Geophysics to every area of the Earth sciences. To provide a clearer idea of what constitutes geophysics, this section describes phenomena that are studied in physics and how they relate to the Earth and its surroundings. The gravitational pull of the Moon and Sun give rise to two high tides and two low tides every lunar day, or every 24 hours and 50 minutes. Therefore, there is a gap of 12 hours and 25 minutes between every high tide and between every low tide. Gravitational forces make rocks press down on deeper rocks, increasing their density as the depth increases. Measurements
Chinese sun and moon mirrors "fangzhu" mirrors "jiàn" 見 "seeing" the sun and moon. The Way of Heaven is called the Round; the Way of Earth is called the Square. The square governs the obscure; the circular governs the bright. The bright emits "qi", and for this reason fire is the external brilliance of the sun. The obscure sucks in "qi", and for this reason water is the internal luminosity of the moon. Emitted "qi" endows; retained "qi" transforms. Thus yang endows and yin transforms. The unbalanced "qi" of Heaven and Earth, becoming perturbed, causes wind; the harmonious "qi" of Heaven and Earth, becoming calm,