Each
manvantara lasts for 306,720,000 years (852,000 divine years; 1 divine year = 360
solar years) and repeats seventy-one
Yuga Cycles (world ages). In a
kalpa (day of
Brahma), which lasts for 4.32 billion years (12 million divine years or 1,000
Yuga Cycles), there are a total of fourteen
manvantaras (14 x 71 = 994
Yuga Cycles), where each is followed by and the first preceded by a
manvantara-sandhya (fifteen
sandhyas) with each
sandhya lasting for 1,728,000 years (4,800 divine years; the duration of
Satya Yuga). During each
manvantara-sandhya, the earth (
Bhu-loka) is submerged in water. Each
kalpa has 14
manvantaras and 15
manvantara-sandhyas in the following order: • 1st
manvantara-sandhya ( adi sandhya) • 1st
manvantara • 2nd
manvantara-sandhya • 2nd
manvantara • ... • 14th
manvantara-sandhya • 14th
manvantara • 15th
manvantara-sandhya Manusmriti, Ch. 1:
Surya Siddhanta, Ch. 1:
Vishnu Purana, Part 1, Ch. 3: ==Manus==