# How did the Greeks work out the circumference of the earth?

## How did the Greeks work out the circumference of the earth?

Eratosthenes hired a man to pace the distance between the two cities and learned they were 5,000 stadia apart, which is about 800 kilometers. He could then use simple proportions to find the Earth’s circumference — 7.2 degrees is 1/50 of 360 degrees, so 800 times 50 equals 40,000 kilometers.

## Why was determining the circumference of the earth so important?

Measurement of Earth’s circumference has been important to navigation since ancient times. The first known scientific measurement and calculation was done by Eratosthenes, who achieved a great degree of precision in his computation. Earth deviates from spherical by about 0.3%, as characterized by flattening.

What helped shape ancient Greece?

The geography of the region helped to shape the government and culture of the Ancient Greeks. Geographical formations including mountains, seas, and islands formed natural barriers between the Greek city-states and forced the Greeks to settle along the coast.

### What was the technique used by ancient Greek to measure the relative size of the Earth?

A century after Eratosthenes, the Greek astronomer Posidonius of Rhodes (c. 135–51 BCE) calculated the Earth’s circumference. Posidonius used the star Canopus as frame of reference: when the star is visible at the horizon in Rhodes, it is 7.5 degrees above the horizon in Alexandria.

### Who first discovered the size of the Earth?

Eratosthenes of Cyrene
The first person to determine the size of Earth was Eratosthenes of Cyrene, who produced a surprisingly good measurement using a simple scheme that combined geometrical calculations with physical observations. Eratosthenes was born around 276 B.C., which is now Shahhat, Libya.

How did the ancient Greeks determine the circumference of the Earth?

In the mid-20th century, we began launching satellites into space that would help us determine the exact circumference of the Earth, 40,030 km. But over 2,000 years earlier in ancient Greece, a man arrived at nearly that exact same figure by putting a stick in the ground. That man was Eratosthenes.

## How did Eratosthenes come up with the circumference of the Earth?

In the mid-20th century we began launching satellites into space that would help us determine the exact circumference of the Earth: 40,030 km. But over 2000 years earlier, a man named Eratosthenes in Ancient Greece came up with nearly the exact same figure using just a stick and his brain.

## How did Aristotle measure the circumference of the Earth?

Therefore, 1 stadia is 300 cubits which is 157.5 meters which is about 516.73 feet. Therefore, Aristotle had the Earth’s circumference at about 39,146 miles, assuming this was the stadia he referenced.

When did man find the circumference of the Earth?

And just like that, a man 2200 years ago found the circumference of our entire planet with just a stick and his brain. This video was produced by Alex Kuzoian. This video was originally published on July 3, 2016.