Unknown.
Come on Tom! You can do better than this. You are one of the most vocal proponents of FE theory making valid predictions.
Seems to me that one of the most important tenets of FE theory would be able to make predictions on how everything, other than the FE, is affected by the force which keeps everything in place on the FE.
We work from experiment to experience here. We have standards. Whatever keeps the sun up is not testable or observed, and making a prediction of something so beyond the range of human experience is antithetical to the empirical tenets of Zeteticism, and is more in line with Round Earth ramblings about gravitons and black matter.
Please carefully explain to me what "gravitons and black matter" might have to do with
the shape of the earth! If you want to know the shape of something - measure it!
The shapes of the countries on earth have been measured with nice solid old fashioned things like surveyor's chains and theodolites (no GPS or electronics) and the
real shapes of countries is vastly different from
those on any map you have proposed. Please list the "experiment to experience" that provides any evidence that Newtonian Gravitation is false and that what we call gravity is actually caused by Universal Acceleration.
With so many things The Flat Earth Society seem to simply hypothesise something, the bend (sometimes literally) everything else to fit. No-one has yet provided any evidence of how moon phases or eclipses can actually work with your model. All you say is that the behaviour of light (or perspective) over long distances is unknown, yet never give evidence. In particular the "small (5 to 10 miles, I believe) shadow object" explanation of the lunar eclipse is
completely impossible.
I have provided reference numerous times that Newtonian Gravitation has been verified and measured, but that has been completely ignored!
Not only that, but the Newtonian Laws of Motion and Gravitation provided a very good explanation of the orbital periods of our moon and the planets.
While the simple orbital calculation are based on simple two-bodied systems, the results are still quite close to the observed values.
The distance computed from these laws agrees for at least our moon and Venus compares well with that measured directly by radar and more recently for the moon by laser methods.
Still, I guess you must follow the infallible word of Rowbotham!