ansible

Fictional device for instantaneous communication popular in science fiction settings. Preferrable over radio (which is limited by the speed of light) when travelling vast distances in space.

The ansible first appeared in Ursula K. Le Guin's The Left Hand of Darkness, had its origin explained by Le Guin in The Dispossessed, and was later popularized by Orson Scott Card in Ender's Game.

The ansible uses something called the "Constant of Simultaneity" for operation. This required one end of the ansible link to be hosted on a planet, or similar object of non-trivial mass.

This is also the name of the Hugo award winning SF fanzine published by Dave Langford from his top secret facility in Reading, England.

It is a useful source of convention information, change of address (CoA) listings, rumour, scandal, and examples of bad grammar (other people's) for the entire science fiction community.

The ansible is a device in a number of works of science fiction, the first of which was Ursula K. Le Guin's Rocannon's World, and the most famous of which is Orson Scott Card's Ender series. In the Ender series, the official name of the device is the 'Philotic Parallax Instantaneous Communicator', and it is further explained that the term 'ansible' was "dredged out of an old book somewhere," a definite shout-out to LeGuin.

The Card ansible enables faster-than-light transfer of information in a universe where faster-than-light movement of matter and energy is impossible. The way that the ansible works is somewhat analogous to quantum entanglement: two quarks in a pi meson are separated and contained within the ansible. The two quarks, despite being physically separated, remain connected to one another through what Card calls a 'philotic ray'. Transmission of information takes place through manipulating one of the quarks, which reverberates along the philotic ray and affects the other quark instantaneously, no matter the distance.