Shape of Our Earth

In ancient times, approximately thousands of years before Christ, most people assumed that our earth was in the form of a flat disc, where the sun, moon and stars were considered to rise from one end of the earth and set at the opposite end of the earth. Then, in the Middle Ages, some people proved that our earth was in the form of a solid sphere, where this assumption succeeded in modeling the difference between day and night, solar eclipses, and lunar eclipses convincingly. In this model, the earth, moon, and sun are three celestial bodies in such a way that they are able to show how the difference between day and night, solar eclipses, and lunar eclipses occur, with the assumption that sunlight travels straight or almost straight in all directions. In this solid sphere earth model, there are two poles, namely the north pole and the south pole, where at the north pole, there is the Arctic Ocean, while at the south pole, there is the Antarctic Continent. In this model, the local gravitational field lines are roughly radial towards the center of the solid sphere earth. Then, at the beginning of the twenty-first century AD, some people tried to assume that the surface of our earth is a very wide expanse in the form of a circular disc, where the Arctic Ocean is located in the middle of the disc, while the Antarctic Continent is located on the edge of the disc. In this assumption, the moon which is in the form of a solid sphere is located above the flat earth at a certain distance and rotates at the same height, while the sun which is in the form of a solid sphere with a size almost the same as the size of the moon is located above the flat earth at a certain distance that is further than the distance between the earth and the moon and rotates at the same height. The mechanism of the movement of the moon and the sun, as well as the propagation of light rays is such that it is able to show how the difference between day and night, solar eclipses, and lunar eclipses occur. In this assumption, the local gravitational field lines are roughly vertical towards the flat surface of the earth. So, which assumption is correct? Is it the assumption that the earth is in the form of a solid sphere that was put forward by some people in the middle of the AD century or the assumption that the earth is in the form of a circular disc expanse that was put forward by some people in the early twenty-first century AD? Both of these assumptions are equally capable of showing the difference between day and night, solar eclipses, and lunar eclipses, but the difference lies in the shape of the Antarctic Continent. If at some point in the future, there is an airplane that continuously flies south, but eventually the airplane returns to its original place, then it is proven that our earth is a solid sphere. However, the opposite is true. If at some point in the future, there is an airplane that continuously flies south, but the airplane does not return to its original place, then it is proven that the surface of our earth is a flat circular disk. Of course, adhering to the belief that the earth is a solid sphere is much easier than adhering to the belief that the earth's surface is a flat disk, because according to the belief that the earth is a solid sphere, the path of light rays is in a straight or almost straight line, while according to the belief that the earth's surface is in a flat disk, the path of light rays is curved in such a way that it is able to show the difference between day and night, solar eclipses, and lunar eclipses.

This is actually a common misconception.

Yes, some ancient civilisations assumed Earth was flat. But the Ancient Greeks figured out it was round, still in BCE.

The modern FE movement, which shares almost no similarity to the ancient FE models, was revived long before the 21st century.
For example, the FE high prophet Samuel Rowbotham, also known as Parallax, started promoting it in the early 1800s.

The modern FE models typically don't have gravity (but some do). And I am yet to here a convincing explanation for why there is day and night on such a flat Earth. The best I get is handwavy vague nonsense.

Of course, adhering to the belief that the earth is a solid sphere is much easier than adhering to the belief that the earth's surface is a flat disk, because according to the belief that the earth is a solid sphere, the path of light rays is in a straight or almost straight line, while according to the belief that the earth's surface is in a flat disk, the path of light rays is curved in such a way that it is able to show the difference between day and night, solar eclipses, and lunar eclipses.

Actually its easier to believe that things do not naturally travel in straight lines, considering that this is what occurs with all other trajectories and phenomena.

You are starting with an undemonstrated axiom. Large scale straight line light paths are a fantasy fiction which have zero evidence, contrived solely to describe the "perfect" model of the cosm.

Even the official Round Earth Theory states that when you view the sun on the horizon at sunset that the real geometric sun is already fully beneath the horizon. It postulates that you are viewing a false sun when you look a the sunset. In the standard RE model we already have false suns which cannot be easily identified as false. So your incredulity over false suns is discredited.

It makes me sad that Robert Scott died after reaching the south pole only to have some people now question that he did not actually go there.
We do not know how long ago people first came to realize the earth was a sphere, but as Jack Black points out, they knew it hundreds of years before Christ. The Germanic tribes that fought the Romans were illiterate and we have no record of what they believed or thought, as an example. Anyway, the Greeks hundreds of years before Christ noticed that the sun would sometimes shine down to the bottom of a well near the solstice and not other times. They noted that the sun was at a different angle at different latitudes on the same day. Using this difference, Eratosthenes was able to calculate the circumference of the Earth to an accuracy close enough for any practical purpose you or I would need, hundreds of years before Christ. Not a thousand years later.
Anyone who works for a company that ships products over any ocean knows the earth is spherical. Anyone tasked To ship something (or to fly) to some place like Sydney Australia from New York, would be super pissed off if transport companies were idling their ships (or flying in circles) to make sure the trip took the same amount of time going one route versus another. If one airline decided to go against the conspiracy and fly people directly than how the conspiracy would require in a flat earth, that airline would make a killing. Why would the USA agree to look the fool during the early days of the space race if it was all a hoax?
Richard Byrd flew over the South Pole in 1926. What are you waiting for to not just accept reality and not the stupid stuff that liars propose?
How could anyone say that there is some question that the earth is not a sphere if they just think about it for about a minute. Go outside and look at how the sun, moon and stars move. And again I understand that some people have broken backs and cannot get to a window and will believe some foolishness, but the rest of us should not be limited by these (or mental) constraints.

Cheers

You are starting with an undemonstrated axiom. Large scale straight line light paths are a fantasy fiction which have zero evidence, contrived solely to describe the "perfect" model of the cosm.

If light doesn't travel in a straight line over long distances, doesn't that contradict the FE mantra of "it must be flat because it looks flat"?

Actually its easier to believe that things do not naturally travel in straight lines, considering that this is what occurs with all other trajectories and phenomena.

It is much easier to believe that in the absence of an external influence, things travel in straight lines, as there is no preferred directionality.
Having a preferred directionality is special.
And that means it should have a reason for that directionality.

When we see curved or bent paths, there is a reason behind it.
For example, when light refracts, this is because it passes from a substance with one refractive index into another.
That can be a sudden kink in the path for an abrupt change, or a smooth curve from a gradient.