Geocentric model explanation in terms of the Earth's revolution about the sun. In 1838, astronomer Friedrich Wilhelm Bessel measured the parallax of the star 61 Cygni successfully, and disproved Ptolemy's claim that parallax motion did not exist. This finally confirmed the assumptions made by Copernicus, providing accurate, dependable scientific observations, and conclusively displaying how distant stars are from Earth. A geocentric frame is useful for many everyday activities and most laboratory experiments, but is a less appropriate choice for solar system mechanics and space travel. While a heliocentric frame is most useful in those cases, galactic and extragalactic astronomy is easier if
Central bank In this context, independence is usually defined as the central bank's operational and management independence from the government. Central bank independence is usually guaranteed by legislation and the institutional framework governing the bank's relationship with elected officials, particularly the minister of finance. Central bank legislation will enshrine specific procedures for selecting and appointing the head of the central bank. Often the minister of finance will appoint the governor in consultation with the central bank's board and its incumbent governor. In addition, the legislation will specify banks governor's term of appointment. The most independent central banks enjoy a fixed non-renewable term