Until I am measured I am not known,
Yet how you miss me when I have flown.
Can you figure out the answer to this riddle? If you can’t right now, you might be able to by the end of this article. (If you must know at this moment you can also just scroll down to the end and see.)
Today I will be writing about calendars! Particularly, calendar systems. Most people living in the western world might see the Gregorian calendar (which is our January, February, etc. calendar) as the indisputable calendar of all time. The Only Calendar. The calendar to end all calendars. However, many other calendars exist in the world, and they are in use to this very day.
The concept of time seems intrinsic to the way things are. Time is just time and it is an indisputable truth. Yet when we look at minutes, hours, days and so on, we aren’t actually looking at time itself, and instead a measurement. What most people think of as “time” is simply a measurement. Like liters for volume, meters for length, hours, days, months and years are yet another system of measurement. Like every other form of measurement, there are multiple measuring systems; different methods of describing the same thing.
Since history, the passage of time has been measured using the skies as a reference point.
Diurnal cycles, heavenly movements; we use the skies as a reference point for time because it is so predictable. We can rely on the sun to rise every morning, and set every night. The moon’s movements seem more fickle, but there is a very predictable rhythm that emerges over time.
People that live in the western world (Europe, America and it’s colonies etc.) live at the mercy of the sun. The sun dictates everything in our lives. It sets the rhythm of the day, and it determines how we keep track of the passage of time.
Thus, our calendar is sun-based.
This is a solar calendar. The year is set to a cycle of the sun. The sun is responsible for the seasons. The dead of summer is when the sun at it’s highest point in the sky. In many regions, the days are longer and hotter. The sun is at it’s lowest point in the winter. The days are obviously ruled by the sun’s rising and setting cycles.
The solar calendar we use today is called the Gregorian calendar. This calendar was named after Pope Gregory XIII. It has 365 days, and an extra day every four years on what is called the leap year.
Other solar calendars in use today are:
- Assyrian Calendar – used by the Assyrian people and the year begins with spring
- Copic Calendar – used by Coptic Christians. There are only three seasons that are four months long
- Indian National Calendar – used in India alongside the Gregorian
- Solar Hijri Calendar – official calendar of Afghanistan and Iran. The year begins on the vernal equinox
Solar calendars feel intuitive, and many people may believe it is the only calendar in existence, there are are actually more calendar systems out there! One such system is the lunar calendar!
The lunar calendar follows the moon’s monthly cycles.
While the solar calendar is based around the solar year, the lunar calendar is based on the lunar month. One cycle of the moon, is approximately 29.5 days long. Lunar cycles do not match up perfectly with the solar year, so there is a bit of a seasonal drift over time. However, the calendar “resets” in a 33 lunar year cycle.
The Islamic calendar (or the Lunar Hijri calendar) is a lunar calendar in use today.
The start of each month is determined through observation of the moon. When the new crescent moon following the new moon is visible in the sky, the month begins. For this reason, a month can be either 29 or 30 days. Because this calendar is so dependent on the moon and sighting of the moon, new days begin after sunset. In contrast, the new day in the Gregorian calendar begins at midnight.
You are older in the Hijri calendar!
Because the months of the Hjri calendar do not line up with the solar year, a year in Hirji is shorter. Every 33 years, you gain one year compared to the Gregorian calendar. This means every 33 Hijri years, you are one year older in Hijri!
The Islamic calendar is one of the very few true lunar calendars. Many calendars we think of as lunar calendars are actually lunisolar calendars.
Lunisolar calendars are calendars that consider both the sun and the moon.
Many societies lived by the moon. However, they also needed to keep track of the changing of the seasons, a phenomenon that is dictated by the sun. The lunisolar calendar is the perfect medium.
Some lunisolar calendars:
- Chinese Calendar – Lunar New Year is the most important holiday. Every year is represented by an animal sign
- Korean Calendar – derived from the Chinese calendar but dates vary by one day because of the slight difference of the moon phase based on location
- Bengali Calendar – has Hindu, Buddhist and Islamic influences
- Hebrew Calendar – time is largely undefined and proportional to the length of a day, which changes by the seasons
- Hindu Calendar – created through painstaking and accurate astronomical observation
There are many more calendar systems in the world, I’ve only gone over a few. Thank you for staying and reading this! I’ll take this time to remind you of the riddle I proposed in the beginning; Until I am measured I am not known, Yet how you miss me when I have flown.
The answer to this riddle is: Time!