Subspace or Hyperspace are terms used in science fiction to describe certain forms of space that can do things impossible in regular space (see also Green Rocks).
Subspace was popularized by Star Trek and is a trope for a form of space that has different physical properties from normal space and allows the Enterprise crew (and the writers) to do all sorts of things that have some degree of scientific "consistency" but can't actually happen in the real world. For example, generating a subspace field can alter the apparent mass of an object, allowing it to be moved more easily. It's also the basis of FTL Radio, which makes communications possible in ships that are moving faster than light (since real-life radio transmissions can only travel at light speed). It was used on Star Trek: The Next Generation and Star Trek: Deep Space Nine with regularity, often just to fill the Applied Phlebotinum slot for the episode. Star Trek: Voyager took this to silly extremes-at least one episode referenced hypersubspace. Your guess as to what that means is as good as ours.
Before there was Star Trek, Golden Age science fiction would sometimes include references to "sub-etheric" communications or waves. The idea of the ether had already been disproved, but the term was useful for "waves that behave kinda like light, only different."
In the real world, hyperspace refers to mathematical concepts involving more than 3 spatial dimensions. Hyperspace or hyperdrive is often used to describe Faster-Than-Light Travel or another dimension or other scifi concepts, and as such has been part of the SF lexicon at least since the pulp magazines of the 1930s. For example, in Star Wars, it is how starships achieve faster-than-light travel. Likewise, Babylon 5 uses a hyperspace, but with a far different set of rules and base technologies behind it.
If both terms are used in a story, then typically subspace will only allow data transmissions, but will carry them almost instantaneously. Hyperspace will be slower, but will at least temporarily allow matter (spaceships) to travel through it.
The name subspace seems to be taken from the subobjects of various mathematical spaces, such as vector spaces in linear algebra or metric and topological spaces in topology. The name hyperspace was originally used to refer to vector spaces with more than three dimensions. Thus the origin of the hyperspace concept is probably linked to Another Dimension.
- In Uchuu Senkan Yamato this is where space submarines go when they "submerge". And yes, they do have periscopes to peek back into normal space with. If Space Is an Ocean, subspace is what's under the surface.
- In Crest of the Stars, it's called "Planar Space", and it is literally two-dimensional, making it rather the opposite of hyperspace. Spaceships have to generate a "space-time bubble" around themselves to avoid ceasing to exist as spaceships and getting irreversibly turned into exotic particles. Ships can only enter or exit Planar Space at naturally-occurring gates (called "Sords"), and distances and locations in Planar Space does not correspond in any meaningful way to distances or locations in normal space, though it is for the most part a great deal shorter and all those explored so far have exited into the Milky Way galaxy.
- Scott Pilgrim: Ramona Flowers uses Subspace to get around quicker for her job as a delivery girl, and owns a Subspace handbag. Ramona specifies that it's not the same kind of subspace featured in Super Mario Bros. 2, where it was essentially a Dark World, and not really this trope.
- The Authority has a ship that exists in and travels through "The Bleed"- a seemingly endless expanse of red void that lies between (and connects?) each and every dimension for DC and Image Comics, and possibly even Marvel and Dark Horse Comics.
- Most Marvel Comics teleporters use some form of subspace to accomplish their teleportation - they jaunt to subspace, move a short distance, then come back out having covered vast distances. It is also stated in the original Official Handbook of the Marvel Universe and its subsequent variants that most characters with some form of growth draw the extra mass from there, while those who shrink store their shed mass there (until they reach a certain size limit, when they suddenly 'slip' into a different universe).
- Grant Morrison's JLA reveals that hyperspace, known to the White Martians as the Still Zone, to Prometheus as the Ghost Zone, and to the Queen Bee as the Honeycomb, is also the Phantom Zone used as a prison on Krypton and Limbo (as in, the place you go when you die if you weren't good or evil enough to go directly to Heaven or Hell).
- Green Lantern: Green and Red Lanterns use Hyperspace to travel across the universe.
- In the Green Lantern/Supergirl crossover Red Daughter of Krypton Supergirl jumped into Hyperspace to go from planet Mongo to Earth.
