Traditionally the seasons were marked out as the planet runs through its yearly orbit around the sun. The seasons were on a continual cycle that reflects, the recognition of this psyco-energic shift. The axial tilt causes one half of the Earth and then the other to point more directly toward the sun. This is the reason that the day to night ratio is constantly changing from the longest day on the summer solstice (June 21st) to the shortest on the winter solstice - December 21st. It seems logical that dividing the year into two equal parts (four if we include the vernal and autumnal equinoxes) is the best means to account for seasonal phenomena and the affects associated with them.

The length of the day obviously influences the processes on our planet. However there is also another process which strongly influences the yearly cycle. It is the fact that the Earth’s orbit around the Sun is asymmetrical. This observation was first made in the fifteenth century by the astronomer Johannes Kepler (right) who stated in his first law that planets move in ellipses with the Sun at one focus. Circular orbits are a special case where both foci are in the same place. (Such perfectly circular orbits are almost non-existent in nature)