Astronomers, in their consideration of the supposed "curvature" of the Earth, have carefully avoided the taking of that view of the question which - if anything were needed to do so -would show its utter absurdity. It is this: - if, instead of taking our ideal point of departure to be at Valentia, we consider ourselves at St. John's, the 1665 miles of water between us and Valentia would just as well "curvate" downwards as it did in the other case! Now, since the direction in which the Earth is said to "curvate" is interchangeable - depending, indeed, upon the position occupied by a man upon its surface - the thing is utterly absurd; and it follows that the theory is an outrage , and that the Earth does not "curvate" at all: - an evident proof that the Earth is not a globe.
Imagine an ant walking along the surface of an orange, into your field of view. If you look at the orange “head on”, you will see the ant’s body slowly rising up from the “horizon” because of the curvature of the orange. If you would do that experiment with the ant approaching along a long road rather than a round object, the effect would change: The ant would slowly "materialize" into view (depending on how sharp your vision is).
As mariners take to sea with them charts constructed as though the sea were a level surface, however these charts may err as to the true form of this level surface taken as a whole, it is clear, as they find them answer their purpose tolerably well - and only tolerably for many ships are wrecked owing to the error of which we speak - that the surface of the sea is as it is taken to be, whether the captain of the ship "supposes" the Earth to be a globe or anything else. Thus, then, we draw, from the common system of "plane sailing," a practical proof that Earth is not a globe.
The most commonly accepted explanation of this is that the space agencies of the world are involved in a conspiracy faking space travel and exploration. This likely began during the Cold War's 'Space Race', in which the USSR and USA were obsessed with beating each other into space to the point that each faked their accomplishments in an attempt to keep pace with the other's supposed achievements. Since the end of the Cold War, however, the conspiracy is most likely motivated by greed rather than political gains, and using only some of their funding to continue to fake space travel saves a lot of money to embezzle for themselves.