NATIONAL HARBOR, Md., Nov. 9 (UPI) -- New imagery from the New Horizons mission reveals a pair of mysterious mountains on Pluto's south pole. Scientists with NASA think they could be ice volcanoes.
The mountains feature broad slopes, measuring only a few miles high but nearly 100,000 miles across. Each is topped by a significant crater. Researchers found the formations while compiling a three-dimensional topographical map of Pluto's surface.
The ice volcanoes suggestions is very much a working theory. The idea was floated by NASA scientists on Monday as they presented the latest New Horizons findings at the 47th annual meeting of the American Astronomical Society's Division for Planetary Sciences, being held in National Harbor, Md.
"We're not yet ready to announce we have found volcanic constructs at Pluto, but these sure look suspicious, and we're looking at them very closely," Jeff Moore, a planetary scientist at NASA's Ames Research Center in Moffett Field, Calif., and member of the mission's geology team, told Nature.
Still, the features are remarkably similar to volcano structures on Earth and Mars.
"These are big mountains with a large hole in their summit, and on Earth that generally means one thing -- a volcano," Oliver White, New Horizons postdoctoral researcher at NASA's Ames Research Center, said in a press release.
"If they are volcanic, then the summit depression would likely have formed via collapse as material is erupted from underneath," White added. "The strange hummocky texture of the mountain flanks may represent volcanic flows of some sort that have traveled down from the summit region and onto the plains beyond, but why they are hummocky, and what they are made of, we don't yet know."
After surveying the various concentrations of craters on Pluto's surface -- some regions smooth and unblemished, others especially peppered -- researchers have become quickly convinced that the dwarf planet is geologically active. Pluto boasts smooth icy plains and tall rugged mountains.
As to what generates the dwarf's volcanic energy, scientists aren't sure. Typically, the gravitational interplay between planet and moon is what stirs up geologic innards. But Pluto has no moon.
Scientists think the elements that first formed Pluto may be radioactive. As they decay beneath Pluto's surface, chemical reactions may heat up the dwarf planet's insides.
The New Horizons probe, which executed its Pluto flyby in July, is still sending back data, and researchers hope they may soon be able to say more about the potential volcanoes.
"If we can constrain the compositions of these features, then we'd have something to work with, with respect to modelling how this particular ice would behave if it were to be erupted volcanically, and what sort of relief it might be able to sustain," White told the BBC.