Who is known as the father of geography and astronomy?

• A. Ptolemy
• B. Hipparchus
• C. Eratosthenes
• D. Aristarchus

Answer: (C)

Eratosthenes is celebrated for establishing geography as a systematic study by combining careful measurement with mapmaking. He showed how astronomy and geography work together: by observing how the sun’s rays hit two places at the same time, he used that celestial observation to infer the Earth’s size. In Syene, the sun was effectively overhead at noon, while in Alexandria it cast a measurable angle. By measuring that angle and knowing the distance between the two cities, he estimated the Earth’s circumference with impressive accuracy for his time. This method demonstrates how understanding the heavens can illuminate our view of the Earth, a core idea in geography, and it also anchors early astronomical reasoning in practical, measurable evidence. Because of these pioneering approaches—mapping the world with geometry and tying celestial observations to geographic knowledge—he is commonly regarded as the founder of geography, with his work also resonating in early astronomy.