An ansible is a hypothetical machine capable of
superluminal communicationand used as a plot devicein science fictionliterature.
The word "ansible" was coined by
Ursula K. Le Guinin her 1966 novel, " Rocannon's World". [cite web|url=http://www.worldwidewords.org/weirdwords/ww-ans1.htm|work=World Wide Words|title=Ansible|last=Quinion|first=Michael] Le Guin states that she derived the name from "answerable," as the device would allow its users to receive answers to their messages in a reasonable amount of time, even over interstellar distances.Fact|date=February 2008 Her award-winning 1974 novel " The Dispossessed"cite book | last = Le Guin | first = Ursula K. | authorlink = Ursula K. Le Guin | title = The Dispossessed | origyear = 1974 | origmonth = June | edition = mass ppb. | year = 2001 | month = August | publisher = Eos/ HarperCollins| location = New York | id = ISBN 0-06-105488-7 | pages = 276 | quote = 'They print Reumere's plans for the ansible.' 'What is the ansible?' 'It's what he's calling an instantaneous communication device.'] tells of the invention of the ansible within her Hainish Cycle.
The name of the device has since been borrowed by authors such as
Orson Scott Card,cite book | last = Card | first = Orson Scott | authorlink = Orson Scott Card | title = Ender's Game| origyear = 1977 | origmonth = August | edition = mass ppb. | year = 1994 | month = July | publisher = Tor Books| location = New York | id = ISBN 0-8125-5070-6 | pages = 249 | quote = What matters is we built the ansible. The official name is "Philotic Parallax Instantaneous Communicator", but somebody dredged the name ansible out of an old book somewhere and it caught on.] Vernor Vinge, [cite book | last = Vinge | first = Vernor | authorlink = Vernor Vinge | title = Threats & Other Promises | date = 1988-11-01 | publisher = Baen | location = Riverdale, NY | id = ISBN 0-671-69790-0 | pages = 254 | chapter = The Blabber| quote = 'It's an ansible.' 'Surely they don't call it that!' 'No. But that's what it is.'] Elizabeth Moon, [cite book | last = Moon | first = Elizabeth | authorlink = Elizabeth Moon | title = Winning Colors | edition = mass ppb. | date = 1995-08-01 | publisher = Baen | location = Riverdale, NY | id = ISBN 0-671-87677-5 | pages = 89 | quote = ...when I was commissioned, we didn't have FTL communications except from planetary platforms. I was on "Boarhound" when they mounted the first shipboard ansible, and at first it was only one-way, from the planet to us.] Jason Jones, [Jones, Jason (with Greg Kirkpatrick) ( 1995-11-24) "", computer game, Chicago, IL: Bungie Software. "A connection [?ansible] was left; awaiting the next quiet [?peace] ; and though destroyed by the threes, it will scream over the void one time."] L.A. Graf, [cite book | last = Graf | first = L.A. [Julia Ecklar] | authorlink = Julia Ecklar | title = Time's Enemy | edition = Star Trek "Deep Space 9"TM : Invasion, 3. mass pbk. | year = 1996 | month = August | publisher = Pocket Books| location = New York | id = ISBN 0-671-54150-1 | pages = 203 | quote = '...The two Dax symbionts can communicate with each other across space, instantaneously, because they're composed of identical quantum particles. I've become a living ansible, Benjamin.'] and Dan Simmons. [cite book | last = Simmons | first = Dan | authorlink = Dan Simmons | title = Ilium | edition = hbk. | date = 2003-07-01 | publisher = Eos/ HarperCollins| location = New York | id = ISBN 0-380-97893-8 | pages = 98 | quote = I can see Nightenhelser madly taking notes on his recorder ansible.] Similarly functioning devices are present in the works of numerous others, such as Frank Herbertcite book | last = Herbert | first = Frank | authorlink = Frank Herbert | title = The Whipping Star | origyear = 1970 | date = 1970-April | publisher = "Worlds of If" magazine] and Philip Pullman, who called it a "lodestone resonator".cite book | last = Pullman | first = Philip | authorlink = Philip Pullman | title = The Amber Spyglass | origyear = 2000 | edition = His Dark Materials, 3. mass pbk. | date = 2001-10-02 | publisher = Del Rey | location = New York | id = ISBN 0-345-41337-7 | pages = 156 | quote = 'Well, in our world there is a way of taking a common lodestone and entangling all its particles, and then splitting it in two so that both parts resonate together.'] The "subspace radio", best known today from Star Trekand named for the series' method of achieving faster-than-light travel, was the most commonly used name for such a faster-than-light (FTL) communicator in the science fiction of the 1930s to the 1950s.Fact|date=February 2007 One ansible-like device which predates Le Guin's usage is the "Dirac communicator" in James Blish's 1954 short story "Beep". Isaac Asimovsolved the same communication problem with the "hyper-wave relay" in The Foundation Series. Stephen R. Donaldson, in his Gap Series, introduces "Symbiotic Crystalline Resonance Transmission", clearly ansible-type technology which is very difficult to produce and limited to text messages.
Le Guin's ansible was said to communicate "instantaneously", but other authors have adopted the name for devices explicitly only capable of finite-speed communication (though still faster than light).
In Le Guin's work
The Word for World Is Forest", 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." In " The Left Hand of Darkness", the ansible "doesn't involve radiowaves, or any form of energy. The principle it works on, the constant of simultaneity, is analogous in some ways to gravity... One point has to be fixed, on a planet of certain mass, but the other end is portable." Le Guin's ansibles are not mated pairs as it is possible for an ansible's coordinates to be set to any known location of a receiving ansible. Moreover, the ansibles Le Guin uses in her stories apparently have a very limited bandwidth which only allows for at most a few hundred characters of text to be communicated in any transaction of a dialog session. Instead of a microphone and speaker, Le Guin's ansibles are attached to a keyboard and small display to perform text messaging.
In Card's work
Orson Scott Card's Ender's Game seriesis a widely read series which uses the ansible as a plot device. ("The official name is Philotic Parallax Instantaneous Communicator," explains Colonel Graff in " Ender's Game", "but somebody dredged the name "ansible" out of an old book somewhere"). His description of ansible functions in " Xenocide" involve a fictional subatomic particle, the philote, and contradicts not only standard physical theory but the results of empirical particle acceleratorexperiments. In the "Enderverse", the two quarks inside a pi meson can be separated by an arbitrary distance while remaining connected by "philotic rays". This is similar in concept to quantum teleportationdue to entanglement, although even that is not capable of faster-than-light communication. Also, in the real world, quark confinementprevents one from separating quarks by more than microscopic distances.
There is no known way to build an ansible. The theory of
special relativitypredicts that any such device would allow communication from the future to the past, which raises problems of causality. For this reason, most physicists believe that they will eventually be proven impossible. Quantum entanglementis often proposed as a mechanism for superluminal communication, but our current understanding of that phenomenon is that it cannot be used for "any" sort of communication—superluminal or otherwise—because of the no cloning theoremin quantum mechanics. See time traveland faster-than-lightfor more discussion of these issues.
No cloning theorem
* [http://www.jessesword.com/sf/view/16 Ansible] from the
Oxford English Dictionary[http://www.jessesword.com/sf/home Science Fiction Citations project]
* [http://www.technovelgy.com/ct/content.asp?Bnum=342 Ansible] at Technovelgy
* [http://news.ansible.co.uk "Ansible" Home Page] (fanzine)
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