Does a Martian calendar need weeks, or other units between day and year?
There is no astronomical cycle on Mars that corresponds to our idea of a week. This is also true on Earth, although the seven-day week may have been originally suggested by the principal phases of the Moon: new moon, first quarter, full moon, and last quarter. The Romans had an eight-day market cycle, but also divided the month into three unequal periods called the Calends, the Nones, and the Ides. The Aztecs had a 13-day cycle.
Pro The number 6 is divisible by 2 and 3. An even number of days makes it easier to plan things every second day (the joggers argument). Con Source Documents: Elemental Martian CalendarsTerry Phelan A Timekeeping System For MarsBen Weiss
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Pro This system retains the week as used on Earth. Attempts in the 18th and 20th centuries to promulgate calendars based on weeks other than 7 days quickly failed. Con The number 7 is prime, making division of the week into smaller units problematic. Source Documents: Time Measures on MarsRobert G. Aitken A Mars Proleptic Calendar and Sol-Date Timing ReferenceMichael Allison Arih Martian CalendarIgor Arih Arihrov Marsovski KoledarIgor Arih Seasons on MarsFrank N. Bauregger A Thought for the FutureWilliam H. Becker The Darian Defrost CalendarFrans Blok The Rotterdam Month and Weekday Naming SystemFrans Blok Waar blijft de tijd op Mars?Frans Blok Mars CalendarBlort Martian TimekeepingGeoffrey Briggs and Howard Houben Simplest Possible Mars Calendar Used in the Novel As It Is On MarsThomas W. Cronin Time Keeping on MarsAlan Dechert 600-Year Martian CalendarAlan Dechert Excerpts from Martian RainbowRobert L. Forward The Darian SystemThomas Gangale The Millennium Mars CalendarJames M. Graham and Kandis Elliot Excerpts from Mars UndergroundWilliam K. Hartmann An Easily Understood Calendar and Time System for MarsLeon G. Heron Rationale for the Martian Calendar's StructureBill Hollon A Four Season Split-year Calendar for MarsPeter Kokh The "Mars Pulse" CalendarPeter Kokh Space Studies 200 Group ProjectRyan Kramer et al. Martian CalendarRoger E. Kuiper SCDTL Calendar and Clock for MarsLance Latham It's About TimeI. M. Levitt Mars Clock and CalendarI. M. Levitt Excerpts from The Greening of MarsJames Lovelock and Michael Allaby The Utopian Calendar Mars Time Group The Areosynchronous CalendarShaun Moss The Kepler CalendarShaun Moss Martian Dreams Time SystemLinda Naughton and Robert O'Meara Elemental Martian CalendarsTerry Phelan Le Calendrier MartienOlivier Prud'homme Calendar for MarsRobert S. Richardson Excerpts from Red MarsKim Stanley Robinson Salvas Calendar System for MarsKeith Salvas Time on MarsJohn J. G. Savard Martian Clock and CalendarMickey D. Schmidt Calendario en MarteMiguel Angel Serra Martín Mars CalendarMiguel Angel Serra Martín Martian TimekeepingAnders Ström A Calendar for MarsJosef Šurán A Mars CalendarRichard Weidner Options for Martian TimekeepingWilliam Woods
Pro The number 8 is divisible by 2 and 4. An even number of days makes it easier to plan things every second day (the joggers argument). Con Source Documents: Calendar for MarsMike Kretsch
Pro The number 9 is divisible by 3. Con Source Documents: Further Thoughts on VophicismMark Knoke Towards a Better Martian CalendarMark Knoke
Pro The number 10 is divisible by 2 and 5. An even number of days makes it easier to plan things every second day (the joggers argument). Being a decimal system, converting between number of days and number of weeks is a simple matter of moving the decimal point. Con Source Documents: The Thothian WheelFred Hightower The Martian Calendar M. Vertregt Martian Year RevisitedM. Vertregt and Francis Graham
Pro Months and weeks do not make sense for the planet Mars since there is no comparable influence of a large Moon around Mars. Con The measurement of time is more than a matter of astronomy. At its core, it is a matter of human needs. There is a demonstrated sociological need for a time cycle in the range of five to ten days, with certain days set aside for worship, rest and recreation, and specific work tasks. Nearly every culture on Earth has devised such a unit of time. Since numbering "the days straight through from 1 to the end of the year" as the primary method of reckoning time has never served the needs of any human culture to date, it probably will not do so in the future either. It ought to be obvious that organization requires grouping together a manageable number of similar items in a hierarchical structure. Examples of this principle are everywhere. Humans have a basic need to organize their world--any world--into relatively small numbers. This aspect of human nature points up the necessity of organizing the Martian year into months, and the months into weeks. The requirement for weeks on Mars can be supposed to exist, and furthermore, it cannot reasonably be supposed NOT to exist, because the basic needs of human organization remain the same. We can suppose sub-units of the year to exist, simply because 669 is too large of a number to use as a basis for organization. The fact that there is no comparable astronomical cycle to the week on Mars is not relevant. What is relevant is that there is no astronomical cycle on Mars that conflicts with it. This allows us to import this humanly indispensable unit of time to Mars with no trade-off, no down side. Source Documents: Calendrier Martien du GCMFrançois Forget et al. Excerpts from Across the ZodiacPercy Greg A New Calendar and Clock for the Planet MarsManfred Krutein The QS Calendar Jelmer Oosthoek
Since numbering "the days straight through from 1 to the end of the year" as the primary method of reckoning time has never served the needs of any human culture to date, it probably will not do so in the future either. It ought to be obvious that organization requires grouping together a manageable number of similar items in a hierarchical structure. Examples of this principle are everywhere. Humans have a basic need to organize their world--any world--into relatively small numbers. This aspect of human nature points up the necessity of organizing the Martian year into months, and the months into weeks. The requirement for weeks on Mars can be supposed to exist, and furthermore, it cannot reasonably be supposed NOT to exist, because the basic needs of human organization remain the same. We can suppose sub-units of the year to exist, simply because 669 is too large of a number to use as a basis for organization.
The fact that there is no comparable astronomical cycle to the week on Mars is not relevant. What is relevant is that there is no astronomical cycle on Mars that conflicts with it. This allows us to import this humanly indispensable unit of time to Mars with no trade-off, no down side.