![[Mijars side]](http://www.nvg.ntnu.no/~hao/bilde/up.gif){kind=small}
Knowledge of what actually exists in jumpspace is lacking, since by its very nature it is unmeasurable by n-space instruments. The prevailing theory is that theoretical particles known as tachyons exist in jumpspace, and normal particles familiar to n-space cannot exist. Like normal space, the speed of light is a limiting factor in Jumpspace. Unlike the maximum that it imposes in n-space, in jumpspace the speed of light is the minimum "at rest" speed a particle can possess. Most particles in jumpspace are at a speed that can only be described as infinite.
There are several dimensions, or quantum levels, of jumpspace. All known dimensions appear to be two-dimensional in structure, roughly corresponding to the n-space galactic plane. Part of our normal space-time continuum (n-space) within about 25 light-years of the galactic plane is somehow connected through the jumpspace-time continuum (j-space). Normal space locations are connected through jumpspace dimensions as if the z-axis of the galaxy didn't exist.
Current data seems to indicate that the topography of jumpspace is non-uniform. The amount of n-space connected through jumpspace perpendicular to the galactic plane is greatest near the core, and attenuates as one moves towards the galactic rim. It has also been shown that gravitational disturbances "warp" jumpspace. This non-uniformity due to gravitational disturbances is the cause of misjumps near gravitational wells. If the gravitational disturbance is large enough, it creates its own localized jumpspace dimensions, effectively cutting off local n-space from the galactic jumpspace plane used for interstellar travel.
Very few races have independently invented a method of using the jumpspace phenomenon for interstellar travel. In fact, one modern hypothesis now being hotly debated is whether any of the "Major" races have invented the Jump Drive at all! This hypothesis asserts that only the Ancients independently invented the Jump Drive and it was they who "seeded" relics for modern races to discover. Proponents of this theory argue that a scientific Theory of Jumpspace is still in its infancy, and nowhere near the level required to invent a method to traverse jumpspace. Opponents of the Ancient Seeding Hypothesis retort that one doesn't need a Theory of Thermodynamics to boil water--sometimes Humaniti just gets lucky.
In any event, in spite of some Psionicists assertions to the contrary, the Jump Drive is the only known reliable method of interstellar travel.