The days are getting longer!
Think back for a moment to the winter solstice on December 21. Sunrise and sunset in Bismarck were at 8:25am and 4:47pm respectively, that is only 8 hours and 32 minutes between sunrise and sunset. On Friday, March 20, at 9:46 a.m., the sun crossed the celestial equator — marking the spring equinox. As the term “equinox” indicates, there is roughly equal time between sunrise and sunset around the globe.
On Friday, March 20, sunrise and sunset in Bismarck were at 7:45 a.m. and 7:55 p.m., respectively. That is 12 hours and 10 minutes between sunrise and sunset, or an increase of 3 hours and 38 minutes more than on the winter solstice!
And as most everyone knows, the days will continue to lengthen until the summer solstice, which comes this year on June 21, when sunrise and sunset in Bismarck will be 5:48 a.m. and 9:41 p.m. — a whopping 15 hours and 52 minutes between sunrise and sunset. But after that, the days begin to shorten through the fall equinox in September and the winter solstice in December.
Seasonal changes are due to changes in the directness of the sun’s rays on the earth. If the earth’s rotation was perpendicular to the plane of its orbit, we wouldn’t have much if any variation in seasons. But the earth is tilted on its axis by 23 1/2 degrees. As a result, variations in the directness of the sunlight hitting the earth’s surface changes throughout the year, giving us the seasonality here in temperate zones. While we in the northern hemisphere celebrate the first day of spring, people in the southern hemisphere are marking the first day of fall, and probably not as excited about it.
Stonehenge in Great Britain, Newgrange in Ireland, Carnac in France, and Chichen Itza in Mexico are some of the more well-known structures built to mark these events. There is also a modern-day medicine wheel in Valley City, and Turtle Mountain has Mystical Horizons, a “modern day Stonehenge.” You can learn more about that here.
Happy Spring!
