Is there a relationship of the earths equinoxes and solstices and its orbit eccentricity?
I believe so… Currently Earth’s perihelion (point in orbit closest to sun) is near the southern solstice. Since Earth travels fastest in its orbit near the perihelion, that means the average speed of Earth’s orbit is higher in the period from the September equinox to the following March equinox than it is in the period from the March equinox to the following September one. As such, the total amount of time between the Sept equinox to the following March equinox will be slightly less than the precise amount of time between the March equinox and the next Sept equinox. As an example, this year’s March equinox was March 20, and the Sept one is Sept 22. That is a distance of 186 days. The next March equinox in 2010 is March 20 again, which is a distance of 179 days, somewhat less. This difference is due to the eccentricity of Earth’s orbit, and I’m sure you could use the difference in some way to calculate the eccentricity, but I am not going to figure how right now…
