Orbits, Seasons, and Ice Ages

Notice that halfway in orbit, and on the calendar, the equinoxes take place. The Vernal, or Spring, Equinox is on March 20 or 21. The Autumnal, or Fall, Equinox is on September 22 or 23. The shape of the Earth’s orbit and the angle of tilt have changed over the 4.6 billion year history of the Earth. ................
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