Distance to the Moon and Sun (Aristarchus)
Medida de la distancia y tamaño de la Luna y el Sol
- Date
- c. 270 BCE · confidence medium
- Place
- Alexandria, Egypt
- Credited to
- Aristarchus of Samos
- People
- 👤 Aristarco de Samos310 BCE–230 BCE
- Field
- Cosmos & Earth
What was discovered
Using the geometry of eclipses and the phase of the half moon, Aristarchus estimated that the Moon is about 60 Earth radii away (correct) and that the Sun is much larger than the Earth. It was the first attempt to measure the cosmos.
The error in the distance to the Sun (20 times smaller than the real value) was due to the difficulty of measuring the quadrature angle.
What it led to
- Scale of the solar system
- Argument for heliocentrism (the larger body does not orbit the smaller)
- Hipparchus's method for the lunar distance
Built on
Made possible
- Trigonometry applied to astronomy