YM COLUMN ARCHIVE

September 17, 2008

The order of planets vs. days of the week

The other day I was asked a question at certain primary school, “Why is the order different between planets alignment and days of the week?” This was the fifth time asked of the same question since ten years ago at Q&A School on Space for children or somewhere else last time. I had quite a trouble in answering the question, because unfortunately I didn’t have slides ready and no whiteboard available there.

A day was already set twenty-four hours in the days of ancient Babylonia. On assumption of a given fact that this figure of twenty-four is related to the signs of the zodiac, I will proceed to the story of days of the week.

As you may know quite well, in earlier days the planets were only known as Mercury, Venus, Mars, Jupiter and Saturn. In those days earth was believed to have been a center of universe, so sun and moon were also considered in the group of planets. The alignment was believed, in order of farther to nearer, “Saturn, Jupiter, Mars, Sun, Venus, Mercury and Moon”. Having looked up at night sky to find that those planets moved different from the fixed stars, they called them “wandering stars” or “planets” and visualized them as “God is patrolling”, which is quite understandable.

Moon was believed to take a round in twenty-eight days and periodically came to new moon, first quarter moon, full moon, last quarter moon and back to new moon, of which interval was seven days respectively. This fact on moon and other fact of seven planets might have led them to presume that the number of “seven” on both facts were not just coincident, as they were preoccupied in the thought that they were all controlled by the heaven. A cycle period of seven days was invented and interpreted each day was alternatively controlled by different gods of planets.

The first day was the day entirely controlled by the farthest planet, Saturn. On this day, the first hour (0~1) was controlled by Saturn, the second hour (1~2) was in charge of Jupiter, the third (2~3) was by Mars and so forth; the twenty-fourth hour eventually came to be in charge of Mars. The next day’s first hour turned to Sun, so the second day is the “Day of Sun” to control whole day. Likewise, if to allot the first hour to Sun, the second to Venus and the third to Mercury, and then the twenty-fourth turned to Mercury, which made the third day the “Day of Moon”. Thus the order of days of the week was made “Saturday-Sunday-Monday-Tuesday-----Friday”.

Incidentally, the Judah Kingdom was overthrown in B.C.586 and Jewish people were confined in Babylon so-called “Babylon captivity”, after which they were liberated at last in B.C.538 and established the religion “Yahveh, the one and only God”. In opening Genesis of the Old Testament of the authentic scripture is written “God created the world in six days”. On the first day God created light and darkness, water and heaven on the second day, land and plants on the third day, Sun, Moon and Stars on the fourth, fish and bird on the fifth, animal and human on the sixth. God made the seventh day the Sabbath as a sacred day. Seven days were a cycle period.

And Law of Moses ruled to entirely refrain from working and keep praying on the day of rest once in a week. The day of rest was named the “Sabbath”, which is, in a present term, from Friday sunset to Saturday sunset. Thus “the day of Sun” was called “the first day of Sabbath”; “the day of Moon” as “the second day of Sabbath”; “the day of Mars” as “the third day of Sabbath”. On the last day of the week came “the day of Saturn”, the rest day.

There is more to it. Greece basically followed the rule but Constantine the Great in Roman period recognized Christianity by Edict of Milano in 313. On this occasion, with regard to the fact that Jesus Christ was crucified on “the day of Venus” and resurrected on “the day of Sun”, they made “the resurrection day” as “the day of Christ” namely “the Sabbath”. The Sabbath became “the day of Sun” under Christianity from “the day of Saturn” of Judaism.

There are two ways of calling days of the week in Europe. In Eastern Europe they call it by the number like the first day, the second day and so on except the Sabbath by the ecclesiastical system of Juda-Greek church, while in Western Europe they call it by the name of planet in Roman way of planetary system.

In the last place, I will make a list of Roman way as follows:

Sunday            dies Solis          the day of Sun
                         dies Dominica  the day of the Mater

Monday           dies Lunae         the day of Moon

Tuesday           dies Martis        the day of the mighty God of war                                                          (Mars in Greece, too)

Wednesday     dies Mercurii     the day of Mercurius, God of trade                                                         (Hermes in Greece)

Thursday          dies Jovis          the day of Jupiter, King of Gods                                                         (Zeus in Greece)

Friday               dies Veneris     the day of Venus, God of love and                                                        beauty
                                                     (Aphrodite in Greece)

Saturday           dies Saturni      the day of Saturnus, God of                                                      agriculture
                                                     (Cronos or Cronus in Greece)

I welcome your opinions on this column to the following E-mail address.
matogawa@planetary.or.jp