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
Sun and Moon (Middle-earth) name given to the Sun by the Noldor. A poetic name for the Sun was the Daystar, and Gollum referred to it as the Yellow Face. The Sun was seen by the Elves as made on behalf of Men, and they valued the Moon more highly. Morgoth's creatures, the Orcs, feared the Sun, and with the exception of the Uruk-hai, they did not travel while it was in the sky. The Trolls of Middle-earth feared the Sun even more, and with great reason: they turned to stone under its light. Only the later Olog-hai were able to move under the