FTL Mechanics (Synopsis)

This is a Synopsis page! Expect heavy summarization of complex topics and writing from an OOC perspective

While the articles on Ideal Semispatial mechanics and Exospace Node Theory provide a lot of information on the state of the PCG-verse's FTL mechanics and how they fit in its history, they're also quite diluted with lore and don't provide all the info they need to provide a comprehensive overview of the PCG-verse's FTL technology to the average person. This page is designed to rectify the issue by listing all the relevant information clearly in one place, with the others being there mainly for lore/in-depth explanations.

## Exospace

Without going too in-depth, Exospace is a catch-all term for two groups of four dimensions, subspace and hyperspace (see below)― as opposed to realspace, our standard three dimensions. Both hyperspace and subspace are divided into 24 sections, varyingly called levels, planes, energy layers, or strata. Each strata is independent of the others, such that the "terrain" of a given layer may be completely different from one to the next. These strata are often described in terms of depth, such that the first strata is is the shallowest and the 24th is the deepest.

Each of these strata is itself comprised of "patches", which are roughly analogous to an organic cell. Every patch is mutually link with another, often more than lightyears away, with which it is said to "interact" (in-universe lingo to say they can exchange particles directly between each other). Adjacent patches can also interact, though much more weakly (particles transfer much slower).

### Subspace vs Hyperspace

For our purposes, however, this is largely where the similarities between subspace and hyperspace end― in terms of the numerous other trends found among hyperspace strata, hyperspace and subspace tend to act oppositely to each other. Thus, deeper hyperspace strata tend to vastly increase in ambient energy, less-accessible and shorter-lived Phasic Nodes, and decreased distance between coordinates relative to realspace (see Coordinate Mapping, below); deeper subspace strata, on the other hand, feature have vastly decreasing ambient energy, more-accessible and longer-lived Phasic Nodes, and increased distances between coordinates.

In terms of travel, the rule of thumb is is that traveling through a hyperspace layer is faster and stealthier than using the equivalent subspace layer, whereas the subspace layer is easier to navigate and much more difficult to interdict.

### Plane Labeling

Methods that give names to specific exospace strata are called plane labeling systems; two such systems are used in-universe, as well as most wiki articles regarding exospace/FTL drives (this one included).

The first (called the "T'pak-Al'koth system" in-universe) assigns each strata a Greek letter, starting at alpha (shallowest) and ending with omega (deepest); for differentiation, uppercase letters are used for hyperspace strata and lowercase letter for subspace. Thus, the first/shallowest hyperspace strata is designated Α, followed by Β, then Γ, etc.― all the way up to the deepest hyperspace layer, Ω. Likewise, the first/shallowest subspace strata would be designated α, then β, γ, etc.― all the way to ω.

The second system, the se'Poi system, is similar to T'pak-Al'koth with numbers instead of letters. Every strata is assigned a number (called a se'Poi number, represented as k) from k = 1 (shallowest) through k = 24 (deepest); for differentiation, hyperspace strata are positive and subspace strata are negative. Thus, k = 1 is equal to A, k = 2 equals B, all the way up to k = 24 equating to Ω; meanwhile, k = -1 is equal to α, k = -2 equals β, etc.

### Coordinate Mapping (Realspace vs. Exospace)

Despite being fundamentally four-dimensional, exospace coordinates do possess an almost one-to-one correspondence with three-dimensional realspace coordinates― with the exception of so-called "tachyonic rifts", which result in a large discrepancy between the two.

While their relative position is mostly the same, however, their relative "distance" does not: increasing hyperspace layers tend to decrease distance between points more-or-less proportionately, whereas subspace tends to increase them.

### Exospace "Terrain"

Though somewhat of a misnomer, interstellar cartographers and travelers will often refer to exospace having "terrain". Obviously, this is space, so there's no real terrain of any literal description; that is not to say, however, that all areas of exospace are created equal. Some exospace patches are easier to travel through than others, resulting in fluctuations in speed; as a result, there is somewhat of a "speed gradient", where some areas of space are faster to travel through than others.

However, this gradient is gradual (physics reasons prevent any one patch from deviating too much from nearby ones) and generally not very significant (maybe adding on a few hours on a few-days voyage). Most of what we would think of as exospace's terrain comes from a large group of energetic, disruptive or poorly processes within patches that result in various varieties of "storms" (tachyon storms, verteron storms, exotron storms... use your imagination =P). Additionally, large gravity wells (planets, stars, and the like) can cause disruptions in exospace, slowing nearby ships (if not ejecting them into realspace entirely).

A critical thought to keep in mind: exospace is by no means static. It moves and flows, almost like an ocean; a comparison to a tamer version of the warp from Warhammer 40K would not be entirely amiss, sans the evil gods/demons/cultists (and of an entirely-different composition...). I'd posit the spacefaring powers would probably maintain a fleet of monitoring beacons/probes to analyze this ebb and flow of exospace in real-ish time. Again, be creative with applications/storytelling. ;)

#### Phasic Nodes

Phasic nodes were the concept from which the original FTL unification project was based. For all practical purposes, they essentially act as highways, allowing ships within them to travel markedly faster than ships traveling outside them. They are generally more stable than the surrounding areas of exospace, to the point where some deeper hyperspace strata can only be entered within one. Like patches, every Phasic node occupies only one exospace strata.

