The answer to that question goes back to the basic premise of how our universe operates:
Everything operates in a circle.
What goes around, comes around.
Which means that whatever they saw . . .
-- Could the Mayans have discerned the nature of our 12/21/2012 cataclysm?
They could have conceivably witnessed a passing asteroid, whose approach we’re ignorant of, and surmised it would return and visit its violence on the earth on . . . 12/21/2012.
-- How would the Maya have viewed such a celestial visitor?
They say all celestial objects as gods, none of whom were benign in their attitudes toward humankind. Quetzalcoatl was viewed as the friendliest, but he was defeated and displaced in the heavens by a black god of the death and the everlasting night,Tezcatlipoca. The Maya believed that when the 2012 Long-Count Calendar ran out, Tezcatlipoca would smash the heavenly gates, that he and his infernal legions would scorch the Underworld Road which leads via the constellation, Sagittarius, and scourge the earth—and their final scorching scourge would be our Last Day, the One World’s Last Day . . . 12/21/2012.