Hi friends!!
Let me ask you some funny but interesting questions--"What would happen,if the universe stopped expanding and began contracting again?
Would the entropy begin to decrease with time?
Would we see the pieces of broken cups gathering themselves together off the floor and jumping back on the table?
Would we be able to remember 'tomorrow's prices in the stock market?'

For this to happen, my friends time must retrace its path bak. Theoretically, the arrow of time does not reverse.
Let me prove it.

It might seem a bit fnny to think about the collapse of the universe as it won't start contracting for at least another ten thousand million years. So,don't worry about that. But, there's a quicker way to find out what will happen. Letsjump into a black hole for a time being. Imagine the collapse a star to form a black hole. It would be like the later stages of the collapse of the whole universe. Thus,if disorder were to decrease conrtacting phase of the universe,it must also decrease inside a black hole. So,the astronautwho fell into a black hole would be able to find the ball that he hadthrown in the black black hole. But,unfortunately he would not be able to contract with anybody else outside the black hole and show the ball, because he would be rtapped by a very strong gravitational field of black hole.

Physicist, Stepen Hawking believed that disorder would decrease, if the universe recollapses. this was because, the universe had to return to a smooth and ordered state,when it became small again.This situation would exactlybe reverse of expanding phase. People in contracting phase would live theirlives backward. They would die before they were born and would get younger as the universe contracted. This idea is attractive, because it would mean a nice symmetry between the expanding and the contracting phases. This was based on a simple model of universe in which the collapsing phase looked like the time reverse of the expanding phase.

However, another physicist,Don Page pointed out that the no boundary condition did not require thecontracting phase necessarily to be the time reverse of the expanding phase. Also, Raymond Laflamme supported him slightly complicated model of the universe.

So,in fact,the no boundary condition implied that disorder would continue to increase during contraction too. And the entropy would increase. So, it can be concluded that arrow of time does not reverse and never will. And hence,a broken cup will never reform on its own...
--Atul Barapatre

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