A recently formed ocean inside Saturn's moon Mimas.

Area of Science:

• Planetary Science
• Astrobiology
• Solar System Exploration

Background:

• Global oceans are increasingly recognized on moons throughout the Solar System.
• Surface features often indicate the presence of subsurface oceans due to internal activity.
• Mimas, a small icy moon, was previously considered an unlikely candidate for a global ocean.

Purpose of the Study:

• To investigate the possibility of a global ocean within Saturn's moon Mimas.
• To analyze Mimas's orbital dynamics for evidence of internal ocean activity.

Main Methods:

• Detailed analysis of Mimas's orbital motion using Cassini spacecraft data.
• Focus on Mimas's periapsis drift to infer subsurface conditions.
• Orbital dynamics modeling to constrain ocean age and depth.

Main Results:

• Evidence indicates Mimas possesses a global ocean beneath its icy shell, at a depth of 20-30 kilometers.
• Eccentricity damping suggests the ocean is less than 25 million years old and actively evolving.
• Ocean-ice interface reached its current depth recently (within the last 2-3 million years).

Conclusions:

• Mimas harbors a young, evolving global ocean, contrary to prior expectations.
• The recent formation of the ocean explains the lack of observable surface activity.
• This finding expands the potential for habitable environments within the Solar System.