Composed in Vedic Sanskrit, Rigveda is dated and composed roughly to about 1500 -500 BCE. Rigveda is the oldest Vedic scripture; the core is accepted to date back to the Bronze Age and was passed down verbally and through memorization. The text consists of hymns and verses. Rigveda has 1028 hymns and 10600 verses. It is the world’s longest and oldest composition, containing prayers for Vedic Gods such as Indra (lord of heavens), Varuna (Water), Surya (Sun) and many more.

The first quantitative estimate of the speed of light is seen in Indian Vedic scholar Sayana’s commentary on the Rigveda. Rigveda describes the sun’s journey and the concept of light traveling in beams.

तरणिर्विश्वदर्शतो ज्योतिष्कृदसि सूर्य । विश्वमा भासि रोचनम् ॥  Rigveda 1.50.4

You, Surya, outstrip all in speed; you are visible to all; you are the source of light; you shine throughout the entire firmament. Or

Swift and all beautiful art thou, O Surya (Sun), maker of the light illuminating all the radiant realm.

Sayana (Sayan Acharya, a famous commentator on Vedas in the early 14th century and was a minister in the court of Bukka of the Vijayanagar Empire of Karnataka in South India in the early 14th century), describes that sunlight travels 2,202 yojanas in the time span of a Nimish Ardha (half a Nimisha).

तथा च स्मर्यत योजनानां सहस्रम् द्वे द्वे शते द्वे च योजने । एकेन निमिषार्धेन क्रममाण नमोऽस्तु ते ॥

It is remembered here that the sun (light) traverses 2202 yojanas in half a Nimisha (a blink of an eye).
Half Nimisha is equivalent to 0.1056 seconds

The yojana is a Vedic unit of length, which is equivalent to 9.09 miles.
Nimisha is a Vedic unit of time and is equivalent to 0.2112 seconds.

Later, a Danish astronomer, Ole Roemer, in 1676, measured the speed of light.

As per the Rigveda, the speed of light is 189,547 miles per second.
As per modern science, the speed of light is 186,000 miles per second!

Astonishingly so much correctness in the calculations. It is mind-boggling how the ancient sages and seers of the Vedic period were able to calculate the speed of light, which is almost the same as done by Ole in modern science. In Rigveda they provided:

1. the concept of Light
2. calculated the accurate speed of light and
3. Their unit of time was Nimisha, which was 0.2112 seconds, much smaller than our modern science unit of time.

Vedic knowledge was based on experiential and observational skills, as modern science is based on experimental skills. We should appreciate both. The concept of light, its source, and exact calculation of its speed originated in the Vedic period, thousands of years before our scientists started to think about it. It is also remarkable that our modern science proves it right with experiments.

Let us not go into the superiority debate, celebrate both, and give credit justly as both ultimately lead to the search for the truth.