This is a really interesting question. I think the easy answer has already been given:
* Stars require lighter elements (Hydrogen, Helium) in order to generate energy (and hence light) from fusion. There is a finite (but thankfully enormous) amount of these lighter elements in our universe, all (in a "black boxed" sense) of which is gradually heading down the energy slope towards being fused into iron. Eventually this fuel will run out, everything will cool down, and no new visible light will be generated.
Many stars now, no stars future, requires a decline. QED.
But the substance of your question was I think more about objects in the visible universe, ie objects from which we can possibly obtain any information. This one is much harder to answer, I think the real answer is "we cant be sure" the timescales the universe operates on so far exceed the period of our observation that we must hesitate to state anything with certainty.
That said, our best shot at giving any answer is to exrapolate from those limited observations. They are all we have. 781
I am going to choose to proceed on the assumption that "the universe tomorrow will behave exactly the same as the universe today" and "the universe at distance operates the same as in our locality" i.e. that the laws of physics are both space and time invariant.
The facts we know:
* the universe is expanding. Now by this we dont simply mean that the objects in the universe are getting further apart, although they are, we mean that the rate at which they move apart is increasing, and not only is it increasing, it is increasing proportional to an objects distance from the observer. This is analagous to some underlying stretch in the space between objects.
* The rate at which this expansion or stretch is occuring is accelerating.
* Light travels at a finite speed. ~3*10^8m/s in a vacum. This is the fastest speed that any information can travel in the universe.
From these three statements you would conclde that the visible universe must be shrinking. There would be (an unimaginably huge) distance apart two objects could be at which the acceleration due to distance would be ~3*10^8 m/s/s and within the second objects in that part of the universe would be lost to us
A key point here however is that relativaty tells us that no two objects can exceed the speed of light relative to one another.
This means that no matter how hard you push, whatever force comes from this "stretching" cannot possibly force objects out of the visible universe.
From this I conclude that in fact the scope of the visible universe in terms of objects from which we can obtain information, is probably increasing, and it will probably continue to increase for the entire future of the universe. Further I contend that this increase in scope is likely an asymtotic aproach to some maximum value.
Hope this helps. 781