Charon is the largest moon of Pluto, notable for its significant size relative to its parent body, its diverse geological surface features, and its mutual tidal locking with Pluto.

1. 1. Physical Characteristics

• • • Diameter: Charon has a diameter of about 1,212 km (753 miles), making it roughly half the size of Pluto.
    • Mass: Its mass is approximately 1.52 x 10^21 kg.
    • Density: Charon has an average density of about 1.71 g/cm³, indicating a composition of water ice and rock.

 

1. 2. Surface Features

• • • Surface Composition: Charon’s surface is primarily composed of water ice, with some regions covered in dark, reddish material likely made of complex hydrocarbons called Tholins.
    • Canyons and Rift Valleys: The moon has large canyons and rift valleys, such as the Serenitatis Chasma. These features suggest that Charon’s surface has been stretched and pulled apart.
    • Polar Cap: Charon has a polar cap at its north pole, which is thought to be composed of water ice.
    • Bright Spots: Some regions on Charon’s surface are much brighter than others, which may be due to the deposition of frozen gases from Pluto.

 

1. 3. Orbit

• • • Orbit around Pluto: Charon orbits Pluto at an average distance of about 19,570 km (12,186 miles). It takes approximately 6.39 Earth days to complete one orbit, which is the same amount of time it takes Pluto to rotate once on its axis.
    • Mutual Tidal Locking: Charon and Pluto are mutually tidally locked, meaning the same sides of both bodies always face each other.

 

1. 4. Temperature

Surface temperatures on Charon are extremely cold, averaging around -220°C (-364°F). This cold environment allows water ice to remain solid on its surface.

 

1. 5. Exploration

Charon was closely observed by NASA’s New Horizons spacecraft during its flyby of Pluto in July 2015. The spacecraft provided detailed images and data of Charon’s surface, revealing its geological features and surface composition.

 

1. 6. Scientific Significance

• • • Geological Activity: Charon’s surface features, such as canyons and rift valleys, suggest past geological activity, which provides insight into the moon’s thermal history and internal processes.
    • Surface Composition: The study of Charon’s surface and composition helps scientists understand the interactions between Pluto and its moon, as well as the formation and evolution of icy moons in the outer Solar System.

 

1. 7. Interesting Facts

• • • Largest Moon of Pluto: Charon is unique among the moons of dwarf planets because it is so large relative to Pluto. This large size-to-parent-body ratio makes Charon more comparable to a double planet system than a typical moon.
    • Surface Features: Charon’s surface shows a surprising diversity of features, including smooth plains, canyons, and possible cryovolcanic activity, suggesting a complex geological history.