PURPORT

Now is the term of Vaivasvata Manu, during which Lord Caitanya appears. First Lord Krsna appears at the close of the Dvapara-yuga of the twenty-eighth divya-yuga, and then Lord Caitanya appears in the Kali-yuga of the same divya-yuga. Lord Krsna and Lord Caitanya appear once in each day of Brahma, or once in fourteen manvantaras, each of seventy-one divya-yugas in duration.

From the beginning of Brahma's day of 4,320,000,000 years, six Manus appear and disappear before Lord Krsna appears. Thus 1,975,320,000 years of the day of Brahma elapse before the appearance of Lord Krsna. This is an astronomical calculation according to solar years.