Warp drive is a faster-than-light (FTL) propulsion system in the setting of many science fiction works, most notably Star Trek. A spacecraft equipped with a warp drive may travel at velocities greater than that of light by many orders of magnitude, while circumventing the relativistic problem of time dilation. Some of the other fictions in which warp drive technology is featured include: Stars!, EVE Online, StarCraft, Darkspace, Starship Troopers, and Red Dwarf. In contrast to many other fictional FTL technologies, such as a "jump drive" or the Infinite Improbability Drive, the warp drive does not permit instantaneous travel between two points; instead, warp drive technology creates an artificial "bubble" of normal space-time that surrounds the spacecraft (as opposed to entering a separate realm or dimension like hyperspace) - such as the "warp drive" which is used in the Warhammer 40,000 universe. Consequently, spacecraft at warp velocity can continue to interact with objects in normal space.
The idea of warping space as a means of propulsion has enjoyed theoretical study by physicists such as Miguel Alcubierre, who has designed his own hypothetical drive. However, an approach that may be facilitated by our present level of technological advancement has yet to be proposed.
While thought experiments of theoretical physics continue to be formed, no scheme that may allow travel at warp velocity has yet been devised that has also been accepted by mainstream science. Some physicists have proposed a model of FTL travel, formulated in the context of Lorentzian manifolds, which are used in general relativity to construct space-time models.
These models do however show that while it is indeed impossible to exceed the speed of light, in principle it might be possible to circumvent the problem by suitably "warping" spacetime itself. The most renowned theory, known as the Alcubierre drive, uses terminology in accord with Star Trek jargon: "warp factors" measure the warping of space-time, not the magnitude of actual velocity. In his book The Physics of Star Trek, Lawrence Krauss states that while it is possible to actually travel at a velocity greater than that of light via warp drive, huge amounts of negative energy are required to make it work. Gardiner developed a timetable for the development of the warp drive from analyses of history. He concluded the realization of the warp drive might be achieved around the year 2180.
An FTL propulsion system — based on Alcubierre’s warp drive — that utilizes dark energy to propel a spacecraft faster than light has been proposed, and could revolutionize space travel according to an article on the website of Cosmos Magazine. Cosmos Online - Dark energy spacecraft could fly faster than light c The concept is supported by the calculations of several physicists at Baylor University in Waco, Texas. Comparable to the warp drive concept of Star Trek, their theory states that a spacecraft could travel at warp velocity in a bubble of space-time, by manipulating dark energy — the mysterious invisible force allegedly responsible for the observed acceleration in the expansion of the universe. Essentially, the spacecraft would remain in the same place, while space-time ahead of the craft would shrink, expanding again behind it.
At present, there is no known way to naturally or artificially establish a separate, finite space-time region or "bubble" — as mentioned, such a region is necessary to locally suspend or encapsulate the spacecraft within its view of a "normal" space-time. Concurrently, external from that region, there would exist a "warped" space-time, through which the separate region travels at velocities exceeding c, the speed of light.
In 1996, NASA established the Breakthrough Propulsion Physics Program, which sponsored some speculative work on warp drives. After 6 years, this program was discontinued in 2002, with a total investment of $1.2 million. 
The following formula (Einstein field equation), based on general relativity, theoretically permits the travel of an object at a greater velocity than that of light, provided that space-time is curved:
Gμν is the Einstein curvature tensor, which describes the curvature in space, while the constant G without indices is Newton's gravitational constant. Hypothetically, if space-time is warped properly, the velocity of the traveling object does not technically exceed the speed of light, even though they appear to be moving faster than light to observers in normal space-time.
In 2007, physicist Richard Obousy proposed that a warp drive could be created by directly manipulating the extra dimensions of string theory. His idea suggests the expansion of space-time is a consequence of the vacuum ground-state of higher dimensional graviton fluctuations. The vacuum energy equations can be expressed as:
In this model, it is the radius of the extra dimensions that directly controls the expansion of space. Obousy suggests that it is superstrings that wrap around the extra dimensions and thus keeping them compact, but that a sufficiently advanced civilization might influence a string and locally adjust the size of the extra dimension creating a controlled expansion and contraction of the space surrounding an interstellar craft. In July of 2008 it was reported that two Baylor University physicists have outlined how a faster-than-light engine could be created by manipulating the 11th dimension, a special theoretical construct of m-theory.
