is there such a thing as a blue moon
Blue moon The term has traditionally referred to an "extra" moon, where a year which normally has 12 moons has 13 instead. The "blue moon" reference is applied to the third moon in a season with four moons,[2] thus correcting the timing of the last month of a season that would have otherwise been expected too early. This happens every two to three years (seven times in the Metonic cycle of 19 years).[3] The March 1946 issue of Sky & Telescope misinterpreted the traditional definition, which led to the modern colloquial misunderstanding that a blue moon is a second full moon in a single solar calendar month with no seasonal link.
Moon The usual English proper name for Earth's natural satellite is "the Moon", which in nonscientific texts is usually not capitalized.[12][13][14][15][16] The noun moon is derived from Old English mōna, which (like all Germanic language cognates) stems from Proto-Germanic *mēnô, which comes from Proto-Indo-European *mḗh₁n̥s "moon", "month", which comes from the Proto-Indo-European root *meh₁- "to measure", the month being the ancient unit of time measured by the Moon.[17][18] Occasionally, the name "Luna" is used. In literature, especially science fiction, "Luna" is used to distinguish it from other moons, while in poetry, the name has been used to denote personification of our moon.[19]