Is­land may show how wa­ter shaped Mars

Dayton Daily News - - NATION & WORLD - Ni­raj Chok­shi

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 3-D 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.

“The num­ber of birds, the num­ber of bird eggs, the num­ber of baby chicks was as­tound­ing,” said Rachel Scud­der, chief sci­en­tist for the Sea Ed­u­ca­tion As­so­ci­a­tion. “There were places where we could not ac­tu­ally get up to the wall of the caldera for fear of step­ping on baby chicks.”

The birds in­cluded nest­ing sooty terns and at least one barn owl, Slay­back said. The group also found grass and beach morn­ing glo­ries sprout­ing from soil-like patches on the is­land’s other­wise bar­ren, rocky sur­face.

They came across signs of hu­man life, too: Garbage was strewed about parts of the is­land. Most likely was churned up in 2018 by Trop­i­cal Cy­clone Gita, though some of the trash might have been left be­hind by vis­i­tors from nearby is­lands, ac­cord­ing to Jef­frey Wescott, an an­thro­pol­ogy pro­fes­sor with the pro­gram. The stu­dents filled and re­moved about a dozen bags of trash, most of it plas­tic bot­tles.

The vol­canic erup­tion that birthed the is­land oc­curred in De­cem­ber 2014, send­ing ash as high as 30,000 feet into the air and dis­rupt­ing flights. The is­land was formed in part when that ash fell back to earth and hard­ened af­ter mix­ing with warm wa­ter, Garvin said.

When the is­land was cre­ated, the NASA team thought it might not sur­vive much longer than a decade. (That was part of the rea­son it could not jus­tify send­ing a team there.) Now, af­ter sam­pling rocks from the is­land, vis­it­ing it and watch­ing it weather the el­e­ments, the team ex­pects it to re­main for any­where from a few decades to hun­dreds of years.

“Right now, things look good,” Garvin said. “The is­land may be ce­ment­ing it­self.”

DAN SLAY­BACK / VIA THE NEW YORK TIMES

Beach morn­ing glo­ries grow on an is­land formed by vol­canic ac­tiv­ity four years ago in Tonga, in the South Pa­cific.

DAN SLAY­BACK / VIA THE NEW YORK TIMES

The beach of a new is­land formed by vol­canic ac­tiv­ity be­tween two ex­ist­ing is­lands that are part of Tonga is shown in the South Pa­cific. The new is­land’s evo­lu­tion could hold clues to how wa­ter might have shaped sim­i­lar fea­tures on Mars bil­lions of years ago.

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