What specific observation by Galileo most devastatingly challenged the idea that everything in the heavens orbited the Earth?

Answer

Discovering four small bodies orbiting Jupiter

Galileo's discovery of the Galilean moons demonstrated unequivocally that multiple centers of motion existed in the heavens, thereby proving that not everything orbited the Earth.

What specific observation by Galileo most devastatingly challenged the idea that everything in the heavens orbited the Earth?
Galileoastronomyscientistuniverseheliocentrism