Everything Everywhere Daily: History, Science, Geography & More - The Winter Solstice

Episode Date: December 22, 2022

Twice a year, the sun reaches an extreme point in the sky. It is the day with the least amount of sunlight or the most amount of sunlight, depending on where in the world you happen to be.  It is a day that almost every early culture around the world recognized because it was the one day a year they could document by following the path of the sun.  Learn more about the solstice, how it works and how it has been celebrated on this episode of Everything Everywhere Daily. Subscribe to the podcast!  https://link.chtbl.com/EverythingEverywhere?sid=ShowNotes -------------------------------- Executive Producer: Darcy Adams Associate Producers: Peter Bennett & Thor Thomsen   Become a supporter on Patreon: https://www.patreon.com/everythingeverywhere Update your podcast app at newpodcastapps.com Discord Server: https://discord.gg/UkRUJFh Instagram: https://www.instagram.com/everythingeverywhere/ Facebook Page: https://www.facebook.com/EverythingEverywhere Facebook Group: https://www.facebook.com/groups/everythingeverywheredaily Twitter: https://twitter.com/everywheretrip Website: https://everything-everywhere.com/everything-everywhere-daily-podcast/ Learn more about your ad choices. Visit megaphone.fm/adchoices

Twice a year, the sun will reach an extreme point in the sky. It's the day with the least amount of sunlight or the most amount of sunlight, depending on where in the world you happen to be. It's a day that almost every culture around the world recognized because it was the one day a year they could document by following the path of the sun. Learn more about the solstice, how it works, and how it's been celebrated, on this episode of Everything Everywhere Daily. What if your perceptions about the past were wrong?

throughline is a podcast that takes you back in time to uncover the parts of the story that may have gone unnoticed. It effectively turned day into night and how it shaped the world now. Time travel with us every week on the ThruLine podcast from NPR. Let me start up by noting that the solstice is not a day. While we recognize it as a day because it happens to result in the longest or shortest day of the year, In reality, the solstice is just a moment. In fact, if you wanted to get really technical, you could pinpoint the moment of the solstice down to the very second. So what exactly is this moment which is called the solstice?

There are two solstices each year, a winter solstice and a summer solstice. Which is which will depend on what part of the world you live in. A solstice is when either pole of the earth is pointed at its maximum angle towards or away from the sun. If one of the poles is pointed away from the sun, that hemisphere is having its winter or hibernal solstice. If it's pointed towards the sun, it's having its summer or estival solstice. When it is the winter solstice in the northern hemisphere, it has to be the summer solstice in the southern hemisphere, and vice versa. The solstice has everything to do with the tilt of the earth. The solar system has an imaginary plane running through it called the ecliptic plane.

This is the plane on which the average location of the Earth's orbit rests. The Earth's axis is tilted approximately 23.4 degrees off of the ecliptic plane. And if you really want to get technical, the tilt of the Earth is 23.4365-472133 degrees away from the plane. The poles are orientated at the same point in the sky, which is why the North Star is the North Star all year long. The tilt of the Earth's axis, plus the fact that the poles point at the same point in space, is what results in the seasons. If the Earth had no axial tilt, there would be no seasons. If one pole were always orientated towards the sun, one pole would be in perpetual light and the other in perpetual darkness,

and again, there would be no seasons. The date on which the solstice occurs isn't always the same. There are a couple of reasons why this is the case. The first is because the solstice is a moment in time. What time it is can differ on different parts of the Earth due to the time zones. The other reason why it doesn't occur at the same time every year is that the number of days doesn't equally divide into a year. This is the reason why we have leap years.

So if we just go by Universal Time or UTC, the winter solstice in the Northern Hemisphere occurs on December 21st for three years and then on December 22nd every fourth year. The axial tilt of the earth being responsible for the seasons and the solstices is something I'm sure most of you already know. What most people don't know is that the solstice and the seasons are slowly changing over time. In a previous episode, I talked about the Milankovic cycles and the idea of procession. If you think of a spinning top, as the top is spinning, it may also have a slight wobble to it. The orientation of the axis of the top will move as it's spinning. This is procession.

Just like atop, the Earth's spin has a wobble in it, but it wobbles very slowly. The Gregorian calendar is designed to track the tropical year, so equinoxes and solstices always occur at roughly the same time. However, and here I'll refer you to my episode on the Gregorian calendar, while it fixed the big problems with the Julian calendar, the Gregorian calendar still isn't perfect. over time, unless there is a future correction, solstice dates will continue to creep backwards. For example, in the year 2048, the Northern Hemisphere Winter Solstice will actually take place on December 20th. Over thousands of years, without a calendar correction at some point, the dates will keep moving back. This really isn't a pressing issue, but around the year 4,000, and multiples thereof, it might be necessary to not have a leap year, whereas normally it would be a leap year. year. And likewise, it might be necessary to have an exception to that rule every 20,000 years,

but that isn't really something that we have to worry about. Assuming calendar issues aren't a problem, the solstices will still occur at the same time in the calendar, but they're going to be in a different part of the sky. Right now, the date of perihelion, which is the point at which the earth is closest to the sun, takes place around January 2nd to January 4th, reasonably close to the Northern Hemisphere winter solstice. However, in the year, 15,021, that same solstice will occur at Apheelian, which is the point where the earth is furthest from the sun. There's one other thing that's slowly changing over time, the tilt of the earth. The tilt of the earth changes over a period of approximately 41,000 years, from 22.1 degrees to 24.5 degrees. Currently, the earth is in a period where

