system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: How did people begin to disprove the geocentric model?
gpt
Early evidence: the visible planets follow bizzare paths across the sky that are difficult to explain with the Earth at the center.  Mercury and Venus never leave the Sun's proximity, the others lazily wander through the sky on multi-year cycles that confounded early astronomers.

Eventually (1500s) telescopes got good enough to resolve details about the planets, and astronomers noted that Jupiter had objects that seemed to orbit it instead of Earth and that Venus went through distinct moon-like phases.

This suggested that Venus was orbiting the sun and not simply moving in some bizzare path ahead or behind it, and that it was possible for objects to orbit other things.

Taking that observation and making a model with the Sun in the center produced a much cleaner series of nice circular orbits instead of labyrinthine explanations of retrograde motions, and it soon became the established teaching (despite some infamous early resistance from religious figures)