Srimad Bhagavadgita Sadhaka Sanjivani -Swami Ramsukhdas
Link:—Persons even reaching abode of Brahma return back—in the next verse, Lord Krsna tells the reason for it.
Those who know, that a day of Brahma lasts a thousand four-fold Yugas (Ages) and that his night, lasts a thousand fourfold Yugas, they know the reality, about Brahma's day and night. 17
- A day of the gods lasts men's six months and so does a night. Thus a year of the gods lasts three hundred and sixty years of men. Similarly the duration of the four ages—Satya,Treta, Dvapara and Kali is equal to a divine age of the gods. It means that a divine age of the gods is equal to—Satya age of seventeen lac and twenty-eight thousand years,Treta age of twelve lac and ninety-six thousand years, Dvapara age of eight lac and sixty-four thousand years and Kali age of four lac and thirty-two thousand years—total forty-three lac and twenty thousand years. It is also called 'Mahayuga or'Caturyugi Brahma's one day lasts a thousand divine ages of the gods (men's four thousand, three hundred and twenty million years) and so does his night. This day of Brahma is called 'Kalpa' or 'Sarga' (Creation) and the night is called 'Pralaya' (Dissolution).