Changes occur with sun strength and depend on what position the sun is relative to the globe. Ie seasonal changes (summer vs winter) or day vs night. There is oscilation of flux due to the fact that earth is rotating. Winters in the northern hemisphere are milder compared to winders in the southern hemisphere, but summers are colder in the north (warmer in the south) When the north hemisphere is rotated away from the sun, it is closer to the sun than the southern hemisphere is when it is rotates away. Sun spots: periods of time where the flux from the sun increases. Orbital cycles have little effect on the total amount of energy earth gets from the sun. Eccentricity: the shape of earths orbit as a degree to which it differs from a circular orbit. Low eccentricity = more circular, high eccentricity = more eliptical.