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Article: Polar Axis and Tilt
- Article from:
- World of Earth Science
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Polar axis and tilt
The polar axis is an imaginary line that extends through the north and south geographic poles. Earth rotates on its axis as it revolves around the
Sun
. Earth's axis is tilted approximately 23.5 degrees to the plane of the ecliptic (the plane of planetary orbits about the Sun or the apparent path of the Sun across in imaginary celestial sphere). The tilt of the polar axis is principally responsible for variations in solar illumination (
insolation
) that result in the cyclic progressions of the
seasons
.
Earth rotates about the polar axis at approximately 15 angular degrees per hour and makes a complete
rotation
in 23.9 hours. The length of day has changed ...