Geocentric model the coordinate system in order to predict the motions of planetary bodies, though doing so may make calculations easier to perform or interpret. A geocentric coordinate system can be more convenient when dealing only with bodies mostly influenced by the gravity of the Earth (such as artificial satellites and the Moon), or when calculating what the sky will look like when viewed from Earth (as opposed to an imaginary observer looking down on the entire solar system, where a different coordinate system might be more convenient). The Ptolemaic model of the solar system held sway into the early modern age;
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