Time and Holidays

Time and Holidays

By Bob Billing
SF Moderator

©2001, Bob Billing

European tourist in Oxford: Please - what is time?

Philosophy professor, after thinking for a while: That's a very interesting question, one to which we don't have a definitive answer. However...


Time comes in different flavours. There's solar time, atomic time, universal co-ordinated time, sidereal time, bedtime and harvest time - before we even start on those created for science fiction.

We don't really know when mankind first started trying to tell the time. Possibly it all began when womankind started telling mankind that he was late and the children were hungry. The sun rose, the sun set. It stayed up longer in summer than in winter. The moon grew and dwindled away in a regular cycle. The burning skeins of stars made clear nights a time of beauty and wonder, their patterns moving on by a barely perceptible step each evening.

What mattered was the hunting, and later on the farming - in a primitive society, food comes before philosophical speculation. However, sooner or later someone was bound to point out the obvious - the migrating geese, the ones that were good eating, came at the same time every year. And every year, when the geese came, the rising sun was just a little bit to the right of the tree on the nobbly hill. It didn't take a genius to work out that if the whole tribe started making arrows when the rising sun was still just to the left of the tree it'd be raining campfire-ready geese a few days later.

A thousand little discoveries later, each one backed up by heaps of goose bones, fields of corn or tons of smoked elk, astronomy was born.

There must have been an overwhelming sense of power running through the early astronomers. For the first time someone could predict. By finding regularities, counting off days and months, they could say that there would be high tides on a particular night, or that the geese would arrive in three weeks.

For the first time the human race could grab control of its destiny. Instead of accepting whatever the world chose to throw at them, the citizens of our early society could know what was coming and prepare for it. In a real sense this was what made them human.  Passive acceptance of fate was obsolete; this was the dawn of the age of engineering.

Of course nothing is that easy. The step-dance of the lights in the sky was perfectly regular and utterly frustrating. A new moon appeared every twenty-nine and a half days. Then one would be a day late. The ratios connecting the movements of the sun, moon and planets weren't convenient, sensible numbers. Puzzling them out needed better oberving instruments, followed by improved systems of mathematics to reduce the observations.

Better instruments revealed even more complex patterns. Once pendulum clocks were accurate enough to agree with one another, the strange behaviour of the sun showed up. The sun gained and lost  time as well; solar time swung ten minutes either side of clock time during the course of a year.

Even more interesting was the behaviour of the stars. Apart from the few little dots of light that wandered around and were called "planets" - from the Greek word for "wanderer" - most of the stellar background was fixed. But night after night it stepped forwards a little.

Now it was time to find some explanations. The daily cycle of sunrises and sunsets is caused by the rotation of the Earth. But at the same time it's orbiting the sun every year. The earth has a tilt - its axis of rotation doesn't stick straight up out of the plane of its orbit. The northern hemisphere points in towards the sun in June. That's the British summer when we lose at cricket to the Australians. The southern hemisphere points at the sun in December, the Australians have their summer and we lose at soccer to any nation that's passing. The Earth's orbit isn't perfectly circular, but an ellipse. The Earth is closest to the sun around January and furthest away around July. This has an effect on the seasons, small compared to the effect of the axial tilt, but large enough to measure.

The Earth is both rotating and going around the sun. If you measure the length of a day by how long it takes the stars to get back to the same places in the sky, you don't get the same result as if you take the mean time from one solar noon - when the sun is highest in the sky - to the next. The Earth goes around the sun in the same direction as it rotates, so in a year that the sun goes around the sky 365 times, the stars go around 366 times.

This is the difference between solar and sidereal time. Solar time is measured by the sun, sidereal time by the stars. The sidereal day is a little under four minutes shorter, so the stars rise and set earlier each day.

Things got much worse with the invention of the atomic clock. Good old Greenwich Mean Time had been defined in terms of the movements of the sun as seen from Greenwich. The various atomic clocks around the world all agreed with one another - they could be synchronised by radio - and they all told the same story. The Earth was speeding up and slowing down. Our definition of the length of a second, based on observations from Greenwich, was built on foundations about as solid as soft cheese.

This is why the world has changed from GMT to UTC. Now the length of a second is defined in terms of the atomic clocks and from time to time "leap seconds" are added or removed to keep UTC in step with the Earth.

Now we have enough information to start worldbuilding. We can tinker with the parameters of an imaginary planet and see where they take us. For example:

Sinclair's eyes closed for a moment. "Eastern side and well in towards the galactic core. Isn't there something odd about its orbit?"

Jane nodded. "No axial tilt to speak of - Greenworld doesn't have any seasons. There's a temperate belt round the equator which is populated, then it shades off into darker and gloomier forests as you head for the poles. The trees grow with no annual rings, which makes the wood an expensive rarity."

