The Two Earths of Eratosthenes
Bibliographic Data
| ID | 4176021 |
|---|---|
| Authors | Christián C Carman (0000-0002-9022-0765, National University of Quilmes), James Evans (0000-0002-7721-4782) |
| Year | 2015 |
| Volume | 106 |
| Issue | 1 |
| Pages | 1-16 |
| Publication date | 2015-03-01 |
| Open Access | No |
| Type | ARTICLE |
| Venue | Isis (JOURNAL) |
| Journal identifiers | ISSN: 0021-1753 • E-ISSN: 1545-6994 |
| Publisher | University of Chicago Press (PUBLISHER • US) |
| DOI | 10.1086/681034 |
| PMID | 26027305 |
| OpenAlex | W1975421703 |
| Language | EN |
| Citations received | 5 |
| References cited | 13 |
In the third century B.C.E., Eratosthenes of Cyrene made a famous measurement of the circumference of the Earth. This was not the first such measurement, but it is the earliest for which significant details are preserved. Cleomedes gives a short account of Eratosthenes' method, his numerical assumptions, and the final result of 250,000 stades. However, many ancient sources attribute to Eratosthenes a result of 252,000 stades. Historians have attempted to explain the second result by supposing that Eratosthenes later made better measurements and revised his estimate or that the original result was simply rounded to 252,000 to have a number conveniently divisible by 60 or by 360. These explanations are speculative and untestable. However, Eratosthenes' estimates of the distances of the Sun and Moon from the Earth are preserved in the doxographical literature. This essay shows that Eratosthenes' result of 252,000 stades for the Earth's circumference follows from a solar distance that is attributed to him. Thus it appears that Eratosthenes computed not only a lower limit for the size of the Earth, based on the assumption that the Sun is at infinity, but also an upper limit, based on the assumption that the Sun is at a finite distance. The essay discusses the consequences for our understanding of his program
Circumference · Geodesy · Geometry · Infinity · Limit (mathematics · Mathematical analysis · Physics · Geology · Historical and Literary Studies · Historical Astronomy and Related Studies · History and Theory of Mathematics · Mathematics · Philosophy
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| Citations per year | 0.71 |
|---|---|
| Citation span | 2019 - 2024 (6) |
| Highly cited | No |