Geocentric model work, the "Almagest", was the culmination of centuries of work by Hellenic, Hellenistic and Babylonian astronomers. For over a millennium European and Islamic astronomers assumed it was the correct cosmological model. Because of its influence, people sometimes wrongly think the Ptolemaic system is identical with the geocentric model. Ptolemy argued that the Earth was a sphere in the center of the universe, from the simple observation that half the stars were above the horizon and half were below the horizon at any time (stars on rotating stellar sphere), and the assumption that the stars were all at some modest distance
Term (time) the four-year presidential term, there are also academic midterm exams. In economics, it is the period required for economic agents to reallocate resources, and generally reestablish equilibrium. The actual length of this period, usually numbered in years or decades, varies widely depending on circumstantial context. During the long term, all factors are variable. In finance or financial operations of borrowing and investing, what is considered "long-term" is usually above 3 years, with "medium-term" usually between 1 and 3 years and "short-term" usually under 1 year. It is also used in some countries to indicate a fixed term investment such as