Measuring Time in a World Where the Sun Never Sets

Question

First time here, so I don't know what to expect.

I'm writing a dark sci fi mystery story that takes place on a hypothetical megastructure called an "Alderson Disk" (Example seen Below). Humanity on the disk has sorta fallen into a dark age, reverting back to feudal ways. So I was wondering, how would a civilization keep track of the passage of time in a world where the sun would never set, there are no seasons, and they don't possess the technology to build anything to keep track of time and how might it affect their language and culture?

I can't think of anything that would help, aside from removing the concept of "time" from their languages and cultures altogether. Any ideas would be greatly appreciated!

Answer 1

I have to reject your premise. IRL, Primitive hunter-gatherers used tied-off animal bladders as canteens to carry water with them. Hang a bladder from a tree with a pinhole in it; let water drip into some other vessel (e.g. a depression lined with a bladder), and the volume of water collected measures time.

People would have to be animals to not be able to measure time.

As others have mentioned, sleep is a necessity for the brain, and not just for "rest". A primary biological function of sleep is for the body to conduct janitorial work on the brain; neural functioning consumes energy and eliminates waste. Neurons are living beings, after all. If this waste accumulates, it can literally kill neurons, it impedes their oxygen uptake and creates pressures on them that choke them to death.

During sleep, blood vessels dilate and put pressure on the neurons, which can make them malfunction, but more importantly, the pressure causes them to expel their waste into the bloodstream, to be transported to various waste receptacles in the body. Being unconscious during this cleaning process protects the person by preventing action based on these neurons misfiring during cleaning (which they do). There are other important functions that are performed during sleep as well, such as memory consolidation and learning, that also physically affect neurons.

As a general rule, it is best to turn the machine off when you are changing the parts of the machine.

The closest analog I can think of for your purpose is dolphins; they have a survival need to be alert 24/7. So they have evolved a mechanism in which the lobes of their brain take turns sleeping for this janitorial and updating duty. When one lobe is sleeping for several hours, the other lobe handles the alert duties; swimming and staying with their companion dolphins, on the lookout for predators or food, and ready to wake its partner lobe in any emergency.

Dogs are another time-keeping species that can "smell" time. Even entirely during daylight, a dog's sense of smell can tell how old a smell is. For example, when their owner leaves the house, the dog can detect their owner's scent decaying. So accurately, that if the owner always leaves for the same amount of time every day (like going to work for 8 hours and coming home), the dog can reliably anticipate their owner's return within about 15 minutes, and come to wait for them at the door. That scent-decay is the key here has been proven in experiments, by artificially changing the scent concentration and thus fooling the dog.

So there is a biological route that has nothing to do with day/night cycles. Both dogs and dolphins also have some sort of time-keeping that is based on sleep cycles or days. Treated well and as friends, both species "fall in love" with their keepers, and an absence of days can cause mourning behaviors in the animal. While a return of their keeper can cause rejoicing behavior; we have tons of returning-soldier videos where their dogs just go nuts with joy greeting their return. Dolphin keepers can also form relationships with dolphins, playing with them, and the dolphins react similarly when their friend disappears (on vacation or leave for some reason) and then returns weeks later. The dolphins engage in excited greeting and play behavior.

Neither of those is possible without some internal sense of "long" times; and for animals that sleep in several sessions throughout the day (or in the case of dolphins are never fully asleep) it seems some other long-time mechanism must be in play, in their brains.

In any case, for primitive hunters, bladders and stomachs were ready vessels for carrying wet or liquid products. It is suspected that cheese was accidentally discovered by carrying goat's milk in a stomach tied off to work like a canteen; it fermented in there. And a water clock can be made from them without any advanced technology.

Answer 2

Presuming the platter turns, I think that if you look outward, away from the sun, you would see the stars, which would drift by over the course of a year (one turn of the platter). You could mark local time by which constellation was directly radially opposite the sun.

All the shadows in this perpetual sunset world would be pointing at a particular constellation on the celestial equator corresponding to the time of year. "Oh look, it's Orion o'clock!"

Answer 3

The sun doesn't have to set to produce regular noticeable cycles.

Just have it bob up and down through the central hole in the disk.

Sometimes, more of the sun will be visible, and the world will be slightly brighter. Other times, less of the sun will be visible, and the world be slightly dimmer. And those changes will occur perfectly regularly, just like the regularity of day and night on a spinning spherical world.

Answer 4

An object falling from a known height will always take the same amount of time to reach the ground. They can count drops or bounces of stones or something else.

They can also count blinks, or breaths. You might think these are inexact and different people will have different measures. It was just this way in primitive societies. To this day, where I come from, there is a measure of time which goes like "I'm gonna spit on the ground and you have until it dries to be back or else". Ancient chinese would burn rope to measure time and the ancient greek measured the time it took for a container with a hole to spill all of its water.

Answer 5

It is a bit of a design change but an artificial light/heat system along both sides of the disk provided by energy collected by a Dyson swarm/sphere around the star could regulate day-night cycles.

Other than the instability of an Alderson disks structure, which would likely collapse into a sphere, receiving enough light across the whole disk is an issue that could be solved with artificial lighting.

Similar to an enclosed cylinder habitat which needs a light and heat source, the designs for an Aldersons disk could vary, something simple like street lights kilometres high above the disk could work but other more elaborate/functional designs would be interesting to think about.

