NEW ORLEANS — How is a little Pacific island like the planet Mars?
Let James Garvin count the ways.
In December 2014, an underwater volcano amid the islands of Tonga in the South Pacific erupted. When the eruption ended and ashes settled a month later, a new island had emerged, rising 400 feet above the ocean’s surface.
Scientists unofficially named the island Hunga Tonga-Hunga Ha’apai, a concatenation of two older, uninhabited islands it nestles between.
Since then, scientists have been tracking how the new land mass has eroded and shifted. What they have found could make the island a Rosetta Stone to understanding volcanic features on Mars that also appear to have erupted underwater, providing clues about when the red planet was wet several billion years ago.
“We see things that remind us of this kind of volcano at similar scales on Mars,” said Dr. Garvin, the chief scientist at NASA’s Goddard Space Flight Center in Greenbelt, Md. “And literally, there are thousands of them, in multiple regions.”
He and colleagues presented the findings on Monday at a news conference at a meeting of the American Geophysical Union here.
Networks of river channels chiseled into Mars persuasively argue that liquid water once flowed across the red planet, but the current thinking of many planetary scientists is that Mars remained frozen through much of its history, punctuated with episodes of melting and flowing water.