# What if the world was flat?



## Fnord (Apr 20, 2012)

So I am more of a table-top gamer than a writer (though I write a fair amount of short stories that take place in the work-in-progress world I have designed).  In trying to fine-tune the _actual_ cosmology of the world (there's plenty of differing creation myths based on culture, but the theme of the game is finding the actual truth) it seemed to make sense, given all the other stuff involved, to attempt to make the world actually flat (or more accurately, a flat disc inside of a sphere not unlike the structure of a gyroscope).  

Now the players all assume the world is round.  I'm not looking at making it scientifically perfect in regards to things like gravity and seasons (it is fantasy after all), but what other subtle differences could I sprinkle about as clues (at least until the player-characters discover and dissect the ancient astrolabe puzzle thing that shows the total "unification" of the cosmos and gods) that the world isn't actually round?  What _are_ some scientific implications of such a place that I might toy with?


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## Devor (Apr 20, 2012)

Fnord said:


> What _are_ some scientific implications of such a place that I might toy with?



The horizon, for a start.  Objects in space and the sun rotating overhead in the sphere would move a lot differently.  I'm wondering if it would affect the climate and weather patterns in a way that's distinctive or not.  Tides would be based on the rotations of the plane instead of the moon.  I don't know if the characters would necessarily notice any of these.

The big question is what happens on the edge, and what's on the other side of the disk.  If there's a gap between the edge of the plane and the sphere, you might have things falling over the side - maybe rain is caused by water draining over the edge and whooshing around the sphere unsettled.  Maybe there's no gap, and you can walk to the edge and touch the moving walls.  You need to figure out some of the implications to those possibilities.


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## SeverinR (Apr 20, 2012)

We had a post that included something like this recently but couldn't find it.
One problem with a flat world...Does the sun set? Or is it day all the time? Does it tumble end over end, so there is a day and night? Slow tumble could make day period longer then earths.
They offered a flat spin rotation idea, but that doesn't really fix the day/night thing. It could make for a bright/warm time(closest to the sun)and a cool dimmer time.(away from sun)
How does weather move around?
How does the inhabitants differ on a flat planet compared to a round spinning one?
I believe a flat home planet can work, but some basic reasons need to available, so even if not specified, you can describe it correctly with a reason in mind.


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## grahamguitarman (Apr 20, 2012)

Actually the horizon would not look any different till you got closer to the edge of the world.  I know this because I spent two years studying the science of perspective in minute detail.  Until the edge comes within viewing distance it would initially be at the same height within the field of vision - eye level.  Because of the geometry of vision, the horizon is always at eye level (a simple way to test this is to look out to the sea and then crouch, as you crouch the horizon level will drop with you).  

So to begin with the Horizon will be where it usually is on a round world.  But as you get within viewing distance of the edge, the horizon would seem to get lower within the field of vision.  The visible horizon will continue to get gradually lower in the field of vision, until it becomes visually obvious that there is a drop beyond the edge of the world.  

If there was a mountain range at the edge of the world though, you would not even see the horizon so this visual effect would not be seen.


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## Devor (Apr 20, 2012)

I thought there were issues of objects moving on the horizon? I thoughtful I remember something about Columbus watching boats tilting downward as they vanished at sea.  I was vague, though, because I wasn't sure the impact.


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## Fnord (Apr 20, 2012)

Devor said:


> The horizon, for a start.  Objects in space and the sun rotating overhead in the sphere would move a lot differently.  I'm wondering if it would affect the climate and weather patterns in a way that's distinctive or not.  Tides would be based on the rotations of the plane instead of the moon.  I don't know if the characters would necessarily notice any of these.
> 
> The big question is what happens on the edge, and what's on the other side of the disk.  If there's a gap between the edge of the plane and the sphere, you might have things falling over the side - maybe rain is caused by water draining over the edge and whooshing around the sphere unsettled.  Maybe there's no gap, and you can walk to the edge and touch the moving walls.  You need to figure out some of the implications to those possibilities.



The horizon was the first thing I thought about and I had trouble visualizing how that would look.  The world was battered by a cataclysm/reckoning/insert-your-own-trope-here about a millennium ago and thus it is very "young mountainous", especially where the characters are, so the horizon isn't all that obvious anyway. But they will soon ascend to the top of the tallest mountain and it may be more apparent.  i remember standing at the top of Scottsbluff in Western Nebraska and _really_ being able to see the curve of the earth.  It was pretty crazy.  It's hard to picture in my head seeing even _further_.


