February 27, 2020
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Quarter and Day

Basti93 / Pixabay

The vast majority of world calendars have twelve or thirteen months, as the original base of most calendars were related to the cycles of the moon.

The Earth Epic Calendar has based itself on factors of one hundred, but this gets tricky with a year that has 365 or 366 days per year. However, if we divide the year into equal quarters, we get 91 or 92 days each, which is close to 100.

A big advantage of this set up is that since every quarter has about thirteen weeks, it makes it easier to use the calendar to plan weeks ahead of time without having to turn the calendar page. It’s worth noting that this setup is similar to the World Seasons Calendar proposed by science fiction writer Isaac Asimov. It should also be noted that due to the elliptical nature of the earth’s rotation, the lengths of the astronomical seasons vary from the quarters described in this calendar—astronomical spring, summer, fall and winter currently vary in length between 88-93 days.

(Something else that is noteworthy, but not essential knowledge for this calendar.  If you were to multiply 4 (for the quarters per year) times 25 (for the number of millenia per epoch), you’d get one hundred. That would mean 100,000 quarters per epoch. If you really wanted to, you could skip the units of year and millenium and set up units at, say, 1,000 quarters–a kiloquarter– with 100 kiloquarters equalling an epoch.  But the year is a unit that every calendar in the whole world has been using for millenia, and changing that would likely create more problems than it solves.)

However, unlike Asimov’s calendar, the first day of the year is not tied to a specific date on the Gregorian calendar but set at the precise day of the astronomical winter solstice in the Northern Hemisphere. On the Gregorian calendar, this day is currently either December 21 or 22. This makes for a more accurate calendar.

This is modeled after the Solar Hijri calendar used in Iran and Afghanistan, which sets its new year at the precise day of the astronomical spring equinox. This–and not the Gregorian calendar, you Eurocentrists–is the most accurate calendar currently in use in the world. Both calendars and this one have 365 day regular years and leap years with 366 days. The Gregorian calendar sets its leap years at regular four year intervals, with exceptions made for years ending in 00 where the century is not divisible by four (i.e. 1700, 1800, 1900, 2100). However, by simply tying the first day of the year to the actual day of the winter solstice, the calendar never varies more than about a half day from the actual completion of one Earth orbit around the sun.

This, however, means that the incidences of the leap year are slightly more irregular than the Gregorian Calendar. Most of the time four years pass between leap years, but occasionally the interval is five years. In the Earth Epic calendar, the last leap year was 11.717 (starting on 12/21/2016) and the next one will be on 11.721 (starting on 12/21/2020). The last five year interval between leap years was between 11.708 and 11.713 and the next one will be between 11.741 and 11.746.

The Earth Epic Calendar sets the first day of the year at the Winter Solstice (rather than the Solar Hijri’s Spring Equinox) for several reasons. First, the adjustment from the Gregorian Calendar—the mostly widely used calendar in the world—is less difficult because the first day of the year in the Earth Epic calendar is just 10 or 11 days before the first day of the year in the Gregorian calendar, making adjustments easier. The Winter Solstice also coincides with holidays for many religions and cultures. This time is also often the midpoint between the autumn harvest and the spring planting season for much of the world, given that 90% of human beings live in the Northern Hemisphere.  This period around the Winter Solstice is often a time for reflection.

Most calendars assign names to months. I think local cultures should name the quarters in this calendar however they wish.  I spoke before as to how the worldwide adoption of the Gregorian calendar is a reflection of cultural imperialism.  Letting local cultures name the quarters would be a way to let them reclaim the calendar while still providing accuracy and uniformity of standards worldwide.

Even though local cultures should determine the name of the quarters as they deem appropriate, a worldwide standard would be helpful so that different cultures would have a common frame of reference as needed.  Referencing the quarters by using numbers could be a bit confusing, because four is a deviation from the decimal system we have been using.

For this worldwide standard, the names Southlight, Eastlight, Northlight and Westlight describe the Northern Hemisphere’s winter, spring, summer and fall (and the Southern Hemisphere’s summer, fall, winter and spring). The first day of Southlight (and the first day of the year) starts at the December Solstice when the concentration of sunlight is greatest and at its peak in the Southern Hemisphere, and Northtide starts around the June Solstice when the concentration of sunlight is the greatest and at its peak in the Northern Hemisphere.

Eastlight and Westlight both start close to the March and September equinoxes.  While Southlight and Northlight reference the Sun’s position relative to Earth, Eastlight and Westlight are more metaphorical when referencing the Sun’s position.  Since the Sun hits the Eastern Hemisphere first on the rotation of any given day before going to the Western Hemisphere, the metaphor will be extended to naming the first equinox Eastlight (in March) and the second equinox Westlight in September. The Northern Hemisphere spring rises in the east and its autumn sets in the west.