According to research by Finazzi, Liberati and Barceló the "warp bubble" seems to be unstable.
Warp drive is one of the fundamental features of the Star Trek storyline; in the first pilot episode of Star Trek: The Original Series, "The Cage", it is referred to as a "time warp" drive, and it is stated that the "time barrier" has been broken, allowing a group of stranded interstellar travellers to return to Earth far sooner than would have otherwise been possible.
The episode "Metamorphosis," also from the original series, establishes a backstory for the invention of warp drive, stating that it was invented by Zefram Cochrane. Cochrane is repeatedly referred to afterwards, but the exact details of the first warp trials were not shown until the second Star Trek: The Next Generation movie, Star Trek: First Contact. The movie depicts Cochrane as having invented warp drive on Earth in 2063 (two years after the date speculated by the first edition of the Star Trek Chronology). By using a fusion reactor to heat plasma, and by sending this plasma through warp coils, he created a warp bubble which he could use to move a craft into subspace and hence exceed the speed of light. This successful first trial led directly to first contact with the Vulcans.
The later prequel series Star Trek: Enterprise describes the warp engine technology as a 'Gravimetric Field Displacement Manifold (Commander Tucker's tour, Cold Front), and describes the device as being powered by an anti-matter/matter reaction which powers the two separate nacelles (one on each side of the ship) to create a displacement field (the aforementioned "bubble.") The episode also firmly establishes that many other civilizations had warp drive before humans. Throughout the series, the viewer is made aware that the Vulcans have more advanced warp drive technology than humans even in the 22nd century. Enterprise, set in 2151 onwards, follows the voyages of the first human ship capable of traveling at warp factor 5.2 which under the old warp table formula, is about 140 times the speed of light. In the episode Broken Bow, Capt. Archer equates warp 4.5 as "...Jupiter and back in six minutes."
Plots involving the Enterprise traveling beyond warp 10 were a frequent feature in the original series (such as warp 14.1 in That Which Survives), and for The Next Generation, it was decided that these would no longer be featured. A new warp scale was drawn up, with warp factor 10 set as an unattainable maximum. This is described in some technical manuals as Eugene's Limit, in homage to creator/producer Gene Roddenberry.
The warp factors above warp 10 in the TOS, such as the one above, were slower than warp 10 on the new scale, which reaches an asymptote at warp 10, representing infinite velocity in accordance with the limit imposed by the producers. The Star Trek: Voyager episode "Threshold" concurred with this: the characters ruled that reaching the velocity of warp 10 was impossible — in spite of this, they went on to achieve the velocity, experiencing a peculiar side-effect; they underwent a [reversible] process of hyper-evolution culminating in their transformation into anthropomorphic newts. In this episode, Tom Paris elucidates that, while traveling at warp 10, he was simultaneously present in every part of the universe. At this velocity, the Shuttlecraft Cochrane's sensors are able to collect such enormous amounts of telemetry that the shuttle's storage capacity is completely filled.
The limit of 10 did not entirely stop warp inflation. By the mid-24th century, the Enterprise-D could travel at warp 9.8 at "extreme risk", while normal maximum operating velocity was warp 9.6 and maximum rated cruise was warp 9.2. The Intrepid-class starship Voyager has a maximum sustainable cruising velocity of warp 9.975, the Enterprise-E can go even faster at Warp 9.985. In the alternative future depicted in "All Good Things..." (the final episode of the Star Trek:TNG), Federation starships travel at warp 13.
