Charon (moon)

Charon Discovery

Pluto-Charon system-new

Charon, Earth & Moon size comparison

CharonFeatureMap Annotated

Pluto & Charon - Mountains Craters and Plains

PIA20375-PlutoMoon-Charon-NightSide-20150717

Charon is the largest moon of Pluto, discovered in 1978 by astronomer James Christy. It is named after the ferryman of the dead in Greek mythology, reflecting its association with the underworld figure Pluto. Charon and Pluto are often referred to as a binary system because the barycenter of their orbits does not reside within either body. Instead, it lies in the space between them, making their orbit around each other unique among the planets and their moons in the Solar System.

Discovery and Naming

The discovery of Charon was a significant event in the study of the outer Solar System. Before its discovery, little was known about Pluto, and the finding of a moon provided astronomers with new avenues to explore Pluto's mass and composition. The name "Charon" was officially adopted by the International Astronomical Union (IAU) in 1985, following the tradition of naming celestial bodies after mythological figures.

Physical Characteristics

Charon is about half the size of Pluto, making it one of the largest moons in the Solar System relative to its parent planet. It has a diameter of approximately 1,212 kilometers. Charon's surface is composed primarily of water ice, with regions of frozen ammonia and other volatiles. The moon exhibits a diverse range of terrains, including canyons, craters, and plains.

One of the most striking features of Charon is a large canyon system that rivals the Grand Canyon in depth and exceeds it in length. This feature suggests a complex geological history that may include past tectonic activity.

Orbit and Rotation

Charon orbits Pluto at a distance of about 19,600 kilometers, with an orbital period of about 6.4 Earth days. Both Charon and Pluto are tidally locked, meaning they always show the same face to each other. This synchronous orbit is a result of gravitational forces that have synchronized their rotation periods.

Exploration

The most detailed exploration of Charon came from the New Horizons mission, which flew by the Pluto-Charon system in July 2015. The spacecraft provided high-resolution images and data on Charon's surface composition and topography, revealing a young surface that suggests geological activity in the moon's recent past.

Significance

The study of Charon, alongside Pluto, provides valuable insights into the processes that shape the icy bodies in the Kuiper Belt and beyond. Understanding Charon's geology and composition helps astronomers piece together the history of the outer Solar System and the formation of similar binary systems.

See Also

• Pluto
• New Horizons
• Kuiper Belt
• Solar System