The Cosmos of Elves & Espers is a distinctly fantastic one, with planetary systems consisting of nested crystal spheres floating like bubbles in the vast ocean of ether. The Cosmos consists of planes layered in successively higher “vibrational frequencies”: the void, space, the aether, and the astral.
The Abyss. a.k.a. Sub-space or Null-space. At the lowest level, devoid of vibration, devoid of anything save Azathoth, there is the formless Void. Matter, even if it could be projected into sub-space, cannot last long, though some foolhardy civilizations have experimented with ways of sending messages through sub-space.
The realm of dull matter, possessing neither life nor soul (in Elves & Espers you can have purely material constructs that imitate life, but without the vital spark of prana energy they are soulless automatons). Space is big and empty. There is no air or gravity there. Travel is limited to slower-than-light travel via conventional means such as rockets; there is no FTL method of travel or communication possible within space: you must use the higher vibrational planes.
Structures and ships need not be aerodynamic, but they must be proof against vacuum and radiation. Artificial gravity is possible, but requires magic or super-science; at this level the crystal spheres that surround the worlds and carry them in their orbits through the ether are invisible and intangible (like everything that exists in the Ethereal Plane). Similarly, force fields and beam weapons can be constructed, but only by using magic/technology that draws on the higher planes. Without knowledge of the higher planes, tech is limited to purely physical things like missiles and armor.
Space travel, except for short jaunts to cross a crystal boundary, is usually reserved for those who cannot travel in the higher planes, or for situations where such travel is impractical such as moving a truly massive object. Space travel remains relatively primitive, with top speeds rarely more than about 14% of light speed; civilizations usually abandon improving their space travel technology as soon as they master (or encounter) ethereal travel.
Using the geocentric solar system as an example:
A.k.a. Hyperspace, Kirby Space The medium through which light and gravity propagate. Crystallized aether spheres surround planets and are in turn embedded within larger crystal spheres that define the orbits of the planets. The spheres rotate at non-uniform rates, giving the illusion to those measuring from a planetary surface that the orbiting planets are tracing out ellipses. At the outer edge of a planetary system is the largest sphere that defines that system: the firmament. The spheres of the planetary systems are swept along together in the currents of the aether that form the galaxies.
The aether is not uniform: it has eddies, currents, and even storms. It’s also not completely homogeneous, but is composed of the elemental quintessences. It is composed of all the elemental quintessences: anapnon (air), phlogiston (fire), geon (earth), and neron (water). Anapnon is the dominant element. The elemental quintessences are the embodiment of the metaphysical properties of the element, rather than instances of them; that is, phlogiston isn’t fire, it’s that property which allows material to burn; anapnon is the property that allows living creatures to breath air, and so on. Thus because of the presence of anapnon, living beings of all kinds can breath in the aether, even if in space they would require radically different atmospheres (such as ammonia instead of oxygen). Likewise, because of the geon that permeates all solid objects, any solid objects that have been rendered ethereal have their own gravity and any smaller body can treat a nearby larger body as if it possessed 1 G of gravity (for conscious beings, this is voluntary, and they can choose which nearby larger object to orient towards or even ignore the tug of gravity, for inanimate objects the nearest and largest dominate, in that order).
Most planetary systems are geocentric: there is a particular planet that is the center of the collection of spheres that make up the system. Some are heliocentric (the center-most object happens to be the sun); in rarer cases there is no central object, or the central object is not an ordinary celestial object like a planet or sun but something unusual like a gigantic egg or a machine. The laws of reality within a planetary system can differ from one to another, though they generally are similar enough that visitors to the system can survive and not just become a smear of not-atoms drifting through not-space, though their technology or magic may not work, or work differently. In essence the GM should make it so that adventuring in “foreign” systems is perfectly feasible but may contain interesting surprises.
There are life forms and even entire civilizations are native to the ethereal plane. Some are adapted to live in close proximity to gross matter (essentially denizens of a planet that happen to spend all or most of their time ethereal), others live far from planets, or even outside the firmament altogether, in the space between the stars.
The crystal spheres are solid to ethereal objects, but there are always openings. All spheres are open at their poles. In addition orbital spheres (the spheres that planetary spheres are embedded in) have openings around those planetary spheres allowing them to rotate freely: the openings are tiny compared to planets, but quite sufficient even for fleets of ships.
Spheres surrounding planets themselves are open at the poles, but there is an “axle” connecting the poles that transfixes the planet and causes it to rotate. These axles are multiple (usually 3) helices of crystal aether that connect the opposite poles. Ships can enter and exit a sphere through the poles by flying down the axles if by no other means; this can be dangerous because of the swirling vortexes of aether wind that naturally occur there. It is common for advanced aether-travelling civilizations to have space ports at the poles, or even ethereal spaceports built on the axles themselves.
Ships that are properly equipped can also get past the spheres by dropping into regular Space, or if they have the capability ascend to the Astral plane and transverse the sphere that way. Note that physically ascending to the Astral in close proximity to a large amount of gross matter (such as from within a planetary sphere, particularly if the planet has an atmosphere) is extremely dangerous to any but a trained adept; it is not for nothing that most travelers from planets send merely their astral form (soul) and do not attempt to transcend bodily.
