Sorry, Trekkies, but space may not, in fact, be the final frontier. Want to take another guess? Here’s a hint: You went there on your last beach vacation. Yes, the ocean is the next unexplored fringe on humanity’s to-discover list. Scientists have identified nearly 2,000 planets orbiting other stars and mapped enough of the moon to spot anything bigger than a pickup truck, but on parts of the ocean floor, they can’t see anything that’s smaller than 15 aircraft carriers laid end to end. That’s the kind of hazy territory Rebecca Carey works in.

”You’re going out to a space no one has ever seen before,” Carey says over Skype, her ink-black hair tucked back, speaking slowly and deliberately as if considering every word with the precision of, well, a scientist. “It feels like we’re pioneers.”

Carey has probably felt that way a lot lately. Not only does she study volcanoes for a living — making her part of a laughably tiny fraternity to begin with — she’s a submarine volcanologist, one of a handful in the world who study those underwater behemoths thousands of leagues beneath the sea. Add to that, she’s a woman, only 35 years old and located in the remote outpost of Tasmania, and you’ve got a very fringy member of the scientific community. Yet Carey’s theories on volcanic bubbles and underwater eruptions are already considered basalt-breaking.

While still a graduate student, Carey created a historic model for the buildup and eruption of the Icelandic volcano Askja. Scientists already knew that lava “bubbles” form and contribute to the gaseous mix that gives volcanoes the power to go kablooey. But Carey’s later research showed that those same bubbles are reabsorbed as pressure decreases, says geophysicist Michael Poland of the Cascades Volcano Observatory in Washington: “She was able to quantify it in a way that previously wasn’t possible.” In all, Carey’s contributions have helped form a timeline for eruptions that is useful to emergency personnel and first responders. You know, the kind of information Vesuvians would have liked to have had. Bruce Houghton, Carey’s Ph.D. supervisor at the University of Hawaii at Manoa, calls her “one of the top emerging volcanologists in the world.”

Carey’s more recent endeavors rival Lewis and Clark’s expeditions. A floating raft of pumice the size of Israel was spotted in the Pacific Ocean in 2012, and as the crumbling volcanic rock washed up in Australia and New Zealand, people wondered where it came from. Cue Carey, who tracked the explosion down to a little-known underwater volcano called Havre. In March, she helmed a three-week research mission to Havre and discovered that the eruption was the largest recorded underwater explosion in history. She led about 50 postdocs, grad students and crew members on the sea voyage, as well as two undersea robots: Sentry, a drone whose sonar took deep-sea photos, and Jason, which collected rock samples, sediments and marine life.

And with as little as we know about the seafloor, underwater volcanoes are shrouded in as much speculative science and mystery as Mount Wannahockaloogie in Finding Nemo. Old scientific models suggested volcanoes couldn’t erupt 1,000 meters or more below sea level — a sketchy analysis that Carey’s research has already disproved, since Havre’s hiccup likely occurred in vents as deep as 1,600 meters. Theorywise, scientists say that her work could inform evolutionary theory by explaining how pumice rafts may have carried species like barnacles and bristle worms from continent to continent. Practically speaking, Havre could shed light on the murky process of how volcanoes create precious metal deposits under the sea, from lead and zinc to copper and gold. Eventually, that understanding might inform potential commercial mining efforts.

Minerals were the reason Carey got into the brimstone business in the first place. Her parents weren’t hippies, she says, but “adventurous gypsies” who worked odd craft jobs as they bounced around from urban Sydney to rural Queensland to isolated Tasmania. When Carey was 8 years old, her parents owned a livestock farm in Kingaroy, a small outback town of fewer than 10,000 people. The backyard was a stone quarry full of colored quartz and fool’s gold. “I thought these gems were worth millions of dollars,” she says, laughing. Always a bit bookish, Carey was a pioneer of another sort: the first in her family to graduate from college. But while there was plenty of money in mining, she had no interest in pickaxes. Hence, Hawaii.

Submarine volcanology, however, isn’t exactly a field swimming in research funding, which could dampen Carey’s prospects. It can be a “challenging environment” to study, says Poland, the geophysicist, noting that there’s not much historical data about undersea eruptors compared with their land-bound cousins. And producing more data can be especially expensive. Underwater exploration takes a fleet of ships, submarine equipment and pressure-proof drones, cameras and sensors. Researchers often have just one chance to get it right. “We can never go back,” Carey admits.

Carey doesn’t seem worried, though. The Australian Research Council has funded her research for the foreseeable future, and she’ll add teaching to her job description in three years. She’s plenty busy; when asked about her hobbies, she pauses, says, “Ummm …,” and begins to laugh. Point taken. She’s doing important work. And if that means she has to miss a few Netflix nights to push humanity over the next great frontier, so be it.