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Measure — Jyotiṣa & Gaṇita
before this →Time and Action — Jyotiṣa & Kalpa
The applications of measure are the quiet engine of the whole tradition. The calendar needed astronomy; astronomy needed mathematics; and the mathematics turned out to be among India’s most consequential exports.
From altar to planet
Śulba · Āryabhaṭa · Brahmagupta · Bhāskara
The Śulba-sūtras give altar geometry — squares, circles, the Pythagorean relation, and a strikingly accurate √2. The siddhāntas give planetary astronomy: Āryabhaṭa’s earth rotates and the moon shines by reflected light; Brahmagupta works with zero and negatives; Bhāskara reaches for the derivative.
the chainRite → time → astronomy → mathematics. The decimal place,
the sine table, and the numeral system were by-products of getting the fire lit on the
right night.
ŚULBAthe altar — geometry
JYOTIṢAthe calendar — astronomy
GAṆITAnumerals, zero, trigonometry
SIDDHĀNTAthe planetary model
introduces →gaṇitaśulbaāryabhaṭazerosiddhānta