Future technologies

INTERSTELLAR SHIELDING
Ship Streamlining
Tech Level: 13
Ablative Shielding
Tech Level: 13
Magnetic Field Shielding
Tech Level: 14
Anti-Proton Spray
Tech Level: 16
Interstellar space is not quite a perfect vacuum, though it is very close. About one hydrogen atom exists per cubic centimeter (as compared to 10^18 atoms per cubic centimeter on Earth at sea level.)
At normal speeds, even normal deep space travel speeds, the impact of these atoms is negligible. However, during interstellar flight starting at a few percentage points of lightspeed, impacts with these atoms grows much more numerous, and thanks to the velocity of the ship they hit with far greater energy. What results is the ship’s hull being worn and eroded away, with the process happening much more rapidly the greater velocity with which one travels.
Impact with anything larger than a hydrogen atom could have catastrophic effects; a dust particle massing a single milligram would hit a ship travelling at one-third lightspeed with the equivalent force of one ton of chemical high explosives.
Also, as one approaches signifcant fractions of lightspeed, plowing through the interstellar medium may also produce a noticeable amount of drag, potentially reducing the efficiency of a ship’s interstellar drive.
Besides simply thickening the hull to prevent erosion, there are several strategies for dealing with this phenomenon. A ship could use one or a combination of the following techniques.
SHIP STREAMLINING
Tech Level: 13
A simple and straightforward strategy that may seem counterintuitive to decades of common wisdom about practical spaceship design. Nevertheless, rounding and tapering the hull and minimizing external hull structures would help to deflect the interstellar medium around the ship rather than letting it smash into the ship directly.
ABLATIVE SHIELDING
Tech Level: 13
This concept was first introduced in the novel The Songs of Distant Earth by Arthur C. Clarke. Basically, the ship carried a large shield in front of it, designed to absorb the impacts with interstellar atoms and slowly ablate away over the course of a voyage. In the novel, this took the form of a large, rounded, segmented barrier of water ice. The ship had to stop and replenish its worn shield halfway through its fifty light year voyage.
More advanced versions of ablative shielding could take the form of foamed alloys or advanced aerogels.
MAGNETIC FIELD SHIELDING
Tech Level: 14
This is a two part system. The first component consists of a powerful laser, or array of such, that shoots ahead of the ship. The laser imparts enough energy to the hydrogen atoms that their electron flies off. Then, powerful magnetic fields projected ahead of the interstellar vessel deflects the positively-charged nucleii away from the ship. A more powerful variant of this idea is used in the Bussard Ramjet interstellar drive.
ANTI-PROTON SPRAY
Tech Level: 16
An idea that comes from the novel Encounter with Tiber by Buzz Aldrin and John Barnes.
In this scheme, the ship either carries a large store of anti-protons or has the means of manufacturing them in quantity. A linear particle accelerator, much like a spinal mount weapon, runs the length of the ship, accelerating the tiny bits of anti-matter to near-light speed and shooting them out ahead of the ship in a fine, wide-angled spray.
Whenever the heavy particles encountered an atom or speck of dust, it would react with it explosively as well as impact it with tremendous relative velocity. It would be much like setting off a firecracker next to a rock, nudging the interstellar particulate out of the way of the ship. Continuous spraying would ensure an even spread that would protect all of the ship’s forward surface area.
The main disadvantage of this system would be that all that matter/antimatter interaction would create a source of gamma rays at the fore of the vessel that could be potentially damaging to the crew and ship systems. However, it is already assumed that interstellar ships would already have heavy forward shielding, so a little extra to minimize the gamma ray hazard would not be unreasonable.

BUSSARD RAMJET
Bussard RamjetTech Level: 18
The Bussard Ramjet was first conceived by Robert Bussard in 1960, and has since been used in countless literary science fiction stories and novels, such as Tau Zero by Poul Anderson, A Deepness in the Sky by Vernor Vinge, and numerous "Known Space" stories by Larry Niven.
The Bussard Ramjet concept relies on the fact that the vacuum of space is not quite as empty as we tend to think. While matter is spread incredibly thin in the depths between the stars, there still exists about one hydrogen atom per cubic centimeter (compared to the 10^18 atoms per cubic centimeter in Earth’s atmosphere at sea level.) The Bussard Ramjet uses an immense forward-facing conical magnetic field to scoop up this interstellar medium as it zooms through space, using its tremendous forward velocity to force the funneled hydrogen molecules to a fusion state at the apex of the converging magnetic fields. The super-hot fusion plasma is then expelled for thrust.
Used in this way, the Ramjet-equipped ship would never run out of fuel as long as it maintained a certain minimum velocity for the system to remain functioning. This exact minimum velocity is a subject for debate; some sources say 1% lightspeed or so, while others quote it as high as 6%. Whatever it may be, the ship would need a secondary drive system that would allow it to not only get up to these velocities without using the ramscoop but to maneuver around within a star system where significant fractions of lightspeed may prove impractical. Typical secondary drive sources from science fiction source include light sails, magnetic sails, fusion drives, and antimatter drives.

Various diagrams of Bussard Ramjet operations

Because it has a practically unlimited fuel supply, a bussard ramjet is a particularly powerful stardrive, as it can theoretically accelerate for any arbitrary interval of time, whether it be a few minute or many millennia. Very efficient ramjet drives can come to within a hairbreadth’s of the velocity of light, though some source say that a ramjet’s more practical limit may be between 50% and 85% lightspeed. Accelerating at a constant 1 g, a Bussard Ramjet could get to within a few percentage points of lightspeed within a year.
A wide-beam laser is shot ahead of the vehicle, imparting enough energy to any hydrogen atom in its path to force its electrons to fly off. The magnetic field projected by the ship attracts the positively charged ions and repels the now free electrons. The tremendous forward velocity of the ship and the tapering cone of the magnetic fields force the protons together with enough force to spark a fusion reaction. Alternately, the hydrogen can be catalyzed by an on-board antimatter supply to produce more efficient fusion reactions.
One of the main difficulties in building a bussard ramjet (aside from getting it up to the minimal operational velocity of one to six percent lightspeed) is creating magnetic fields large enough to gather enough fuel to be practical and strong enough to handle the stresses of scooping and fusing hydrogen at significant fractions of lightspeed. In order to obtain enough fuel for continual operation, the scoop would have to be thousands of miles wide and relatively narrow to aid in maintaining magnetic field strength. The strength of the field would also be immense, on the order of 10 million tesla, making them instantly deadly to any living creature. In one Larry Niven story, a bussard ramjet scoop field was used to threaten an entire planet with extinction.
Some concern has been expressed about the amount of drag the interstellar medium will induce on the ramjet. Moving at significant fractions of lightspeed, the repeated impacts of the interstellar hydrogen on the immense ramscoop field is thought by some to offset much of the acceleration produced by the fusion engines, greatly reducing the starship’s capabilities. If this is so, a ramjet’s top speed may be only 15% to 25% lightspeed. However, it has also been pointed out that the impacts would not necessarily produce nothing but waste energy, as the ramscoop uses the impacts as part of its scooping and fusion processes, so how much drag a bussard ramjet would actually experience is a matter for debate.

