Cloaking device
From Wikipedia, the free encyclopedia
In several science fiction universes, a cloaking device is an advanced stealth system which causes a spaceship or individual to be invisible and extremely difficult to detect with normal sensors. However, the idea of a cloaking device could be extended to any object and is not restricted simply to spacecraft.
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[edit] Conceptual origins
[edit] Star Trek cloaking device
In Star Trek, cloaking devices were first introduced and used by the Romulans in the Original Series episode "Balance of Terror". The invisibility came as a surprise to the crew of the USS Enterprise, who considered it only a theoretical possibility. In a later episode, "The Enterprise Incident", the Enterprise is sent on a mission to capture one of the devices. Decades later, the episode "Minefield" of Star Trek: Enterprise contradicted this by revealing that Romulans possessed a form of cloaking technology in the mid-22nd Century, suggesting that what was featured in "Balance of Terror" et al was some sort of improvement, or that, for some reason, Starfleet Intelligence (or perhaps agents in the Temporal Cold War) suppressed knowledge of the cloaking devices encountered a century earlier. Enterprise also encountered several other races with cloaking technology, including briefly obtaining a cloak-capable pod belonging to the Suliban. In addition, the Mirror Universe Enterprise was also fitted with a Suliban cloaking device in the two In a Mirror, Darkly episodes.
The device was next seen in Star Trek III: The Search for Spock being used by Klingons. The original script of Star Trek III featured Romulans as the antagonists, but was rewritten to feature Klingons. Much of the plot relied on the use of a cloaking device, although prior to Star Trek III the Romulans were the only race to have developed cloaking technology. To explain how the Klingons acquired cloaking technology, fans have speculated that as part of an earlier mentioned Romulan-Klingon alliance, the cloaking device was given to the Klingons in return for warp drive. Critics of this theory point out that this requires the Romulans to have fought an interstellar war without faster-than-light drives. The Enterprise episode "Minefield" shows cloak-using Romulans in a system that was far away from Romulan space, which would certainly have required the use of a warp drive. The alliance must have existed, however, as Romulans have been seen using a Klingon ship in the original series. This has lead some fans to theorise it was this ship, the D-7, that was traded to the Romulans as opposed to the warp drive.
Cloaking is not perfect. In "Balance of Terror", the Enterprise was still able to detect the Romulan ship on motion sensors, and in the Star Trek: Deep Space Nine episode "The Search" we learn that running at a high warp speed may allow detection. The biggest weakness is that the device has such high power demand, it must be deactivated for a ship to enter combat. Thus, an alert enemy can target it normally when the ship decloaks. A major plot element of Star Trek VI: The Undiscovered Country was the invention of a new type of cloaking device that would allow firing whilst cloaked. However it was learned that the prototype ship using it could be tracked by plasma (gas) exhaust from the ship while moving at impulse.
In the Star Trek: The Next Generation episode "Redemption", the Federation discovers a way to use nets of tachyon beams to set traps for cloaking ships. "As detection methods advance, so too do cloaking devices", says Muckerheide.
Many have wondered why the Federation did not begin using cloaking devices after Kirk captured one. The reason is that Gene Roddenberry depicted a Starfleet that morally rejected such a "sneaky" technology despite the obvious strategic advantage being ceded to the Romulans. An in-universe explanation is that the Federation signed a peace agreement in 2311, the Treaty of Algeron, in which they promised not to develop cloaking technology ("The Pegasus"). Satisfied that the Federation would not develop threatening technology, the Romulans then turned their attentions inward, and for the most part withdrew from galactic affairs for nearly fifty years.[citation needed] However, the "The Pegasus" did depict a failed covert Federation programme to develop a phased cloaking device.
In Deep Space Nine, the Romulan Empire allowed the Starfleet to place a cloaking device on board the USS Defiant. Originally, the Federation was only allowed to use the device in Gamma Quadrant space, in exchange for any Federation intelligence gathered from the Defiant. However, that restriction soon was regularly ignored by Captain Sisko, who used the device to hide from Klingon vessels during the brief breakdown in relations between those two powers. It was also discovered that the Dominion could detect a cloaked ship by scanning the area with an anti-proton beam. It's not clear if the Federation is still prohibited from using cloaking technology, or if the two powers have since signed a new agreement regarding such technology.
