The Sky Tonight Update: Supermoon #3, Dec. 14
December 14th will bring the third and last of what is known as the “supermoon.” The Moon will be located on the opposite side of the Earth as the Sun and its face will be will be fully illuminated. This full moon was known by early Native American tribes as the Full Cold Moon because this is the time of year when the cold winter air settles in and the nights become long and dark.
The third supermoon has also been known as the Full Long Nights Moon and the Moon Before Yule. This Moon will be at its closest approach to the Earth and may look slightly larger and brighter than usual.
The term supermoon has entered popular consciousness in recent years. Originally a term from modern astrology for a new or full moon that occurs when the moon is within 90% of its closest approach to Earth in a given orbit, supermoon now refers more broadly to a full moon that is closer to Earth than average. But why is the moon closer to Earth at some times but not others?
The supermoon of December 14 is remarkable for a different reason: it’s going to wipe out the view of the Geminid meteor shower. Bright moonlight will reduce the visibility of faint meteors five to ten fold, transforming the usually fantastic Geminids into an astronomical footnote. Sky watchers will be lucky to see a dozen Geminids per hour when the shower peaks.