Seasons have had and still have a profound effect in human history, society, and psychology. The dramatic changes in the landscape that occur throughout the year have affected and are still affecting many facets of humanity from trade and warfare to the economy and the arts, and from moods to physiology. But far from the seasons being a mystery, human beings through observation and experiment have been able to determine that the cause of the seasons is the tilt in the Earth’s axis.
As the Earth orbits around the sun, it does so with a tilt of 23.5 degrees with respect to the plane of its orbit. As a result of this, the Earth’s poles point towards or away from the sun at the extremes of this orbit (solstices), while during the points of the orbit at right angles to the solstices neither one pole or the other point away from the sun (equinoxes). If the Earth’s axis did not have a tilt, there would be no seasons. Imagine how different human history, society, and psychology would be!
In the images below, Science Cat demonstrates Summer, Fall, Winter and Spring with the help of an Azalea bush that grows outside of our living room window.
Image from Wikipedia of the orbital relations of the Solstice, Equinox and intervening seasons by Colivine is used here under a CC0 1.0 Universal (CC0 1.0) Public Domain Dedication license.
The images of Science Cat belong to the author and can only be used with permission.