Jumpspace Physics

Credit to Ensyn for help with lore

"Even though it is, to the wise creature, indisputable that fire is the most important invention any civilisation will ever make, what the second most important invention is is much more controversial. Some might say it is agriculture or otherwise animal husbandry, as it gives a culture the food it needs to grow great. Some might say it is writing, as it allows a culture to remember, to truly learn. Some, more bold ones, might say it is electricity, as it turns any culture into near-gods. I, on the other hand, I would say that the greatest is jump-travel, the one technology that allows a people to leave the prison of their home system, and be free at last." -Philosopher-poet Tahra'zak krah Krohoata, Musings on the Universe and Her Inhabitants

Within Known Space multiple forms of faster than light travel have been invented. In the present day, all of these methods utilise the phenomenon informally known as 'Jumpspace' to get around the limitations of travel in the material universe. FTL has become a staple of every spaceborn civilisation, and the current era of the galaxy is often referred to as the Jump Age in the same way that past periods of species histories are often divided into ages based on the best metal or other technology they could master at that time (like the Iron Age for an example). Resources to facilitate (easier) FTL travel have caused more than one war in Known Space.

Jumpspace

"It is amazing that we discovered this... realm in the first place, that we managed to gain some understanding of it. Infinite layers, infinite possibilities.... Infinite opportunity. I tell you, mortal minds were not designed for infinity, and yet here we are. A people, an Empire, made large purely through attempting to reach the unreachable." -Seer Certainty of the Pathbringers, in their personal memoires

