First Day of 2016: 5 Facts You Need to Know

 

The first day of winter, and the 2016 winter solstice, are being celebrated with a Google Doodle on December 21, 2016.

“Across the northern hemisphere, people everywhere celebrate the winter solstice with seasonal holidays, celebrations, and festivals to remind us of the lengthening days ahead. The solstice is named for the brief time when the sun appears to pause its movement across the sky,” Google says. “At that moment, the tilt and rotation of the earth shifts our view of the sun’s direction from southward to northward, causing it to hang momentarily suspended.

“Doodler Nate Swinehart created a family of anthropomorphized rocks to commemorate the winter equinox. After tonight’s long darkness, we’ll look forward to the sun hanging out a little longer each day,” Google says.

Here’s what you need to know:

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1. The Winter Solstice Occurs When the Sun Appears at Its Southernmost Point

The winter solstice occurs when the sun appears at its most southerly position, directly overhead at the Tropif of Capricorn, according to NASA.

It is the longest day of the year in the Southern Hemisphere.

“Because the Earth is tilted, we experience seasons here on Earth. As the Earth moves around the sun, each hemisphere experiences winter when it is tilted away from the sun and summer when it is tilted toward the sun,” CNN senior meteorologist Dave Hennen said. “Scientists are not entirely sure how this occurred, but they think that billions of years ago, as the solar system was taking shape, the earth was subject to violent collisions that caused the axis to tilt.”

The solstice occurs on the same moment everywhere on Earth, but it is observed at 24 different times of day because of the world’s 24 timezones, according to National Geographic.

 

The astronomical winter starts December 21 and ends March 19, according to the Met Office, the United Kingdom’s national weather service.

“The astronomical calendar determines the seasons due to the 23.5 degree tilt of the Earth’s rotational axis in relation to its orbit around the sun. Both equinoxes and solstices are related to the Earth’s orbit around the sun,” the Met Office says. “Solstices and equinoxes are considered to be the astronomical transition points between the seasons and mark key stages in the astronomical cycle of the earth. In a year there are two equinoxes (spring and autumn) and two solstices (summer and winter).”

 

“The dates of the equinoxes and solstices aren’t fixed due to the Earth’s elliptical orbit of the sun,” according to the Met Office. “The Earth’s orbit around the sun means that in early January, the sun is closest (known as perihelion) and in early July it is most distant (aphelion).”

2. The First Day of the Meteorological Winter — December 1 — Has Already Passed 

The first day of the meteorological winter has already passed. That came on December 1. The winter solstice is the first day of the astronomical winter.

“Astronomical seasons are based on the position of the Earth in relation to the sun, which is what most people grew up learning. In my world, meteorological seasons are based on the annual temperature cycle,” meteorologist Kevin Arnone, who works at WTNH-TV in Connecticut, says.

According to Arnone, the National Oceanic and Atmospheric Administration explains, “The meteorological seasons were created to make observing and forecasting purposes easier. To make things easier, the length of the seasons is also more consistent for the meteorological seasons, ranging from 90 days for winter of a non-leap year to 92 days for spring and summer. It makes it much easier to calculate seasonal statistics from the monthly statistics, both of which are very useful for agriculture, commerce, and a variety of other purposes.”

The Weather Network meteorologist and science writer Scott Sutherland says the meteorological winter helps keep accurate records:

When it comes to keeping climate records, it does, especially if you want consistency (and we do!). Astronomical seasons can last anywhere from 88 to 94 days (depending on the year and what time-zone you live in). So, rather than having to account for that difference in length when you’re comparing seasonal averages, each meteorological season has the same length as the previous year’s, and they’re much closer in length to each other throughout the year as well. Meteorological springs and summers are 92 days long, autumns are 91 days long and winters are 90 days long (or 91 every four years, due to the Leap Year). Reverse all of that for the southern hemisphere, but they’re just as regular.
Also, by setting those as the dates for meteorological seasons, it allows the records to capture the weather that’s most associated with that season. For example, for winter, you really want to be recording the coldest part of the year. The northern hemisphere is generally cooling down as the calendar ticks away towards the winter solstice in December, and it’s starting to warm up (overall) again as the calendar approaches the spring equinox in March.

Derek Arndt of the National Climatic Data center told the Washington Post the meteorological winter has been around,” since the early-to-mid 20th century, when it really took root in the applied weather and climate communities.”

