Physics

Force Fields

These are an outgrowth of better understanding of quantum electrodynamics; the popular-science explanation is that they consist of vigorous lying to the Pauli exclusion principle. Physically, they consist of large numbers of electrons in a subtly patterned wave, and they usually emit a healthy electrical zap when they fail. Much incoming energy is simply deflected, while some is absorbed as heat that needs to be dissipated in some way. A full-powered force field in atmosphere has a distinctive sparkle caused by repelling the atoms of the air around it. The best attack against a force field is another force field that can merge with the first one; if you can do so without setting off alarms in the equipment maintaining the first field, you can then do unkind things like hook it up to a grounding cable (if you have a planet handy), shorting out that entire segment of the field for a few seconds. (Planet-based fields never touch ground to avoid this problem, which is why the Imperials had to send in ground forces against the base on Hoth in The Empire Strikes Back.) Matching fields without setting off alarms is a job for a highly trained specialist.

The easiest force field to create is the kind used as a door or prison cell, where the emitters completely surround the field. High-powered ones can repel matter with a very high momentum; low-powered ones, called particle screens, will let a macroscopic object through with a feeling like walking through a soap bubble, while bouncing most molecule-sized impacts. These are often used as substitutes for airlocks in civilian starships, though most freighters have at least one real airlock for use in case of power failure. Since particle screens operate at such low power levels, their sparkle is extremely dim and only visible to a dark-adapted eye. Some luxury droids are equipped to project a bubble that will deflect inclement weather, or block the transmission of sound; some swoopbikes have particle screens to cut down wind chill and avoid sucking in bugs.

The next step up is the repulsorlift; since a push on a force field pushes its emitters, it is so named because it pushes the vehicle away from the ground. A repulsorlift field is spongy, mostly invisible (save for dust, rain, and snow around it), and can’t go much further than the width of the vehicle (or several multiples of it, if designed for that, as in the case of most hovering droids); repulsorlift craft that build up speed can reconfigure the field’s shape so the entire vehicle becomes a ground effect vehicle and attain low altitudes, but they don’t truly fly like swoops; you drive a speeder and pilot a swoop. The field spreads the weight of the vehicle over the vehicle’s entire footprint, and won’t deflect any serious weapons. Physicists are usually tired of explaining that repulsorlifts aren’t antigravity, as that’s a completely different technology used in swoops and starships (though swoops and starfighters usually have repulsorlift capability as well), and only the most pedantic insist on correcting people who get the two mixed up. Repulsorlifts are more expensive than wheels or legs on a vehicle or droid, but are much lower-maintenance.

A deflector shield is more challenging to create. They require numerous synchronized emitters working together that creates a field that can completely surround the emitters. The smallest ones developed to date are on starfighters and grav tanks.

Deflector-style emitters can also create particle screens, and many warships have these distributed throughout their volume with automatic triggers to activate if there’s a sudden pressure drop or the fire sensors go off.

Tuning a force field to scatter laser beams decreases the acuity of your optical sensors, but protects you from lasers, which is why such weapons are largely considered obsolete. At lower levels of power, the same effect can be used to create privacy screens.

Force fields can also be used in atmospheric propulsion, using moving fields to push air through a tube; this is called a field thruster. They’re the most efficient way to turn electrical energy into propulsion, but if you’re already burning fuel of some sort, it’s better to just use an advanced jet engine. And if you’re already using a fusion reactor, it’s easiest to just use an ion drive.

Traction fields

Another offshoot is the traction field, using the force field to develop a very high coefficient of static friction with a nearby surface. Repulsorlift vehicles can ripple their lift cushion to move slowly— speeders never have to parallel park, as they can just move sideways— or dig into soft surfaces to decelerate quickly. Hovertanks rely on these.

Traction fields can also be used on chemical workbenches, creating pools for various reactants (including acids that might eat through normal vessels) and then dynamically combining them. They are also used in expensive user interfaces to create tangible buttons to push, their boundaries highlighted through small holoprojectors.

