Wednesday, December 28, 2011

Welcoming the Sun: the changing of the seasons

Imagine a time before electricity when the waking hours were determined by the length of the day. Darkness would fall and it would be difficult to conduct much business or continue work without the aid of a strong fire. As the day closes with a shorter period of light, it is common for people to spend more time inside; plants and animals begin to conserve energy, hibernate or migrate. The winter solstice heralds in the sun as each day becomes slightly longer in light. This was a time of celebration marked with lighting candles and fires so as to welcome the sun and the growing period for many ancient cultures. Consider some of your own holiday and religious traditions where lights, candles,or fires are lit to celebrate.
The Earth as it rotates around the sun is on a tilt. This tilt is slight, but makes all the difference. Gail Gibbons in her book The Reasons for the Seasons outlines this very nicely. Although focused towards a youthful audience it gives a clear and well illustrated depiction of the seasonal changes that occur. “As the Earth circles the sun, different parts of the Earth are closer to the sun than others. This affects the amount of light and heat they receive,” Gibbons explains. Currently, the North Pole is pointed away from the sun causing us in Billings, Montana to experience winter. Transversely, Montana experiences summer when the North Pole is tilted towards the sun.

The seasons are divided by the position of the globe and its tilt in relation to the sun.
December 21: the winter solstice is a day with the longest period of darkness.
March 21: the vernal equinox is a day of equal lengths of day and night
September 21: the autumnal equinox is a day of equal lengths of day and night
June 21: the summer solstice is a day with the longest period of light
Our spring and fall equinox, as the name would suggest, is when the sun is hitting most directly at the equator. The summer and winter solstice occur when the sun is most directly over the Tropic of Cancer and the Tropic of Capricorn, respectively.

Slowly each day will peel back with a little more light as the winter solstice just passed a week ago today. The winter solstice is a time to welcome the light and the lengthening of days. If you would like to be more aware of these seasonal changes consider: noting in the local newspaper the times of the sunrise and sunset; taking a walk outside and observing any changes in the temperature, the budding of plants, the movement of animals; or even attempting to do a particular activity at the same time each day and gauge how much light you have. These activities will make the subtle change in light become more apparent as we approach the vernal equinox.

Mattie Clark
Big Sky Watershed Corps and AmeriCorps member

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