Tuesday, December 22, 2015

Greeting the season

The December Solstice was at 5:49pm NZDT, making today the longest day of the year, and some 5 hours, 4 minutes longer than on the June Solstice. Today will also be about three seconds longer than yesterday—whoop! Plenty of extra daylight to get things done!

Seriously, I saw a lot of people posting on Facebook yesterday, saying that was the longest day. I think the confusion arises because the date and time of the solstices are variable.

Similarly, the amount of daylight gained or lost varies, too. Today we got an extra three seconds, but yesterday we got six, the day before nine seconds. Going the other way, tomorrow will have one second less daylight, the 24th will have four seconds less, the 25th gets eight seconds less, and so on each day until June, when the process reverses again.

This is all caused by Axial tilt, the fact that the earth is about 23.4 degrees off vertical (relative to the ecliptic plane), and that causes all our seasons. Astronomical solstices and equinoxes are celestial events, and don’t necessarily have any relationship to weather—temperature may be affected, the amount of daylight definitely is, but in this part of the world, as I say all the time, our meteorological seasons begin on the first of the month (Summer began December 1, Autumn begins March 1, and so on).

The difference in seasons between the two hemispheres is also why it’s not commonly accepted practice to refer to the December Solstice and June Solstice, because “Summer” and “Winter” are relative to which side of the equator one is on when the Solstice arrives.

All of which relates to the graphic above. It’s based on a popular Internet meme spread by science nerds, atheists and agnostics, and people who like to needle self-centred Christians. Too many Christians, completely unaware of the non-Christian origins of practically everything about their celebration of Christmas—including the very day it’s celebrated on—like to say that “Jesus is the reason for the season”. If they want to make their Jesus the focus of their celebrations, that’s their choice, but to a great many people, their declaration about the meaning of the season is irrelevant.

The reason for all seasons—including the one this month—is axial tilt. The reason for many of our holiday traditions this time of year is that we “borrowed” them from pagans and other non-Christian traditions. And that’s why someone people like to gleefully spread memes similar to the one above.

I originally made my version because I was uncertain about who created the ones I was seeing, and what their copyright status was, so I made my own. I put the word “SEASON” in all caps to emphasise that I was being pedantic about the science, even though I knew that the people most likely to be offended would never even notice.

It is, if I’m honest, a particularly snarky meme, one that mocks certain Christians for no particularly useful reason other than pedantry, maybe. But in recent years there’s been a growing willingness among secularists of all kinds—atheists, agnostics, non-theists, and religious people who want firm separation between church and state—to assert our right to celebrate Christmas, too, and without any religious overtones. Memes like this serve to remind certain Christians that this holiday, with all its pagan origins and trappings, doesn’t actually belong to them alone.

So, Christians who are offended by this meme, or by the idea of people who don’t believe as they do celebrating Christmas, need to remember that religious freedom means freedom for all, and that includes citing different reasons for the season.

Season’s Greetings!

Related: I covered some of this territory in December, 2012.

I created the graphic with this post using an image in the public domain. I claim no ownership over that image, but the composition is licensed under my usual Creative Commons license.

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