Equinoxes and Dating Vedas
A. There are 4 special days in a tropical year.
- Winter Solstice : Starting of Uttarayanam
- Spring Equinox: Ugadi
- Summer Solstice: Starting of Dakshinayanam
- Autumn Equinox.
B. There are 27 nakshtras as given below.
|Nakshatra||No. of stars||Alternate name||Dedicated to|
C. The earth takes 365.25 days to cover 360 degrees: one full orbit around the sun.
This is our tropical year. In one day the earth covers 0.9856 degrees nowadays. Since the earth is slowing down, there was a time in our past when the earth took only 360 days for a revolution. (How long ago was that? I don’t know right now).
D. The earth wobbles on its axis.
If we take the stars as our fixed frame of reference, then the year is a small fraction longer than our tropical year. This is called the sidereal year. Every tropical year we are short of the sidereal year by 50.3 seconds. (Or almost a minute).
Roughly every 60 tropical years we are short of the sidereal year by 1 degree. (more exactly every 71.6 years we are short of the sidereal year by a degree). We follow a 60 year cycle, in which each year has a name. Roughly every 60*360 years (21600 years), we are short by 360 degrees and we have come a full cycle. (This would be more exactly every 71.6*360 ie 27776 tropical years)
60 year cycle: 1. Prabhava 2. Vibhava 3. Shukla 4. Pramoda 5. Prajāpati 6. Āngirasa 7. Shrīmukha 8. Bhāva 9. Yuvan 10. Dhātri 11. Īshvara 12. Bahudhānya 13. Pramāthin 14. Vikrama 15. Vrisha 16. Chitrabhānu 17. Svabhānu 18. Tārana 19. Pārthiva 20. Vyaya 21. Sarvajit 22. Sarvadhārin 23. Virodhin 24. Vikrita 25. Khara 26. Nandana 27. Vijaya 28. Jaya 29. Manmatha 30. Durmukha 31. Hemalambin 32. Vilambin 33. Vikārin 34. Shārvari 35. Plava 36. Shubhakrit 37. Shobhana 38. Krodhin 39. Vishvāvasu 40. Parābhava 41. Plavanga 42. Kīlaka 43. Saumya 44. Sādhārana 45. Virodhikrit 46. Paritāpin 47. Pramādin 48. Ānanda 49. Rākshasa 50. Anala 51. Pingala 52. Kālayukti 53. Siddhārthin 54. Raudra 55. Durmati 56. Dundubhi 57. Rudhirodgārin 58. Raktāksha 59. Krodhana 60. Akshaya (22nd year – Sarvdhari. 5109 Kali Yuga)
E. The 4 special tropical year days, occur at different times on each sidereal year. This is the precession of equinoxes.
There are 27*4 = 108 Nakshatra padas. The sun ‘steps’ through each of these padas over the course of the 360 degree (27776 tropical years) cycle. Each Pada is 3 deg and 20 min., that is 200 min. It takes the sun 200*60/50.3 ~ 240 years to step through a pada. or 960 years to step through a nakshatra.
In very rough terms, this means that an equinox or solstice will occur at the immediately previous nakshatram about 1000 years later.
Let us say that, when reckoning began, that the spring equinox was in Krttika Nakshatram. And that it is in Ashwini Nakshatram today. That means the sun has stepped through 2 nakshatrams, which implies roughly 2000 years ago.
Let us say that when the reckoning began, the winter solstice was in Krttika Nakshatram and now it is in Moola Nakshatram, then that means the sun has stepped through 11 nakshatram which is about 11000 years ago.
We know where the equinoxes and solstices are today with respect to the fixed stars. If we know where the equinoxes and solstices were then with respect to the fixed stars, then we have a date.
Based on their interpretations of the Vedas and Scriptures and our customs now and then, various astronomers have given us different dates for the Vedas and the scriptures.
Since the Vedanga Jyotisha starts with Krttka as the first star, we think that one of the important tropical days would have coincided with it. Which is that important date and what does it give us for the antiquity of the Vedas?
A Personal Tentative Thought:
Many Indian scholars accept the traditional date of 5109 years ago as the beginning of Kaliyuga and the death of Sri Krishna. ie 3100 BCE. Based on brahmin lineages, I have argued that Rama was two generations prior to Krishna and the Vedic scholars were at least one generation prior to him. Viswamitra who composed the Gayathri Manthram was a teacher to Sri Rama when he got married to Sita Devi. This would give us about maybe 3500 BCE for the Gayathri Mantram.
If we take it that the winter solstice occured in Revathi Nakshatram in Vedic times and that it slipped back to Moola Nakshatram now, I am looking at a date of roughly 8000 years ago or about 6000 BC. (There are other scholars who give this date.)
If we take it that the winter solstice occured in Dhanistha Nakshatram in Vedic times and that it slipped back to Moola Nakshatram now, I am looking at a date of roughly 4000 years ago or about 2000 BC. There are many people who believe that the Harappan civilization was about 2000 BCE.