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
Aisle (political term) Aisle (political term) In the United States, the two major political parties, the Republicans and the Democrats, are often referred to as "the two sides of the aisle." Usage of the term "aisle" comes from the United States Congress. In the Senate, desks are arranged in the chamber in a semicircular pattern and the desks are divided by a wide central aisle. By tradition, Democrats sit on the right of the center aisle (as viewed from the presiding officer's chair) while Republicans sit on the left. Unlike in the Senate, there are no assigned desks in the House of Representatives