History Main / SubSpaceAnsible

* In Creator/JohnScalzi's ''Literature/OldMansWar'' trilogy the CDF is only able to communicate between systems using courier drones.

* In ''Film/GuardiansOfTheGalazyVolumeTwo, the Sovereign are are able to manually control a legion of drones from lightyears away from their homeworld.

* The ''Series/MightyMorphinPowerRangers'' communicators, which are connected to the Command Center's [[TeleportersAndTransporters teleportation system]], can communicate across incredible distances.

* In the ''Literature/TowerAndTheHive'' series by Anne [=McCaffrey=], PsychicPowers not only provide interstellar communication, but interstellar ''travel'' by psychokinetic [[TeleportersAndTransporters teleportation]].

* Creator/StephenRDonaldson's ''Literaure/GapCycle'' features an aversion. Much of the story deals with the fact that vital information can't travel FTL unless using an unmanned vessel that goes FTL itself. The Amnion do briefly try to use some sort of experimental "symbiotic crystalline resonance device" as an FTL Radio, which becomes an important PlotPoint.

* Creator/StephenRDonaldson's ''Literaure/TheGapCycle'' features an aversion. Much of the story deals with the fact that vital information can't travel FTL unless using an unmanned vessel that goes FTL itself. The Amnion do briefly try to use some sort of experimental "symbiotic crystalline resonance device" as an FTL Radio, which becomes an important PlotPoint.

* In some of Creator/SeanWilliams's "d-mat" stories, there is interstellar travel via teleporter beam, which became much more practical once somebody invented a method of transmitting the signal FTL. The short story "The Road to Tarsus" describes a case of LightspeedLeapfrog resulting when people travelling via the new method arrive at their destination years before people who set out at light speed before the new method was devised.

* [[{{Wiki/SCPFoundation}} SCP-179]] is a rare [[{{SealedGoodinaCan}} Thaumiel]]-class humanoid woman named "Sauelsuesor" located roughly 40,000 kilometers below the south pole of the Sun. After a drone is sent to her location, an interview takes place via radio-waves with the log stating that sixteen minute delay between speakers have been omitted for the sake of brevity.

* [[{{Website/SCPFoundation}} SCP-179]] is a rare [[{{SealedGoodinaCan}} Thaumiel]]-class humanoid woman named "Sauelsuesor" located roughly 40,000 kilometers below the south pole of the Sun. After a drone is sent to her location, an interview takes place via radio-waves with the log stating that sixteen minute delay between speakers have been omitted for the sake of brevity.

* [[{{SCP Foundation}} SCP-179]] is a rare [[{{SealedGoodinaCan}} Thaumiel]]-class humanoid woman named "Sauelsuesor" located roughly 40,000 kilometers below the south pole of the Sun. After a drone is sent to her location, an interview takes place via radio-waves with the log stating that sixteen minute delay between speakers have been omitted for the sake of brevity.

*** In the Extended Edition opening, one of the colony higher-ups on LV-426 says that "[i]t takes two weeks to get an answer out here", implying that the speed of messages is no more than one week either way (as the delay may be partially due to ExecutiveMeddling or other delays on the end of the replier).

In some cases, a Subspace Ansible may exist even if FasterThanLightTravel does not. There might be some attempt to [[JustifiedTrope justify]] this, proposing that technology exists to bypass the limits of relativity for information but not matter, but often, it is simply a matter of necessity: although a single-star-system SpaceOpera can get by without FasterThanLightTravel, it takes several minutes for radio waves to travel the distance from Earth to ''Mars'', so the problem of communication remains pressing even if FasterThanLightTravel can be safely shelved.

* In ''{{Series/Eureka}}'', after Fargo and Henry build an FTL drive, the government starts planning the ''Atraeus'' mission, the first manned flight to Titan. One episode involves a scientist trying to build a Subspace Ansible for real-time communications and telemetry with the ship. Given that this is Eureka, this ends up causing a big problem (although, not by itself).

* ''VideoGame/StarControl'': the [[StarfishAliens silicon-based]] Chenjesu are described as natural hyperspace communicators. The franchise features also the typical (artificial) FTL 'casters,in seemingly real time.

* ''Literature/TheGapCycle'' averts the trope, as much of the series deals with the fact that many of the assumptions and actions are formed by the inability to communicate across the vastness of space quickly.

* ''Series/TheVorkosiganSaga'' is an aversion, as all communication has to be delivered by ships going through wormholes.

* Downplayed in Mecha Ace by Creator/ChoiceOfGames. It never gets mentioned in the main story, but if you read through the tech database it explains that ansibles are very rare and use [[QuantumMechanicsCanDoAnything quantum entanglement]] to allow instantaneous communication between planets in different solar systems.

** Communicating over long distances is important for the crew of the [[Series/StarTrekVoyager USS Voyager]], as they're stuck on the other side of the galaxy (and presumed dead), so even subspace communication won't work. After several failed attempts, they eventually succeed via LostTechnology and AppliedPhlebotinum (as well as physically moving closer in the mean time).

