James,
Since you asked, here is my opinion. Instantaneous action at a distance is a fact of solar system orbital dynamics, and few people even attempt to explain the mechanism. I do not believe the influence of gravity has infinite speed, it just appears so in the short distances of our solar system. When I look at a spiral galaxy, I see how our planetary orbits would look like if the influence of gravity wasn't essentially instant within solar system distances.
Some researchers have measured unexplained superluminal velocities in the near and far-field in electromagnetic (EM) propagation experiments. The Walker-Dual and Van Flandern articles get a lot of attention, but anomalous superluminal velocities were reported in papers by Ishii-Giakos in IEEE publications. A recent paper by Hively and Giakos in the International Journal of Signal and Imaging Systems Engineering (IJSISE), Volume 5 - Issue 1 - 2012, revisited the superluminal issue.
Toward a more complete electrodynamic theory
The following quote from the article should get more attention: "A non-decaying longitudinal B-wave was observed, as shown in Fig. 3. This result follows from classical electrodynamics in conversion of the wave-guide modes to low-loss free-space propagation, see Giakos and Ishii (1993) and references therein. The observed longitudinal components do not decay according to the 1/R2 or 1/R3 with distance, but at a much slower rate."
The orientation of the electrical and magnetic field vectors of light are transverse to the axis of propagation, thus they cannot present a force in the direction of propagation irrespective of how matter interacts with light, unless something can translate the fields to a different orientation. An electromagnetic wave that has one field aligned with the axis of propagation could be described as being longitudinally polarized. Optical researchers have actually produced photons with longitudinal field components, and these "L-photons" (newly coined term) are being exploited as optical tweezers in commercial devices.
Your essay proposes that light photons are being altered to produce the force of gravity. I think you are close, but I think something like a L-photon is producing the gravity force, and it might even look like light. L-photons are detected using the same type detectors used for normal transverse field light photons.
There were three assumption issues I considered for this essay contest, units of measure, the vacuum of space, and gravity. I have no publications supporting my views on the vacuum of space or gravity, but I do have an IEEE published article that describes how units of measure can be mathematically defined, thus, I went with that essay issue. I have an unpublished paper that describes how gravity propagates at what is termed the speed of light, and I provide a simple explanation, and the mechanism, how the influence of gravity is superluminal, once propagated.
Your essay article breaks with the current assumption about the force of gravity, and I agree the current assumption is erroneous. However, any presentation of a new gravity theory has to consider the Newtonian gravity instantaneous influence at a distance, at least within solar system distances.