Moon

A moon (also known as a natural satellite) was an astronomical object found in orbit around a planet.
Some moons, like Voga, were planetoids brought into orbit around a planet by the planet's gravity, while others were the result of a collision between objects during the formation of a solar system. (TV: Revenge of the Cybermen)
==Mutter's Spiral==
===Sol===
By the year 200,000, Earth was orbited by five moons. (TV: The Long Game) Earth's first Moon was in fact an alien egg and hatched in 2049, being replaced immediately by another egg the hatchling laid. (TV: Kill the Moon) By the time of the Fourth Great and Bountiful Human Empire, the Earth had four additional moons. (TV: The Long Game, Bad Wolf) 
The Third Doctor sang of Martian moons, (TV: Inferno) of which there were two: Deimos and Phobos. (AUDIO: Deimos, Phobos)
On 7 January 1610, Galileo Galilei wrote in a letter that he had spotted three of Jupiter's moons. A few months later, he discovered a fourth. The final moon, the golden planet of Voga, would not be discovered by humans until the 29th century. (PROSE: Time Traveller's Diary)
===Kasterborous===
Across its history, Gallifrey had at least three moons. An unnamed satellite, the heavily industrialised Pazithi Gallifreya (COMIC: Agent Provocateur) and the lost moon, Botoya. Built into the latter was a device that could rewrite history on a grand scale, which was why the Doctor suspected the ancients of Gallifrey had hidden the moon. Botoya subsequently became a legend in Gallifreyan culture, one not widely believed in. (AUDIO: The End of the Beginning)
By some accounts of the Doctor and Susan's escape from Gallifrey, the First Doctor had stolen one of Gallifrey's moons, (TV: The Magician's Apprentice, PROSE: A Brief History of Time Lords) though the Twelfth Doctor defended to Clara Oswald that he'd only lost the moon. (TV: Hell Bent)
==Other moons==
The Eleventh Doctor once offered to take Amy Pond and Rory Williams to a moon that was actually made of honey for their honeymoon. He later corrected himself, saying it wasn't made of actual honey, and it wasn't actually a moon. It was in fact technically alive "and a bit carnivorous, but there are some lovely views." (TV: A Christmas Carol)
The Shadow Proclamation tended to the matter of "suicide moons". (TV: The Magician's Apprentice)
Kepzyr, a moon of Zorbos, was well populated with trees before it was heavily deforested in the 39th century. (PROSE: Frank Reade, Jr.'s Electric Time Canoe)
Poosh was either a famously lost moon or a planet that had famously lost one of its moons. (TV: Midnight) Part of the New Dalek Empire's stolen planets, (TV: The Stolen Earth) the celestial body was returned to its rightful place in the cosmos by Donna Noble. (TV: Journey's End)
Skaro had at least three moons Omega Mysterium, Flidor and Falkus, (AUDIO: Davros, Innocence, Purity) the latter of which hosted a Dalek facility where they imprisoned an alternate version of Davros during the Last Great Time War. (AUDIO: Restoration of the Daleks) In the Dalek Dome in 2323, the Daleks of the Golden City Zone sought to exit their simulation for the real world. To compute the calculations needed for such a transit, the Golden Emperor ordered the creation of a Mathematicians' Moon entirely populated by Quadruple-Brained Algebraists whose calculations sustained the quantum-powered reality gates. The Fourteenth Doctor managed to destroy this moon, ending the 2323 Dalek invasion of Earth. (COMIC: )
During the Time War, the Eternity Circle harvested three moons in the Tantalus Spiral as the foundation for their construction of a large scale version of the Temporal Cannon. (PROSE: Engines of War)
Villengard was orbited by a partially-destroyed moon. (TV: Twice Upon a Time)
The Library was orbited by the Doctor Moon, a sentient maintenance hub that tended to the mind of Charlotte Lux that ran the Library. (TV: Silence in the Library)
Vulpana had four moons, (AUDIO:The Moons of Vulpana) Domusalba being an inhabited one, politically separate from the planet it orbited. (COMIC: Hill of Beans)
==Other references==
"Moons of madness" was a curse sworn by the Captain. (TV: The Pirate Planet)
"By the moons" was an oath sworn by the Ice Warriors and those who did them honour, such as Clara Oswald and the Twelfth Doctor. (TV: Cold War, Empress of Mars)
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