The Encyclopedia Galactica is a fictional or hypothetical encyclopedia of a future galaxy-spanning civilization, containing all the knowledge accumulated by a society with trillions of people and thousands of years of history.

It was first used by Isaac Asimov in his novel Foundation, where it is central to the first part of the plot. Various people have since used the same idea, both in science and in science fiction. Douglas Adams' The Hitchhiker's Guide to the Galaxy series frequently contrasts the Galactica with the presumably more popular Guide. For example, the introduction to the first book notes:

"In many of the more relaxed civilizations on the Outer Eastern Rim of the Galaxy, the Hitch Hiker's Guide has already supplanted the great Encyclopaedia Galactica as the standard repository of all knowledge and wisdom, for though it has many omissions and contains much that is apocryphal, or at least wildly inaccurate, it scores over the older, more pedestrian work in two important respects.

First, it is slightly cheaper; and second, it has the words Don't Panic inscribed in large friendly letters on its cover."

In Asimov's stories it is later revealed that the encylopedia project itself was not actually the central plan for the foundation, but only an excuse for setting up the project to begin with. Regardless the project was continued, although at a slower pace.

Part XII of Carl Sagan's A Personal Voyage television series is titled Encyclopaedia Galactica. In it, Sagan suggests that such an encyclopedia might be broadcast into space and could possibly be received through radioastronomy (see SETI). He explores the idea of how different civilizations, including our own, might be described in such a work. In his version of the encyclopedia, each civilization has a "probability of survival" rating — for a hypothetical highly technologically advanced civilization utilizing Dyson Spheres, he suggests a probability of survival of 99% per 10⁶ years. For Earth, he speculates that the probability of survival might be viewed by other civilizations as only 40% per 100 years, reflecting the Cold War conditions of the time the documentary was made.

Some Wikipedia editors might like to think significant similarities exist between the hypothetical Encyclopedia Galactica and the Wikipedia projects. While both might be attempts to capture a broad range of human knowledge, the Galactica in all its proposed versions likely shares a great deal more with the more conventional Encyclopædia Britannica, as it is generally presumed that the Galactica would be written by paid professionals rather than amateur hobbyists. Both are authored by legions of dedicated scholars. Because of this correlation, one may occasionally find references to characters or quotes from the Foundation novels in self-referencing Wikipedia articles. This is a sledgehammer form of Wikipedia humor.

Other instances of such encyclopedias in fiction include:

• The Repository of the Ancients, from Stargate SG-1
• Adventures of Superman #617 (2003)
• Star Wars: HoloNet News #45

References

1. H2G2 - BBC - h2g2 - The Hitchhiker's Guide to the Galaxy
2. Galaxy Quest - Wikipedia is a real-life Hitchhiker's Guide: huge, nerdy, and imprecise. By Paul Boutin Posted Tuesday, May 3, 2005, at 2:37 p.m. PT on Slate Magazine. Paul Boutin compares Wikipedia and the Encyclopedia Galactica of Douglas Adams' The Hitchhiker's Guide to the Galaxy.
3. Encyclopaedia Galactica
4. Encyclopedia Galactica - A Guide to Asimov's Foundation Universe

Foundation universe | Fictional encyclopedias | Fictional books

Encyclopaedia Galactica | Enciclopedia Galáctica | Enciclopedia galattica | אנציקלופדיה גלאקטיקה | Encyclopaedia Galactica