Question: what are the three yugas?
Answer: chronology of the universe …in the three others, the Tretā, Dvāpara, and Kali yugas. The respective durations of these four yugas were 1,728,000, 1,296,000, 864,000, and 432,000 years. According to the astronomer Aryabhata, however, the duration of each of the four yugas was the same—i.e., 1,080,000 years.