Jem'Hadar warriors are born with the ability to "shroud" themselves naturally making them invisible to the naked Human eye and most sensors, though this cannot be achieved if the individual is suffering from Ketracel white withdrawal due to the intense concentration required. This concentration also forces a Jem' Hadar to stop shrouding before performing any action requiring focus, such as attacking. The Tosk, who are possibly related to the Jem'Hadar, possess a similar ability.
In Star Trek: Nemesis the Romulans developed a new cloaking device which was impenetrable to Federation scans. This was employed on Shinzon's ship the Scimitar. Like the Klingon ship in Star Trek VI, the Scimitar had the ability to fire and operate with shields raised while cloaked. The Reman ship's cloak was penetrated by telepathy.
[edit] Star Wars cloaking device
Cloaking devices play a much less significant role in the Star Wars universe. None of the movies show a ship cloaking, although it is mentioned. The first Star Wars reference to cloaking devices is heard in The Empire Strikes Back when Captain Needa states that no ship as small as the Millennium Falcon can be equipped with a cloaking device—however, the Expanded Universe has appeared to contradict this in places, mentioning that Emperor Palpatine's shuttle had a cloaking device, as did the personal spaceship of his early apprentice, Darth Maul. Various retcons have been proposed, most notably by Dan Wallace who suggests that this discrepancy could be retconned as Needa referring to power requirements of early hibridium cloaking prototypes, or possibly the power requirements of the old, failing, stygium cloaking devices. [1]
The Expanded Universe Star Wars books and games have included and elaborated upon cloaking devices, and have presented a solution to the earlier problem as to how big a ship has to be to be equipped with such a device: the original cloaking devices were small objects created from very rare naturally occurring stygium crystals. However, in later years (such as during the Empire) these crystals seem to have been depleted, with the surviving devices being extremely expensive, only ships as important as Palpatine's shuttle would be equipped with them. By the time of The Empire Strikes Back, the only cloaking devices known to exist (without the aid of stygian crystals) were much larger, and required vast amounts of power, as well as the design being an Imperial military secret. It is one of these far less practical devices that Captain Needa was referring to.
In the Star Wars Battlefront II game, a Bothan Spy has the ability to activate a cloaking device which also hides the weapon.
The plot of the Rebel Assault II video game concentrates on the danger presented by a type of TIE Fighter that can cloak, according to the game the first ship of the size with such a capability. This "TIE Phantom", a modified V-38, was the brainchild of the genius Grand Admiral Martio Batch. The new fighter had undergone some combat experience and entered production before the factory and all existing models were destroyed. The cloaking device of the TIE Phantom seems to be fueled by oridium ore and produces a "cloak field" that renders the fighter effectively invisible to both electronic sensors and human sight. The fighter becomes visible a short time before firing, suggesting the cloak field renders the ship double-blind. As the fighter cloaks or uncloaks, various parts of it fade in and out of view and the ship shimmers a blueish color. The TIE Phantom's cloaking device is considered by some to be more of an active stealth system with electronic systems to break up incoming sensor beams and a refractive surface covering to make it harder to spot visually.
In the Computer game TIE Fighter, The Vorksnix Project manages to develop an experimental cloaking device that is small enough to be used on a Corvette. However, it had a significant flaw in that it was very unstable when used in conjunction with a hyperdrive. Attempting to operate both at the same time would cause the ship to explode.
The Star Wars universe's cloaking devices were a major element of The Thrawn trilogy: it was explained that cloaking devices in the Star Wars galaxy are limited by fundamental laws of physics (in order to observe, one must be observable as well) and were never put into widespread use because of this limitation. The cloaking device renders a ship effectively "double-blind"; a ship using a cloaking device can sense nothing about its surroundings. Although a cloaked ship could fire while cloaked, it would be firing blindly and the probability of hitting its target would be minimal to the point of impracticality, even with the addition of a fire control predictor computer to the system. Worse, basic navigation was impossible, and a cloaked ship might end up fatally ramming an enemy ship or a friendly ship. Communication with a cloaked ship is also impossible.
