I was talking over my last post about the 'gravity train' explanation of Jump Space with Raymond McVay and realized that is was scary as hell on some levels. Imagine our entire Universe is just a thin skin over a hyperdimensional otherspace. The unknowable is also right behind you. Also in front of you and on all the othersides, just rotated a scant 90 degrees from your comfortable native three space.
If there is a force that is analogous to gravity in this realm are there other forces like a repulsive force allowing the Universe to keep its shape (or keep expanding). Are there currents in it responsible for the occasional misjump?
Are there 'solid' bodies? What are they composed of? This could lead to all kinds of fun. A ship in Jump precipitates out when it reaches the Jump Limit. So would an asteroid or planet sized mass. Imagine another moon composed of mirror matter or negative matter suddenly popping into reality 800,000 km from Earth.
At the very least sections of the Underspace must vary in density because jumps do not all take exactly the same time. What causes those and what else could it cause? Moreover, can human technology cause them to cut down jump time? Is it a good idea?
Jumps currently are from point to point in our Universe and seem to consist of a relatively shallow dive into Underspace. What if a ship just descends deeper into it using and then uses its fuel to return to the departure point. Are lower regions different in characteristics?
Does anyone live there?
In my Ghost Drive seting ... yes! The NBEs seem to be native to the Underspace. Sometimes they make the leap to our Universe where they are harnessed for their useful talents like moving ships without using rockets. What else lives there?
Humanity has a long tradition of using technology it does not fully understand with unexpected fallout. This was literally the case when the atomic bomb was used on Nagasaki and Hiroshima. Radiation proved far more horrific than the initial casualties from the blasts. But there are many other examples. Poking the unknown with a short stick is part of being human.
What happens when the unknown pokes back?