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Mark Fisher
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Equinox
Most of the time, the direction of the Earth's rotation around its own axis, and the direction of its orbit around the Sun, vary from one another. However, as the Earth tilts backward and forward in its orbit, relative to the Sun, these two angles coincide from time to time. This event is known as an Equinox, and happens twice a year, in March (the Vernal Equinox) and again in September (the Autumnal Equinox).

Diagram of the Equinoxes
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  • Autumnal Equinox
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