Astronomer — Tycho Brahe (Knutstorp 1546 – Prague 1601) was a Danish astronomer, the greatest naked-eye observer of the pre-telescopic era. Noble by birth, he obtained from the King of Denmark the island of Hven, where he built the observatory of Uraniborg, equipped with measuring instruments of unprecedented precision. For decades he gathered systematic and highly accurate data on the positions of planets and stars, with errors reduced to a few arcminutes. He proposed an intermediate system of the world (Tychonic), with the Earth fixed at the centre but the other planets orbiting the Sun. Having moved to Prague, he took on Kepler as an assistant, whose data allowed Kepler to derive the laws of planetary motion.

Theories and contributions

  • Precision astronomical observations — The most accurate catalogue of planetary and stellar positions obtained by naked eye, the basis of Kepler’s laws.
  • Tychonic system — Geo-heliocentric model: the Earth is motionless at the centre, the Sun orbits it, and the planets orbit the Sun.
  • Nova of 1572 — The observation of a new star showed that the heavens were not immutable, against Aristotelian cosmology.

Linked atoms

2 linked atoms.

08 Gravitazione universale