Yhyjyk

Assume a planet that always presents one side to the sun. No moons. The orbit of the planet around the star is essentially spherical, very minor and undetectable aberrations. The orbital period of the planet around the star is in multiples of the lifetimes of the sentient beings. That is, no sentient being lives long enough to go through one complete rotation.

NOTE: this question is not about HOW this would happen, it is to be taken as a given that it DID happen.

A sentient species evolves on this planet.

There are no day/night cycles, no seasons, and no cyclical changes in the sky - it would be constantly different throughout one's lifespan. No repeats. Life evolved without any natural circadian rhythm. Plants grew and died independently of any cycle. No defined growing season. A plant could sprout at any time, and die at any time. No menstrual cycles, no estrus cycles in animals. There would be no biological basis on which to establish any. Life would have evolved without any concept of cyclical time passage. As far as life was concerned, everything was eternally homogenous, time wise. Nothing happened in unison.

To these sentient beings, the passage of time is irrelevant. They have no way to compare the passage of time between people. Heart beats are different, respiration is different, one's pace in walking is different. The interval to travel from one point to another is different. It is human experience that what seems like a long period of time to one person is a short period of time for another person. The beings get to where they are going when they get there, without reference to anyone else's travels. They eat when they need to, irrespective of how long it has taken between meals (think of a snake, that can go for very long periods between meals, depending on how big the last meal was). Gestations are never the same length, so even if two beings got pregnant at the same time, the deliveries would never likely be at the same time. Two objects released from a height at the same moment would be observed to arrive at the ground at the same moment, but there would be no indication that if dropped at some other moment they would arrive at the ground in the same time as these two, without some form of quantized time.

Many of our 'Laws of Physics' require time to be quantized. Humans, of course, had to quantize time before we could develop any theories based on the quantization of time. This is a straightforward 'chicken or egg' thing.

It seems to me that if Galileo had no preconceived idea of the measure of the passage of time (through the passage of seasons, day/night cycles, etc) he would not have been able to discover that the periodicity of a pendulum was constant. Depending on his state of mind, sometimes the swing would appear to take forever, sometimes it would appear to be shorter.

It also seems to me that Newton relied on a distinct concept of the passage of quantized time before hand, in order to develop many of his Laws. (The action/reaction thing, and gravitational attraction thing, would be valid, just not quantized as to the passage of time).

Building structural integrity and engineering calculations for stresses have no time component to them, if built by 'Rule of Thumb' (We built the last one this thick, and it is still standing. The other one was built thinner, and it collapsed.)

If this sentient species had no experience that the passage of time was measurable and periodic, would they ever develop a method to quantize it? Would they ever TRY to quantize it, if there was nothing in their environment that was consistently and repeatedly cyclic, that they needed to or even that they could consistently measure? What would that quantization look like?

I submit that this question is NOT the same as this, as many of the answers pertain to some form of naturally occurring cycle observable by humans, and /or are based on human circadian rhythms, which are not experienced by this species. This life form evolved without any ability to determine periodic time spans. Also, that question asks what would they use to quantize time, this asks what would their method of quantizing time look like? Would they even understand that time could be quantized into absolute divisions, that were equivalent between people and between events?

A further corollary question will be something along the lines of 'What would the Laws of Physics look like without time being quantized in the same constant periodic way that humans have quantized it?' But that is NOT in the scope of this question.

Just because the heavens don't tick doesn't mean Earthly stuff won't tick as well.

People are going to count their heart beats, breaths and bowel movements.

Humanity may have used the sky as its sole time piece for millenia, but once we started to pay people by the hour we got creative. The sundial was the last time piece to depend on astronomy. The chinese would count time by seeing how long standardized ropes would take to burn. On this side of the world people would use hourglasses and water clocks. Sand and water take a fixed amount of time to clear a reservoir of a fixed size with a hole at the bottom.

Your people may not have the concept of a day, but they will still have some measure which they can use to make the life of office workers miserable. "How dare you say that the new feature for our app isn't ready yet, Rob? You told us it would take three turns of the hourglass during last scrum meeting!"

