On Pluto’s surface, strange bumps that have never been observed in the solar system indicate that there were active ice volcanoes until recently, says a study published in Nature Communications on Tuesday (29).
Analysis of images taken by NASA’s New Horizons spacecraft suggests that Pluto’s interior temperature remained higher than previously thought, long enough to allow for this phenomenon.
Instead of spewing lava, cryovolcanoes eject “a thick, muddy mixture of water and ice, or maybe a solid fluid like Earth’s glaciers,” Kelsi Singer, a planetary scientist at the Southeast Research Institute in Colorado, told AFP.
The existence of cryovolcanoes on different moons of the solar system, such as the largest satellite of Neptune, Triton, is known. But those on Pluto “appear to be very different from anything we’ve seen so far,” added the study’s co-author.
On this dwarf planet, “large areas of enormous ice volcanoes can be observed, with a remarkable texture of wavy relief”, he said.
It is difficult to precisely date the formation of these volcanoes, “but we believe they could be a few hundred thousand years old or even less,” according to Singer.
A small number in a story that is millions of years old.
Liquid water conservation?
Given that the region where these formations are located lacks impact craters, caused by asteroids, scientists do not rule out the possibility that ice volcanoes continue to form there.
These findings are “very important,” Lynnae Quick, a planet expert and cryovolcano specialist at NASA’s Goddard Space Flight Center, told AFP.
“They suggest that a small body like Pluto, which should have lost most of its internal heat long ago, managed to retain enough energy to fuel extensive geological activity quite late in its history,” he explained.
“This information should allow us to reassess the possibility of conserving liquid water on small icy worlds far from the sun” in the Kuiper belt where Pluto is located.
David Rothery, a professor of planetary geoscience at the UK’s Open University, explained that “it is not known what provided the heat necessary for the eruption of these ice volcanoes”.
One of these structures, Mount Wright, about 5 kilometers high and 150 kilometers in diameter, has a volume similar to one of the largest volcanoes on earth, Mauna Loa in Hawaii.
And this is despite Pluto being considerably smaller than Earth.
The New Horizons probe, which took the images, was the first spacecraft to explore Pluto in 2015.
“But we have a lot to learn about the solar system,” concludes Kelsi Singer.