- The Next Frontier has some fun with this one. Despite explicitly using an Alcubierre Drive, which in some ways could be described as a Defictionalisation of a Star Trek warp drive, the narrative pointedly uses "hyperspace" instead of subspace. Quoth a plaintive footnote:
Anyone complaining that Star Trek calls it "subspace" can Google that word with Safe Search turned off and see if they can keep a straight face next time they hear it.
- Thousand Shinji: The main characters use the energies of the Warp -a parallel dimension- to transform themselves and draw psychic and sorcerous power. However, it's severely restricted due to the machinations of the Necrontyr.
- In the Star Trek: Enterprise Parody Fic Farce Contact, Subcommander T'Pol mentions running a Subway franchise on Earth in order to study subspace.
- David Brin's Uplift novels have five different "levels" of hyperspace, each one seemingly more bizarre than the last and host to its own strange forms of life. In the meme level of hyperspace, bizarre biological transformations and even Ret Gone are common hazards.
- Hyperspace comes in a variety of "bands" in Weber's Empire from the Ashes, though the only difference between them seems to be the speed limit. Ships must maintain stasis fields during travel; if the field is broached, the ship is destroyed without a trace. Ships in normal space can detect ships traveling in hyperspace but not the other way around, allowing the creation of undetectable (to their targets) mines that warp into hyperspace to disrupt the stasis fields of ships passing over them in hyperspace. Achuultani ships use the slower hyperbands, but their missiles cover all of the bands, making them much harder to block.
- In the Honor Harrington series, starships can enter Hyper and travel at effective FTL speeds as distances in Hyper are shorter than in realspace. The "higher" the Hyper band, the greater the speed-multiplication. Dangers include Gravity Waves and "walls" between different levels of Hyper.
- Neal Asher's Human Polity series has Null Space, exposure to which drives an unprotected human quite mad.
- John Meaney's sci-fi books (such as the Nulapeiron sequence) feature Mu Space, a fractal continuum (because 4 dimensions are dull compared to an infinite number of dimensions). Once again, exposure to mu-space by normal humans tends to result in screaming insanity, though both cybernetic and genetic pilots can navigate it without problem. The former are blind, another common theme...
- Alan Dean Foster's Humanx Commonwealth stories feature both in the form of space-plus and space-minus. Space-plus is what ships travel through while space-minus is what communications travel through. Space-minus travel is faster than space-plus travel but any objects sent by space-minus get turned into soup. Later novels reveal that the Precursors figured out how to travel through space-minus and even more exotic things.
- Foster's version of how "subspace" works bled over into Star Trek due to his writing the Star Trek Log series of animated series novelizations in the Seventies.
- In the Star Wars Expanded Universe, Subspace is sometimes used for communications and sensors, but has shorter range and is slower than Hyperwave, making this a subversion, as both Subspace and Hyperspace can be used for Sensors, Communications and Travel, but Hyperspace is unilaterally faster.
- In the Animorphs series, "Zero-space" or "Z-space" is supposed to be anti-space which can be used for faster-than-light travel. However, it also shifts, so how fast it can take you to a given location may vary. (This is part of the reason why Earth isn't getting much help from the Andalites for most of the series.) This is also where Shapeshifter Baggage goes and where new matter comes from. Don't worry; the chances of a stray spaceship hitting your spare mass when you're in morph is infinitesimally small. Yes, of course it still almost kills our protagonists at one point.
- Iain M. Banks's Culture novels feature two types of Hyperspace: Ultraspace and Infraspace. This is a result of the description of the nature of the Universe in those novels - as the Universe expands, other Universes are expanding "inside" it (in a multi-dimensional analogue of a kind of expanding onion, with the individual layers of the onion representing Universes). Hyperspace is found "in between" the Universes, with Ultraspace defined as the Hyperspace between a Universe and the one "above" it and Infraspace being defined as the one between a Universe and the one "below" it. The current method of travel amongst The Culture is to alternate between the two, accelerating first in one then switching to the other over and over until max speed is reached, then sticking with whichever is desired. Interestingly, these spaces appear to have a plasticity — a ship that is accelerating hard or breaking hard is described as creating churning waves in whichever space it's in.
- Then there's the Excession, which shocks every AI Mind which sees it as it is somehow connected to Infraspace and Ultraspace simultaneously, acting as a bridge between three universes at once.
