Sunday, Dec. 21, 2008
As you drove home from work on Friday, it was late autumn in the northern hemisphere.
And for folks in the southern hemisphere, it was late spring as the weekend began. Yet, when you return to work tomorrow, the season will have changed. It’ll be winter in the northern hemisphere, and summer in the southern hemisphere.
That’s because today is the December solstice. There’s nothing official about beginning and ending the winter or summer season at the solstice. But people around the world will mark this event, and its effect is felt everywhere worldwide. The December solstice – sometimes called the southern solstice – marks the instant the sun reaches its southernmost point in our sky for the year.
If you look at a schoolroom globe, you’ll see the Tropic of Capricorn some 23.5 degrees south of the equator. This is where the sun is at zenith – or straight overhead – at noontime today. If you look 23.5 degrees south of the North Pole, you’ll see the Arctic Circle. Every place north of the Arctic Circle sees no sun at all today. And every place south of the Antarctic Circle sees the sun all day long.
Meanwhile, for the rest of us elsewhere on the globe, today brings the southernmost sunrise and the southernmost sunset of the year. North of the equator, it’s the shortest day and the longest night of the year. South of the equator, it’s the year’s longest day.
The Dec. 21, 2008 solstice comes at 12:04 p.m. Universal Time. For more information on this and many other science topics, visit www.EarthSky.org.