According to analysis of the fractures of cracks in the icy surface of Pluto’s giant moon Charon could reveal that its interior was warm, perhaps warm enough to have maintained a subterranean ocean of liquid water, reports a new NASA-funded study.
Orbiting the sun more than 29 times farther than Earth, Pluto is an extremely distant world. The environment at Pluto is far too cold to allow liquid water on its surface with a surface temperature estimated to be about 380 degrees below zero Fahrenheit (around minus 229 degrees Celsius). Pluto’s moons are in the same frigid environment.
In July of 2015 NASA’s New Horizons spacecraft will be the first to visit Pluto and Charon as Pluto’s remoteness and small size make it difficult to observe and will provide the most detailed observations till date.
According to Alyssa Rhoden of NASA’s Goddard Space Flight Center in Greenbelt, Maryland, “The 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”.
He further added “By comparing the actual New Horizons 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.”
Jupiter’s moon Europa and Saturn’s moon Enceladus are other examples in the outer solar system to have cracked surfaces with evidence for ocean interiors.
A gravitational tug-of-war between their respective parent planets and neighboring moons keeps their orbits from becoming circular while Europa and Enceladus move in their orbits.
Daily tides that flex the interior and stress the surface is raised by these moons as they have eccentric (slightly oval-shaped) orbits. Subsurface oceans interiors on Europa and Enceladus are kept warm by tidal heating, according to a study.
Further the study finds that high eccentricity could have generated large tides, causing friction and surface fractures in Charon’s case.
According to a solar system record about one-eighth of Pluto’s mass, the moon is unusually massive compared to its planet. After a giant impact ejected material off the planet’s surface, it is thought to have formed much closer to Pluto. The material went into orbit around Pluto and coalesced under its own gravity to form Charon and several smaller moons.