Action at a distance (physics)



In physics, action at a distance is the interaction of two objects which are separated in space with no known mediator of the interaction. This term was used most often with early theories of gravity and electromagnetism to describe how an object could "know" the mass (in the case of gravity) or charge (in electromagnetism) of another distant object.

http://en.wikipedia.org/wiki/Action_at_a_distance_(physics)

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Action at a distance (computer science)

Action at a distance is an anti-pattern (a recognized common error) in which behavior in one part of a program varies wildly based on difficult or impossible to identify operations in another part of the program. The way to avoid the problems associated with action at a distance are a proper design which avoids global variables and alters data in a controlled and local manner.

The term is based on the physics concept of the same name, where particles may be created that cancel each other out. Such particles instantaneously communicate information across space regardless of distance in what Albert Einstein called "spooky action at a distance".

http://en.wikipedia.org/wiki/Action_at_a_distance_(computer_science)

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