Geocentric model knew about Tusi's work or that of the Maragha school. Not all Greeks agreed with the geocentric model. The Pythagorean system has already been mentioned; some Pythagoreans believed the Earth to be one of several planets going around a central fire. Hicetas and Ecphantus, two Pythagoreans of the 5th century BC, and Heraclides Ponticus in the 4th century BC, believed that the Earth rotated on its axis but remained at the center of the universe. Such a system still qualifies as geocentric. It was revived in the Middle Ages by Jean Buridan. Heraclides Ponticus was once thought to have proposed
Central Illinois Regional Airport for the Central Illinois Air Derby. Billed at the time as the greatest such event in Illinois outside of Chicago, the show included four U.S. Army "ships" from Chanute Field in Rantoul, civilian aviators from places like Aurora, Champaign, Joliet and Kankakee, aerial "stunting" contests and races, parachutists and an air parade over downtown Bloomington. Despite the efforts of local aviation enthusiasts and the business community, attempts to establish long-term passenger service at the Normal field ended in failure. In the fall of 1931, Century Air Lines added Bloomington to its Chicago-to-St. Louis route, and the little grassy square (recently