Despite the Empire's attempt to produce and use a cloakable fighter, cloaking devices were never widespread in the Star Wars universe. Using the insane Dark Jedi Master Joruus C'Baoth, Imperial Grand Admiral Thrawn successfully implemented a plan whereby C'baoth would use the Force to communicate with the firing crews on cloaked Dreadnaughts, allowing him to A) fool the New Republic into thinking he had developed or obtained a weapon that could fire through planetary shields, which he had not, and B) in the ingenious conquest of the planet Ukio with its defenses intact. Ukio was an important foodstuff-producing plant vital to Thrawn's plans to rapidly expand his forces with clones, and when his fleet advanced Ukio activated their planetary shields, rendering them impervious to orbital bombardment. However, Thrawn had already positioned cloaked Dreadnaughts beneath the planetary shield, and using C'baoth's communication with the cloaked ships, he executed an incredibly well timed maneuver: his Star Destroyers would fire at ground targets that were directly underneath the cloaked Dreadnaughts; the Star Destroyer fire would be deflected by the shield, but C'baoth would order the cloaked ships to fire a split second later: to the observers on the ground, it appeared that the Star Destroyers were firing through the planetary shield, and Thrawn fooled them into thinking this was some sort of new superweapon which they had no defense against. The government of Ukio then contacted Thrawn and surrendered, with their planetary defenses fully intact for Thrawn to take control of. However, the ruse was eventually revealed, and with the death of C'baoth, cloaking devices were again rendered impractical for widespread deployment.
Grand Admiral Thrawn also devised a use in which a cloaking device was used to conceal several squadrons of TIE fighters and mole miners inside a freighter's cargo bay, which was then piloted into a heavily-used shipyard (Sluis Van). The freighter's cargo was cloaked instead of static damped, to reduce suspicion as to the surprise in the cargo bay. The freighter was scuttled explosively, and the fighters released in a surge to the complete surprise of the yard's defenders. This was timed to coincide with an attack by several Star Destroyers.
Thrawn also developed one additional tactic involving the use of cloaking devices- as a siege weapon. This tactic was only used once, involving, as it did, an enormous amount of resources, but it was highly successful. Essentially, Thrawn attacked the then-New Republic controlled Couruscant with a full fleet. As the battle progressed to the point that Thrawn wished, the Chimaera, Thrawn's flagship, began to launch 22 cloaked asteroids, knowing, and intending, that the energy of the launch would be detectable by surface based sensors. However, the asteroids were launched cloaked, and to further the confusion of the defenders, the tractor beam launcher had a shunt attached to it, allowing it to draw power- and thus be detectable on the sensor boards- but not do anything with it. So, when the New Republic military detected a grand total of 287 tractor launches from Chimaera, they were faced with the possibility of having to find up to that number of cloaked asteroids, in unstable orbits around Coruscant- without being able to lower the planetary shield until they were all gone for certain, as a 40-meter asteroid would do an incredible amount of damage on a planet with Coruscant's population density.
In the Dark Nest trilogy showed that the Chiss, a species that Thrawn belonged to, utilized a Star Destroyer design that featured a working cloaking device.
[edit] Other references
The title character of the Predator films uses an imperfect cloaking device; although the Predator is virtually invisible while stationary, movement causes a characterisic "shimmer" effect, and its wrist blades extend outside the field. Unlike the other mentioned types of cloaking field, the device equipped to the Predator Suit allows for continuous cloaking, even during hand-to-hand combat.
In the 1996 Doctor Who television movie based upon the long-running British series, Doctor Who, the Doctor's TARDIS was said to possess a "cloaking device" that got stuck, leaving it in the form of a British police box. This was a continuity break with the series (which always used the term "chameleon circuit"), possibly due to the film being partly produced by American broadcaster FOX, and/or desire for a more commonplace phrase. In the 2005 episode "Boom Town", Rose calls the mechanism a cloaking device, and the Doctor corrects her.
