The Story of the Seasons

2017-10-14 11:59:36.000 – Taylor Regan, Weather Observer

 

It’s been a fall-like summer and a summer-like fall this year, with the trees all out of sorts and calendars themselves questioning what month it really is. But how did the seasons become as delineated at they are? In Greek Mythology, the story of the seasons originates with Demeter, the Greek goddess of harvest.

According to the myth, Demeter, the goddess responsible for ensuring the harvest, had a young and joyful daughter named Persephone. Unfortunately, Persephone drew the attention of Hades, ruler of the underworld. Zeus granted Hades permission to marry Persephone, and so, whilst out picking flowers, Persephone was whisked away in Hades’ golden chariot, and taken to the land of the dead.

Demeter, wrought with grief over the disappearance of her daughter, cast aside her duties as goddess of the harvest, and searched the world for her beloved Persephone. Crops withered, fields dried up, and the world was at risk of famine as Demeter mourned the loss of her daughter. The drought was so severe that even traditional offerings to the gods were being neglected, because there simply wasn’t enough food. Zeus attempted to lift Demeter’s spirits by promising her all manner of gifts and powers, but nothing could assuage her anguish.

Seeing that he must act, Zeus sent Hermes to the land of the dead to retrieve Persephone, who, in her own grief, had neither eaten nor drank anything whilst being held in the underworld. While Hades knew he must follow Zeus’ orders, he still managed to trick Persephone into eating a few pomegranate seeds prior to returning home. While Demeter was overjoyed at the return of her daughter, she grew dismayed when she found out that Persephone had eaten while under Hades’ rule. The Fates had proclaimed that anyone who eats anything in the land of the dead must remain there. However, because she had eaten only seven seeds, she was destined to spend only seven months of the year in the underworld, and the other five she could return to Demeter.

The myth continues that, for the months that Persephone is with Hades, Demeter rules lonely and sad over the harvest. As Demeter morns, trees lose their leaves, cold returns, and fields lie fallow. However, when Persephone returns, Demeter rejoices, plants spring up from the ground, flowers sprout, and life returns. And that is the story of how the seasons were brought about.

Figure 1. Diagram showing the tilt of Earth vs. sunlight. (Image from Wikipedia)

In actuality though, the seasons are caused by the tilt of the Earth, which is roughly 23.5 degrees, relative to the surface formed by the Earth tracking a path around the Sun. In the winter, when the Northern Hemisphere is tilted away from the sun, cold air builds up over North America, Europe, and Asia. The light that does reach the Northern Hemisphere is spread over a greater surface, and therefore less warming is felt.

The Northern and Southern Hemispheres always experience opposite seasons, this is because as one pole tips towards the sun, the other is tipped away, and that hemisphere receives less incoming sunlight. Between the seasonal switches, there are two instances when the Sun is directly overhead at the equator. These are known as the equinoxes, and denote the time when day and night is equally divided between the hemispheres. The March Equinox marks the beginning of Spring in the Northern Hemisphere, and Fall in the Southern Hemisphere, whereas the Autumnal Equinox marks the beginning of Fall in the Northern Hemisphere, and Spring in the Southern Hemisphere.

Figure 2. Diagram depicting sunlight vs. the season. (Image from Wikipedia)

While other features such as storm tracks and proximity to water account for some seasonal variation, the largest factor governing the differences we experience between the seasons is due to the axial tilt of the Earth. It certainly isn’t as colorful a story as the Greek myth, but pretty interesting nonetheless!

 

Taylor Regan, Weather Observer