Sunsets, Stonehenge and solstices
December 20, 2019
By Emily Sandberg
Are you the opposite of a night-owl? Do you head to bed as soon as the sun begins to set? On December 21, we will have the longest night of the entire year. So, go ahead—press snooze! But, if you do keep your eyes open, you’ll get to see the constellations earlier than usual.
Are you the opposite of a night-owl? Do you head to bed as soon as the sun begins to set? On December 21, we will have the longest night of the entire year. So, go ahead—press snooze! But, if you do keep your eyes open, you’ll get to see the constellations earlier than usual.
On December 21 at 11:19 PM, we will celebrate the annual winter solstice. Every year, the solstice occurs in late December and marks the shortest day of the year. Here in Chapel Hill, we will only see around nine and a half hours of sunlight!
On December 21 at 11:19 PM, we will celebrate the annual winter solstice. Every year, the solstice occurs in late December and marks the shortest day of the year. Here in Chapel Hill, we will only see around nine and a half hours of sunlight!
What’s going on between the Earth and the Sun? Well, besides being a bummer if you enjoy late sunsets, the winter solstice features the sun at its lowest point in the sky. In specific science terms, this means that although the Earth’s axis is tilted at a constant angle, for people in the Northern Hemisphere the Sun will be at its lowest point resulting in the shortest day of the year.
But after this solstice the days will grow longer until the next one in June, the summer solstice, which will mark the longest day of the year. This phenomenon affects aspects of our daily life, such as the length of the days and even the length of our shadows! In fact, many ancient cultures used shadows and the sun’s position in the sky during the solstice to advance their study of astronomy.
Some cultures even developed folklore surrounding these topics. The most famous example of this is Stonehenge, built between 2400 and 2600 BC in Wiltshire, England. You may have heard about Stonehenge on a History Channel documentary with aliens and conspiracy theories, but did you know it is actually believed to have been built as a type of solar calendar?
Many historians believe that Stonehenge wasn’t just a pile of rocks— they suspect that it was used to track the movement of the sun. Specifically, the sun’s shadows.
Why did people in ancient England care about tracking the sun’s shadows? Well, they didn’t have iPhones to tell them what time it was or what season they were in or even when the winter solstice would occur. For them, the sun provided this vital information! Stonehenge’s alignment allowed them to pinpoint these movements and carefully chart how the shadows would land at a certain point in the day or year.
During the winter solstice, the sunset perfectly aligns with the structure. Thanks to this, the ancient people knew when to plant crops and have their midwinter feast. Pretty advanced for a heap of rocks, right?
Luckily, we don’t need Stonehenge to tell us what season it is anymore. Thanks to modern technology, we can confidently say that the solstice will be on December 21 this year, so be sure to prepare for this short day!
Interested in learning more?
Check out Morehead Planetarium & Science Center’s fulldome planetarium show “The Longest Night: A Winter’s Tale” to learn more about the sun’s journey throughout the year. “The Longest Night” is a show produced by Morehead in conjunction with Paperhand Puppet Intervention. In the show, you will follow the story of a girl’s treacherous journey through the longest night of the year. The story is also accompanied by a star tour explaining the science behind the winter solstice. This is a special show part of our winter schedule running now until February 23, 2020. We hope to see you there!