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A flat-Earth has nothing to do with Catholic doctrine or theology so should be kept out of the subject.

What is "the subject" as you see it?

You apparently presume the overall discussion is intended to be essentially or principally theological.  Clearly, this has not been and is not presently the case.  While theology is certainly superior to all of the natural sciences, it is clearly not the only science.

Geocentrism then was fundamental to the dogma of Creation. But Satan knew how to eliminate this supernatural existence of tyhe world. It began with Galileo saying that heliocentrism was a natural truth and that the Bible had been misinterpreted as literal when in fact it was heliocentric. History records a number of discoveries that supposedly 'proved' heliocentrism correct. From 1741 to 1835, churchmen of the Holy Office convinced the popes of the time heliocentrism was proven so they had better take forbidden heliocentric books off the Index. They did this. But taking books off the Index does not remove any heresies in them. Nevertheless this act was interpreted as such and because churchmen thought the Church of 1800 years made a mistake in reading the Bible properly, went no further. This of course meant the doctrine of ages and the papal definitions of 1616 and 1633 were wrong and that is the belief that has been handed on up to our time.

But science continued and it becamne clear that heliocentrism was never proven and the geocentrism of Scriprure and its Catholic doctrine was never shown to be wrong. 

‘Whether the Earth rotates once a day from west to east as Copernicus [and Galileo] taught, or the heavens revolve once a day from east to west as his predecessors believed, the observable phenomena will be exactly the same. This shows a defect in Newtonian dynamics, since an empirical science ought not to contain a metaphysical assumption that cannot be proved or disproved by observation.’ ---  Bertrand Russell: quoted in D. D. Sciama’s The Unity of the Universe, p.18.

Note what Bertrand Russell (1872-1970) and all credible physicists for the last hundred years are saying after 400 years of investigation; that the question seeking to know the order of the world for certain does not belong to natural science as those in Church and State have long claimed, for it is a metaphysical problem. And that is what Pope Paul V defined and declared as heresy in 1616, a question belonging to faith, something beyond human science but not beyond Revelation as described in the Holy Scriptures.

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Note what Bertrand Russell (1872-1970) and all credible physicists for the last hundred years are saying after 400 years of investigation; that the question seeking to know the order of the world for certain does not belong to natural science as those in Church and State have long claimed, for it is a metaphysical problem. 

Metaphysics is a branch of philosophy, the queen of the natural sciences.  What is more, whether we live on a flat plane or on the surface of a sphere can most certainly be deduced via observation. What exactly does the "order of the world" encompass?