by Cicely Richard

Created on: June 03, 2008

Both solstice and equinox refer to the seasons in a calendar year. These seasons come about because of the Earth's position in relation to the Sun; therefore, solstice and equinox happen four times a year. Solstices occur during winter and summer around December 21 and June 21 while equinox occurs during spring and fall around March 21 and September 22. The terms refer to the Earth's axis in relation to the Sun. There are a few notable differences between solstice and equinox.

Solstice occurs when the point of the Earth's axis is pointed directly toward or away from the Sun. When this happens, the Sun appears have reached it southernmost or northernmost points, or poles. During the summer solstice, usually the first day of summer, the Sun is farthest north and the time between sunrise and sunset is the longest. Summer solstice is said to be the longest day of the year. On this day, many individuals take advantage of the extra sunlight to do more outdoor activities than any other day of the year. On the other hand, winter solstice, usually the first day of winter, the Sun is farthest south and the length of time between sunrise and sunset is shorter, leaving fewer hours of sunlight on this particular day.

Unlike summer and winter solstice, equinox is when both day and night are the same length. This takes place because the Sun is crossing the equator and is an equal distance from the North Pole and the South Pole. However, the Poles do not experience the equilibrium of day and night during this time of year. Spring equinox, often the first day of spring, is the beginning of an extended period of sunlight at the Pole. At this time, the days gradually lengthen as the season progresses. Fall equinox, on the other hand, signals the beginning of long periods of darkness at the Pole. These extended periods take place because, at the Poles, the Earth's atmosphere bends Sun rays enough to make the Sun visible both day and night, for the duration of the 12-hour period when the Sun is below the horizon.

The solstice and the equinox is more than times of the year for individuals throughout history. The position of the Sun has been used to signify religious rites and an instrument in creating early time pieces. In particular, almost all devout groups in Christianity, Judaism, and Paganism rely on the sun for many of their festivals and ceremonies. While most people don't think of the change of season in this way, almost everyone plans their annual activities by the position of the Sun, whether they realize it or not. So, next time you debate over what to wear on any given day, remember your decision is based on the difference between solstice and equinox.

Sources:

http://www.athropolis.com/sunrise/de f-sol2.htm
www-istp.gsfc.nasa.gov/stargaze/Sseason.ht m
http://encarta.msn.com/encyclopedia_761587790/seaso n.html

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