In the anime series Ghost in the Shell: Stand Alone Complex (continuing in its second season under the name "2nd gig") Section 9 employs "optical camouflage" suits which allow the wearer to render himself completely invisible. The older models did not hide shadows or body heat, but as Solid State Society suggests, later models were designed that cloaked even these methods of detection. Often characters using this optical camouflage will disengage it after using it for a short period of time, but they have been known to use it while firing and attacking. Presumedbly the camouflage eats away at a power source, so it's best used it short time sets. Sometimes the suits can be see slightly, and othertimes not at all; in episode 21 "Eraser", there is a scene where the Major can plainly see two enemies using optical camouflage, but it is unclear whether Section 9 simply has the best quality optical camouflage or not. In the series, the camouflage seems to become disrupted when it comes into contact with water, while in the original movie it does not.
In the 2002–2003 anime series Gundam Seed and its 2004–2005 sequel Gundam Seed Destiny, some mobile suits and space warships are cloaked using the synthetic prism-like particle known as Mirage Colloid.
In the Metal Gear series, portable cloaking technology is a reality. Within this series, the "stealth camouflage", as it is referred to, comes in the form of a small device about the size of a bulky CD player and in the MGS remake at the end, Otacons type resembles a bulky scientific calculator. When activated, the user becomes mostly invisible, save for a slight "ripple-effect" when in motion. Players can acquire this camouflage for themselves as a reward for accomplishing special task(s) prior to completion of the game. (ex. collecting all of a certain item, remaining undetected for the entirety of the game, or performance on special sections of the game.)
In Star Control and Star Control 2 the Ilwrath utilised cloaking devices on their Avenger vessels. These devices absorb all light meaning that the ship becomes cloaked in its space background, although good human pilots with a keen eye can spot them as they travel over stars which gives away their position. The Avenger, while cloaked, will attempt to ambush ships then use its hellfire cannon to turn it to cinders after achieving a very close range with the target vessel.
In the real-time strategy game Total Annihilation (TA) a small number of units have the ability to cloak, becoming invisible. The starting unit of both ARM and CORE, the Commander unit, has the ability to cloak. Other units which can cloak include the ARM 'Shooter' sniper Kbot and the ARM 'Infiltrator' and CORE 'Parasite' spy Kbots. The ARM 'Podger' and CORE 'Spoiler' vehicles can lay land mines which are automatically cloaked (although this feature can be deactivated to save energy if necessary). Both sides can build cloakable Fusion power plants. Cloaked units in TA will uncloak if they fire a weapon, use their nanolathe or if an enemy unit approaches within a specific radius, they will also uncloak if the player runs low on/out of energy. Also, although invisible, they are still detectable by radar. All cloaking devices (with the obvious exceptions of both mines and reactors) consume exponentially larger amounts of energy while moving, and fail completely upon the activation of a weapon or tool. With the exception of the Commanders, all other units with cloaking ability come with Total Annihilation: The Core Contingency expansion pack. Also present in TA are related concepts such as radar invisibility and radar and sonar jamming.
In the RTS game Homeworld one can build cloak generators to hide a fleet, and playing as the Kushan gives you access to the cloaked fighter. However, the technologies are far down the tech tree, and cloaked ships can easily be detected by proximity sensors or sensor arrays. Furthermore, the cloaked fighter has weak attack power, long construction time, and must decloak when attacking. In the sequel Homeworld II both races are able to build the cloak subsystem which performs a similar function to cloak generators.
In the RTS game StarCraft the Terrans possess cloaking devices, which allow Wraiths to turn invisible, as well as Personal Cloaking for Ghosts. The Dark Templar also learned how to bend light to make themselves virtually invisible. The Protoss Arbiter has the ability to automatically cloak all nearby friendly units, excluding the Arbiter itself and any other Arbiters. The Protoss Observer remains perpetually cloaked, but has no attack. In Starcraft cloaked units may attack without becoming uncloaked, but certain buildings and units with the Detector attribute can reveal their positions, allowing enemy units to target them. These include the Terran Science Vessel, Terran Missile Turret, Zerg Overlord, Zerg Spore Colony, Protoss Observer, and Protoss Photon Cannon.