All currently known forms of Faster Than Light travel deal with jumpspace in one way or another. The universe is not, as many pre-Jump civilisations think, one. Instead, it consists of many so-called 'Layers'. It is theorised that our 'universe' is the lowest possible Layer of the Metaverse, and there is an infinite amount of layers. Layers higher than our universe are known collectively as Jumpspace, due to the potential to 'jump' through them. With every 'higher' Layer of Jumpspace the speed of light (from here on out referred to as 'c') increases, the rate at which it increases appears to be neither linear nor exponential and is not fully understood at the present. The distance traveled mostly stays the same, however. Because c is higher in higher layers, energy becomes more 'potent' as e=mc^2. This means spacesjops through higher layers have a tendency to explode, as too much energy is being used. Because c is higher, light also bounces around more which means that light from, say, a lamp can become highly dangerous, causing radiation sickness and cancer much more easily. This, however, also means that the space of higher Layers is warmer, and there is an easier time to gain energy. This, in turn, has caused for some higher layers to have developed spaceborn lifeforms, often gigantic in size (only being limited in the sizes they can sustain by the amount of food they can find, and by the gravity their own bodies produces). These lifeforms are usually benign, though some have proven hostile and predatory towards ships travelling to Jumpspace, though that has only rarely proven to be an issue.
Apart from this, there is also the phenomenon known as the Layer Integrity Field (or lif, for short). Every layer has its own form of lif. The Layer Integrity Field can be seen as the 'rhythm' or 'ID' of any specific layer. It is the field a universe naturally produces that makes reality possible, and without it things simply stop to exist, being erased from the Metaverse as a whole. Every layer has it's own unique lif, and the matter of that layer is tuned to that specific lif. If traveling to an other layer, objects with mass take some of their layers native lif with them into the new layer. This caused the two types of lif to 'clash', as it is impossible for two types of lif to co-exist. Because the lif of any layer is theoretically infinite, but the lif an object takes with it directly scales to the amount of mass it has, the native lif of a layer will always 'win' from objects brought in through inter-layer travel. This makes the amount of time one can spend in jumpspace inherently limited. Any phenomenon that does not have mass (such as electromagnetic particles) is not affected by lif, and can therefore freely travel between layers.
Gravity and similar space-time distortions have been found to also affect any higher Layer. Gravity, however, often has weird effects on Jumpspace, causing objects travelling to areas with high gravity to often be crushed, explode, or implode in some way. Black holes, especially, have extremely strange and poorly understood effects on Jumpspace, causing strange time distortions or for certain materials to form.
It is also important to mention so-called jumpfields. Jumpfields are naturally occurring phenomena on the quantum level where a jumpfield is naturally born. These fields allow any object with sufficient kinetic energy to enter jumpspace, though they will usually return to their original layer once this energy is lost. This explains the sometimes sporadic appearance and disappearance of particles on the quantum level. It is also sometimes theorised that this is a way for 'lost' energy or matter to return to their own native layer.
Similarly, there exists a phenomenon known as jump-barriers. This phenomenon is currently poorly understood. Essentially, some extended parts of the galaxy appear to have certain conditions that make it almost impossible to enter or leave jump inside them. How this affects quantum physics is currently unknown. These barriers are often utilised by various spaceborn civilisiations as natural defences, at the cost of it being much harder for them to attack or even have commerce with other species as well. Within Known Space, there are only a few, small jump-barriers, usually only encompassing one or maybe five systems. In the Unknown Reaches, however, multiple extremely large jump-barriers have been encountered, effectively blocking entire segments of the galaxy off. This partially explains why these areas are in the Unknown Reaches. The origins or causes of Jump-Barriers are hotly debated, with some even theorising that they are artificial in nature, and created by some kind of Precursor.
Jumpfield-Projectors, The Discovery of Jumpspace and Autonomous Jump-Travel Edit "I am proud to announce that we have done it. We have found the loophole. The loophole of the universe, which the gods left us to spread our glorious Kingdom over the stars. The one way around the speed-iimit of the universe: Jumpspace." -Shakaran scientist Teshrokr Mabashatsh, in her speach announcing the discovery of Jumpspace Many civilisiations will eventually discover Jumspace and its effects on quantum physics. This most usually happens when the civilisiation in question has already harnessed the powers of fusion or perhaps kugelblitz blackholes. This is because the discovery of jumpfields requires a quite impressive understanding of physics, and a great energy budget that only cultures of this calibre tend to posess. Most usually, the first quantum jumpfields will be discovered either in some government-funded research to understand quantum physics in general (especially by more knowledge-loving cultures), or in some attempt to weaponise or otherwise utilise quantum physics for economic gain. Due to the implications Jumpfields have on the nature of the universe, it is almost always seen as a monumental and ground-shaking discovery by those who discover it. After this initial discovery, most civilisiations look further into this phemenon. Often resulting in ways of detecting natural jumpfields, and also in theories of something similar to jumpspace existing. However, not much more progress is usually made untill a civilisiation starts the construction of a dyson swarm around its sun. After only a few years, this will result in an exponential and more than dramatic increase in the available energy budget of this civilisiation. As such, much more experimentation with jumpfields becomes possible. Eventually, researchers find a way to artificially create quantum jumpfields, and experiments with that often prove that particles travel faster than light through Jumpspace. At this point, governments, militaries and private corporations usually become much more interested in this new, growing field of physics. This combiend with the ever-expanding dyson swarm leads to much more discoveries.
Eventually, the first true Jump-Projector prototypes are created, by simply upscaling the aritificial quantum jumpfields to a more usable size. These new projectors are essentially a technology not entirely unlike a large particle accelerator, imitating the natural phenomena that lead to jumpfields forming but on a much bigger scale. Initial Projectors can usually only generate comparatively small fields, and take up way too much energy to be an economically viable method of transportation. At this point, the first tests with sending small drones and the like into jumpspace are performed, which usually result in the destruction of these drones as most civilisiations at this stage will not know of lif or the effects of gravity on Jumpspace.
Experimentation will usually continue though. Researchers will discover that is possible to enter Jumpspace at the outskirts of their homesystem, and will slowly begin to understand the mechanisms of lif. Slowly but surely, Jumpspace and by extension Jumpfields will be better understood, eventually resulting in the first true Jumpfield-Projector.
It is important to explain the exact mechanisms of the Jumpfield-Projector here. Essentially, the Projector will, as the name implies, project a jumpfield encompassing the entire ship. Now, any object that reaches an appropiate speed (or, by extension, heat, as heat is essentially just the speed at which molecules vibrate) it will be transported into Jumpspace. The higher the speed when the transportation happens, the higher into Jumpspeed one will come. Though, if a ship reaches the appropiate speed to, say, reach the 700th Layer of Jumpspace, it will first need to travel through all the 699 previous Layers. Once a ship starts slowing/cooling down, it will similarly begin it's 'descend', moving back through all 700 Layers untill it reaches Realspace again. The exact speeds one needs to maintain to reach Jumpspeed directly correlate to how far from the Jumpfield-source one is, and how powerful the Projector is. At the outskirts of the field, one needs to reach great speeds to enter Jump, but right next to the Projector (especially the more powerful models) even simply walking can transport one to Jumpspace, which is usually lethal. The Projectors are usually quite large and take up great amounts of energy, the smaller models still take up at least one room, with some of the biggest models even taking up an entire ships deck.
Eventually, the first primitive Jumps are made, which usually end up in the probe (or, in some regrettable cases, the ship) being lost in Jumpspace forever. This is because one needs to decelerate within Jumpspace to get back to Realspace. As such, most Jumps aim for star systems and the like, relying on the gravity to slow them down enough to reenter Realspace. Eventually, this too is discovered, and the first form of Jump-Travel is brought into use: Autonomous Jump-Travel.
Autonomous Jump-Travel is the most precarious form of Jump-Travel. These days, it is rarely used for most commercial interstellar travel. It involves only the ship in question, and its Jumpfield-Projector. Before going into Jump, many complicated calculations by the ship's computers are neccesary to avoid 'missing the mark', thereby getting stuck in Jumpspace, to avoid leaving Jumpspace to late, to make sure energy and light levels are appropiate, as to avoid exploding, and to avoid accidentally jumping inside an object within Jumpsapce.. In fact, even entering Jumpspace to begin with takes a fair amount of computational power. Apart from that, great amounts of energy are neccesary to power the Projector. Most ships can also only afford to stay within Jumpspace for a fairly short amount of time, neccesating regular stops in nearby systems before continuing ones journey. As such, this form of jump-travel is often slow, with longer yourneys taking many months or even years. It also comes with a rather big risk of no landing at the exact target destination, due to the sometimes weird nature of Jumpspace and the strain it already puts on most ships computers to get anywhere near the target destination.

