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
Mahazat as-Sayd Protected 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 gazelle and red-necked ostrich have been reintroduced in the reserve. The area was once also home to wolves and two more