AS101 Chapter Notes - Chapter 2: Orbital Period, Flashlight, Northern Hemisphere
Document Summary
How the earth is moving: two basic motions, 1. Revolves around ( orbits ) the sun (very close to being a circle: 2. Stimulating the sky: do the stars rise and set like the sun, sort of, some rise and set, some don"t, are the stars up in the daytime, yes the daylight hides the stars. Learning goals: find our way around the night sky, measure angular size and the brightness of stars, how the earth revolution changes over the course of a year. Precession: a slow wobble: the earth is not perfect, has a bit of a bulge in the middle, the sun and moon are unevenly pulling on the slight (43 km) bulge around the. Earths equator: this causes a very slow but regular wobble of the earths axis, changes the ncp, this very slowly changes the position of the ncp, and all the other coordinates.
