The fifth dimension can mean one of two things, depending on whether or not you count Time as a dimension and number it.
If you do count time, then the fifth dimension is actually referring to the to the fourth Spatial Dimension. In that case, you'll find full details on the Fourth Dimension page. In Astrophysics it's quite common to consider time a dimension.
If you don't count time, then the fifth dimension would be the dimension beyond the fourth spatial dimension. It's the second spatial dimension beyond the three spatial dimensions that humans can observe, and the fifth overall spatial dimension. In purely mathematical fields such as Geometry, time is irrelevant (or handled via non-dimensional abstractions), and thus not counted as a dimension.
The relationship between the fourth and fifth spatial dimensions is analogous to the relationship between the third and fourth spatial dimensions. You'll find that relationship explored pretty thoroughly on our Fourth Dimension and Fourth Dimensional Lifeform pages. A fifth-dimensional lifeform would have the same advantages over a fourth dimensional lifeform that the 4-D lifeform had over mundane 3-D people. In addition, the 5-D lifeform will have those same advantages over us, as well.
Unique to the Fifth Dimension
In addition to the implications of it's similarities to the fourth dimension, the fifth dimension may have some additional properties:
- According to Gerard 't Hooft's Holographic Principle, the fifth dimension is the fabric of Spacetime. Just as a hologram lets us see a 3-D image on a flat surface (and note it's curvature and volume), says Hooft, the curvature of time and space models the fifth dimension.
- According to Rob Bryanton, the fifth dimension is the Probability Space of our universe. This hinges upon the notion that there are two directions one can travel in regards to the Temporal Dimension, either forwards or backwards in time. Time Travel is controversial, but if Bryanton is right, the Fifth Dimension contains all the Parallel Universes of Branching Time and the Multiverse.
Game and Story Use
- Adventure Seed: Tentacles of Space
- Be sure to check out the Fourth Dimension and Fourth Dimensional Lifeform pages for more ideas. They'll cover the majority of the things you'd want to do with the fifth dimension.
- See also Another Dimension for the (far from accurate) way this gets handled in fiction and media.
- A physicist and a mathematician may mean different things when they say "fifth dimension" - this isn't a huge deal, but it might justify a minor penalty on the first die roll or two of collaboration if the character's don't know each other's backgrounds.
- Following the Bryanton model:
- Moving relative to the fifth dimension might be how a Planeswalker, Time Master, or Amberite fine tunes the world to their liking and/or travels the Planes of Existence.
- A fun Negative Space Wedgie might be a fifth-dimensional rift that randomly connects to different times and places, and spews forth people and things from alternate realities.
- Be careful. If anyone in your group is old enough to remember the early '70s, any mention of the Fifth Dimension will provoke an impromptu rendition of "Age of Aquarius". (At least that was this troper's reaction, he said dating himself).