AST 101 Lecture Notes - Lecture 5: Antarctic Circle, Northern Hemisphere

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

Document Summary

We can only see light in the visible spectrum, but there are many more kinds of light we cannot see . The earth"s axis of rotation is not lined up with its orbital axis. The axis of rotation changes only very slowly over millennia (thousands of years) We give special names to the points in earth"s orbit where the earth"s axis is tilted directly toward/away from the sun: Summer solstice: northern axis is closest to the sun, occurs on about. Winter solstice: northern axis is furthest from the sun, occurs on about. Spring/vernal equinox: northern axis and southern axis are equidistant from the sun, occurs on about march 21. Fall/autumnal equinox: northern axis and southern axis are equidistant from the sun, occurs on about september 21. The region on earth where the sun alternates between the northern sky and the southern sky is called the tropics. The northern boundary is called the tropic of cancer.