FTL

ANSIBLE

In the Star Wars universe, characters often communicate between star systems using an ansible-like holographic system. Image copyright Lucasfilm.
Quantum Entanglement CommunicatorTech Level: 17
LeGuin AnsibleTech level: 17
HyperwaveTech Level: 18
Subspace RadioTech Level: 19
Tachyon CommunicatorTech Level: 21
An ansible, in its most basic definition, is a faster than light communications system, used mostly in the same way radio is used today. It is a central feature in the works of science fiction authors such as Ursula K. LeGuin, but versions of it are also seen in on-screen science fiction such as Star Trek , Star Wars, and others. It usually allows instant or near-instant communication across many light years of distance.
There have been many different suggestions for how ansibles could work. Some are straight forward, usually as an outgrowth of a particular fiction universe’s means of FTL travel. For example, in theStargate universe, Stargates allow two-way radio communication when open, even though matter can only be sent one-way through a wormhole.
FTL communications, like FTL travel, is impossible according to our current understanding of the way the universe works. In all likelihood it will never be a reality unless the laws of physics turn out to be much different from what we currently perceive. And if an ansible does someday become a reality, it raises the unpleasant specter of both time travel and violating causality. However, for this article, such implications will be largely ignored, much as they are in science fiction. Time travel and all its implications will be addressed in a future section dedicated to it.
Because ansibles are mostly pure conjecture with only a tangential connection to real world science, their placement on the Tech Level scale is somewhat arbitrary. Like most FTL tech, the physics behind them is assumed to be discovered at Tech Level 16, with actual applications in the Tech Levels after that in order to coincide with their use by space opera civilizations, where they are most prevalently depicted.
In some science fiction sources, only ansibles will exist and no means of FTL travel will be possible, such as in the first two novels of the Ender series. In others, FTL travel may be possible but ansibles cannot be made to work, such as in the Traveller tabletop RPG. Both can lead to very interesting permutations of stereotypical interstellar civilizations.
QUANTUM ENTANGLEMENT COMMUNICATOR
Tech level: 17
Quantum entanglement is the phenomenon of particles influencing one another’s quantum states even over great distances, seemingly at FTL speeds. The cause is largely unknown, and is one of the admittedly stranger aspects of quantum mechanics. Even Einstein had trouble accepting the reality of it at first, calling it "spooky action at a distance." Much more detailed explanations of it are available in the links at the end of this article.
Current theory as well as experimental data shows that quantum entanglement cannot be used to pass information. However, an FTL exchange of some sort is clearly implied between the entangled particles. It is possible that future generations, with a far more complete knowledge of quantum mechanics than we may have, may discover an unforeseen loophole that will allow them to take advantage of entanglement for communication.
If quantum entanglement communicators do become possible, they would have no range limits. One could use such a communication system to talk to someone in another galaxy as easily as someone the next street over.
However, the communication would only be possible between devices that had their particles entangled beforehand. In other words, one would have to start out with a base population of particles in one place, and farm them out to the communicators that will be in the network. Communication can only work between these ‘mated’ devices and no others. For better or ill, no other devices can ever ‘listen in’ on the communication network, even other quantum entanglement sets, unless they have some of the previously-entangled particles.
The communicators will also only have one open "channel" between all the sets in a network. There’s no such thing as switching frequencies with this type of communicator.
Quantum entanglement communicators have appeared in several science fiction stories by Stephen Baxter.
LEGUIN ANSIBLE
Tech Level: 17
The ansible in LeGuin’s works seem thematically similar quantum entanglement communicators, but instead depended on the principle of "simultaneity." Simultaneity in classic physics refers to different events happening at the same time. However, The theory of relativity shows that in the real world simultaneity is also relative; events that seem simultaneous in one frame can seem to occur at different times in another.
LeGuin’s ansible seems to contradict this and instead relies on some unknown universal reference frame where absolute simultaneity can be upheld. Sending and receiving units were ‘entangled’ somehow so that when something happened to one, it simultaneously happened to the other When one communicator is manipulated, the same message typed into it appears on its mate many light years away. This could be quantum entanglement at work, or perhaps its made possible through the use of a higher physical dimension like hyperspace as a universal reference frame.
LeGuin ansibles needed at least one communicating device located within a gravity well of planet, and the other away from one, located almost anywhere out in space. These ansibles didn’t have exclusive ‘mates’ as with a quantum entanglement communicator. One can be tuned to any other ansible, as long as its coordinates were known.
HYPERWAVE
Tech Level: 18
Hyperwaves are also sometimes called Ultrawaves, and mostly come from stories and novels by Isaac Asimov, such as the Foundation Trilogy. The exact inner workings of these devices was usually left conveniently obscure, but the implication was clear that they were related to the same operating principles of the hyperdrive. Other sources that have both hyperdrives and FTL communications (such as Star Wars) probably have similarly related technologies.
In practice, hyperwaves behave, and are mostly used, exactly like mundane radio and television communication sets. They seem to work instantaneously, work in multiple channels and frequencies, can be widely broadcast and picked up by anyone else with a hyperwave device.
The principle that hyperdrives work on is that the ship bypasses the distances of our three-dimensional space by launching itself into a higher physical dimension, or "hyperspace." This hyperspace is not another universe as is often thought, but rather simply another aspect of our own universe that we 3D creatures don’t often have truck with. If its relationship with the ‘lower’ dimensions of our universe align in the right ways, travel through this fourth physical dimension can be much shorter than traversing 3D space exclusively.
A good analogy is surface travel on a globe. Rather than travel over the 2D surface to get to the other side of the globe, a traveler instead goes right through center of the sphere, taking advantage of a higher physical dimension--in this case, the third--in order to shorten his trip. Travel through hyperspace is conceptually similar, only taken up a dimensional step.
If physical objects can pass through hyperspace, there’s little reason to assume radio waves couldn’t do so as well. Hyperspace is just another aspect of our own space/time, and all the physical laws that apply to our familiar 3D surroundings would apply equally in the 4D realm as well.
A hyperwave, therefore, may simply be a small, self-contained hyperdrive unit that opens an aperture into hyperspace just large enough to allow a radio signal to be broadcast through that realm, or to receive such a broadcast in turn. How exactly this is done would depend on how the hyperdrive physics worked in that universe. Like with a hyperdrive, the radio broadcast may need to be locked onto a specific hyperspatial trajectory at the time of transmission in order to be received at the desired destination. In this case, it can only be ‘beamed’ at one destination at a time.
Because it is only sending a radio signal instead of a multi-ton starship into hyperspace, its assumed hyperwave units need much less energy to operate than standard hyperdrives. Hence, why hyperwave units are usually depicted as smaller and more portable than their ship-moving cousins. Also, this implies that hyperdrives could be turned into hyperwave radios with some modification.
Hyperspace may not just be an empty void, however. It may have phenomena that may block, interfere, or distort a hyperwave signal much in the same way that three-dimensional space does.
SUBSPACE RADIO
Tech Level: 19
Subspace radio is the main means of FTL communication in the Star Trek universe.
Subspace is an odd concept, that is used (some would say overused) to explain away a lot of the odd anomalies and FTL physics in the various Star Trek series. It is not a separate plane of existence, nor is it a hyperspace, exactly. Rather, it is part of the make-up of our own universe with an infinite number of integral levels.
One way to conceptualize subspace is to think of our universe as the number 3. Let's pretend 3 is the very critical number that defines existence, because if the universe added up to even a tiny smidgen less than 3, the whole thing would fall apart and the universe would blink into nothingness. If everything didn't add up to 3, nothing would exist at all.
Subspace would therefore be like all the tiny decimals that exist between zero and three. A layer of subspace would be at 0.5, another would be at 1.4, and still another at 2.9998, etc. All of these numbers must exist for 3 to exist, and if you take away even the smallest of them the whole thing collapses. So think of all these small, fractal, semi-dimensions of subspace being layered and woven together intricately to form our universe. Some of these subspace fractal dimensions are intricately tied into our everyday existence (such as the ones that determine known physical laws), other may exist only tangentially to our common experience of reality (such as the subspace layers used in Star Trek to allow FTL travel), still others may have collapsed into the planck-scale level of the universe and may manifest themselves only in certain circumstances (such as some of the "spatial anamolies" found in the various Star Trek series.)
Subspace communications would use designated layers of subspace, such as those that allow FTL travel, in order to propagate radio and other signals at superluminal speeds similarly to a hyperwave. Alternately, it may manipulate these layers directly in some way in order to create a superluminal phenomenon that can convey information. In the latter case, different "channels" may simply mean switching the signal to a different layer of subspace.
The Federation and other civilizations of the Star Trek universe use a network of subspace relays to amplify and rebroadcast subspace communications throughout their territory. Within the network, communication can be accomplished in real-time even across the breadth of hundreds of light-years. Without these relays, however, communications even at FTL speeds could take weeks or even years to reach the intended party, depending on distance and conditions.
TACHYON COMMUNICATIONS
Tech Level: 21
Current theory spells out explicitly that nothing material can ever be accelerated to the speed of light, much less beyond it. But what if a particle came into existence that was already moving faster than lightspeed ? Since it was never accelerated from a lower velocity, it does not violate relativity. This type of purely-theoretical particle is known as a tachyon.
Tachyons are a theory that goes back decades, and have never been shown to exist in the real word. But if they were proven a reality, they would have a number of very unusual properties. Tachyons would forever exist on the other side of the lightspeed barrier in a strange mirror to our own universe. At their lowest energy levels they would have literally infinite speed, and as they gain energy, they slow down. The slowest a tachyon can ever go is the speed of light, but for that it would need nigh-infinite energy. Even more oddly, their arrow of time is the opposite of ours. They can only ever travel backward in time. More complete explanations of tachyons and tachyon theory are discussed in the links at the end of this article.
It is thought that very high energy collisions, such as those produced by cosmic rays high in the atmosphere, can produce tachyons. If this bears out, these conditions could eventually be reproduced in particle accelerators to give future physicists a source of the particles to work with. A tachyon burst could then be aimed in the direction of the receiving target and broadcast much like a directed radio beam.
However, unlike the other ansible schemes outlined here, the prospect of time travel is much harder to ignore with tachyons. By their very nature, tachyons must travel backward in time, and this causes many potential paradoxes and causality violations. If you use a tachyon communicator, your message will always be received before you even send it.
How far into the past it goes may be relative, however, and risk factors can be minimized. If low-energy tachyons have nigh-infinite speed, they can reach anywhere in the universe in a fraction of a second. For example, the receiver a galaxy away may get your signal in .0000000004 seconds before you send it, such a tiny span of time that it may pose no significant consequences to the causality in either frame of reference on a macroscopic scale. Its with the higher-energy signals, using more pumped up, slower moving tachyons, that paradoxes and other causality problems may pop up.
Because of the need to stick to low-energy signals for tachyon communications to avoid the worst of the potential paradoxes, much more sophisticated technology is needed to detect the comparatively weak signals. Hence why Tachyon Communications has a much higher tech level than the other ansible schemes outlined here.

