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
First term of Fernando Chui as Chief Executive of Macau First term of Fernando Chui as Chief Executive of Macau The First term of Fernando Chui Sai On as Chief Executive of Macau, officially considered part of "The 3rd term Chief Executive of Macau", relates to the period of governance of Macau since the transfer of sovereignty of Macau, between 20 December 2009 and 20 December 2014. Fernando Chui Sai On was elected in mid 2009 by 300-member Selection Committee as the second Chief Executive of Macau. The policy bureaux were under several reorganisations during the term as following: The Executive Council was presided by President Fernando Chui Sai On