I am going to assume that your creatures have a social system. I'm also going to call them humans sense that's easier to say.

There are a lot of different reasons why social systems form, but sense your people are capable of language I am going to assume that it was for trade and to cooperate in hunting, both of which have TIGHT connections to time.

How much do you pay the Sheppard for watching your livestock? By the hour.
How long do you cook bread for? How long do you wait before reaping your fields? When someone says they'll send a shipment to you, how long do you wait before you tell them they're late and in breach of contract?

If your people don't care about answering these questions, they're not intelligent enough to form an understanding of time even in a world with cycles.

Would they create concept of time, or especially effective way of measuring it a bit later? Possible. Would it be so shocking for them? No. Reason? Biology. We can't escape it.

• heart beat (escape that)


• circadian rhythm


• menstrual period


• pregnancy length (escape that, also for all major species)


• reproduction seasons of other species (in case of many species there is clear edge in doing it in one big go to overwhelm predators or find mate, example cicadas that perfectly aim their mating season every 13-17 years, yes prime number to make predators live harder)


• time necessary for their crops to mature from seedlings

EDIT: Clarification
How would animals manage? Not sure. Solar (spot) cycles? Star location on twilight zone for migratory animals? There is NO natural cycle taking 13 or 17 years, but because of evolutionary pressure animals managed to get it right. I would consider as highly unlikely if no animal managed anything like that.

Plants do NOT have to be synchronised, even on Earth. However, there are plenty of short lived plants, that have a few months cycle from seed to crops that are harvested. It does not have to be related to any special cycles like seasons. On Earth, in very good climate rice can be harvested 3 times per year.

If they are civilised, they are likely to have agriculture. If they have agriculture, then yield they should have some staple crops, with a few specially productive dominating. Sooner or later they start some big scale monocroping. Whatever is the time it takes from them to produce edible seeds, that period is roughly constant for any specific breed.

If economies of scale still apply here, then they will create growth and harvest cycles by selection (a la Gregor Mendel), tuned to the crop and location, once populations become efficient enough or large enough.

This is sufficient to create a kind of local calendar, quantized into arbitrary units of equal length (it's five units until harvest... time to prepare!). And I suggest those calendars will be based not just on selection-based growth cycles, but also on the level of effort of planting, tending, harvesting, etc by these sophonts. Again, economy of scale.

If they are thoughtful, their calendar will be easily divisible for those lacking mechanical calculators: 12 units, or 60 units, perhaps. They won't be base-ten.

If other crops become aligned, a less finely-tuned calendar could emerge, born from the interactions of multiple cycle times. Or one could win primacy, and the others would have correlations, and calendrics could become a career or an avocation.

These units could then form the basis of a clock: again, economies of scale imply that they will eventually have a schedule and meetings and therefore need to synchronize on an external standard. If units are quite large, then one turn of the clock could be one unit. Otherwise the clock equals the calendar.

And thus they, too, could arrive at modern conceptions of time.

You'll have to remove economies of scale to remove the calendar, and by implication the clock.

If they were a hierarchical species, it's likely that time would be measured relative to the length of a founder-equivalent reign. This is how time was traditionally marked in monarchical societies. I'd guess that the most likely to evolve subunit would be either a base related to digits/appendage count (base ten for humans, base 8 for an arachnid species) or based on subunits of 60 - which is divisible by 1,2,3,4,5 & 6 and a natural subunit.

Biological rhythms might be irregular, but chemistry remains the same.

Chemical reactions aren't based on solar cycles, and they're the same everywhere in the universe. As soon as your species starts doing chemistry they're going to need to measure time, and also will have a means to do so.

And what's the granddaddy of all chemical reactions? Fire. As soon as one of your creatures tries to search a cave using a torch or cook an egg, they'll start to figure out this "time" thing.

Even in a tidally locked world has a changing sky.

The world you describe has a constant sun and no moon, but it still has stars. And those stars will change as the planet orbits through the year. When your creatures venture onto the dark side of your world, they will discover the yearly cycle that can't be measured by the non-existant seasons.