In the TV series Stargate SG-1, Goa'uld Tel'tak cargo ships have an imperfect cloaking device which makes them invisible but still allows for detection; this has been modified (to the surprise of SG-1 and the dismay of the Tok'ra) by the System Lord Apophis to cloak entire Hatak motherships. Anubis, a partially Ascended goa'uld (and therefore in possession of some of the knowledge of the race that built the Stargates, the Ancients, who also Ascended,) regularly used al'kesh (mid-range bombers) that were capable of cloaking. (It was unclear if all al'kesh ships in all the goa'uld fleets could cloak, or just those used by Anubis and Apophis after his takeover of Sokar's fleet; since those are the only al'kesh ever seen to cloak, however, the latter possibility seems more likely.) There are also cloaking devices that cloak individual persons, such as the one that Nirrti uses. These cloaks can be counteracted by Transphase Eradication Rod. The Puddle Jumpers in Stargate Atlantis (as well as Atlantis itself) have cloaking devices that make them completely undetectable to all known sensors as well as the naked eye. Finally, the Sodan use a personal transphase cloak (similar in technology to Merlin's hidden display) and which has also been acquired by for use by SG teams as depicted in Uninvited (Stargate SG-1).
In the computer and video game Deus Ex, one of the types of augmentation canister the player finds allows them to choose between either cloaking, or radar transparency, making them invisible to either humans and animals, or robots and cameras, respectively. These augmentations cannot be used for very long because of their extremely high power requirements, especially if used in conjunction with other augmentations.
Almost all larger fleet craft (battleships) have the ability to cloak themselves in the video game series Colony Wars. In this mode they are invisible, cannot attack, and cannot be attacked.
Cloaking devices are one of the items used in Super Smash Bros. Melee. Any character who uses it remains vulnerable to enemies' attacks but their damage percentage does not increase. The item’s trophy states the game of origin to be “Top Secret” but appears to be an allusion the Nintendo 64 game Perfect Dark.
The Command & Conquer series by Westwood Studios has multiple instances of cloaking. In the original Command & Conquer game, Nod had the capability to build stealth tanks armed with missiles, the tanks were completely invisible but uncloaked if they came to close to an enemy unit or fired their weapons. In Red Alert: Counterstrike, a tank that fires missiles can cloak, but uncloaks if it gets too close to an enemy. In Command & Conquer: Red Alert 2, Albert Einstein creates a "mirage tank" which can changes its outward appearance to look like vegetation. In Command & Conquer: Tiberian Sun, the Brotherhood of Nod can create Stealth Tanks, which are invisible except to special sensors until it uncloaks to fire missiles. Also the Brotherhood has the ability to create large cloaking devices that can cloak entire bases, making the area of a base seem like empty ground.
In Douglas Adams' Life, the Universe and Everything, the third novel in the Hitchhiker's Guide to the Galaxy series, Slartibartfast's ship, the Bistromath, utilizes a Somebody Else's Problem field. The SEP field relies on the mind's propensity to ignore anything which is it not expecting to see or cannot explain. This technology was developed because "the technology required to actually make something invisible is so complex that most of the time it's simpler to take the thing away and hide it." The technology is much simpler than a cloaking device because it relies on human nature, and in addition can be run for centuries on a single 9V battery. The main disadvantage to the SEP field is that the cloaked object needs to be unexpected, thus the Bistromath is designed to look like a giant Italian running shoe, and another field is mentioned hiding a mountain after painting it bright pink.
