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Part 5.  The axis of the Earth.

Mid-winter in the northern hemisphere is when the Earth’s axis is tilted away from the Sun. The Sun never rises at the North Pole between October and March while at the South Pole the Sun never sets.
		Mid-summer in the northern hemisphere is when the Earth’s axis is tilted towards the Sun. The Sun never sets at the North Pole between April and September while at the South Pole, the Sun never rises.

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