  Information theory provides shortcuts which allow one to deal with complex
systems. The basic idea one uses for this purpose is the maximum entropy
principle developed by Jaynes. However, an extension of this maximum entropy
principle to systems far from thermodynamic equilibrium or even to non-physical
systems is problematic because it requires an adequate choice of constraints.
In this paper we discuss a general concept of natural information equilibrium
which does not require any choice of adequate constraints. It is, therefore,
directly applicable to systems far from thermodynamic equilibrium and to
non-physical systems/processes (e.g. biological processes and economical
processes). We demonstrate the validity and the applicability of the concept by
three well understood physical processes. As an interesting astronomical
application we will show that the concept of natural information equilibrium
allows one to rationalize and to quantify the K-Trumpler effect.