* The ''MightyMorphinPowerRangers'' communicators, which are connected to the Command Center's [[TeleportersAndTransporters teleportation system]], can communicate across incredible distances.

''Fanfic/TheWarOfTheMasters'' uses quantum entanglement technology for interstellar communication.

''Fanfic/TheWarOfMasters'' uses quantum entanglement technology for interstellar communication.

* In ''ComicBook/{{Legion Of Super-Heroes}}'' comics, communications are relayed through the same Stargate system used for FTL travel, making it possible to have a real time conversation between Legion HQ on Earth and the Legion Outpost in deep space. In the post-Zero Hour, pre-Infinite Crisis Legion, when the Stargate system goes down, people can still travel in "old fashioned" warp vessels, but the only means of communication is Titanet, a relay of Saturnian telepaths.

The term "ansible" for this kind of near-instantaneous subspace communication system was coined by Creator/UrsulaKLeGuin in her 1966 novel, ''Literature/RocannonsWorld''. "Ansible" is a derivation of "answerable,"; i.e., "messages will be answerable in realtime."[[note]]Others have noted that, either by accident or design, "ansible" is an anagram of "lesbian."[[/note]] Many other science-fiction writers picked up the name after Le Guin.

[[folder: Anime & Manga ]]

* In ''Film/SpaceBattleshipYamato'' the Yamato has one, but its range is limited to within the Milky Way. Okita gives everyone one minute each to say goodbye to their relatives on Earth before they continue on.
* Inexplicably possible in the Soviet two-part sci-fi film ''Film/MoscowCassiopeia'', where the teen cosmonauts are able to attend classes via teleconference while in interstellar space. Later, when they end up traveling at near-light speeds and end up at their destination early (from their viewpoint), they talk to mission control back on Earth in real-time. There is also the moment where [[TheMenInBlack IOO]] uses a rotary pay phone and a metal cigar case to show real-time footage of the starship to TheCaptain's parents, but his abilities appear to be far beyond what's possible even in the film's science.

* The TropeNamer appears in most of Creator/UrsulaKLeGuin's ''Literature/{{Hainish}}'' novels. Le Guin devised "ansible" as a contraction of "answerable."
** In ''Literature/TheDispossessed'' she tells, among other things, the story of its invention.
** In ''Literature/TheLeftHandOfDarkness'' it's clarified that the ansible needs a significant gravity source to work, so one "end" of the connection is a "stabile" and must be fixed on a planet while the "ansible" is portable.
** In the world of the Ekumen, there is no faster-than-light space travel, but there are FTL weapons. No living thing can survive FTL but unmanned ships have no problem. In ''Literature/RocannonsWorld'', there are FTL ships packed with bombs whose pilots are effectively suicide bombers, ready to sacrifice themselves in a case of dire emergency.
** Later into the cycle the problem of the FasterThanLightTravel gets solved, but as the means to do so are both [[TelepathicSpacemen psychic]] and [[JourneyToTheCenterOfTheMind mystical]], the results are... varied.

* Creator/RichardKMorgan's ''Literature/TakeshiKovacs'' series features "needlecasts", but no FTL travel. Interestingly, since BrainUploading is routine, people may travel from planet to planet by downloading into a local body.
** The information-only aspect is a power limitation, not an inherent limitation of the functionality. The information is transmitted by energy; the best matter-energy conversion reactors they have can hold open a needlecast portal for at most 15 to 30 seconds, and transmit only blinking light. They find a stable Franchise/{{Stargate|Verse}}-style portal created by the precursors, extrapolate the energy costs, and realize that a hiccup in the portals matrix would crack the planet open like an egg. Hazards of children playing with adult toys.
* In ''Literature/TimeForTheStars'' by Creator/RobertAHeinlein, telepathy is used for instantaneous communication. Eventually, scientists studying the process learn how how it works well enough to create FasterThanLightTravel as well.

