Charon

Charon, the largest moon of Pluto, was discovered on June 22, 1978, by James Christy, who observed irregularities in images of Pluto. Initially designated as 1978 P1, it was named Charon in honor of the mythological ferryman of souls and the discoverer's wife, Charlene. In 1985, further observations confirmed the moon's existence during eclipses, solidifying the discovery's status. Charon orbits Pluto in a period equal to its rotation—6 days, 9 hours, and 17 minutes—meaning both bodies are tidally locked, always showing the same face to each other. With a diameter of 1,212 km, it is half the size of Pluto, and combined with their mass difference, the Pluto-Charon system is often referred to as a binary dwarf planet. As for Charon's chemical composition, it is believed to be covered in water ice under extreme conditions (-220°C). Thanks to the Hubble Telescope and the New Horizons mission in 2015, valuable information about the moon's structure has been obtained. In pop culture, Charon appears in the Mass Effect series as a mass relay and in Joe Haldeman's novel "The Forever War" as a training planet. The discovery and study of Charon have become a significant part of astronomical history, providing insight into the unique properties of the Pluto-Charon system and inspiring generations of scientists and creators.