# How the circumference of the Earth was first calculated?

## How the circumference of the Earth was first calculated?

Eratosthenes then measured the angle of a shadow cast by a stick at noon on the summer solstice in Alexandria, and found it made an angle of about 7.2 degrees, or about 1/50 of a complete circle. He realized that if he knew the distance from Alexandria to Syene, he could easily calculate the circumference of Earth.

## How did Ptolemy calculate the circumference of the earth?

Ptolemy made a similar geometric estimate based on stellar (rather than solar) measurements made earlier by Marinus of Tyre (by way of Posidonius). This estimate yields a circumference of 28,800 kilometers, which is ~28% smaller than the correct circumference (40,070 km).

How do you calculate the circumference of the earth?

Eratosthenes sent a man to Syene from Alexandria on foot to measure the distance between Alexandria and Syene. Thus, Eratosthenes measured the distance between the two cities is 800 km. He multiplied by 800 km to 50 and calculated that the Earth’s circumference is 40,000 km.

What is the circumference of the earth?

24,901 mi
Earth/Circumference

### What is the circumference of the earth according to Aristotle?

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).

### What is the formula of Earth?

It would take you almost 17 days driving at 100 km/hour, 24 hours a day to complete that journey. If you like, you can calculate the Earth’s circumference yourself. The formula for calculating the circumference of a sphere is 2 x pi x radius. So, the radius of the Earth is 6371 km.

How was the Earth measured?

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. On the day the Sun shone on the bottom of the wells in Syene, Eratosthenes measured the Sun’s position in the sky over Alexandria.

What does the Earth weigh?

5.972 × 10^24 kg
Earth/Mass

## How to calculate the circumference of the Earth step by step?

That angle, 7.2°, is 1/50 of a complete circle: So, if 804 km or 500 mi. (or 5,000 stadia for Eratosthenes) was 1/50th, multiplication gives you the earth’s circumference:

## Who was the first person to measure the circumference of the Earth?

In Egypt, a Greek scholar and philosopher, Eratosthenes (276 BCE – 195 BCE) measured Earth’s circumference with great precision. He estimated that the meridian has a length of 252,000 stadia, with an error on the real value between -2.4% and +0.8% (assuming a value for the stadion between 155 and 160 metres).

How did Eratosthenes calculate the circumference of the Earth?

Eratosthenes described his technique in a book entitled On the measure of the Earth, which has not been preserved. Eratosthenes’ method to calculate the Earth’s circumference has been lost; what has been preserved is the simplified version described by Cleomedes to popularise the discovery.

What is the circumference of the Earth around the equator?

Measured around the Equator, it is 40,075.017 km (24,901.461 mi). Measured around the poles, the circumference is 40,007.863 km (24,859.734 mi). Measurement of Earth’s circumference has been important to navigation since ancient times.