Viṣṇu Purāṇa | Book 1 - Chapter 3
Measure of time. Moments or Kāṣṭhās, etc.; day and night; fortnight, month, year, divine year: Yugas, or ages: Mahāyuga, or great age: day of Brahmā: periods of the Manus: a Manvantara: night of Brahmā, and destruction of the world: a year of Brahmā: his life: a Kalpa: a Parārdha: the past, or Pādma Kalpa: the present, or Vārāha.
MAITREYA: How creative agency can be attributed to that Brahma, who is without qualities, illimitable, pure, and free from imperfection?
The essential properties of existent things are objects of observation, of which no foreknowledge is attainable; and creation, and hundreds of properties, belong to Brahma, as inseparable parts of his essence, as heat, oh chief of sages, is inherent in fire.
Hear then how the deity Nārāyaṇa, in the person of Brahmā, the great parent of the world, created all existent things.
Brahmā is said to be born: a familiar phrase, to signify his manifestation; and, as the peculiar measure of his presence, a hundred of his years is said to constitute his life: that period is also called Param, and the half of it, Parārdha.
I have already declared to you, oh sinless Brahman, that Time is a form of Viṣṇu: hear now how it is applied to measure the duration of Brahmā, and of all other sentient beings, as well as of those which are unconscious, as the mountains, oceans, and the like.
Oh best of sages, fifteen twinklings of the eye make a Kāṣṭhā; thirty Kāṣṭhās, one Kalā; and thirty Kalās, one Muhūrta.
Thirty Mūhurtas constitute a day and night of mortals: thirty such days make a month, divided into two half-months: six months form an Ayana (the period of the sun's progress north or south of the ecliptic): and two Ayaṇas compose a year.
The southern Ayana is a night, and the northern a day of the gods.
Twelve thousand divine years, each composed of (three hundred and sixty) such days, constitute the period of the four Yugas, or ages.
They are thus distributed: the Krita age has four thousand divine years; the Tretā three thousand; the Dvāpara two thousand; and the Kāli age one thousand: so those acquainted with antiquity have declared.
The period that precedes a Yuga is called a Sandhyā, and it is of as many hundred years as there are thousands in the Yuga: and the period that follows a Yuga, termed the Sandhyāmśa, is of similar duration.
The interval between the Sandhyā and the Sandhyāmśa is the Yuga, denominated Krita, Tretā, etc. The Krita, Tretā, Dvāpara, and Kali, constitute a great age, or aggregate of four ages: a thousand such aggregates are a day of Brahmā, and fourteen Manus reign within that term. Hear the division of time which they measure.
Seven Ṛṣis, certain (secondary) divinities, Indra, Manu, and the kings his sons, are created and perish at one period; and the interval, called a Manvantara, is equal to seventy-one times the number of years contained in the four Yugas, with some additional years: this is the duration of the Manu, the (attendant) divinities, and the rest, which is equal to 852.000 divine years, or to 306.720.000 years of mortals, independent of the additional period.
Fourteen times this period constitutes a Brāhma day, that is, a day of Brahmā; the term (Brāhma) being the derivative form. At the end of this day dissolution of the universe occurs, when all the three worlds, earth, and the regions of space, are consumed with fire.
The dwellers of Mahaloka (the region inhabited by the saints who survive the world), distressed by the heat, repair then to Janaloka (the region of holy men after their decease).
When the three worlds are but one mighty ocean, Brahmā, who is one with Nārāyaṇa, satiate with the demolition of the universe, sleeps upon his serpent-bed--contemplated, the lotus born, by the ascetic inhabitants of the Janaloka--for a night of equal duration with his day; at the close of which he creates anew.
Of such days and nights is a year of Brahmā composed; and a hundred such years constitute his whole life.
One Parārdha, or half his existence, has expired, terminating with the Mahā Kalpa called Pādma. The Kalpa (or day of Brahmā) termed Vārāha is the first of the second period of Brahmā's existence.