The termansible refers to a category of fictional technological devices capable ofsuperluminal or faster-than-light (FTL) communication. These devices can instantaneously transmit and receive communicative and informational data streams across vast distances and obstacles, including between star systems and even across galaxies. As a name for such a device, the termansible first appeared in a 1966 novel byUrsula K. Le Guin. Since that time, the broad use of the term has continued in the works of numerous science-fiction authors, across a variety of settings and continuities.^[1] Related terms areultraphone andultrawave.^[2][3]

Ursula K. Le Guin first used the wordansible in her 1966 novelRocannon's World.^[1][4] Etymologically, the word was a contraction ofanswerable, reflecting the device's ability to deliver responses to their messages in a reasonable amount of time, even overinterstellar distances.^[5]

The ansible was the basis for creating a specific kind of interstellar civilization, where communication between far-flung stars is instantaneous, but humans can only travel atrelativistic speeds. Under these conditions, a full-fledgedgalactic empire is not possible, but there is a looser interstellar organization, in which several of Le Guin's protagonists are involved.^[6]

Although Le Guin invented the nameansible for this type of device (further developing its details in her fictional works), the broader concept of instantaneoussuperluminal or FTL communication had already existed in science fiction. Similar communication functions were included in a device called an "interocitor" in the 1952 novelThis Island Earth byRaymond F. Jones, and the1955 film based on the novel. Similarly in 1954, another of these devices called the "Dirac Communicator" appeared inJames Blish's short storyBeep, which was expanded into the 1974 novelThe Quincunx of Time.^[7] Additionally,Robert A. Heinlein, in his 1958 novelTime 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 ofsimultaneity.^{[citation needed]}

In her subsequent works, Le Guin continued to develop the concept of the ansible:

• InThe Left Hand of Darkness (1969), Le Guin writes that the ansible "doesn't involve radio waves, or any form of energy. The principle it works on, the constant ofsimultaneity, is analogous in some ways togravity ... One point has to be fixed, on a planet of certain mass, but the other end is portable."
• InThe Word for World Is Forest (1972), Le Guin explains that in order for communication to work with any pair of ansibles, at least one "must be on a large-mass body, the other can be anywhere in the cosmos".
• InThe Dispossessed (1974), Le Guin tells of the development of the theory leading up to the ansible.^[8]

Any ansible may be used to communicate through any other, by setting its coordinates to those of the receiving ansible.^{[citation needed]} They have a limitedbandwidth, allowing at most a few hundred characters of text to be communicated in any transaction of a dialog session, and are attached to a keyboard and small display to perform text messaging.^{[citation needed]}

Since Le Guin's conception of the ansible, the name of the device has been borrowed by numerous authors. While Le Guin's ansible was said to communicate "instantaneously",^[8] the name has also been adopted for devices capable of communication at finite speeds that are faster than light.

American authorOrson Scott Card in hisEnder's Game novels used the term "ansible" as an unofficial name for the "Philotic Parallax Instantaneous Communicator" device, which transmits information across infinite distances with no time delay.^[9] In the firstEnder's Game novel (1985), Colonel Graff states that "somebody dredged the nameansible out of an old book somewhere".^[9] In an answer on the question-and-answer websiteQuora, Card explained why he chose to appropriate LeGuin's term "ansible" instead of developing a new in-universe name for one:

In a FTL universe, you have several levels. [If you] can travel hyperfast, but no radio signal can outstrip [outrun] your ship, [then] you have to carry the mail with you. It's like the way things were between Europe and America before the laying of the successful transatlantic cable. But once it was laid, messages could be sent long before a ship could make the passage. That is like the ansible universe in Ursula K. LeGuin's earlyHainish novels. Since I needed to use exactly that rule set, why not use the word – an excellent word – which I apply in the same way we all say 'robot,' an invented word that has entered the language, [and thereby] pay tribute to the writer from whose works I learned the word.^[10]

Card's ansible in theEnder's Game universe works via fictional subatomic particles calledphilotes.^[11] The twoquarks inside api meson can be separated by an arbitrary distance, while remaining connected by "philotic rays".^[11] Card's version of the ansible also features in the video gameAdvent Rising, which he helped write the story for.^[12]

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Numerous other writers have included ansibles. Notable examples include:

• Vernor Vinge, in the 1988 short story "The Blabber."^[13]
• Joe M. McDermott, in the 2017 novelThe Fortress at the End of Time.^[14]
• Thomas Happ, in the 2021MetroidvaniaAxiom Verge 2, uses the term for superluminal - and transdimensional - communication terminals.^[15]
• David Wellington, in the 2024 novelRevenant-X.^[16]
• Elizabeth Moon, in the 1995 novelWinning Colors.^[17] and the novelVatta's War
• Jason Jones, in the 1995 computer gameMarathon 2: Durandal.^[18]
• L.A. Graf, in the 1996Star Trek: Deep Space Nine novelTime's Enemy.^[19]
• Neal Asher, in his Polity series of novels includingGridlinked (2001), in which theruncible, named in homage to the ansible,^{[citation needed]} is an interstellar wormhole generator/teleporter.
• Dan Simmons, in the 2003 novelIlium.^[20]

Many authors have depicted FTL communication devices in their fictional works without necessarily using the term "ansible."

• Christopher Rowley, in his 1986 novelStarhammer, describes the Deep Link, an instantaneous interstellar communicator. Most commonly used for messaging, it is capable of voice and video conversations as well, although the latter only at great expense.^[21]
• The New Jedi Order, 1999, featured enemies, the Yuuzhan Vong, use organic communication devices known as villips, which can transmit over infinite distances thanks to telepathic connections formed while being harvested in groups.^{[citation needed]}
• Philip Pullman, in the 2000 novelThe Amber Spyglass, part of theHis Dark Materials trilogy.^[22]
• Liu Cixin, in the 2008 trilogyRemembrance of Earth's Past.^{[citation needed]}
• Kim Stanley Robinson, in the 2012 novel2312.^[23]
• Becky Chambers, in her Wayfarer novels, including the 2014 novelThe Long Way to a Small, Angry Planet, and 2016 novelA Closed and Common Orbit.^{[citation needed]}
• L.J Cohen in the 2014 novelDerelict.^{[citation needed]}
• Neon Yang, in the 2017 novellaWaiting on a Bright Moon.^[24]

Look upansible in Wiktionary, the free dictionary.

• Bloom, Harold, ed. (1986).Ursula K. Le Guin (1st ed.). New York, NY:Chelsea House.ISBN 0-87754-659-2.

• Faster-than-light communication
• Fictional technology

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