Answer:
Diffusion is a process whereby something spreads more widely. In cultural terms, this means that as an influential trend begins in one area, people in other areas pick up on it and try to imitate or adapt it.
It was important because it proposed a completely different view of the universe and the position of the Earth and Sun within it. Prior to Copernicus, it was thought that the Earth was stationary and that everything in our galaxy revolved around it. However, the heliocentric model proposed a different view - it means that the Sun is actually the center of the galaxy, and everything within the Milky Way, including the Earth, revolves around that star.
It may have caused the spread of disease and economic problems.