# Theodian calendars

This article details the current official calendars of the Technocratic Republic of Theodia. The information herein was current as of November 2020.

## Formats

Dates are formatted as follows: `YYY:MM:DD T.TTͲ`. So, the date `2010-04-22T12:00` is `223:04:12 2.00Ͳ`. Years before the current epoch are negative numbers: `-0752-04-21` (21 April 753 BCE, the founding of Rome) is `-833:04:19`.

• Colons are used instead of dashes or slashes, since they generally lack mathematical meaning, and since their non-mathematical meaning (that additional information is to follow) is applicable in this circumstance.
• Weeks aren't written separately in the way that months are, as it is easy to tell what week a number is in by glancing at it, since the week length (six) is a divisor of the base (twelve).
• Time in this example is written with Sampi (Ͳ) because this example is in the Earthling Calendar, which uses radial Ergonometric time.

## Standards

• Wherever reasonable, planets will have their own local calendars.
• There will be a default, universal calendar.
• There will be a reference calendar that will function as a simple API to facilitate conversion between different calendars.
• Calendars' epochs should be based on when the current civilization began in a given locality. In calendars for which there cannot reasonably be any such thing (such as in space), the epoch should use the reference calendar's.
• Days on planets with day-lengths close to the human circadian rhythm will use percentages instead of hours, minutes, and seconds. (aka, radial Ergonometric time)
• Days elsewhere will use the average length of the human circadian rhythm. (aka, linear Ergonometric time)
• Weeks are 6 days long.
• Months should be between 24 and 36 days.
• Years should be no longer than 768 days.

## Calendars

### Reference

To solve the problem of exponential relations between different calendars while minimizing computational complexity, Theodia has adopted the time elapsed since the UNIX Epoch (including leap seconds) as its reference calendar. All other Theodian calendars, in order to be converted into another, must first be converted to this reference calendar.

While the UNIX Epoch (`1970-01-01T00:00:00-00:00`) is fundamentally arbitrary, there's no point in having an idiomatic epoch for what is, essentially, an API in the form of a calendar; and so, the choice of epoch here is almost necessarily arbitrary.

### Default

Localities under Theodian control that do not have their own dedicated calendar, default to using the Default Calendar. The Default Calendar, detached from physical restrictions, aims for mathematical regularity. This makes it very convenient to use, and the preferred calendar for those living in space away from any heavenly body, and also for those living on or near a heavenly body with very alien natural cycles, such as Venus and Uranus. It is also preferred in the sciences, and used by the national government of Theodia as its primary calendar.

It is descended from the older Universal Calendar.

In the Default Calendar, a day is approximately 24 SI hours and 11 SI minutes in length (per research into the length of the human circadian rhythm by Czeisler et al.[1]). Months are each exactly 6 weeks, making each month a perfect square. Years are 100twelve (144ten) days, thus making exactly 4 months per year. There are no leap seconds, days, weeks, etc. The calendar starts from `2010-04-22T12:00:00-04:00`, the date Theodia was founded.

### Earthling

File:Th Kalendar Example.png
An example of an Earthling Theodian year in relation to a Gregorian year

Localities under Theodian control that are located on or near the Earth use the Earthling Calendar. This calendar syncs with many of Earth's natural cycles, and turned out to be fairly similar to the existing Gregorian calendar.

In the Earthling Calendar, a day is exactly 1 SI day, including leap seconds where necessary. Months are each 5 weeks long, making for 26twelve (30ten) days per month, total. Years are 10twelve (12ten) months long. This leaves 5 days (plus one leap day) unallocated; these are divided among the cardinal months: extra days for the months before each solstice and equinox, preferring solstices. As the northern hemisphere is by-far the most-populated, its winter solstice gets preference over the southern hemisphere's, for extra days (Intercalary days are, in Theodia, typically used for celebration; and it is better for productivity to have longer celebrations in Winter than in Summer.).

The calendar starts from `535-01-01T00:00:00-11:00`, which is the moment the year 535 started at the Florence Antimeridian. The year 535 is at the beginning of the Dark Ages, and symbolizes the "moment" at which the world of antiquity came to its end, and the stage for the world of modernity was set[2]. This epoch will be offset by around -12,000 years once there is an internationally agreed-upon start to the Anthropocene.

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