In the recorded scientific chronology, Ole Romer was the first scientist, who demonstrated in 1676 that light travels at a finite speed. In 1865, James Clerk Maxwell proposed in his theory of electromagnetism that light is an electromagnetic wave and travels at a constant speed c. Whereas c = 299,792,458 metres per second (3.00 x 108 m/s approximately ) (186,000 miles per second)
You would be astonished to know that Indian Vedic literature has a mention of speed of light which dates back to c.1315 – 1387. Indian Vedic literature consider light to be like wind.
In Vedic literature, there is a medieval text by a Vedic Scholar Sayana (c. 1315 – 1387). In his commentary on Rig Veda, 4th verse of Hymn 1.50 he said:
tatha ca smaryate yojananam sahasre dve dve sate dve ca yojane ekena nimisardhena kramamana
This statement means: Oh Sun (Sunlight) you traverse 2,202 yojanas in half a nimesa.
The same statement occurs in Bhatta Bhaskara’s commentary on the Taittiriya Brahamana, which dates back to 10th century.
In Puranic literature:
A yojana is about 9 miles (As mentioned in Arthasastra).
In Arthasastra, 1 Yojana = 8000 dhanu (Bow)
1 dhanu = 6 Feet
Though, there is an exception in the Yojana unit, Vedic astronomers like Aryabhata, Brhamgupta used smaller yojanas and such exceptional usage was only confined to the astronomers.
Sayana was not an astronomer, he was a Vedic scholar. He was one of the ministers in the court of Emperors Bukka I and his successors of the Vijayanagar Empire. Being a scholar of Vedas and Puranas he would be expected to use the “Standard” Arthasastra units.
The time measurements defined in Puranas are as:
15 nimesa = 1 kastha
30 kastha = 1 kala
30 kala = 1 muhurta
30 muhurta = 1 day and night
Therefore, 1 nimesa = 16/75 seconds
If we calculate speed of light using these units, it comes very close to the correct figure of 186, 000 miles per second.
In 1890 an edition of Rigveda edited by Max Muller – the German Sanskritist, was published which became very famous. Sayana’s statement was printed in this edition and Max Muller claimed to have used several 400 year old manuscripts of Sayana’s commentary.