Since four quarters of 91 days equals 364, we need to figure out where to put the extra day so that the year totals 365 days, and where to put the leap day during leap years.  Asimov’s calendar puts the extra day at the end of the year and the leap day at the end of the second quarter.  But in the Earth Epic Calendar, each year has an extra day at the end of Northlight (the summer, or third quarter of the year), during September in the Gregorian Calendar.  During leap years, an extra day is added to the end of Eastlight (roughly the spring, or second quarter of the year), during June in the Gregorian calendar.

Why these times?  It’s because the Earth’s orbit around the sun is elliptical, rather than a perfectly round circle with the Sun in the center. Currently, summer in the Northern Hemisphere is the longest season, followed by spring in the Northern Hemisphere.  Consequently, the Earth Epic Calendar adds a day most often to the quarter covering the Northern Hemisphere summer–Northlight, and the leap year day is added to the end of Easttide during leap years.  This keeps the length of the quarter close to the length of the astronomical season.

Axial precession and leap days
Impact of Earth’s axial precession and elliptical orbit on the lengths of seasons.
Image By Cmglee – Own work, CC BY-SA 3.0, https://commons.wikimedia.org/w/index.php?curid=30359851

It is worth noting that the date where the extra day and leap day are assigned will change four times per Calendar Epoch, or roughly every 6,500 years.  This is because the length of astronomical seasons change due to the axial precession.  As such, autumn will be the longest season, with summer being the second longest, around 7000 CE (16.700 EE), which will necessitate placing the extra day at the end of Westlight (in December) and the leap day at the end of Northlight (in September).  Winter will be the longest season around 12,000 CE (21.700 EE) which will necessitate putting the extra day at the end of Southlight (in March) and the leap day at the end of Weslight (in December).



The Earth Epic Calendar has seven-day weeks primarily to accommodate spiritual requirements of Judaism, Christianity, Islam, and other religions that worship on a seven-day cycle.

The Earth Epic Calendar has its own names for the days of the week in order to appeal to the widest number of religions possible. Since Friday, Saturday, and Sunday are holy days for Islam, Judaisim and Christianity respectively, the days are named Islamica, Judaica, and Christianica accordingly. The remaining four days are named after what are regarded as four essential elements by Buddhism and many indigenous religions of Asia, Europe, and North America. As such, Monday, Tuesday, Wednesday, and Thursday are referred to as Waterday, Earthday, Windday, and Fireday respectively.

In most years, three out of the four Quarters have ninety-one days (this is two out of four Quarters during leap years). Because 91, unlike 30 or 31, is evenly divisible by seven, the first day of each Quarter will start on the same day of the week. Because Northlight for the next 5,000 years will have 92 instead of 91 days, Westlight 0 will fall one day of the week forward from Northlight 0. Day 0 of each Quarter will then fall on the same day of the until the next Westlight 0 unless the next year is a leap year. Since Eastlight currently has an extra day during leap eyars, the Northlight 0 following the leap day on the last day of Eastlight will fall also one weekday forward from previous Quarters. Then the next Quarter, Westlight 0 will fall one weekday forward from Northlight as usual, meaning that it will begintwo weekdays forward from the previous Westlight.

It will be up to future generations to decide whether to continue with a seven-day week. The seven-day week is not inherently critical to the structure of the Earth Epic Calendar. Such a system exists to accommodate conditions as they exist in the early 3rd millennium CE/mid- to late Millenium 11 EE.

Instead of seven day weeks, one option would be to divide the quarter into roughly nine units of ten days each.  As such, it would not be necessary to even have days of the week, as the last digit of the date would be sufficient to determine the day of the week.  This was tried during the French Revolution, but was unpopular largely due to laborers only getting 1 1/2 days of rest out of 10.  The current five day work week means that 28.5% of the week is set aside for rest (though, unfortunately, many workplaces require six and even seven days of work per week.)  A strong argument could be made for having three or even four out of the ten days being set aside for rest and recreation.  But this is for society to decide for itself in the future.

It’s worth noting that while the average length of the year has been quite constant over most of Earth’s history, the length of days has changed significantly.  Roughly 250 million years (1 eon) ago, the length of the day was about 23 hours and 500 million years ago (2 eons), the length of the day was about 22 hours.  With the orbit of the earth around the sun being about the same length of time, that means that a year consisted of about 380 days one eon ago and nearly 400 days two eons ago.  Accordingly, the length of the year will be about 350 days one eon from now.  A change of just one day per year changes our calendar, so truthfully, actual calendar dates more than a million years before or after the present time would not be accurate with today’s calendar.  As such, there is no point in using the quarters, days or smaller units in this calendar for any date over a million years in the future or past.  The date in such cases would be most accurately represented by decimal portions of the year (i.e. Eon 19, Genesis 57, Age 4, Century 10, Year 64.525).

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