HYPERDRIVES

A Vorlon Mothership opens a portal to hyperspace in the Babylon 5 Universe. Image copyright PTN Consortium and Warner Bros.
Transfer Point HyperdriveTech Level: 16
Standard HyperdriveTech level: 17
Multiple Level HyperdriveTech Level: 19
Made popular by a number of SF sources, this drive postulates temporarily shunting a starship into a higher dimensional space that also permeates our own universe. This other space has different physical topologies than our own, and distance, even light-years of distance, means something very different there. The ship can traverse the equivalent of quadrillions of kilometers in a relatively short time, so that the stars are easily bypassed when the ship re-enters normal space.
HYPERSPACES
The word "hyperdrive" takes its name from the term hyperspace. Hyperspace is the theoretical realm that exists beyond our three-dimensional world, which permeates our universe and into which our space/time can curve.
Links to much more detailed explanations of hyperspace are given at the bottom of the page. What follows is an extremely simplified discussion.
Take a one dimensional object, a line. Turn the line in on itself at right angles and you get a two dimensional object--a square. Now take the square, turned it on itself at right angles, and we go up a dimension to the third. A cube.
Now take the cube, turn it on itself at right angles and you get...
What?
According to theory, you get an object that projects into a fourth physical dimension (not to be confused with Time, which is also sometimes called the fourth dimension) called a hypercube. Trying to actually visualize this with our analog 3D brains is a bit difficult; however, the mathematics and logic of it work out very neatly, and leads to a number of interesting implications.
Think of a 2D object, like an infinitely thin piece of paper. You can "warp" it into a third dimension by folding or rolling it. We know from Einstein that 3D space can also be warped; observational evidence for this abounds in the form of gravitational lensing effects in astronomical objects. But what does it warp into?
The answer is hyperspace. A fourth physical dimension somewhat beyond our three-dimensional senses to perceive, but which surrounds and permeates our 3D universe much like the 3D universe surrounds and permeates our 2D piece of paper.
But how does this help one travel between the stars?
There is some evidence that our 3D cosmos as a whole may be curved, just as a 2D object as a whole can be curved into a sphere or parabola or such. Instead of travelling the entire distance over the curved surface of the 2D object, one can simply bore a tunnel between two points on the paper through 3D space to arrive at your destination that much sooner.
The hyperdrive uses this principle taken up a dimensional level; it allows a ship to take a more direct 4D "shortcut" to bypass the 3D "surface area" in between two points.
However, it should be pointed out that just because such hyperspaces may exist they may not necessarily allow FTL travel, or indeed allow any kind of travel faster than what’s available to us in normal 3D space. Three-dimensional space may not be curved in the right way to allow any significant shortcuts; hyperspace itself may be curved and complicated in many ways that would make accessing it problematic if not impossible.
For instance, if our 3D space has no macroscopic curve (a "flat" universe in some terminologies) hyperspace access could turn out to be fairly useless as a means of FTL travel.
The best example of this, ironically, comes from a SF universe better known for a very different means of FTL travel: Star Trek. The warp drives of the civilizations in Star Trek double easily as hyperdrives, and, indeed, can be seen on many episodes and movies moving in and out of hyperspace with ease. However, in that universe, no hyperspace or level thereof has apparently been found that allows for travel faster than warp 1. Thus, the Federation and its neighbors still rely exclusively on the warp drive for interstellar travel, and apparently use hyperspace simply to avoid material obstacles such as gravity wells, hydrogen clouds, etc, that they may otherwise run into at translight speeds in normal space.
Hyperspace is also almost certain to be far more complicated than just a void with an extra physical dimension. It may be prone to odd curvatures and anomalies, may be host to different storms, currents, hyperobjects, and perhaps even life. This is the case in Jeffrey Carver’s Star Rigger series of novels, as pilots ("riggers") translate the chaotic dangers of hyperspace into visual metaphors they can more easily grasp, and literally have to "sail" through hyperdimensional storms, whirlpools, tidal waves, and other dangers.
Hyperdrive travel can also be complicated by the fact that more than one level of hyper space can exist. After all, if there’s a fourth dimensional aspect to the cosmos, why not a fifth or sixth or so on? Each level may be subject to physical quirks we can only guess at, and would have its own dangers and advantages. Even if 3D space is flat, the 4D space that permeates it may itself be curved, allowing ships that can access the 5D "level" of hyperspace FTL travel where a lower level 4D hyperdrive would get the pilot nowhere. It is generally assumed that accessing higher levels of hyperspace require more powerful and sophisticated drives that lower levels do.
This can even be further complicated by the possible existence of fractal dimensions. A fractal dimension exists between two "integer" dimensions and contains aspects of both. Often, mathematical and physical constants will vary slightly from one fractal hyperspace to another. For example, it could be possible to define a fractal dimension by its particular value of pi. One level would have a pi value of 3.14159..., one would have a pi value of 4.78, and another would have a value of 3.00 exactly. As with decimals, there would be an infinite number of fractals between integer dimensions, and therefore an infinite number of possible hyperspaces.
Of course, the hyperspace level with a value of pi of 3.14159... not coincidentally corresponds with our own universe’s value of pi, indicating that in this cosmological scheme our universe is just yet another a level of hyperspace. Every other level would also be a universe in and of itself.
ACCESSING HYPERSPACE
In order to a enter higher dimensions, one has to warp 3D space. As natural-occurring gravity sources readily warp space, most hyperdrive schemes envision artificial, concentrated gravity fields to warp or tear or weaken the fabric of space/time in order to insert the ship into higher-dimensional space. These may be enhanced or complimented by other quantum mechanical tricks left conveniently obscure by science fiction creators.
In several versions of the hyperdrive, the drive imparts a higher dimensional "momentum" to the starship, meaning the ship can’t alter course or come out of hyperspace until it comes to the end of its 4D trajectory and ends up precipitating back into normal space. This is the case of the hyperdrives in Asimov’s Foundation series, the world of the Traveller RPG, and the Star WarsUniverse.
In other versions, the hyperdrive opens a "portal" or undergoes a phase shift to enter hyperspace, and the ship can maneuver around freely in the higher dimensional realm. The ship has to open another "portal" or phase shift again to exit it. This is similar to the scheme used in Babylon 5and the "Known Space" stories of Larry Niven.
EXPERIENCING HYPERSPACE
Exactly how hyperspace would be perceived by our 3-D brains and perceptions is a matter of much wild speculation in SF sources. There’s no way we can know for sure until (and IF) a real hyperdrive is ever made. Still, some authors have come up with some very interesting conjectures. For example...
In Asimov’s Foundation series, there is no hyperspace experience, because the transition to 4D and back again takes place nearly instantaneously.
In the universe of the Fading Suns, the hyperjump temporarily alters human brain chemistry and induces a mystical, near-ecstatic experience on many passengers. The phenomenon became the basis of a popular and influential religion in that universe.
In the universe of the Traveller RPG, many passenger can experience jump sickness--the transition to hyperspace stresses the space/time within the ship, resulting in possible vertigo, nausea, and spasms that can last anywhere from a few minutes to the entire time the ship spends within hyperspace.
In Larry Niven’s "Known Space" stories, hyperspace literally has nothing we can perceive--not time, not space, not even a void. As a result, windows on a starship experience a phenomenon called the Blind Spot, where--with absolute NOTHING beyond the porthole--the brain "stretches" the images of the surrounding bulkhead so that it covers the hole in its perception, just like it does its natural blind spot. The window and every other portal that opens into hyperspace disappears from visual human perception. Passengers have been known to go mad staring at the Blind Spot for too long.
Some versions of hyperspace envision it as having truly bizarre physical laws that sometimes contradict those of our 3D universe, necessitating a protective bubble of "normal" spacetime be wrapped around the ship to protect it. However, as the 4D+ cosmos would just be a natural extension of our own, all natural laws of our universe would still apply, and no special protection would in fact be necessary.

