The Sphere, due to its nature, does not, and can not, have a true moon of its own. However a number of Heavenly Bodies pass the sphere close enough that they will be caught by it and will orbit it for a time, anywhere from a day to almost a year, before breaking free and continuing their journeys.
To most people these moons are ill omens, symbols of chaos and catastrophe, as they wreck havoc on the natural order of The Sphere, most of the time the interior is left unharmed by their effects but particularily strong moons can affect even them.
Each of the moons and their effects has been recorded thanks in to no small part to the now lost Luna civilization who revered the moons as their gods and studied them accordingly. According to Lunarian legends each moon is ruled by an entity that is separate but the same as their moon.
The list of known Moons are as follows, the names and other information translated from the Lunarian language.
The Demon Moon
The most feared moon as when it looms over monsterous demons fly from it and ravage the world. What exactly these demons are is frequently debated as on the exterior they appear as living creatures but when cut open they are just a vague, gray, clay-like substance, no muscles, no bones, organs or what not. These monsterous creatures are near imortal and the weakest is as powerful as a strong man and as vicous as a rabid animal, it's not surpising that when the signs of this moon's coming occur that all wars halt and a massive exodus to the interior occurs. Though for the fearsomeness of this horde they have one glaring weakness; they can not exist without the light of their moon. This means that when the Demon moon sets all the demons will become ash and when the demon moon leaves it will be as if the demons never existed leaving just the damage they wrought as evidence of their passing.
The sign of the demon moon's coming is an eclipse of the sun on 7 consecutive days, this is actually the demon moon's last orbit before it is captured in the sphere's orbit, and sure enough exactly a year to the day the demon moon shows up. The demon moon generally lasts for one month every 75 years. According to Lunarian legends the ruler of the Demon moon is an Archfiend whose name translates as Oblivion.
The Devouring Moon
A pitch black moon whose appearance distorts the natural gravity feild of the Sphere. Most of the time nothing comes of this, people on the exterior feel lighter while those in the interior feel heavier, however occasionally powerful gravity storms will flare up causing entire towns to be ripped out of and pulled up towards the moon, or, in the interior, to collapse under anywhere up to 250x the normal gravity.
This moon appears for about a weak every three or so decades and according to the legends is ruled by a king who gorged himself while his people starved and is now cursed to eat until the world ends.
The Moon of Bounty
A crystilline moon that absorbs the sun's light and reflects it as a gentle warm glow. While this moon rules crops will grow at a dramatically increased pace and injuries and sickness will pass at the same rate. To the Lunarians this moon was a blessing from their gods. However it only appears for one night a year and even then in only a small area the location of which can never be predictided. The Lunarian legends state that the ruler of this moon was a peasent woman who prayed to their gods for a way to save her son who was horribly injured in an enemy raid, and her village whose crops where destroyed in that same raid, in response she was given this moon.
The Warring Moon
A blood red moon whose appearance foreshadows a battle that will determine the fate of many, as such it appears irregularily but always anywhere from a week to a whole year before the battle, the length of time between the appearance of the moon and the actual battle is commonly thought to reflect the importance of that battle. The Lunarian legends state that this moon is ruled by their war god who appears before battles that personally require his attention.
The Blue Moon
An unpredictible moon that causes the unpredictible to happen. Like it's namesake it is as deep a blue as blood is red and seems to affect probability to increase the chance of the unlikely happening. Not coincidently this is said to be the moon of the Lunarian's god of luck.
The Shadow Moon
Whether or not this moon exists or not is up for debate. It was certainly believed to exist by the Lunarians and several reports of it's appearnce has been reported in modern day but the majority believe it to be just a superstition. According to legend this moon is an omen of death, if you see it rise then you will die before it's set and only those about to die and those closely connected to them can see the moon at all, in adition it doesn't matter whether it's day or night for this moon. Not surpisingly this moon is ruled by the Lunarian's god of Death.
