The term ansible refers to a category of fictional technological devices capable of superluminal or faster-than-light (FTL) communication.
These devices can instantaneously transmit and receive messages across obstacles and vast distances, including between star systems and even galaxies.
[5] The ansible was the basis for creating a specific kind of interstellar civilization, where communications between far-flung stars are instantaneous, but humans can only travel at relativistic speeds.
Similarly in 1954, another of these devices called the "Dirac Communicator" appeared in James Blish's short story Beep, which was expanded into the 1974 novel The Quincunx of Time.
[7] Additionally, Robert A. Heinlein, in his 1958 novel Time for the Stars, employed instantaneous telepathic communication between identical twin pairs over interstellar distances, and like Le Guin, provided a technical explanation based on a non-Einsteinian principle of simultaneity.
][citation needed] Orson Scott Card used the term "ansible" as an unofficial name for the Philotic Parallax Instantaneous Communicator in his 1977 novelette, 1985 novel Ender's Game, and its sequels.