If the sun appears to set a little earlier (or later) this Sunday, it is not your imagination. That's because depending on where you live, December 21st will be the shortest or longest day of 2014. Also known as the winter (or summer) solstice, it marks the official start of winter for the residents of the Northern Hemisphere and summer for those that live in the Southern Hemisphere.
The reason behind the disparate seasons is of course all to do with the way earth rotates around the sun and its own axis, which is tilted at a 23.5° angle. This results in the Northern Hemisphere receiving a lot less sunlight than the Southern Hemisphere during this time of the year. The solstices occur when the sun is at the greatest distance from Equator, the imaginary line that divides earth into the two hemispheres. The date the solstices occur vary from December 20th - 23rd because the modern calendar of 365 days a year, with an extra day every four years, does not correspond exactly to the solar year of 365.2422 days.
While we now know why they occur, for ancient cultures the winter solstice was extremely important because after this day, the sun appeared to magically return and remain in the skies for an increasingly longer time each day. Though many months of winter still remained, they were comfortable in the knowledge that the energy giving star had not abandoned them.
To celebrate the occasion, many ancient cultures held elaborate ceremonies and even constructed some amazing structures. One of the most famous examples is Stonehenge in Wiltshire, England. Hundreds of people still gather here each year, to celebrate a pagan tradition called Yule, one of the oldest known solstice-related events.
Also famous for its winter solstice celebrations is Newgrange in Boyne Valley, Ireland. The 5,000 year-old giant stone structure that historians estimate took 300 men about 20 years to build, is designed to receive a ray of light into its central chamber at the dawn of winter solstice. The light in turn illuminates incredibly intricate carvings. The illumination that takes a total of 17 minutes from start to finish, is so popular, that viewing tickets are now distributed through lottery.
Many cities in the USA have also started their own winter solstice traditions. In Northern California, the Muir Woods National Monument will host a special celebration for families from Noon to 5 p.m. Visitors can weave a solstice crown, enjoy seasonal songs and help light ceremonial lanterns in anticipation of the longest night of the year. The residents of Anchorage, Alaska, plan to spend part of the 18 hour 33 minute night with fun activities like sleigh riding and watching spectacular fireworks. Does your town or city have a special solstice celebration? Be sure to share it with us by adding your comments below.
Resources: earthsky.org, wikipedia.org