ihave pasted some excerpts from my book the origns
THE MAHĀYUGAS ARE MENTIONED IN THE MAHĀBHĀRATA
The notion of the Mahāyugas is expressed in the MBH in 2 separate places, the Vanaparva , chapter 18 and in the Harivamsa, and does not occur explicitly in the Saṃhitā epoch of the Veda. BG Siddhārth, the internationally known Astrophysicist and Director of the Birla planetorium in Hyderabad, feels that it appears in an encoded form in RV 10.11.117.
It also occurs in the Ṡatapatha Brāhmaṇa , , the Bhāgavata Purāṇa, and the Markandeya Purāṇa. If we indulge in the hubris that only the Indians resorted to such large timescales we would be grievously wrong. Almost all the ancients exhibited this propensity, for what appeared to be valid reasons
The Harivamsa is an appendix to the MBH. However the number of years are different. In the Vanaparva, the division of the yugas is the usual one and the day of Brahma is also stated to be of 1000 yugas as in the Sūrya Siddhānta. But the number of years in the yugas is different from the one mentioned in the Sūrya Siddhānta.The number of years mentioned in each yuga.
THE POSTULATION OF THE DIVYABDA OR A DIVINE YEAR
If we treat these as divine years we get the same number of years as the Sūrya Siddhānta. However, there is no mention of divine years in the Vanaparva citation. It clearly mentions that the total length of years is much smaller than in the SūryaSiddhānta.
The beginning of the Kritayuga Is stated to take place when the Sun. Moon and Jupiter come in conjunction with the Puṣya asterism. This theory Is certainly different from that of the Sūrya Siddhānta. In the above theory, only the three planets are stated to be in conjunction. The measure of this Yuga will naturally be of smaller size. In the Sūrya Siddhānta the conjunction of all the seven planets in the Ashvini Nakṣatra marks the beginning of the yuga. Its measure will. therefore. be of much larger size. It is. therefore. evident that the theory of the Sūrya Siddhānta is a later development. The improvement in the old theory has been made only by making a slight addition. The concept of the divine years has been introduced in the system so that the period of each yuga becomes very large without tampering with the old system of division. To correspond with the new improvement, the conjunction of all the planets was made the basis of marking the beginning of the epoch. The division of the period of Brahma (1000 yugas) in the Manvantaras is also not met with in the above theory of the MBH which also seems to be of later origin.
In the Harivamsa Purāṇa, on the other hand, the yuga theory is exactly the same as given in the Sūrya Siddhānta. The divine year is defined first as of 360.0 years . Then the verses of the MBH as given in the Vanaparva mentioned above are reproduced ,verbatim and one line is added stating that the above number of years tn a yuga (i.e. 12000) should be regarded as Dvine years Further. as in the Sūrya Siddhānta 71 Chaturyugas are stated to constitute a Manvantara and 14 Manvantaras are stated to constitute a Kalpa.48 Here we have a potential solution to 2 riddles ,
1.the riddle of the excessively large Chaturyugās which appear to be a later amplification, which in reality caused much misunderstanding and
2. the riddle of the date of the Sūrya Siddhānta.
This is one possible solution to the riddle of the Mahā Yugas. We admit we know of no valid reason to assign such large numbers to the Chaturyugas, but then this raises the spectre of how so many of the ancients could be wrong in enunciating the Divine year and assigning these large numbers.
I found this explanation in the book by Sudhi Kant Bhardwaj on the Sūrya Siddhānta
“The appearance of two distinct theories In the MBH and its appendix has brought us very near the solution of the riddle of the time of the Sūrya Siddhānta which has been puzzling the scholars throughout the ages. We can now definitely conclude that the Sūrya Siddhānta was written sometime between the period of the composition of the earliest part of the MBH and the period of the composition of its appendix. known as the Harivamsa Purāṇa
TABLE 3 COSMOLOGICAL TIME AS DEFINED BY THE ANCIENT INDIC
AN ALTERNATE RATIONALE
1 Brahma Lifetime = 100 Brahma Years = 3.1104 *1014 sidereal years
1 Brahma Year= 360 *8,640,000,000 = 3,110.4 *109 sidereal years
1 Brahma Day (day and night) = 2 Kalpa or 2 Aeons = 8,640,000,000. Sidereal years
1 Kalpa = 4,320,000,000 earthly years (Y) =14 Manus + 1Kritayuga = 1000 MY =14*71.4+.4 MahāYugas
We introduce the new definitions, which were in fact mentioned in the MBH VanaParva
Kaliyuga = = 1200 years (Y new) = 1 Yuga
1 MY = 10 KY
Dvāpara = = 2KY = 2400 Ynew
TretaYuga = 3KY = 3600 Ynew
Kritayuga =4 KY = 4800 Y new= 0.4 MY
1Manvantra (M) = 71 MY = 71*12000 Ynew = 852,000 Ynew (Age of Homo erectus)
Delay in creation = 47,400 divyabdas = 47400 (subtract this from the total as the time taken to furnish the apartment)
We will recapture the 360 factor to stay consistent with the cosmological time frames. This is consistent with the Harivamsa definition of a Brahma day.
