One of the great controversies was the heliocentric versus geocentric theories that were competing at the time. The idea that the Earth was not the center of the known universe was dismaying to the Roman Catholic Church at the time, which saw the Earth as a special part of Creation that had to be at the center of everything. With Kepler and Copernicus espousing theories that put the Sun at the center of the local solar system instead of the Universe, it put them at odds with the religious people in power at the time, and caused much strife to the scientists.
