…The unmanifested forces of time are so powerful that they reduce all matter to oblivion in due course. In Kali-yuga, the last millennium of a round of four millenniums, the power of all material objects deteriorates by the influence of time. In this age the duration of the material body of the people in general is much reduced, and so is the memory.
The great sage Vyāsadeva could see this by his transcendental vision. As an astrologer can see the future fate of a man, or an astronomer can foretell the solar and lunar eclipses, those liberated souls who can see through the scriptures can foretell the future of all mankind. They can see this due to their sharp vision of spiritual attainment. (from purport to SB 1.4.17-18)
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The Hare Krishna Movement 