The ages
युगyugaAn age, yuga, is first a yoke or a pair, and then a long span of time. The tradition counts four ages in a cycle: the Kṛta or Satya, the Tretā, the Dvāpara and the Kali, each shorter and darker than the one before. Righteousness stands whole in the first and fails by degrees until the last, which the tradition holds to be the present one. Four ages together make a great age, a mahāyuga, and a thousand great ages make a kalpa, a day of Brahmā, at whose end the world is drawn back and afterwards put forth again. The figures in the table are the tradition's own reckoning of time and are not dates of history.
The hymn speaks of the ages in three ways. The names Yugādikṛt and Yugāvarta make the Lord the maker of the beginning of the ages and the turner of their cycle, so that time itself rests in His hand. Bhīṣma's opening answer says that all beings come forth from Him when an age begins and return to Him when it ends. And Brahmā's verse bows to Him who bears a thousand crores of ages, a crore being ten million, so that the number says only that He is beyond counting. The Gītā verse near the end promises that He comes into being age after age to protect the good and set dharma firm.
| Age | Length in human years, as the tradition reckons | Share of a great age |
|---|---|---|
| Kṛta or Satya | 1,728,000 | Four parts |
| Tretā | 1,296,000 | Three parts |
| Dvāpara | 864,000 | Two parts |
| Kali | 432,000 | One part |
| A great age, mahāyuga | 4,320,000 | Ten parts |
| A kalpa, a day of Brahmā | 4,320,000,000 | A thousand great ages |
SourcesMonier-Williams Sanskrit-English Dictionary: yugaMonier-Williams Sanskrit-English Dictionary: kalpa