Dark matter is basically added to the situation to explaine the gravitational pull in the absence of visible matter.We know that the gravitational force is space time geometry.So my suggestion is,what if our space-time is not so uniform afterall and containes wrinkles.Now these wrinkles will give rise to gravitational field,but no matter will be present,hence,producing an illusion of matter or dark matter.Also these wrinkles might not have gathered matter due to presense of deeper wrinkles in its vicinity.Under this alternative,we won't require any dark matter to explaine the situation at hand.

Ooh... nice!

 

But what happens when matter passes over/through one of these wrinkles? Would it's density increase?

Are you suggesting the possiblity of gravity not being a constant then?

 

EDIT- sorry didn't read your first post properly

Here's a better attempt to explain away dark matter:

 

http://xxx.lanl.gov/abs/astro-ph/0507619

 

General Relativity Resolves Galactic Rotation Without Exotic Dark Matter

 

A galaxy is modeled as a stationary axially symmetric pressure-free fluid in general relativity. For the weak gravitational fields under consideration, the field equations and the equations of motion ultimately lead to one linear and one nonlinear equation relating the angular velocity to the fluid density. It is shown that the rotation curves for the Milky Way, NGC 3031, NGC 3198 and NGC 7331 are consistent with the mass density distributions of the visible matter concentrated in flattened disks. Thus the need for a massive halo of exotic dark matter is removed. For these galaxies we determine the mass density for the luminous threshold as 10^{-21.75} kg.m$^{-3}.

Ooh... nice!

 

But what happens when matter passes over/through one of these wrinkles? Would it's density increase?

 

Well!As space-time geometry tells matter how to move,so,if a deeper wrinkle exists in the vicinity of a shallow one,matter will never accumulate there.

Here's a better attempt to explain away dark matter:

 

http://xxx.lanl.gov/abs/astro-ph/0507619

 

 

Its not just about galactic rotation,its also about the ultimate fate of our universe.