TRANSFER POINT HYPERDRIVE
Tech Level: 16
This is similar to the standard hyperdrive, but in this scheme hyperspace can only be accessed at certain points where hyperspace and normal space overlap. Hyperdrives simply won't work unless they are at these coordinates. The ship will enter one transfer point and come out another. Usually, a transfer point will only lead to a few destinations, and sometimes to only one. Webs of transfer points would cover the galaxy, as the ship would have to go from one transfer point to another to the next and so on to eventually arrive at its destination.
The position and abundance of transfer points depend on how they would form. For example, in the novel The Mote in God's Eye, by Niven and Pournelle, transfer points were formed between two stars at the point where their gravitational fields were most synchronous, forming low energy "channels" through four dimensional space-time. In other universes, the tides and eddies of hyperspace itself may determine when and where transfer points form. In the latter case, transfer points may constantly shift position throughout space, creating all sorts of chaos for interstellar civilizations. Transfer points may only exist in a system for a short time, severely limiting interstellar contact for only a few days or weeks every decade or so. Being able to predict where transfer points will appear and how long they will last would be necessary for any FTL civilization to thrive in such a universe. Passage through transfer points are generally depicted as instantaneous or nearly so. However, travel between transfer points in the same system in normal space may take days or weeks or months, depending on the type of sublight drive available.

STANDARD HYPERDRIVE
Tech Level: 17
The Millennium Falcon enters hyperspace in the movie Star Wars. Image copyright Lucasfilm.

A standard hyperdrive uses gravity manipulation and/or quantum effects to warp the fabric of the universe around it in order to launch itself into hyperspace. Usually a standard hyperdrive can only access one level of hyperspace per jump. I.e., it enters that level of hyperspace and can’t exit it again until it precipitates back into normal space.
Though a hyperdrive can access hyperspace from theoretically anywhere in space, some conditions and areas may make the feat more dangerous or difficult than others. In the Traveller and Known Spaceuniverses, hyperdrives are dangerous to operate too close to significant concentrations of mass, such as a star or planet. In Traveller, a star ship must be at least 100 diameters out from a planet or star to make a safe hyperjump; in Known Space the ship must be on the extreme borderlands of a star system for its hyperdrive to function.
In other schemes, the opposite is true. In Ursula K. LeGuin’s Ekumen stories and Karl Schroeder’s novel Permanence, a ship had to be deep in a gravity well in order to get the extreme space curvature needed to enter hyperspace.
MULTIPLE LEVEL HYPERDRIVE
Tech Level: 19
A ‘standard’ hyperdrive is able to access only one level of hyperspace per jump. This is because its systems are designed to bend, ripple and/or stretch only standard three-dimensional space, and therefore can enter and exit any one level of hyperspace from 3D space only.
A multiple level hyperdrive uses an advanced version of the same gravity/quantum manipulation effects that bend and stretch 3D space to further warp and bend higher dimensional spaces in an analogous way, allowing the ship to "climb" up and down hyperspacial levels at will. In universes where different levels might have differing features, such as one level allowing faster absolute travel or another possessing less turbulence or obstacles, the advantage of being able to switch levels easily should be obvious.

