Throughout history this issue has been more than discussed. Classical Greece already spoke of the sphericity of the Earth, even Eratosthenes came to measure the radius of it by a process of trigonometry comparing the length of the shadow of two objects of equal height at the same time and knowing the distance that the To stop. On the contrary, there are several theories about the flatness of the Earth, from Christian in the Middle Ages and later to Greek in origins. Finally when the Spanish sailor Juan Sebastián Elcano concluded the return to the world it was accepted completely (or apparently not) that the Earth was round.
Here I have to make a parenthesis to emphasize the difference between the Earth being round or spherical. The Earth can be assimilated to a sphere, although its dimensions are not perfect, we can speak of sphere without problem; However, some people maintain that it is flat but round, that is, as if a globe had been crushed, with what would resemble an ellipsoid.
At this time certain people defend the latter, specifically there is an American association, "The Flat Earth Society." In 1956 Mr. Samuel Shenton member revived these theories that had been spread in the US by sects, who interpreted the Bible personally. A few years later Shenton died leaving the presidency of the society to Charles K. Johnson who was the one who really has strengthened this theory, reaching in the following years up to 3000 followers enrolled in the society.
The last model shown by these people about what the Earth really looks like shows the North Pole at the center of a circumference surrounded by continents and whose perimeter is a 45 meter high ice wall. He also adds that the Sun's diameter is less than 52 km when it really measures 1,391,000 km.
And now it is when one raises a multitude of questions to this theory. How is it that no one has reached the edge of the circumference that these people maintain is an ice wall? And the images that have been taken from our planet from space? In this regard Mr. Shelton argued that these photos evidently showed the terraplanismo but that to an inexperienced eye can give the sensation that it is a sphere, then Why do images exist from different angles? And above all, why does the North Pole not appear in the middle?
To all this is added the theory of plate tectonics, the tides, the earth's magnetic field, the force of gravity, the satellites that orbit around the Earth due to the latter, in addition to the studies of the universe carried out in the last 60 or 70 years.
In short, we can say that this is a totally false theory, with very low scientific level, to say nothing, and that having a couple of followers already has too many. Not so many years ago, this theory was used, as I said before, for sectarian purposes that terraplanism took advantage of to attract people who did not have things very clear. This sect reached 6,000 followers in a congregation located in Illinois and directed by Wilbur Glenn Voliva who used them as forced laborers. When dying this in the year 41 the sect broke up among multiple financial scandals.
@samue2013