Galileo Galilei

1564 – 1642

Nicolaus Copernicus publishes his theory that the Earth orbits the Sun, directly challenging the Church-backed Ptolemaic system. His model triggers the Scien…

• 1543 CE

  Copernicus proposes heliocentric model

  Nicolaus Copernicus publishes his theory that the Earth orbits the Sun, directly challenging the Church-backed Ptolemaic system. His model triggers the Scientific Revolution—a fundamental shift in how Europeans understand nature, authority, and the cosmos.

• 1609 CE

  Galileo turns telescope on the sky

  Galileo Galilei points his improved telescope at the heavens and discovers Jupiter's moons, mountains on the Moon, and the phases of Venus. His observations confirm the Copernican model—and lead to his trial by the Inquisition, a defining clash between science and religious authority.