In this thread, Meltdown posted a link to the Wikipedia page for the Flat Earth Society, which gave me some entertaining reading.
But it also got me thinking. What if the Earth actually were a flat disk as described by these folks? What would it look like from here on the ground? Would there even be a horizon? Could I see the Rocky Mountains, 1000 miles from here? Any chance I could pick out the Manhattan skyline from the top of the Sears Tower, 800 miles away? Could I see the entire world from the peak of Mt Everest? That would be cool.
I’m not sure what you think we’d have instead. If you look up, you see sky. If you look down, you see ground. At some point in between, you see one give way to the other. That point is the horizon.
I’ve given this some thought, actually, as a story I used to post about was largely set on a flat Earth. One thing that occurred to me was that there should not be any situation in which storm clouds seem to cover the entire sky, since the entire world was not having the same weather at the same time.
Rather than the horizon, I think what we would see is something like what we see when we look out into space–say towards Luna. A continual getting smaller, rather than a illusory meeting of sky and ground.
Ooops – duh, of course. I’m just having trouble visualizing what that horizon would look like, without most of the world dropping below my line of sight at any point.
It would look virtually identical to the way it does now. As Chronos says, you’d look up and see sky. You’d look down and see ground. The difference would be that instead of seeing sky down to 90.01 degrees below the zenith, you’d see it down to 90.00 degrees instead. Big whoop.
Not without a powerful telescope and absolutely no intervening obstructions, and no haze or fog or pollution between here and there.
Nitpick: Both on a spherical earth and a flat earth the horizon would be exactly 90 degrees if you had zero height and below 90 degrees if you had any height at all. It would be at a larger angle though for a spherical earth and any non-zero height.
Sorry saved wrong quote attribution. That’s Freddy the pig.
ETA: I see this thread is not discussing ways to (un)show that the Earth is not flat, but to speculate on the ramifications of a world that was, indeed, flat.
Well, first off, what happens to the oceans? Wouldn’t there need to be a giant sea wall engirdling the Earth? Like the city/world of Dark City?
I believe the horizon on a flat planet would be at infinity. Of course haze and such would limit the distance you could see but on a spherical planet the horizon is where the earth curves “down” and out of sight for you. About 3 miles for an average sized human.
That limit would not exist on a flat planet.
I presume this would be visually notable compared to standing on the earth.
No, on a flat earth, assuming you could see arbitrarily far, the horizon would be at 90 degrees no matter how high you were. At any angle below 90 degrees your line of sight will intersect the earth.
On the other hand, the atmosphere must limit how far you can see in practice. The result should be a soft, hazy horizon rather than the sharp horizon you see on earth on a clear day. It would probably appear that the land transitions to the sky in a kind of haze, with no visible line. (All assuming you have a clear line of site at 90 degrees.)
No the horizon would be at 90 degrees for a person of non-zero height on a flat earth only if it were also infinite in extent. Otherwise there would be a horizon at the angle s/he had to look down at to see the edge. The OP posits “a flat disk” which I take to mean finite in extent otherwise it would be called a plane. YIMV.
Imagine you are standing on a beach of a calm lake on a clear day. The far shore is 4 miles away.
On earth, assuming you are around 6 feet tall, you could not see the far shore. It’d be “under” your horizon.
On a flat world you would see the far shore with no problems.
The OP wanted to know what a flat world would look like and this would be a distinct difference from the sphere we live on. Not sure how far a human can see through our atmosphere on a clear day but I know in Chicago if you go to the top of the Willis (aka Sears) Tower you can see the state of Michigan across the lake. That is about 50 miles. So I would guess on a clear day on flat earth, with nothing to block your view, you should be able to see 50(ish) miles…maybe more.
Considering on earth your limit is 3 miles (assuming you are standing on the ground) I’d think the two vistas would look very different.
Nothing blocking your view is key though, and probably unlikely since the first thing ~6ft above your elevation cuts off everything behind it. Furthermore, at such a low elevation, everything gets crammed into the immediate vicinity of the horizon and I doubt you could make out anything in detail at all. Certainly you would not be able to make out a shoreline miles away, from an essentially head on angle.
So in general, I think your view would be pretty much the same on the ground. Of course getting high up is a different story. E.g., you also ought to be able to see large mountains from arbitrary distances provided they aren’t so far away as to have too small of apparent size.
On a clear day one can see an amazing distance. I’ve seen the top of Mount Rainier from just outside of Bellingham (on a really clear day), and that is around 150 miles. It helps that the mountain is over 14,000 high.
And yes, we do have a few really clear days up here in the Pacific Northwet.
Go to a beach. Chances are there will be few things sticking out of the water obstructing your view.
I live in Chicago and standing on the shore of Lake Michigan the horizon is about three miles away (to me).
On flat earth, even if I couldn’t see the state of Michigan (and not sure why I wouldn’t) I’d see a greater expanse of water than the three mile limit above.
Not saying you wouldn’t, but that doesn’t mean it would actually look different. I measure Michigan to be about 40 miles away. Say 0 degrees is looking at an infinite horizon (i.e., parallel to the ground) and 90 is straight down. Assuming you are 6 feet tall on the Chicago beach of a flat Earth, your line of sight to the Michigan coast is .0016 degrees. That means all the Earth from Michigan to infinity fits in that tiny angular range. I calculate seeing it would be equivalent to seeing a pea on the far side of a football field. Not gonna happen.
I also calculate, using wiki’s number of 2’ for the eye’s minimum resolution, that the coast would have to be 2.6 miles away to be able to see it. Not pick out details but just see that there is land, not water. Of course, as I said before, these numbers will change massively if you start elevating yourself above the terrain.
I think you are saying the land would not be distinguishable from the water. In fact there are things that stick up on the other side like trees which could be distinguished.
Let’s try it this way.
Daylate said he (or she as the case may be) could see Mt. Rainier from 150 miles away on a clear day. What is missing from that is he can only see a bit of the top of the mountain. The rest is below the horizon but being 14,000 feet high the top pokes above the horizon. Even if there was a perfectly flat plain between him and the mountain this would be the case. If the mountain wasn’t quite so high he wouldn’t see it at all.
Now imagine flat earth with nothing but a perfectly flat plain between him and the mountain. In this case, on a clear day, he’d see the whole mountain all the way down to its base. Even if it was the shorter mountain such that he wouldn’t see it on a round earth he still sees it on flat earth.
Does that make more sense as to what I am getting at?
It is true in most cases we have stuff around us blocking our views out to long distances but there would be cases where a difference would be noticed between flat/round earth and this would be one of them.