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
Long Term Ecological Research Network Long Term Ecological Research Network The Long Term Ecological Research Network (LTER) consists of a group of over 1800 scientists and students studying ecological processes over extended temporal and spatial scales. Twenty-six LTER sites cover a diverse set of ecosystems. It is part of the International Long Term Ecological Research Network (ILTER). There are 28 sites within the LTER Network across the United States, Puerto Rico, and Antarctica, each conducting research on different ecosystems. LTER sites are both physical places and communities of researchers. Some of the physical places are remote or protected from development, others are deliberately located in