Arndt told the Post, “dealing with whole-month chunks of data rather than fractions of months was more economical and made more sense – and still does, in many ways. We organize our lives more around months than astronomical seasons, so our information follows suit.”

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3. Winter Solstice Festivals Date Back to Ancient Civilizations & It Is Still Celebrated Annually at Stonehenge

 

One of the most well known celebrations of the winter solstice occurs each year at Stonehenge in England. Druids, pagans and others gather each year to witness the sunrise.

“This is the dawn we’ve been waiting for, this is the dawn the ancients cared about so much,” Senior Druid King Arthur Pendragon told the BBC during last year’s celebration. “After this they knew the days were going to get longer and the return of hope and renewal.”

England Heritage told the BBC that Stonehenge is the site of the celebration because of its alignment with the sun.

“One of the most important and well-known features of Stonehenge is its alignment on the midwinter sunset-midsummer sunrise solstitial axis,” a spokesman for the organization said. “The midwinter sun sets between the two upright stones of the great trilithon. We do not know which solstice was more important to the users of Stonehenge, but several pieces of evidence suggest that midwinter was very important.”

In addition to the Stonehenge ceremony, the winter solstice was celebrated by ancient civilizations in several other areas of the world, according to National Geographic.

Scandinavians celebrated Juul or Yule, a multi-day feast marking the sun god’s return.

The Dongzhi festival in China marked the time when winter’s darkness began to give way to light. It is still observed today, with families eating special foods.

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4. Christmas Might Have Its Roots in Pagan Solstice Celebrations

Some historians believe Christmas is likely celebrated on December 25 because of its roots in a Roman solstice celebration. According to that theory, early Christians adopted the pagan celebration of Sol Invictus.

Theologian Andrew McGowan explains that theory in an article in the Biblical Archaeology Society:

The most loudly touted theory about the origins of the Christmas date(s) is that it was borrowed from pagan celebrations. The Romans had their mid-winter Saturnalia festival in late December; barbarian peoples of northern and western Europe kept holidays at similar times. To top it off, in 274 C.E., the Roman emperor Aurelian established a feast of the birth of Sol Invictus (the Unconquered Sun), on December 25. Christmas, the argument goes, is really a spin-off from these pagan solar festivals. According to this theory, early Christians deliberately chose these dates to encourage the spread of Christmas and Christianity throughout the Roman world: If Christmas looked like a pagan holiday, more pagans would be open to both the holiday and the God whose birth it celebrated.

But McGowan says there are issues with that theory, despite its popularity.

“Early Christian writers never hint at any recent calendrical engineering; they clearly don’t think the date was chosen by the church. Rather they see the coincidence as a providential sign, as natural proof that God had selected Jesus over the false pagan gods,” McGowan writes.

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5. The Earliest Sunset & Latest Sunrise Don’t Fall on the Winter Solstice

The winter solstice is not the earliest sunset of the year, as that comes a few days earlier, because the sun and human clocks don’t match up exactly, National Geographic says:

We’ve organized our days into precise 24-hour segments but the Earth doesn’t spin on its axis so precisely. So while the time from noon to noon is always exactly 24 hours the time between solar noons, the moment each day when the sun reaches its highest peak, varies. So as we move through the year the chronological time of the solar noon shifts seasonally—and so do each day’s sunrises and sunsets. During December, solar noons can be some 30 seconds longer than 24 hours apart. That means while the shortest amount of total daylight falls on the solstice the day’s sunset is actually a few minutes later on our clocks than it had been earlier in the month—because both sunrise and solar noon have also occurred later in that chronological day than they had in days earlier in December.

Justin Grieser of the Washington Post’s Capital Weather Gang, says the earliest sunset comes about two weeks before the solstice, while the latest sunrise isn’t until early January.

“The succinct explanation is that solar noon — the time the sun reaches its highest point in the sky each day — moves several minutes later in December, a phenomenon caused by Earth’s planetary tilt and elliptical orbit around the sun,” Grieser writes. “When the sun takes more than 24 hours to reach the same point in the sky from one day to the next, we start to see a lag between our 24-hour clocks and the sun’s apparent daily motion in the sky. This discrepancy pushes sunrise and sunset times later even as the days continue to shorten right up until the solstice.”

Grieser adds, “But even though our latest sunrise and earliest sunset don’t neatly coincide with the shortest day of the year, remember that the days will slowly start to get longer now. So if the dark days of winter are getting to you, rest assured, it only goes up from here — and that’s something to celebrate.”

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