Did human life exist billions of years ago on this planet?
Who knows? I don’t know!
One thing I can tell you is, the Panchang (Hindu calendar and almanac, which follows traditional units of Indian timekeeping, and presents important dates and their calculations in a tabulated form) that the ancient people have made is so perfect.
In those days, they never had telescopes or all these sophisticated instruments. How did they manage to measure the movement of every star, planets, and the timing? Everything is so perfect. In fact it is perfection to the minute; it is amazing. They calculate and tell you when and what time the eclipse will begin, which minute it is going to end, in which part of the world it will be in another hundred years. That much calculation has been done.
You will be startled to see the perfection of astronomy, and the calculation by which the ancient people made the Panchang.