measuring passage of time on a tide-locked world

[SMAndy85]

I'm creating a fantasy world, which is tide locked to its star. I've done some research on this, and I'm happy with my results, so that's not up for debate.

What is though, is how the inhabitants of said planet would mark the passage of time.

Key points;
the planet is tide locked. That means the same side faces the sun constantly. For the inhabitants, the sun barely moves in the sky.

There is a small wobbly in the orbit, which means the extremes closest to the hot side and cold side experience some seasonal fluctuation. Essentially the seasonal shift means the edges of the habitable ring shift between hottest/coldest every 4 "weeks".

A "year" is the equivalent of 8 weeks on Earth. i.e. the planet goes all the way around the sun and back to its starting point in 1,344 hours. This isn't particularly significant to anything, though.

There is a moon, which would be in the same point in the sky every 24 hours, giving an easy to mark work/rest cycle.

Medieval style technology, so it's feasible that they wouldn't even know the planet is going around the sun. Also, style-wise I'm going for old-english, so place names will fit to that effect. e.g. a town at the mouth of the river Bar* would likely be called Barmouth
*randomly chosen word, read nothing into this.

So. How would these people mark the passage of time? Names for these periods of time would also be a good thing to discuss. So far, my thoughts have been on the number of times the moon has passed them. I'm thinking it would be based on the number of times the moon passes, so ten-moon, or hundred-moon, perhaps. Let the discussion begin!

 

[KC Trae Becker]

There is a small wobbly in the orbit, which means the extremes closest to the hot side and cold side experience some seasonal fluctuation. Essentially the seasonal shift means the edges of the habitable ring shift between hottest/coldest every 4 "weeks".

A "year" is the equivalent of 8 weeks on Earth. i.e. the planet goes all the way around the sun and back to its starting point in 1,344 hours. This isn't particularly significant to anything, though.

Though the fluctuations would seem small to us, experience is relative and so the fluctuations would likely take on a greater value for them. So I imagine these differences of seasons and years would be noticed and used to mark time. rather than a random number count, especially if the technology and mindset(?) is more medieval.

 

[SMAndy85]

I can accept that. If that's all they see, that is all they would have to work with. If you accept an 80 year lifespan, which is 29,200 Earth days, that's 521 years for them.

You're right in that the mindset would be more medieval. I'm already toying with Stone Circles being used to accurately mark a year, and settlements having a form of moon-dial, on which you compare the position of the moon in the sky with markings on the dial/altar.

Thanks for the input!

 

[OfAllTheBars]

Would such a world not have developed an entirely different concept for time? Time for us is as it is because the earth rotates giving day and night, because its tilted on its axis giving seasons, and because we have a moon like we have that gives us tides (and many other reasons). Take away the rotation, the axis tilt, and the moon, and the concept of time could be entirely different. Having said all that, in your world the stars would still appear to move across the sky as the year progresses, so that would be a suitable measure of time and seasons - exactly as the appearance of constellations in the evening sky marked spring for ancient civilisations on earth.

 

[SMAndy85]

The problem there is for anyone in the habitable section of the world, there would be enough sunlight for the stars to be not visible. It doesn't make sense to travel up to a couple of thousand miles just to check what time of year it is by the stars. It is however feasible that one or two stars might be visible during the winter, but again, not for the parts of the civilisation closest to the hot edge. Those people would never experience anything like "night", during which the stars show.

However, you've given me an idea. Given there is a bit of wobble in the orbit, I would suggest that on clear days, the sun would cast a shadow that would move down a wall, allowing them to see how much of the summer was left. Different methods could be used in different parts of the world, allowing the stars to be a marker on the dark edge.

Thanks!