"What is subspace?" According to the Encyclopedia, it is a continuum with different laws than our own. That doesn't help much, considering you can makes fields of it in our universe. The best explanation I can come up with is that subspace is the "substrate" within which our universe exists. A subspace field is either a forced or natural intrusion of this domain into our own space, altering the behavior of things within our space-time. The "subspace barrier" is the albeit flimsy dividing line between the two continuums. Many things support this: in TNG "Schisms" creatures exist within a tertiary subspace manifold, a manifold being a term used to describe the form our own universe takes when viewed from a higher (theoretical) dimension. This is also called a deeper level of subspace; another universe which is connected to ours by subspace. In TNG "Remember Me" an entirely new universe was "spawned off" by a static warp bubble, and it was only accessible through subspace. The proto-universe in DS9 "Playing God" was an intense subspace manifestation as well. Protrusions of subspace, such as in TNG "Force of Nature", DS9 "Vortex", or the shock wave in Star Trek VI: The Undiscovered Country do nasty things to our space-time. But subspace is also everywhere: sensors can detect subspace distortions caused by normal objects (TNG "Descent"), communications work through subspace, and you can create subspace fields. Whenever our space-time is distorted or torn, or large amounts of energy released (explosions) there are subspace effects; wormholes and Transwarp Conduits are good examples where subspace plays a part in the effect, and the presumably material-based explosion of Praxis in ST6 generated the subspace shock wave. Subspace fields are intentional manifestations of subspace in our space-time, caused by the controlled release of energy in a warp field coil. These fields have many effects, often depending on the intensity. * They leave subspace distortions behind (TNG "Interface", DS9 "The Maquis") even when they're gone. * An object placed in a subspace field has a reduced inertial mass relative to things outside the field. (TNG "Déjà Q") * A symmetrical field (aka "Warp bubble") with enough power can create an entirely new universe, but it may not be stable. (TNG "Remember Me") * An asymmetrical field can propel the generating ship at the speed of light; nested fields propel the ship at the speed of light relative to the field beyond. (TM) * A subspace Soliton wave can carry a ship at the propagation speed of the wave. (TNG "New Ground") * A field can be embedded in an object (TNG "Phantasms") * Overlapping static warp shells can create an artificial subspace barrier in a localized region of space-time (TNG "All Good Things...") You can think of subspace as being the "medium" in which our space-time exists. The nearest parts (nearest being measured by the energy it takes to access them) are tightly coupled to our own universe, and can be thought of as being mapped to our space-time. This is what sensors generally read, and what the subspace fields of warp drive are interacting with. Slightly deeper parts can connect points in our universe to others. Wormholes and Transwarp Conduits are this sort of thing. Deeper still are the "untamed wilds" seen in "Force of Nature". And even further down are entirely separate universes, all held together by subspace. Subspace is not in an alternate reality, or "place", or space-time where things go - or at least, they don't go in the world of Star Trek. It is not entered by a starship at warp. A ship creates a subspace field which acts like another universe very tightly coupled to our own. If I was inside such a field and you were outside, we could conduct a conversation, shake hands, etc. But when the field is powerful enough (1000 millicochranes or more) and asymmetric, it is propulsive. Nested, de coupling fields magnify the effect considerably. But the ship still interacts with everything in our universe, and vice versa, as the level of subspace in which the field exists is so tightly coupled to our own that it appears no "fancier" than, say, a magnetic field, if you're looking closely at it. The weakest subspace fields do appear very similar to traditional fields, like magnetic fields. They have associated particles (see below), can be bound to objects (TNG "Phantasms"), can be used for transmissions (subspace radio), and generally unremarkable on their own other than as residue from more powerful effects. To keep Jason Hinson and General Relativity happy, subspace doesn't need to follow the rules of relativity. Subspace might have a unique reference frame, and everything enclosed in a subspace field has the reference frame of subspace. "What are Tetryons and Verterons?" Subatomic particles mentioned in TNG "Force of Nature", and a number of other episodes. These seem to be some of the particles associated with subspace fields, just as photons are particles associated with electromagnetic fields. A verteron mine is used to disable the Flemming, a Ferengi ship, and the Enterprise in "Force of Nature". Verterons somehow manage to break all devices which use subspace. Simplest explanation - they inhibit interactions with subspace, causing massive overloads and feedback which damages equipment. Picard suggests using them to mask a subspace resonance signature in TNG "The Pegasus", although Data points out that their artificial nature would preclude their use in that circumstance - masking a warp core for several hours. Verterons also infest the Wormhole near Bajor. In DS9 "Playing God", a proto-universe intruding into our own c/o subspace was kept contained by an energy field, but verteron pockets in the Wormhole threatened to release it, destroying a Runabout and perhaps even the Wormhole. Verterons and subspace do not mix well. They also allow vessels to travel through the wormhole under impulse power (DS9 "In the Hands of the Prophets"), and they appear in a display in Keiko's classroom on DS9 as the verteron membrane at the outer boundary of one side of the wormhole. Tetryons are particles which are stable in subspace but unstable in normal space. They appear to be the main mediating particles of subspace interactions with normal space. They were introduced in TNG "Schisms" but they've shown up in TNG "Force of Nature", and a tetryon field is the result of an metaphasic shield interaction in TNG "Suspicions". "Why do ships always meet the same way up?" I know it's been proposed as a joke, but the idea that warp travel requires a universal "up" isn't as silly as you might think. We know that things in normal space affect subspace. What if the mass and orientation of the entire galaxy, which is nothing to sneeze at, affect subspace in such a way as to make travel more efficient if your warp fields are generated parallel to the plane of the galaxy? It's then more efficient for ships to align their warp drives with the plane of the galaxy, so flying "up" and "down" in the galactic plane (which is relatively thin, about 1/10th to 1/40th the diameter of the galaxy) would take more energy. This also explains the banking into turns and such. If you have galactic-up and galactic-down to choose from, why always the same way up? Probably a matter of protocol. Only "loser" races don't adhere to the standard. You'll also note that many small ships are vertically symmetrical, perhaps as their designers aren't quite up to snuff when it comes to designing warp drives. The second is that the subspace field of the galaxy would do really weird things at the edge and at the center. Remember the Great Barrier of TOS fame ("Where No Man Has Gone Before" and "By Any Other Name") does nasty things to the Enterprise, and the one near the center of the galaxy (if you believe in Star Trek V) was pretty scary too. Kirk made a number of references in TOS "By Any Other Name" about warp drive not working outside the galaxy, or something to that effect. While the Kelvans of Andromeda had got that licked, this does give the theory a little bit of support. Another note: the subspace shock wave seen in Star Trek VI was both planar and aligned with the direction of the Excelsior's vertical axis, and shock waves within the subspace rift of TNG "Force of Nature" were also aligned coplanar to the ship. "What is subspace radio?" A means of sending a signal through subspace, so that it is not limited by the speed of light. This is done by creating a subspace distortion which propagates in much the same way as an electromagnetic field. A large amount of energy is needed to send a signal any large distance, and the more energy that is available, the deeper the signal can be forced into subspace. However, the signal dissipates over time, eventually releasing the energy that is left as an electromagnetic field. A more powerful initial signal can travel farther before this happens, but there is a limit; too much energy and the level of subspace that is used won't be tightly coupled to our own space-time any more, and the signal will probably go awry. "How fast is subspace radio?" Under ideal conditions, Warp 9.9997. (TNG TM, page 99) This is "sixty times faster than the fastest starship, either existing or predicted" - assuming traditional warp technology. The Encyclopedia says that with boosters and relays, Warp 9.9999 is the speed, but this may be a typo.