What is the fate of our existing universe? Will it destroy? To explain it scientifically first look at the origin of universe. Big Bang is considered as the origin of our universe. Big Bang is nothing but an expansion. This expansion had started from a point. According to Big Bang theorem every substance of the universe are expanding from hot and dense state toward cold and competitively less dense state. Day by day the distance of every mater from the originating centre is increasing. Simply to say that with a continuous expansion of universe, it is getting bigger in size.
Now let consider there may be a large number of universe that we do not know now. If our universe continuously expands and get bigger in size, it is possible to do same behaviour of another universe that is nearby our own universe. If it is true then once a time may come that the horizon or our universe will get closer to other universe. If expansion is continuing a friction will happen. Another things also may happen. That is expansion is stop and get back of universe.
Another things may explain. Everything of our universe is forwarding from the centre point. But in 1927, George Lemaitre states thatexpandinguniverse might return back to the singular point. That means all of the things of the universe will concentrated into a point.
Before discovery of dark energy, most of the cosmologists thought that universe will remain expanding until the critical density of the universe reach into the mass density. That was indicates that the expansion of universe have a finite boundary. When the universe will reach in a maximum size, then it will turn to return back. That is called Big Crunch. The accumulation of the substance of universe into a single point is termed as collapsing.
In collapsing period, most of the scientists believes to happen following incident.
1. Star formation will ceased. Because in each galaxy interstellar gas would consumed.
2. The average temperature will be absolute zero.
3. Proton will unstable and baryonic matter will undetectable or disappeared.
4. When total mass and energy of the universe will collapse into a single point black hole will create.
