Mercury
Mercury is the closest planet to the Sun, and is also the smallest in our solar system ever since Pluto was demoted to dwarf planet status.
It has been known since at least the 14th century BCE when its movements were recorded by an Assyrian astronomer.
The name Mercury comes from Mercurius, the fleet footed Roman messenger god. In Ancient Greece one of the planet’s names Hermes (Ἑρμής), the Greek analogue of Mercury.
Interestingly the Babylonians also named the planet after their messenger god, Nabu.
Fun fact: In old Germanic mythology, the planet was associated with the god Odin. The Old English name for Odin was Woden, for whom the middle day of the week was originally named Woden’s Day, which has now morphed in Wednesday.
Header image: Mercury Shows its True Colors by NASA