What key observation directly challenged the long-held geocentric doctrine?

Answer

The moons performed clear, independent orbits around Jupiter

The ability to see these four lights visibly circling Jupiter night after night demonstrated that centers of motion other than Earth existed in the celestial sphere, dismantling the core tenet of the geocentric universe.

What key observation directly challenged the long-held geocentric doctrine?
discoveryGalileoastronomyJupiterMoon