Geocentric model they also appear to revolve around Earth about once per day. The stars appeared to be fixed on a celestial sphere rotating once each day about an axis through the geographic poles of Earth. Second, Earth seems to be unmoving from the perspective of an earthbound observer; it feels solid, stable, and stationary. Ancient Greek, ancient Roman, and medieval philosophers usually combined the geocentric model with a spherical Earth, in contrast to the older flat Earth model implied in some mythology. The ancient Jewish Babylonian uranography pictured a flat Earth with a dome-shaped, rigid canopy called the firmament placed over
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