4.32 billion years

Brahma is a metaphor for the creative impulse in the cosmos

A Kalpa or 4.32 billion years is one day for Brahma

Manu is the metaphor for the supervisory impulse in nature

Supervisory impulse changes 14 times in a Kalpa

Certain order prevails among created beings during a Manu period

This order can change at the end of a Manu period 


Dominant species can vanish at the end of a Manu period 

12,000 precession cycles fit in a Manu period

Precesssion is the slow drift of seasons over centuries 

Surya Siddhanta Text

An ancient Sanskrit text documents ancient knowledge of precession!

I published a book "Ancient Skies & Astronomy Now" with amazing and accurate facts known to ancient Indian astronomers.