Ancients used simple astronomical observations in calculating the Yugas.
The Yugas in Indian Tradition
There are enumerated, four Yugas, or Ages in the Vedic tradition:
Satya-Yug: 1,728,000 — 1st Age
Treta-Yug: 1,296,000 — 2nd Age
Dvarapa-Yug: 864,000 — 3rd Age
Kali-Yug: 432,000 — 4th Age
The common ancient symbol or god was the Sun, and there were varying methods of recording the revolutions of the bodies they knew, of the constellation and degrees of the stars in the sky, as well as of the equatorial cycles. Part of the foundation of the Deity was studied by our forefathers in this theatre of celestial observation, of Space around us.
Whether man was in Bactria, Persia, China, Americas, etc., the dial of the Sun, and the elevation of the pole, did not change. Upon the sacred point of the equator, they traced the cycles to the celestial bodies and heaven. The ancients recorded a history, to their knowledge, of the elements, and the cyclic revolutions of celestial and terrestrial objects in space, within mythology; and transmitted them orally, and through written forms.
They concealed their science in fiction and mythology; because then, by these ways, they could be remembered. These records were hid in clever tales. Stories, that could have been true of clan-heroes, etc., were made to fit in with a telling of the cycles of nature, and of the heavens.
A Method in Calculating the Yuga Durations
The Yugas, e.g., were established upon polar motion, and tropical cycles. They did not rely on technology, as possessing none of the millions of dollars equipment, we posses. They relied on other sophisticated methods, observing the cycles of nature and time, for their numbers. Now, what we will begin to refer to is the study of the Tropics, made by ancient astronomers.
The tropics is the region of the Earth surrounding the Equator. At the beginning of the Kali-Yuga, at 36° latitude, the tropics were said to be 54° from the Equator. In the north horizon of the Sun, the summer tropic occurred simultaneously with it, extending up to 72° of north altitude, and the winter tropic occurred simultaneously with the south horizon, and the polar circle round the south pole, to the 72° below the south horizon.
Between the distance of the poles, it was divided into 9 divisions of 4 degrees each. It is marked, that in under 24,000 years, in our time of the Kali-Yuga, the summer tropic would be 4° nearer to the north pole.
There are then, the 9 divisions to ascend, before the tropics coincide with the north pole; and thus, there are nine times 24,000 years before we reach the mid-point of the Kali Yuga, then nine more times before its end.
This in all 9+9=18 (x24), adds to 432,000 — the duration of the Kali-Yuga.
At the end of the Kali-Yug, the tropics would be 36° from the poles, Without recourse to bewildering the reader with length, this method is followed throughout the series of 432,000,000 tropical years, comprising a Divya-Yuga then onward, as illustrated below.
Therefore, we see, the calculations, were founded on a natural basis of astronomical and geographical observations. It would be seen, how the harmony of the numbers, demonstrates why they regarded them as sacred.
In the Seven Yugas of the Blavatsky Theosophy UK Group, it demonstrates, its calculations, through arithmetical progression, which is one method; and the one demonstrated above, was another one, based on ancient astronomy and geography. This demonstrates again, that these ideas were not borne in the minds of children having epileptic visions, or fancies, but by learned astronomers. These astronomers were considered sages, because although ancient scientists, they were also learned in the ancient practice of Yoga.
- Mackey, Samuel A. The Mythological Astronomy of the Ancients in Three Parts (Second Part, or Key of Urania). 1823 ed. (pages 31-33)
- Blavatsky, Helena. The Secret Doctrine. 1888. Index: Yuga.
- Ifrah, Georges. Histoire Universelle des Chiffres. 1994. On History of Numbers.
- Seven Yugas – Blavatsky UK Group