Warp drive velocity in Star Trek is generally expressed in "warp factor" units, which—according to the Star Trek Technical Manuals—correspond to the magnitude of the warp field. Achieving warp factor 1 is equivalent to breaking the light barrier, while the actual velocity corresponding to higher factors is determined using an ambiguous formula. Several episodes of the original series placed the Enterprise in peril by having it travel at high warp factors; at one point in "That Which Survives" the Enterprise traveled at a warp factor of 14.1. In the Star Trek: The Next Generation episode The Most Toys the crew of Enterprise-D discovers that the android Data may have been stolen while on board another ship, Jovis. At this point the Jovis, which has a maximum warp factor of 3 has had a 23 hour head start which the Enterprise-D figures puts her anywhere within .102 light year radius of her last known position. However, the velocity [in present dimensional units] of any given warp factor is rarely the subject of explicit expression, and travel times for specific interstellar distances are not consistent through the various series.
According to the Star Trek episode writer's guide for The Original Series, warp factors are supposedly converted to multiples of c with the cubic function s(w) = w3c, where w is the warp factor, s(w) is the velocity, and c is the speed of light. Accordingly, "warp 1" is equivalent to the speed of light, "warp 2" is eight times the speed of light, "warp 3" is 27 times the speed of light, et cetera. However, this conflicts with the on-screen usage of the technology, as it would make the Enterprise's velocity insufficient for the voyages depicted in the television series.
For Star Trek: The Next Generation and the subsequent series, Star Trek artist Michael Okuda devised a formula based on the original one but with important differences. For warp 1–9, . In the half-open interval from warp 9 to warp 10, the exponent of w increases toward infinity. Thus, in the Okuda scale, warp velocities approach warp 10 asymptotically. There is no exact formula for this interval because the quoted velocities are based on a hand-drawn curve; what can be said is that at velocities greater than warp 9, the form of the warp function changes because of an increase in the exponent of the warp factor w. Due to the resultant increase in the derivative, even a minor change in the warp factor corresponds to an exponentially larger change in velocity.
Exact velocities were only given in the Voyager episode The 37's where Tom Paris describes Voyager's velocity at warp factor 9.9 (under the new warp table formula) as being about 4 billion miles per second, which would be over 21000 times the speed of light.
The term transwarp has been used a number of times, referring to an advanced form of warp drive used by the Borg. However, the term also refers to a Starfleet development project in Star Trek III: The Search for Spock. Episodes of The Next Generation and Voyager seem to indicate that transwarp technology involves a wormhole conduit directly through subspace as opposed to warping normal space via a manipulation of subspace. However, in the Voyager episode "Distant Origin," a species known as the Voth used a transwarp technology that didn't appear to be similar to Borg transwarp, but rather an enhanced warp technology. It would seem more appropriate, therefore, for the term "transwarp" to refer to any propulsion system that can be considered superior in potential velocity to standard warp drive, without implying any specific technique correlating to this superior velocity.
The USS Excelsior (NX-2000), under command of Captain Styles, was a Federation test-ship for prototype transwarp technology. It is described in Star Trek III as allowing a ship to instantaneously travel at any warp velocity, rather than having to progressively increase velocity to the desired magnitude. Excelsior's first attempt to enter transwarp failed due to sabotage by Chief Engineer Scott of the Enterprise, which prevented the Excelsior from pursuing them.
The bridge readouts of Enterprise-A at the end of Star Trek IV: The Voyage Home (illustrated in the spin-off reference work, Mr. Scott's Guide to the Enterprise published in 1987) suggest that the project ultimately succeeded and the USS Enterprise was indeed fitted with transwarp. Susan Sackett's memoirs attribute the lack of transwarp in Star Trek: The Next Generation to Gene Roddenberry's dislike of the concept.
It is revealed in the episodes "Descent" and "Endgame" that the Borg have discovered the existence of transwarp conduits — regions in subspace that facilitate travel at velocities up to 20 times those of conventional warp drives. These episodes established that the Borg set up networks of these conduits between important areas in the galaxy. Borg transwarp conduits are activated by an encoded tachyon pulse. When a Borg vessel enters a transwarp conduit, it is subject to extreme gravimetric shear; to compensate, the Borg project a structural integrity field ahead of the vessel. Artificial conduits are linked together with transwarp hubs, of which six were known to exist; in "Endgame" one of these hubs, along with the Unicomplex, is destroyed.
