Geocentric model Geocentric model In astronomy, the geocentric model (also known as geocentrism, or the Ptolemaic system) is a superseded description of the Universe with Earth at the center. Under the geocentric model, the Sun, Moon, stars, and planets all orbited Earth. The geocentric model served as the predominant description of the cosmos in many ancient civilizations, such as those of Aristotle and Ptolemy. Two observations supported the idea that Earth was the center of the Universe. First, from anywhere on Earth, the Sun appears to revolve around Earth once per day. While the Moon and the planets have their own motions,
Mahazat as-Sayd Protected Area species of gazelles, the idmi and dorcas gazelle. It is likely that striped hyenas and cheetahs once also inhabited the area. Mahazat as-Sayd Protected Area The Mahazat as-Sayd Protected Area is a 220,000 ha large protected area in central Saudi Arabia. The area is totally fenced and protection from livestock grazing has allowed a spectacular recovery of native vegetation. The reserve is now dominated by grasslands, which are a reminder of what most of the Arabian peninsula may have looked once. Mahazat as-Sayd is one of the few places where the Arabian oryx has been reintroduced. In addition the reem