What is the origin of the Seven-Day Week?


Specific Question:





Re: Equinox


Sat, 25 Feb 2006 19:12:10 -0600

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Thank you for a quick reply, I'll try to make my question clearer.


If we count from "noon" to "noon" a day, and count from equinox to equinox as a year, how many days will be in a year ? Also, the answer would have to be in whole numbers.


My two sons and I are working on a project trying to figure out how

the ancients came up with a seven day week.




This is not an easy question to answer. A seven-day week does not fit evenly into a 52-week year.


A year includes 365 solar days, except during a Leap Year when there are 366 full solar days. How these days of the year are divided into weeks (and months) was probably partly due to politics of the ancient era (specifically Roman politics, in the case of months).


One seemingly obvious answer is that a seven-day week was proscribed by God, in the account of creation from the Book of Genesis in the Bible. However, it seems that the seven-day week was known before Christianity became the dominant religion in the world.


Here is a short essay regarding the question of the origin of the seven-day week:


< http://webexhibits.org/calendars/week.html#SECTION00610000000000000000 >


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††††††††††††††††††††††††††††††††††††† < FAQ@planetarium.cc >.
Editorís Note: This astronomically-related question was answered by Glenn A. Walsh, who served as
Astronomical Observatory Coordinator and a Planetarium Lecturer at Pittsburghís original
Buhl Planetarium and Institute of Popular Science in the late 1980s and early 1990s. Mr. Walsh also served as a Life 
Trustee, on the Board of Trustees, of the Andrew Carnegie Free Library and Music Hall in Carnegie, Pennsylvania in the 
late 1990s, including one year as the Libraryís Treasurer.
Today, Mr. Walsh is Project Director of a not-for-profit organization, Friends of the Zeiss, which works for the 
preservation and continued functionality of the historic equipment and artifacts of a
pioneer in the history of the development of planetaria and museums of the physical sciences, Pittsburgh's
Buhl Planetarium and Institute of Popular Science, including the Zeiss II Planetarium Projector,
now the oldest operable major planetarium projector in the world !
Glenn A. Walsh
Electronic Mail - < gawalsh@planetarium.cc > 
Author of History Web Sites on the Internet --
* Buhl Planetarium, Pittsburgh: 
††< http://www.planetarium.cc > 
* Adler Planetarium, Chicago: 
††< http://adlerplanetarium.tripod.com >
* Astronomer & Optician John A. Brashear: 
††< http://johnbrashear.tripod.com > 
* Andrew Carnegie & Carnegie Libraries: 
††< http://www.andrewcarnegie.cc > 
* Duquesne Incline cable-car railway, Pittsburgh: 
††< http://www.incline.cc >

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