I've been looking into making my own campaign for awhile and the one thing I wanted to develop more was the nature of subspace and nodes. For something that is absolutely essential to the freespace lore, not much is said about it. So I made a little write up on the nature of subspace, and wanted to see what everyone else thought of it. It's kinda put into a question and answer format, and answered like an episode of The Universe in 2367. So, tell me what you think of it. (And before anyone crucifies me on this part, I am not happy with the "Node Travel Time" section because I think the Subspace article on the freespace wiki is off with that number of 1 lightyear per min. because I'm pretty sure Delta Serpentis is about 210 lightyears from us. Possibly 10 lightyears per min.) Anyways, enjoy... or at least I hope you will.
Why do ships drop out of subspace quite a distance from a subspace node to use it?
There are several reasons for this. First off, intra-system jumps take power. Inter-system jumps take a massive amount of power. Ships need to charge up for the use of an inter-system jump drive before they reach a jump node. Secondly, nodes have what is known as a Subspace Ripple around them. This is a natural effect of the node that interferes with matter travelling through subspace near it's focal point. Therefore, a ship passing a node in subspace would "fly over" it's point in subspace as if it were not there to begin with. Similar to how Earth's magnetic field pushes cosmic radiation around it. Some clever navigators have been able to push this threshold to exit subspace close to a node, but it is impossible for a ship to exit subspace directly on a node; if pulled out of subspace too late the ship would be pushed over the node and exit on the opposite side facing the wrong direction. Also, a ship may never enter a inter-system node via intra-system subspace travel, due to the fact that the frequencies of subspace are different between subspace space travel and node travel. In theory, matter can travel from subspace to a node subspace route, but the energies required would reduce that matter to elementary particles during the transition. The last, and most simplisitc reason, for a ship to drop out of subspace a kilometer or more from the jump node is traffic. Nodes are a focal point for all ships entering and exiting a system. The chances of a collision from a ship entering or exiting too close jumps up considerable in higher populated systems.
How are subspace nodes formed?
Inter-system nodes are focal points of subspace, allowing travel to other systems. Nodes are formed every second in nearly every part of space, but they are so infinitely small and short lived that even a particle the size and speed of an electron could not pass through the size of the node, and in time before the node decays; if it were at the correct n-dimensional frequency of course. Nodes tend to form around large stellar masses, where gravity is prevelant and connect to another large mass. It is now commonly believed that dark matter and dark energy also are in direct relation to subspace. The best description is that subspace is like a thunderstorm. Lightning seeks out the path of least resistance and strikes, but imagine this strike stayed active for a long period of time, and you could travel on it at a high speed. Nodes work very similarly to this; however, with no relation to electro-magnetic forces, but instead with the forces of gravity. A weak point in the fabric of subspace between two stars connects a tunnel between the two objects for a time (depending on the stability of a node). Predicting where and when a node is formed is one million times harder than trying to predict where lightning will strike. There have been no nodes found in empty space, so it is believed that only stars have enough stellar mass to attract these nodes. Even in a nebula, the stellar remnant Neutron Star had enough mass to hold a node. The probability of a node forming will depend on the proximity between objects, the amount of mass in each system, the amount of dark matter in each system, and the 'density' of subspace. Other than that, it is quite random, at least to our observations with current technology.
Does Travel through subspace occur naturally?
Theoretically, yes. Inside a blackhole the intense forces at work cause some matter to 'leak' through subspace and exit as energy. This is known as Hawking Radiation. A black hole slowly "evaporates" over a vast amount of time, and it is hypothetical that this energy escapes through subspace.
Could an Inter-Galactic Node exist?
It is a possibility; however, it's nearly impossible that a star from one galaxy could connect to another. The node could only be formed around something with incredible mass, like a cluster of super massive black holes located at the center of the galaxy. Unfortunately, with our current technology, our ships could not survive long enough to reach a node here due to the gravitational stresses and the immense radiation at the center of a galaxy.
How long does a trip through subspace take?
Intra-system jumps are near instantaneous due to the relatively short distances involved. With Inter-system nodes, the number actually fluctuates depending on the speed of the ship, the 'compression' of the node, and the distance between the entrance and exit. A ship still "pushes" off of subspace with a propulsion system the same way it would in real space; however, subspace is much more compressed than realspace so the ride seems faster. Even ripples in subspace can temporarily (or in some cases permanetly) change the flow of the node by up to 5% of it's normal value. Most commonly, people average the time to about a light year a minute, but this is only a layman's guesstimation.