In the Nintendo game Metroid Prime, a select group of Space Pirates had access to cloaking technology; these are Shadow Pirates. The cloaking technology used up most of the user's energy, which forces them to rely solely on melee weapons in battle. Also because of a design flaw, the cloaking devices gave off high heat ratings, making it possible for players to track down a Shadow Pirate with the Thermal Visor. A few other enemies in the Metroid Prime series featured a cloaking-like device, but could only be seen though different methods.
In Marvel Comics' X-Men series, the superhero group's jet the Blackbird possesses a cloaking device that makes it invisible to both radar and the naked eye. In the 2000 film adapatation, the group's jet is only capable of blocking radar devices.
In the James Bond film Die Another Day, Bond's Aston Martin Vanquish is equipped with a form of Active Camouflage, which worked by having embedded cameras capture the view from one side of the car and then somehow projecting that same view onto the other side.
In the animated television series Exosquad, cloaking devices based on dark matter from the planet Chaos were a rare technology that only the Pirate Clans possessed.
In Master of Orion, a space based strategy game, there were also cloaking devices. In the sequel to that game, Master of Orion II, there were three distinct types of cloaks. The weakest , the "stealth field", merely made ships impossible to detect when not engaged in battle. The "cloaking device" had the benefits of the stealth shield as well as making it harder for weapons to target an equipped ship. The strongest cloak is the "phase cloak" which had all the benefits of the cloaking device but could also for a limited time period put the ship in a phase in which it is completely invisible but unable to attack.
In the British sci-fi comedy show Red Dwarf episode "Backwards", Starbug 2, upon landing in backwards London, engaged a cloaking device to hide it from the locals.
In the Jean-Claude Van Damme movie Street Fighter, Col. William Guile's stealth boat used a form of adaptive camouflage, similar to a cloaking device, that was susceptible to detection by motion, and by being able to see the wake of the boat
In the Wing Commander games, notably Wing Commander 2, experimental Kilrathi fighters are equipped with cloaking devices. In rare occasions, cloaking torpedoes were used against friendly capital ships. Since the cloaking device was experimental and not yet perfected, the experimental ships and torpedoes would occasionally "flicker", allowing a quick player to briefly target them and fire. Luckily for the player, due to the high power consumption of the cloaking device, there wasn't much energy available for defensive shielding.
In the Halo series, an alien confederation of several races known as the Covenant have developed a type of active camouflage that allows several of their species to become semi-invisible in ground combat. In Multiplayer mode, an active camouflage item is available to the player and can be set as standard for certain matches.
In the Xbox videogame Brute Force, Hawk, one of the four playable characters, is able to use a cloaking device to hide from enemies. She is also equipped with a melee weapon known as a "Powerblade", which she can use to eliminate enemies after getting close to them, usually using the aforementioned cloaking device. Hawk can attack while cloaked, but this depletes the device's battery rapidly, and she usually must uncloak before attacking. Hawk can also move very fast, but has low hit points, and relies on the support of the other characters in heavy combat situations.
In the PC & 3DO game Star Control II, the Ilwrath Avenger has a cloaking device usable in combat situation which renders the ship black as space, thus making it harder to be targeted and disabling homing capabilities of missiles or the Arilou or Earthling homing lasers. The cloak is not perfect, because the ship is still on the other side of the screen and also the ship can obscure stars in the background, hinting its position. There was also a rumor of a "Cloaking Device" artifact usable by the Flagship on a Star Control discussion board. Someone even posted a fake screenshot with its whereabouts. The rumor was eventually dismissed, however, the primary developers of the game, Fred Ford and Paul Reiche III revealed their plans to include such a Cloaking Device when Star Control II was still in development. The idea got scrapped because of the lack of time to implement it.
The PC game Deus Ex gives the player a choice to install one of two kinds of cloaking abilities in the augmented body of the main protagonist, JC Denton, after finding a certain item. The first makes him invisible to humans and other biological creatures, and the other will enable radar transparency that makes him undetectable by cameras, robots and automated turrets.