* In the ''Literature/TowerAndTheHive'' series by Anne [=McCaffrey=], PsychicPowers not only provide interstellar communication, but interstellar ''travel'' by psychokinetic [[TeleportersAndTransporters teleportation]].
* In the Charles Stross novels ''[[Literature/TheEschatonSeries Singularity Sky]]'' and ''[[Literature/TheEschatonSeries Iron Sunrise]]'', FTL communication is possible through the use of quantum-entangled particles, however: a) the communication is only possible between paired transceivers, and b) taking "qbits" through an FTL jump destroys the entanglement. This means that useful interstellar communicators have to be shipped the long way 'round, making them ''very'' expensive. (Stross has [[http://www.antipope.org/charlie/blog-static/2010/09/books-i-will-not-write-4-escha.html pointed out on his blog that this situation]] -- where ''setting up'' the communication network is a long and expensive process, but ''once it's done'' it's a much faster alternative to travelling if you can afford it -- is exactly parallel to intercontinental telegraph and steamships.)
* Curious version in Creator/JamesBlish's short story "Beep" (later expanded into the novel ''The Quincunx of Time''). Ansibles are common and cheap to use, if you can stand the loud and annoying beep that accompanies every one. Due to quantum effects, the title beep contain every message that ever was or will be sent, ever, and they can be heard if slowed way, way down and appropriately filtered. The government's primary purpose is to ensure that the events described in the beep come to pass at all costs, to prevent a paradox from prematurely ending the universe.
* The Fatline in Dan Simmon's ''Literature/HyperionCantos'' uses modulated neutrinos (or some such {{Phlebotinum}}) to send messages instantly across interstellar distances. At the end of the second book [[spoiler: God(?) revokes their radio privileges completely, since the transmission medium (the Void Which Binds) is disrupted everytime a message is sent.]]
* Creator/AlanDeanFoster:
** Foster uses the SubspaceOrHyperspace version in his ''Literature/HumanxCommonwealth'' series. "Space plus" is hyperspace and is used for FasterThanLightTravel - it can also be used for communication but at the same speed as starships. "Space minus" is subspace and can be used for near-instantaneous communication, but at a very high energy cost. Later in the series, it's revealed that SufficientlyAdvancedAliens figured out how to travel in space minus as well.
** In his remake of ''Design for Great-Day'', Foster's Solarian Combine is a kind of galactic HiveMind created as a natural extension of intelligent beings learning to live and think in harmony. Said thought processes apparently travel instantaneously, ignoring the speed of light. Of course, they've learned to circumvent this with starships as well; the Combine's ships can traverse a galaxy in a matter of hours, and intragalactic jaunts are considered to be fairly trivial, if not entirely routine.
* Though it never actually comes up, the ''Literature/{{Discworld}}'' series has a bit of fun with this in a footnote. It points out that a Disc philosopher decided that the fastest thing in the universe is ''monarchy'', noting that regardless of distance, the ''instant'' a monarch dies, the heir immediately succeeds them. He further proposes subatomic particles--kingons, or perhaps queenons--but his rough-hewn plans for artificially generating them by torturing a minor noble and using them to send messages vast distances were cut short when [[spoiler:the bar closed.]]

** Some ''DeathWorld'' novels (which, supposedly, take place in the same universe) feature portable psychic locator beacons. Also, every ship is equipped with a psychic transmitter/receiver, making actual psychics obsolete.
* Heightened stellar activity can interfere with FTL communications in the ''Literature/WingCommander'' universe, as shown in the novel ''Action Stations'' (aka "Pearl Harbor {{IN SPACE}}"), but otherwise, the only time there's significant time lag for communicating across interstellar distances is the human steps relaying transmitted messages to/from the comm system and the people ultimately at either end of the line.
* Elizabeth Moon's ''Literature/VattasWar'' series featured the operation of these [[spoiler: as well as the sudden non-operation of them]] as a major plot point. Notably, interstellar FTL comm is possible, but not local FTL comm, due to the ansibles being full-scale space stations. [[spoiler: At least at first.]]
* In ''Literature/EmpireFromTheAshes'' interstellar "fold-space communicators" are very cumbersome, too big for sub-lightspeed craft and require exotic synthetic materials that starships aren't equipped to make. The mutineers sabotaged Dahak's and stole the only spares, so Dahak was forced to throw together a mundane lightspeed device instead in his attempts to phone home. [[spoiler:The short range of their ansible -- about a light month -- is one of the Achuultani's greatest disadvantages, forcing them to slowly advance through a system of preplanned rendezvous points and delaying reports back to their homeworld by centuries.]] Though comms with light hour range are cheap, small and common, which allows good coordination of space battles.

* In Creator/TimothyZahn's ''Literature/TheConquerorsTrilogy'', there are two possible FTL speeds for ships allowed by physics, but faster-than-light communications are impossible for humans. Humans quickly deduce, due to the coordination of the attacks, the alien Zhirrzh have a cheap, accurate method of FTL communication [[spoiler:their Elders]]. This understandably terrifies the humans. We also see a minor side-effect of this communication [[spoiler:radio waves cause Elders pain and can kill them-- which is considered an unthinkable atrocity]] caused consequences that ripple through all of the novels.
* ''Franchise/TheHitchhikersGuideToTheGalaxy'' itself has the "Sub-Etha" (occasionally written as "Sub-Ether"). In later books, it's even implied that a sort of Internet has been built upon the technology (it's used to automatically update the Guide to the latest edition).
* FTL communication in ''Literature/TheHistoryOfTheGalaxy'' books is achieved using enormous spherical orbital stations, which use powerful generators and transmitters to punch through [[SubspaceorHyperspace hypersphere]] to reach other worlds. During the heyday of the [[TheFederation Confederacy of Suns]], these were networked to create the Interstar, the future version of the Internet. As communication is vital between worlds, no one in their right mind would dare destroy an HF (Hyper Frequency) station, so they aren't even armed. A major plot-point of one novel involves a previously-unknown alien race launching a sneak attack on humanity by taking out the Interstar hub, isolating the human colonies. Ships also have their own HF generators, but those are usually not very powerful.
** Technically, it's possible for anyone with a powerful enough HF generator to send an FTL message. However, the enormous HF stations allow the creation of stable "floating" channels that enable the existence of the Interstar.
* The ''StarWars'' [[Franchise/StarWarsExpandedUniverse Expanded Universe]] has gone so far as to make its prevalence an InvokedTrope in ''Literature/TheCorellianTrilogy''. FTL communications are so commonplace that they're relatively easier to tap into, and so people sometimes use ''lightspeed'' communications over short distances (outer planetary orbits, tops) for security reasons.

