At the far end of the Solar System, far from the Sun’s heat and light, a truly unique world floats in the alien darkness.
Pluto, new research has found, has a landscape depicted by ice volcanoes, of a type and scale not seen anywhere else in the Solar System. In the southwest of the Sputnik Planitia so much sludge has erupted from below the surface of Pluto that mountains of ice stand up to 7 kilometers (4.3 miles) high.
“One of the regions with very few impact craters is dominated by enormous rises with hummocky flanks. Similar features do not exist anywhere else in the illustrated Solar System,” writes a team of researchers led by planetary scientist Kelsi Singer of the Southwest Research Institute.
“The existence of these massive features suggests that Pluto’s internal structure and evolution allow for either improved heat retention or more heat in general than was expected before New Horizons.”
As the name suggests, rather than hot molten lava, ice volcanoes erupt with hazy water letters of volatile compounds such as ammonia and methane. As soon as they appear above ground in icy atmospheric conditions, they freeze and build up surface monuments, much like lava can create volcanic mountains and calderas, just… well, colder.
The first hint of ice volcanoes, known as cryovolcanism, was detected on Pluto in 2015, when the New Horizons probe made its epic flight from our Solar System’s former ninth planet.
Never before have scientists had access to such a wealth of data on the Kuiper Belt’s largest known inhabitant; and not far from the heart-shaped countryside of the Sputnik Planitia, some features stood out as truly interesting.
Of these, Wright Mons and Piccard Mons have been tentatively identified as ice volcanoes, large hills with apparently deep holes in their centers, very similar to volcanic features elsewhere in the Solar System.
Later analysis by Singer and colleagues revealed that the heights of the topography may seem more pronounced than they are, due to the oblique lighting at the terminator (the line separating day and night), which slightly confuses the issue. .
Now, Singer and her team have done an in-depth analysis and found that the site is likely still being imaged by cryovolcanism. The reason why it may look different from other such sites in the Solar System is that the processes and environment are different; “Unique to Pluto,” they wrote.
Moreover, it must have happened quite recently in the history of the dwarf planet. This is because there is only one crater on the side of Wright Mons, indicating that it did not have enough time to bump through multiple impacts and get scars.
Characteristics of ice volcanoes have been observed on several worlds throughout the Solar System, including the dwarf planet Ceres, Saturn’s moon Titan, Jupiter’s moon Europe and even Pluto’s moon Charon. But cryovolcanism can be difficult to positively identify because there are no current processes on earth of the same nature with which we can compare it.
In the cryovolcanic landscape on the edge of the Sputnik Planitia, many such hills have multiplied, Singer and team found. The creation of such a site would require multiple eruption sites and a large volume of erupting material – about 10,000 cubic kilometers, or the value of 4 billion Olympic-sized swimming pools. The volume of Wright Mons alone is comparable to the Mauna Loa caldera in Hawaii.
It is unclear exactly what processes in the depths of Pluto could have caused such a scale of cryovolcanism. It is possible that there is a deep network of fractures beneath the site, one that has since been covered by the flowing and hardening cryomagma.
The new discovery suggests that, although frozen, Pluto may be very far from dead and inert. In fact, the small, distant dwarf planet may have much to teach us about cryovolcanism.
“The range of cryovolcanic features found across the Solar System is diverse. With the different conditions and surface materials present at Pluto, it is quite possible that any material movement on the surface may not look like that of other bodies,” the team written.
“The squeezing of icy material on the surface of a body with extremely low temperatures, low atmospheric pressure, low gravity, and the abundance of volatile ice found on Pluto’s surface make it unique among the visited places in the Solar System. . “
The research was published in Nature communication.