Figure 6h-9: This animation displays the geometric relationship that occurs between the Earth and the Sun during the autumnal equinox and vernal equinox. The yellow line on the Earth represents the equator. The green lines are the Tropic of Cancer and Capricorn. The Arctic and Antarctic Circles are shown with red lines. In the animation, neither of the Earth's poles are tilted toward the Sun. This condition causes the Sun's rays to be most intense at the equator. This is illustrated on the animation by the location sideways yellow T. For any location on the equator, the Sun's position in the sky would be at 90° or directly overhead at solar noon. Finally, because the circle of illumination intersects the two poles all locations on the Earth have days that are 12 hours long.
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