If the sphere is surrounding a planet the planet is affixed to the helices and rotates with the sphere. In Space, the boundaries of the sphere coincide with the boundaries of the atmosphere if any. The spheres are extremely tough, but not unbreakable: any cataclysm that destroys the planet will probably destroy its sphere and the shards of the sphere will drift through the aether.
Matter can be projected into the aether by means of magic or super-science; high speed travel is made possible by making entire ships ethereal. Typically such devices resemble multi-dimensional tuning forks and their vibrations adjust the vibrations of objects within their influence to match the higher or lower frequencies of the different planes. Since the aether has “wind resistance”, ships that are build to travel the aether are generally streamlined and aerodynamic: lift isn’t necessary except near planets but control surfaces allow for better steering.
In Ethereal travel what matters is not the spacial distance but the number of spheres that must be traversed and the relative positions of the planets. Each successive sphere encloses a volume of ether at a different vibrational frequency (higher/faster as you go farther out). Simply travelling from an arbitrary position on one sphere to the corresponding position on the next sphere out takes 3 days. To go from planet to planet, though, requires catching up or moving back to its position within its orbit. Ships travelling in the aether are either moving with the current (Spinwards), in which case it takes and average of 5 days to move from one planet to the next, or against the current (Anti-Spinwards) in which case it takes 10 days. If the GM hasn’t determined it, roll 1d24 and assume that results are days travel spinward. For positions greater than 16, it’s actually faster to travel anti-spinward. Calculate the amount of travel to reach the anti-spinward positions by subtracting from 24 and multiplying by 2. Reaching the pole of the planet’s orbital sphere from the planet or vice-versa takes approximately 6 days, while pole-to-next-pole outward or inward is always 3 days. Circumnavigating the sphere in the spin-ward direction takes about 24 days.
Once you’re beyond the outermost sphere of the system (the firmament) travel takes a steady 1 week per light year. At this point most ships translate to a higher plane to use Astral travel.
Actually crossing from inside to outside of the crystal sphere takes about an hour at one of the openings or a whole day via translation into Space and back (since you have to cross the entire thickness of the sphere while remaining in Space). Local conditions and ability of the crew may affect the travel time (See Crawl #11 “Life Aboard”).
The Astral Plane
A.k.a. Ditko Space. The realm of prana, light, energy, and mind. Finite minds find it hard to perceive the astral realm clearly; its features are translated into simpler forms that are easier to comprehend. Prolonged exposure can cause weaker minds to go mad, and ships are usually designed to shield passengers and crew from directly gazing upon the ever-shifting forms outside.
There are two modes of astral travel: psychic travel and physical travel. Psychic travel works as in the Basic Psionics Handbook. Physical travel involves translating characters’ physical bodies into the Astral Plane (which almost always involves using a ship to shield them and particularly their minds from the rigors of astral travel).
Travelling physically into the Astral Plane generally requires a ship equipped with an Astral Engine; navigating through the Astral Plane to arrive close to your destination, and how much subjective and objective time that takes requires casting the Navigate Astral spell. Physical exposure to the astral Plane results in Astral Fatigue. It is difficult to physically enter the Astral Plane from within the sphere of the firmament: -1 d per sphere inward on the Astral Navigation check.
For non-psychics, every week as a passenger, day as a crew-member, or watch you take as a Navigator (including being a secondary navigator learning a route) requires you roll a Will save vs. DC 10 or gain 1 level of Astral Fatigue. Astral Fatigue has the following effects based on level, cumulative:
- Time Ghosts. You see occasional visions of older and younger yous moving about the ship; they are unable to see or interact with you.
- Figures constantly at the edge of perception. -1d on init.
- Uneasy sleep. No longer regain Spellburn or Stamina with a night’s sleep.
- Insomnia. No longer regain spells, Luck, or heal naturally.
- Temporal fugue. When you try an action that requires a roll, roll a d3 in addition, on a 3 you bifurcate and there are two of you acting independently for 1d3 rounds (this may be an advantage, or it may not. E.g. if there is only room for one more in the lifeboat…). At the end of the period, flip a coin to see which one remains.
- Voices in your head. Gain a random minor madness.
Astral Fatigue levels can only be reduced by leaving the Astral Plane; for each day in a lower plane a DC 10 Luck check reduces the level of Astral Fatigue by one. Natives to the Astral Plane never suffer Astral Fatigue.
Astral Travel is dangerous, so ships often travel in convoys. To make sure they all follow the same route one Navigator must be chosen as the lead Navigator before the spell is cast: it is the lead Navigator’s spell check that determines the parameters of the route. The other Navigators must cast Navigate Astral, but as long as they roll a success (12+) they will follow the lead Navigator’s ship with the same result as the lead. Ships must be in sight of each other in order to follow the leader in this fashion, and all the Navigators must know the destination intended, though they need not know the route. Hostile ships may likewise follow the leader into the Astral, but only as long as they too know the chosen destination. If they get it wrong, treat it as if they rolled a 1 on their spell check.
Still To Come
This has gotten really long, so I’ll add Astral Encounters and Interrupted Journeys for another time.