In 2021, the winter solstice for the Northern Hemisphere occurs December 21. Although not as dramatic as the 2020s conjunction of Jupiter and Saturn, the longest night of the year is a significant turning point. Astronomical winter begins and the days gradually lengthen again.
I wonder why this is happening? WIRED spoke with Tansu Daylan, a Transit satellite for exoplanets (TESS) is a postdoctoral fellow at MIT to better understand the winter solstice and our planet’s relationship to the sun.
To imagine what happens in space during the winter solstice, start by thinking about a giant glass ball surrounding the Earth, and let’s ignore the rotation of the planet (which complicates everything). Daylan says, “If you look at the three-dimensional sphere around us known as the celestial sphere, the sun and all other objects in the solar system move across a plane in this celestial sphere known as the ecliptic plane.
“As he does this, the sun changes its inclination,” he says. Declension and proper ascent are the two main axes of the celestial sphere. “In this frame of reference, the sun is at its southernmost point, when the winter solstice is from our point of view in the Northern Hemisphere.”
The winter solstice in the Northern Hemisphere occurs when North Pole is inclined farthest from the sun. The Arctic Circle is shrouded in darkness and is experiencing its longest night of the year. In the southern hemisphere, the summer solstice occurs simultaneously with the South Pole, facing the Sun and the Antarctic Circle, midnight sun.
NASA’s online tutorial “Fundamentals of Space Flight” includes a section on celestial sphere with illustrations for anyone who would be happy to explore the idea further.
The low position of the sun during the winter solstice will cause you lunch shadow to be extremely long. Although important to humans, the solstice does not matter much to the larger cosmos.
“Solstices are determined by the Earth-Sun system, not necessarily the entire solar system. “We attach a lot of importance to this because the sun is so sacred to us, and its location in the celestial sphere, as a function of year-round weather, is very important.” “It simply came to our notice then. Throughout the year, it tells us when the crops will ripen. So this is very important, especially for historical civilizations. “
From yuzu baths in Japan before You are Raymi celebrations in Peru, the world’s cultures have a long history of celebrating the winter solstice. Modern druids and archaeologists in England continue to focus on the Stonehenge monument at this time of year. The interests of the two groups sometimes agree, but often diverge on issues such as showing human remains found at Stonehenge.
Many traditions of the winter solstice include the use of food to unite families and communities. Version of pie with minced meat may have been eaten during the holidays in Stonehenge. The Dongzhi Chinese Festival is famous for tangyuan, rice dumplings, often stuffed with black sesame seeds.
Although the holiday is celebrated earlier in December, St. Lucia’s Day in Scandinavia dates back to the winter solstice. Butter saffron rolls twisted in an S-shape and accented with raisins are consumed as part of St. Lucia’s Day activities.