• Skip to primary navigation
  • Skip to main content
  • Skip to footer
Zippy Facts Logo

Zippy Facts

Interesting Random Facts

  • Animals
  • Culture
  • Firsts
  • Food
  • Geography
  • Health
  • History
  • Inventions
  • Language
  • Mythology
  • Odds
  • People
  • Religion
  • Science
  • Space
  • Universe
  • World
You are here: Home / Odds / How did the Greeks know the size of the earth over 1,700 years before anyone sailed around it?

How did the Greeks know the size of the earth over 1,700 years before anyone sailed around it?

February 9, 2020 by Karen Hill

In the third century B.C., Eratosthenes needed no more than a gnomon, or shadow stick, to measure the whole earth, and his answer missed our contemporary, sophisticated measurements by only 5 percent.

On the summer solstice, Eratosthenes stood at Alexandria with his gnomon. When the sun reached its zenith over Syene, a city 5,000 stades, or 527 miles, due south of Alexandria, he measured the length of the shadow cast by his stick.

At Alexandria the angle of the sun was 7°12′ away from its zenith. From this observation and knowledge of the distance to Syene, he calculated the earth’s circumference as 250,000 stades, or 26,350 miles.

The actual polar circumference, according to scientists today, is 24,859 miles.

Related Facts

  • How Did the Greeks Figure Out the Size of the Earth?
  • How Did Pat Robertson's Television Show "The 700 Club" Get its Name and What Does it Mean?
  • Where does the word "size" (assize) come from and What does size mean in French?
  • Did Christopher Columbus have any children when he sailed to America?
  • Who captained the Pilgrim ship the Mayflower when they sailed to Plymouth, Massachusetts?
  • How did the Greeks and Romans figure out that the earth is round not flat?

Filed Under: Odds

About Karen Hill

Karen Hill is a freelance writer, editor, and columnist. Born in New York, her work has appeared in the Examiner, Yahoo News, Buzzfeed, among others.

Previous Post: « How and why did the people of France kill Marie Antoinette?
Next Post: How did Congress determine the membership of the U.S. Senate during the 1700s? »

Footer

Follow

  • Facebook
  • Flickr
  • GitHub
  • Google+
  • Instagram
  • LinkedIn
  • Medium
  • Pinterest
  • StumbleUpon
  • Tumblr
  • Twitter
  • YouTube

Categories

Accomplishments Animals Culture Firsts Food Geography Health History Inventions Language Mythology Odds People Religion Science Space Universe World Your Body

About

Zippy Facts empowers the world by serving educational content that is accessible to everyone.

A tribute to growing up, zippyfacts.com showcases interesting and unusual facts about the world.

Our mission is to use technology to facilitate knowledge transfer and sharing.

Copyright © 2021 Zippy Facts

  • About Us
  • Contact
  • Privacy Policy