Key Facts about Charon

About Charon:

• It is the largest of Pluto's five moons, about half the size of Pluto.
• It was discovered telescopically on June 22, 1978, by James W. Christy and Robert S. Harrington at the U.S. Naval Observatory station in Flagstaff, Arizona. 
• The moon was named for Charon, the ferryman of dead souls to the realm of Hades (the Greek counterpart of the Roman god Pluto) in Greek mythology.
• Charon is 754 miles (1,214 kilometers) across, and Pluto is about 1,400 miles wide.
• Its mass is more than one-tenth of Pluto’s mass.
• Since, Charon is solarge and massive with respect to Pluto– the two are sometimes referred to as a double dwarf planet system.
• The distance between them is 12,200 miles (19,640 km).
• The same surfaces of Charon and Pluto always face each other, a phenomenon called mutual tidal locking.
• In addition, Charon always shows the same hemisphere to Pluto, because (like many other moons) its rotation period is identical to its orbital period.
• Charon orbits Pluto every 6.4 Earth days.

Q1: What is Tidal locking?

Tidal locking is the phenomenon by which a body has the same rotational period as its orbital period around a partner. So, the Moon is tidally locked to the Earth because it rotates in exactly the same time as it takes to orbit the Earth. That is why we only see one side of the Moon. If both bodies are of comparable size and are close together, both bodies can be tidally locked to each other – this is the case in the Pluto-Charon system.

Source: Carbon dioxide, hydrogen peroxide detected on Pluto's largest moon 'Charon'