There are two ways we can go from here. Either our imaginary planet is part of a larger, interplanetary civilisation, or it's more or less isolated. In the first case the inhabitants will want to try to share holidays and festivals with other planets; they'll want the sense of solidarity that comes from thinking that as we sit down here to celebrate Homeworld Day, cousin George on St. Barbara is doing the same thing. Making this work will involve using a calendar that's based on something other than the rotations and orbits of individual planets. Greenworld again: 

[Jane] "Atomic clocks. They work out which day comes closest to Christmas on the theoretical Old Earth, what it would be if it hadn't been nuked into a different spin in the long war. Then they build all the festivals around that." She put her drink down and pressed buttons on her heavy gold wristwatch. "We've timed it right. In about ten minutes it'll be midnight, Old Earth, or nearly eleven in the morning here. The children will come on and do a little play, then we all go through for lunch - which will take most of the afternoon."

In this case the festivals will largely be created as commemorations of people or events. It's then up to the government of your imagined planet to decide who is worthy of being remembered and which events they want people to have in their minds. Remember that this sort of festival will come at a different time each year because it's based on a calendar that has nothing to do with the orbits of the planets where the celebrations are.

Let's consider a starship carrying colonists to another planet. Even though they'd travel in suspended animation, they'd take with them tins and packets of food to eat when they arrived, because it would be a while before they could produce their own. Sooner or later the stores would run out. It'd either be a moment of release - they knew they were self-sufficient - or a moment of terror if they weren't. I suspect that the instant of opening the last tin would be a cause for celebration. It might even be caught on camera: 

"We are able to produce a great deal of our own food in the atmosphere domes. Not as much as we would like, which is why we've delayed bringing the rest of our people out of suspended animation. It's been a delicate juggling act, trying to make sure we could produce each commodity ourselves before the supplies we brought from Old Earth ran out. Today we come to the end of one of our stocks." Genevive held up the tin. "This is the very last of the tins of condensed milk we brought with us from Old Earth. And on this tray are the teacups belonging to the people who are working in the domes." She pulled the ring on the tin and began to pour. "I can stretch this tin to ten or so - no more." She picked up the teapot and filled the cups. "Egil - if you'd like to take the tray out to them?"

Egil Lund picked up the tray and left.

Genevive went on. "That leaves me with no milk for my tea." She looked directly into the camera, a faint, prim smile on her face. "Or it would, were it not for this." She reached out of shot and picked up a jug. "Our own milk, from our own cattle kept in our own atmosphere domes." She poured the tea and took a sip. "This is the moment of transition. We are now free. Truly free." She froze, holding the cup.

From this little moment could come a sacred tradition:


And that's why if you're anywhere on the nine worlds of the Arcturian Confederation on the first Wednesday in March - subject to the usual confusion about calendars - you'll find that it's a public holiday called Homeworld Day. Many businesses will be closed, but if you find one that is open, or you are invited into someone's home, you'll be offered a small cup of hot, sweet, milky tea with the words, "We are now free." To be polite take at least one sip and reply, "Truly free."

There is another sort of holiday, the one that comes from the slow turning of the seasons. Normally this would be restricted to the one planet where it made sense, but I can see a possible future in which one planet is home to the capital of a galactic empire and imposes its public holidays on everyone else. Holidays of this kind would tend to grow out of the cycles of agriculture and hunting, but they might persist long after most of the population has moved away from direct involvement with the land. For example, the sun rises a little further to the right each morning as we go deeper into winter, until around the 21st of December it stops. On the 25th it visibly moves to the left. This day the Romans called the "birthday of the unconquered sun", and they celebrated it as the beginning of the new year. Having no record of the date of the birth of Jesus, the Christian church has borrowed the date from the pagans as Christmas Day.

There is a little problem that comes from writing about a Galactic Empire peppered with planets, each of which has a different length of year.  How do you know someone's age? Can the young lad who's just arrived from another planet have a licence to drive a hovercar? Is the girl with him entitled to be served in the bar? And are they old enough to be legally married? The only solution I've ever found is this:for legal purposes everyone uses a clock and calendar based on a theoretical Earth, but in fact derived from atomic timing. Printed calendars use the local dating scheme which divides the year into days and months. But underneath, in small type, is the theoretical Earth date. Of course there'd have to be some fiddling; a planet with a twenty-three hour day would have more days, and the same Earth date would sometimes be printed twice. On a planet with a twenty-six hour day, two Earth dates might be printed for the same local day. This way there's no ambiguity.  Our youngsters can simply state their birthdays in the Earth calendar; the barman then glances at his local calendar and hands over two large Rudesheimer beers. They could, of course, be lying about their ages - but that's characterisation, not worldbuilding.

What remains is the flavour that holidays give to a civilisation. They can impart a sense of fun, like Christmas cheer and Easter bonnets. Or they can celebrate worthy things, such as getting the harvest in or the day the hydroelectric dam was opened. At worst they can be the birthdays of dictators or the anniversary of The Day We Enslaved The People In The Next Country. At best they can point to hopes and dreams.

Now it's up to you.  Decide if your world is alone, like ours, or part of a vibrant, colourful galactic culture. Choose the sorts of things your characters will celebrate,and that will tell us a lot about them. Find reasons for the origins of their festivals, and make up things worth commemorating. Look at the motivations of the people who create or promote events: do you have an ambitious young priest looking for reasons for more holy days because they'll bring offerings into the temple? Or a kindly old one who adds new celebrations to give the farmhands a few days off from back-breaking work?

Now build your world, and enjoy it.