Newest island in Pacific may offer clues about Mars
Four years ago, an underwater volcano erupted in the South Pacific Ocean, creating a new island. And NASA took notice.
The island’s evolution could hold clues to how water might have shaped similar features on Mars billions of years ago, NASA officials believed, so the space agency began collecting satellite photos to track how the elements were carving and clawing away at the land.
The images yielded insights into how the island was eroding, but the story they told was limited. NASA could wring more information from those photographs with measurements taken from the ground, but James Garvin, chief scientist at NASA’s Goddard Space Flight Center in Greenbelt, Maryland, could not justify the cost of sending a team. Then an opportunity presented itself.
The Sea Education Association, a study abroad program, was planning to take a group of college students and faculty and staff members to the island, and NASA was welcome to hitch a ride.
Garvin jumped at the chance, sending along Dan Slayback, a research scientist for NASA who had been working on the effort to track the island’s progression.
Slayback sailed on that trip in fall, finding an island of black rock that was, to his surprise, also teeming with life.
“It was very dramatic,” he said. “Just beautifully dramatic.”
The island, part of Tonga, is about 500 acres in size and about 1,300 miles northeast of New Zealand. It has not yet been named, but is unofficially referred to as Hunga Tonga-Hunga Ha’apai, a combination of the names of the two older, uninhabited islands it sits between. (A land bridge connects all three.)
Its most prominent features are a turquoise lake and a croissant-shaped ridge — the remnants of a cone made from hardened ash — that stretches about 400 feet high and about a mile across, Slayback said.
After spending years staring at satellite photographs of the island, he was overwhelmed to finally see the breathtaking landscape up close in early October. He was also eager to get to work.
The satellite photos reveal how the island has eroded over time, but their level of detail is limited without 3D points of reference as context. So, with the help of the students, Slayback roamed the island with a finely tuned GPS device, recording the location of various features visible in the photographs with an accuracy of a few inches.
Those measurements will allow the NASA team to refine the models it had created and more narrowly track erosion going forward, Garvin said.
“Instead of a map with a resolution the size of a chair that you’d sit at your desk in, we have a map of the topography, the three-dimensionality, of this new island that’s good to the size of a few fingers,” he said.
With those finer models, scientists can better compare the changing shape of Hunga Tonga-Hunga Ha’apai to volcanic shapes and erosion patterns on Mars to better understand the degree to which water was present there and the role it might have played in shaping the landscape.
In addition to helping Slayback with the measurements, students and faculty collected rock samples and documented the vegetation growing on the island. They were also surprised to find a thriving bird population.