Images of Pluto's surface have revealed the dwarf planet's hidden secret: a network of giant ice volcanoes. According to astronomers behind the discovery published this week in Nature Communications the volcanoes appear to have erupted in an icy slush relatively recently.
The region is located southwest of the Sputnik Planitia ice sheet, which covers an ancient impact basin stretching 621 miles (1,000 kilometers) across. Largely made of bumpy water ice, it's filled with volcanic domes. Two of the largest are known as Wright Mons and Piccard Mons.
"There was no other areas on Pluto that look like this region," says study author Kelsi Singer, a planetary scientist at the Southwest Research Institute, told Space's Rebecca Sohn. "It's totally unique in the solar system."
The area around the volcanoes doesn't have the impact craters usually dotted across Pluto's surface, which suggests the colony of cryovolcanoes were active around 100 to 200 million years ago. Given the ice volcanoes’ relatively recent activity, it’s possible that they may erupt in the future.
The International Astronomical Union (IAU) downgraded the status of Pluto to that of a dwarf planet because it did not meet the three criteria the IAU uses to define a full-sized planet. Essentially Pluto meets all the criteria except one—it“has not cleared its neighboring region of other objects.”