Gravitonics

The essence of gravitonic technology is the manipulation of gravitic knots, which are subatomic-sized twists of spacetime that require the powerful gradients of black holes (naked singularities in particular; an ordinary black hole won’t do) to manufacture. (This is perhaps a result of developing loop quantum gravity.) Due to conservation, knots that are formed from charged matter retain an electrical charge, which allows them to be contained and manipulated by electromagnetic fields. Their containment vessels must always retain a charge, or the knots will simply fall through ordinary matter. They slowly decay over time (with a half-life of about a century in a storage tank and about a decade under normal use), so a civilization cut off from a supply of them will gradually lose the ability to manipulate gravity.

Antigravity makes it easy to maintain a given altitude at negligible energy cost. An antigravity plate consists of a flat plane containing tumbling knots that scatter incoming gravitons back along their path; Newton’s Third Law is satisfied with the force on the plate being distributed throughout the mass generating the gravity in the first place. This is only noticeable with extremely sensitive equipment, and it’s perfectly safe to stand under a hovering Imperial Star Destroyer. Standing on top of an AG plate shields you from the gravity coming from the immediate column of matter under your feet, but not from the vector sum coming from the rest of the planet minus that cylinder, so you feel almost the same force. AG plates tend to vibrate with a wavelength based on the dimensions of a vehicle, which is why you hear high-pitched thrums from small devices and low-pitched ones from large ships; these can be damped out for an extra price.

Spaceships have an additional device in their repulsors, called a geometry buffer, which stores gravitational potential energy in a fabric of knots, caught in an electromagnetic force field, for later release on ascent. This is the key to cheap interstellar shipping. (TO DO: work out the amount of energy this is, and how easy it is to notice when it’s suddenly released by blowing up a starship.)

Starfighters have an additional gadget called an etheric rudder that allows them to redirect their momentum while within an existing gravity field, making it possible to execute tight turns while in low orbit; the ship’s original momentum radiates as gravity waves, and any space battle is very noisy to grav sensors. The lower the gravitational gradient, the less useful the rudder is. Engineers call it an etheric keel-rudder assembly.

Grav plates are the source of the artificial gravity inside starships and space stations; they consist of panels of circulating knots that release and absorb gravitons. They can also be used to cancel normal gravity on a planet, allowing people to train for free fall without having to leave the planet, and providing a basis for palanquins for visitors from low-gravity worlds; they’re called sleeping plates when used to provide a zero-gravity bed, with a computer adjusting the fields to keep a sleeper floating in the middle of a space of warm air, and float-jail when used to keep a prisoner hovering out of reach of any walls. Grav plates need to be on ceiling and floor to set up a simple graviton current in a spacecraft; they need to angle up from the floor at the sides to create free fall on a planetary surface. The net system, observed from outside, does not change weight.

Tractor beams are fields of force, but they are not based on the same technology popularly referred to as force fields. Rather, they are graviton projectors, and they exert the same force on their mounts as they do on the object they pull on.

Acceleration compensators are similar to grav plates and tractor beams; they are hooked up to both accelerometers and the ship’s drive and are used to counteract the effects of acceleration on fragile passengers and cargo. Most of them are designed to counteract the main drive, but they also help keep people from being thrown around by impacts. In military vessels, they’re powerful enough to help maintain structural integrity.

Hyperspace and Subspace

Hyperspace cannons and, later, hyperdrive were invented on Corellia, and the corresponding physical phenomenon was called hyperspace there. Subspace radio was invented on Duro and its propagation medium was dubbed subspace. The underlying phenomenon is the same: another aspect of physical reality where travel maps to great distances in the our more familiar realm, dubbed realspace by the press, despite protests from physicists, who refer to it as basis level. It doesn’t help that hyperspace engineering is ahead of hyperspace physics; hyperdrive was reverse engineered from Rakatan technology.

