Final answer:
There is overwhelming evidence that supports the idea that the Earth is a spherical shape. Philosopher and mathematician Pythagoras proposed that Earth must be a sphere because circles and spheres are considered perfect forms. Aristotle observed that during a lunar eclipse, the shadow cast by Earth on the Moon is always round, which is consistent with a spherical shape.
Step-by-step explanation:
There is overwhelming evidence that supports the idea that the Earth is a spherical shape. Belief in a round Earth dates back at least 2000 years before Christopher Columbus. Philosopher and mathematician Pythagoras proposed that circles and spheres are perfect forms, suggesting that Earth must be a sphere. The Greeks also pointed to the fact that the Moon is a sphere as evidence for Earth's spherical shape.
An additional argument for a spherical Earth comes from Aristotle, who observed that during a lunar eclipse, the shadow cast by Earth on the Moon is always round. This is consistent with the behavior of a spherical object casting a round shadow. If Earth were flat, there would be times when the shadow on the Moon would appear as a line rather than a circle.
In summary, the evidence includes historical and philosophical beliefs, as well as observation of a round shadow during an eclipse. These factors strongly indicate that the Earth is indeed spherical.