Again, continuing the theme of time-keeping in world-building for a fantasy world, I will now turn to the hours that make up a single day. For the record, in the world of Athron I keep this aspect completely parallel to our own system. Basically, every day in Athron consists of twenty-four hours numbered in two sequences from one to twelve. There is a corresponding midnight, and a corresponding noon. So, it’s basically pretty easy to keep track of.
Again, since I am using the system we use in our own world, I probably should have some kind of justification for it. Unfortunately, I don’t, other than happenstance and I admit that that is a weakness in my world-building scenario. Basically, Athron is a world of roughly the same size as Earth, spinning at pretty much the same rate as Earth, and revolving around its sun at only a slightly speedier rate. In a way, the clock-system is dependent upon a natural feature: the rate of spin of the planet. However, just because the day is the same length of time, that doesn’t mean the inhabitants of this alternate world would divide the day into units of time equal to our own. Keeping with the simplicity-in-math model, it would probably make more sense to divide the Athronian day into either two ten unit periods, or even just one ten unit period. Indeed, with the precedent set by the structure of the calendar, we would probably expect the people of Athron to do precisely that. Dealing with intervals of ten units is much easier than dealing with intervals of twelve. The unfortunate reality, though, is that it would cause headaches for the reader. If we use a ten-unit system and it is now one o’clock in Athron, then we can ask: What is the equivalent time on Earth? Answer: one-twelve. It’s not too complicated in terms of math, but one shouldn’t make demands of readers involving ratio mathematics (at least, I don’t think so). Keep it as simple as possible, especially when you are juggling large numbers of things (and twenty four separate hours is a large number). So, as a result of such concerns I’m keeping Athron on a twenty-four hour per day system. Again, this isn’t something mandatory in world-building (if there is such a thing), but it is worth reflecting on and making a well-reasoned choice.
Oh, there is one other possibility you can use. You can “assume” the novel you are writing is a “translation” from a corresponding novel on the alternate world. In such a case, there is no need to concern yourself with distinct hours of the day, or even days of the week or months. This is because you have conveniently translated the alien time labels to our Earthly ones for easier comprehension. But, to that I say, what is the fun in that?