Liquid Ocean World’s in the Solar System

Moons and asteroids with a global ocean are tending to become relatively common objects in the Solar System. There have been at least nine and now ten with Saturn’s tiny (250 mile across Mimas). Give of the moon’s of Uranus are also likely having deep buried oceans.

The presence of these long-lived global oceans is generally betrayed by surface modification owing to internal dynamics. Hence, Mimas would be the most unlikely place to look for the presence of a global ocean. Detailed analysis of Mimas’s orbital motion based on Cassini data, with a particular focus on Mimas’s periapsis drift, show that its heavily cratered icy shell hides a global ocean, at a depth of 20–30 kilometres. Eccentricity damping implies that the ocean is likely to be less than 25 million years old and still evolving. Simulations show that the ocean–ice interface reached a depth of less than 30 kilometers only recently (less than 2–3 million years ago), a time span too short for signs of activity at Mimas’s surface to have appeared.

The largest ocean in the solar system is on Ganymede, Jupiter’s largest and most massive moon. Confirmed in 2001, its estimated water volume is eight times greater than Earth’s world ocean. Most impressive are the calculated ice thickness of 62 miles and ocean depth of 93 miles.

Europa’s icy surface is about 10 miles thick and covers an ocean 60 miles deep. It’s estimated to have twice the water volume found on Earth.

The best estimate is that the volume of liquid water in our solar system is 25 to 50 times greater than that of water on Earth.

Ten Most Likely Liquid Ocean Planet, Moon or Asteroid

Terrestrial Planet: Earth
Our home planet, Earth, is the only body known to have life. Earth’s surface-land-to-water ratio is 29% land to 71% water.

Ocean World Status: Active – Dynamic ocean, known to support life

Moon of Jupiter: Europa
Scientists strongly suspect that a subsurface salty ocean lies beneath Europa’s icy crust. Tidal heating from its parent planet, Jupiter, maintains this ocean’s liquid state and could also create partially melted pockets, or lakes, throughout the moon’s outer shell.

Ocean World Status: Active? – Possibly a dynamic ocean, could support life

Moon of Saturn: Enceladus
Scientists predict that a regional reservoir about 6 miles (10 km) deep lies under a shell of ice 20 to 25 miles (30 to 40 km) thick at Enceladus’ south pole. This underground ocean is thought to feed the moon’s impressive jets, which spray from deep fissures (called “tiger stripes”) in the moon’s surface.

Ocean World Status: Active – Dynamic ocean, could support life

Dwarf Planet: Ceres
Scientists estimate that Ceres consists of about 25% water, a fraction of which could be in a liquid state. There are also clues that Ceres may have salty liquid below the surface and that it could have preserved an ocean deep underground. Data from NASA’s Dawn mission is continuing to provide new insights.

Ocean World Status: Possible – Evidence of an ocean, biological potential unknown

Moon of Jupiter: Ganymede
Ganymede is the largest moon in our solar system, and the only moon with its own magnetic field. Recent studies indicate a large, underground saltwater ocean is present at the Jovian moon. Ganymede could in fact have several layers of ice and water sandwiched between its crust and core.

Ocean World Status: Locked – Trapped ocean, unlikely to support life

Moon of Jupiter: Callisto
Callisto’s cratered surface lies at the top of an ice layer, which is estimated to be about 60 miles (100 km) thick. An ocean, which is thought to be at least 6 miles (10 km) deep, could be directly beneath the ice.

Ocean World Status: Locked – Trapped ocean, unlikely to support life

Moon of Saturn: Titan
Titan is believed to have a salty subsurface ocean – as salty as the Dead Sea on Earth – beginning about 30 miles (50 km) below its ice shell. It is also possible that Titan’s ocean is thin and sandwiched between layers of ice, or is thick and extends all the way down to the moon’s rocky interior.

Ocean World Status: Locked? – May have a trapped ocean, unlikely to support life if ocean is trapped

Moon of Saturn: Mimas
Research suggests that Mimas has either a subsurface ocean or that its core is shaped like a football. If Mimas is hiding a liquid water ocean, it lies 15 to 20 miles (25 to 30 km) beneath the moon’s impact-battered surface.

Ocean World Status: Possible – Evidence of an ocean, biological potential unknown

Moon of Neptune: Triton
Active geysers on Triton spew nitrogen gas, making this moon one of the known active worlds in the outer solar system. Volcanic features and fractures mark its cold, icy surface, likely results of past tidal heating. A subsurface ocean at Triton is considered possible, but is unconfirmed.

Ocean World Status: Possible – Evidence of an ocean, biological potential unknown

Dwarf Planet: Pluto
A world of many unknowns, Pluto could have rings and perhaps a subsurface ocean. Data from NASA’s New Horizons mission will provide new insights about this unexplored world.

Mars, our moon and many other places have lots of water in ice form. Below we discuss that five of the moons of Uranus are now believed to have liquid oceans.

Biggest Solid Objects in the Solar System With Densities

Densities and mean radii of the Uranian moons compared to those of other large moons and dwarf planets. Miranda has a low density similar to Saturn’s moon Mimas, whereas the densities of the other Uranian moons are more similar to Saturn’s moons Dione and Rhea

Five Uranus Moons Also Possible
Most of the major Uranian moons may host a residual ocean a few tens of kilometers thick at present, except for Miranda

Thermal metamorphism could create a late, second generation ocean in Titania and Oberon

These models represent a baseline for the formulation of observations with the Uranus Orbiter and Probe

The major moons of Uranus, Miranda, Ariel, Umbriel, Titania, and Oberon, are interesting targets for a future space mission because they might host liquid at present. Studying these bodies would help address the extent of habitable environments in the outer solar system. We model their thermal, physical, and chemical evolution. Because their heat budget is limited, with little or no tidal heating at present, we find that most of the moons can preserve only a few tens of kilometers of liquid until present. Furthermore, if the oceans are maintained by antifreeze, such as ammonia and chlorides, then their electrical conductivities may be close to zero. In this case, the detection of a magnetic field induced in these oceans would be challenging. We explore additional geophysical, as well as compositional, observations that would reveal the existence of a deep ocean in these moons. None of the scenarios studied produce residual liquid in Miranda at present. Our simulations are consistent with constraints on the dissipative properties of the moons inferred from dynamical evolution models.