Gravity is so weak because . . ?

Having been immersed in the last few months in the complexities of quantum mechanics, and other reading including about the quantisation of space itself, it has been too easy to park the subject of gravitation.  But it has emerged in two places recently, the Horizon programme and an article of the IoP.  Apparently the reason the 4th fundamental force, Gravity, is so weak is that the world we (and the other three Forces) inhabit has only three spatial dimensions and act entirely within them, whereas gravity exists mainly in a 4th spatial dimension.  Not a macro dimension (which would contradict GR) but a micro one, too small for us to observe.  A neat analogy is that a tightrope can only be walked on in one dimension, but ants can also walk all around it.

But the line defining the x dimension is just a mathematical construct, it has no thickness or circumference.  Put an ant on a spider thread, it can rotate around it (as a man on a tightrope could), but not walk around it.

Centrifugal force is not a force, unlike the centripital force (which is a true force) required to balance it in a stable, whirling (can on a string) system.  Centrifugal force is known as a virtual or "imaginary" force, a consequence of an object with mass and hence inertia being constantly accelerated in a circular path.  Gravity is the same kind of imaginary force, such that in the case of an orbiting planet, the two imaginary forces, centrifugal and gravity, balance each other.  The object is being acted upon in two ways (a) by the elastic space it and its massive partner are being accelerated by, thereby sharing a dent in the space, and (b) by the inertia of the orbiting masses resisting the dent pulling them together.  Gravity replaces the centripetal force applied by the string.  Hence gravity and centrifugal are equivalent, the mass and its inertia affecting them both identically, but the difference is a two-dimensional shape, the circle (more generally the ellipse).  Gravity has an extra dimension S4, and it is one that we all experience.

Maybe that extra dimension is just time T, but I would rather use S4 and then determine if S4 = T.  But no need for gravity to be locked into "micro-S4" - it is not a force at all (let alone a fundamental force).

Everyone is hung up about dark matter being needed to explain why galaxies clump together as they do, and dark energy to explain why dark matter is not causing the expansion of the universe to slow down, but accelerate.  The higgson explains why matter has mass, but I wonder if it can explain how nothing can also have mass?  It is clear that dark matter can be mapped by the observation of distant objects through gravitational lensing.  But can't the lumpy shape of dark matter be modelled instead by clumpiness of space itself?  Not easy, I know.  I need dark energy, not to expand the Universe, but as the rotational potential energy in S4 with which space is whirling all the mass within it.  If I had my way, the zero of potential energy would be the bottom of the largest possible black hole, and the value at "infinity" would equal the total DE.  Though that might not be very convenient.

I am worried by the finding that the Universe is flat, and therefore infinite, as infinity is just another mathematical construct, 1/0, impossible in reality.  Seems to me they are asking the wrong question, and just ending up with the number they first thought of.  Naive, maybe, but interesting . .