As stated above, the accessibility and lifespan of a Phasic node varies inversely with it's strata's se'Poi number: deeper subspace nodes last anywhere between tens of thousands or to potentially billions of years, are extremely stable, and can be entered from virtually any point; shallower hyperspace and subspace nodes can last from anywhere between tens of millennia and a few centuries, are fairly stable, and can be entered from some points along the node (of varying difficulty); and deeper hyperspace nodes last between a handful of centuries to as little as a few hours, and highly unstable, and can only be entered at their entrance and exit points. Keep in mind, these are more guidelines than rules― should conditions be right, deeper subspace nodes can last a little as a few weeks, while deeper hyperspace nodes can last for nearly a millennium, etc.

## Applications

### FTL Drives

One of the first and arguably most important development to come out of the study of exospace is faster-than-light propulsion. Although Special Relativity forbids objects with positive mass to move at or faster than the speed of light, this only applies to the three spatial dimensions that comprise realspace; Ideal Semispatial Mechanics (AKA Corralynian Exospace Mechanics) predicts that there is no such limit on the rate at which exospace intervals can be crossed. As a result, the ban on traveling at certain velocities can be circumvented by entering exospace, traveling to the exospace coordinates corresponding to the realspace location, and reverting to realspace― effectively achieving apparent velocities higher than *c* without breaking any laws of physics.

This ability to exceed the speed of light has obvious utility, virtually single-handedly enabling the creation of the modern galactic political and social system. Much as the internet, industrialization, and fire all revolutionized their respective time periods, so too has FTL technology defined ours.

#### Static vs Transitional

Most conventional FTL drives fall into one or two categories: Transitional drive systems or Static drives systems or.

Transitional drive systems operate quite simply: they use what's called a warp field or warp bubble to stress the fabric of spacetime until it tears, allowing the ship to slip into the shallowest layer of either subspace or hyperspace. If the drive is sufficiently powerful, it can then begin to move upwards to higher strata. Higher energy layers allow for much greater increases in speed, but are highly taxing on a ship's FTL drive and energy reserves.

Static drives were first developed intentionally to provide an alternative to this intensive process. Through various methods, Static drives skip any intervening energy layers entirely and enter the desired plane directly. Because they do not need to worry about wasting energy changing energy layers ―even moving down strata is usually impossible, much less up― static drives can often reach much deeper strata; however, they are also usually less flexible and energy-efficient than their transitional equivalents.

##### **In Summary (AKA tl;dr)**

* Static: Directly moves to desired plane; faster
* Transitional: Moves through each layer in sequence; more flexible and energy-efficient

#### Corralyn's Law

Arguably the most important development to emerge from Ideal Semispatial Mechnaics is Corralyn's law: vapp = 10Ж \* *c*. While simple, this law is of vital importance: it allows fairly-accurate estimation of the apparent velocity of a ship traveling within exospace, before the exospace speed gradient, detours, phasic nodes, etc. Basically, it allows you to directly convert lower and medium warp factors into velocity (higher warp factors begin to exceed the predicted speeds by significant margins).

For those of you who prefer to use the ly/hr unit, there is a modified version of the equation which will work for that unit: vapp = 9.133 \* (10-12 + Ж) ly/d (its approximate equivalent).

#### Warp Bubbles

As stated previously, all conventional FTL drives use warp bubbles to stress spacetime in order to enter exospace and achieve apparent-FTL flight. If a ship's warp bubble is disrupted, it will be (sometimes violently) thrown back into realspace― hence the rise of modern interdictors and warp scramblers. Contained within a warp bubble is a small pocket of realspace, containing the ship and any other realspace objects within the field's radius. If the warp bubbles of two vessels overlap, their pockets will merge, allowing them to interact as if they were in realspace.

The real reason warp bubbles get their own section, however, is because of the Arcite-Summins Effect, which states that *all eccentric stress fields are innately propulsive within a semispatial matrix*― in other words, non-circular warp fields propel themselves, along with any objects inside of them. In fact, this propulsive effect is much more efficient than traditional propulsion methods within exospace, to the point where spherical warp fields have become the hallmark of less-advanced species. The problem with this is that non-spherical warp fields are also much less stable, making them more difficult and energy-intensive to maintain; the tremendous speed boost is more than worth the price, however.

## Notes

1. ↑ These dimensions are sometimes referred to as "sets"― Set 1 is hyperspace, Set 2 is realspace, Set 3 is subspace.
2. ↑ By this convention, realspace is usually represented by either the Hebrew letter aleph (א).
3. ↑ Realspace is generally understood to be k = 0.
4. ↑ Though not officially referred to as such, warp factors could be considered a third type of plane labeling system. Warp factors are absolute value of a vessel se'Poi number, and are commonly used on vessels with transitional drives.
5. ↑ Due to reasons listed below, this is much more pronounced in hyperspace than subspace― though, in term of frequency, it affects both equally.
6. ↑ Because they do not exist within the three spatial dimensions, objects or places in exospace cannot be described with "distance" per se; however, exospace coordinates do have a property (measured with the unit Qales) which is analogous to realspace distance, and is often used as such.
7. ↑ Note that these groupings are for convenience; in practice, the differences of nodes between strata represents more of a spectrum than a couple of categories.
8. ↑ Technically speaking, there is no limit to the maximum apparently velocity attainable in a given layer— in other words, planes don't actually have upper speed caps. However, due to the enormous amounts of handwavium contained within exospace, one eventually reaches a point of drastically-diminishing returns, making it far more economical to simply move up a layer.
9. ↑ where vapp is apparent velocity, Ж is warp factor, and *c* is the speed of light

## See Also

* Original FTL unification system, for archival purposes
* Ideal Semispatial Mechanics, in-depth technical explanation of the basic operation of FTL drives
* Exospace Node Theory, the in-universe theory behind modern FTL travel

* List of FTL Drives (WIP)
* FTL Drive infobox