NASA completes Webb Space Telescope rollout deployment to begin scientific missions this summer. Photo: VCG

Strange lumpy terrain on Pluto unlike anything previously observed in the solar system indicates that giant ice volcanoes were active relatively recently on the dwarf planet, scientists said on Tuesday.

The observation, which was made by analyzing images taken by NASA's New Horizons spacecraft, suggests that Pluto's interior was hotter much later than previously thought, according to a new study in the Nature Communications journal.

Rather than shooting lava into the air, ice volcanoes ooze a "thicker, slushy icy-water mix or even possibly a solid flow like glaciers," said Kelsi Singer, study author and planetary scientist at Colorado's Southwest Research Institute.

Ice volcanoes were already thought to be on several chilly moons in the solar system, but Pluto's "look so different from anything else we ever have seen," Singer told AFP.

Singer said it was difficult to pinpoint exactly when the ice volcanoes were formed "but we believe they could be as young as a few hundred million years or even younger."

Unlike much of Pluto, the region does not have impact craters, which means "you cannot rule out that it is still in the process of forming even today," she added.

Lynnae Quick, a planetary scientist at NASA's Goddard Space Flight Center specialized in ice volcanoes, said the findings were "extremely significant."

"They suggest that a small body like Pluto, which should have lost much of its internal heat long ago, was able to hold onto enough energy to facilitate widespread geological activity rather late in its history," she told AFP.

AFP