* White Radio in the ''Literature/MatadorSeries''. Oddly for most of the series, it only transmits video in black-and-white; color is added on the receiving end, and looks kinda fake.
* In the ''Literature/PriscillaHutchins'' series, unlike FTL ships, which can take weeks or even months to arrive at their destination, hyperspace communication is basically instantaneous, which allows expeditions to be coordinated from back on Earth, but means that when something goes horribly wrong, people back home are forced to listen, helplessly.
* Brandon Sanderson's ''Firstborn'' book features a particularly brilliant HandWave. FTL travel is possible by traveling through something called the ''klage''-dynamic, but the speed of ''klage'' travel is inversely proportional to the cross-sectional area of what you're sending through it. So you can have real-time com from one side of the Empire to the other, but that same distance will take a ship months or even years to cross.
* In ''Literature/ArrivalsFromTheDark'', humanity learns to do this at the same time as they get FTL drives, sending instantaneous messages through [[SubspaceOrHyperspace Limbo]]. It's expensive and requires a lot of power, so the SpaceNavy mostly relies on couriers and FTL drones (they tend to be one-shot, since small FTL drives burn out after one use). In later novels, real-time video communication is possible across many parsecs. With the [[HumanAliens Faata]], while they have radio communication equipment, it's only used to communicate with the primitive races they're about to conquer, while they themselves rely on PsychicPowers for communication among themselves. Powerful bio-computers are able to communicate across light years using psychic waves, but even they can't reach across the Void between galactic arms.
* ''Literature/HaloContactHarvest'' has a fun example of this working to somebody's disadvantage. A Kig-Yar (Jackal) {{privateer}} ship finds the human colony of Harvest. All Covenant ships are equipped with a [[{{Precursors}} Forerunner]] device known as a "luminary", which scans for Forerunner energy signatures (and other factors) and automatically relays the data back to the Covenant capital of High Charity; the one here registers Harvest as having lots of Forerunner relics. Tampering with luminaries is forbidden under the pain of death (not the least reason being that they're Forerunner relics and are thus holy); the Kig-Yar attempt to do just that in order to prevent their luminary from letting the Covenant know about their discovery. They fail, which thus eventually leads to a war.

* Creator/AndreyLivadny's ''Literature/PhantomServer'' trilogy has a straight example ''without'' FTL travel, at least in the titular VR game. According to the {{backstory}}, an ancient race only known as the [[{{Precursors}} Founders]] discovered a way to send instantaneous messages through hyperspace, but sending physical objects proves impossible. In order to explore and settle the galaxy, they find an alternative solution. They build automated relativistic ships that travel to other stars and build space stations with biological reconstitution modules. After that, Founders then used BrainUploading to send their consciousnesses across the light years to be downloaded into cloned bodies. Meanwhile, the ships would mine resources on uninhabitable planets or asteroids and [[VonNeumannMachine make more of themselves]], increasing the speed of the exploration. The Founders have long since died out, or, at least, no one knows what happened to them. The game takes place in the Darg System and involves conflicts between several sentient species (primarily humans, Dargians, and Haash), none of whom possess instantaneous communication.
* ''Literature/TheRedVixenAdventures'' uses some form of instant communication, which isn't specified beyond being very expensive.

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[[folder: Literature ]]
* One of the entries in the Literature/XWingSeries has the squadron tapping in on a pirate conversation. They figure out how far apart the two conversing parties are by the length of the pauses, and by doing so, pinpoint their locations.
* In Creator/PoulAnderson's ''Literature/TechnicHistory'' novels and short stories, there is no "interstellar equivalent of radio" and all messages have to be carried by courier spaceships.
* Stephen Harper's Silent Empire Quadrilogy exists in a universe with FTL flight, but no FTL communication. This necessitates the use of psychics for communication. This universe has a thriving slave trade for the same reason.

* The Literature/CoDominium universe and ''Literature/TheMoteInGodsEye'' by Larry Niven and Jerry Pournelle.

* In Peter F. Hamilton's ''Literature/NightsDawnTrilogy'', it is possible that certain alien races have developed FTL communications, but humans certainly have not. Information is couriered around by manned starships.
** In his ''Literature/CommonwealthSaga'', constantly-maintained planetside wormholes allow very rapid transportation and communications from one end of the Commonwealth to the other. The most common method of traveling from planet to planet is by ''train'', spaceships having been made redundant.
* In ''Franchise/{{Dune}}'', the Spacing Guild is responsible for getting information from place to place. In the [[Literature/PreludeToDune books by Frank Herbert's son]], Navigators and his human twin manage to contact each other FTL with a device one of them cooked up, but that never caught on, mainly due to the unfortunate side effects (namely, the navigator half died of pressure induced hemorrhaging, while the brother actually fried his brain from the inside out). It was shown that two Navigators could communicate directly mind to mind in realtime, but they also died later.
* Creator/LoisMcMasterBujold's [[Literature/VorkosiganSaga Miles Vorkosigan]] novels use wormholes as shortcuts through space; unfortunately, there's no way to send messages through a wormhole without recording them and putting them on a ship. High traffic routes have regular courier ships shuttling the mail back and forth through the wormholes. On low traffic routes, your mail may sit for weeks for someone to come along and carry it on. Once on the other side, a message may be beamed at the speed of light to the next wormhole (if there's a permanent station there) or it may be carried on a ship the whole way.

