@urusan I was wondering, why is 7 days the number people agreed on for the most universal unit of time keeping around the world?
@csddumi
Good question. I suspect part of it has to do with the moon's cycle being 28 days long (or so I've been told), making a month, and 7 seems to be a reasonably small divisor of that to be the next lower level grouping of days. But at best that's only part of the answer, I think.
It's certainly true, that the 7 day week predates the solar calendars (Caesarian and Georgian) and thus probably relates to the lunar calendars.
@digital_carver another benefit of a theory like yours, is that lunar phases are almost universal all across the world, which would explain why this is not a unit generally disagreed upon.
@csddumi
Another thing that's true for India and maybe true for some other cultures too, is that there were thought to be 7 planets in the sky - Sun, Moon, Mercury, Venus, Mars, Jupiter, Saturn (the others weren't visible). And the days of the week are named after them in India. So maybe that's the other part of it - 7 also corresponded to the number of known "planets". And people probably postulated some kidn of significant relationship between the planets and the days of the week.