INTERDIMENSIONAL DRIVE

Standard Interdimensional DriveTech Level: 19
Shielded Interdimensional DriveTech Level: 21
Interdimensional drives are often confused with hyperdrives, and many science fiction sources freely mix and match their features. They do use similar principles--shunting the ship into a universe other than the one we’re familiar with to bypass huge distances--but in truth are distinctly different. (Note: The TV series Earth: Final Conflict employed a means of FTL travel called an interdimensional drive, but that worked very differently from what’s described here.)
STANDARD INTERDIMENSIONAL DRIVE
Tech Level: 19
Interdimensional drives work on the principle that our universe is not unique. That there is, in fact, an infinite number of universes that exist alongside our own, created simultaneously with our own Big Bang, a mere quantum vibration or Planck-scale right turn away. Anyone familiar with the concept of alternate realities or divergent histories or with Everett’s "Many Worlds" interpretation of quantum physics is probably already conversant with the idea. The TV seriesSliders and the "mirror universe" episodes of different Star Trek series are probably the best known examples of this concept in science fiction.
How exactly one could access these "parallel" realities, if they exist, is a matter of some debate. As with many other FTL schemes, the means required would depend much more on the nature of the universe (or multiverse, in this case) turning out a certain way than on just raw technical sophistication. Most "other" dimensions are considered to be separated from ours by some group of quantum properties unique them, such as different "vibrational" Planck-scale wavelengths or electron spin resonance or some such. Therefore, accessing these other realities would depend on the warping of space by gravity manipulation or the use of advanced quantum-force manipulation or a combination thereof. The most common motif, popularized by Sliders and other recent SF sources, is the use of a wormhole to open an actual doorway into other dimensions.
However, the topologies of the many various realities are not necessarily in synch. Three-dimensional coordinates in one universe does not necessarily correspond with those of one right next door. In other words, if you were on Earth when you shifted realities, you would not necessarily end up on the same spot on the Earth in the new universe--you may end up in the middle of the ocean, in orbit, on Mars, or even halfway across the cosmos. It would all depend on how the four-dimensional curvature of the originating universe lined up with that of the target universe.
So, basically, by using interdimensional travel, one could theoretically enter another universe, take three steps to the right, re-enter our universe, and end up galaxies away.
Of course, not all alternate cosmos would necessarily have the properties to be conducive to this sort of travel, and those that are would need to be mapped for entrance and exit junction points that offer the fastest and best travel. Worse yet, the coordinates may not remain in static correspondence--their relationship may shift over time, so that a route that led to another galaxy one time may lead only to the closet down the hall the next.
Also, there is the problem that temporally the universes may not line up in synch either, meaning that transitioning briefly to another universe may shift you moments, or centuries, or eons into your past or future as you re-enter your home reality.
These drives provide the ship with no particular protection against interdimensional physical property changes; the ship is completely subject to the physical laws of the newly-entered universe, whether they be friendly or hostile to the ship’s well being. Usually, when employing these "naked" ID drives, a ship must by necessity only enter universes with physical laws are close if not identical to its own, or risk all kind of unpleasant consequences.
SHIELDED INTERDIMENSIONAL DRIVE
Tech Level: 21
Another hazard with using interdimensional travel as an FTL option is that not all universes will end up having the same physical laws. When a ship enters a new reality, it becomes a part of that reality and is subject to its physical laws. This is good in some ways, as one universe’s properties may result in the compression of space or greatly expanded values of lightspeed or some such, meaning that even in a straight coordinate-to-coordinate match between two universes a ship can still use the "new" universe to cheat the lightspeed limitations in its "old" universe.
However, even a small change in many physical laws would result in delicate and complex biological systems--like the human body--to go haywire or stop functioning altogether. Our lives literally depend on many universal values to remain exactly he same from one moment to the next. Slightly lower physical constants of friction, for example, would have the heart pump blood at hundreds of miles an hour into the bloodstream; shifts in the value of the amount of charge an electron can carry would result in our nervous system frying itself; a decrease in how strong the Van Der Walls forces, the forces that hold molecules together, could result in crewmen being vibrated into puddles of monomolecular goo just by the force of inhaling a breath. And so on and so forth.
In order to avoid this hazard, one solution is for the ship to "carry" a bubble of its own universe with it, to act as a buffer or shield against the ravages of the physical oddities of its transitional reality. Just before it enters a new universe, the ship "folds" a bubble of its originating universe around itself, where its old physical laws still apply. This is in fact very similar to the warp bubbles used in Warp Drives, but instead of facilitating travel the bubble is used to preserve the ship against hostile physical universes.
Just how stable this bubble of "normalcy" would be is unknown. It might be very stoic, lasting without a scratch for as long as needed, or it might slowly wear away or degrade the longer the ship is in the hostile universe, dictating the length of FTL sojourns by how long the bubble can last. Having the bubble seriously degrade would be a terrifying experience for those aboard an Interdimensional Drive ship, because it wouldn’t just "pop" or physically wear down such like a normal bubble. Rather, the physical laws of the new universe would simply, inexorably, begin asserting themselves and the bodies of the crew and their ship around them would slowly begin to break down...
The "hyperdrive" of the Traveller RPG universe acts very similarly to an Interdimensional Drive, including the use of a "normalcy bubbles" (called "jump bubbles" in the game) to protect hyperdrive ships from the hostile physical laws of its hyperspaces.

WARP DRIVES

A diagram of the Alcubierre Warp Drive.
Alcubierre Warp Drive
Tech Level: 19
Star Trek Warp Drive
Tech Level: 21
Warped Space Corridor
Tech Level: 24
Instead of shunting the ship into a higher-dimensional continuum like hyperdrives, warp drives instead bend the space-time of our own universe around the ship. This creates a region of subjective space-time that is out of synch with the rest of the universe. Einstein's Theory of Relativity clearly demonstrates that no physical object can travel faster than light. However, how fast spacetime itself can move in relation to itself is unknown, and can theoretically be moved at any speed. Because it is "detached" from normal space, a region of warped spacetime--including any ship within it--can be moved faster than light.
Like with most other FTL schemes, how exactly to achieve this extreme warping of the fabric of space remains conveniently obscure in most science fiction sources. Engineering powerful artificial gravity sources as well as expert manipulation of quantum effects seems to be implied in Star Trek. In Alcubierre's scheme, the ability to harness and manipulate large amounts of negative energy--still a very theoretical notion--would be necessary.
ALCUBIERRE WARP DRIVE
Tech Level: 19
In 1994, Miguel Alcubierre, a physicist at the University of Wales, described a means of space travel that bore an remarkable resemblance to the warp drive of science fiction.
In his paper published in the May 1994 issue of Classical and Quantum Gravity, Alcubierre described using large amounts of negative energy to create distortions of space/time around a spaceship. In front of the ship, the fabric of space is compressed, contracting the distance between the ship and its destination. In back of the ship, the fabric of space is expanded, increasing the distance between the ship and its point of departure. These distortions move along with the ship, creating a "wave", as some have described it, of distorted spacetime that the ship rides to its target. Because it is space/time itself which is moving and not any physical object within the "wave", this motion does not violate Relativity, even though to an observer outside it would very much appear that the ship was moving at FTL speeds.
Another way to think of Warp Drive movement is to visualize space as a stretched sheet of rubber, and the section of "normal" spacetime between the two extreme distortions created by the Alcubierre drive (referred to sometimes as a warp "bubble") as a marble resting on its surface. Instead of moving the marble directly, you push into the rubber sheet with your finger directly in front of the marble, while someone your finger on your other hand pushes up on the rubber directly behind the marble. By moving your fingers at a fast enough rate, you can move the marble all the way across the sheet, by creating a constantly-moving "warp" in the rubber the marble is continually trying to fall into. Extend this analogy into four-dimensional space and you have the basis for the Alcubierre warp drive.

STAR TREK WARP DRIVE
Tech Level: 21
The starship Enterprise activates its warp engines. Image (c) Paramount

