Towering ice volcanoes have been identified on the surprisingly vibrant planet Pluto

WASHINGTON (Reuters) – A group of dome-shaped ice volcanoes unlike anything else known in our solar system and possibly still active on Pluto has been identified using data from NASA’s New Horizons spacecraft, showing that this distant, icy world. It is more dynamic than previously known.

Scientists said Tuesday that these ice volcanoes — which may number 10 or more — stand anywhere from six-tenths of a mile (1 kilometer) to 4-1/2 miles (7 kilometres). Unlike terrestrial volcanoes that spew gases and molten rock, the ice volcanoes of this dwarf planet spew large amounts of ice — apparently frozen water instead of some other frozen material — that might have the consistency of toothpaste, they said.

Features of the dwarf planet asteroid belt Ceres, Saturn’s moons Enceladus and Titan, Jupiter’s moon Europa and Neptune’s moon Triton have also been linked as freezing volcanoes. These are all different from Pluto, the researchers said, due to different surface conditions such as temperature and atmospheric pressure, as well as a different mixture of icy materials.

“Finding these features indicates that Pluto is more geologically active, or alive, than we previously thought,” said planetary scientist Kelsi Singer of the Southwest Research Institute in Boulder, Colorado, lead author of the study published in the journal. Nature Communications.

“The combination of these geologically recent features, which cover a vast area and are likely made of water ice, is surprising because it requires more internal heat than we thought Pluto would at this point in its history,” Singer added.

Pluto, smaller than Earth’s moon and about 1,400 miles (2380 km) in diameter, orbits about 3.6 billion miles (5.8 billion km) from the sun, nearly 40 times Earth’s orbit. Its surface is characterized by plains, mountains, craters and valleys.

Images and data analyzed in the new study, obtained by New Horizons in 2015, validate previous hypotheses about volcanic eruptions on Pluto.

Southwest Research Institute planetary scientist Alan Stern, principal investigator and study co-author, said the study not only found comprehensive evidence for the use of ice volcanoes, but also found that it lasted a long time, not a single episode.

“The most amazing thing about Pluto is that it is very complex — as complex as Earth or Mars despite its small size and its great distance from the Sun,” Stern said. “This was a real surprise from the New Horizons expedition, and the new finding on volcanic eruptions has reaffirmed this in a dramatic way.”

The researchers analyzed the area southwest of Sputnik Planitia, Pluto’s large, heart-shaped basin filled with nitrogen ice. They found large domes 18-60 miles (30-100 km) wide, sometimes combining to form more complex structures.

An elevation called Wright Mons, one of the tallest, may have formed from the merging of several volcanic domes, yielding a shape different from any terrestrial volcanoes. Although its shape is different, it is similar in size to the great Hawaiian volcano Mauna Loa.

Like Earth and the other planets in our solar system, Pluto formed about 4.5 billion years ago. Based on the lack of impact craters that typically accumulate over time, ice volcanoes appear to be relatively recent – formed in the past hundreds of millions of years.

“This is very young on a geological time scale,” Singer said. “Since there are virtually no impact craters, it is likely that these processes are continuing even nowadays.”

Pluto has plenty of active geology, including flowing nitrogen glaciers and the cycle in which glacial nitrogen evaporates during the day and condenses back into ice at night—a process that constantly changes the planet’s surface.

“Pluto is a geological wonderland,” Singer said. “Many regions of Pluto are very different from each other. If you just had a few pieces of the Pluto puzzle, you would have no idea what the other regions looked like.”

Reporting by Will Dunham; Editing by Rosalba O’Brien

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