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## Fnord (Apr 20, 2012)

grahamguitarman said:


> Actually the horizon would not look any different till you got closer to the edge of the world.  I know this because I spent two years studying the science of perspective in minute detail.  Until the edge comes within viewing distance it would initially be at the same height within the field of vision - eye level.  Because of the geometry of vision, the horizon is always at eye level (a simple way to test this is to look out to the sea and then crouch, as you crouch the horizon level will drop with you).
> 
> So to begin with the Horizon will be where it usually is on a round world.  But as you get within viewing distance of the edge, the horizon would seem to get lower within the field of vision.  The visible horizon will continue to get gradually lower in the field of vision, until it becomes visually obvious that there is a drop beyond the edge of the world.
> 
> If there was a mountain range at the edge of the world though, you would not even see the horizon so this visual effect would not be seen.



Awesome, I typed my response before I saw this.  Thanks, that's one of things I was curious about.

As to the edge, it's kind of hard to explain--as you approach any of the edges of the terrestrial world you actually get closer to one of the four "land-level" elder gods realms.  The best way to visualize it would be a five-circle Venn diagram, with the "mortal world" in the center.  So approaching the "edge" just eventually takes you into a realm that more reflects of the "domain" of the god in that given direction.  So there isn't an edge, per se, in that you could approach and look over it.  It's more of a boundary.

There is definitely an underside, a hellish realm that is in every way an "underworld".  It was actually the first mortal realm, though I'm still fleshing that part of it out.


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## Queshire (Apr 20, 2012)

If there's no edge, then would it matter or not if it was flat?


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## Steerpike (Apr 20, 2012)

How thick is it? In other words, is there enough mass to retain an atmosphere and have the right gravity for the lifeforms on the surface?


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## Queshire (Apr 20, 2012)

Er... If the world's flat to begin with I don't think scientific stuff such as gravity and atmosphere are a concern...


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## Legendary Sidekick (Apr 20, 2012)

If you fall off flat Earth...

The end of space is ten feet below the edge of the world. Only a basketball player can jump, grab the edge and hoist himself up.

When you fall off the edge, you land safely on the black cushion of space to find that the world is actually a giant caterpillar's back.

When you fall off the edge, you fall back up, find yourself doing a headstand, and tip over. You are now on the "tails" side of the coin-shaped world. The bottom isn't much different from the top, except that plants grow root-side-up. As a result, carrots and potatoes are more popular than apples and oranges.


Those were the first three what-ifs that popped into my head.

Regarding alternatives to the real round world, there's the traditional flat world that is also the only world and the center of the universe. There's the inverted round world, which I remember reading in an ancient myth. It's like the Game of Thrones map you see in the HBO series, with the sun moving around to bring daylight. Other possibilities: stars are not suns, like in Stardust--they're immortal women. You could have portals at the four corners of the world, like those shortcuts in the board game Clue which take you to the opposite corner of the board. Then you've got that Men in Black thing where a Universe exists inside a marble, which can be held in the hand of someone from another Universe.

I'd bet a nickel that most fantasy readers can accept just about any alternative explanation of the world, except...


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## Devor (Apr 20, 2012)

Legendary Sidekick said:


> I'd bet a nickel that most fantasy readers can accept just about any alternative explanation of the world, except...



I feel compelled now to create a story on Earth as a box.  Possibly centered around a giant groundhog.  Named Jack.


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## Steerpike (Apr 20, 2012)

Queshire said:


> Er... If the world's flat to begin with I don't think scientific stuff such as gravity and atmosphere are a concern...



You may not have noticed, but everything in this thread relates to scientific issues in some respect. The OP said he didn't want to make it scientifically perfect, but didn't say he did not want to consider the issues at all. Thanks for the insightful commentary, though.


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## Steerpike (Apr 20, 2012)

Devor said:


> I feel compelled now to create a story on Earth as a box.  Possibly centered around a giant groundhog.  Named Jack.



Does he pop out at certain times?


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## Fnord (Apr 20, 2012)

It's definitely more of the "nickel" way of looking at it.  Should one delve deep enough into the ground, eventually gravity reorients itself and you're climbing back "up" toward the underworld.  

