Heliocentrism was the initial breakthrough in the Scientific Revolution which came from Polish mathematician and astronomer Nicolaus Copernicus. His essential argument was that “at the middle of all things lies the sun” and that the earth, like the other planets, revolves around it. Thus, the reason why this theory was so radical from religious perspective was the fact that earth was no longer unique or at the obvious center of God’s attention. This challenged the previous understanding of the Catholic Church that the attention of the entire universe was centered on the earth and its human inhabitants, among whom God’s plan for salvation unfolded.
P.S. I hope this helped as I just read about this in ‘Ways of the World’ by Robert W. Strayer for AP World History :)