Gravity in most of the many regions of arcane space is an "all or nothing" affair. The level of the "Earth World Standard," or EWS, is given an arbitrary value of 1.0 for ease of comparison to non-standard values.
Gravity is a property of almost all matter, whether solid, liquid, gas, energy, or magic (which is simply another form of energy). Thus it is possible for a fire body or an air body to be the orbital center of a particular sphere, or a conduit to the positive material plane to act in a similar fashion. With the many variations in air quality, temperature, size, and magical properties of various kinds of matter, one wonders why gravity tends to have this arbitrary distinction between EWS and 0. The truth is that other values for gravity do exist, but they are rare and tend to arise under unusual conditions or magical influence.
To simplify matters that otherwise would otherwise become needlessly complex, assume that worlds with gravities in the range of .8 to 1.2 are considered "normal," and that no bonuses or penalties are received when entering an area of lower or higher gravity in this range.
Planets with gravities lower than .8 have the following effects on people experiencing this gravity (assuming the person is from an EWS world where gravity is 1.0):
Increased Strength (objects of the same mass weigh less, enabling muscles used to higher gravities to accelerate them quickly and more easily)
Reduced Dexterity (the muscles used to move the body for normal tasks are used to greater resistance, and therefore tend to overcompensate for motions)
Thinner Air (lower gravity can hold a smaller amount of air against a planet; NWP's such as Endurance or Running can offset this)
Increased Height (less weight means elastic supportive tissue can expand, resulting in a height increase; astronauts in 0 gravity have reported height increases of 1 inch or more)
Long-term exposure to lower gravities (a month or more) negates the above advantages and disadvantages (except for increased height), and has the following effects:
Weakened Joints (bone material becomes concentrated at areas of high pressure due to weight of the body; decreasing this pressure reduces the need for dense bone at those points, resulting for weakened joints)
Reduced Heart Strength (lower gravity means the heart has to work less to move blood upward, and like any muscle if it is exercised less it will lose some of its strength)
Note that these long-term effects are not particularly noticeable while the person is still in the area of low gravity; once the person returns to an EWS-gravity planet these effects will become obvious (pain in the joints, easily fatigued, heart palpitations). After time the person's body will recover, but care must be taken to avoid injury during these times.
Also note that in some cases the long-term effects may be helpful - a person with a history of joint problems or a weak heart would gain some relief by living on a low-gravity world, and would not deteriorate much beyond their current level.
Modifiers to Abilities When Under Low-Gravity Conditions:
Gravity: Strength: Dexterity:
0 - .09 [treat anything in this range as 0 gravity;
note that planets with gravity this low will
probably have no atmosphere]
.1 - .29 +3 (or 30%) -3
.3 - .49 +2 (or 20%) -2
.5 - .79 +1 (or 10%) -1
Other abilities based on Strength or Dexterity (such as Jumping or weapon ranges) will be affected by this change. Alter the allowed actions by the difference between the EWS range (.8 - 1.2) and the current one (for example, a person in gravity .5 would have a multiplier of .3 (.8 - .5 = .3) added onto his Jumping distance, increasing a range of 10 feet to 13 feet).
A humanoid body is better at handling lesser gravities than greater ones. Planets with gravities higher than 1.2 have the following effects on people experiencing this gravity (assuming the person is from an EWS world where gravity is 1.0):
Decreased Strength (objects of the same mass weigh more, requiring more effort to move them)
Reduced Dexterity (the muscles used to move the body for normal tasks are used to less resistance, and therefore tend to undercompensate for motions)
Decreased Height (more weight means elastic supportive tissue is compressed more, resulting in a height decrease)
Long-term exposure to higher gravities (a month or more) reduces (but does not negate) the above advantages and disadvantages (except for decreased height), and has the following effects:
Stronger Joints (the increased pressure causes the bone tissue to strengthen, making them less likely to break; unfortunately, the stress on the joints is uncomfortable and can reduce small-task manual dexterity, such as casting spells)
Stronger Heart Muscle (the heart works harder to pump blood upwards, and therefore strengthens; people with weak hearts or heart problems can easily suffer damage in a high-gravity environment)
Blood Vessel Enlargement in the Lower Extremities (fluids tend to pool near the lower portion of the body; causes no damage, but causes the appearance of said tissue to show varicose veins, which is not particularly attractive)
The first two of these long-term effects will revert after time spent in normal gravity, but the vessel disfigurement will remain. Creatures native to high gravity worlds will be used to the higher level of gravity and will be stronger than normal creatures in EWS gravity (a possible explanation for the Giff...?). Such creatures will also experience low-gravity penalties at earlier levels (i.e., a creatures whose natural gravity is 1.3 will feel at gravity .9 what those from an EWS world will feel at .8). The same is true for creatures from low-gravity worlds visiting higher gravity worlds.
