ASTR 101 Lecture Notes - Lecture 6: Antarctic Circle, Equinox
Document Summary
It is hotter in the summer and colder in the winter because if earth"s tilt. Horizon angle of the sun at midday: how high the sun is in the day. Indirect illumination is when you could see the shadow of an object. Sun illuminates the hemisphere that is oriented toward the sun more directly, resulting in more concentrated heating: also illuminates more of that hemisphere, which results in longer heating. As viewed from ground, the sun is up longer and down shorter. Fraction of the hemisphere that is illuminated. All orbits around the sun are ellipses. We are closest to the sun in winter. Seasons are opposite in the opposite hemispheres. Sun is high in the midday summer sky, while it is low in the midday winter sky. In north pole in winter, the sun is never seen. Tropic of capricorn and cancer is where you have direct illumination during many times of the year.