- John E. Stith's Redshift Rendezvous features several levels of Hyperspace in which the universe is progressively smaller and the speed of light decreases with each step. The story is largely concerned with a murder mystery on a spaceship traveling in the level where the speed of light is 10m/s and relativistic effects are a part of everyday life.
- In 50 Great Short Short Science Fiction Stories one of the short stories deal with breaking through to hyperspace only to discover that it is slower than light speed and thus useless.
- All FTL travel in The History of the Galaxy is done through a dimension/anomaly called "hypersphere". Unlike the mathematical term, which simply means a sphere in more than 3 dimensions, this hypersphere is more like your typical sci-fi hyperspace. It exists alongside normal space/time and appears to have a spherical shape (with our galaxy surrounding it). Like any sphere, it has a center, and several later (timeline-wise) novels deal with what's located there and the impact it has on interstellar travel. The properties of hypersphere are stated in most novels, with novels dealing with the nature of hypersphere going into more detail. Of note is the fact that humans are one of the few known races to have developed hyperdrives (although the discovery of hypersphere itself was a complete, and tragic, accident, involving the disappearance of the first extrasolar colony ship). Most other races have learned to use the "horizontal" force-lines in hypersphere (they connect large stellar bodies such as stars or planets) as tunnels of sorts, creating a Portal Network. While they don't need ships to travel from planet to planet, they are limited to the network, until their ships traveling on sublight can set up a gate in a new system. When humanity first encounters them, the aliens quickly adapt human hyperdrives for their own ships. Hyperdrives are made up of two generators: one to "submerge" a ship into hypersphere and one to "surface" it back to normal space. They are designed to be infallible and almost never break down.
- Hypersphere is also split into ten layers based on the energy levels required to reach them. However, the deeper a ship submerges, the stronger the "energy pressure" gets until a ship is crushed like an empty eggshell without strong enough shields. Most civilian ships tend to travel in the first layer, which is the slowest (or, rather, the distance between the points corresponding to normal-space locations is not as short as in other layers). Warships tend to have stronger shields and travel in the third or fourth layer. Only unmanned probes with exceptional shielding can hope to survive traveling as deep as the sixth layer. Later novels reveal what happens when one reaches the tenth layer. If one manages to do so, then the traveler reaches the very center of hypersphere, which contains a miniature projection of the galaxy from all the vertical "tension lines" converging at the location from every star in the galaxy. There are also several planets orbiting the projection, but they are not native to this location, being the result of an experiment to alien races millions of years ago to put a permanent base of operations in hypersphere in order to serve as a hub to the rest of the galaxy. By traveling along a vertical "tension line" to the center of hypersphere, one is then able to pick another vertical and "surface" in normal space at that star system. Basically, one could get anywhere in the galaxy in a matter of hours, eliminating the need for normal hypersphere travel. There is a slight caveat in that the intense energy pressure at the center of hypersphere prevents electrical devices from functioning, while also imbuing some people with magic-like abilities. Thus, all ships wishing to use this method of travel must use a mix of electronic and photonic systems. The former are used until one reaches the center, while the latter are used for navigating in this area.
- All spacefaring races in Mikhail Akhmanov's Arrivals from the Dark series use the so-called "contour drive" for instantaneous jumps across great distances. The drive sends the ship into a parallel dimension known as Limbo before making another transition into normal space at different coordinates. The power requirements are actually quite small compared to examples in other sci-fi works. The biggest problem is the difficult in calculating precise exit coordinates. The difficulty of making precise calculations is further increased by the distance of the jump and any gravity fields at both the start and end locations. Thus, jumps typically take place at the outskirts of star systems, although short-range in-system jumps are also possible to escape danger. Most ships tend to use the "short hop" system to reach far-off destinations (e.g. jump to a nearby system, recalculate, jump again, etc.). When fleets jump, they do so individually and frequently end up scattered throughout destination system. Small countour drives typically burn themselves out after a single use, and are, thus, only used in message drones. However, it's possible for a relatively small ship to be FTL-capable, as demonstrated by the three-man patrol ships (called "beyri") used by the humans hired as Defenders by the Lo'ona Aeo (on the other hand, Lo'ona Aeo technology is way more advanced than that of all other known races).