It being flat is more of a way to mess with the anachronistic assumptions of the players and to make the setting a truly fantasy setting rather than just being a "round-world with fantasy elements" sort of thing.  And given all the other aspects of the cosmology, it ties together very nicely.  Pondering some of the less-obvious scientific implications is helpful in allowing me to decide what to keep and what to scrap.  An atmosphere is a good question, for example, because I didn't really consider if one exists.  It's probably not a question that necessarily needs to be answered (space travel is not possible in an Iron-Age-esque setting) but there are other implications: for example I do make the air get thinner at extreme heights (which is useful for making it challenging for characters who are playing primarily in a mountain-heavy setting) so there obviously must be _some_ sort of atmosphere.  Does that necessarily need to be fleshed out in a factual matter?  Not necessarily, but it definitely bears thinking about (on the topic, going _up_ also goes to a godly domain, so the Venn diagram I mentioned earlier is actually three-dimensional).  

The giant caterpillar comment made me laugh.  "It's turtles all the way down. . . ."


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## Legendary Sidekick (Apr 20, 2012)

February 2nd, or when the music stops after Ty Tongul, the God Who Strikes Planets Into Black Holes With His Pool Cue Because He Can, cranks Saturn's ring several times.


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## Queshire (Apr 20, 2012)

Hmm~~~ I suppose technically you're right in the sense that science is the study of natural laws, but the thing is that his world, by neccessity, does not have the same natural laws as our world and so there's a limit to the usefullness of comparing the two. Quite frankly, there might not be a reason for why something is what it is, or if so it could be as simple as a god deciding it to be that way for the lulz.

Anyways, back to the original question, I'm not sure if my mental model of this world is accurate, but one possible hint might be the sun and moon visibly shrinking and growing during the course of the night/day when you're closer to the rim due to it actually getting closer/farther to you as they go around the flat world.


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## Fnord (Apr 21, 2012)

Queshire said:


> Hmm~~~ I suppose technically you're right in the sense that science is the study of natural laws, but the thing is that his world, by neccessity, does not have the same natural laws as our world and so there's a limit to the usefullness of comparing the two. Quite frankly, there might not be a reason for why something is what it is, or if so it could be as simple as a god deciding it to be that way for the lulz.
> 
> Anyways, back to the original question, I'm not sure if my mental model of this world is accurate, but one possible hint might be the sun and moon visibly shrinking and growing during the course of the night/day when you're closer to the rim due to it actually getting closer/farther to you as they go around the flat world.



Yeah, to me it's mostly about some degree of internal consistency, at least in that it makes some sense.  The sun/moon aspects are kind of a hurdle, for example.  In our worlds, the seasons are determined by the axial tilt.  But a flat disc doesn't really have a tilt and if it does, the effects of that tilt are a lot more extreme.  Moreover, it most definitely has to be a geocentric setup, as opposed to a heliocentric one.  So _how_ the sun moves in relation to the world itself is important.  I've tried to envision in my head that if the world is essentially a unit circle, with the center of the disc being the origin, then the sun would move in a wide parabolic arc from the south (bottom) of the disc which would then drift further and further away from the origin as the seasons move from summer to winter and move closer to the origin from winter to summer.  Thus the summer solstice would be when the arc came closest to the origin and the winter solstice when it was furthest away from the origin.  

Now the moon on the other hand. . . .


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## Queshire (Apr 21, 2012)

you use big words! XD Fun fact: The seasons on our Earth aren't related to how close the earth is to the sun, and in fact the earth is closest to the sun in the middle of winter, some time in Janurary I think. 

Again, your world isn't our world, you should't feel limited to our natural laws, don't think the seasons have to be connected to the sun, just like in greek myth, in your world winter could simply be the result of the nature goddess feeling sad. Don't be afraid to just say a Wizard (or perhaps a God) did it and leave it at that. In fact, a good way to portray the... else-ness of your world would be have the characters try some scientific experiment and have it more or less fail.


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## Fnord (Apr 21, 2012)

Queshire said:


> you use big words! XD Fun fact: The seasons on our Earth aren't related to how close the earth is to the sun, and in fact the earth is closest to the sun in the middle of winter, some time in Janurary I think.
> 
> Again, your world isn't our world, you should't feel limited to our natural laws, don't think the seasons have to be connected to the sun, just like in greek myth, in your world winter could simply be the result of the nature goddess feeling sad. Don't be afraid to just say a Wizard (or perhaps a God) did it and leave it at that. In fact, a good way to portray the... else-ness of your world would be have the characters try some scientific experiment and have it more or less fail.



