Ask the Chatbot Games & Quizzes History & Society Science & Tech Biographies Animals & Nature Geography & Travel Arts & Culture ProCon Money Videos
Measuring the Earth, Classical and Arabic
Table of Contents
Introduction References & Edit History
Images
Poseidonius measures the Earth c. 100 bc. Medieval Arabic method of measuring the Earth.
Related Questions
Discover
Cathedrale St.Jean in Lyon, France has a 14th-century astronomical clock that shows religious feast days till the year 2019; Perpetual Calendar
Ten Days That Vanished: The Switch to the Gregorian Calendar
Baseball laying in the grass. Homepage blog 2010, arts and entertainment, history and society, sports and games athletics
10 Greatest Baseball Players of All Time
World Data Locator Map: Australia
Is Australia an Island?
David Cameron. President Barack Obama and Prime Minister David Cameron of the United Kingdom talk during the G8 Summit at the Lough Erne Resort in Enniskillen, Northern Ireland, June 17, 2013
What’s the Difference Between a President and a Prime Minister?
Law legal system crime concept with gavel and scales of justice with books in the background. (mallet, judicial system).
What Are the Differences Between First-, Second-, and Third-Degree Murder?
Aphrodite. Greek mythology. Sculpture. Aphrodite is the Greek goddess of love and beauty.
12 Greek Gods and Goddesses
Young boys working in a thread spinning mill in Macon, Georgia, 1909. Boys are so small they have to climb onto the spinning frame to reach and fix broken threads and put back empty bobbins. Child labor. Industrial revolution
The Rise of the Machines: Pros and Cons of the Industrial Revolution

Measuring the Earth, Classical and Arabic

Feedback
Corrections? Updates? Omissions? Let us know if you have suggestions to improve this article (requires login).
Thank you for your feedback

Our editors will review what you’ve submitted and determine whether to revise the article.

External Websites
Written by
J.L. Heilbron
Senior Research Fellow at the University of Oxford, England. Author of Geometry Civilized and The Sun in the Church among others.
J.L. Heilbron
Fact-checked by
The Editors of Encyclopaedia Britannica
Encyclopaedia Britannica's editors oversee subject areas in which they have extensive knowledge, whether from years of experience gained by working on that content or via study for an advanced degree. They write new content and verify and edit content received from contributors.
The Editors of Encyclopaedia Britannica
Article History

In addition to the attempts of Eratosthenes of Cyrene (c. 276–c. 194 bc) to measure the Earth, two other early attempts had a lasting historical impact, since they provided values that Christopher Columbus (1451–1506) exploited in selling his project to reach Asia by traveling west from Europe. One was devised by the Greek philosopher Poseidonius (c. 135–c. 51 bc), the teacher of the great Roman statesman Marcus Tullius Cicero (106–43 bc). According to Poseidonius, when the star Canopus sets at Rhodes, it appears to be 7.5° above the horizon at Alexandria. (In fact, it is a little over 5°.) The ...(100 of 350 words)

Access the full article
Help support true facts by becoming a member.