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That supreme original Personality of Godhead, Lord Shri Krishna, expanding His plenary portion as Maha-Vishnu, the first incarnation, creates this manifested cosmos, but He is unborn. The creation, however, takes place in Him, and the material substance and manifestations are all Himself. He maintains them for some time and absorbs them into Himself again."
-- Srimad-Bhagavatam 2.6.39
If you scroll through the thread earlier, I have given quotes showing that there are several universes already besides this one in our Vedic literatures. We believe that God is personally creating, maintaining, and destroying the universes constantly, and thus this cycle is never ending. Just like inhalation and exhalation, God at the same time creates the universal cosmic manifestion, maintains it for some time, and then it goes into dissolution.
This knowledge has been written down 5,000 years ago, but we believe that such knowledge extended further beyond thousands of years. It is eternal knowledge.