Most cultures imagine the world to be few hundred human generations old. Hardly anyone guessed that the cosmos might be far older, but the ancient Hindus did. -Carl Sagan, the distinguished Cornell University astronomer, astrophysicist and Pulitzer prize-winning author in his award winning TV series Cosmos episode 10 The edge of the forever.

Video excerpt from the 80′s TV series:

He further goes on to say,

The Hindu religion is the only one of the worlds great faiths dedicated to the idea that the cosmos itself undergoes an immense, indeed an infinite number of deaths and rebirths. It is the only religion in which the time scales correspond, no doubt by accident, to those of modern scientific cosmology.

Its cycles run from ordinary our day and night to a day and night of Brahma. 8.64B years long. Longer than the age of the earth or the sun and half the time since big bang and there are much longer timescales still.

I doubt that the Hindu time-scale which corresponds with the modern science is just a coincidence. Carl Sagan hesitated to state it clearly in front of western audience that Hindu time-scale is huge and compatible with the modern scientific theory. But in the early eighties, Sagan met then Indian diplomat Placido P D’Souza and in a conversation explained about the TV series Cosmos….

….. the main reason that we oriented this episode of COSMOS towards India is because of that wonderful aspect of Hindu cosmology which first of all gives a time-scale for the Earth and the universe — a time-scale which is consonant with that of modern scientific cosmology. We know that the Earth is about 4.6 billion years old, and the cosmos, or at least its present incarnation, is something like 10 or 20 billion years old. The Hindu tradition has a day and night of Brahma in this range, somewhere in the region of 8.4 billion years.

As far as I know. It is the only ancient religious tradition on the Earth which talks about the right time-scale. We want to get across the concept of the right time-scale, and to show that it is not unnatural. In the West, people have the sense that what is natural is for the universe to be a few thousand years old, and that billions is indwelling, and no one can understand it. The Hindu concept is very clear. Here is a great world culture which has always talked about billions of years.

Finally, the many billion year time-scale of Hindu cosmology is not the entire history of the universe, but just the day and night of Brahma, and there is the idea of an infinite cycle of births and deaths and an infinite number of universes, each with its own gods.

And this is a very grand idea. Whether it is true or not, is not yet clear. But it makes the pulse quicken, and we thought it was a good way to approach the subject.

Now lets look at the scale of Hindu time measurement.

Reckoning of time for Brahma.

* 1000 Mahayugas = 1 kalpa = 1 day (day only) of Brahma (Two kalpas constitute a day and night of Brahma)(1 kalpa =4.32 billion solar years)
* 30 days of Brahma = 1 month of Brahma (259.2 billion human years)
* 12 months of Brahma = 1 year of Brahma (3.1104 trillion human years)
* 50 years of Brahma = 1 Pararddha
* 2 parardhas = 100 years of Brahma = 1 Para = 1 Mahakalpa (the lifespan of Brahma)(311.04 trillion human years)

One day of Brahma is divided into 10,000 parts called charanas. The charanas are divided as follows:

The Four Yugas
4 charanas (1,728,000 solar years) Satya Yuga
3 charanas(1,296,000 solar years) Treta Yuga
2 charanas(864,000 solar years) Dwapar Yuga
1 charanas(432,000 solar years) Kali Yuga

The cycle repeats itself so altogether there are 1,000 cycles of mahayugas in one day of Brahma.
* One cycle of the above four yugas is one mahayuga (4.32 million solar years)
* as is confirmed by the Gita statement “sahasra-yuga paryantam ahar-yad brahmano viduh”, meaning, a day of brahma is of 1000 mahayugas. Thus a day of Brahma, kalpa, is of duration: 4.32 billion solar years. Two kalpas constitute a day and night of Brahma
* A manvantara consists of 71 mahayugas (306,720,000 solar years). Each Manvantara is ruled by a Manu.
* After each manvantara follows one Sandhi Kala of the same duration as a Krita Yuga (1,728,000 = 4 Charana). (It is said that during a Sandhi Kala, the entire earth is submerged in water.)
* A kalpa consists of a period of 1,728,000 solar years called Adi Sandhi, followed by 14 manvantaras and Sandhi Kalas.
* A day of Brahma equals (14 times 71 mahayugas) + (15 x 4 Charanas) = 994 mahayugas + (60 Charanas) = 994 mahayugas + (6 x 10) Charanas = 994 mahayugas + 6 mahayugas = 1,000 mahayugas

Links:
Hindu units of measurement
More info about Carl_Sagan
Lost discoveries by Dick Teresi