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Gravity Two models are needed as the background for each is different.
1.Einstein /Minkowski curved space-time fabric corresponds to what we see, by the process of vision. It is a perdurant model in which matter bodies / objects and background are spread over time due to vision being possible because of photon particles being transmitted and the photon particles being delayed by gravity, affecting time of receipt.
The other model pertains to actual matter, existing wholly-Now. That can’t be seen. We see 1. This is an endurant model. Objects and background exist wholly at -Now. Their existing is not spread over time. Here we can use Newtonian gravity,which doesn’t take notice of time. matter with gravity affects other matter atracting it and particles if matter in the environment, non matter-bound particles in the environment (plasma) and other space filling substance, through which light is transmitted. In this model rather than having a constant speed of light assuming the vacuum of apace to be everywhere a vacuum,. objects of matter are affected by the density of what they pass through, the more dense the more light slows and bends casing refraction.
Space that we think of as empty may not be. It may contain matter, or non matter-bound particles or gravitationally significant other unseen substance. This could be the elusive dark matter ,which is hypothesized to exist but is absent from most models.