Iterium

"Controlling the iterium is of utmost importance to the continued survival of our State. Without it, we will wither. Our ships will be lost in the ocean of space, we will be unable to efficiently contact our settlements, and our many enemies will be able to move against us. Faster, more organised, safer. With iterium, however, we can safeguard our people, and control this galaxy." -Overseer Qetanak in 'A General Essay on the Future of Directorate'

Iterium is a form of exotic matter found around some black holes. It is relatively rare, and highly priced within Known Space and likely beyond for its strange properties and effects on Jumpspace. Iterium is created from the interaction between certain blackholes and Jumpspace, resulting in the creation of the material. These blackholes, commonly known as iterium blackholes, are among the most contested systems in Known Space. Iterium often takes on a similar role to oil in galactic economics and politics, with iterium blackholes being the oil wells. Iterium looks not entirely dessimilar to mercury. In its natural form, the material looks like a metal-like liquid. It 'reflects' everything i nits surroudnings, but appears to break and bend light in various ways, making reflections look almost broken. If a light is shined on it, the rays will be reflected in almost unpredictable manners, not entirely unlike a prisma. The material is also usually 'floating', it appears to be naturally repelled by most other matter, to the point that it ends up floating a few centimetres or so above the ground and away from any potential walls. If not encases, iterium will often simply float across rooms and the like, sometimes even changing the hight at which it floats. If one were to try to grab or touch it, the material would simply move around and away from the individual. Iterium does not seem to go through the ordinary states of matter, with it being impossible to heat it to a gas or cool it down into a solid state. It is possible to refine it, however, in which case it becomes slightly more solid like, becoming not entirely unlike a crystal. In its crystalline form, iterium is still repelled by most other forms of matter, though less so. It floats less high, and it is possible to, with some effort, grasp and hold it. It will still 'drip' dropling of itself occasioanlly, and can, quite easily, be divided into more semi-solid crystals. In its raw form iterium has little industrial uses, though it is also not entirely useless either. The material can be crystalised by exposing it to various electric currents, and will in fact use its refined form if not regularly 'repolarised'. Iterium also has a certain 'immunity' from gravity. Whilst it is affected by gravity, it is much less so than it should be, based on its mass.
As previously mentioned, iterium has various effects on Jumpspace. In its raw form, it always reads as a strange 'anomaly' on sensors inside Jumpspace. This is how most civilisiations end up discovering it. Iterium has a strange relation with electricty, with various electrical 'frequencies' and currents having various effects on it (such as, as previously mentioned, refining it). If exposed to the right current, the 'anomaly' iterium produces will grow bigger and more noticable, acting as a sort of primitive communication device or as a beacon. It is a common method of sending out sos signals within Known Space. This, however, is the only useful effect raw iterium can reliably produce. Whilst it can produce some other qualities, it is often highly unstable when doing so, sometimes leading to explosions or lethal anomalies. Refined iterium (also known as iterium crystals), on the other hand, can very reliably produce a great many of effects. For an example, it can be used to make jumpfields significantly larger, or to communicate faster than light. Most alternative forms of ftl use iterium crystals in one way or another, explaining why they are so important.

