(Hubris, i know not thy name.)

This is grand slam theory that attempts to tie up both gravity and the 'dark matter' effect.

The basic premise is that tachyons deliver time-dilation/mass & thereby gravity to space-time.

Tachyons are speculative particles that travel faster than light and with inverse time.

Standard matter mass would be a (some?) 3D cross section of the 4D radiant [distribution] of tachyons from standard matter.

Raises the question, what is the dimensional 'footprint'/extent of standard matter?

This is such a constant flow proximate to matter it accounts for the smooth curvature into lower dimensionality that is gravity.

I will say that our space-time experience happens on the luminal sub-luminal 'side' of space-time or within a bounded luminal sub-luminal region that is space-time.

Note: any next lower (N-1) infinite spatial dimension can bifurcate an N dimensional infinite space.

I'll leave in or on space-time a smidge fuzzy for now.

There might be a limited 4D extent/width/band/thickness of space-time (might be the degrees of freedom that allow time to pass/happen). And perhaps tachyon radiation is on both sides of space-time and both sides of the space-time 'band' have some membrane containment that most tachyons encounter.

So tachyons arrive at the other (superluminal) side of space-time so byenlarge they only deliver time-dilation/mass to space-time that we observe.

I believe with black holes the extreme compression creates time inversion and radiation of higher speed tachyons, so many of them that do eventually encounter space-time do so at a great distance from the source black hole. This would be the 'dark matter' effect.

The constant fine mist 'halo' of tachyon mass delivered to space-time at far distance from their black hole source.

This mass most likely spreads out from the tachyon delivery point(s) and is refreshed on an ongoing basis.

There may be something that slows (some?) tachyons down [in their domain] and those drift towards space-time. That would account for the great span/reach of the 'dark matter' effect.

Aside: It might be all tachyons eventually drift towards space-time (DE?), but that is beyond this/these proposition(s).

Perhaps small, nearby black holes could be observed to see if some invisible mass at some distance beyond expected gravity was apparent.

Something orbiting more rapidly and further out than gravity alone could account for.

If the total 4D tachyon output were combined it would be a great quantity, but since space-time, proximate to matter, only includes a very limited 3D cross section this may account for why gravity is such a weak force.

It might be that all or some of the other major forces are largely contained within space-time.

It might give a way to make guesses about the total 4D output of tachyons.

Does seem likely that tachyons would be all around us,

but there could be some aversion property of space-time.