The Surya Siddhanta · Chapter 2 of 8

#Time and the ages

#Two kinds of time (I.10–11)

Time is the destroyer of the worlds; another Time has for its nature to bring to pass. This latter, according as it is gross or minute, is called by two names, real (murta) and unreal (amurta) (I.10).

"Real" time is the time we can measure, beginning with the breath (prana); "unreal" time is the time too small to perceive, beginning with the truti (I.11).

#The units (I.11–13)

A lunar month has thirty tithis; a solar month is the time the Sun takes to pass through a sign; twelve months make a year (I.12–13).

#Days of the gods and years of the ages (I.14–17)

The day and night of the gods and of the demons are opposed — the gods at the north pole see the Sun for half the year, the demons at the south pole for the other half; one of their days is a human year, and 360 of them a divine year (I.14).

Twelve thousand of these divine years are denominated a Quadruple Age (chaturyuga), of ten thousand times four hundred and thirty-two solar years (I.15).

So the great age (mahayuga) is 4,320,000 years. It is divided into four ages in the ratio 4 : 3 : 2 : 1, each with a dawn and a twilight of one-sixth of its length (I.16–17):

(Compare Aryabhata, whose four quarters are equal.)

#Manus and the day of Brahma (I.18–21)

• 71 great ages make a manvantara, the age of a Manu, followed by a twilight as long as a Krita age (I.18).
• 14 manvantaras, with their twilights and an initial dawn, make a kalpa: exactly 1,000 great ages, 4,320,000,000 years — a day of Brahma, with a night of the same length (I.19–20).
• Brahma lives a hundred such years (I.21).

#How much has passed (I.22–24, 45–51)

Of the present kalpa, six Manus with their twilights have passed, and of the seventh Manu, 27 great ages and the Golden Age of the 28th (I.22–23). Creation itself took 47,400 divine years (I.24). From these the text computes the time elapsed to the end of the last Golden Age — 1,953,720,000 solar years (I.47) — and then gives the rule for the ahargana, the count of days from the beginning, reckoned at midnight on the meridian of Lanka (I.48–51).

These enormous numbers are not history; they are the frame of the calculation. Because every planet is assumed to have been in line at the start of the kalpa, the count of days lets each planet's mean position be computed by a simple ratio (chapter 3).

#The nine measures of time (XIV)

The last chapter returns to time:

The modes of measuring time are nine, namely those of Brahma, of the gods, of the Fathers, of Prajapati, of Jupiter, and solar, civil, lunar and sidereal time (XIV.1).

Of four modes, namely solar, lunar, sidereal and civil time, practical use is made among men; by that of Jupiter is to be determined the year of the cycle of sixty years; of the rest, no use is ever made (XIV.2).

The chapter also explains the solstices and the Sun's northern and southern courses (XIV.9), the seasons of two signs each (XIV.10), and how the lunar months take their names from the nakshatras Krittika and the rest (XIV.16).

#Summary

• "Real" time begins with the breath (4 seconds); units up to the day, month and year (I.10–13).
• A divine year is 360 human years; 12,000 divine years make the great age of 4,320,000 years, divided 4:3:2:1 into the Krita, Treta, Dvapara and Kali ages (I.14–17).
• 71 great ages make a manvantara; 1,000 a kalpa, a day of Brahma (I.18–21).
• The count of days is from midnight at Lanka (I.51).
• Nine measures of time; solar, lunar, civil and sidereal are used in practice, Jupiter's for the sixty-year cycle (XIV.1–2).

#Exercises

1. How long is a prana? A nadi?
2. How many years are in the Kali age? In the great age?
3. How many great ages make a day of Brahma?
4. Which measure of time is used for tithis, marriages and fasts?
5. How does the Surya Siddhanta's division of the great age differ from Aryabhata's?

Answers: 1. About 4 seconds; 24 minutes. 2. 432,000; 4,320,000. 3. 1,000. 4. Lunar time (XIV.13). 5. The Surya Siddhanta divides it 4:3:2:1; Aryabhata into four equal quarters.