* In Creator/IsaacAsimov's ''Nemesis'', the humans left on Earth eventually discover faster-than-light travel, but point out that there is no way to send radio waves through hyperspace. This leads to difficulties communicating with the Nemesis colonists.
* Averted in Creator/CJCherryh's Literature/AllianceUnion 'verse (including the Literature/ChanurNovels). Communications between star systems can only be done via FTL courier, and FTL travel is only possible between the outside edges of star systems. When a space ship arrives at the edge of a system and travels inwards it takes a long time for light-speed messages to reach the inner system (or vice-versa), with the time shortening as the ship hurtles forward at a considerable fraction of the speed of light.
* In ''Literature/TheLostFleet'' series, the delay in receiving electromagnetic signals plays a large role in the various spaceship battle tactics shown. For example, at the opening of the first book, Geary uses the massive delay in communication with the enemy to buy the time he needs to rearrange the title fleet for a TacticalWithdrawal. Even then, the fleet barely makes it.
* In ''Literature/{{Hellspark}}'' by Creator/JanetKagan, there is FTL travel but no FTL communication. Messages have to be physically transported, and there are severe penalties for interfering with a ship carrying mail. Expeditions planning to spend time away from the regularly-travelled routes may take unmanned message drones, but these are expensive and hard to replace, and are kept in reserve for emergencies.
* Creator/LRonHubbard's ''Literature/BattlefieldEarth'' features the Psychlo Empire, a civilization linked by the miracle of teleportation. Here's the thing, though - the rules of teleportation make opening two "links" to the same planet [[TeleporterAccident dangerous]], so the Psychlos set up a strict schedule of when their worlds can link up with the capital. This means that the disparate worlds of the empire have to function on their own for a year or more, until they reach the hours-long window to exchange communications and supplies and personnel. Aside from the inherent problems with this scenario, this means that once the protagonist bombs the Psychlo homeworld into a new sun, there's no way for the rest of the empire to know about this until they try to open a teleport link to it and instead get a facefull of atomic fire.
* In Creator/JohnScalzi's ''Literature/OldMansWar'' trilogy the CDF is only able to communicate between systems using courier drones.

* The lack of FTL sensors and communication in the ''Literature/StarCarrier'' books despite the presence of FTL travel both limits and allows certain tactical maneuvers, such as the standard opening move when a fleet arrives to a system controlled by the enemy involving the launch of several fighter wings at near-c velocities with the rest of the fleet following at slower speeds. The idea is that the enemy, also lacking in FTL sensors would only get a few seconds' warning of the arrival of the fleet before an AlphaStrike of nuclear-tipped missiles launched by the fighters at relativistic velocities wipe out a good number of their ships. Communication between system is achieved by courier ships that have better FTL drives.
* Creator/GeorgeRRMartin's "Thousand Worlds" ScienceFiction setting has mankind spreading across a swath of the Milky Way in faster-than-light starships, but communications between planets in different star systems can only be accomplished by plain old snail mail. One novella ("Nightflyers") mentions an information packet that was in transit from a distant world to the protagonists' planet for ''twenty years''.

[[folder:Anime & Manga]]
* Communication across large distances is virtually impossible in the ''Anime/{{Macross}}'' universe; it is actually a plot point in ''Anime/MacrossFrontier'', where even relay buoys must contend with "fold interference" that delay or disable communication entirely. However, the [[NeglectfulPrecursors Protoculture]] and the Vajra have their ways around that (see above).
** This actually seems to be a retcon. Earlier series had more or less instant FTL communication across the galaxy to the point that various fighter and ship designs were completely standard thanks to simply downloading them via a galaxy spanning internet. It was also specifically stated in ''Anime/{{Macross 7}}'' that the issue wasn't that no one knew what was going on, but that even with a call for aid it would take months at best for anyone else to arrive to reinforce the colony. The sudden addition of all these range limits and interference and such in ''Frontier'' really came out of nowhere seemingly driven entirely by rule of drama.

[[folder:Films -- Animation]]
* The time taken for messages to reach to the other recipient is practically the entire point of ''Anime/VoicesOfADistantStar''. Mikako and Noboru are separated by FasterThanLightTravel without a corresponding method of faster-than-light communication, meaning that Mikako's messages take first a month, then six months, then eventually ''eight years'' to arrive. Only at the very end, when Mikako has been stranded in space for eight years and Noboru, now twenty-four, has finally gotten assigned to a spaceship himself, does the fleet finally gain FTL communications capabilities.

