|
|
|
For millennia, cultures have noted the lengthening of days as summer progresses, and celebrated the longest day of the year, after which the sun returns to the earth and the days become shorter. Stonehenge, the Big Horn Medicine Wheel, and other such structures attest to the importance of tracking the sun as it moves across the sky; sowing of seed, hunting of game, and other events were planned in accordance with the sun’s actions. Although we now know that the solstice itself is caused by the movement of Earth in an orbit that is tilted 23.5 degrees to the direction of the equator (this tilt results in constantly changing solar illumination at Earth’s different latitudes), the change of seasons is no less awe-inspiring.