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ERIC Number: EJ959250
Record Type: Journal
Publication Date: 2011-May
Pages: 8
Abstractor: As Provided
Reference Count: N/A
ISSN: ISSN-0746-8342
Newton's Radii, Maupertuis' Arc Length, and Voltaire's Giant
Simoson, Andrew J.
College Mathematics Journal, v42 n3 p183-190 May 2011
Given two arc length measurements along the perimeter of an ellipse--one taken near the long diameter, the other taken anywhere else--how do you find the lengths of major and minor axes? This was a problem of great interest from the time of Newton's "Principia" until the mid-eighteenth century when France launched twin geodesic expeditions--one to the equator near Quito, the other to the Finnish arctic led by Maupertuis--so as to determine whether the earth was lemon-shaped, as the French Academy long contended, or like a mandarin orange as Newton promised. We give a simplified version of Newton's argument, and show how an elliptical profile model for the earth's shape together with an arc length measurement determines the amount of flattening of the earth at the poles. We conclude by speculating why Voltaire made his giant Micromegas exactly 23 miles tall.
Mathematical Association of America. 1529 Eighteenth Street NW, Washington, DC 20036. Tel: 800-741-9415; Tel: 202-387-5200; Fax: 202-387-1208; e-mail:; Web site:
Publication Type: Journal Articles; Reports - Descriptive
Education Level: Higher Education
Audience: N/A
Language: English
Sponsor: N/A
Authoring Institution: N/A
Identifiers - Location: Finland; France