Hyperspace

Hyperspace, also known as Slipspace, Warpspace, Subspace, and Otherspace, is a poorly understood dimensional plane utilised by various interstellar civilisations in order to achieve a superluminal method of travel and communication. It is speculated that without the existence of hyperspace, the entire universe would be fundamentally inconsistent with its current self; both in terms of politics and topology.

Theories regarding Hyperspace are rampant in galactic society, with various species hypothesising wildly varied explanations for the function and existence of hyperspace. What is known for sure is that hyperspace is a metastable hyper-compressed multidimensional space separate but concurrent with conventional reality.

While hyperspace may be thought of as being "outside" the universe, both hyperspace and realspace are two contrasting regions of the same structure, and hyperspace must be understood in reference to this; ultimately, it is best described as the part of four-dimensional spacetime that is not realspace in which Faster-Than-Light travel and communication is possible. Notably, hyperspace expresses slightly altered laws of basic physics, although certain core concepts regarding energy transfer and momentum, wave-particle duality, quantum behaviours etc. remain the same.

Mechanics of Hyperspace
Hyperspace exists as a seemingly paradoxical tangle of intertwined higher-spatial dimensions and the natural home of supersymmetric partner particles to everyday ones. It can be best described as - though in a vastly inaccurate oversimplification - as the results of taking the classical "flat sheet" model used to represent the dimensions of spacetime and crumpling it up into a dense, melting ball, thereby creating shorter spaces between points in a method comparably similar to a tightly wadded up piece of paper.

However, while this would be topologically equivalent to the same ‘paper’ stretched out, due to the much higher energies of particles native to it, these particles can tunnel from one part of the surface to an adjacent part and will form temporary manifolds bridging the hitherto separate ‘sides’. The more particles then pass through this bridge, the more it stabilizes and ingrains itself into the topology.

The result of this changing, incomprehensible spatial structure is creating extra dimensions and shorter distances between points, allowing for effectively Faster-Than-Light travel without ever actually breaching the speed of light.

Realspace and this shifting hyperspace are intertwined on a fundamental, coterminous level in a fashion organic minds cannot fully comprehend, despite realspace and hyperspace having significant, measurable effects on one another. Every point in hyperspace corresponds to a point in realspace, both ever unmoving in relation to one another. Although this wound conventionally invalidate the "crumpled, molten ball of spacetime" analogy used to describe the topology of hyperspace, both notions are paradoxically true - further leading to the incomprehensible, alien nature of hyperspace.

It is possible for objects to exist in a 'transitional' phase in which it exists in both realspace and hyperspace. This transitional phenomenon is what allows for hyperspatial communication satellites to exist, allowing galactic communication networks to function and can be observed naturally in super-dense strange matter stars. Despite this, objects that fully exist within realspace and hyperspace are completely intangible to one another - were a ship travelling through hyperspace to pass through the mass of a realspace planetary body, no collision would occur: though were the ship to attempt to transition from hyperspace to realspace while their volumes overlapped, in violation of the Pauli exclusion principle, the results would be invariably messy, energetic and fatal to anything nearby.

Superluminal Travel
The primary purpose of attempting to enter hyperspace - achieved using a hyperdrive - is for Faster-Than-Light travel and communication. Entry into hyperspace itself can affect the speed in which a ship travels through the dimension. The difference in the sophistication of a hyperdrive's entry method can be described simplistically - though somewhat inaccurately - as the difference between a butcher's knife and a scalpel or, to a more extreme degree, a sledgehammer and a drill. This difference in sophistication is regarded as the primary cause of differences in travel times and accuracy; more refined hyperdrives have considerably less 'drift' than less refined drives.

Travel times and distances are, however, also relative to the realspace distances being traversed; as such, it will always take less time for a hyperdrive to travel one lightyear than that same drive will take to travel four lightyears.

Covenant-designed hyperdrives are noted for travelling at a speed of one lightyear per day. Draknisi Imperium hyperdrives are capable of traversing 1000 lightyears in the same period of time.

The same mechanics to enter hyperspace could be utilised by hyperspace transponders to send signals through hyperspace, allowing for FTL communications and data transfers.

Hypermatter
Hypermatter is a form of matter for which existence within realspace is conventionally impossible. Hypermatter is a superfluid with an effective temperature of absolute zero, which maintains the convoluted geometry of hyperspace against both cosmological inflation and quantum tunnelling from realspace, thus necessitating the usage of a hyperdrive. As hypermatter, and hyperspace in general, has a functional temperature of absolute zero, it makes an excellent medium to radiate heat for ships passing through. Despite lacking the energy to interact with the heat of a ship and absorb the thermal energies of ships, the slightly-altered laws of physics within hyperspace nonetheless allow heat to leak into hyperspace through specialised equipment from realspace, or from any foreign object within hyperspace, after which the thermal radiation will eventually “fall” back somewhere into realspace as background radiation.

Hypermatter particles, colloquially known by a variety of names, including tachyons, after the hypothetical imaginary-mass particles capable of FTL travel, and alternatively as hyperspatial neutron matter, despite not technically being either. Hypermatter particles are themselves capable of FTL travel within hyperspace due to its strange nature, although this property of hypermatter particles is not observed in realspace matter intruding within the dimension during transit.

The effect of coterminous intertwining, when combined with the existence of hypermatter is believed to account for the existence of theoretical dark matter; including the believed gravitational effects of dark matter interacting with normal matter that cannot be explained by accepted theories of gravity unless more matter is present than can be seen. Astronomers have concluded that hypermatter and dark matter are, ultimately, the same substance.

Degenerate Hypermatter is formed in the cores of ultra-dense neutron stars, which are described from within hyperspace as “glowing shadows”, and are used as landmarks in exploratory hyperspace navigation and cartography.

Navigation
Navigating the depths of hyperspace is a confusing, nigh-impossible task for biological beings, and straining even for most powerful computer systems. To compensate for the struggle of traversing hyperspace, advanced navigational computers are required for discovering safe passages to a desired destination. Military vessels are universally equipped with such computers in most cultures, whereas they are lacking in the civilian ships of some.

Established paths through hyperspace, known as hyperlanes, are one of the social constructs used for navigating pre-plotted hyperspace routes. Used by civilian and military craft alike, hyperlanes are the 'interstellar highways' of FTL travel. As they are pre-plotted and stable, traversing a hyperlane does not require the extremely intensive calculations of traversing 'deeper' into hyperspace. Instead, navigational computers needed only to follow a set of instructions to arrive at a wanted destination; although drift of several thousand miles is still possible using such a method, this consistently allows a ship to exit close enough to a star system for standard slower-than-light travel in reasonable timeframes.