टीका

Commentary

With this verse, Krishna introduces the cosmic time scale of the material universe — a framework so vast that it puts all human ambition and achievement into humbling perspective. Understanding this scale is not merely astronomical curiosity; it is the foundation for understanding why liberation — escape from the cycle entirely — is the only truly worthwhile goal.

A yuga cycle consists of four ages: Satya Yuga (1,728,000 years), Treta Yuga (1,296,000 years), Dvapara Yuga (864,000 years), and Kali Yuga (432,000 years), totaling 4,320,000 years. One thousand such cycles make one day of Brahma — 4,320,000,000 years. And his night is equally long. Brahma’s full lifespan consists of 100 such years, making it an almost incomprehensible span — yet it is still finite, still temporary, still within the material cycle.

This verse establishes why the previous verse’s statement — that even Brahmaloka involves return — is not an exaggeration. Even beings who live for billions of human years are still within time, still subject to eventual dissolution. The material universe, however grand and long-lived, operates within the framework of cyclical time.

The phrase ahim raatravido janaah — “those who truly know day and night” — implies that most people do not know this. They live their entire lives within the tiny bubble of one human lifetime (70-100 years) and make decisions as though that bubble were the whole of reality. Knowing the cosmic time scale is a form of genuine wisdom that puts everything into perspective.

Historical Context

The Vedic calculation of cosmic time is one of the most ancient and sophisticated systems of cosmological thought. These numbers — which appeared to Western scholars as fantastical exaggerations when first encountered — are now recognized as the only ancient civilization to have calculated a universe age that is on the same order of magnitude as modern scientific estimates (the current scientific estimate of the universe’s age is approximately 13.8 billion years). The four-yuga system appears throughout the Puranas, particularly the Vishnu Purana and Srimad Bhagavatam, which elaborate the complete Vedic cosmology in great detail.