March 18, 2018

Why so many New Years? - Part 1 (De-mystifying Jyotish Siddhanta - Ganita)

Even though 1st January is widely accepted as the new year, each community and culture has its own new year. In fact, the Indian Calendar Reform Committee that was set up in 1952 identified more than 30 well developed Vedic (Hindu) calendars that are in use across different parts of India!!! Today being Ugadi (Gudhi Padwa), it may be an apt day to start this series and share what I have been to learn about Jyotish Siddhanta - a subject that deals with astronomical calculations and measurements.

'What exactly is a new year?'. Time, as we know it, is continuous. We cannot comprehend the start nor the end of it. As Sri Sri says, time is not linear-continuous, it is spherical! Understanding this will need quite some appreciation of theoretical physics/ spirituality and we will discuss it under another post.

New year, or the definition of an year, helps us put markers on this infinite scale of time. As we measure distance from one city to another, an year measures the distance on the time dimension. As the distance can be measured from any point, any origin; the year can also technically have any starting point. And that can be a New Year. In fact, we do have anniversaries and birthdays that do the same.

Definitions of a start and end of year helps us take stock of the progress in our lives, businesses, relationships and plan for the next period of time. It is large enough to encompass different seasons and yet small enough to have 80-100 such cycles in one life time.

Most of our life revolves around the seasons that we experience on earth. So, what better than to define an year as a repetition of seasons. This also translates into one revolution of earth around the sun. Thus, was born a basic form of calendar that was based on seasons. It has 4 anchor points - the 2  equinoxes (equal day and night duration), the longest day and the shortest day. These 4 anchor points define the duration of the year.

One could choose any date as the new year and have any definition of small intervals (months) within that. For some reason, the current Gregorian calendar, with variable month durations, became widely accepted with 1st Jan as the new year. We will talk more about this in the next part.

Life would be simple if the nature was that simple :-) There was one additional complexity that was solved by the Indian calendars. The astronomers found that, in the space, one revolution of earth around the sun is a bit longer than the one defined by these seasonal calendars! What that means is, if we were to mark a point in space on the earth's orbit and call the year as the time taken for earth to come back to the same point on the orbit - it would not match with our duration as measured by the tropical (seasonal) calendars.

Why would that be? It turns out that earth has 3 types of movements - not just rotation and revolution that we have studied in the school. There is a 3rd movement - similar to a spinning top whose 'axis of spin' itself rotates. This movement is now called 'precession of the equinoxes'. The difference created by this movement was added in Indian horoscopes as 'Ayanamsa'. Over an extended period of time, this implies that the equinox on earth will occur at a different point on earth's celestial orbit!

The difference is quite small and the accumulation of this difference is approximately 1 day (1 degree) over 60 years. This makes it hard to notice it in one lifespan. How did the Indian Jyotish experts found this this out, is a mystery. Hence, all the Indian new years, festivals are based on the astronomical positions of the sun and moon - rather the seasonal calendar.

Happy Ugadi (New Year) to all of you - welcoming the Vilambi Samvatsara (Vilambi is the name of this year in the cycle of 60 that repeats itself after that) on the Gregorian day of 18 March 2018. This also coincides with the start of spring season - with 'new'-ness in the air.

The other implication that may shock you, is that if you follow western astrology, that relies on the tropical calendar, then there is a 70% likelihood, that your sun sign is not the one that you think it is :-)

More on that in the next part… hopefully, before the next new year on 14th April! Does this cause change in the earth's average temperature across the year? We will find that out in the coming parts of this series.