Geocentric model coelestium" ("On the Revolutions of the Heavenly Spheres"), which posited that the Earth and the other planets instead revolved around the Sun. The geocentric system was still held for many years afterwards, as at the time the Copernican system did not offer better predictions than the geocentric system, and it posed problems for both natural philosophy and scripture. The Copernican system was no more accurate than Ptolemy's system, because it still used circular orbits. This was not altered until Johannes Kepler postulated that they were elliptical (Kepler's first law of planetary motion). With the invention of the telescope in 1609,
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