Geocentric model much farther away than the Sun and the planets than previously conceived, making their motion undetectable, or in reality they are not moving at all. Because the stars were actually much further away than Greek astronomers postulated (making movement extremely subtle), stellar parallax was not detected until the 19th century. Therefore, the Greeks chose the simpler of the two explanations. Another observation used in favor of the geocentric model at the time was the apparent consistency of Venus' luminosity, which implies that it is usually about the same distance from Earth, which in turn is more consistent with geocentrism than
Umbrella term term, by itself, gives little detail about the things that it describes or the relationships between them, but it is easy to say and remember. Blanket terms may originate as slang but eventually become integrated into the general vocabulary. Umbrella term An umbrella term is a popular metaphorical phrase that covers a wide range of concepts belonging to a common category. For example, "cryptology" is an umbrella term that encompasses cryptography and cryptanalysis, among other fields. Similarly, an umbrella organization is a central and coordinating body representing a number of smaller, separate bodies. A blanket term is a closely related