the days of the week

[mellowtigger]

I already knew most of the explanation for our days of the week in English, but this YouTube video filled in some important details that I was missing.  Here's the short version of this history.

Humans long ago observed the stars and noted that some of them seemed fixed in the sky while others moved. The Greeks counted 7 heavenly bodies that moved, according to what they could see by naked eye in those days before light pollution. They called these objects the "wanderers", which in Greek is "planetes".

Assuming the Earth was the center of the universe, with the wanderers circling around us in their own spheres, the Greeks numbered those 7 bodies according to the duration of their cycle across the background of stars (also known as their sidereal period), from longest cycle to shortest.  Each of those wanderers was associated with a deity, whose names we'll list soon.

1. Saturn
2. Jupiter
3. Mars
4. Sun (1 year for it seemingly to circle back to its same position against the background of fixed stars)
5. Venus
6. Mercury
7. Moon

Around 3rd century BCE, Greek astrologers writing horoscopes in Egypt mysteriously decided that those gods in the sky ruled only once per hour during each day. Those 7 hours do not evenly divide into other time periods. If, however, they repeated those turns of 7 names for each hour of every day, then after 7 whole days, they did get back to their original starting position again. For instance:

Hour	Day 1	Day 2	Day 3	Day 4	Day 5	Day 6	Day 7	Day 8
1	Saturn	Sun	Moon	Mars	Mercury	Jupiter	Venus	same as day 1
2	Jupiter	Venus	Saturn	Sun	Moon	Mars	Mercury	"
3	Mars	Mercury	Jupiter	Venus	Saturn	Sun	Moon	"
4	Sun	Moon	Mars	Mercury	Jupiter	Venus	Saturn	"
5	Venus	Saturn	Sun	Moon	Mars	Mercury	Jupiter	"
6	Mercury	Jupiter	Venus	Saturn	Sun	Moon	Mars	"
7	Moon	Mars	Mercury	Jupiter	Venus	Saturn	Sun	"
...	...	...	...	...	...	...	...	...
24	Mars	Mercury	Jupiter	Venus	Saturn	Sun	Moon	"

Presto. The 7-day "planetary" week is formed.  Keep in mind that these "planets" are Greek wanderers in the sky, not what we call planets in astronomy today.

Even more historically interesting, though, is that each day took the name of the deity associated with that day's first hour. As Romans spread their calendar throughout Europe, we ended up with our current day-names.  Christians of Rome renamed 2 of the days, which continued with the Romance languages.  Norse pagans preferred the names of their local gods (keeping similar concepts as the Roman gods) for 4 of the other days, which continued with English (a language made from a bizarre mixture of Latin and German).

Day	Deity (Greek)	Astronomy (English)	Deity (Roman)	Day (Latin)	Christianity	Day (Spanish)	Day (French)	Deity (Norse)	Day (Old English)	Day (English)
1	Kronos	Saturn	Saturnus	Dies Saturni	"Sabbath"	Sabado	Samedi		Saeturnesdaeg	Saturday
2	Helios	Sun	Solis	Dies Solis	"The Day of the Lord"	Domingo	Dimanche		Sunnandaeg	Sunday
3	Selene	Moon	Luna	Dies Lunae		Lunes	Lundi		Monandaeg	Monday
4	Ares	Mars	Mars	Dies Martis		Martes	Mardi	Tiw/Tyr	Tiwesdaeg	Tuesday
5	Hermes	Mercury	Mercurius	Dies Mercuri		Miercolis	Mercredi	Woden/Odin	Wodnesdaeg	Wednesday
6	Zeus	Jupiter	Iovis/Iupiter	Dies Iovis		Jueves	Jeudi	Thor/Thunder	Thunresdaeg	Thursday
7	Aphrodite	Venus	Venus	Dies Veneris		Viernes	Vendredi	Frigge	Frigedaeg	Friday

As the 7-day week moved eastward, the Hindi and Chinese named their 7 days in the same order as the Greeks.

I do still have a few remaining questions.  I'm curious if the Greeks stole some of their ideas from earlier Egyptian astronomy, or if this repeating 7-hour concept started with them.  Some quick websearching provided me no answer.  I'm also curious about different cultures choosing different days as the start of their week, rather than Saturday.  I find lots of information, but all of it is as clear as the proverbial mud.  Anyway...

Happy Moon Day.