[[folder:Films -- Live-Action]]
* ''Film/{{Alien}}''. The Nostromo and other ships are out of contact while on the frontier, and are thus on the spot, for taking on the terrors that wait on whatever God forsaken planet the crew finds themselves on.
** However, the sequel, ''Film/{{Aliens}}'', explicitly uses FTL communication, as the ''Sulaco'' is expected to report back to Earth on a daily basis, and the lost contact with Acheron is noticed after a matter of days, not decades. Since this communication is not explicitly accomplished by means of FTL drones or somesuch, the presence of an ansible is implied.
*** In the Extended Edition opening, one of the colony higher-ups on LV-426 says that "[i]t takes two weeks to get an answer out here", implying that the speed of messages is no more than one week either way (as the delay may be partially due to ExecutiveMeddling or other delays on the end of the replier).

[[folder:Live-Action TV]]
* Notable in its absence in ''Series/{{Andromeda}}'', where communication over interstellar distances requires a living courier.
** It's mentioned that they attempted to use Slipstreams for FTL radio, but that it didn't work very well, so they went back to couriers.
** This is because Slipstream is highly unstable. Traveling through it requires one not only to be a good pilot but to be ''lucky'' (something about quantum physics). It is stated several times that a machine, even an AI, is unable to successfully navigate in Slipstream, as machines can't guess. An attempt was made to map out Slipstream, but it failed.
** In one episode, [[TheCaptain Hunt]] laments the need to wait for a reply when the ''Andromeda'' is more than a few light-minutes away.
--> '''Dylan Hunt:''' I hate physics.
* ''Series/{{Battlestar Galactica|2003}}'' apparently relies solely on radio ([[CallARabbitASmeerp referred to in-story]] simply as "wireless") for ship-to-ship communication, and faster-than-light comm does not exist; ships on recon missions must be provided with rendezvous points before departure lest they never be able to find the fleet again.
** However, the presence of some kind of FTL transmissions is implied with the Cylons. They possess tracking beacons mentioned early on that can be traced after an FTL jump (see the Olympic Carrier in the first regular episode), plus the very nature of Resurrection technology requires FTL transmissions, as the Resurrection ship/hub is often shown as being in different ''star systems'' from the point of the Cylon's death and yet works relatively fast.
** It's shown in the pilot that the colonies actually ''possess'' this tech, but Galactica and it's fighters were specifically built without it during the first war. The reason is shown clearly when all the newer ships are remotely hacked and effortlessly destroyed by the Cylons.

[[folder:Tabletop Games]]
* ''TabletopGame/{{Traveller}}'', where all interstellar messages have to be delivered by courier (although those can still jump). This has a natural impact on the way the universe works.
** Deliberately invoked in The Fifth Frontier War, a tabletop board game based on the Traveller universe. Players were required to plot moves multiple turns in advance. The presence of Admirals, intelligence gathering, or other factors could reduce the preplanning by one or two turns.
*** Note that this is almost exactly the same problem faced in H. Beam Piper's universe.
* ''{{TabletopGame/Warhammer40000}}'' again. The Tau have FTL travel, but since they don't have psykers like the Imperium or Eldar they have to bounce their signals off relay beacons the old-fashioned way.
** Taken to hilarious extremes with Da Orks. They have FTL travel too (sort of) but in terms of communications technology [[SchizoTech they fluctuate between]] "FM radios" and ''war drums''.
* The "Pony Express" style system can also be used in ''TabletopGame/BattleTech''. It was the only way to communicate before the advent of the Hyperpulse Generator (noted above in the aversion-free section), and also experienced resurgence during the recent "Dark Age" where sabotage against the entire HPG network effectively disabled a significant majority of it. It's also used for backwater worlds without a HPG.
* In ''TabletopGame/{{Mindjammer}}'' 2-space can be used for FTL travel but not communications, in most systems the local [[TheAlternet Mindscape]] is kept synchronized with the rest by use of ships called Mindjammers that download a complete copy of the Mindscape each time they leave a system and upload as they enter a new one. The only exceptions are the Core systems connected by [[PortalNetwork 3-space FarGates]].

[[folder:Video Games]]
* ''Franchise/{{Halo}}'': For most of its history, the UNSC had to rely on FTL ships to carry messages between planets. ''Literature/HaloContactHarvest'' describes this as being like the Pony Express. As noted elsewhere, the UNSC eventually develops the technology to play this trope straight by the time ''VideoGame/HaloReach'' takes place.
* The Liir (dolphin-like aliens) from ''VideoGame/SwordOfTheStars'' use communication drones equipped with FTL engines. For gameplay reasons, there is no delay even at very long distances that require many years for the ships themselves to cross. (In game, the engines work by teleporting the object an enormous amount of times per second by small amounts, so that the ship is technically not accelerating or moving, but appears to go at up to FTL speeds.)
** The drones have a much smaller mass, meaning teleportation calculations would be much quicker (i.e. faster "movement").
* In addition to allowing starship travel, the [[PortalNetwork jumpgate network]] in the ''VideoGame/{{X}}-Universe'' series acts like a subspace ansible, allowing lightspeed radio signals to travel across the galaxy fast enough for real time communication. (This is mainly because a sector's gates [[SciFiWritersHaveNoSenseOfScale are rarely more than 100 kilometers apart]].) The fact that this is not true FTL communication becomes a plot point: after the gate network shuts down following ''X3: Albion Prelude'', interstellar communication in real time becomes impossible and all organized interstellar governments in the X-Universe[[note]]except the Earth State, whose population is mainly confined to the Sol System[[/note]] break up instantly. In the ''X-Encyclopedia'', it's stated that several 16 years after the jumpgate network collapse, the Paranid Empire managed to contact Argon Prime and Nishala, the former seats of the Argon Federation and Kingdom of Boron, via drones traveling near the speed of light.

