Why does the Earth have seasons?

Why does the Earth have seasons?

Contrary to popular belief, the Earth's seasons are not caused by the varying distance from the sun. They occur because of the tilt of our planet's axis (23.5 degrees) in relation to the plane of the sun. As the Earth orbits the sun, our planet's tilt causes the intensity of sunlight to change over parts of the Earth at different times. The following describes the seasons in terms of the Northern Hemisphere:

Summer - When the geographic North Pole is tilted toward the sun, it is summer in the Northern Hemisphere. During this time, the North Pole receives 24 hours of daylight, while the South Pote experiences total darkness. On the Northern Hemisphere's first day of summer-or the summer solstice-the sun's direct rays are shining at 23.5 degrees north latitude, also known as the Tropic of Cancer. This occurs on June 21 or 22, a day that contains the most  daylight hours .

Fall or Autumn  - The first day of autumn in the Northern Hemisphere occurs on September 22 or 23 and is called the autumnal equinox. On this day, the sun's direct rays are directly overhead at the equator and the hours of day and night are equal. (The North Pole experiences "sunset" on this day, while the South Pole experiences "sunrise.")

Winter - December 21 or 22 is the first day of winter for the Northern Hemisphere and is called the winter solstice. During this time, the South Pole receives 24 hours of daylight, while the North Pole experiences total darkness. On the Northern Hemisphere's first day of winter, the sun's direct rays are directed at the Tropic of Capricorn, or 23.5 degrees south latitude. This day contains the shortest number of daylight hours in the Northern Hemisphere.

Spring - Similar to autumn, the Northern Hemisphere's spring-or vernal equinox-occurs when the sun's direct rays are once again at the equator. Spring occurs on March 21 or 22, and day and night are again of equal length. (The North Pole experiences "sunrise" on this day, while the South Pole experiences "sunset.").