Open system (systems theory)

An open system is a state of a system, in which a system continuously interacts with its environment. Open systems are those that maintain their state and exhibit the characteristics of openness previously mentioned.

Open systems contrast with closed systems. Systems are rarely ever either open or closed but open to some and closed to other influences. . Basic characteristics of an open system are environment, input, throughput and output. And some control systems with feedback. The definition of a "system" is often arbitrary; a system may be defined as the region of space under study being characterized by a collection of components or elements related in some way.

The concept of an "open system" is originally developed in thermodynamics, and since the 1950s also in systems theory. Nowadays the concept has its applications in the natural and social sciences.

An open system can also relate to studying momentum and how objects react from other objects.

In the natural sciences
In the natural sciences an open system is one whose border is permeable to both energy and mass. In physics a closed system, by contrast, is permeable to energy but not to matter.

Open systems have a number of consequences. A closed system contains limited energy. The definition of an open system assumes that there are supplies of energy that cannot be depleted; in practice, this energy is supplied from some source in the surrounding environment, which can be treated as infinite for the purposes of study. One type of open system is the so-called radiant energy system, which receives its energy from solar radiation – an energy source that can be regarded as inexhaustible for all practical purposes.

In the social sciences
In the social sciences an open systems is a process that exhange material, energy, people, capital and information with its environment.