If the world was flat, what would the horizon look like?

The horizon curves away in the distance, and beyond that we can’t see anything, the world simply is no longer in our direct line of sight any further past that point.

But, barring atmospheric haze, what if the world really was flat - would we see more? Or would things peter out in size in mostly the same way that it does already so it wouldn’t be much different? (Obviously sunsets wouldn’t happen, either, but now I’m getting off my point)


“Well, roll me in eggs and flour and bake me for forty minutes!”

The Legend Of PigeonMan

I’m guessing that you’d be able to see farther,but not forever. Things would just get smaller.And why wouldn’t there be a sunrise? The sun would then go under the flat earth,and back around! Unless you think if the earth was flat,it would stretch out forever.

If the world was flat, I think the horizon would look a lot like Kansas

my WAG: It depends on how far you are above the surface. At low altitudes, it would be virtually identical to now. But at high altitudes, and in clear weather, I suppose you could see further, but things would get so small and out-of-focus that it still would not differ much from what you see now. You’d have to really be in orbit for it to make a real difference.

Why do I keep thinking it would look like a slighty upward curve?

You say “cheesy” like that’s a BAD thing.

Theoretically, your vision would eventually be blocked by distant mountain ranges. A person standing in Nebraska would be able to see the Rockies and the Appalachians on opposite horizons. Of course, at that distance they would only look like a miniscule gray line and atmospheric haze would probably make them impossible to see. You would probably also have a glowing haze on the horizon from the lights of distant cities.

Did anyone ever consider what it would look like to look off in the distance at the EDGE of the flat world? Would the sky still be blue, or would it be the black of outer space?

Visibility due to atmospheric haze and distortion rarely exceeds 20-30 miles in most places. Here in Southern Alberta we have some brisk winds that keep haze clear and very little atmospheric pollution, so we see visibilities of 70+ miles or so. That’s generally the farthest you’d be able to see.

Also, if you look at a topographical map you’ll see that unless you are situated on a high plateau there will usually be some small hills or rising terrain that will block your vision.

Looking out from the edge of a flat earth the sky would be black. Blue sky arises from sunlight scattering in the atmosphere. Where there is no atmosphere (I’m assuming the atmosphere stops at the edge of the earth) there could be no blue.

“The departure of the church-going element had induced a more humanitarian atmosphere.”
Dorothy L. Sayers
Clouds of Witness

Did anyone ever consider what it would look like to look off in the distance at the EDGE of the flat world? Would the sky still be blue, or would it be the black of outer space?

probably look like it does when you look up. a better question is what would it look like if you leaned over the side and tried to look under the world. and how thick would it be. are we talking theoretical 2 demisional.

The Earth is flat.


Thanks Nick. Now I’m going to spend all night wondering is the authors of that horrid prose went to school with Dr. Bronner.


“Listen Children Eternal Father Eternally One!” Exceptions? None!
-Doc Bronner


Speaking very mathematically, ignoring visiblity and terrain, the horizon would rise to eye level. That would be the perspective “vanishing point”. It seems that in a practical sense, it wouldn’t make much difference except when looking out over the ocean. When looking over the ocean, I would expect that the horizon would be higher and a lot fuzzier.

Well, to make a somewhat reasonably plausible what-if, lets just pick a radius of the earth that is much (say 10 to 100 times) the actual one. 10X = Saturn. 100X might make the sun wobble quite a bit, but I guess we’d still have similar “rising” and “setting” of the sun in re the earth. That might change people quite a bit, but at least they wouldn’t turn out with flat heads or something. :wink:

Anyhow, we’re told hereabouts in CA-US that we’re supposed to be able to see the top of Mt. Shasta from the top of the Mt. Diablo, 32.5 km east of Berkeley and almost 390 km due south of Shasta, and with nothing but the Sacramento Valley, and low hills at the far end, in between. I don’t think I ever made this observation, given the past and present problems here with air quality. Right now, you’re lucky if you can see Carquinez Straits from Diablo, about 18.5 km north of there. There are still fires raging in Yolo County, 129 km to the north. The sun has been very orange for over 1/2 a week in Berkeley, and there was only a half-light Sunday when I hiked in eastern Napa County.

However, let’s check out this claimed view, in theoretically transparent air:

Height of Mt. Diablo: 1.173 km
Latitude of same: 37.8 deg
Height of Mt. Shasta: 4.316 km
Latitude of same: 41.4
Difference in latitude (theta) then = 3.6 deg
The longitudes of the two differ only by a negligible 0.2 deg
Surface distance between the two: 390 km
Earth’s radius ®: 6717.2 km

The rise (roundness) of a segment of a circle or sphere, in this case, that between the two mountains, = R(1 - cos theta/2). This calculates to 3.3 km. If you figure the rise would cut off the view from one mountain to the other at a point halfway between, you then conclude that a line of view from Diablo, starting 3.3 - 1.2 = 1.1 km below this midpoint hump, would shoot a tangent of this hump that could see a mountain as low as 3.3 + 1.1 km above the midpoint impediment, or 4.4 km,. . .but Shasta is only 4.3 km high. OK, so the atmosphere would pro bably usually bend the image of the top of Shasta, by that much, into view. . .on the rare days, these days, that it is clear enough. Maybe, if the earth had a 10X diameter, and no cars or industry, we could see that poster up in Alberta from Mt. Diablo, but not exactly the whites of his eyes. . .but I think the Rockies would get in the way.

A post mentioned defocusing at larger distances. Of course, eyes that will focus 20 ft away will focus at infinity, but thermal air currents and inversions will distort distant images and raise them above the horizon (mirages), and and particulate matter in the air will disperse light to distort their color (purple hills).

Ray (Haven’t checked on this out with the Flat Earth Society.)

As Nanobyte mentions, the atmosphere, even if perfectly clear, would refract the light to effectively raise the horizon. Somebody who knows a lot more optics than I do could calculate how much.

The science fiction author Hal Clement mentioned the same effect in his novel Mission of Gravity, set on a Jupiter-sized planet that had lost most of its atmosphere. The natives believed that their world was bowl-shaped. (Sorry, Ray, for bringing fiction into it. :wink: )

Bob the Random Expert
“If we don’t have the answer, we’ll make one up.”


Refractions occur at media boundaries. What media boundaries would we be talking about here, since we are talking about light coming from the surface of the Earth to another object on the surface of the Earth?

Mirages are reflections, rather than refractions, and I would think that mirages would subjectively lower the horizon, because mirages reflect the sky, so at a great distance, the reflection of the sky would likely be indistinguishable from the sky itself.


That’s OK; people that read that stuff can’t help it. I think the Dude is looking for the reality truth though.


Between air at one temperature and air at another temperture – in the one case, what you see, say, in convection currents over a hot car roof – and in the other case vertically stacked layers of air.

I’m not really clear on the various senses of physical happenings in mirages, but it seems to me that “lowering the horizon” is equivalent, compound-imagewise, to raising what’s behind it. And if reflections are involved (as my dictionary says under ‘mirage’), it’s still a matter of vertical offset of images from in front of and behind the horizon, due to layers of air at different temperatures. Whatever the distance / planetary radius, the same interplay of sky and ground objects would occur.

Ray (The SD is only a mirage; nothing is really straight, but especially dope.)

Drive through Kansas, you’ll get an idea of what it would be like.

Suppose the earth was exactly like in the wall maps with the parallel longitudinal lines. It would have to be a cylinder. Could we still have gravity and all the normal phenomena. The arctic and antarctic would be harder to reach, though, at the ends of the earth-can.