No discussion of warp drives can be complete without an examination of Star Trek's famous fictional engines. Though the "official" explanation for just how the Federation's ships zoom around space has changed over the course of the franchise (and with over 700 hours of on-screen stories spread across 40 years to keep track of, consistency can be understandably dicey), we will explore the most likely explanation for it.
When Star Trek was originally conceived, the warp drives were simply explained as being able to warp space/time in some mysterious way as to allow faster than light travel. Like with Star Wars' Hyperdrive, they mostly travelled at the speed of exposition--they always took as much or as little time to reach their destination as the script demanded.
However, during Star Trek: The Next Generation and throughout most of Star Trek: Deep Space Nine, the series creators seemed to get much more serious about warp theory, introducing the idea of warping subspace.
Subspace can be a difficult concept to understand. It is NOT a different dimension or a different universe or even a different "level" of our own universe--not exactly. From what I was given to understand watching the series and from various online sources, subspace is instead the strata of our own space/time, intricately interwoven to form the structure of our reality.
One way to conceptualize subspace is to think of our universe as the number 3. Let's pretend 3 is the very critical number that defines existence, because if the universe added up to even a tiny smidgen less than 3, the whole thing would fall apart and the universe would blink into nothingness. If everything didn't add up to 3, nothing would exist at all.
Subspace would therefore be like all the tiny decimals that exist between zero and three. A layer of subspace would be at 0.5, another would be at 1.4, and still another at 2.9998, etc. All of these numbers must exist for 3 to exist, and if you take away even the smallest of them the whole thing collapses. So think of all these small, fractal, semi-dimensions of subspace being layered and woven together intricately to form our universe. Some of these subspace fractal dimensions are intricately woven into our everyday existence (such as the ones that determine known physical laws), other may exist only tangentially to our common experience of reality (such as the subspace layers used in Star Trek to allow FTL travel), still others may have collapsed into the planck-scale level of the universe and may manifest themselves only in certain circumstances (such as some of the "spatial anamolies" found in the various Star Trek series.)
The Star Trek warp drive does not brutally manhandle the whole fabric of space/time like the Alcubierre drive, it subtly manipulates select layers of subspace--substrata of our own universe--like a musician deftly plucking the strings of a violin. Like the Alcubierre version, the Star Trekwarp drive stretches and compresses the fabric of space/time, but does it only to those layers that most relate to its rate of travel. Using the stretched sheet of rubber analogy above, it would be like only stretching the topmost layers of rubber to move the marble (the warp bubble) rather than distorting the entire thickness of the sheet.
Different subspace layers would affect and/or make up the physical constants of our universe, so by warping these layers the engines could theoretically alter the local limit of lightspeed or the relative inertia of the ship. Finding these layers and learning to manipulate them subtly enough to allow superluminal speeds but not to screw up the physical laws that keep our bodies and technology functioning would require a great deal of technical sophistication, hence the Star Trek Warp Drive’s very high Tech Level compared to most other ship-dependent FTL schemes.
The area of warped space/time around the Federations’ ships are two-lobed, explained in the official material that the differing "subspace pressures" between the front and back lobes drive the ship forward. In practice, these would probably just be subspace versions of the contracted/expanded spacetime that drive Alcubierre’s version of the concept.
WARPED SPACE CORRIDORS
Tech Level: 24
An idea that occassionally manifests itself along with discussions of Alcubierre’s warp drive. Instead of just temporarily warping spacetime around a moving ship, a highly advanced civilization will permanently alter the space in between two points to allow faster travel. These warp "highways" would resemble broad corridors between star systems, wherein the spacetime would be altered in such a way as to allow FTL travel, at least relative to the universe outside the corridor.
However, within the corridor, spacetime is either compressed so as to shorten the distance between the two points, or the speed of light is greatly elevated to allow much greater velocities to be achieved. No special engine is needed to utilize the corridors--any sublight engine would suffice, as the FTL properties would be contained in the corridor itself, independent of the ship.
Warp corridors would be very much unlike wormholes, in that the ship can enter and exit the corridor at anytime with no harm, whereas a wormhole must be entered and exited only at its mouths.
Undertaking such an immense and exotic engineering project would require a near mind-boggling level of technical sophistication, as it would require an insane amount of negative energy to create interstellar conduits of warped space light years long. And of course advanced civilizations would more than likely build huge webs of such corridors throughout their region of space.
How stable such corridors would be is unknown. They would likely degrade over time and need constant upkeep similar to normal highways.

WORMHOLES

"A Wormhole in Time Square." Image originally appeared in and copyright to Scientific American magazine. Original Photoshop artist unknown.
Kerr-Newman RingwarpTech Level: 23
Standard WormholeTech Level: 23
Visser WormholeTech Level: 25
Wormholes are more properly called Einstein-Rosen Bridges, after the two men whose work in the early 20th century led to the first theories involving the extreme warping of space. However, the theory was considered too fantastic to be taken seriously at the time and was little more than an aberrant curiosity for decades. Then, in the 1980s, physicist Kip Thorne, trying to help his pal Carl Sagan create a believable means of interstellar travel for the novel Contact, looked hard at the old equations and, with the help of graduate students Michael Morris and Ulvi Yurtsever, found that wormholes perhaps weren’t that far-fetched after all. In the years since, the theoretical study of wormholes has been expanded considerably by a number of leading physicists.
The actual physics behind wormhole formation are incredibly complex; in order to save on space and the readers’ sanity, only extremely simplified versions are presented here. Links and references to more complete and technical works on the subject are provided at the end of this article.
In their simplest definition, wormholes are four-dimensional tunnels bored through the fabric of space-time itself. They can be created by warping space with very unlikely tools--either with singularities, which lie at the heart of those fear-inducing objects called black holes, or by tapping into the basic, planck-scale firmament of the universe itself.
A black hole is a spherical area in space that absorbs all light, energy, and matter that encounters it; a singularity is a pinpoint of super-collapsed matter, the remnant of a massive dead star, that lies at a black hole’s center. The singularity has infinite density and no physical dimensions--no length, no width, no height. It is quite literally an infinitesimally tiny point with the mass of an entire star packed into it. Its gravity field is so immense that its escape velocity exceeds lightspeed--hence its radius of utter darkness as seen from the outside. This gravity field also warps space to such a degree that physical laws as we know them break down.
But a sufficiently advanced species could also use this warping of space to their own benefit, to drill shortcuts through the fabric of the universe to reach across the cosmos.
Despite what has been depicted in a number of sci-fi sources, naturally-occurring black holes donot give birth to wormholes--at least, wormholes that a spaceship could survive passage through. These wormholes form only at the birth of certain rare singularities, go nowhere except to space-time dead ends, and last only microseconds. Any ship unlucky enough to be caught in one would be crushed instantly by the immense gravitational forces crashing in on them as the wormhole collapsed, if it could survive passage that close to a black hole to begin with.
KERR-NEWMAN RINGWARP
Tech Level: 23
Black holes are not all alike; they come in a number of different varieties. It is only the artificial combination of very specific black hole characteristics that can give birth to a type of traversible wormhole called a Kerr-Newman Ringwarp.
A Kerr-Newman black hole must possess two important factors: a massive electrical charge and a high spin rate. These two factors affect the way the singularity warps space. By manipulating these as the original mass collapses allows the newly-born singularity to punch a hole through the fabric of space. At both ends of the new wormhole will be two black holes with the same singularity at their center.
Because the singularity has no physical dimensions, it does not actually "spin." Rather, the angular momentum oblates the singularity--"flattens" it out--into a ring. The more spin it has, the larger the ring will be. Inside the ring is the tunnel that the singularity has bored through the fabric of space at its creation, pried open. It is possible to expand the ring so its diameter can exceed the black hole’s event horizon, the distance from the singularity at which its escape velocity exceeds light speed. At this point, the event horizon reconfigures itself around the singularity ring, allowing a ship to enter the Ringwarp through its center without being trapped by the black hole’s gravity. And thus a traversible wormhole is born.
Expanding the ring diameter is tricky at best once the ringwarp is formed, so the best means of ensuring a large wormhole opening is piling on the angular momentum as the black hole is formed. Spinning the target mass to near lightspeed as it collapses is the best way. Extremely advanced and powerful gravity manipulation would also help. The ringwarp mouth can also be held open or expanded with generous amounts of negative energy, as explained below.
Instead of creating a tunnel to another portion of our universe, a Kerr-Newman Ringwarp can be used to punch a hole into hyperspace. It is possible ringwarps could all open into the same hyperspace, allowing the creation of "hypergates." The ship would enter one Kerr-Newman Ringwarp, travel through hyperspace, and exit through another Ringwarp in another star system. However, its also as likely that all ringwarps open into their own hyperspatial dead-ends, and can’t be used for FTL travel this way.
A civilization that had to depend on Kerr-Newman Ringwarps for FTL travel would have their work cut out for them. First of all, they would have to sacrifice already-existing masses--planets and stars--to create them. Vast expenditures of energy would be needed to create them (spinning the mass up to near lightspeed, then collapsing it artificially) and to maintain them. They would also be quite delicate--even a relatively small mass (say, that of an average automobile) hitting the star-heavy ring could upset its equilibrium and send the entire wormhole collapsing.
The alien Cheela in the novel Starquake used a Kerr-Newman Ringwarp to save several human astronauts stranded in orbit around a neutron star. In the novel Ring by Stephen Baxter, the alien Xeelee constructed this type of wormhole using cosmic strings, in order to create an "escape hatch" out of the universe.

