Sāyaṇa (सायण, with honorific Sāyaṇācārya ; died 1387) was an important commentator on the Vedas. He flourished under King Bukka I and his successor Harihara II, in the Vijayanagar Empire of South India. He was the son of Māyaṇa, and the pupil of Vishnu Sarvajna and of Samkarananda. More than a hundred works are attributed to him, among which are commentaries on nearly all parts of the Veda; some were carried out by his pupils, and some were written in conjunction with his brother Mādhava or Vidyāraṇya-svāmin.
Sayana's major work is his Vedartha Prakasha (literally, "the meaning of the Vedas made manifest"), or commentary on the Vedas. His commentary on the Rigveda was edited by Max Müller, 1823-1900. The core portion of the commentary was likely written by Sayana himself, but it also includes contributions of his brother Mādhava, and additions by his students and later authors who wrote under Sayana's name. "Sayana" (or also Sāyaṇamādhava) by convention refers to the collective authorship of the commentary as a whole without separating such layers.
He has also written many lesser manuals called Sudhanidhis treating Prayaschitta (expiation), Yajnatantra (ritual), Purushartha (aims of human endeavour), Subhashita (Collection of moral sayings), Ayurveda (Indian traditional medicine), Sangit Sara (The essence of music), Prayaschitra, Alankara, and Dhatuvrddhi (grammar)
Speed of light
Sayana was aware of the finiteness of the speed of light and approximated its value in the following passage from his commentary on Rig Veda(commenting on RV 1.50.4):
- "tatha cha smaryate yojananam sahastrm dve dve shate dve cha yojane ekena nimishardhena kramaman namöstute."
- "तथा च स्मर्यते योजनानां सहस्त्रं द्वे द्वे शते द्वे च योजने एकेन निमिषार्धेन क्रममाण नमोऽस्तुते॥"
- "[O Sun,] bow to you, who traverses 2,202 yojanas in half a nimesha."
Given that a yojana was equivalent to about 5 km and a nimesha to about 106.7 ms, Sayana's approximation to the speed of light comes to about 330000 km/s, which is only 10% off the actual value of c as determined by modern scientific experiments.
Computer scientist and Indologist historian Subhash Kak describes that the Vayu Purana (ch. 50) has a similar passage, where the "speed of the Sun" is exactly 1/18th of Sayana's value. He points out that although a "rationalist" may dismiss the proximity of Sayana's value to the physical constant as simply coincidence, there is evidence of "scientific foreknowledge" in the ancient Indian vedas.
- Vijayanagara Literature from book History of Andhras, p. 268f.
- Encyclopaedia of Indian Literature: sasay to zorgot from book 'Encyclopaedia of Indian Literature, p. 3885f.
- Subhash Kak, The Speed of Light and Puranic Cosmology, Annals Bhandarkar Oriental Research Institute, vol. 80, pp. 113-123, 1999.
- Max Müller, Rig-Veda Sanskrit-Ausgabe mit Kommentar des Sayana (aus dem 14. Jh. n. Chr.), 6 vols., London 1849-75, 2nd ed. in 4 vols. London 1890 ff.
- Rgveda-Samhitā Srimat-sāyanāchārya virachita-bhāṣya-sametā, Vaidika Samśodhana Mandala, Pune-9 (2nd ed. 1972)