Book:Aristarchus of Samos/On the Sizes and Distances of the Sun and Moon

Subject Matter

 * Astronomy

Contents
A deduction that the Sun lies about $18$ to $20$ times as far away from Earth as does the Moon.

His method was correct, but his measurements were inaccurate.

The actual value is more like $400$.

However, this was an improvement over the estimate of, who argued for $10$.