Geocentric model and planets were holes in invisible wheels surrounding Earth; through the holes, humans could see concealed fire. About the same time, Pythagoras thought that the Earth was a sphere (in accordance with observations of eclipses), but not at the center; they believed that it was in motion around an unseen fire. Later these views were combined, so most educated Greeks from the 4th century BC on thought that the Earth was a sphere at the center of the universe. In the 4th century BC, two influential Greek philosophers, Plato and his student Aristotle, wrote works based on the geocentric model.
Amherst Central Business District Amherst Central Business District The Amherst Central Business District is a historic district encompassing the heart of downtown Amherst, Massachusetts. Centered on the northern section of the long town common, the area has been the civic and commercial heart of the town since the 18th century. The district was listed on the National Register of Historic Places in 1991, and slightly enlarged in 2011. Amherst was originally part of Hadley, settled in 1661, and was itself known to have colonial settlements by 1728. It was incorporated in 1768. Its earliest focal point of settlement was in what is now its