#mellanus

[whirligig-girl]

The satellite planets of the gas giant Omen, as well as its largest coorbital: Gymnome, Eaurp Guz's homeworld and the setting of Train Puzzle dot exe.

Oldsky, Lake, and Rival are all also known to have life, with Oldsky having a biosphere that is as fully developed as Gymnome.

The orbits of the moons of Omen. The periods are +25.3 hours, +50.7 hours, -174 hours, +236 hours, and +628 hours. Notably, the largest moon, Oldsky, is an obviously captured satellite in a retrograde orbit, but it is thought that Rival and Wanderer are captured satellites as well, with the only surviving original moons of Omen being the three dead-comet-like inner regular moons, which have 7-10 hour periods, as well as Spark and Lake, though the latter have likely been altered at some point in their history by collisions with protoplanets from the inner Zwo-nmu Star System.

The horseshoe orbit of Gymnome wrt Omen.

Scale comparison.

[whirligig-girl]

Ok let's start with just the astronomical facts for now.

I'm still working on getting my mellanoid slime worm calendar up and running, but for now, here's the observational facts.

Mellanus is a roughly 0.8 earth-mass planet which is co-orbital with a 341-earth-mass gas giant called Omen--so named for how its apparitions correspond with changing climate. Mellanus' average orbital period is exactly equal to Omen's, however, it never completes a year of that length. Mellanus spends about half of the time in a lower, "hot" orbit, and half of the time in a higher "cold" orbit. When it catches up to Omen roughly every 15 earth years, it exchanges energy with it and climbs into a higher or lower orbit. Omen's orbit essentially does not change at all as this happens, while Mellanus' changes substantially. The cycle lasts about 31 earth years. To be more precise:

Mellanus hot orbital period: 271.316538 earthdays = 23441749 seconds Omen period/average Mellanus period: 286.293878 earthdays = 24735791 seconds Mellanus cold orbital period: 301.851079 earthdays = 26079933 seconds

Time between Omen encounters: hot cycle: 5186.2523 days = 14 earthyears 2 lunamonths 15 earthdays = 448092200 seconds cold cycle: 5554.86274 days = 15 earthyears 2 lunamonths 19 earthdays = 479940141 seconds

The sum of these two cycles is 29 earthyears 5 lunamonths 4 earthdays or = 928032341 seconds, and is called an Ominous Cycle or an Omicycle. It is the time it takes between two Omen apparitions, completing one circuit around its co-rotating horseshoe path.

Mellanus' sidereal rotation period: 17 hours, 32 minutes, and 3.23 seconds = 63123.23 seconds

The rotation period of Mellanus is not sufficient to produce a usable day length, as it would differ from the solar day by a few minutes, just as on Earth. However, Mellanus does not have a consistent solar day any more than it has a consistent year--the days are longer during the lower, faster, hotter orbits. (day is slower when the orbit is faster? yes--a result of reciprocals in the formula for calculating this)

Inner solar day: 63293.7s Average solar day: 63284.7s Outer solar day: 63276.4s

So the hot days are 17 hours 34 minutes 53.7 seconds and cold days are 17 hours 34 minutes 36.4 seconds The difference is 17.3 seconds. This can not be ignored, as it would correspond to the day length lagging behind by a full day over the course of an Omicycle.

There are: 370.364649 hot-days per hot-year 390.865264 days per year on average 412.158925 cold-days per cold-year. And there are: 19.1151351 hot-years per hot-cycle 18.40266 cold-years per cold-cycle 37.5177951 average years per Omicycle. A successful calendar for Mellanus must have the following characteristics: * It must track the solar day without drifting over the course of the year, and while accounting for the two different values for the solar day. * It must track the changing seasons of Mellanus, as it has an earthlike axial tilt, and without drifting over the course of many years, and while accounting for the two different values for the orbital period. * It must track the path of Mellanus about its horseshoe orbit, without predicted Omen apparitions falling too short or too early over time. And it must do so successfully for at least the roughly 800 or so earthyears that the calendar has been in use.

Can you see, perhaps, why I'm going a little bit mad?

So far what I have is a way of tracking the number of days per year using months (and two intercalary months during the cold orbits), and a way of tracking years per omicycle with intercalary years added to account for the extra 0.5177951 years per omicycle. And a whole lot of other nuance that isn't as important, like how the different day lengths are reckoned. I want to have Omicycles be the top level that iterates over time, with years considered cyclical (i.e., the year will roll over from 37 or 38 to 1, just as months roll over from 12 to 1 on Earth), and so the problem is to have a system of leap years that can fit within the 37-38 year omicycle... and also how to set up the intercalary years so that they do not completely wreck the alignment of the seasons, since the intercalary years are almost always an added coldyear but are sometimes an added hotyear. Suffice to say... it's a bit of a mess. I will figure it out though. And it will be so cool. And it will have virtually nothing to do with star trek or with slimegirls but it will be a functional calendar for a planet in a horseshoe orbit, which to my knowledge does not exist.

[whirligig-girl]

In the slamp (slime swamp) of Mellanus. (originally drawn March 14th 2023)

Slime webs hang between the canopies of trees ready to catch insects and small flying invertebrates; a layer of photosynthetic slime catches all the energy that it can that falls through the trees and makes do with carnivory when the light is too dim; huge calcium stones, the shells of huge invertebrate-slime-hybrids that lived twenty million years ago, dot the landscape and provide an anchor and a highland in what is otherwise a flat landscape. And everything is so, so, so damp.

Eaurp Guz, breathing in deeply: "Ah. I love nature. It's good to be home."

[whirligig-girl]

You know, for a kerbal space program planet modder, i've really been dragging my heels when it comes to major aspects of mellanoid slime worm worldbuilding--such as the planet Mellanus itself.

To be fair, that's pretty normal for a star trek world. We don't have any really good consistent canon maps of, like, Qo'noS or Vulcan, despite both appearing from space many times and all we know about their culture.

Anyway here's a very rough draft of a map of mellanus. I wanted lots of east west trade routes and north/south migration paths. TBH I might add more smaller continents/larger islands, for two reasons:

more land implies more shallow oceans, boosting the biomass available for mellanoid aquatics

some of these continents would have deserts that make them uninhabitable to mellanoids, and I want a little more room to play with.

Part of the problem is that Mellanus cools and warms in a 35 year cycle driven by close encounters with its coorbital giant planet Omen. And I don't have a solid idea of how that should affect the climate bands. Not to mention that you should expect sea level changes over the course of the cycle as well.