A seven day week can be a nightmare. But nature runs every minute, every hour, without breaks. That’s nature’s nature !.

The incongruity between the civilized man and the nature seems to be growing with every minute, but the question I want to ask here is a historical one — why do we have a seven day week ?

Why not a 4 day paradise or 9 day hell instead. Well, there was a time when people tried to create such things. These were the times when civilizations bloomed for the first time and experiments were done on very simple aspects. One can find those experiments in scriptures.

If you think that seven days are a result of 7 celestial bodies, then that is a wrong assertion, and unfortunately it is extremely popular. As we would find out that most ancient cultures had 9 celestial bodies. The extra two being — south and north lunar nodes.

Celestial bodies are used to serialize the 7 days of the week. We can say this because, the days of the week have no relation with the movement of the planets in the night sky. The assigning of days to a particular planet is a later invention.

In fact the Ancient Vedic system (as well as the Babylonian system) has a serializing logic to explain why “Sun”day is followed by “Mon”day. And that serialization has no astronomical basis.

So…

Why do we have a seven day week ?

The idea of seven day week is rooted in the motion of the moon.

Moon has two characteristics that caught the attention of our older selves—

1) Movement across the sky (revolution around the Earth).

2) Phases.

The first one got us a sidereal month that has 27.3 days.

The latter gave us a synodical month that has 29.5 days.

The concept of month is derived from the synodical bit. The word month itself comes from moon . The Sanskrit word Maas and its Persian derivative Mahina both are derived from the word “moon”. A month is the time period between successive full moons or successive new moons. This period which is 29.5 days is called a month. How the Gregorian calendar made it 30/31/28, is another story.

Asterism (not the religion of Asterix)

The concept of Nakshatra (Indian lunar asterisms) is derived from sidereal month.

Just like the Sun’s path is divided in 12 equal parts, known as Zodiacs. Moon’s path is divided into 27 equal parts known as Lunar Asterisms. Since Moon takes 27 days to complete the whole cycle, it stays in one Asterism for one day.

That’s pretty neat.

This is the reason why Moon has 27 wives in many mythological systems, he is notorious for being a philanderer. Lucky moon.

The Zodiac (not the movie)

The Zodiacs are human artefacts, they are neither supernatural nor have characteristics intrinsic to them. They are the milestones of a magnificent time keeping system. A system that we modern humans still use today (12 months of 30 days each).

If the synodical cycle of moon is visualized in a circle, it will have two extremes and two means. The two extremes being new moon and full moon. The means being two half moons. This makes 4 quadrants within a month.

Each quadrant is a week.

Weak by week

If we consider both these cycles — synodical and sidereal — it makes a mean time of 28 days. Something that could be conveniently divided into 4 parts of 7 days each.

Now, it is pretty clear why week has 7 days.

Seven. Both Sapta and Hapta mean seven. The Greek and Latin words Sept (as in September) and Hept (as in Heptagon) are versions of Sapta only.

The word for week in Persian is Hafta. Something that derives from Avestan word Hapta. While the Sanskrit word for seven is “Sapta”, which is also, the Indian word for week.

It is a coincidence that moon’s rotation and revolution cycles take approximately the same time.

A coincidence that makes only one hemisphere of the moon available for our gaze. Something that became the epitome of beauty.

And as always,

Stay beautiful,

Stay awesome.