- In Valeriy Yantsev's short story "A Million Years Later", humanity discovers subspace (which first requires accelerating to near-light speeds but is instantaneous otherwise) but finds out that there is a side effect of exiting near a large stellar body, resulting in an Earth-Shattering Kaboom. After 90 years, a safeguard is developed, allowing for reliable interstellar exploration. Then a hostile alien race is discovered, and an FTL-capable ship is sent to their star system (Altair) ahead of their relativistic scout ships to gather intel. The ship's crew determines that humanity doesn't stand a chance, having been at peace for centuries, while the aliens are preparing an armada to invade Earth. The Captain and his Number Two disable the safeguards and perform a jump into the heart of the alien star, resulting in a supernova-level explosion, saving Earth at the cost of their own lives. The whole event is classified, and a million years later, people still wonder why Altair blew up for no natural reason.
- The version featured in The Princes of the Air has some unique features which form the basis for an exciting action sequence.
- David Drake's RCN series has the Matrix, a plane outside the universe packed with bubble universes with varying physical constants. Ships travel in the Matrix by using electrically charged sails that harness the single pan-universal force, a radiation that exists only in the Matrix, to transit between and among these bubble universes.
- The Alexis Carew series has darkspace, a plane overlaid on our own that is made up entirely of dark matter and features "shoals" and storms. Ships enter and exit darkspace at Lagrange points, then use sails to harness the natural flow of dark energy towards massive objects such as planetary systems. Travel is faster the further away from massive objects you are. It's also noted that nobody really understands the why of it, just how to harness the forces involved. Oh, and all navigation is done by dead reckoning using primitive methods, as electrical equipment refuses to operate outside of the ship's shielded hull.
- The Alliance/Union universe has Hyperspace travel that acts similar to (and is mostly described in terms of) Jump Drives: it's impossible to change direction while in Hyperspace, and the only way to drop out of Hyperspace is to run into a sufficiently large gravity well, so FTL travel consists of pointing yourself in the right direction, building up enough speed, hitting the "Enter Hyperspace" button and then waiting for the ride to be over. The FTL engine can also be used to briefly dip into Hyperspace in such a way that once the dip is over the starship's velocity is higher or lower than beforehand. This allows starships to rapidly go up to or down from near-light speed without smearing the crew into paste and tearing apart the ships like they were made from tinfoil.
Hyperspace is of the "Scary" variety:
- Humans are prone to suffering psychological damage unless they're tranquilized while moving through it.
- The alien stsho of the Chanur Novels sub-series will straight out die of shock if they're not tranquilized.
- The Cat Folk hani of the Chanur Novels don't need to tranquilize themselves, but do enter a dreamlike state which renders them incapable of doing any work, and when they leave Hyperspace their bodies are starving and heavily shedding.
- In the Lensman series, hyperspace is much closer than usual to its mathematical origin. Hyperspace tubes allow a ship to travel around normal space to approach a target undetected, but do not affect speed.
- In Stargate SG-1, subspace and hyperspace are shown as separate things, frequently both used and fairly consistent in their application. Subspace is used to allow near-instantaneous communications, while hyperspace is reserved for transportation of physical objects and depicted as the slower of the two. Travel via Stargate relies on using artificial wormholes to travel through subspace, dematerialising an object and sending it through a matter stream before rematerialising it, allowing for individuals to travel across the galaxy (or galaxies) in seconds, without all that tedious mucking around in hyperspace.
- Averted in Stargate Universe, where the means in which Destiny travels through FTL is unknown other than it doesn't rely on hyperspace.
- In The Tomorrow People, John theorizes that their form of teleportation involves travel through hyperspace. They later learn that Tomorrow People who do not successfully "Break out" (ie. come into their powers) get lost in hyperspace and eventually lose bodily cohesion. Elizabeth is saved from such a fate in her introductory episode. John later adjusts their Jaunting belts to "change the angle" at which they enter hyperspace, as justification for a special effect change. In the Big Finish series, one of the villains is the insane, disembodied consciousness of a Tomorrow Person who had become stuck in hyperspace.
- The matter paddle in Red Dwarf works by sending people through subspace.
- Space 1889 complete averts this. While they can use ether to travel at very high speeds indeed, they do so in perfectly regular space.
