The Last Catastrophe of the Third Period is determined by the changes in time and order of the cosmos. It is a natural predestination which is beyond the ken of human intellect.
When Heaven and Earth were created, God called on ten Buddhas to the world, seven to rule and three to amass the souls.
Both Tien-Tao and catastrophes were descended at the same time during each period of amassing souls.
The Three Periods can also be proved through the history: the development of civilization from Divine right to monarchic authority, and then to democracy corresponds to each of the three periods.
This is similar to what has been called birth, growth, destruction, and emptiness in Buddhism, and the Final Judgment in Christianity and Islam; which all mean the same thing except each has a different appellation.
When will the Last Catastrophe occur?
According to prophecies in Tien-Tao and other religions, this will happen in the near future with no specific date. However, the most important thing is to arouse oneself and others to Tao, do good deeds, and accumulate merits from now on.