Today, most of us use the Gregorian calendar, which is based on the Earth’s orbit around the Sun. This solar calendar helps us plan our activities and track the seasons. But how did our ancestors manage before knowing the solar dating system? What type of calendars were they using? How did they know when to work, when to celebrate, when to harvest?
It is interesting to know that they used the Moon’s phases to track their activities and maintained their calendar as well, which we now call the lunar calendar. The lunar calendar is based on the Moon’s phases. Each month in a lunar calendar starts with a new moon or the first crescent moon after the new moon.
According to the Gregorian calendar, there are about 30 days in a month. In the lunar calendar, however, each month is approximately 29.53 days long, which is called a lunar month (the time it takes for the Moon to complete one cycle of phases). A lunar year, consisting of 12 lunar months, totals about 354 days. This is about 11-12 days shorter than the solar year.
The Metonic Cycle
To reconcile the lunar calendar with the solar year, ancient civilizations noticed that 19 solar years closely matched 235 lunar months. This is known as the Metonic cycle, a clever way to align lunar months with the solar year.
The Moon and the Sun are the most prominent objects in the sky. Early humans noticed that the Sun appeared to return to the same position each day, but it wasn’t easy to pinpoint the exact spot. On the other hand, the Moon’s phases were more noticeable and easier to track. It made sense for them to call it a day when the Sun returned to the same spot and a month when the Moon showed the same shape again.
The oldest known lunar calendar dates back to around 15,000 BC and was discovered in the caves at Lascaux, southwest France. This calendar shows that early humans were already keenly observing the Moon and using it to mark time.
Lunisolar Calendar
A lunisolar calendar is a calendar that uses both the lunar and solar cycles to determine the year and month:
Lunar phases: Determine the months
Solar cycles: Determine the years
To account for the difference between the lunar and solar years, an extra month is sometimes added to the calendar. For example, the Hebrew calendar uses a leap year to adjust for the difference between the lunar year of 354 days and the solar year.
Calendars in Use Today
Around 40 calendars are still in use today, but the main calendars used around the world are the Gregorian, Jewish, Islamic, Hindu, Chinese, Julian, and Persian calendars. The Gregorian calendar is the most widely used calendar around the world today.
Indian Calenders
India uses two calendars the Saka calendar and the Gregorian calendar,Gregorian Calendar Used alongside the Saka calendar in India.
Saka Calendar: The national calendar of India, the Saka calendar is used in government communications, news broadcasts, and in The Gazette of India. The Saka calendar is based on the lunisolar calendar and has 365 days in a year, similar to the Gregorian calendar. The new year begins in the month of Chaitra, which is around March 21 on the Gregorian calendar. The Saka calendar’s year 0 is 78 AD, which marks the ascension of Kanishka the Great to the throne.