[[folder:Web Comics]]
* In Webcomic/{{Freefall}}, it's specifically said that the only way to communicate between star systems is by sending messages via ship. As most interstellar travel is via sublight vessels (FTLTravel being quite expensive, and possibly dangerous going by the drive's name: Dangerous And Very Expensive [[[FunWithAcronyms or DAVE]]] drive), this means that a message and its response could take up to many months, as the ship carrying it travels on its normal route.

!!Aversions Without FTLTravel

[[folder:Anime & Manga]]
* ''Anime/{{Planetes}}'' features a phone on a lunar colony with a Windows-esque progress bar on a video screen that gives the delay between messages between the Moon and Earth (about a second and a half)
* ''Anime/StellviaOfTheUniverse'' has this as a plot point. Videomail between Foundations travels slower than light, so it takes hours for the messages from Shima and Rinna to reach each other.
* ''[[Anime/VoicesOfADistantStar Voices of a Distant Star]]'' subverts this by structuring the entire plot (and title of the work) around the delay in communication.

[[folder:Film]]
* In ''Film/{{Passengers|2016}}'' after Jim is accidentally woken up 30 years into a 120-year voyage on a SleeperStarship he sends an email to the customer service office for the company that built the ship, and then the computer says the message will take about 25 years to reach Earth and a reply should arrive in 55 years. And he just spent six thousand dollars on that one transmission.

[[folder:Literature]]
* ''[[Literature/TheSpaceOdysseySeries 2001: A Space Odyssey]]'', in which an interview with astronauts on their way to Jupiter has to be edited together to remove the long delay times in the conversation.
* Creator/GregEgan's ''Literature/SchildsLadder'' features a universe with neither FTL communication nor travel. Being written by Greg Egan, most interstellar travel is done by transmitting your [[BrainUploading mind]], with only a few "anachronauts" crawling around in starships to investigate the future they find along the way; either way all travellers are doomed to miss decades of time. One planet solves the problem by putting the entire population into what amounts to slow-motion until the traveler returns.
* Creator/MikhailAkhmanov and Christopher Nicholas Gilmore's novel ''Literature/CaptainFrenchOrTheQuestForParadise'' averts both interstellar communication and FTL travel. In this 'verse, space travel is a rarity due to the prohibitive costs involved. Also, while there is a way for a ship to jump to near-light speeds that make it seem only seconds pass for the traveler, decades (sometimes, centuries) pass for everyone else. It also requires one to move to the edge of a system on sublight (several months) before activating the drive in order to avoid CriticalExistenceFailure. The titular character mentions that, in 20,000 years (aging has been "cured" long ago) of traveling through space, he has intercepted about 20 interstellar messages (sent via ordinary radio), and none of them contained anything of value to him. He explains that building and maintaining large orbital arrays is too costly for most planetary governments, much less private persons, and provides virtually no return on the investment. The only people to travel between stars are colonists on one-way trips, occasional missionaries, and space traders. There are only a few hundred space traders in existence, and all are treated as royalty on most worlds, as they are the only ones who bring news from other worlds (even if those news are centuries old).
* The ''Literature/RevelationSpaceSeries'' lacks either FTL traveler or FTL communications; interstellar travel is only possible via impossibly precious lighthuggers that can continuously accelerate at roughly 1g for years with the use of the BlackBox Conjoiner Drives. The plot of ''Literature/RevelationSpace'' is kicked off when the ''Nostalgia For Infinity'' arrives at Yellowstone, the [[EndOfAnAge former hub]] of human civilization, searching for Dan Sylveste in order to coerce/hire him to save the ship's [[CyborgHelmsman cyborg captain]] from the [[TheVirus Melding Plague]], not realizing that Sylveste left the system thirty years prior.
* The ''Literature/GreatShip'' universe being MundaneDogmatic, lacks either FTL travel or communications. The scientists that seized control of the derelict [[PlanetSpaceship Greatship]] routinely beam messages back to Earth via communication lasers which will take over a thousand years to be received. The huge communication delays are generally no more than an annoyance because, hey, you're TransHuman and [[TimeAbyss are gonna outlive civilizations]]. It does however become a plot point at the climax of ''The Well of Stars'', where [[spoiler: the Greatship is seized by {{Starfish Alien}}s and its true reactionless engines are activated; it'll take a human fleet thousands of years to catch up with the Greatship as it flies into intergalactic space]].
* Implied in the ''Literature/RedDwarf'' novel ''Better Than Life'', in which the delay caused by talking to someone through time dilation is compared to making a person-to-person call to Mars.

