Pluto may be warm enough to harbour ocean beneath its ice shell

WASHINGTON - New research has suggested that Pluto may be warm enough to contain an ocean beneath its miles-thick ice shell.

And that ocean wouldn’t be a mere puddle but 60 to 105 miles, thick beneath a 120-mile (200-kilometer) layer of ice, noted planetary scientist Guillaume Robuchon of the University of California, Santa Cruz.

Even though Pluto’s surface is probably colder than -230 degrees Celsius, there could still be plenty of liquid-preserving heat beneath the ice cap, the new model suggests, reports National Geographic News.

“Ice is a good insulator,” said Robuchon’s collaborator, Francis Nimmo, also of the University of California, Santa Cruz.

The model readily produces an under-ice ocean, as long as Pluto’s core rocks contains at least a hundred parts per billion of radioactive potassium.

However, for an ocean to exist, Pluto’s rocks must be concentrated in a rocky core, with water and ice layered on the surface.

When the New Horizons spacecraft reaches Pluto in 2015, it will test whether Pluto actually has a subsurface ocean. If there’s no ocean, Pluto should be comparatively flattened at its poles, containing a “fossil” equatorial bulge left over from early in its history, when the body was spinning more rapidly.

And if there indeed is an ocean on the planet, the surface should show cracks created as Pluto gradually lost heat and the ice cap thickened over billions of years. That’s because the freezing ice would have expanded, causing the surface to bulge upward, cracking in the process. If there was only ice, and never an ocean, the cooling of the planet should have contracted the ice rather than expanded it. Once formed, ice contracts as it cools.

“We’re making predictions,” Nimmo said, “and will find out whether they’re right or wrong when New Horizons gets there.” (ANI)