We know that space is expanding, and hence also that space have some kind of density (or a stretching property).  This already known stretching property of space is enough to understand the nature of gravity. It’s not necessary to “invent” more unnecessary properties or expressions.  

Consider that matter consumes / contract space. This would cause space gradually to “thinning out” (or stretch) towards matter.  And this is exactly what the old expression: “The curvature of space” - really mean.

Such simple, basic, deeper and coherent understanding of the nature of space has several consequences.  One of these is;  that space vacuum between two bodies becomes stronger affected, simply because 2 bodies both affects the same area between. Hence a stronger space vacuum (between the bodies) is a result, - The space consuming “competition” between two or several bodies is the cause of mass attraction

The cause of ADG is the relative change in "density" of space per unit distance. Or (in other words) the relative level space is stretching per meter. 

Another consequence (of the same simple thought) is that matter will consume / contract space from both an inwards and an outwards direction. 

But because space towards an inwards direction (of a body) is gradually limited / “trapped” / encircled by matter, the inner space must be affected gradually stronger. 

This combined with a deeper understanding of the cause of ADG (acceleration due to gravity)  leads to the conclusion that  ADG in a homogeneous mass must be stable (not decreasing) towards a central direction of a body. This should be easy to confirm by measuring experiments of ADG towards the centre of (for example) a 200 ton homogeneous well define mass.  (Central measurements with a borehole gravimeter ).

The necessary math is already available; all what is left is to understand the deeper meaning of it.

For example it is known that when radius away from a body doubles, ADG is decreasing 75%.

This is proportional to that also the square increase is 75 %,  - which logical shows that ADG depend of the “access to space”, - and hence this a mathematical language that already shows that space is consumed / affected proportional with the “access” to open space..

Inside a (homogenous) body (and the whole way to the centre) ADG will always be the same as at the surface. This reflects that the inner total gravitational potential always is the same.  (For example if the Earth was double so big ADG would be 2.5 m/s^2 the whole way to the centre).

Another consequence is that that dark matter probably only is an area in space “trapped” (encircled) by space-consuming matter and hence naturally a stronger affected / deformed area. 

The same “track” also seams to be able to bring light to the mystery of the cause of black holes, and also solving the mystery why the size (strength) of these are proportional with the size / mass of a galaxy.

The spin of the elementary particles consume / contract spaces.  A consequence must be; a culmination point at which space absorbs the entire energy of the particle. The absorbed energy (contracted space) must be released, this force a particle to (unwind).  As the result, the particle release 'twisting' space around it until a new culmination point is reached at the opposite end. This shows that a particle constantly oscillates between two states: a 'hard compressed space' (when it is perceived as a "hard particle" matter) and opposite, - a wave.

If one particle of a nucleus releases space, another particle immediately uses such released space for the opposite action (to contract space) because such cooperation saves energy.

Naturally the strong force seems to be an inevitable result of what once probably only was chaotic spinning particle, and hence the strong force is: collective coherent osculation frequencies due to opposite spin of space whirls. However the force of gravity is caused by the total amount of contracted space that the strong interaction always keeps together, which mean that the strong force and gravity must be united.  

The expected result of central gravity measurement can force us to such considerations, since we can very easy be ‘forced’ to understand how matter contracts space.

Based on the Hubble Constant we should expect that also distances (here) inside a gravitational field expands. But because this is not what are observed the conclusion (so fare) is that the force of mass attraction “is stronger” as the expanding Universe.  This conclusion seems to be doomed to overturn. 

When the above mentioned expected central gravity measurement confirms that ADG not is decreasing towards the centre of an object, but stable, - this should be enough to determinate that the expression; “curvature of space” rather must be understood as “stretching space”, - and hence is the exact same property of space responsible for the “the expanding / stretching Universe”.  Which hence mean; that gravity and the expanding space are united, as it is caused by one and the same property.

The first place such unification “strikes” is that the property responsible for both gravity and the expanding universe can in no way counteract / oppose it self. This off course must mean that space between astronomic bodies must expand too. But since this is not what we observe, the conclusion must be that also space inside matter must expand proportional with the expanding universe. Even the meter-stick also expands proportional with the rest of the Universe; we have no way to prove that everything is expanding with the same rate. (Or in other words; everything expands proportional with its already existing “stretch” factor”).

One more consequence of the unification of gravity and the expanding Universe is that time dilation that applies for gravity (GR) also must comprehend the expanding Universe.

This means that when the universe (and everything in it) was only half the size as now, time was ticking double so fast.  Both time (the second) and distances (the meter stick) has since both been “stretching” proportional, without any direct observable possibility to discover it.

Hence the Cosmologic redshift we see in the EM-spectre is not caused due to the distance-expansion, because 1 meter today, - (is even though it is relative double so big today compared to the example), it is still (only) one meter.

However time would tick half so fast today (compared to the example), because our time (one second) is lasting double so long time, - hence we can now (in our time) also count double so many photon-frequencies per second compared to when the Universe was only the half the size, and time (the second) lasted only half the time, compared to now.

According to the prevailing understanding, it is believed that photon loses energy when travelling through space. It is believed that the energy either disappears or converts to gravity.   But as we can easy see there is no such energy lost, but only time differences.  When we look at light reaching us from distance stars we are not looking back on previous distances,-  but rather we are only looking back in time.

It is also believed that the expansion of the Universe is accelerating, - the so called Dark Energy.   This is a wrong conclusion based on a “optical illusion”, - due to that we not are aware that it rather is the meter-stick that is expanding proportional with the expanding Universe.  Seen in such perspective (the universe is of course expanding) but not accelerating.

From General Relativity we know that time and distances both are “stretching” towards an object.  But because also the meter-stick is stretching proportional, it means that the Mercury orbit anomaly can’t be solved. 

The real cause of the Mercury Anomaly is much more complicated. Inertia is completely misunderstood.   We don’t know why there are resistances against motion (against acceleration) in vacuum. According to this theory it is because matter and space is connected.  Motion of matter is also motion of  space connected to an object. Hence motion disturbs space, and this is the cause of resistance against motion (inertia).  That resistance doesn’t disappear just because constant speed is reached.  Now we may ask; - why does planets then not fall down on the Sun. ?

The answer is;  the same connection between matter and space responsible for inertia, also affects bodies around a rotating astronomic body.  This is a completely new discovery. Read what NASA discovered here.

Inertia and the rotating force of a body counteracts each other..