Iterium Mining

As iterium naturally occurs around blackholes, mining it is not always easy. Luckily, certain frequencies of electricity work on it in a similar way to a magnet on metal. In other words, iterium mining consists of stations in orbit of iterium blackholes shooting electricty inside the event horizon and then waiting untill it is 'mined' out. Most iterium blackholes have more than significant iterium deposits, though it is possible for a blackhole to 'run dry'. In that scenario, it will likely have regenerated its deposits in a few centuries, maybe a few millenia. It is currently unkown what makes certain blackholes iterium blackoles, and the material is usually searched out by simply scanning for its anamolous readings inside Jumpspace. Some civilisiations also use force fields alongside the 'electrical beam' to mine iterium, as it prevents the material from 'falling back' into the blackhole (the electrical beam method usually only creates a somewhat slim amount of iterium, as most of it is either unable to escape the blackholes gravity or is sucked back into it). The forcefield thusly creates a sort of 'funnel' for the iterium to run through.

Iterium Communication

"Often, I marvel at the ingenuity of those of the stars. At what is possible in the universe. We only discovered light was the fastest thing there is maybe a century ago, and now we are told that we were wrong. One can travel, talk or hear faster than light. One can be teached to do so as well. The universe is an oppurtunity, and we are given all the tools to use it"

Scientist Xta-Mkarit, shortly after first contact and the beginning of uplift protocol by the Commonwealth of Stars

It is possible to use iterium crystals to communicate faster than light using so-called 'iterium signals'. This is done by a device known as a communication station (or comstation, for short). It esentially 'converts' digital data (usually from either radio or digital transmissions) into iterium signals which travel through Jumpspace, by exposing the crystal to various electrical charges. This works like a sort of binary, or morse code. Exposing the crystal to the charge for a certain period, then stopping, and then exposing it again, thereby creating long and short messages. All relays also come with an iterium detection device, using a second, slightly modified crystal that 'picks' iterium signals 'up'. It essentially reacts in various ways to iterium signals passing near its Realspace location in Jumpspace, these reactions are then interpretated by a computer to decrypt the actual message. Commstations are somewhat expensive to make, due to needing two iterium crystals, and are as such rarely used for planetside communications, as radio and similar systems are already more than efficient enough. Most planets and stations do have access to at least one comstation ,sometimes shared with other planets or stations, which simply picks up their radio transmissions. Whilst most comstations are fully automated (only seeing a maintenance crew every year or so, and 'recharging' their crystals themselves), some of the largest ones that get millions of messages daily do have a small crew tending to them. Those 'communication relays' tend to be essential to the communications of entire sectors, and are often among the first targets in an invasion because of this. Due to the shear amont of messages traveling through Known Space at any time, most iterium communications are labelled with a category and importance code, in addition to an intended reciever and the sender. Most commstations will automatically read those codes,and act based on them. Iterium signals have an, by astronomic standards, relatively short range of a few lightyears or so. As such, most star systems will have at least one. It is also impossible to send iterium signals through Jump Barriers, adding to the suspicions that the Barriers might be artifiicial in nature. It is possible to jam iterium communications by simply causing massive ammounts of interference, though this is an expansive and hard to pull of method as one would need a great ammount of message relays in one system for it to work, and it also cuts of one's own communications. Iterium messages are relatively slow, with it sometimes taking a day or two or so for messages to arrive if the distance is great enough. Whilst iterium commstations only need a small crystal, bigger crystals do provide more powerful signals, which have a greater radius.
It is also possible to use iterium signals as a form of ftl radar, though it is relatively crude and only works on objects within Jumpspace. There is no known way to detect objects within Realspace over astronomical distances.
Most civilisations discover iterium communications very soon after discovering iterium itself. The technology is more than a staple of Known Space, and is utilised by almost every single spacefaring civilisation except the youngest ones of them.

