Christmas Countdown, Sunday #2

Day 10

Sunday’s theme is a reminder that there are more holidays than just Christmas in December — or in the winter in general, so we’ll be going to another continent for this one. Now, why are there so many holidays this time of year?

Simple. Astrophysics.

The very basic version of this is that the Earth rotates around its axis, which you can imagine as a stick that goes from its north to south pole. (Illustrated version available here.) The Earth is perfectly happy to rotate around this axis at a rate that gives us one revolution per day. While the Earth rotates around its axis, it also orbits the Sun, and this takes about 365.25 days (which is why Leap Years exist, but that’s not relevant here.)

Now if the axis were straight up and down — meaning that the equator was exactly level with the Earth’s orbit, we’d have no seasons and all days would be the same length. However, it’s not. It’s tilted about 23 degrees. This means that as the Earth goes around the Sun, the angle at which light hits it changes. On the first day of spring and first day of fall (in the Northern hemisphere), the axis is straight up and down relative to the orbit, so day and night are of equal length. As spring progresses into summer, the axis (in the north) tilts toward the Sun; from fall into winter, it tilts away. Tilting toward makes days longer; tilting away makes them shorter.

In winter, the days become the shortest of all, and the winter holidays, like Christmas, tend to happen right around that longest night of the year, which is the Winter Solstice, generally around December 22nd now, but a few thousand years ago it was closer to the 25th.

But the salient bit is this: Once the solstice comes and goes, the days after that start to get longer, light returns, and the world is eventually reborn in spring. All of these winter festivals are partly a way for communities to come together at the darkest and coldest parts of the year, and partly a way to remind them that it’s going to get better soon.

Which brings us to Diwali, which happened in mid-November (in America) this year, although it’s a holiday celebrated by Hindus, Sikhs, Jains and some Buddhists around the world. Basically, it celebrates the triumph of good over evil, and prominently features, well… lights, since it’s the festival of lights. But it definitely fits the winter theme, and again you can see how astronomical realities can dictate social conventions. When the year gets dark, we celebrate the fact that the light will always win and return.

Don’t forget to check out the previous post or watch the next.

Wednesday Wonders: Does anybody really know what time it is?

As clocks are being set back in a lot of places during this week, here’s a reminder of why DST and Time Zones are things, and while not every country has more than one of the latter or observes the former.

Last weekend, a lot of countries ended Daylight Saving Time and switched their clocks back to Standard Time, with other countries making the change next Sunday, on November 7.

Generally, the places changing earlier are in Europe and the ones changing later are in North America and surrounding island nations, but this only applies to the Northern Hemisphere and to countries which actually use DST, which a surprising number do not.

If you’re in the Southern Hemisphere, then the dates are completely different, with most places having started in September and ending DST in April, although this still observes the “spring ahead, fall back” advice.

Why we still do Daylight Saving Time — or switch back to Standard Time, which suddenly plunges us into nightfall way too early — is a mystery, especially in this age of instant communication, artificial lighting, and remote work that allows us to collaborate in real time with people around the globe.

For example, in my day job, I am constantly in communication with people here in Los Angeles with me, as well as in Oklahoma, New York, Florida, Israel, and Pakistan. Of course, when my work day begins around 8:30 or 9:00 in the morning in California, it’s 12 hours later in Pakistan, so we’re literally working on opposite schedules.

Israel is normally 10 hours ahead of us, but since they changed their clocks a week early, they’re currently 11 hours ahead. Pakistan hasn’t done DST since 2009, so that doesn’t change.

The concept of DST has nothing to do with farmers, though, as the popular misconception goes. No, you can blame the Germans for it. They first set their clocks ahead in 1916, so probably a lot later than you were thinking.

The reason the Germans did it was because they were in the middle of WW I and wanted to cut down on the need for artificial lighting, thereby saving fuel to go toward the war effort. Other countries followed suit within a couple of years, including the U.S. — but it wasn’t consistent in the U.S.

DST here was an on-again, off again thing, not becoming the norm until fifty years after Germany started it, and with different local laws and customs between states and even divisions within states. Congress finally stepped in with the Uniform Time Act in 1966.

Time Zones, on the other hand, came about a lot earlier than Uniform Time, having started in the U.S. in November, 1883 for one simple reason: Railroads.

