Happy Winter Solstice!

Happy Winter Solstice!

Happy Winter Solstice everyone! We can now start enjoying longer days here in Asheville and the northern hemisphere. Our friends at the AB-Tech Institute for Climate Education provided this article to shed some light on the science behind the solstice. (Be sure to click on the second image below for a cool time-lapse video of the Earth.)

Bring On The Light!

Are you tired of the long hours of darkness? If so – rejoice as the powers of light are about to overcome… the dark side (insert “Darth Vader's Theme” music here)!

The December (winter) solstice occurs at 12:30 AM EST tomorrow morning marking the beginning of astronomical winter in the northern hemisphere, and the return of more hours of daylight.

Earth's Rotation
Credit: Timeanddate.com Note: Not to scale

For many of us, the winter solstice passes almost unnoticed thanks to modern conveniences like electricity and cars with headlights. But these are relatively new technologies that allow us to function through the long hours of darkness that occur this time of the year. Past generations were much more aware of the changing seasons because the lack of natural light had a significant impact on one's ability to be productive. As a result, the winter solstice was a time of great celebration.1

Beginning tomorrow, we will gain precious daylight each day as the Earth's northern hemisphere begins to pick up more sunlight on our yearly trek around the sun. These changes occur because our planet is tilted 23.5° in relation to the sun. And, at the winter solstice in the northern hemisphere, the Earth's axis is tilted at its largest angle away from the sun as shown in the illustration below.

Today and tomorrow (12/21 and 12/22) are the days with the shortest daylight hours of 2011 here in Western North Carolina. Each day having just under 9 hours and 45 minutes of daylight in Asheville. Compare that to the 14 hours and 34 minutes of daylight that Asheville sees at the summer solstice in June, and you can understand why our ancestors would celebrate the return of the sun in late December with festivals that would last for days, even weeks.

I encourage you to take time over the next couple of days to notice where the sunrise and sunset occurs on the horizon. This is as far south as the sun will appear to us - and the difference between where the sun rises and sets in December, and where it rises and sets well to the north in June, is truly amazing.

Click on the image below to get an interesting perspective on how the sun's light changes on the Earth through the year.  This movie was produced from a series of images from the European Organization for the Exploitation of Meteorological Satellites (EUMETSAT).2

Timelapse of the Earth rotating
Credit: NASA images and animation using data ©2010 EUMETSAT Note: Not to scale

Want to learn more? The Institute is offering five classes over the winter:

  • Mountain Weather and Climate
  • How the Weather Works: How We Observe and Predict It
  • History of Meteorology, Weather Lore and How the Weather has Affected Historical Events
  • Aviation Weather Safety
  • Weather Lore MythBusters

Their classes don't require a scientific background, just a curiosity about the world around you. Check out the classes offered in the A-B Tech Continuing Education Catalog here.

1. http://www.timeanddate.com/calendar/december-solstice-customs.html

2. http://earthobservatory.nasa.gov/IOTD/view.php?id=52248&src=eoa-iotd

Happy Holidays!

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