- The Warhammer 40,000 verse has an immaterial, psychic, parallel dimension known technically as the "Immaterium", colloquially (and classically) as the "Empyrean", also known as "Warpspace", the "Sea of Souls", and a number of other names, but most commonly called the "Warp". The Warp fits this trope as a hyperspace, filled with daemons, the occasional deity, space hulks, and is the source of all psychic and sorcerous power. Direct exposure to the Warp or its gradual influence causes mutation, insanity, and a high risk of Demonic Possession, and (for humans at least) the people able to navigate it are blind to normal space.
- Since you go to the Warp when you die, hyperspace in Warhammer 40k really is flying through Hell. Humans don't have a strong enough psyche to hold themselves together, so their souls will either just dissolve back into the Warp or "lose sense", intuitively becoming animalistic or comatose—assuming that they don't get eaten by Daemons before either of those can occur. The Eldar, on the other hand, can survive and remain cognizant in the Warp—and will do almost anything to avoid it, because they accidentally created an Eldar-eating Chaos God(dess?). The Warp used to be a safe place for them, but no longer. That's why they use soulstones, is to prevent them from getting into the Warp.
- While the Warp jump remains the primary means of FTL travel for many races, the Webway is a hyperspace utilized almost exclusively by the Eldar. It is made of a series of tunnels somewhere between the Warp and realspace, connecting portals from millions of locations in realspace together. It's limited in that the Webway portals are fixed and new locations must have a portal built at that location to be accessed afterwards, and that since the cataclysmic fall of the Eldar, many parts of the Webway have been destroyed, lost, inhabited by Daemons or other strange creatures and dangerous entities; yet despite all of this, Webway travel is much quicker and safer than relying on Warp jump technology.
- Yet other species have different means of FTL travel: Necrons, who use unimaginably advanced technology, go through subspace by way of their use of inertialess drives to accomplish the setting's only actual FTL travel.
- Tyranids use a subspace mean of FTL by a living creature that harnesses a neighboring planetary systems' gravity well.
- The Tau skirt the border between hyperspace and subspace, having not mastered the technology for a full translation into the Warp, "skimming" the border between space and Warpspace instead. This means that while they're safe from the stuff lurking in the Warp, their FTL is something like five times slower than Imperial Warp travel.
- The Tau can't really go into the Warp because they have no Psykers - they have no means to truly access it beyond "skimming" the divide between the galaxy and the Immaterium (whatever that means), and they wouldn't be able to navigate through the Warp even if they got there. And it turns out, even for the unpsychic Tau, being lost in Hell is a bad thing.
- Orks, on the other hand, love Warp travel, as they see the unimaginable dangers and ravenous monstrosities as welcome distractions from the monotony of getting to yet another planet to loot and burn.
- In BattleTech, travel via Jumpship is explicitly described as using a hyperspace field to translocate any jump-drive equipped vessel up to thirty light years from its previous location. Notable for making realspace gravity a very real threat when emerging from a jump, requiring Jumpships to be well away from stars and planets when jumping into a system. Similarly, the setting's Hyperpulse Generators are a kind of Subspace Ansible explicitly stated to generate hyperspace fields to transmit messages across fifty lightyears of distance.
- In Traveller jump space is always approximately a week, but distance is from one to six parsecs in that week depending on the power of the engines in a given ship.
- In Dungeons & Dragons, the Astral Plane works just like Hyperspace in many Sci-Fi settings. Everything that is Bigger on the Inside works by creating a pocket of real space inside the Astral Plane, and all spells that teleport people to other points on the same plane, or to other planes, tunnel through the Astral Plane.
- The classic computer game Elite called it Witch Space.
- In the Halo series it's called slipspace, which is described as a series of eleven dimensions of space-time through which a ship can take wormhole-style 'shortcuts' to reach their destination. It's been described as taking the 'flat sheet used to represent space' idea with two points on opposite edges and crumpling that sheet into a ball, creating new extra spaces that allow less travel time if you have the tech to move your ships into & out of those spaces. It can also be used to transmit data and communications almost instantly. Its other uses ranged from stasis to miniaturizing Dyson spheres. It is hinted that there are actually several other dimensions, although they have not yet fully been explored.