[[folder:Video Games]]
* Usually, the ''Franchise/{{Metroid}}'' games avoid this by having no form of communication through space, but in ''VideoGame/MetroidPrimeHunters'', it's stated that a signal was sent to various bounty hunters via a telepathic frequency.

[[folder:Web Original]]
* Our universe in ''Literature/FineStructure'' used to allow FTL communication (and FTL travel), and nobody knows when [[spoiler: the Imprisoning God excised FTLC from reality.]] That is the reason there are only nine FTLC engineers on Earth.
[[/folder]]

[[folder:Western Animation]]
* In the episode "All This and Gargantua-2" of ''WesternAnimation/TheVentureBrothers'', there is a "conversation" between Sgt. Hatred on Earth and Dr. Venture on an orbiting space station. In a subversion of ContinuityEditing, lines are weirdly repeated, and they talk over each other.
-->'''Sgt. Hatred:''' Doc, I am calling from ''Earth''. There's like a huge delay; will you just wait for it?
[[/folder]]

[[folder:Real Life]]
* RealLife, so far. [[http://www.colbertnation.com/the-colbert-report-videos/167610/may-08-2008/garrett-reisman This clip]] shows how tricky surface-to-orbit conversations can be without an ansible to hand.
** Even Digital Satellite TV (e.g. [=DirecTV=], Dish Network) is delayed about 4 seconds relative to the cable feed the shows come from. This delay is mostly due to the processing time necessary to compress the data on-the-fly, however; the actual signal-propagation delay to and from the satellite is only a quarter of a second.
* As of 2 December 2011, scientists have discovered that [[http://www.livescience.com/17264-quantum-entanglement-macroscopic-diamonds.html quantum entanglement is possible in macroscopic scale]]. Quantum entanglement experiments make it seem as if systems are somehow "communicating" faster than light through correlations between their states, although if quantum mechanics is correct it's (provably) impossible to actually use this to send information faster than light.
** The reason why quantum entanglement cannot be used for FTL communication is this: imagine you have two entangled particles. Particle A is with you and Particle B is many light-years away. Obviously, you can easily measure Particle A to find out something about its state (say, its spin). Once you know the spin of A, the spin of B is determined and anyone measuring the spin of B will definitely measure the opposite of what you measured. To use this for communication, you would have to somehow "force" particle A to take on a certain spin. But, this is fundamentally impossible as any interference will collapse the particle's wavefunction, breaking the entanglement.
*** However both China and ISS partnership claimed to have had some success changing one atom and having the other one change. China claims to have even successfully communicated with its satellite no if ands or buts. It should be mentioned that the exact details of these experiments haven't been released yet and China was more interested in using quantum entanglement communication [[MundaneUtility to make hack proof communications than FTL communications]].
** In other words, imagine you take two cards: the ace of spades and the ace of diamonds. You shuffle them, give one to your friend, then fly to the other side of the solar system. By looking at your card you know instantaneously what card she had (because it needs to be the opposite of yours), but no information was transmitted.
* This trope is OlderThanTheyThink:
** One solution to UsefulNotes/TheLongitudeProblem, which similarly involved trying to transmit information (Greenwich Mean Time) over vast distances (the ocean) beyond the scope of modern technology (handwritten letters), was to keep a wounded dog in a cage on a sailing ship. A person in London would dip its bloodied bandage into what was called "[[SympatheticMagic the powder of sympathy]]" at a prearranged time, whereupon the dog would yelp at the same instant. In case it wasn't blindingly obvious, this theory never caught on with the scientific community.
** Similarly, grisly rumours, perhaps inspired by the "powder of sympathy" theory, emerged during the Cold War that both the USSR and USA were testing out the fringe idea that psychic communication not only worked, but worked instantaneously, by separating a mother animal from her newborn young, which went to sea on a submarine whilst the mother stayed at home in a research lab. At prearranged times, one of the baby animals would be killed whilst the home lab monitored the mother for a sign of sudden unmistakable distress. Baby rabbits and kittens have been suggested as the most likely test subjects.
[[/folder]]

* ''Literature/WeAreLegionWeAreBob'': Everyone uses the SURGE drive, a reactionless drive that somehow uses subspace to accelerate to ridiculous speeds in realspace. In theory, it could be used for communication, though the people of Earth haven't bothered to look into it. Bill decides to stay behind in Epsilon Eridani to work on it. [[spoiler:He manages to invent an instant subspace radio with a range of twenty-five light years, but unfortunately it needs a working transponder on both ends to work. He sends off plans for the first version to the other Bobs as soon as possible, but by the end of the book only Riker's group has received the plans and built a relay. In the second book, more Bobs have built relays, creating an instantaneous network across dozens of lightyears or, as they like to call it, [=BobNet=]. Bill has a standard hazing ritual, whenever a new Bob joins [=BobNet=] by popping up in the newly-joined Bob's personal VR. The original Bob notes that Bill still omits the fact that the system has enough bandwidth for interstellar VR in order to pull this trick on every Bob]].