A team of researchers at Brown University have uncovered evidence that there might be liquid water beneath the dwarf planet Pluto’s icy surface.
If the global liquid ocean had solidified, the heavy outer ice shell would have crushed the freezing ocean into a strange type of ice called ice-II. Unlike typical ice, which expands as it freezes, ice-II takes up less volume than liquid water.
As a result, the entire dwarf planet would have shrunk, causing the surface shell to buckle and scrunch up in distinctive ways, “like the skin of an overripe peach wrinkling as it dries,” writes Conor Gearin for New Scientist.
Instead, the New Horizon’s probe recorded deep cracks marking Pluto’s surface. That leads researchers to conclude that something, perhaps heat radiating from radioactive elements in the dwarf planet’s core, is keeping the ocean on Pluto wet.
“The fact that even cold, distant Pluto could have a subsurface ocean means that there are potential habitats even in apparently unpromising locations,” said Francis Nimmo, a New Horizons scientist based at the University of California, Santa Cruz.
However, this does not in any way mean Pluto would be a suitable home for Earth-dwelling organisms.
“Such distant oceans would be very different from what we’re accustomed to on Earth,” notes Nadine Barlow, an astronomer at Northern Arizona University. “Besides being locked beneath dozens of feet of ice, a Plutonian ocean would almost certainly have a different composition than Earth’s seas.”
We have to remember that the ices out at Pluto not only include water ice but also carbon dioxide and methane ices,” says Barlow. “Compared to our seas, Pluto’s potential ocean would also likely be especially briny, rich in dissolved salts and ammonia that would help reduce its freezing point and keep it in a liquid state.