AST 101 Lecture Notes - Lecture 24: Semi-Major And Semi-Minor Axes, Galilean Moons, Celestial Sphere

• School: Syracuse University
• Department: Astronomy
• Course: AST 101
• Professor: Walter Freeman

Document Summary

The earth"s axis is not lined up with its orbital axis. Axis of rotation changes only very slowly axis is off on zodiac. Noon each day, the sun will rise high and low in the sky, not east and west relative to the stars. Solar day suns east west position stays fixed but stars move east. Sidereal day stars position stays fixed but sun moves west. Solstice- time of year when earths axis is tilted toward the sun the most. Equinox periods where the earths tilt is sideways to the sun. Tropics region on earth where the sun alternates between the northern sky and the southern sky. Tropic of cancer northern boundary: june solstice, zenith hits this. Tropic of capricorn southern boundary: december solstice, zenith hits this. Arctic (north) antarctic (south) region where sun never rises or sets during certain parts of the year. Nothing to do with distance from the sun.