astronomy - What made us think that Earth moves around the Sun?

Trying to observe the night sky for a few weeks, the motion of the Sun and the stars pretty much fits into the Geocentric Theory i.e. All of them move around the Earth.

What then, which particular observation, made us think that it could be the other way around, that all the planets move around the Sun?

Answer

which particular observation, made us think that it could be the other way around

Retrograde motion must be a prime candidate.

^{As seen from Earth against star background, Mars occasionally slows down and goes backwards. Our moon doesn't.}

It probably became clear to people constructing orreries that heliocentric models were enormously simpler and more convincing. They also tied in with simple inverse square laws of gravitation and planetary motion.

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The discovery by Galileo Galilei of Jupiter's moons also provided firm evidence of the existence of heavenly objects that, perversely, did not orbit the Earth.

^{Photo: Thomas Bresson (Galileo probably didn't have a Nikon / mobile phone handy)}

^{Luckily, he had available a corner of a napkin, a goose and some soot (or equivalents)}