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.

Comments

[bitterlawngnome]

Most of the astronomy/astrology inherited by classical antiquity was anticipated in Babylon or its predecessors or neighbours (I say anticipated rather then developed cause we have no way of knowing if various cultures developed the same methods independently based on the same observations). https://en.wikipedia.org/wiki/Babylonian_calendar

[mellowtigger]

Great point. I suspect that the utility of a 7-day period was introduced to the Greeks. Why else would they "suddenly" figure this out in Egypt, apparently? But the Greeks were big on finding patterns in nature, supporting their ideas about the harmony of the spheres. They believed that reality was out there, understandable, and beautiful in its simplicity. They were probably responsible for connecting the 7-day week with the 7 wanderers in the sky and immediately noticed its compelling synchronicity, even as they abandoned faith in actual gods in the sky.

The piece I was missing until now was the names of the first hour of the day, based on the sidereal period of those 7 wanderers. That beautiful Greek symmetry is probably why these days and in this order swept the globe. It's amazing. I'm slightly sad that this history is not taught in schools.

[mellowtigger]

... assuming that it's accurate rather than just plausible. I saw it on YouTube, so... you know.

[zipperbear]

My impression is that dividing days into 24 hours is just arbitrary. Babylonians liked 12 and 60, because of all the factors (2, 3, 4, 5, 6). The quarters of the moon are easily visible, and they affect the tides and the amount of moonlight, so having approximately 4 weeks of 7 days each seems natural and appealing, similar to the roughly 12 lunar months per year. It adds the next integer into the mix.

The fact that 7 is relatively prime to 12 or 24 means any counting of hours in patterns of 7 will repeat every week. That pattern is aesthetically pleasing, but it seems like a contrived way to name the days of the week. I think the Babylonians or other sky-watchers came up with some astrological patterns, and presumably their names caught on with Hellenic tribes, who liked that science-y stuff. Today, the day-names are learned by rote, and they're marginally recognizable as planets or gods, and it's been that way since the Romans copied the Greeks.

The start of the week is also arbitrary, and the shift of Jewish sabbath on Saturday (and Friday night) to Christian Sunday as The Lord's day seem inexplicable to me (and to the Seventh Day Adventists, too), but I guess that's why there's a 2-day weekend, to make sure you get the right day of rest.

Much of the world also just numbers the days of the week, which seems just as easy, except that there's no agreement. My favorite is Swahili, with consecutive day names, one Bantu-derived, the next one Arabic-derived, both meaning "5th day":
https://en.wikipedia.org/wiki/Names_of_the_days_of_the_week#Days_numbered_from_Saturday

I'll just keep using the English day names and the American MM/DD format. And they'll pry the Fahrenheit out of my moderately lukewarm hands.

[mellowtigger]

I've been intending to reply more thoughtfully to your comment, but recently... *gestures at world* and for at least another week... *gestures at world again*.

As a techie, I very much prefer a year-month-day format because then numbers automatically sort chronologically when you sort alphabetically. I have other thoughts about what I call "anthropic" (human-centric) calendar and temperature, but that writing will have to wait for saner times.