Longitude of perihelion

Figure 1 Sketch of the Earth s orbit around the Sun today and at the end of the last glacial cycle (11 000 years ago), showing the positions of fhe soisfices and equinoxes relafive fo perihelion. The longitude of perihelion (to) is measured as the angle between the line to the Earth from the Sun at spring equinox and the line to the Earth at perihelion.

The third and last variable affecting insolation is the longitude of perihelion (m). This parameter is... 

If the Earth s orbit were a circle, the distance to the Sun would remain constant at all times of the year and it would not make any difference where on the orbit the seasons were positioned. Therefore, the impact of variations in the longitude of perihelion depends on the eccentricity of the Earth s orbit and is described by... 

The motion is therefore doubly degenerate, since for a given value of J the energy is independent of Ja (the total angular momentum) as well as of J. Not only the longitude of the node, but also the angular distance of the perihelion from the line of nodes, remains unaltered. We have only one quantum condition,... 

An astronomical theory formulated by the Yugoslav mathematician Milutin Milankoviteh that associates climate change with fluctuations in the seasonal and geographic distribution of insolation determined by periodic variations of the Earth s eccentricity and obliquity and the longitude of the perihelion. 

---