Pluto might have an underground ocean, if those icy volcanoes are any indication.

Science magazine reports on new conclusions from the New Horizon spacecraft’s 2015 observations of ice volcanoes on Pluto, and what they could mean for the interior structure of the cold dwarf planet:

A 1000-kilometer stretch of terrain on Pluto is dominated by volcanic domes and structures that would have formed recently from flowing water-ice lava, the researchers write this week in Nature Communications. Such activity might arise from a liquid ocean lying deep under the formations, though that hypothesis is hard to prove.

There’s a photo at the link, and you can read the Nature article here.