How did Galileo Galilei support the Copernican heliocentric model?

Galileo Galilei supported the Copernican heliocentric model through critical telescopic observations that challenged the prevailing Ptolemaic system and Aristotelian cosmology.123

His primary contributions included:

• Discovery of Jupiter’s Moons: In 1610, Galileo observed four moons revolving around Jupiter. This provided evidence that not all celestial bodies orbited the Earth, demonstrating that there could be multiple centers of motion in the universe.123
• Phases of Venus: Galileo discovered that Venus exhibits a full cycle of phases similar to the Moon. This observation provided direct evidence that Venus revolves around the Sun, ruling out the traditional Ptolemaic model where Venus remained between Earth and the Sun.124
• Public Advocacy: He popularized these ideas in his 1632 work, Dialogue Concerning the Two Chief World Systems, Ptolemaic & Copernican, where he presented arguments favoring the Copernican view.2

These findings were foundational to the Scientific Revolution, as they undermined the belief in an Earth-centered universe and provided empirical support for a heliocentric solar system.14