Final answer:
Greek scientists such as Eratosthenes studied the circumference of the Earth to confirm the belief in a spherical Earth, supported by philosophical and astronomical observations. Eratosthenes used the angle of the Sun's rays to make an accurate measurement of Earth's circumference around 200 BCE.
Step-by-step explanation:
Greek scientists like Eratosthenes studied the circumference of the Earth because the Greeks had a strong understanding that the Earth was spherical, a belief dating back to Pythagoras and later supported by Aristotle. The recognition of Earth's round shape was supported by observations such as the circular shadow during lunar eclipses and the changes in visible stars at different latitudes. Eratosthenes, living in Alexandria, Egypt, used a geometric method based on observations of the Sun to measure the Earth's diameter with remarkable accuracy around 200 BCE. By observing the angle of the Sun's rays at different locations, he was able to estimate the Earth's circumference successfully.
The Greek knowledge of a spherical Earth played a significant role in their philosophical and religious symbolism, and it also had practical implications for understanding celestial motions, as demonstrated by Ptolemy's model of the universe. Despite the complexity of the ancient Greek models and the controversial estimates of Earth's size, the work of scholars like Eratosthenes laid the foundation for future scientific discoveries and navigational methods.