This continuum has a number of energy levels; the higher the energy level, the broader the mapping to realspace, and a shorter journey it takes to translate into the same distance when exiting to realspace. The cost of translating to a given energy level is inversely proportional to the wavelength of the energy being translated. Radio waves in the range of a meter or so can easily be boosted up to levels so high that the signals propagate at many light-years per second; matter, on the other hand, has drastically shorter wavelengths and can only be practically boosted to the speeds associated with hyperdrive. The only difference between subspace radio and hypercomm is the energy levels used to send the signals. No one has yet worked out how to create a device that allows listening to radio waves on higher energy bands while traveling in lower ones, so ships in hyperspace are cut off from communications.

The technical commentaries are well done, though I’m establishing that there is a reference frame provided by the galaxy itself; as velocity relative to the nearby stars increases, the cost of accessing hyperspace increases precipitously. Because of this reference frame, ships leaving hyperspace have a similar velocity relative to their new neighborhood as they did to the one they left. Ships and planets moving at less than relativistic velocity can enjoy near-instantaneous communication with anyone within several light years; wars have been fought over subspace bandwidth allocation. If a star system is moving at a noticeable rate relative to the surrounding neighborhood, it’s necessary to drop out of hyperspace, spend some time in sublight to get into its area of influence, and then jump back into hyperspace to finish the trip there.

Activating a hyperdrive deep in a gravity well is a good way to make a hyperdrive explode, and is not a terribly efficient way of delivering damage.

Stardrives leave ion trails that can be tracked with sufficiently good sensors. A starship entering or exiting hyperspace leaves distinctive ionization patterns called hyperdust.

The HoloNet does not yet exist; there is a patchy subspace packet relay network. Subspace radios suitable for light freighters have a range of light-minutes to light-hours. Capital ships can carry ones with ranges of tens and even hundreds of light-years, and the massive Subspace Node 1 orbiting Coruscant can broadcast thousands of light-years.

The safest way to travel in hyperspace is to follow a chain of jump beacons, powerful computers that track all known masses in the area, talk to their neighbors via hyperwave, and provide navigation information to starships. Jump beacons often serve as high-bandwidth information relays as well. Since control of a jump beacon can make life very easy for pirates, beacons on major trade routes are well-manned and well-defended stations. Jump beacons are usually owned by banks or mercantile consortia and charge a modest fee, with a discount for uploading sensor log data after a jump to provide feedback.

Energy Production

Tibanna is a prime element that has an extremely low threshold for nuclear fusion, particularly when all of its nuclear spins are aligned. Mixing small amounts with ordinary hydrogen can lower the threshold for a fusion reaction; in high proportions, it can trigger fusion even in a blaster pistol.

The standard power plant for anything from a capital ship to a continent is a large gravitational fusion installation. Ordinary protium (hydrogen with no neutrons) is fed into a containment chamber that is lined with a force field, and numerous graviton projectors fire carefully tuned beams that constructively interfere at the center of the reactor. This creates the density necessary to run proton-proton fusion, just like in the hearts of stars. The gravitational gradient keeps most of the plasma from even touching the force field, and the force field only lets light out. The walls of the chamber are lined with free-electron photovoltaic cells (basically a specialized form of programmable matter acting like a free electron laser in reverse) that can capture even gamma rays and convert them to useful electrical power.

Fightercraft, light freighters, and small space stations use smaller gravitational fusion plants that require deuterium, ³He fuel, and a bit of tibanna, with a highly explosive primer fuel that helps start and sustain the reaction. (The massive terraforming station above Telos in KOTOR 2 was staying up on antigravity rather than being in a proper orbit, so it needed to minimize the supporting mass that was handling those huge force fields, necessitating deliveries of such primer fuel from Peragus II.) Liquid-metal lithium tibannide is a dense but volatile fuel that can used in place of ordinary tibanna in some fusion plants.

Man-portable fusion furnaces use bubble fusion, and are commonly used to provide electrical power and heat for extended field activity. Smaller, more expensive systems run on tibanna.

Smaller vehicles like swoops use fusion furnaces, hydrogen fuel cells, converting hydrogen and oxygen into water, or batteries; some burn synthetic organic fuels, which still have rather good energy density.

Fusion plants of all kinds put out lots of neutrinos. The only way to mask this is to hide in the flux coming from a nearby star; starships that need to go into stealth mode generally switch to fuel cell power.

