Phases of Venus
Fases de Venus
- Date
- 1610 · confidence high
- Place
- Florence, Grand Duchy of Tuscany, Italy
- Credited to
- Galileo Galilei
- People
- 👤 Galileo Galilei1564–1642
- Field
- Cosmos & Earth
What was discovered
Galileo observed that Venus shows a complete cycle of phases, impossible under the Ptolemaic system: Venus had to orbit the Sun.
Benedetto Castelli suggested the observation; Galileo announced it through an anagram.
What it led to
- Empirical refutation of Ptolemaic geocentrism
- Acceptance of the Tychonic or Copernican system