There are several proofs to regard the earth as a spherical shape of the Earth.
a. Heavenly bodies appear to be spherical: The Sun, the Moon and other heavenly bodies appear to be spherical when viewed from different position. The earth is one of them and hence it must also be spherical in shape.
b. The Lunar Eclipse: The lunar eclipse proves that the Earth is in spherical shape. During lunar eclipse when the Earth is between the Sun and the Moon, the shadow of the Earth falls on the Moon. Aristotle was the first scholar to show this by looking at the shadow of the Earth on the lunar surface. Later, this was ascertained by Ptolemy. This is considered to be the oldest proof in respect of the shape of the Earth.
c. Sunrise and Sunset: The time of Sunrise and Sunset is not the same everywhere in the world. This is due to spherical shape of the Earth. If the Earth were to be flat all places on the Earth would have had sunrise and sunset at the same time everywhere in the world.
d. Circumnavigation: Circumnavigation of the world can only be possible when the Earth is in spherical shape. If one start on a sea voyage towards the east, by moving constantly in the same direction, he would be able to complete a circle of the world and reach the original point form where he had started.
e. The Bed Ford level experiment: Dr.Alfred Russel Wallace conducted an experiment in 1956, along the Bed Ford level canal area in Britain. It is the most convincing proof of the curvature of the Earth. He fixed three poles of same height at an interval of about mile apart and observed through a telescope. It was found that the pole in the middle was higher than other two poles. It is due to the curvature of the Earth. If the Earth were to be flat all the poles would have the same horizontal level.
f. Sighting a ship: A ship on the sea approaching the coast, when seen from the short does not come into view all at once. The observer first sees the mast and then the hull and finally the whole ship. A ship moving away from the coast disappears gradually and finally out of view. If the Earth were to be flat the whole ship would have come into view.
g. Aerial and Satellite Photographs: The photographs taken by the cosmonauts in the recent decades and satellites have provided ample proof to show that the earth is spherical in shape.
