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Some Basics Notions about the Motion of the Earth

• Q. Why is there Day and Night? The Earth rotates on its axis once every 24 hours.
  

• Q. Why are there Seasons? The Earth's spin axis is tilted with respect to its orbital plane around the Sun.
  

The tilting of the Earth's spin axis with respect to the plane defined by its orbit around the Sun also leads to:

• The Sun takes a different path through the sky through the year.
  

• Winter daylight hours are fewer and the intensity of sunlight is less.

• Those last points are the reasons why it is colder in the winter. In the Northern hemisphere we are actually a little closer to the sun in the Winter.

• Seasons are reversed in the Northern and Southern Hemispheres.

• You see different stars at different times of the year.