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 "Moon". The two mosaic murals were assembled "in situ" by a team of technicians under the direct supervision of Miró and Llorens Artigas. The works were inaugurated in 1958, as same as the building, and received rave reviews. Even one of the murals, the "Wall of the Sun" won the Biennial Prize of Guggenheim Foundation. Miró later return to work for UNESCO, designing the UNESCO Medal for Pablo Picasso. Initially, the walls were outdoors, but later moved inside the building to protect them from damage caused by acid rain. Wall of the Sun and Wall of the Moon The Wall