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;
The Places in Between The Places in Between "The Places in Between" is a travel narrative by British writer and Member of Parliament Rory Stewart, detailing his solo walk across north-central Afghanistan in 2002. Stewart arrives in Afghanistan in January 2002, beginning his journey in Herat and proceeding on foot to Kabul. He is initially accompanied by two armed guards, Qasim and Abdul Haq, at the insistence of Governor Yuzufi but travels without human company for most of his walk, accompanied only by his dog, Babur. On his journey, Stewart encounters many of Afghanistan’s most notable historical sites, including the Minaret of Jam, the