1 Manu =( 1M +1 KritaYuga)* 360= (856,800 Ynew) * 360 = 308,448,000 Ynew
1 Kalpa = 14 Manus + 1KritaYuga *360= 1000 MY = 12,000,000 DY = 4.32 billion*Ynew
Y = Solar or tropical year
DY = 360 Y = divine year = Ynew
KY =12,000 = Kaliyuga
MY = 10 KY = Mahāyuga
a. Though there Is much controversy about the date of the MBH. yet the general consensus (?) is that the earliest part of the MBH was written in script that we use today ( as opposed to being composed) in the 4th century BCE and was complete in its present form, including its appendix before the beginning of the Christian era. This is the last downward limit of the MBH. We can push this limit backward but accepting the average period as mentoned above, we can fix the terminus ante quem date of the Sūrya Siddhānta approximately as 200 BCE. The other details mentioned In the Sūrya Siddhānta also correspond to the same period. The language, In particular resembles that of the epic period. The selection of the Anushtup metre also suggests It to be the product of the same period because the later astronomical works are generally in the Āryā metre.
A non-vedic view of the time span of a yuga is given by Swami Sri Yukteswar Giri, the guru of Paramahansa Yogananda. This is detailed in his book, The Holy Science. According to this view, one complete yuga cycle is equal to one complete "precession of the equinox", a period of approximately 24,000 years. The ascending (Utsarpiṇī ) phase consists of a 1200 year Kali, 2400 year Dvāpara, 3600 year Treta and 4800 year Krita (Satya) yuga. The descending (Avasarpiṇī) phase reverses this order, thus both ascending and descending phases equal 24,000 years. According to calculations given in the book, the most recent yuga change was in 1699, when the Earth passed from the Dvāpara Yuga to Treta Yuga. We are in an ascending spiral right now, and will pass into the Satya Yuga in 5299 CE. According to the book, the motion of the stars moving across the sky (a.k.a.precession) is the observable part of the Sun's motion around another star. The quality of human intellect depends on the distance of the Sun and Earth from a certain point in space known as the Grand Center, Magnetic Center or Vishṇunābhi. The closer the Sun is to it, the more subtle energy the Solar System receives, and the greater is the level of human spiritual and overall development. As the Sun moves around its companion star, it brings us closer to or drives us farther away from Vishṇunābi, resulting in the rising and falling ages here on Earth.
Yukteswar tells us that the calendars of the higher ages were based on the Yugas, with each era named after its Yuga. Hence, the year 3000 BCE was known as descending Dvāpara 102 (because the last descending Dvāpara yuga began 102 years earlier in 3101 BCE). He stated that this method was used up until the recent Dark Ages, when knowledge of the connection with the yugas and the precession cycle was lost; "The mistake crept into the almanacs for the first time during the reign of Raja Parikshit, just after the completion of the last descending Dvāpara Yuga. At that time Mahāraja Yudhisthira, noticing the appearance of the dark Kali Yuga, made over his throne to his grandson, the said Raja Parikshit. Mahāraja Yudhisthira, together with all the wise men of his court, retired to the Himalaya Mountains... thus there was no one who could understand the principle of correctly calculating the ages of the several Yugas". Thus, Yukteswar assumed that Raja Parikshit was not trained in any vedic principles even though he alone ruled the world many year. Thus, he interpreted that Yugas are not calculated correctly. Consequently, he gave the theory that when the Dvāpara was over and the Kali era began no one knew enough to restart the calendar count. They knew they were in a Kali Yuga (which is why the old Hindu calendar now begins with K.Y.) but the beginning of this calendar (which in 2011 stands at 5112) can still be traced to 3101 BCE, (3101+2011=5112) the start of the last descending Dvāpara Yuga. To this day there is still much confusion why the Kali era starts at this date or what the correct length of the Yugas should be. Yukteswar suggests that a return to basing the Yuga calendar on the motion of the equinox would be a positive step.”
