Table of Contents
Who first calculated the circumference of the earth?
The Greek philosopher Aristotle (384-322 B.C.) is credited as the first person to try and calculate the size of the Earth by determining its circumference (the length around the equator) He estimated this distance to be 400,000 stades (a stadia is a Greek measurement equaling about 600 feet).
Who determined the circumference?
Eratosthenes
Eratosthenes erected a pole in Alexandria, and on the summer solstice he observed that it cast a shadow, proving that the Sun was not directly overhead but slightly south. Recognizing the curvature of the Earth and knowing the distance between the two cities enabled Eratosthenes to calculate the planet’s circumference.
How did Aristotle calculate the circumference of the earth?
By measuring the length of the shadow in Alexandria at noon on the Summer Solstice when there was no shadow in Syene, he could measure the circumference of the Earth! At Syene: The Sun is directly overhead, no shadows are cast at that moment.
How long is Earth’s circumference?
40,075 km
Earth/Circumference
What is polar circumference of Earth?
Earth’s polar radius is 3,950 miles (6,356 km) — a difference of 13 miles (22 km). Using those measurements, the equatorial circumference of Earth is about 24,901 miles (40,075 km). However, from pole to pole — the meridional circumference — Earth is only 24,860 miles (40,008 km) around.
Why was the circumference of the Earth first measured?
Measurement of Earth’s circumference has been important to navigation since ancient times. The first known scientific measurement and calculation was first calculated by Eratosthenes, which he did by comparing altitudes of the mid-day sun at two places a known north–south distance apart.
Who first measured the radius of Earth?
Earth’s circumference was first accurately measured more than 2,000 years ago by the Greek astronomer Eratosthenes, who at the time lived in the Egyptian city of Alexandria.
Who was the first person to accurately measure the Earth’s tilt?
Eratosthenes is considered the inventor geography, particularly because he developed the system of latitudinal and longitudinal lines to map the world. He calculated the Earth’s tilt with remarkable accuracy, but also inaccurately measured the distance between Earth and the Moon.
How did Eratosthenes calculate the size of the Earth?
Because seven degrees is about one 50th of a full circle (360 degrees), Eratosthenes simply multiplied the distance from Alexandria to Syene — believed to have been about 515 miles (830 km) — by 50. He calculated Earth’s circumference at 26,000 miles (42,000 km), only five percent away from the modern accepted value of 24,901 miles (40,074 km).