celeste wrote: a gravitational field ( whatever that means)

Indeed... A defined space in which the effects of gravitation may be observed and measured by the interaction of contained objects -- ie. the universe, at every level or hierarchy.

Gravitation, as the patriarchs of science understood, is the propensity of stuff in the universe [and by extension, the universe itself] to stick together. No doubt it is an electrical action as well as a stellar one. And the best models for gravitation are geometric. Sticking together is a colloquialism for compression, or pressure, so it is apt to describe gravitational action with vectors. Visualizing gravitation as pressure, rather than as imagined gravitons or waves, directs us to consider ray diagrams to describe the interactions of moving bodies, as in orbital vectors, voltage and charge, "current", Poynting vectors, etc.; leading to the recognition that optical ray diagrams are also representing [a part of] the bigger picture of the UNIverse. Unifying the various "gravitational" pressures through geometry leads to a satisfying, though not yet complete, therefore challenging pursuit of a theory of everything without recourse to phantasmic black holes, WIMPS, probabilistic uncertainties/dualisms or transformations [Lorentz. et.al.], warpage of space and time, etc. ... just rambling...

Centropic Pressure Field Theory