Modifiers to Abilities When Under High-Gravity Conditions: Gravity: Strength: Dexterity: Special 1.21 - 1.4 -1 (or -10%) -1 -- 1.41 - 1.5 -2 (or 30%) -2 -- 1.51 - 1.6 -3 (or 50%) -3 -1 CON 1.61 - 1.7 -4 (or 100%) -4 -2 CON 1.71 - 1.8 -5 -5 -3 CON 1.81 - 2.0 -6 -6 -4 CON, dizziness 2.1 - 2.5 -8 -7 -5 CON, as above + fatigue 2.5 - 3.0 -10 -9 -6 CON, as above + pain
A gravity of 3.0 is about the most a person from an EWS world can stand for long periods of time. Levels beyond that tend to cause damage to internal organs, breakage of items, and similar undesirable effects (it is theorized that one of the levels of the Abyss is a high-gravity plane). Objects with gravities higher than a certain level [?] will not allow light to leave the surface, and there are levels beyond that prevent magical energy from leaving as well.
As before, other abilities based on Strength or Dexterity will be affected by higher gravity. Divide the person's normal gravity by the current gravity to get the multiplier for distance, etc. (a bow that can shoot 210 yards in EWS can fire 91 yards on a 2.3 gravity world (1.0/2.3 = .44; .44 x 210 = 91).
The previous section detailed the effects of different gravities without explaining the causes of it. If gravity is imagined to be an invisible substance that resides within normal matter with a particular attractive orientation (like an infinite number of tiny magnets that attach to the building blocks of matter), then it is simple to assume that low gravity is caused by matter that has less of an affinity for the gravitational substance, and high gravity is caused by materials with a higher affinity for it.
If all types of matter and energy were listed and the gravitational affinity of each was plotted on a graph, we would end up with a bell-shaped curve. The bell would be extremely high and narrow (at the EWS level of gravity), with a broad flat area on either side (tapering off to no affinity and infinite affinity). Most physical matter (solid, liquid, gas, fire) has an affinity of around 1.0 (1.0 is used to indicate the affinity of a substance that, if gathered in a large mass, would result in a planet with a gravity of 1.0). Some sorts of matter (such as crystal spheres, Zodar armor, phlogiston, and Starbeast flesh) have an affinity of 0, resulting in no gravity from that material (perhaps that aids a Zodar's strength...?).
Certain magical creatures that have the (apparently magical) ability to levitate actually utilize some of that rare matter that has an affinity of less than 1. Some extradimensional creatures come from planes where this material is more abundant (such as the Plane of Air, the Astral Plane, and the Ethereal Plane [?]). Planets with low gravities are either partly composed of such matter (possibly from a planetoid colliding with a gate to such a plane in Wildspace) or actually have (several large or many small) portals to such planes which allow the low-affinity matter to accumulate below the surface.
High-gravity materials are more common (and are usually native to the Prime Material Plane), but are not common in large quantities. Quite often these materials are valued for their other properties. Some high-gravity materials (and their affinities) are gold (1.4), mithral (1.7), and adamantine (2.1). Large concentrations of these substances produce planets with gravities higher than 1.0 (in a ratio of "normal" matter to high-affinity matter). For example, a planet made of 50% granite (affinity 1.0) and 50% gold will have a gravity of 1.2.
Planets with gravity beyond the level of 2.1 are almost always due to magic (there do exist tiny amounts of matter with affinities of 10,000 or higher, but rarely is more than an ounce found in a particular sphere, and it is usually scattered among (and part of) several planets). Powerful spells exist that remove the gravitational substance from one piece of matter and transfer it to another. This is unstable, and the "stolen" gravitational substance tends to "leak" away from the material it is concentrated in to nearby material. Other spells use a form of magical lens that focuses the gravity of available matter and enhances it. This also tends to be temporary as the energy input needed to maintain this is quite high (but as a short-term weapon or defense it can be quite effective).
The most dangerous of gravity change is caused by a supremely powerful spell that actually transforms other substances in matter (the anima/life force of a substance, or the mana/magic of a substance, for example) into the gravitational substance. Matter in the area of this magic is quickly changed to pure gravitational substance, which pulls more matter in around it to be transformed, which increases the pull, etc.. Fortunately this effect often destroys the wizard who caused it (and his copy of the spell) because it is difficult to predict the rate of advance of the transformation. When left unchecked, the gravitational area produces a large sphere which continues to increase in volume at a rate dependant on the available matter. When this sphere reaches planetary size, it is often called a "Black Hole." While it does continue to increase in size, the change is small because most nearby matter has been pulled in, and once it is big enough, a significant amount of material needs to be added to increase the size (the size increases proportionally with the cube root of the volume).
Objects approaching a Black Hole become trapped by its gravity (the range is dependant upon the strength of the object's motive force [such as a helm] and the size of the object). As it is pulled closer, the object begins to become affected by the tremendous increase in gravity. All life forms aboard die, and the object collapses into a comet-like streak. Eventually it is pulled into the Black Hole, where its matter is converted into more gravity-substance.