[edit] Scientific experimentation
An operational, non-fictional cloaking device might be an extension of the basic technologies used by stealth aircraft, such as radar-absorbing dark paint, optical camouflage, cooling the outer surface to minimize electromagnetic emissions (usually infrared), or other techniques to minimize other EM emissions, and to minimize particle emissions from the object. The use of certain devices to jam and confuse remote sensing devices would greatly aid, but are more properly speaking "active camouflage." Alternatively metamaterials provide the theoretical possibility of making electromagnetic radiation appear to pass freely through the 'cloaked' object.
[edit] Philadelphia Experiment
The Philadelphia Experiment was a supposed secret experiment conducted by the U.S. Navy at the Philadelphia Naval Yards at Philadelphia, Pennsylvania, on or before October 28, 1943, which went horribly awry. The experiment was allegedly to cast a veil of radar and possibly optical invisibility or transparency around a ship. Though most mainstream experts argue the incident is an urban legend, a number of people argue that the Philadelphia Experiment could be genuine. Whether true or not, the Philadelphia Experiment has had a major ripple effect on conspiracy theory, and elements of the Philadelphia Experiment feature in many other conspiracy tales and provided the basis for various movies and miniseries.
[edit] Metamaterial research
Optical metamaterials have featured in several recent proposals for invisibility schemes. "Metamaterials" refers to materials that are a composite of two or more optical materials combined into a structure that effectively has new properties quite different from its constituents (most famously, a negative refractive index is possible).
On February 14, 2005, Andrea Alů and Nader Engheta at the University of Pennsylvania announced in a research paper that plasmons could be used to cancel out visible light or radiation coming from an object. This 'plasmonic cover' would work by suppressing light scattering by resonating with illuminated light, which could render objects "nearly invisible to an observer." The plasmonic screen would have to be tuned to the object being hidden, and would only suppress a specific wavelength: An object made invisible in red light would still be visible in multiwavelength daylight.
A concept for a cloaking device was put forward by two mathematicians in one of the UKs Royal Society journals [2]. Shortly afterwards, blueprints for building a cloaking device were put forward in the journal Science by researchers in the US and UK [3]. However, "Scientists not involved in the work said the plans appear feasible but that they would require more-advanced substances than currently exist" [4].
While no one has yet been able to make a cloaking device for light, in October 2006, a US-British team of scientists created a metamaterial which made an object invisible to microwave radiation [5]. Since light is just another form of electromagnetic radiation, this is the first step to a cloaking device for light, though much more advanced nano-engineering techniques will be needed due to light's small wavelength.
[edit] Duke University experiments
On October 19th, 2006 the AP reported that a team of British and American scientists had demonstrated a prototype metamaterial based device that rendered a copper cylinder invisible to microwaves. In the prototype, microwaves passing through the cloaked object were significantly dimmed but the researchers believe this behavior can be improved. [6]. Engineers David Schurig and David Smith of Duke University successfully, although not completely, hid or "cloaked" the central copper ring by surrounding it with concentric rings of metamaterial standing one centimetre tall and spanning 12 centimeters. The rings were sandwiched between two plates so that microwaves could only travel through the cloak in the plane of the rings, as described in the paper published online October 19, 2006 by Science.
[edit] Active camouflage
Active camouflage (or adaptive camouflage) is a group of camouflage technologies which would allow an object (usually military in nature) to blend into its surroundings by use of panels or coatings capable of changing color or luminosity. Active camouflage can be seen as having the potential to become the perfection of the art of camouflaging things from visual detection.
[edit] Optical camouflage
Optical camouflage is a kind of active camouflage in which one wears a fabric which has an image of the scene directly behind the wearer projected onto it, so that the wearer appears invisible. The concept exists for now only in theory and in proof-of-concept prototypes, although many experts consider it technically feasible. It is an example of active camouflage (or adaptive camouflage).
[edit] See also
[edit] References
- Mosnews Dr Oleg Gadomsky Cloaking Device Article
- MSNBC: Can objects be turned invisible?, detailing the research of Engheta and Alù.
- Optical Camouflage by the Tachi Lab in Japan Optical Camouflage by the Tachi Lab in Japan
- BBC Science - Experts create invisibility cloak - Thursday 19/10/06