Moon of the Oceans
The most basic moon and in Lunarian legends home of their chief god. Unlike the other moons whose effects aren't affected by distance for this moon just how far it is the major determinig factor in this moon's power. In theory the effect of this moon is simple, the water level on the exterior increases as the water level in the interior decreases; the distance of the moon makes the difference about whether the effect is even noticed or if the level changes so dramatically that the exterior drowns while the interior suffers a drought.
Right, this is my first contribution, I hope I didn't mess anything up too bad, please feel free to add/change anything you want, the basic theory is that various meteors flying through space get caught by the sphere's gravity and swing around it a couple of times before slingshoting back into their normal path, drasitically effecting the sphere in the meantime...
Extra Lunar Notes, Inserted By Someone Else; Decided to add in some notes about the rest of the Sphere's dual system.
The Little Moons
There is a small but enlarging asteroid field that on occasion passes by the Sphere and is almost always caught up whenever it does happen. These moons are ruled by several Lunarian smaller gods and godesses, but have been known to have been caught up consistently by other planetary bodies, thus having picked up some of their strange essences and occasionally cause a smaller version of its effect. It occasionally passes by in its celestial storm and gets caught on another moon; particularly strange is when the Little Moons appear along with both the Moon of Bounty and the Blue Moon, in this cases, weird events happen. Some of this events have been: A small rain of crystallized numen over one village by a Logilo outpost, a gigantic image of a star blazing out of the Heavenly Storm, a Starborn city state suddenly being surrounded by dancing lights exactly 35 tinlas (5 feet) from the ground for an hour, a giant rainstorm over several deserts, and a tornado flying over but not hitting a Daines city. One of the rarest and strangest event was when a meteor crashed down into the ocean by a seashore, shoving a legendary-sized sea monster to breach the surface before going beneath once more, being the subject of a painting by a Lunarian painter, the work survived time and is called "The Moon Fell Into The Sea", by Dominic Uleren Lunfalle.
The Heated Moon
There is a volcanic, unformed world hovering around somewhere in the Sphere system, said to be ruled by the Lunarian god of Fire and when it appears, triggers volcanic eruptions and small ocean changes by its gravity, and its heat causing firey meteor showers and heat waves. As its orbit places it close to its star but unusually close to synchronization as if it was actively hiding behind its parent star to avoid the Sphere in an egg-shaped orbit, and as such only appears so rarely entire empires rise and fall and the landscape noticably changes in the times between the appearances, even moreso than other moons.
The Sun Of The Sphere, Formally Known As Soluna By The Luminaries
Soluna, the star of the Sphere system, is a moderately sized whitish star that is usually yellowish but occasionally flashes blue or red or other colors depending on how the Sphere's center Prison cloud is eminating by the moment. Soluna is the given name of the star by the Luminaries, a message gradually leaking through subspace into the sleepingish minds of the First and her host of Luminaries, flowing into the subconciousness of the Starborn over time (being formed loosely by the Luminaries energy exertions) and eventually spread to everyone else. The Lunarians didn't declare it a home of one of their pantheon, but it was accorded a place of importance, namely, if oddly, as the storyteller of tales, being a cupbearer (Of all things!) to the Lunarian gods and goddesses, then being promoted to the brightest star in the sky, thus becoming the witness to many epics and tales, being two places at once (Day and Night Soluna) in order to see nighttime events. Soluna has an extremely unusual gravity field, complicated by the complexity of the long-term grabbing of the Sphere unminded by the Vortumbrae and only minorly noted by Luminaries. It happened to grab a large portion of a tiny nebula passing by. The waves of gravitational fluxation of the Sphere drew a huge amount of small planets together, forming n asteriod field of materials amazing on a subatomic level. The field mostly settled down into the Sphere's part-time moons and full-time planets of Soluna, but left a field of similar matter as the Little Moons, which is growing by the influx from the Sphere. Soluna is somewhat similar to a Luminary in the period before assuming full conciousness due to the extremely longtime presence of Luminary radiance, and may eventually assume Luminary status, appearing externally normal but actually being a Luminary settling its Star body where it is for the Sphere, working to pick the padlock that binds the Luminaries with the First inside the Sphere so they can leave at will.