ASTR 103 Lecture Notes - Lecture 2: Tidal Locking, The Moons, Aswan
Document Summary
The phases of the moon are caused by its orbital motion. As the relative positions of the earth, the moon and the sun change, we see more or. With respect to the stars, the moon completes one orbit around the earth in a sidereal month, averaging 27. 32 days. Sun) in a synodic month, averaging 29. 53 days. The moon"s rotation always keeps the same face toward the earth due to synchronous rotation. Eclipses occur only when the sun and moon are both on the line of nodes. Solar eclipses can be either total, partial or annular, depending on the alignment of the. Ancient astronomers measured the size of the earth and attempted to determine. Observations distances to the sun and moon. ~in alexandria, the position of the sun changed by 7 degrees or about 1/15 of a complete circle. Alexandria and syene to get a circumference of the earth about 42000 km (the actual size is about 40000 km)
