Winter Solstice, what is it?
Why is it called ‘solstice’?
The world ‘solstice’ comes from the Latin solstitium meaning ‘Sun stands still’, because the apparent movement of the Sun’s path north or south stops before changing direction. At the winter solstice, the apparent position of the Sun reaches its most southerly point against the background stars.
The earliest people on Earth knew that the sun’s path across the sky, the length of daylight, and the location of the sunrise and sunset all shifted in a regular way throughout the year. They built monuments such as Stonehenge in England – or, for example, at Machu Picchu in Peru – to follow the sun’s yearly progress.
But we today see the solstice differently. We can picture it from the vantage point of space. Today, we know that the solstice is an astronomical event, caused by Earth’s tilt on its axis and its motion in orbit around the sun.
Ian Hennes in Medicine Hat, Alberta, Canada, created this solargraphy between a June solstice and a December solstice. It shows the path of the sun during that time period.
Where should I look to see signs of the solstice in nature?
For all of Earth’s creatures, nothing is so fundamental as the length of daylight. After all, the sun is the ultimate source of all light and warmth on Earth.
If you live in the Northern Hemisphere, you can notice the late dawns and early sunsets, and the low arc of the sun across the sky each day. You might notice how low the sun appears in the sky at local noon. And be sure to look at your noontime shadow. Around the time of the December solstice, it’s your longest noontime shadow of the year.
In the Southern Hemisphere, it’s opposite. Dawn comes early, and dusk comes late. The sun is high. It’s your shortest noontime shadow of the year.
Day and night sides of Earth at the instant of the December 2019 solstice. Image via EarthView.
Top image: Lulworth Cove © Chris Kotsiopoulos