And (correct me if I'm wrong) gravity IS described as space-time distortion in general relativity.

Apples are Fruit, Not All Fruit are Apples. Hence Gravity is a type of space-time distortion, or rather it manifests as such, we don't know exactly what gravity is, but just the rules that surround our interaction with it; however, not all space-time distortions are gravitational. Electromagnetism can also create space-time distortions and then there are things like vacuum fluctuations which in which the base fabric of space is in flux by itself.

[quote name='Oberon_Command' timestamp='1348514873' post='4983325']
Spherical geometry is a easy example of a geometry that doesn't have the Parallel Postulate as an axiom - consider that in Euclidian geometry, the angles in a triangle add up to 180 degrees; but in spherical geometry, one can have a triangle that has three right angles!

Considering that the Parallel Postulate even states that it only applies to two dimensional geometry, the fact that it doesn't hold in three dimensional geometry is hardly surprising.
[/quote]

Spherical geometry is not three dimensional. It's a geometry that treats the surface of a sphere as a two-dimensional surface.

http://en.wikipedia....erical_geometry

Indeed - although thinking of a sphere is a way to visualise it, a two-dimensional surface doesn't have to have a higher dimension to "curve in" (the same is true of the idea that the 3D space of our Universe may have curvature, which would mean axioms to do with triangles and parallel lines don't hold - this doesn't mean there's a higher spatial dimension that the Universe exists in).

how exactly does a limit get derived from causality?, i'm assuming this is going off the understanding that going faster than light can theoretically mean going back in time(which i never really understood why this is so, all i ever find on the subject is that's it's apparently possible, but nothing ever explains why it's possible).

Simultaneity:
http://www.pitt.edu/~jdnorton/Goodies/rel_of_sim/index.html

Simultaneity ("now") slices that tilt based on frame of reference:
http://www.pitt.edu/..._sim/index.html

Simultaneity slices with more tilt than a signal leads to a signal that travels toward previous "nows":
http://www.pitt.edu/...hyon/index.html

After you read these, it should be clear (as mud) that, in reality as we know it, signals and observers can never travel faster than the speed of light, and that light-speed signals can never travel toward previous "nows" (the past) in any frame of reference.