One idea to explain the universe realistically is just to say that existence is whatever is possible. Impossible things are things that either contradict each other or which have no reason to exist. This last clause has to be added to explain why we don't see innumerable possible things happening all the time, and why only things that have a sequence of causes actually occur.
Now the problem, noticed by Aristotle more than two thousand years ago, is where do the causes start. Either there is a first cause or the sequence moves back infinitely, with no first cause. Another more recent hypothesis is of circular causes, in which the last temporal event is simultaneously the first temporal event, with the help of a closed temporal circle.
Perhaps the universe is something like that, self-sustained in the sense that the intelligent entities in the last temporal parts of the universe will be responsible for its beginning. In that sense we (life on earth) are just a very small step in the direction of creating the powerful Gods responsible for all. Stars, planets, rocks, atmosphere, genes, cells or computers, are, of course, like steps in that direction.
The general idea is that, as intelligence evolves, it encompasses more and more of the world around it, gaining more vision but also more power over it. As intelligence evolves over billions of years, it is likely that it will be able to create alternate universes and, ultimately, to have more and more power to change its own universe.
That parts of the universe may have the power to influence its first state (that gives rise to the "big bang") in such a way as to cause a universe that produces them is a kind of weird and highly speculative idea. But it does not seem inconsistent, and it does seem coherent with everything we know so far about the universe. It provides a continuity between causal sequences of events in such a way that no event that has not a cause does not occur and all events have a cause, although the sequence itself is circular and self-sustaining.
We might also add up the spicy bits coming from Feynman's QED. In his theory a light particle may be imagined as traveling from point A to B in all possible ways, but only the shortest way is actualized, and all the others are simply discarded. In the same way we may imagine that this universe allows in principle for any kind of action allowed by the laws of physics, but only the actions that are compatible with a future state of the universe which creates its own beginnings are allowed.
The second law of thermodynamics might be stated as the idea that all physical systems tend to homogeneity, or to reduce their energy differences. Another way to say this is by saying that a warm body near a cooler body cannot get hotter. Of course, that's precisely what a star usually does. But a star does that by converting lighter atoms into heavier atoms, which releases energy, but cannot be used forever as the light atoms will eventually not be enough to keep these processes going.
So, all the stars will have an end and in a universe ruled by solar power this means the end of life as we know it. But it is very likely that stars are associated with just the first part of the evolution of life: the creation of intelligence. As intelligence evolves, intelligent entities will be able to create their own sources of energy, independently from the stars. And so we will be able to see much more "dark matter" in the universe, not in the form of some strange particles, but in the form of intelligent entities which are able to survive with their own light (not dispersed throughout the universe as stars do).