Rhea

Rhea is a fascinating moon in our Solar System that has captured the attention of astronomers and space enthusiasts alike. With a Rhea radius of 1,528.6 km, making it 4.2× smaller than Earth's size, this celestial body presents unique characteristics that distinguish it from other objects in our cosmic neighborhood. Positioned at an average distance of 527,068 km (0.004 AU) from the Sun, Rhea occupies a significant place in the Solar System's architecture. As a moon, Rhea demonstrates the incredible diversity of natural satellites that orbit larger celestial bodies throughout our Solar System.

The Rhea physical characteristics reveal a world of remarkable dimensions and properties. The Rhea radius measures 1,528.6 km, making it 4.2× smaller than Earth's size. The Rhea mass of 2.30e+21 kg represents 2596.5× smaller than Earth's mass, giving this world substantial gravitational influence.

The Rhea orbit reveals fascinating details about its journey around the Sun and its relationship to other Solar System objects. The Rhea orbit has a semimajor axis of 527,068 km (0.004 AU), placing it 283.8× smaller than Earth's distance from the Sun. At its closest approach (perihelion), Rhea comes within 526,543 km of the Sun, while at its farthest point (aphelion), it reaches 527,597 km, creating a 0.2% variation in solar distance. The Rhea orbit is nearly circular with an eccentricity of 0.001 (16.7× smaller than Earth's orbital eccentricity), resulting in relatively stable solar heating throughout its year. The Rhea orbit takes 0.00 hours to complete (6984982.2× smaller than Earth's orbital period), defining the length of its year. The orbital inclination of 0.35° indicates how much the Rhea orbit is tilted relative to the Solar System's ecliptic plane. This low inclination means Rhea follows a path very close to the plane where most planets orbit, suggesting a stable formation history.

The Rhea rotation and axial orientation provide crucial insights into its daily and seasonal cycles, as well as its orbital dynamics. The Rhea rotation period of 0.03 hours (794.6× smaller than Earth's rotation period) determines the length of its day. This extremely fast rotation creates intense centrifugal forces and may contribute to the planet's flattened shape. The Rhea axial tilt of 0° determines the intensity and nature of seasonal variations. With minimal axial tilt, Rhea experiences virtually no seasonal changes, maintaining relatively constant temperatures throughout its year. The orbital orientation parameters reveal additional details about Rhea's position in space. The mean anomaly of 0° indicates the planet's current position in its orbit relative to its perihelion. The argument of periapsis of 0° shows how the orbit's orientation changes over time due to gravitational perturbations. The longitude of ascending node of 0° defines the reference point where the orbit crosses the ecliptic plane.

The Rhea temperature and atmospheric conditions are fundamental to understanding its habitability and environmental characteristics. The Rhea average temperature of 0.0 K (-273.1 °C) (-459.7°F) provides the baseline for understanding its climate. These extremely cold temperatures make Rhea inhospitable to life as we know it, with any atmosphere likely frozen solid on the surface. Compared to Earth's average temperature of 15°C (59°F), Rhea presents a dramatically different thermal environment. Being closer to the Sun than Earth, Rhea receives more intense solar radiation, contributing to its temperature profile.

The Rhea escape velocity and shape characteristics reveal important details about its gravitational field and rotational dynamics. The Rhea escape velocity of 0 m/s determines how easily objects can break free from its gravitational pull. This relatively low escape velocity means that gases and light molecules can easily escape into space, making it difficult for Rhea to retain a substantial atmosphere. The Rhea flattening of 0.0000% indicates how much the planet's rotation affects its shape. This minimal flattening suggests a nearly spherical shape, indicating either slow rotation or a very rigid internal structure.