STANDARD WORMHOLE
Tech Level: 23 Wormhole openings are spherical and show 'reflections' of what's on the farside. Here, we see the distorted image of Earth and the moon from the far side of a wormhole. Artist unknown.

Currently the "common" type of wormhole used by much of modern science fiction, it was first proposed by Michael Morris, Kip Thorne, and Ulvi Yurtsever in a famous paper in 1988. One of the best examples of it, naturally enough, can be found in Carl Sagan’s novel Contact. A wormhole was a central feature of the TV series Star Trek: Deep Space Nine. In the novel the Ring of Charon, by Roger MacBride Allen, an immensely powerful alien species called the Charonians use wormhole technology to steal the planet Earth itself.
One method of accessing wormholes involves not so much creating the tunnels through space/time as mining them from the subatomic quantum foam. According to theory, wormholes are constantly forming and collapsing at the planck-scale level of existence, the point where physical measurements become meaningless, around 10^-33 meters. At this level of existence, space/time is ruled by chaos and is far from stable or "firm," allowing structures like wormholes to form with relative ease.
The vast majority of the wormholes found here lead to only a few planck-lengths away. However, some can stretch many light years, and some may even lead to the other side of the cosmos. We can imagine a species with spectacularly advanced technology might possess the means to detect, stabilize, and expand these otherwise brief-lived quantum wormholes for macroscopic use.
However, expanding the wormhole mouth to usable dimensions and keeping it open takes enormous energies. The gravitational forces at work in the wormhole keeps trying to collapse its openings, requiring some counter-force to keep it open. To think of it another way, the "ocean" of space-time keeps trying to rush in and fill the "drainage" hole created by the wormhole. This creates unbelievable pressure at the wormhole mouth, far exceeding a billion quadrillion tons per square inch for a wormhole with an opening large enough to accommodate most spaceships, say several kilometers wide. This level of pressure is akin to having millions of earth-sized planets balanced on your thumb.
This problem of pressure can be counteracted in several ways. The first is the use of copious amounts of an as-yet theoretical substance called negative matter. Negative matter would have negative mass and would therefore possesses anti-gravity properties. Negative matter would line the wormhole mouths, counteracting the crushing wave of space-time trying to force its way in. Another way to keep the openings apart would be to use electromagnetic force fields or powerful artificial gravity fields, but keeping the wormhole mouth from collapsing with these methods may require the constant energy output of an entire star. Interstellar species might be forced to build dyson spheres or similar mega-artifacts in order to power their wormholes.
Passage through a wormhole would be as simple as flying through a large spherical chamber or tunnel; a vessel no more advanced than John Glenn’s original Mercury capsule could transit from one star system to the next once the wormhole was built and stabilized. Passage time would be mere minutes at most.
However, wormhole travel has its hazards. Brushing up against the sides of the wormhole throat would mean instant destruction for a ship, as it is shredded and crushed by the immense gravitational forces barely held in check there. Also, too large a mass passing through a wormhole might disrupt the delicate balance keeping it open, causing it to spontaneously collapse. Any ship caught in the mouth of a collapsing wormhole is instantly annihilated. The fate of a ship trapped inside a collapsing wormhole throat is unknown. It might be crushed, it might precipitate out somewhere in normal space, it might be launched into a different universe altogether, or it might be forever trapped in an isolated bubble of space/time with no hope of escape.
There is no limit to how far a wormhole can stretch. A wormhole can span the length of our entire universe as easily as it can the length of a football field. Also, wormholes mouths are not static fixtures; they can be moved. Because they can be electrically charged, a sufficiently powerful fleet of ships can move them using immense magnetic fields. The process would be slow, but one wormhole mouth can be "dragged" in this manner anywhere in the universe while its other opening can stay at its point of origin, allowing its builders to slowly explore the entire universe one far-flung star system at a time.
A Morris-Thorne-Yurtsever Wormhole could also be created from the collapse of matter or energy into a black hole, but this method is assumed to be much more difficult and risky because of the immense energies and forces involved beyond just stabilizing the wormhole. Instead of sacrificing worlds as in the Kerr-Newman scheme, however, a standard wormhole can also be made by creating a kugelblitz--a black hole formed by the collapse of highly concentrated energy as opposed to matter. Basically, if one can pile on enough energy in a small enough space in the right way, a kugelblitz will form, and with it a singularity with the right properties that could be expanded into a wormhole. In the novel Kaleidoscope Century by John Barnes, a small wormhole was formed by specially-tamped, overlapping thermonuclear explosions on the opposite side of the sun from Earth.
Though wormholes are traditionally envisioned as being space-borne objects, its certainly possible for them to be located on the surface of a planet or even on a spaceship. However, unless they’re "locked" in place with electromagnetic or gravitational fields, they will tend to wander as the ship or planet moves about. They are singularities after all, and will still behave like point sources of gravity. On a planet, it is even likely the wormhole would start to orbit the planet’s center of gravity once free of its moorings, completely unmindful of any matter in its way. Assuming it does not instantly collapse, it could plunge up and back through the planet’s crust and mantle on an elliptical orbit around the core, sending megatons of matter through itself every second, leading to catastrophe at both ends. However, this effect can be of beneficial use as well. In the novel Ring by Stephen Baxter, the human civilization used wormholes in this manner to "mine" the interiors of stars.
The usual way wormholes are envisioned in science fiction is as a two-dimensional door. For a Morris-Thorne-Yurtsever wormhole, however, a wormhole mouth would be spherical. You could enter into it in any direction and still come out the other side, which would also have a spherical opening. Remember that wormholes are four-dimensional tunnels with three-dimensional openings, much like a three-dimensional hallway has two-dimensional openings (doorways.) When looking at the wormhole mouth, you would see a spherical "reflection" of what lay on the other side of the wormhole.
Standard wormholes can also be used as time machines. This will be discussed in a future section dealing with time travel.

VISSER WORMHOLE
Tech Level: 25 A cubical Visser wormhole in orbit about Earth. Artist unknown.

An admittedly bizarre idea originally proposed by Matt Visser of Washington University in St. Louis. A Visser wormhole suggests using cosmic strings of negative matter to pry open a wormhole mouth, much like struts of metal or wood can hold open mundane tunnels. The strings would be configured into a cube, with a flat-space wormhole mouth stretched out on each "face" of the cube. The entire cube may be the wormhole mouth, much like a standard wormhole, only cubical in shape instead of spherical. Or each side of the cube may be a different wormhole mouth, each leading to different cubical wormhole mouths at different destinations.
Even if negative matter cosmic strings exist, acquiring them as well as manipulating them into so precise a configuration would require vast technological sophistication beyond what we can easily imagine.