Quantum slipstream drive is presumably the standard means of interstellar travel used by Species 116 (of which Arturis was a member) prior to their assimilation by the Borg. In the Voyager episode "Hope and Fear," Seven of Nine remarks that the technology involved is not dissimilar to Borg transwarp technology — her point being that both drives involve the traveling vessel becoming immersed in an alternative plane of space-time rather than warping normal space-time.
This method of travel is also highly similar to the method of superluminal travel used on space ships in Stargate (referenced as "Hyperspace" travel), and Slipstream used in Andromeda (TV series), another space opera created by Gene Rodenberry.
Some years after Star Trek: The Original Series (TOS), Pocket Books came out with a series of publications based upon the Enterprise's encounters during both its first and second five year missions. In "The Wounded Sky" written by Diane Duane, the crew picks up a Hamalki engineer, which invents a new form of the transwarp drive. Even though such books are not considered canon, the theories proposed in the book lend to the ideas of warp and transwarp, and further explain the properties of subspace.
According to the aforementioned book, warp drive does indeed create a bubble of space-time around the ship; however, it is explained that the ship is surrounded by a bubble of subspace — another universe where the speed of light is much faster than in ours; furthermore, the alternate universe is attuned with our own, such that planetary bodies are in exactly the same place, which simplifies navigation — thus the book leans toward the theories of superstring-manipulation, rather than those of warping normal space-time.
The transwarp device invented by the Hamalki uses a different approach to the same idea; in this case, it creates a field around the ship which allows it to enter De Sitter space — a space in which there is infinite energy, zero mass (with exceptions) and no absolute laws of physics. This essentially allows the Enterprise to enter De Sitter space and travel millions of times faster than light. In the narrative, the Enterprise succeeds in reaching the Lesser Magellanic Cloud (200 years away at warp 8), a dwarf galaxy in orbit around the Milky Way Galaxy.
A curious extension of warp travel which has been shown throughout Star Trek is the "Slingshot Effect." First discovered accidentally in "Tomorrow Is Yesterday" (1967), one of the earlier episodes of the original Star Trek series, it is a method of time travel. Whereas the actual procedure is intentionally obscure, it involved traveling at a high warp velocity (depicted in Star Trek IV: The Voyage Home to be over warp 9.8) in the direction of a star, on a precisely calculated "slingshot" path; if successful, the ship is caused to travel to a desired point, past or future. The same technique was used later in the episode "Assignment: Earth" (1968) for historic research — in this episode, the warp factor required for "time warp" is given the name "light speed breakaway factor" — the term "time warp" being established in Star Trek IV. The technique was mentioned as a viable method of time travel in the TNG episode "Time Squared" (1989).
This 'slingshot' effect has been explored in theoretical physics: it is hypothetically possible (though not practical or at all safe) to slingshot oneself 'around' the event horizon of a black hole. The result of such a maneuver would cause time to pass at a faster rate, relative to the ship within the event horizon. Such a journey would, unfortunately, be a 'one-way' trip into the future — the pilot of the craft would not have 'traveled through time' in the classical sense, but would instead have merely 'skipped over' the intervening years.
A primary component of the warp drive method of propulsion in the Star Trek universe is the "gravimetric field displacement manifold," more commonly referred to as a warp core. It is a fictional reactor which taps the energy released in a matter-antimatter annihilation to provide the energy necessary to power a starship's warp drive, allowing faster than light travel. Starship warp cores generally also serve as powerplants for other primary ship systems.
When matter and antimatter come into contact, they annihilate — both matter and antimatter are converted directly into enormous quantities of energy, as electromagnetic radiation. In the Star Trek universe, fictional "dilithium crystals" are used to regulate this reaction. These crystals are described as being non-reactive to anti-matter when bombarded with high levels of radiation. Usually, the reactants are deuterium, an isotope of hydrogen, and antideuterium (its antimatter counterpart). The reaction chamber is surrounded by powerful magnetic fields to contain the anti-matter. If the containment fields ever fail, the subsequent interaction of the antimatter fuel with the container walls would result in a catastrophic release of energy, with the resultant explosion capable of utterly destroying the ship. Such "warp core breaches" are used as plot devices in many Star Trek episodes.