Prior to that, most locations marked their time by calling it “noon” when the Sun was directly overhead, which was fine when people only traveled on foot, on horses, or in horse-drawn wagons. But as soon as the relatively high-speed form of transit called the locomotive came about, that all had to change.

Why? Because it made it very difficult to create coherent schedules otherwise. Every fifteen degrees of latitude you go (distance around the Earth), there’s a one-hour time difference in local noon.

At the average latitude of the continental U.S. (39°50’N), each degree you move in either direction translates into 53.4 miles (86 kilometers), representing 1/15th of one hour, or a 4-minute time difference.

If your train’s next stop is 250 miles away, then time there as determined locally would be off by almost 19 minutes from your previous stop. So — which time do you use on the schedule? Local time from where the train first departed? Local time at its destination? Local time at each stop?

That could quickly become an impossible mess, and double that because westbound destinations will have times earlier than where the train came from, and eastbound will be the opposite.

The solution was to divide the country up into uniform time zones, each one roughly 800 miles wide to approximate the 15 degree per hour difference, although they generally tended to also respect state borders.

Now, a train could travel a fair distance within one time zone, and conductors would only have to remind passengers occasionally that their arrival location would be one hour later or earlier than where they’d come from. Ta-da!

We still see that to this day when our pilots remind us what time zone we’re landing in after a long flight and, of course, thanks to GPS, our phones will make the adjustment for us. I do appreciate it very much that ever since smart phones (and that my bedroom clock also does it automatically), I’ve only ever had to to manually change the time on my stove, microwave, and car since forever.

And why they don’t design those devices so you can change the hour in either direction is beyond me, especially when you can’t change the hour directly, but have to roll through the minutes. Really?

But the nice thing about having a few time zones across a wide country is that it allows people locally to pretty much align their day with sunrise and sunset while still knowing what time it is for distant colleagues.

There’s one place, though, where everybody knows what time it is, and it’s pretty insane considering that the country used to have five time zones (because it was that wide) up until 1949.

That date may strike you as significant if you know your history, and if you’re thinking of China, you’re right. Despite its size from east to west, since 1949, China has had exactly one time zone, Chinese Standard Time, and it’s set for Beijing, defined as UTC (or GMT) + 8 hours.

This leads t1o some pretty insane things, like the time difference across the China/Afghanistan border. If you cross west from China into Afghanistan, it’s suddenly 3 1/2 hours earlier. This can also lead to some pretty funky daylight hours for people, with sunrise coming as late as 10:16 a.m. in the west and as early as 6:54 in the east during winter, and sunrise as early as 7:44 p.m. in the west and 3:16 p.m. in the west. During the summer, sunset comes as late as 10:26 p.m. in the west and 7:08 p.m. in the east, with sunrise at 7:34 am in the west and 3:05 a.m. in the east.

So, as you can see, in some places, people have to get used to really weird daylight hours. Combine that with practically the entire country going on vacation for the month of February, with workers from rural areas returning from the cities to their families, perhaps to never go back to their jobs because they made a fortune working in factories to satisfy the holiday needs of Westerners, and I do sometimes wonder how China ever gets anything done.

That last little bit is from firsthand knowledge, by the way. I used to work with logistics people who dealt with getting products to my company, a lot of them from China, and February was a pain in the ass every single year. If we were going to run out of inventory from there around that time, we had to over-order back in October and hope that we could get it all shipped by mid-January.

And that was without seemingly every cargo container ship in the world stuck offshore somewhere.

So, if you’re in a country with a few logical time zones, or in one that only has one zone because your borders are all within the 15 degree limit more or less, consider yourself lucky — doubly so if your country doesn’t mess with changing the clocks twice a year.

By the way, the second largest country with only one time zone is… India. However, it’s only about 30 degrees wide, so while it should technically have two zones, each one hour apart, it’s nowhere near as strange as the situation in China, and it’s only one hour behind Afghanistan, which is what it should be.

At least you’re not living in a place where every 13-minute drive can change your local time by a whole minute.

Good day, India!

I’ve noticed over the last few months that I have quite a few readers from India, and first I wanted to say “Welcome!” Second, I wanted to ask what brings you here, and what I can provide in the way of content to improve your experience — or if what I’m doing works for you already.

So don’t be shy. Check in in the comments below, or click to send me a private message. It just amazes me that I seem to be connecting with and have followers from half-way around the world — which is kind of the point of the internet in the first place, isn’t it?


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