the angle is decreasing, meaning that over the next several thousand years, seasons will become less extreme. This will also mean a change in the location of the tropics of cancer and Capricorn, as well as the locations of the Arctic and Antarctic circles. All four of these lines are determined by the axial tilt of the earth. The tropical lines are the same number of degrees from the equator as the tilt, and the polar lines are the same number of degrees from the poles. So, okay, the solstices are determined by the tilt of the earth, which is moving, but that's something we'll never have to worry about in our own lifetimes. But a solstice isn't just a geophysical phenomenon. It's also a cultural one. In fact, a solstice

has the unique distinction of being a non-religious, non-cultural-specific event that's almost universally recognized and celebrated. Some of the very earliest evidence we have of human construction and by extension civilization are structures built to align with the winter solstice. If you remember back to my episode on Gobeki Tempe, this is probably the oldest structure that we know of in the world, dating back 11 to 12,000 years. There are some who think that this might have been, at least in part, designed to track the winter solstice. Stonehenge was built to track the winter solstice. Cahokia, the largest city north of Mexico along the Mississippi River, built what has become known as Woodhenge to track the solstice. The Intihuitana stone at Maccichu in Peru tracks the solstice.

A stone ring was found in Australia by the Wada Wurung people, which tracks both solstices. In Egypt, the Temple of Karnak is aligned with the Winter Salstice, as is the Mayan Temple at Tulum. One of the most interesting ancient sites designed to be aligned with the winter solstice was the site of New Grange in Ireland. New Grange is basically a large 5,200-year-old mound with a single opening. And you can visit the site pretty much any day of the year and go inside, but there isn't room for that many people. However, the singular entrance into the mound is aligned perfectly such that the interior of the mound is illuminated by sunrise on the winter solstice and the two days surrounding it.

And if you want to experience the inside of the mound on the solstice, you have to enter a lottery that tens of thousands of people enter every year, and only 10 people are allowed inside on each of the five days. So why build these structures to track the solstice? In addition to just calendar planning and tracking, they were probably celebrations that were tied to the solstice. Midwinter and midsummer celebrations are almost ubiquitous for any culture which isn't located that close to the equator. Ancient Rome had the festivals of Saturnalia and Solenvictus, and Saturnalia was a wild celebration where social roles were reversed. The Incas had a winter solstice celebration known as Inti-Ramey. They would fast for three days before the solstice and then greet

the dawn with gifts and sacrifices for the gods. They said, celebrated in June, of course, because they were in the Southern Hemisphere. Ancient Persia had their celebration for the god Mithra, who was the god of light. Ancient Scandinavians had a celebration called Yule, where they would burn logs when the days were short, and these were the basis of the Yule log, which some people still use today. Solstice or midwinter celebrations aren't just a thing of the past, however. They're still celebrated around the world today. In Scandinavia, they now celebrate St. Lucia's Day. It involves the lighting of fires

and girls wearing white dresses with wreaths on their head with lit candles. In China, it's known as Dongji. It's a time for families to get together and they commonly eat glutinous rice balls. In Iran, they celebrate Yaldonite, which involves eating food such as watermelon nuts and pomegranates, staying up late and reading poetry. In Japan, they have toji, which involves the lighting of bonfires, especially on Mount Fuji, as well as taking hot baths, often in hot springs. The amazing thing, of course, is that all of these cultures,

and civilizations, despite celebrating in radically different ways, all did so on the same day. Before I end, I wanted to address one common misconception people have about both the summer and winter solstice. People often assume that if the solstice is the longest or shortest day of the year, then it must also be the hottest or coldest day of the year. And this is not the case. While this would make some sense at first, the reason why it isn't the coldest or hottest time of the year is because it takes time for the atmosphere to warm up and cool down. Extreme temperatures usually take place about a month after each salsus, but there's obviously a lot of variation in that depending on specific weather circumstances.

A solstice is a unique event in that it's a universal experience. Not only is it something that everyone on the planet can share in, but it's something that has been experienced throughout all of human history. The executive producer of Everything Everywhere Daily is Charles Daniel, the association Associate producers are Thor Thompson and Peter Bennett. Today's review comes from listener Moyer Jr. 7 from Apple Podcasts in the United States. They write, Keeps my tired mom brain sharpish.

I've enjoyed this podcast for many months, but I'm finally leaving my five stars in a review after your episode on Paracoutin. I saved it to listen to with my almost six-year-old Luke who's fascinated by volcanoes. While I'm not yet part of the Completionist Club, he and I have listened to the Paracutin episode at least 10 times. What higher praise than, this podcast keeps an energetic kid sitting still and fully enthralled for 10 minutes. Thank you from a very tired but proud mom. You help my brain wake up every morning as well as my kids.

Well, thanks, Moyer Jr. 7. Even though you are not yet a member of the Completionist Club, if I were giving out merit badges for listening to the show, you'd have to earn one for listening to the same episode 10 times. As far as I know, that's a record. Also, if you have a five-year-old who's already interested in volcanoes, I would say that you are doing a pretty good job at being a mom. And you'd also get a merit badge for that. I hope that you and Luke keep listening. Remember, if you leave a review, you two can have it read on the show.