How did Jupiter’s moons challenge the idea that everything orbited Earth?

The discovery of Jupiter’s moons by Galileo Galilei in 1610 provided a critical challenge to the Ptolemaic system, which was the prevailing geocentric model of the time.

Under the Ptolemaic system, it was believed that all celestial objects were required to orbit Earth, which was considered the unique center of the universe. By observing four satellites revolving around Jupiter, Galileo demonstrated that there were multiple centers of motion in the universe. This observation directly contradicted the Aristotelian and Ptolemaic assumption that Earth was the sole point around which all heavenly bodies moved.12

Consequently, these findings served as a fundamental argument in favor of the Copernican model, which posited that the planets orbit the Sun. By proving that other planets could possess their own orbiting satellites, Galileo effectively demoted Earth from its unique, central position in the cosmos.132