One reason to explain is when the addition adds to the story. The problem then is deciding what is worth explaining, and if it is, how to do it? An explanation is different from a description, which involves “what it is”, while an explanation involves “why it is like that”. Somewhere intermediate are the answers to the “how” questions. “What it is” may be necessary to follow the story, but “how it works” is different. In my opinion, it only matters when something else follows. If this can be pulled off, a far more enriched texture follows.
In my latest ebook, Red Gold, the background involves the colonization of Mars, which requires large-scale space ships to get there, since the plot also requires starting on Earth. To get artificial gravity, these are giant rotating disks. Now, we could merely have rotating disks, but look what happens if you think about how they rotate. First, there must be a means by which they can rotate while having motors that direct the direction of travel. That is most easily achieved (in fiction, if not in reality) if the motors are separate from the disk and joined in some way to something that does not rotate. These requirements give rise to a description that, while quite speculative and open to a lot of criticism, at least has the virtue of painting a more detailed picture that I hope makes the written section more plausible. How to do this? I had the disk spinning about the non-rotating support, and within this there is a massive inner hub that spun at extreme velocity in the other direction. For those in the know, when spinning something up, somehow you have to conserve angular momentum. It would be easier in some ways to have the counter-spinning part external to the disk, but that would make the stabilization of the motor mount near impossible. What I hoped to achieve with this detail that is not needed for the story is to give the reader a better feeling of “being there”.
However, the real point is that having reached this “design” more detail can be added. The disks carry plants so it is important that they travel through space “face-on” so as to maximize the collection of sunlight, but they have to land “edge-on” or “bottom down” so the motors have to be able to be re-oriented. Finally, the motors have a mass of about 25,000 tonne, so there has to be a means of separating them from the disk prior to landing, otherwise the supports would collapse and the motors would crush the ship. That means the disks have to land essentially unpowered.
Once that is done, I felt it was important to use those descriptions to aid the plot. Thus the danger of the landing permits one protagonist to get down before anybody else, and this allows the build-up of tension between two men who are falling out. The structure also permitted the invention of a ball game that is rather difficult to play. There are two major protagonists who start off as business partners (more or less). This game was used to bring to the open that one was sexually involved with the other’s wife, and it was also used to have a game between the two protagonists, and when one is shown to be a bad loser, the rift between them starts to open, which is a major advance to the plot. The design gives a great excuse to get the ship to land in the “wrong” place, at least as far as one protagonist is concerned, and it forces several other things to happen that otherwise should not have. So, while it may seem unnecessary to have such a detailed discussion of ship design, I hope it gives a clear picture to the reader, and as the book continues, the specific design permits several pieces of plot development. Rightly or wrongly, I feel that when the plot depends on the descriptions, then everything hangs together better. What do you think? If you wish to form your own opinion, the ebook has a free download from Amazon on November 16-18.