‘Tis the season… for astronomy and engineering! After all, the Winter Solstice occurs on December 21 and there’s more to celebrate than the start of longer days.
The Winter Solstice occurs every December and marks the shortest day of the year in the northern hemisphere. But, why does the length of the day change throughout the year? Thankfully, astronomy explains it all.
The Earth is tilted on its axis – 23.5 degrees to be exact. In the Northern Hemisphere, the Earth is tilted away from the sun during winter and toward the sun during summer. The Winter Solstice is just one of four major “way stations” on the Earth’s journey around the sun. The Summer Solstice marks the longest day of the year in the Northern Hemisphere and the Vernal and Autumnal Equinoxes mark the days when night and day are exactly the same length.
Most of us don’t celebrate the Winter Solstice and we don’t usually celebrate the holidays with math. However, engineering was a major part of Winter Solstice traditions in ancient times.
Thousands of years ago, monuments all over the world were designed and built to align with the sun on the day of the Winter Solstice. Some of these include Stonehenge in England, Newgrange in Ireland, and Chichen Itza in Mexico. Check out this video to learn how this works at Egypt’s Karnak Temple.
So how exactly did ancient societies construct these monuments? There are many theories, but experts agree that the monuments are impressive engineering feats. For example, one of the most famous sites, Stonehenge, includes 40-ton stones transported from more than 155 miles away. The builders may have used sleds and rollers or even large woven baskets to move the stones. Even the holes that hold the stones in place were dug at specific angles to ensure the stones did not fall. Stonehenge has been dated to 3000 BC to 2000 BC – even before the invention of the wheel – making its construction even more remarkable.
Be sure to celebrate this Solstice with science! Check out our “Cool Experiments” Pinterest board for some fun winter-themed activities.