The Surya Siddhanta · Chapter 8 of 8

#The malignant aspects, the world and the instruments

#The malignant aspects (XI)

Chapter XI describes a moment the Surya Siddhanta treats as dangerous: when the Sun and Moon have the same declination (are equally far from the equator) on opposite sides of a solstice.

When the Moon and Sun are upon opposite sides of either solstice, and their minutes of declination are the same, it is vyatipata, the sum of their longitudes being a half-circle (XI.2).

When they are on the same side of a solstice, with equal declination and the sum of their longitudes a whole circle, it is vaidhrita (XI.1). The text describes the moment in mythic terms — the "fire arising from the wrathfulness of their gaze" (XI.3) — and calls the time "exceedingly terrible ... forbidden for all works" (XI.16–17), though valuable for bathing, giving, prayer and offerings to the ancestors (XI.18). It gives the calculation of the moment and its duration (XI.6–15), and a third vyatipata when the sum of the longitudes falls in the 17th yoga (XI.20).

These are the origin of the names Vyatipata and Vaidhriti among the 27 yogas of the panchanga — the 17th and 27th — which Varahamihira and the muhurta books tell us to avoid for marriages and new undertakings.

The chapter ends with the knots (gandanta): the last quarters of Ashlesha, Jyeshtha and Revati and the first quarters of the following nakshatras are "junctions of the asterisms"; "in all works, one must avoid the terrible trio of vyatipatas, as also the trio of gandantas, and this trio of junctions of asterisms" (XI.21–22).

#Maya's questions (XII.1–9)

Chapter XII returns to the frame story. Maya asks the Sun's emissary:

O blessed one! Of what measure is the Earth? Of what form? How supported? How divided? ... How does the Sun cause the varying distinction of day and night? ... Why does the day of the Fathers consist of a month, but that of mortals of sixty nadis? ... The orbits of the planets and stars — what are their heights? What their intervals? (XII.2–7)

#The answer: the shape of the world (XII.10–44)

• Creation (XII.10–28): the development of the elements and of the creation from the supreme being.
• The egg of Brahma (XII.29): the universe is a hollow sphere, "like a receptacle made of a pair of caldrons".
• The order of the orbits (XII.30–31): the sphere of the stars; below it Saturn, Jupiter, Mars, the Sun, Venus, Mercury and the Moon; below them the realms of the Perfected, the Vidyadharas, and the clouds.
• The Earth (XII.32): "Quite in the middle of the egg, the earth-globe stands in the ether, bearing the supreme might of Brahma, which is of the nature of self-supporting force." The Earth needs no support: it rests in space by its own nature.
• Meru passes through the Earth from pole to pole; the gods live at its northern end, the demons at its southern (XII.34–35); an ocean girdles the Earth (XII.36).
• The four cities a quarter of the Earth apart on the equator: Yamakoti, Lanka, Romaka and the City of the Perfected (XII.37–41) — the same reference points as Aryabhata's.
• The pole stars (XII.43–44): two, at the poles; on the equator both lie on the horizon.

#No top and no bottom (XII.53–54)

And everywhere upon the globe of the earth, men think their own place to be uppermost: but since it is a globe in the ether, where should there be an upper, or where an under side of it? Owing to the littleness of their own bodies, men, looking in every direction from the position they occupy, behold this earth, although it is globular, as having the form of a wheel (XII.53–54).

A clear statement that the Earth is a globe with no absolute "up", and that it only looks flat because we are small.

#Day and night in every latitude (XII.45–72)

The Sun is visible to the gods at the north pole while it moves through the six signs from Aries, and to the demons at the south pole through the six signs from Libra (XII.45–50). At the equator, day and night are always thirty nadis each (XII.56); elsewhere, the day is longer in summer and shorter in winter, increasingly with latitude (XII.57–72) — down to the polar regions, where the Sun does not set for months.

#The dimensions of the universe (XII.73–90)

The stars revolve, "impelled by the provector winds", carrying the planets' orbits (XII.73). The text gives the orbits in yojanas: the Moon's 324,000; the Sun's (with Mercury's and Venus's mean orbits) 4,331,500; Mars's 8,146,909; Saturn's 127,668,255; the stars' 259,890,012; and the whole "egg of Brahma" 18,712,080,864,000,000 (XII.80–90). These follow from the rule that all planets travel the same distance each day (chapter 3), not from measurement.

#The instruments (XIII)

The armillary sphere: how to build and equip a model of the heavens, with its circles and the positions of the stars and planets on it (XIII.1–16). It can be turned by mercury or water to keep pace with the sky — "this is a mystery; if plainly described, it would be generally intelligible in the world", so it is to be learned from a teacher (XIII.17–19).

Other instruments for time (XIII.20–24): the gnomon, staff, arc, wheel, shadow instruments, and water, sand and mercury devices. The classic water clock:

A copper vessel, with a hole in the bottom, set in a basin of pure water, sinks sixty times in a day and night, and is an accurate hemispherical instrument (XIII.23).

The bowl sinks once every nadi (24 minutes). The chapter ends: "He who thoroughly knows the system of the planets and asterisms, and the sphere, attains the world of the planets in the succession of births" (XIII.25).

#Summary

• Equal declinations of Sun and Moon make Vyatipata and Vaidhriti, to be avoided for undertakings — the origin of the two inauspicious yogas; avoid also the gandantas and junctions of nakshatras (XI).
• The universe is a sphere; the Earth is a globe resting in space by its own force, with Meru through its poles and four cities on its equator (XII.29–44).
• On a globe there is no up or down; it looks flat because we are small (XII.53–54).
• Day and night vary with latitude, to months-long days at the poles (XII.45–72); the orbits' sizes follow from equal daily distances (XII.73–90).
• The armillary sphere turned by mercury or water, and the sinking-bowl water clock (XIII).

#Exercises

1. What is Vyatipata, and which panchanga yoga is named after it?
2. Which "trios" does XI.22 tell us to avoid?
3. How does the Surya Siddhanta say the Earth is supported?
4. Explain XII.53–54 in your own words.
5. How does the copper-bowl water clock measure time?

Answers: 1. The moment when the Sun and Moon have equal declinations on opposite sides of a solstice; the 17th yoga, Vyatipata (the 27th is Vaidhriti). 2. The vyatipatas, the gandantas and the junctions of the nakshatras. 3. By its own self-supporting force in the middle of space (XII.32). 4. On a globe every place seems to be "on top"; there is no absolute up or down, and the Earth only looks flat because we are small. 5. It sinks once every nadi (24 minutes), sixty times a day (XIII.23).