InferrIng from the occurrence of the word Rākṣasālaya. we have suggested above that the Sūrya Slddhanta was written after the Rāmāyaṇa. Some scholars put the date of the likhita or scriptural version of the Rāmāyaṇa as 100 BCE In this perspective. to fix the date of the Sūrya Siddhānta as 200 BCE poses some difficulty. But 100 BCE is the terminus ante quem of Rāmāyaṇa beyond which it cannot be carried downward. The upper limit should be much earlier. The MBH contains the Rāmopākhyāna. the narration of which exactly agrees with that of the Rāmāyaṇa story. We therefore strongly believe that the genuine part of the Rāmāyaṇa must have been composed orally in metre prior to the MBH.”
TABLE 4 A DAY IN BRAHMA’S LIFE OF 1 KALPA
1 Kalpa = 4,320,000,000 earthly years (Y) =14 Manus + 1Kritayuga = 1000 MY =14*71.4+.4 Mahāyugas
Kaliyuga = 432,000 Y = 1KY = 1200 divine years (DY) = 1 Yuga
1 DY = 360 Y
Dvāpara = 864,000 Y = 2KY = 2400 DY
TretaYuga = 1,296,000 Y = 3KY = 3600 DY
Kritayuga = 1,728,000 Y =4 KY = 4800 DY = 0.4 MY =.4/71.4 = 5.6022408964e-3
Mahāyuga (MY) = 4,320,000 earthly years = 10 KY = 12000 DY aka Chaturyuga
1Manvantra (M) = 71 MY = 306.72 million years
Delay in creation = 47,400 divyabdas = 47400*360 = 1,706,4000 civil years (subtract this from the total as the time taken to furnish the apartment)
1 Manu = 1M + 1 Krita or Satya Yuga = 308.448 million years = 856,800 DY
1 Kalpa = 14 Manus + 1KritaYuga = 14*71.4 +.4 = 1000 MY = 12,000,000 DY = 4.32 billion
Y = Solar or tropical year
DY = 360 Y = divine year
KY = 432,000 = Kaliyuga
MY = 10 KY = Mahāyuga
WHAT WERE THE BASIC FEATURES OF THE VEDIC CALENDAR (4000 BCE) – INFLUENCED BY MONSOON
The Vedic Calendar was a lunisolar calendar . It comprised of 3 types of years; Solar Year - a year of 360 civil days (12 māsa with 30 days each), civil year and a Lunar year. We quote Prof K D Abhyankar who gives a very cogent rationale for the subsequent steps that the Indics took “The year or the Samvatsara is the most important constituent, because it controls the seasonal growth of crops and other vegetation that are so important for human survival. It is, therefore, necessary to determine the length of the year. It was discovered quite early that the seasons are related to the position of the Sun in the sky at noon, which in turn is related to the northward and southward motion of the rising Sun on the eastern horizon. Such observations can be easily made with the help of a stick called a Yupa. Hence the two halves of the year namely the Uttarāyana and the Dakṣiṇāyana, became the two basic divisions of the year very early in history. In India, the beginning of Uttarāyana has used for starting the year from remote antiquity as is from the Vedāṅga Jyotiṣa calendar and Aitareya Brāhmaṇa 18.18 and 18.22, where it is stated that on Viṣuvadina, which occurred in the middle of the year, the Sun reached its maximum altitude, that indicated the beginning of Dakṣiṇāyana. In fact, this was the practice of the ancient civilizations. For example, the Gregorian calendar, which begins the year only ten days after the winter solstice, is a relic of this ancient practice.