STARGATES

An activated Stargate from the TV series Stargate: SG-1. Image (c) MGM Studios
Alteran StargatesTech Level: 24
Farcaster SystemTech Level: 25
The term "stargate" was first coined by Arthur C. Clarke in his novel 2001: A Space Odyssey, and was at least one function of the mysterious black monoliths found in his seminal novels. Today the concept of stargates are most famously known from the Stargate movie and TV series. Stargate-like systems have also been used in the Hyperion novels by Dan Simmons, the novel A Million Open Doorsby John Barnes, the anime series Iria: Zeiram The Animation, and the science fiction wargameStarcraft, among others.
A stargate is a means of traveling interstellar distances without the need of a spaceship. It is perhaps the ultimate form of interstellar travel. One dials up a destination, steps through the gate, and you end up on another planet light years, or maybe even galaxies, away. Whereas standard wormholes created permanent tunnels through space/time that only have two openings, a stargate system allows the user to travel to any number of destinations from a single departure point.
One aspect all stargate systems seem to have no matter their operating principle is the necessity of both a transmission station and a receiving station, the same device usually acting as both. In many ways stargates superficially resemble closed teleportation systems, only with reaches of interstellar, or even intergalactic, distance. See the article on Teleport Drives for further details.
The availability of stargates to interstellar civilizations would have major implications. Societies where interstellar ships are the predominant form of travel are usually envisioned as networks of separate cultures, like islands connected by boats, or even like towns connected by a highway system. Even though worlds may share common characteristics or heritage, they are still very much separate entities from each other, with their own ideas and traditions.
When other worlds are only a short walk away, however, interstellar civilizations can achieve a level of homogeneity previously impossible. All worlds connected to the stargate network can easily become subsumed into the mainstream interstellar metaculture. This is the case in both the Gua’uld of the Stargate universe and the Hegemony/WorldWeb of the Hyperion universe. A culture trying to resist such assimilation is the main theme in John Barne’s novel A Million Open Doors.
One of the main difficulties after the technology is developed is actually establishing the stargates and the stargate network on the various different worlds of the building civilization, which could number hundreds, thousands, or even millions. This is much more complicated than just building bridges between islands. All destinations are moving targets (planets spin and revolve about their parent stars, which in turn move about the center of the galaxy.) Not only do the multitude of such devices have to be physically built, but a dynamic multi-dimensional coordinate and navigation system would have to be developed for them to remain active. Standard starships would also still be needed to transport or construct stargates at new destinations.

ALTERAN STARGATES
Tech Level: 24
These are the stargates used in the movie Stargate and the TV series Stargate SG-1 and Stargate Atlantis, named after the race in that fictional universe (also known as the "Ancients") who created them. These are the best examples of stargates as the concept exists in the popular imagination.
The Stargate system itself consists of three major components: a potent power source (usually a "naquadah" generator housed underground, but nuclear reactors on Earth are also used), a dialing device (to determine the general destination of the wormhole using a three-dimensional, seven coordinate system), and the wormhole-generating device itself, in this case in the form of a large 30 foot-wide ring.
Alteran Stargates create temporary wormholes between one gate and another. Its assumed that the wormholes created are similar in general to the Standard Wormholes described in the Wormholes article in the FTL section, only access to them is highly "customized" by the machines for practical travel purposes and tactical convenience. For example, a standard wormhole should allow travel both ways through it once established, but the Stargates allow travel only from the activating gate to the receiving gate, blocking any traffic that tries to go back through the other way.
How exactly the gates create these wormholes is never really addressed. There seems to be no loss of matter involved, only the influx of large amounts of energy. Since its specifically stated that the wormholes are created as opposed to mined from quantum foam, one might conclude that they use the energy input into them to create quantum-level kugelblitzes, singularities formed solely by the intense concentration of energy. The gates must also use that same energy input to create the negative energy needed to pry open the kugelblitz singularity to form the wormhole needed. This process would of course be insanely complex and require a very intimate knowledge of space/time topology and quantum mechanics, especially given the relatively low energy levels used to create these wormholes, hence the Stargates’ extremely high Tech Level.
In standard wormhole formation, the wormhole mouth can exist just fine independent of a gate. The receiving stargate may be just there to "guide" the wormhole mouth to the proper destination for travel convenience. Being able to precisely place a wormhole mouth at a moving target in three dimensional space across light-years of distance would be a feat of exact calibration that would be difficult to imagine. Therefore the receiving gate may just function similarly to runway lights for airplanes; it guides the wormhole in from higher-dimensional space to a precise three-dimensional "landing" at its location.
As stated, the Alteran Stargates seem to "customize" travel through the wormholes for various reasons. Besides the one-way feature, the stargates also use "subspace buffers" to make sure only whole objects are transferred through the gate. Any object being pushed through the gate is redirected to one of these buffers, where it is held in temporal suspension until it completely passes through the transfer horizon. Only after that is it sent through the wormhole to the destination gate. An object can still be pulled back out of the gate as long as it has not fully entered one of these buffers. What exactly constitutes subspace here is left extremely vague, and why it would be able to stop the temporal clock of objects entering them is unknown.
In earlier seasons of Stargate SG-1, they likened the stargates in some ways to Star Trek’s transporter, saying that the traveler was "dematerialized" in the subspace buffer and then "reconstructed" once on the other side. However, like with the Enterprise’s original transporter concept, that would mean you would die every time you entered the gate, and an exact copy of you--but not you--would be reconstructed on the other side. The show’s creators have since seemed to downplay that interpretation of the Stargates’ operation, and now vaguely suggest that the object remains whole in the subspace buffer the entire time its held there.
The Warp Gates seen in the science fiction computer game Starcraft seem to be conceptually similar to the Alteran Stargates.
FARCASTER NETWORK
Tech Level: 25
The Farcaster network was one of the essential features of Dan Simmon’s classic Hyperion novels, the first two especially. It takes the concept of a stargate even further. Whereas Alteran Stargates are highly-prized, ultra-tech artifacts coveted and guarded by the owning civilizations, in the Hyperion universe they are so ubiquitous as to be living room conveniences. A number of works, such as John Barnes’ A Million Open Doors and the Anime Iria: Zeiram The Animation use similar from-the-living-room-to-distant-worlds model for stargates, but with not quite the casual ease shown in Dan Simmons’ Hegemony/WorldWeb civilization.
In orbit about each planet of the World Web, a particular kind of quantum singularity would be constructed, one that tapped into the "Void Which Binds" a subspace-like dimensionless void of near-unlimited quantum potential. The exact nature of the Void Which Binds is left vague. In some theories of cosmology, however, its contemplated that the Big Bang may have given birth to many more dimensions that the ones we’re familiar with. Depending on the theory, these "extra" dimensions may number ten or eleven, or even be as many as twenty-six. The reason why we don’t perceive these dimensions is that all but four of them "collapsed" to the planck-scale level of the universe within nanoseconds after the moment of creation. They are still present and still suffuse the cosmos much like our more familiar dimensions of space and time, but are completely inaccessible unless one is able to reach down and manipulate the planck-scale level of existence.
The Void Which Binds may be one of these collapsed dimensions, a quantum realm of no space or time which nevertheless reaches every point in the cosmos past and future.
Once a singularity was constructed, millions of farcaster portals could be potentially constructed on and around the planet, using the rip in space/time provided by the singularity. From what is described in the novel, the singularity seems to create folds in space/time in close proximity to itself at the farcaster portal locations, folds that connect from the planet to destinations light-years distant through the planck-scale non-dimension of the Void Which Binds. The connection apparently remains stable with little maintenance energy needed as long as the portal and the mother singularity remain intact.
Enormous farcaster portals were placed in orbit to facilitate large transport of goods, but large portals were also placed in cities, much like tunnel entrances along a road. Though the portals were usually "locked" on one destination, they could be shifted to other destinations if desired.
On large and affluent worlds, there would be farcaster portals everywhere. Malls would have stores, each on different worlds, with farcaster portals built into the store entrances. The wealthy often had multi-world mansions, with different rooms on different worlds. It was a common occurrence for one or more people in a family to live on one world and commute to work on another through a neighborhood farcaster connection.
The Farcaster system represents manipulating singularities, collapsed dimensional spaces, and folds in the fabric of time and space with extreme precision and miraculous ease, hence its just a smidgen below the god-like technology levels.