Will the change ever end in the universe?

When we think about the equilibrium in the universe, we say that the equilibrium is the situation where energy flow ends.  In the case of the universe, its energy flow is like a lake. Waves on the surface of that lake tell. That there is movement in that water. Same way, there are waves in the energy fields in the universe. 

The energy is like water. It turns destructive only when it moves. In the same way, we can benefit energy only if that energy moves. And we can say that standing energy cannot affect the material. Only moving energy can push or pull particles. 

The energy flow from material to the environment is the thing. That keeps the universe in dynamic change. The energy flow or quantum vaporization is the event. Their material turns into wave movement. And the reason for that is the expansion of the universe. 

Without that energy flow the universe would not expand, and oppositely thinking that energy flow also causes at least part of the universe's expansion. Another thing is that the energy flows out from the universe because the energy level in the universe is higher than its environment. 

The energy flow in the universe is the thing, that keeps things going. And without that energy flow things would freeze immediately. We can say that all material formed in the event, called: the Big Bang. Expansion of the universe began just after the Big Bang. 

The local geometry of the universe is determined by whether the density parameter Ω is greater than, less than, or equal to 1. From top to bottom: a spherical universe with Ω > 1, a hyperbolic universe with Ω < 1, and a flat universe with Ω = 1. These depictions of two-dimensional surfaces are merely easily visualizable analogs to the 3-dimensional structure of (local) space. (Wikipedia, Shape of the universe)

Ω > 1 is the only case in which the Big Crunch can happen. 

Materia is a form of energy. And the material is turning into a wave movement. The wave movement is another form of energy. 

During that expansion distance between particles increases. That causes a situation where the interaction between particles turns weaker. And that thing causes the effect, that natural forces in the universe turn weaker. There are also quantum fields in the universe. Those quantum fields are like gas in the atmosphere. When the universe turns larger, those quantum fields turn weaker, because the same energy must fill the larger entirety. 

And if we compare that thing with gas, we can say that the same gas mass must fill the larger energy, and that means gas pressure turns lower. Same way we can say that energy pressure turns weaker, if we can say that energy has pressure. Or rather saying. The energy level in the universe turns lower. And that will make the universe colder. 

But will the universe never reach energy stability or equilibrium? If the universe is not a ball-shaped structure or sphere it will expand forever. Or we can say that expansion is infinite. That means the universe will never reach the ultimate equilibrium. The interaction in the post-material universe is an extremely weak thing. But if the ultimate fate of the universe is the big silence. Those energy fields that travel away from each other. Meaning that the situation is not completely equilibrium. 

At that moment the material is turned into electromagnetic waves. And those waves continue their travel forever. That is an oversimplified version of the very complicated theorem. There is the possibility that in the very old universe, the detonating black holes send the network of radiation across the great stability. 

Those waves of energy can cross each other, and it's possible. Those cross points will start to pull energy and material remnants to them. That thing is the Big Crunch. The base idea of those models is that there are no other universes. But if those other universes exist. That thing turns even more complicated. 

https://bigthink.com/starts-with-a-bang/universe-reach-equilibrium/

https://en.wikipedia.org/wiki/Shape_of_the_universe

https://en.wikipedia.org/wiki/Ultimate_fate_of_the_universe