Nicholas Copernicus' work was devoted to proving his heliocentric theory. Using mathmatics, he was able to conceive the theory of earth being the third planet from the sun,and began developing the concept of gravity, saying "Large masses have theit own attraction forces". 

 

      Galileo Galilei was dedicated beyond prison, and house arrest. Perfecting the telescope, he could see beyond the stars, seeing craters on the moon (proving heaven isn't perfect) and was later brought into a sticky situation with the Spanish Inquisition, after writing Starry Messenger in 1610.

In 1633, Galileo was forced to recant, after openly supporting Copernicus, adn was placed under house arrest. He later developed the theory of Inertia.

 

     Isaac Netwon took ideas from both of these two previous astronomers, publishing his Principia using Copernicus' idea of gravity, and Galileo's idea Inertia. Newton also published "his" three laws of motion. All of these ideas relate to a heliocentric universe some way or another.