CAS AS 101 Lecture Notes - Lecture 18: The Moons, Continuous Spectrum, Thermal Radiation
Document Summary
Moon"s gravity pulls harder on near side of earth than on far side. Difference in moon"s gravitational pull stretches earth (tidal force), and raises tidal bulges. 2 high tides and 2 low tides each day. The sun also has a small tidal effect on earth (~ as strong as moon"s) The size of the tides thus depends on phase of the moon. Larger because the tidal forces of the sun and moon work together, leading to enhanced spring tides. Smaller because the tidal forces from the sun and the moon work against each other, leading to smaller neap tides. Tidal friction gradually slows earth"s rotation and makes the moon get farther from earth. Great example of conservation of angular momentum and energy. If earth didn"t rotate, tidal bulges would be oriented along the earth-moon line. Friction with the rotating earth pulls the tidal bulges slightly ahead of the earth-moon line.
