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Seasons
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Solstices:
mark the longest and
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shortest days of the years (June
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21 and December 21 in the
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northern hemisphere, the reverse
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in the southern)
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Equinoxes:
the length of night
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and day become equal in each
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hemisphere.
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At the present-day orbit, the
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winter and summer solstices
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differ from the aphelion and
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perihelion by about 13 days.
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