NASA: Pluto's moon once had an underground ocean

Monday, June 16, 2014, 3:57 PM - A new study by NASA suggests that the interior of Pluto's moon Charon may have, at one point, been warm enough to sustain an underground ocean of liquid water.

Pluto's surface temperature is about -229C, making it far too cold for liquid water to form.

Its moon, Charon, isn't much better with an average surface temperature of -184C -- but fracture patterns on its surface led astronomers to believe something may have happened underground.

NASA says that an oval-shaped orbit could have, at one point, generated large tides and friction that may have produced enough heat to support an ocean of liquid water.

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"Our model predicts different fracture patterns on the surface of Charon depending on the thickness of its surface ice, the structure of the moon's interior and how easily it deforms, and how its orbit evolved," said Alyssa Rhoden of NASA's Goddard Space Flight Center, in a statement.

"By comparing the actual ... observations of Charon to the various predictions, we can see what fits best and discover if Charon could have had a subsurface ocean in its past, driven by high eccentricity."

NASA will be studying the theory in greater detail next year when the New Horizons spacecraft arrives in the Pluto system.

Caption courtesy of NASA: This is a mosaic of images showing cracks in Saturn's moon Enceladus taken by the Cassini spacecraft during its close flyby on March 9 and July 14, 2005. Image Credit: NASA/JPL/Space Science Institute

If the theory proves to be correct, Charon would be in good company.

Two other frigid moons in the solar system -- Saturn's Enceladus and Jupiter's Europa -- have subterranean oceans as well.

Telescope observations reveal that Charon's orbit has now stabilized and slowed down, so it likely isn't generating significant tides anymore. Because of this, any ocean that may be present would have frozen up a long time ago.

"Since liquid water is a necessary ingredient for known forms of life, the oceans of Europa and Enceladus are considered to be places where extraterrestrial life might be found," NASA says.

"However, life also requires a useable energy source and an ample supply of many key elements, such as carbon, nitrogen, and phosphorus. It is unknown if those oceans harbor these additional ingredients, or if they have existed long enough for life to form. The same questions would apply to any ancient ocean that may have existed beneath the icy crust of Charon."

More information on the study can be found on the NASA website.