TABLE 5 HOW OLD IS THE SOLAR SYSTEM
As of Vaiṡākhā pratipada of 2009 CE, May 1 we are in the second quarter of Brahma day (द्वितिय परार्थ ), called Shweta Varāha Kalpa, seventh Manvantaras named Vaivasvata and entered into the first quarter of the 28th Kaliyuga. Already 5110 years of this 28th KY have passed. so the time elapsed in this Kalpa is 6 Manus =1,850,688,000 Y = [6*(306,420,000+1,728,000)] = 6 Manus (includes 6 Jala pralayas or sandhis, periods between Mānvantāras) And 27 MY = 116,640,000 Y (27 * 4,320,000)=27/71.4M = 0.3781512605 M
Add 1 Jala Pralaya(depending on origin of cycle) = 1,728,000 Y or 1 Krita Yuga
And 28th (Krta+Treta +Dvāpara) = 3,888,000 Y (9*432,000) =0.9 MY =.9/71.4 = 0.012605042M
5110 Y of Kaliyuga = 5110 Y = 5110/4,320,000 MY = 1.1828703704 (10*-3) MY
the current year 2010 CE = 1,850,688,000 + 116,640,00 +1,728,000 + 3,888,000 + 5111 =
1 ,972,949,111 Y or Solar years or 1.972949111 Billion years
= 426+27+(.4*7) + .9 +.001182703704 = 456.701182703704 MahāYugas
Deducting 47,400*360 = 17,064,000, the time spent in creation gives 1,955,885,111
To put this in perspective, if we look at a galaxy 2 billion light years away (a unit of distance) we would be looking at an object in time contemporaneous with the age of ½ a Brahma day or the birthday of our Solar system. It is incredible that the Indic ancients were able to fathom such cosmological time frames merely by the use of Observational Astronomy, using just his naked eye, especially when it is recalled that the Romans had no name for a number greater than a thousand, and the state of Tennessee passed a law saying that the value of PI should be legislated to be 3, as late as the 2nd half of the nineteenth century
KNOWLEDGE OF RATE OF PRECESSION DURING ERA OF RV
Before demonstrating the unmistakable fact of the precession inherent in the cosmological time cycles, it would be of interest to the reader to see how the Western translators of the Sūrya Siddhānta made the choice to take the line of least resistance by assuming that the Indics were ignorant of the distinction between Sidereal and Tropical years and of the effects of the Precession:
To make such a division accurate, the year ought to be tropical, and not the sidereal; but the author of the Sūrya‐Siddhānta has not yet begun to take into account the precession…The earliest Hindu astronomers were ignorant of, or ignored, the periodical motion of the equinoxes…
Again this opinion is in error. If Burgess and Whitney were not so blinded by hubris they might have been able to improve their knowledge by careful study of the Sūrya‐Siddhanta. The precession is clearly derived from the cosmological time cycles as shown below. The Chaturyuga of 4,320,000 years is the unit of reference for determining the rate of precession used in the construction of the Hindu cosmological time cycles.
The Indics of that era postulated a constant rate of precession equal to 50″.4 = 0°.014 = ⁷⁄₅₀₀ degrees of precession per sidereal year. This is the same as one degree of precession in 71³⁄₇ = 71.42857 sidereal years. This compares very favorably with the modern value of precession determined by Al Tusi which is 71.6 years. This correlates to the cosmological time cycles as follows: One manu = 71.4 MY (Mahāyuga = Chaturyuga)
¹⁄₁₄th of an introductory dawn = 0.02857 X Chaturyuga
¹⁄₁₄th kalpa = 71.42857 X Chaturyuga
In the interval of ¹⁄₁₄th kalpa there are:
(71³⁄₇) × 4,320,000 × 0°.014 = 4,320,000 degrees of precession = 12,000 precessional years
From table one we see that a period of one Chaturyuga (or 1 MY) is 4,320,000 years and is equivalent to 12,000 divine years. Is it just a happy coincidence that the Cosmological Time Cycles agree with the precession? Burgess and Whitney would probably think so.
It appears that the same number (71.4 manavantras) and 71 3/7 cannot be a coincidence
Other related values of interest are:
1 precessional year (Great Precessional Cycle) = 25, 714²⁄₇ sidereal years
7 precessional years = 180,000 sidereal years
7 × 18 (126) cycles of the 3rd mean motion of the Sun
7 × 24 (168) precessional years
1 Chaturyuga = 168,000 precessional years
1 kalpa = (4,320,000 ÷ 168) × 0°.014 = 360°
