong leagues under the sea, if you’re not careful.

“Your vessel needs to resist that pressure,” said Pieribone, as we hovered over the seafloor. “Every seal, every wire.”

Then, there’s the problem of communicating with the surface. When Neil Armstrong stepped foot onto the chalky lunar ground in 1969, he spoke to Earth from 250,000 miles away using a radio. But radios are useless in the deep sea, just like GPS and cellphones.

“Navigation and communication can be a complete nightmare,” said Pieribone. So they communicate the same way whales do — by sending sounds through the water, also known as sonar. While the sub is seeking new realms, massive squids, and glowing life, veteran submariners aboard the Alucia listen for the sub’s activity in a chilly, air-conditioned control room decorated with monitors and digital maps.

There’s a rule: No one ever veers from the mission plan.

“You make the plan, you dive the plan,” Alan Scott, an OceanX sub expert who spent 23 years doing undersea bomb disposal for the UK Navy, and another eight with the Navy’s submarine rescue team, said.

These submarines are safe, but “it’s not for everyone,” Scott acknowledged.

Perhaps the greatest endorsement of the submersible’s reliability comes from the maker himself, Patrick Lahey, the creator of Triton Submarines. The subs aren’t released into the wild until he actually takes them to depth.

“I dive in every one of the subs we build,” said Lahey, who said he’s made tens of thousands of dives. The subs endure an incalculable number of tests, and each craft is scrutinized by regulators.

“When the paperwork weighs as much as the submarine, you know you’re done,” said Lahey.

The OceanX submersibles are built to make thousands of dives. Like NASA’s now-retired Space Shuttles, they incur extreme environments, but are designed to be used repeatedly in some of the most extreme places humans can go.

“To me, they really are spaceships,” said Lahey.

The good news about ocean exploration is that there’s more of it happening.

Today, there’s the National Oceanic and Atmospheric Administration’s (NOAA) vessels, which explored Earth’s deepest point, the Mariana Trench, in 2016. This year the Ocean Exploration Trust — who are private exploration researchers — banded with NASA(opens in a new tab) to hunt down a valuable collection of meteorites that had exploded over the Pacific Ocean. Then there’s the Schmidt Ocean Institute, which employs a fleet of robots, or remote operated vehicles (ROVs), to scour the deep sea. And, there’s certainly others.

“More assets are being put into exploration now than possibly ever before — which is wonderful,” said Katy Croff Bell, a deep sea scientist who heads the MIT Media Lab’s Open Ocean Initiative — which seeks to connect people to the oceans.

But there’s a problem. Although it’s sometimes easy to forget, Earth is an ocean world, and we’re outmatched by the vastness of the seas.

We can drop cameras into the water and press record — but who can watch hundreds and hundreds of hours of film, attempting to glimpse some undiscovered terrain or a new creature?

“The way we do it now is kind of bonkers,” said Bell, who is working with scientists at the Monterey Bay Aquarium Research Institute to develop smart programs that can recognize “interesting events.”

But OceanX will continue to depend on human eyes to seek out the underwater realms, which Pieribone said a robot’s camera might miss, or not understand. Having scientists like Widder aboard to seek out elusive sea creatures, and bring the film back to surface, has already proven invaluable.

And this might be a way to ignite more interest in the oceans — a world that often gets eclipsed by the realm beyond our atmosphere. NASA is expected to get around $19.6 billion(opens in a new tab) in total for its 2019 budget. More than half of this goes to space exploration. Meanwhile, NOAA’s ocean exploration budget request for 2018 was $19.4 million(opens in a new tab).

Space, with its vivid galaxies, enigmatic black holes, and new worlds, after all, gets tremendous PR. “There’s this sense of awe and discovery,” said Bell. “And a lot of the ocean stories you hear are death and destruction and the corals are dying.”

“In a certain way it may just turn people off,” added Bell. “How can we change that story?”

Descending into the unknown, in a yellow submarine, is the OceanX answer.

“Most of the ocean is below us,” said Pieribone at 1,000 feet of depth, as the last of the sunlight dimmed, and our bubble turned dark.