- Slipspace also has a efficiency factor. The entry into Slipspace with human and Covenant drives are compared to a butcher knife and scalpel, respectively, with war-era UNSC drives going a little over 2 1/2 light-years per day and being horribly inaccurate both space- and time-wise for 'exits', while Covenant drives are accurate on an atomic level and can reach over 900 light-years per day. The Forerunners, whom the Covenant (poorly) reverse-engineered their tech from, could travel even faster, reaching points clear outside the Milky Way Galaxy in just a few days.
- The Homeworld video game series treats hyperspace as a sort of time-delayed quantum teleportation requiring massive amounts of energy. Sometimes it goes badly.
- Star Control has Hyperspace, the standard method of interstellar travel, and Quasi-Space, which after obtaining a certain item, you are able to travel through for the cost of 10 fuel. They are described as different "layers" of reality, in which the laws of physics work a bit differently: for instance, in Hyperspace the speed of light is much, much greater than it is in normal space, allowing ships to travel faster-than-light. However, space friction apparently exists in Hyperspace, meaning ships have to constantly expend fuel rather than accelerating and drifting. Quasi-Space further has its own set of rules. Once in Quasi-Space you can move your ship without consuming fuel and go through a portal to Hyperspace, it's the most efficient method for long trips in the game.
- The FreeSpace series uses a kind of hyperspace drive (called a "subspace drive") for short range jump inside a system. For long range jumps between star systems, the same drive is used with a network of stable wormholes (called "Jump Nodes"), that are otherwise completely invisible in normal space. As a result, new star systems can only be reached if a wormhole leading to it is discovered. The last level in the first game even takes place in one of these wormholes, while the sequel culminates in a desperate plan to deliberately induce the unintended side-effect of blowing up a capital ship inside subspace - collapsing the Jump Node it is in - to cut off the new Shivan incursion from the remainder of GTVA space
- Sword of the Stars has both. Subspace, also called node space, is used by humans and the Zuul to travel between stars (humans use natural fixed tunnels, while the Zuul "dig" their own, which are unstable and collapse over time). The Tarka use hyperdrives to generate localized hyperspace bubbles around their ships to propel themseves to FTL speeds. It is possible that the Hivers' Portal Network also uses hyperspace for instant teleportation between gates. While the method used by the Morrigi is known only as either the Void Cutter Drive or the Flock Drive, it can be assumed also uses hyperspace.
- The Hiver gates are described as sending objects and messages through the "skin" of the universe. The novel Deacon's Tale claims that it's only safe for Hivers. When Cai Rui (a human) travels through a gate, he feels like he's being turned inside out.
- In the sequel, the Loa have developed their own means of FTL by combining the methods from several carbonite races, resulting in gates positioned between nearby star system that slingshot a ship or a fleet to FTL speeds through hyperspace for short while, before the ship/fleet drops out of FTL to sublight speeds, unless there is another gate in place to continue slingshotting it.
- This is the reason that faster-than-light travel works in the Star Ocean series. However, by the events of the third game in the series, Subspace warp has largely been displaced by the even-faster Gravitic Warp technology.note
- WarCraft The Twisting Nether in the Warcraft series is hyperspace in all but name. It's a series of hyperspace-like extra dimensions that connects all worlds together. Portal magic uses this to work. Also, the former world of Draenor (called Outland after its destruction) was entirely shifted into the Twisting Nether when it was destroyed by a portal storm, so it has a REALLY interesting sky.
- The story mode of Super Smash Bros. Brawl, appropriately called "The Subspace Emissary", features Subspace as an alternate dimension, home of Master Hand and Tabuu. It can be accessed via giant evergrowing purple spheres created by the supspace bombs and the subspace cannon, which draw everything they touch into it. Subspace itself is mostly a dark purple-ish void filled with purple energy platforms and spheres containing the landscapes that were swallowed up by the gates.
- A reason given by The Hitchhiker's Guide to the Galaxy for the development of the Infinite Improability Drive was to cross interstellar distances in a mere nothingth of a second, without all that tedious mucking about in hyperspace. Given that it avoided this by passing through every conceivable point in every conceivable universe almost simultaneously with the risk of picking up random hichhikers other ships had, quite reasonably, thrown into space, mucking around in hyperspace must have been tedious indeed. Hyperspace travel also also required the demolition of utterly insignificant planets in order to make hyperspatial express routes.