The gods that the weekdays are named after also have associated planets, so really every day is named after a celestial body already.
Ex: Saturday is obviously Saturn Day, Thursday is Thor’s Day, with Thor being the equivalent of the Roman Jupiter, so Thursday is indirectly Jupiter Day, etc.
Sunday and Mo(o)nday are named after celestial bodies. Is astronomy not scientific enough for you?
The gods that the weekdays are named after also have associated planets, so really every day is named after a celestial body already.
Ex: Saturday is obviously Saturn Day, Thursday is Thor’s Day, with Thor being the equivalent of the Roman Jupiter, so Thursday is indirectly Jupiter Day, etc.