BG Chap 8 - Lifespan of Brahmā Brahmaloka and other planets are
destroyed because of limitations of time. Even if Brahmā, the
master of the planet, must die, what can be said of others? The
persons situated on elevated planets such as Mahar-loka know
that one day of Brahmā is a thousand cycles of the four yugas by
human calculations and such is the duration of Brahmā’s night
also. The four yugas are Satya (lasts 1,728,000 years), Tretā
(lasts 1,296,000 years), Dvāpara (864,000 years) and Kali (lasts
432,000 years). The total duration of these four yugas is thus
4,320,000 human years. One thousand of this cycle of four yugas
is one kalpa or one day of Brahmā. Using a different
calculation: One year of human is a day and night of the
devatās. Thus 360 days of the devas (1 year of deva) is 360
human years. Twelve thousand devatā years is 4,320,000 human
years, and this makes a cycle of four yugas. One thousand of
these cycles makes one day of Brahmā. His night is also the same
duration. One hundred of those year