From Battlestar Wiki, the free, open content Battlestar Galactica encyclopedia and episode guide
Mars Day is the name of a day in the Colonial calendar. It was named after the Colonial God of War (TRS: "Occupation").
- It is not clearly stated whether or not Mars Day is a specific holiday or just the name of a weekday. However, in "Caprica" the use of real-world day names is established and one similarly named holiday, Eros Day, is mentioned.
- The use of the name "Mars" is somewhat unusual in terms of Colonial relgious history. "Mars" is the Roman name of the Greek God of War, Ares. Colonials have been shown to usually use the Greek names of their deities. However, Jupiter and Mercury have been mentioned in other episodes as well.
- In French and other romance languages, the name for Tuesday derives from the latin "Martis dies" (literally, "Mars' Day"). The English name derives from "Tyr", the Norse equivalent of Mars.