The Speed of Light

The speed of light was determined by Roemer in 1675. Recently it has been pointed out that an ancient Sanskrit text of 14th century contains the value of the speed of light that is identical to the modern value. Sayana (1315-1387 A.D.) was a very famous Vedic scholar. He was the prime minister in the court of Emperor Bukka I and his successors of the Vijayanagara Empire. In his commentary on the following verse in the Rigveda he gives the value for the speed of light.

"O Sun! You see all, create brightness and travel very fast. You brighten the whole sky." Rigveda 1.50.4

Sayana comments: "It is remembered that Sun traverses 2,202 yojanas in half a nimesa."

It is to be noted that Bhatta Bhaskara (probably in 10th century) made the same statement in his commentary on Taittiriya Brahmana. He says this to be an old Puranic tradition.

Yojana is an ancient unit of length. Arthasastra defines it as being equal to 8,000 dhanus, which is equivalent to 9 miles. Nimesa is an ancient unit of time. One nimesa is equal to 16/75 seconds. Thus 2,202 yojanas in half a nimesa is equal to 185,794 miles per second after conversion. This is very close to the value of 186,000 miles per second for the speed of light. Why would Sayana call this the speed of the Sun? The speed of the Sun calculated by Indian astronomers was very small compared to this value. It turns out that Sayana was following the ancient Indian tradition of codifying the knowledge. In this code Sun represents light. The discovery of this code is described in the book “Vedic Physics: Scientific Origin of Hinduism”.

This subject has been discussed in detail in a scholarly article ("The Speed of Light and Puranic Cosmology", Subhash Kak, "Computing Science in Ancient India", editors T. R. N. Rao and Subhash Kak, 1998, pp 80-90). More information about the book is as follows:

Computing Science in Ancient India
Edited by T. R. N. Rao and Subhash Kak
Published by Center for Advanced Computer Studies in 1998
University of Southwestern Louisiana 70504
Library of Congress Catalog Number: 98-86952
ISBN: 0-9666512-0-0

Namaskar
Sir,i have read your article and am so impressed my teacher gave me this information of sayana while i was studying physics in college.but now i got clarity about it. thanks for this article .can you give different units of time used in sanskrit.

very interesting

I wonder how can such developed knowledge/science got distroyed. I wish Indian wealth of knowledge come back to India..
Shirish

Where does it come that : dhanus is 9 miles and one nimesa is equal to 16/75 seconds ?

Hi Dr Roy,

My name is Jazz, I was wondering if we could communicate over email. I have a couple questions for you but also I just recently finished reading your book (i purchased it well over a year ago) .. I had come to some conclusions about the vedas as well.. although after reading your book my ideas have changed ( i originally thought soma to be the sugar molecule ) .. I have some questions.. if possible please email me or msg me on how i may contact you..

thank you

jaz

that entire article is copied from another website. I am in the process of trying to confirm the source. As of yet I hav e no evidence of its validity.

yojana is a yoking or harnessing, that which is yoked or harnessed, a team or vehicle, or a course or path.

yojanA is a stage or the distance traversed in one harnessing or without unyoking.

1 yojana is said to comprise either 4 or 8 krosha (a cry or shout, or the range of the voice in calling); and 1 krosha (or goruta ~ as far as a cow’s lowing may be heard, or a bull’s roar) may represent either 1000 or 2000 daNDa (a rod or staff).

Sound radiates in all directions, so perhaps there is some confusion in regarding a krosha either as the radius of travel in one direction or as the full diameter of travel.

Man is the traditional measure of all things, and 1 danda represents 1 pauruSa (a man’s length) which equals 1 dhanvantara (bow-string) or dhanu (bow).

1 yojana measures either 4,000 or (more likely) 8,000 dhanus.

Assuming that 1 paurusha is 6 ft long, then 1 yojana must represent a distance of about 14.6 km (or about 9 miles, as suggested by Monier-Williams).

A full range of self-consistent units was anciently devised from the proportions of man’s own frame, although their exact conversion into modern units is unclear.

The basic unit is an angula (digit or finger), and 1 danda was perhaps originally divided into 100 digits, but 108 is the traditional value, and Aryabhatta prefers 96.

Assuming a 6 ft danda, Aryabhatta’s angula is exactly ¾ inch (or about 1.9 cm).

It does appear that 1 angula has always measured around 1.8 to 1.9 cm, with 1 danda or dhanu ranging from 1.83 to 2.05 m, so that 1 yojana must extend somewhere between 14.6 and 16.4 km.

nimeSa means shutting the eye or winking, and as a measure of time it is a wink of the eye or a moment.

Kautilya’s Arthashastra (c.320 BC) defines 1 nimesha as 1/360,000th of a day and night ~ i.e. 0.24 seconds.

2,202 yojanas in half a nimesha.

Given that 1 yojana is between 14.6 and 16.4 km, 2,202 yojanas must represent between 32,149 and 36,113 km.

Half a nimesha is 0.12 seconds.

Sayana (c.1315-1387 AD) thus gives the speed of light as between 267,910 and 300,940 km/sec.

The currently accepted value for the speed of light is 299,792 km/sec.

Assuming that the true speed of light was actually known to Sayana, who presented “2,202 yojanas in half a nimesha” as a verity; and accepting Kautilya’s value for nimesha; then a perfect yojana would be exactly 16,337.4636 m and a perfect paurusha or danda exactly 2.0422 m in length. And (assuming 108 digits per danda) then 1 angula = 1.89 cm, 1 dhanurgraha = 7.56 cm, 1 dhanurmushti = 15.13 cm, 1 vitasti = 22.69 cm, and 1 hasta (cubit) = 51.05 cm.