Moon clouds. The illuminated area of the visible sphere (degree of illumination) is given by formula_3, where formula_4 is the elongation (i.e., the angle between Moon, the observer (on Earth) and the Sun). The gravitational attraction that masses have for one another decreases inversely with the square of the distance of those masses from each other. As a result, the slightly greater attraction that the Moon has for the side of Earth closest to the Moon, as compared to the part of the Earth opposite the Moon, results in tidal forces. Tidal forces affect both the Earth's crust and oceans. The
Geostationary ring Geostationary ring The geostationary ring is a volume segment around the geostationary orbit defined by variations in altitude and declination that can occur for uncontrolled objects left in the geostationary orbit. The geostationary orbit is subject to orbit perturbations caused by anomalies in the gravitational field of the Earth, by the gravitational effects of Sun and Moon, and by solar radiation pressure. A precessional motion of the orbit plane is caused by the oblatedness of the Earth (formula_1), and the gravitational effects of Sun and Moon. This motion has a period of about 53 years. The two parameters describing the