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
Wall of the Sun and Wall of the Moon Wall of the Sun and Wall of the Moon The Wall of the Sun and Wall of the Moon are a pair of murals made of ceramics and designed by the Catalan artist Joan Miró for the UNESCO building in Paris. The works were carried out by the ceramicist Josep Llorens Artigas in 1955. Initially, the walls were installed on the Place de Fontenoy in Paris, but afterwards were enclosed in a building that was constructed in order to protect them from damage caused by acid rain. Joan Miró and Josep Llorens Artigas met in 1910 at the school of