This question is raised based on the information I read in this link. I wondered how can we celebrate Lord Kalki anniversary? We do not know whether Sri Kalki (Avtar of Sriman Naaraayan) has already incarnated. OK. People say all worlds and yuga(s) existed even in past, hence, creation and destruction is a continuous process.

If our Astrological science has recorded the commencement of each Avatar then we should be able to declare the exact period of each Avatar without any scope for ambiguity.

Hope learned folks in this subject can throw some light on this.

PS: BTW, I m not promoting that site here. How ever that site provides answers to many of our simple queries in Panchang