Travel Nexi

"Just like our ancestors tamed the savage wilds with roads, so too have we tamed reality itself with our own network of safety" -Banath Eekon, researcher upon the Bathori discovery of Travel Nexus technology

As Basic Jump-Travel is somewhat dangerous and unreliable, most civilisiations eventually resort to using so-called Travel-Nexuses. A Travel-Nexus is essentially a station with a supercomputer and a massive Jump-Projector inside it Most Nexuses also use iterium crystals to boost the size and potency of their Jumpfields. Finally, every Nexus has its own way of artificially, and quickly accelarating ships to make their Jumps possible and cheaper. Most usually, this is some form of laser pushing the ship to the right accelaration. In other words, if a Basic jump is like jumping, a Travel-Nexus jump is like being (safely) shot out of a cannon. This makes ftl travel much quicker, safer, and cheaper. Civilian ships no longer need their own projectors, as they only really need to travel across established routes. Instead of jumping across every system, and then recharching after a few dozen jumps for a day or so. they can instantly jump again after arriving by their pitstop's system Nexus. Because of the stations hyper-specialised supercomputers making the calculation for the ship's jump (and also the jump happening across pre-determined paths) there is much less of a chance to arrive in a 'wrong destination' within Realspace, or to accidentally fly into gravity fields. Finally, because of the more potent Jump-Projectors and the more efficient ways of accelerating, ships can more easily penetrate higher layers of Jumpspace, therefore going significantly faster.
Most Travel-Nexuses go across establishes 'lanes', the so-called starlanes. Their computers are, for the sake of maximum efficiency, specialised to a few connections. They are also placed in such a way to optimally connect to the intended Nexuses. As such, starlanes are often called the highways of the galaxy, with thousands of ships travelling by them every day, and with most of space infrastructure, such as deep-space ports (which often also come with 'hotels' and entertainment facilities) and commstations (or comm-relays), being positioned across them. Most starlanes are also patrolled by military ships, to crack down on piracy, other forms of crime and potential invasions. In war, securing the right starlanes is often a primary concern. Most systems are connected to aproximately 2-3 notable starlanes, and then some smaller, sectorial ones. Though, it is to be noted that the truly essential starlanes, the ones that connect major trade areas and the like, tend to only be tangentially connected to non-essential systems. Some systems can be connected to asmany as 5 notable lanes, or 3 major ones or something of that nature,and as such, often become important trade hubs. On the other hand, there are also stationswith only one connection to the greater network, often deliberately so for strategic reasons.
Some civilisaitions have also taken to creating 'Nexus-Ships' wich essentially just act as mobile Travel-Nexuses. This approach is mostly popular amongst fully nomadic civilisiations, and civilisiations like the Czarkix Hordes. Most nations don't use such devices, as they are more expensive than Travel-Nexus stations, and make for a too obvious weakpoint in military encounters. Many civilisiations do have some form of 'Jump-Ship' which has a bigger and more efficient Jump-Projector, but is still a normal military ship and is usually not the only ship with such a projector. These are usually worse than Travel-Nexuses, but better than ordinary Jumps.

Other Faster-Than Light Methods

"It's a big universe out there, and we understand so, so little. Who knows what others have known? What is possible? What has been done, and what has yet to be done?" -Katanata Ikton, captain of the People's Revoluition

Though the aforementioned FTL methods are the biggest and most common ones in the galaxy, some factions have discovered other ways to use Jumpspace in order to travel faster than light. Some of said methods will be listed here.

Jump-Vortex

The Jump-Vortex is an iterium technology, to which currently only the Empire of the Path knows the secret to. It is effectively a station which, using iterium crystals and some other devices, is capable of manipulating jumpspace in such a way that it can create a 'vortex' of some kind. This vortex is able to 'suck' ships in, allowing ships to both arrive faster inside a system, and be more precise with where they re-emerge from Jumpspace. It is also common conduct for the Empire to place a so-called 'Vortex Station' in an enemy system in times of war to serve as an easy launching point for an invasion. On top of this, the technology can be used to set ambushes or traps for enemy ships traveling through Jumpspace. The Vortex-Station can also be set to have a 'reverse direction', pushing ships away from it, instead of towards it. Though this does cost more energy than pulling ships in. This allows the users to both gain a notable speed-boost, as they are 'pushed away' from the station, and to make it significantly harder for enemy ships to enter certain systems. The Vortex has no effect on iterium signals. The technology has, so far, been a major contributor to the Empire of the Path's current position in galactic politics, as the most powerful nation of Known Space.