Right, it's not the proximity, but the duration the sun shines on a given hemisphere which on a round planet comes from the wobble of the axial tilt.  Trying to replicate that with a geocentric flat plane would mean the "sun" in this given world, would have to move itself in some way so as to shorten the days.  The "southern" part of the disc wouldn't see much change in seasons (much like our equator) because even if the sun's path receded from the center of the disc, the southern part of that disc (or the third and fourth quadrants if we keep with the trigonometric descriptions) would still have plenty of sun exposure.  

Of course, now that I think about it, the sun's path would still have to come up at some sort of angle over the disc to replicate the axial wobble.  But then that introduces some other implications, haha.  

In my head, the "sun" god is merely whipping a flail over his head in an arc with the "sun" being the fiery ball at the end of his flail.  When the arc of the flail moves away from the world, the northern god ("the Cowled One") moves in and blankets the world under his dark cloak.  Of course I don't have to be so mathematically precise, but being a mathy guy it helps me visualize how the physical differences work out.


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## Ivan (Apr 21, 2012)

I am reminded of "Flatland" where there is a pronounced horizontal gravitation which gets stronger and stronger depending on the region. Since someone on the edge of the world would have the entire earth to one side, they would feel a pull in that direction; someone in the center would only be pulled downward. You could decide just how strong this pull is, from making it impossible to reach the edge to being just a small but noticeable force. This would be easy to implement and a fairly clear hint as to the shape of the world, as opposed to any bizarre astronomic effects.


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## Steerpike (Apr 21, 2012)

Ivan said:


> I am reminded of "Flatland" where there is a pronounced horizontal gravitation which gets stronger and stronger depending on the region. Since someone on the edge of the world would have the entire earth to one side, they would feel a pull in that direction; someone in the center would only be pulled downward. You could decide just how strong this pull is, from making it impossible to reach the edge to being just a small but noticeable force. This would be easy to implement and a fairly clear hint as to the shape of the world, as opposed to any bizarre astronomic effects.



That's pretty cool. I like the idea of not being able to reach the edge because of this.


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## Ravana (Apr 21, 2012)

I've used the opposite of this to set up a specific effect I desired–I _wanted_ people to be able to "fall off the edge." In this world, gravity is polarized, rather than being a function of the center of mass. Thus, the force of gravity is the same all across the surface of the world… _until_ you get to the edge; once you get there, it's _reversed_. 

Which, of course, is how it's possible for ships to sail to the homes of the gods (i.e. the "stars"). Well, that, plus "space" not being a vacuum. 

Note that while this makes it fairly straightforward to leave the surface of the planet, _returning_ can be problematic.… 

-

[Note also that this is an example of my frequent reminder: "With gods, all things are possible." That's the way they wanted the world to be, so that's how it works.]


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## Androxine Vortex (Jul 2, 2012)

Sorry to resurrect an old thread (Threadomancy!) But I am working on a project that too has a flat world. I really don't have to go too into detail about the why's and how's because the world-disc was created by the Gods and if they say it will work then who are we to argue? So let me draw you a mental imagine of my world...

There is the Earth and it is a flat disc. Now imagine a huge dome that got placed over it. That would be the horizon. So even though the Earth is flat, the horizon and sky is still in a curved, half-spherical state. How would that affect people's perception of the sky?


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## Benjamin Clayborne (Jul 2, 2012)

Androxine Vortex said:


> Sorry to resurrect an old thread (Threadomancy!) But I am working on a project that too has a flat world. I really don't have to go too into detail about the why's and how's because the world-disc was created by the Gods and if they say it will work then who are we to argue? So let me draw you a mental imagine of my world...
> 
> There is the Earth and it is a flat disc. Now imagine a huge dome that got placed over it. That would be the horizon. So even though the Earth is flat, the horizon and sky is still in a curved, half-spherical state. How would that affect people's perception of the sky?



Depends on how big it is. If you're near the edge, it might be more obvious that there's a dome in play. If you're closer to the middle, it would just look like sky the same way we see it now.

Or you can ignore the trigonometry of it and have it look however you want, because, you know, magic.


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## ShortHair (Jul 2, 2012)

One explanation for a flat earth is if reality is consensual, that is, the universe behaves the way most of the people expect it to behave. You can "prove" that the world is round, as Archimedes did, but he was outvoted and the world stayed flat. If you can only explain the motion of the planets with a set of crystal spheres, then the solar system is a set of crystal spheres.


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