The naming of moons has been the responsibility of the International Astronomical Union's committee for Planetary System Nomenclature since 1973. That committee is known today as the Working Group for Planetary System Nomenclature (WGPSN). Prior to its formation, the names of satellites have had varying histories. The choice of names is often determined by a satellite's discoverer; however, historically some satellites were not given names for many years after their discovery; for instance, Titan was discovered by Huygens in 1655, but was not named until 1847, almost two centuries later. Before the IAU assumed responsibility for astronomical nomenclature, only twenty-five satellites had been given names that were in wide use and are still used: 1 of Earth, 2 of Mars, 5 of Jupiter, 10 of Saturn, 5 of Uranus, and 2 of Neptune. Since then, names have been given to 137 additional planetary and dwarf planetary satellites: 52 satellites of Jupiter, 53 of Saturn, 22 of Uranus, 12 of Neptune, 5 of Pluto, 2 of Haumea, and 1 each of , , , and . Names have also been given to some satellites of minor planets, including the dwarf planet candidates and which have one satellite each. The number will continue to rise as current satellite discoveries are documented and new satellites are discovered. At the IAU General Assembly in July 2004, the WGPSN suggested it may become advisable to not name small satellites, as CCD technology makes it possible to discover satellites as small as 1 km in diameter. Until 2014, names were applied to all planetary moons discovered, regardless of size. From 2015, some small moons have not received names. Naming of moons by Solar System object Earth Every human language has its own word for the Earth's Moon, and these words are the ones normally used in astronomical contexts. However, a number of fanciful or mythological names for the Moon have been used in the context of astronomy (an even larger number of lunar epithets have been used in non-astronomical contexts). In the 17th century, the Moon was sometimes referred to as Proserpina. More recently, especially in science-fictional contexts, the Moon has been called by the Latin name Luna, presumably on the analogy of the Latin names of the planets, or by association with the adjectival form lunar. In technical terminology, the word-stems seleno- (from Greek selēnē "moon") and cynthi- (from Cynthia, an epithet of the goddess