By SARI AMIEL Science & Technology Editor
As it continues its voyage across the solar system, NASA’s New Horizons mission is still revealing new, unexpected facts about the solar system. Newly released photos from the spacecraft show two large mountains that might be volcanoes on the surface of Pluto.
These mountains, which are hundreds of miles wide, have craters at their centers and resemble Earth’s shield volcanoes.
They are thought to be made from nitrogen ice. Given that the planet’s surface is covered in ice, these would be considered “cryovolcanoes,” which are volcanoes that emit melted ice rather than burning rocks.
At a news conference located at NASA’s Ames Research Center on Nov. 9, scientists explained that they did not previously think Pluto was large enough to contain enough internal heat to power volcanism.
It is still not clear whether the large mountains are indeed volcanoes, but scientists have begun to advance explanations as to what could power volcanism on Pluto. One theory suggests that Pluto has an ammonia-water slurry mantle, which could cause a rise in hot matter from underneath the planet’s surface. Another possibility is that Pluto’s core is still cooling from its formation, and heat from this process sometimes rises through volcanoes.
“Nothing like this has ever been seen in the solar system,” Oliver White, a postdoctoral researcher working with New Horizons, said at the press conference. “This is the first time where we see what seem to be tall volcanic edifices.”
Titus and Enceladus, both icy moons belonging to Saturn, have also been thought to have some volcanic activity, but this activity was not associated with large mountains.
Some scientists believe that Pluto could have a whole field of cryovolcanoes, but this would not be visible from New Horizon’s vantage point.
“We’ll have to go back in a hundred years and see,” White said at the conference.