This means the outer edge of the disk does not need to have very low temperatures, although it could still be, for housing computers to run more efficiently at the cold temperature. The star in the middle of the disk is only surrounded at the equator by the wall area that is needed to hold in the atmosphere, the rest of the star could then have a Dyson swarm or sphere to harvest enough energy to power the artificial light, which could then be used to regulate day-night cycles for both sides of the disk.

Answer 6

We base our time around the rotation of the Earth and it's orbit around the sun, but your world may not have any suitable markers.

First you have to ask why you're keeping track of time in the first place. Until something is due to happen at a specified point in the future, time is utterly unimportant.

The hunt goes out, the hunt comes back. The quarry is cooked until it's ready, the children play until they're called back. You sleep when you're tired and get up when you wake. None of this requires time.

No days or nights, no seasons, you don't need a farming calendar. No winter to stock up for, no spring lambing to prepare for. Merchants arrive and set up stalls when they do. When you want to sell goods, you take them to town and sell them. Market days are a nice idea, but not required.

Time gets more interesting when you start wanting people to pay taxes regularly, but that wasn't a thing for most of history. You can just tax the merchants against value of goods as they pass through town.

Finally you get to the industrial age and railways. Time suddenly matters, what time does the train come, what time does it go. What time did you get to work, what time do you leave. Travel and factory work require time and for your world that's the first time it will be important.

Until then, things simply happen, one after another.

While we as an "advanced" civilisation have all sorts of ways of considering time and its importance, before you project that onto your world, you have to come back to that first question. Why?

Answer 7

Living things still need to sleep at some point, so there would still be some sort of way to measure time, but it would likely be based on your personal need to rest.

One way to still have a basic concept of days/time would be based on jobs and the necessity for structure, where the "boss" would likely have a set time that the "employees" would be given opportunity to sleep or do anything else. Presumably this would be based around the "boss" needing to sleep and forcing everyone else to function around their needs, as you mentioned these people do not have technology to measure time in any capacity. This could extend out further to a civilization by replacing "boss" with "ruler" and "employee" with "subject".

Basically, someone in power decides when others get to sleep based on their need to sleep, and a new "day" is started when they wake up.

Answer 8

They track the years.

https://www.english-heritage.org.uk/visit/places/stonehenge/things-to-do/solstice/what-is-the-winter-solstice/

There is a structure on the disk, near where the story takes place. Now it is a built thing but underneath the standing stones are artifacts left by the ancients who built the disk.

The disk turns. One rotation around the star is a year. The sun tracks a slow path along the edge of the sky. On one day in the year, the sun aligns with the structure in a recognizable way. The sun shines through the Eye Of Klive on that day and if you know how to look the long shadows form the shape of Klive's Hand.

That day marks a year. The passing of another year is celebrated at the structure with a ritual marking and sacrifice underneath it. The many years that have been passed can be seen in these sacred marks.

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Or it was celebrated. I picture a dark age where the people no longer come to the structure. There is no-one to come. An old woman lives nearby with the child she has rescued. She marks the time herself. The old marks are beautiful. Her new marks get the job done. Sometimes the child adds to the new marks, to make them a little more beautiful so they are not ashamed.

There are similar structures elsewhere on this world. There the people have all gone and there time has stopped. If you understand the marks, you can tell when the last ones were made.

Answer 9

Your main problem is the disk doesn't make sense, and making it make sense probably makes time easy to measure.

I know there's a Wikipedia article. That doesn't explain how a disk in which gravity is "down" toward the Sun, as they describe, has atmosphere on the habitable area. Now to be sure, you could rotate it (make a Ringworld out of it) but then the air near the Sun falls down and the air further out flies away and there's still no atmosphere.

You could make it an honest-to-God ring system (like Saturn's) with different orbital speeds as you change radius (faster the closer you are to the Sun), and enough gravity on the disk to hold the air near it (plus, any other orbit for a gas particle intersects the disk again). But then you'll have frequent joints between different circles of the disk, and the natives can have a (very lengthy) Book of the Passing Landmarks they use to measure the exact time within each day, or at least measure the displacement of distant landmarks to keep rough track.

Note that it is still essentially a poorly-designed Ringworld, and unstable - the nearest part of the ring to the Sun will pull the Sun nearer to it still. You'll need some corrective measure, such as attitude jets, and the firing of each jet as it revolves past the Sun will provide a regular timepoint for a clock system. The fading of the exhaust gas might be used to estimate hours within the day.

Answer 10

If these people are really people, say descendants of Stross-esque nuclear holocaust blown back to hunters-gatherers and losing all concept of our civilization, then there is not one natural, but two natural cycles - one is the sleep cycle (that might be not uniform across people and will likely drift towards longer "days"), and the second one is the menstrual cycle, and this will probably play a major role in creating time reconing system once they start building cities and bureaucracy. Divided by 20 or 24 (depending on how much the average sleep cyclle takes) will give them *days and once their science progresses, they will divide the days by 12, 24 or whatever their number base system.

Answer 11

I'm assuming these people have agriculture, so they will at least have units of time based on growth of their crops - how long that is will depend on what they grow and the climate in the area they're in. For more precise time measurement they could use something like an hourglass.

Answer 12

Huge gravity means satellites: moons, other planets, dust clouds, etc. so already you have very obvious candidates even with primitive technology. Gravity is an excellent clock as pointed out in (most) answers. Heat transfer is another obvious candidate - take ice from the frozen zone, thaw it in the habitable zone. And, of course, life. We already measure this - generations. My family has been here for 10 generations, i.e. approximately 600 Earth years for a human, a lot shorter for a mouse on mars.