Why 7 days a week?

Question

I was wondering why do we have 7 days a week? and not have like 10 days? or 2?

Answer 1

It comes from the moon.  The moon has a twenty-eight day cycle.  In this ancient diagram, notice the moons around the border.  Start at the top with the full moon.  Count down seven days or seven moons to the half moon.  Count seven more days to the blacked out moon.  Count seven more days to a new half moon.  And seven more days back up to the full moon.  The seven day week is the lunar month divided into four demarcations, full moon, half moon, full blacked out moon, new half moon.

http://yogini.files.wordpress.com/2007/0...

http://www.scde.k12.tn.us/chms/jaz/moon....

http://aa.usno.navy.mil/graphics/Moon_mo...

Answer 2

Well its because theres 365 days a year so they split it into 12 groups (months) then put 3 1/2 weeks in each monthes and in fit for 7 days in each week.

Answer 3

I  happen to know this, because a student asked me this question not too long ago and I had to go find out.  There are a lot of answers that don't make sense and there's one that just hit the nail on the head.

The thing about this phenomenon is that so many (not all) different cultures adopted a 7-day week.  It is very widespread, and many, many of the cultures that have the 7 day week could not possibly have gotten it from the Hebrews or other semitic cultures.

The answer is that people typically named their days after astronomical objects.  Our current week immediately shows us this -- Saturday, Sunday and Monday represent the sun and moon and the planet Saturn.

The naming was done at a time when there were 7 visible transient objects (not including stars, of course) in the sky -- the sun, the moon, and the 5 visible planets (Mercury, Venus, Mars, Jupiter and Saturn.)  The week was 7 days long because that's how many names they had for days.

When you think about it, it makes sense.  The other theories suggest why the week is a particular length, but this theory goes further and explains why we have a week at all.  A year and a month have clear astronomical bases -- one related to solar cycles, the other to lunar.  But why did people feel compelled to invent the time period known as the week?  It's only because they had names for seven days.

Or, of course, some people say it's because God created the earth in 6 days + 1 day of rest.  You can always use that theory if you're satisfied with it.  It requires you to assume that a lot of those cultures forgot about the Hebrew God but remembered the length of their week.  I think that's a bit of a stretch.

Answer 4

or ..    you can just think that time doesn't exist ..

and its really just mans greatest invention

Answer 5

The origin has to do with farmers in a market economy, not astronomy, which was applied to it later.

The first thing to understand is that a week is not necessarily seven days. In pre-literate societies weeks of 4 to 10 days were observed; those weeks were typically the interval from one market day to the next. Four to 10 days gave farmers enough time to accumulate and transport goods to sell. (The one week that was almost always avoided was the 7-day week -- it was considered unlucky!) The 7-day week was introduced in Rome (where ides, nones, and calends were the vogue) in the first century A.D. by Persian astrology fanatics, not by Christians or Jews. The idea was that there would be a day for the five known planets, plus the sun and the moon, making seven; this was an ancient West Asian idea. However, when Christianity became the official religion of the Roman empire in the time of Constantine (c. 325 A.D.), the familiar Hebrew-Christian week of 7 days, beginning on Sunday, became conflated with the pagan week and took its place in the Julian calendar. Thereafter, it seemed to Christians that the week Rome now observed was seamless with the 7-day week of the Bible -- even though its pagan roots were obvious in the names of the days: Saturn's day, Sun's day, Moon's day. The other days take their equally pagan names in English from a detour into Norse mythology: Tiw's day, Woden's day, Thor's day, and Fria's day.

Answer 6

Because thats the way God made it.