The most extremely energy-intensive applications use hypermatter, which is an exotic form of matter that is used in hypermatter annihilators.

Agricultural, colony worlds, and stealth installations that need to avoid neutrino emissions will use anything from solar collectors to geothermal taps (often created using tunneling droids to sink a shaft down a few thousand feet; it can take work to conceal the infrared emissions, though, and can cause unwanted seismic activity). Getting knocked all the way down to biofuels, internal combustion engines, and wheels is a sign that a civilization has been particularly hard-hit. Hydroelectric power is rather quaint and seen as relatively unreliable, because people think in the long term and will naturally ask, What about a drought? (No one would think of using petroleum for fuel; it’s too useful as a source of complex organics that can be used in fabrication.

Sensing Technology

The photoreceptor is very different from the charge-coupled device; it is an ancestor to the free-electron photovoltaic cells used to collect energy in fusion plants, and it converts incoming photons to energy proportional to the frequency. Instead of producing distinct red, green, and blue profiles like a CCD, it produces a histogram of colors. (Digitized images take up a great deal more space than the ones we’re familiar with.)

Starship sensors are usually based on radar and ladar (which are now a continuum of related techniques spanning frequencies from radio to ultraviolet). Ground-penetrating lidar can be used from low orbit to locate hidden bases, though it requires a good while to do the sensor sweeps.

Terahertz imaging is used for security scans. Medical deep-scans are synthesized from contrast-enhanced ultrasound, terahertz imaging, photoacoustic imaging, and near-infrared imaging. Magnetic resonance (usually low-power), positron emission, and computed X-ray tomography imagers are rings that pass over your bed, and are used to develop base models.

Desorption Electrospray Ionization (DESI) (which can do very fine sampling on fingerprints) and optical frequency comb spectroscopy can be used to do mass spectrometry in the field when microarrays of scent receptors aren’t accurate enough. (A modern device weighs 20 lbs.) Chemical sensors often make use of microfluidic and nanofluidic processing and nanoscale magnetic effects.

Neutrino detectors are used to locate operating fusion reactors. They can detect starships and concealed installations that are otherwise impossible to locate. (TO DO: work out the sizes for neutrino detectors of various efficacies. Capital ships should be able to scan for small ships; it might be useful for small ships to be unable to detect anything smaller than a capital ship.)

Buildings, vehicles, and roads are usually equipped with ultrasound radiators and sensors, or are coated by or contain threads of conducting nanotube filaments, allowing monitoring for cracks and damage. In a starship, all but the smallest hull breaches are localized very quickly.

Image Display

Displays use the same technology as photoreceptors in reverse. This avoids issues with the differening photopigments in various species’ eyes. Flatscreens are simple, but mid-air projection is also available even without holography.

Holography is in common use, but there is no way to make a holographic image opaque or invisible (so no holoshrouds). They are usually displayed in windows that have a black background to provide the illusion of solidity. The technology for projecting holograms without a screen uses the same underlying mechanism as force fields to scatter light at a distance. No one has yet managed to warp light itself enough to create a cloaking device... or if they have, they aren’t telling. (A cloaking device would be a specialized force field that channels incoming photons from outside to roughly the other side of the force field, and reflects all the ones inside. It would allow a starship on a ballistic trajectory to be very difficult to detect other than when it actually transits a light source.)

Interfaces have had thousands of years of improvements, and it’s common for pilots to be immersed in augmented reality, where their ship’s sensors integrate all available information to maximize the utility of the pilot’s senses. The visor on a headset will show a 360° view, as if the cockpit and the rest of the ship were transparent. While the vacuum of space doesn’t carry sound, the computer will synthesize the sounds of nearby engines, weapons fire, and surfaces rushing past to aid in the mental mapping for the pilot, creating Doppler effects as appropriate. This is sufficiently common that even windows on spacecraft are hooked up to well-camouflaged speakers that allow spectators to gain the same benefits, and causes many tourists to develop mistaken impressions about how sound propagates.